treeview.c

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/*
 * Copyright 2012 - 2013 Michael Drake <tlsa@netsurf-browser.org>
 *
 * This file is part of NetSurf, http://www.netsurf-browser.org/
 *
 * NetSurf is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * NetSurf is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
/**
 * \file
 *
 * Treeview handling implementation.
 */
 
#include "utils/config.h"
 
#include <string.h>
 
#include "utils/utils.h"
#include "utils/log.h"
#include "utils/nsurl.h"
#include "utils/nscolour.h"
#include "utils/nsoption.h"
#include "netsurf/bitmap.h"
#include "netsurf/content.h"
#include "netsurf/plotters.h"
#include "netsurf/clipboard.h"
#include "netsurf/layout.h"
#include "netsurf/keypress.h"
#include "netsurf/core_window.h"
#include "content/hlcache.h"
#include "css/utils.h"
 
#include "desktop/bitmap.h"
#include "desktop/knockout.h"
#include "desktop/textarea.h"
#include "desktop/treeview.h"
#include "desktop/cw_helper.h"
#include "desktop/gui_internal.h"
#include "desktop/system_colour.h"
 
/**
 * The maximum horizontal size a treeview can possibly be.
 *
 * \todo get rid of REDRAW_MAX -- need to be able to know window size
 */
#define REDRAW_MAX 8000
 
 
/**
 * Treeview handling global context
 */
struct treeview_globals {
        unsigned initialised;
        int line_height;
        int furniture_width;
        int step_width;
        int window_padding;
        int icon_size;
        int icon_step;
        int move_offset;
} tree_g;
 
 
/**
 * Section type of a treeview at a point
 */
enum treeview_node_part {
        TV_NODE_PART_TOGGLE,    /**< Expansion toggle */
        TV_NODE_PART_ON_NODE,   /**< Node content (text, icon) */
        TV_NODE_PART_NONE       /**< Empty area */
};
 
 
/**
 * Text within a treeview field or node
 */
struct treeview_text {
        const char *data;       /**< Text string */
        uint32_t len;           /**< Length of string in bytes */
        int width;              /**< Width of text in px */
};
 
 
/**
 * a treeview field
 */
struct treeview_field {
        /** flags controlling how field is interpreted */
        enum treeview_field_flags flags;
 
        lwc_string *field; /**< field contents */
        struct treeview_text value; /**< field text */
};
 
 
/**
 * flags indicating render state of node.
 */
enum treeview_node_flags {
        TV_NFLAGS_NONE     = 0,         /**< No node flags set */
        TV_NFLAGS_EXPANDED = (1 << 0),  /**< Whether node is expanded */
        TV_NFLAGS_SELECTED = (1 << 1),  /**< Whether node is selected */
        TV_NFLAGS_SPECIAL  = (1 << 2),  /**< Render as special node */
        TV_NFLAGS_MATCHED  = (1 << 3),  /**< Whether node matches search */
};
 
 
/**
 * Treeview target position
 */
enum treeview_target_pos {
        TV_TARGET_ABOVE,
        TV_TARGET_INSIDE,
        TV_TARGET_BELOW,
        TV_TARGET_NONE
};
 
 
/**
 * Treeview node
 */
struct treeview_node {
        enum treeview_node_flags flags; /**< Node flags */
        enum treeview_node_type type;   /**< Node type */
 
        int height;     /**< Includes height of any descendants (pixels) */
        int inset;      /**< Node's inset depending on tree depth (pixels) */
 
        treeview_node *parent; /**< parent node */
        treeview_node *prev_sib; /**< previous sibling node */
        treeview_node *next_sib; /**< next sibling node */
        treeview_node *children; /**< first child node */
 
        void *client_data;  /**< Passed to client on node event msg callback */
 
        struct treeview_text text; /** Text to show for node (default field) */
};
 
 
/**
 * Node entry
 *
 * node entry contains a base node at the beginning allowing for
 * trivial containerof by cast and some number of fields.
 */
struct treeview_node_entry {
        treeview_node base; /**< Entry class inherits node base class */
        struct treeview_field fields[FLEX_ARRAY_LEN_DECL];
};
 
 
/**
 * A mouse position wrt treeview
 */
struct treeview_pos {
        int x;          /**< Mouse X coordinate */
        int y;          /**< Mouse Y coordinate */
        int node_y;     /**< Top of node at y */
        int node_h;     /**< Height of node at y */
};
 
 
/**
 * Treeview drag state
 */
struct treeview_drag {
        enum {
                TV_DRAG_NONE,
                TV_DRAG_SELECTION,
                TV_DRAG_MOVE,
                TV_DRAG_TEXTAREA,
                TV_DRAG_SEARCH,
        } type; /**< Drag type */
        treeview_node *start_node;      /**< Start node */
        bool selected;                  /**< Start node is selected */
        enum treeview_node_part part;   /**< Node part at start */
        struct treeview_pos start;      /**< Start pos */
        struct treeview_pos prev;       /**< Previous pos */
};
 
 
/**
 * Treeview node move details
 */
struct treeview_move {
        treeview_node *root;            /**< Head of yanked node list */
        treeview_node *target;          /**< Move target */
        struct rect target_area;        /**< Pos/size of target indicator */
        enum treeview_target_pos target_pos;    /**< Pos wrt render node */
};
 
 
/**
 * Treeview node edit details
 */
struct treeview_edit {
        treeview_node *node;            /**< Node being edited, or NULL */
        struct textarea *textarea;      /**< Textarea for edit, or NULL */
        lwc_string *field;              /**< The field being edited, or NULL */
        int x;          /**< Textarea x position */
        int y;          /**< Textarea y position */
        int w;          /**< Textarea width */
        int h;          /**< Textarea height */
};
 
 
/**
 * Treeview search box details
 */
struct treeview_search {
        struct textarea *textarea;  /**< Search box. */
        bool active;                /**< Whether the search box has focus. */
        bool search;                /**< Whether we have a search term. */
        int height;                 /**< Current search display height. */
};
 
 
/**
 * The treeview context
 */
struct treeview {
        uint32_t view_width; /**< Viewport horizontal size */
 
        treeview_flags flags; /**< Treeview behaviour settings */
 
        treeview_node *root; /**< Root node */
 
        struct treeview_field *fields;  /**< Array of fields */
        int n_fields; /**< fields[n_fields] is folder, lower are entry fields */
        int field_width; /**< Max width of shown field names */
 
        struct treeview_drag drag; /**< Drag state */
        struct treeview_move move; /**< Move drag details */
        struct treeview_edit edit; /**< Edit details */
 
        struct treeview_search search; /**< Treeview search box */
 
        const struct treeview_callback_table *callbacks; /**< For node events */
 
        const struct core_window_callback_table *cw_t; /**< Window cb table */
        struct core_window *cw_h; /**< Core window handle */
};
 
 
/**
 * Treeview furniture states.
 */
enum treeview_furniture_id {
        TREE_FURN_EXPAND = 0,
        TREE_FURN_CONTRACT,
        TREE_FURN_LAST
};
 
 
/**
 * style for a node
 */
struct treeview_node_style {
        plot_style_t bg;          /**< Background */
        plot_font_style_t text;   /**< Text */
        plot_font_style_t itext;  /**< Entry field text */
 
        plot_style_t sbg;         /**< Selected background */
        plot_font_style_t stext;  /**< Selected text */
        plot_font_style_t sitext; /**< Selected entry field text */
 
        struct {
                int size;
                struct bitmap *bmp;
                struct bitmap *sel;
        } furn[TREE_FURN_LAST];
};
 
 
/**
 * Plot style for odd rows
 */
struct treeview_node_style plot_style_odd;
 
 
/**
 * Plot style for even rows
 */
struct treeview_node_style plot_style_even;
 
 
/**
 * Treeview content resource data
 */
struct treeview_resource {
        const char *url;
        struct hlcache_handle *c;
        int height;
        bool ready;
};
 
 
/**
 * treeview resource indexes
 */
enum treeview_resource_id {
        TREE_RES_ARROW = 0,
        TREE_RES_CONTENT,
        TREE_RES_FOLDER,
        TREE_RES_FOLDER_SPECIAL,
        TREE_RES_SEARCH,
        TREE_RES_LAST
};
 
 
/**
 * Treeview content resources
 */
static struct treeview_resource treeview_res[TREE_RES_LAST] = {
        { "resource:icons/arrow-l.png", NULL, 0, false },
        { "resource:icons/content.png", NULL, 0, false },
        { "resource:icons/directory.png", NULL, 0, false },
        { "resource:icons/directory2.png", NULL, 0, false },
        { "resource:icons/search.png", NULL, 0, false }
};
 
 
/**
 * Get the display height of the treeview data component of the display.
 *
 * \param[in] tree  Treeview to get the height of.
 * \return the display height in pixels.
 */
static inline int treeview__get_display_height(const treeview *tree)
{
        return (tree->search.search == false) ?
                        tree->root->height :
                        tree->search.height;
}
 
 
/**
 * Corewindow callback wrapper: Request a redraw of the window
 *
 * \param[in] tree The treeview to request redraw on.
 * \param[in] r rectangle to redraw
 */
static inline void treeview__cw_invalidate_area(
                const struct treeview *tree,
                const struct rect *r)
{
        if (tree->cw_t != NULL) {
                tree->cw_t->invalidate(tree->cw_h, r);
        }
}
 
 
/**
 * Corewindow callback wrapper: Request a full redraw of the window
 *
 * \param[in] tree The treeview to request redraw on.
 */
static inline void treeview__cw_full_redraw(
                const struct treeview *tree)
{
        if (tree->cw_t != NULL) {
                static const struct rect r = {
                        .x0 = 0,
                        .y0 = 0,
                        .x1 = REDRAW_MAX,
                        .y1 = REDRAW_MAX,
                };
                tree->cw_t->invalidate(tree->cw_h, &r);
        }
}
 
 
/**
 * Get height used by treeview's search bar (or 0 if not present).
 *
 * \param tree    Treeview object to check.
 * \return height used by search bar in pixels.
 */
static inline unsigned treeview__get_search_height(
                const treeview *tree)
{
        return (tree->flags & TREEVIEW_SEARCHABLE) ?
                        tree_g.line_height : 0;
}
 
 
/**
 * Corewindow callback wrapper: Update the limits of the window
 *
 * \param[in] tree The treeview to update size for.
 * \param[in] width the width in px, or negative if don't care
 * \param[in] height the height in px, or negative if don't care
 */
static inline void treeview__cw_update_size(
        const struct treeview *tree,
        int width, int height)
{
        if (tree->cw_t != NULL) {
                tree->cw_t->update_size(tree->cw_h, width,
                                height + treeview__get_search_height(tree));
        }
}
 
 
/**
 * Corewindow callback_wrapper: Scroll to top of window.
 *
 * \param[in] tree  The treeview to scroll.
 */
static inline void treeview__cw_scroll_top(
                const struct treeview *tree)
{
        struct rect r = {
                .x0 = 0,
                .y0 = 0,
                .x1 = tree_g.window_padding,
                .y1 = tree_g.line_height,
        };
 
        cw_helper_scroll_visible(tree->cw_t, tree->cw_h, &r);
}
 
 
/**
 * Corewindow callback wrapper: Get window viewport dimensions
 *
 * \param[in] tree The treeview to get dimensions for.
 * \param[out] width to be set to viewport width in px
 * \param[out] height to be set to viewport height in px
 */
static inline void treeview__cw_get_window_dimensions(
        const struct treeview *tree,
        int *width, int *height)
{
        if (tree->cw_t != NULL) {
                tree->cw_t->get_window_dimensions(tree->cw_h, width, height);
        }
}
 
 
/**
 * Corewindow callback wrapper: Inform corewindow owner of drag status
 *
 * \param[in] tree The treeview to report status on.
 * \param[in] ds the current drag status
 */
static inline void treeview__cw_drag_status(
        const struct treeview *tree,
        core_window_drag_status ds)
{
        if (tree->cw_t != NULL) {
                tree->cw_t->drag_status(tree->cw_h, ds);
        }
}
 
 
/**
 * Helper function to access the given field of a node
 *
 * \param tree Treeview that node belongs to
 * \param n Node to get field from
 * \param i Index of field of interest
 * \return text entry for field or NULL.
 */
static inline struct treeview_text *
treeview_get_text_for_field(treeview *tree, treeview_node *n, int i)
{
        if (i == 0) {
                return &n->text;
 
        } else if (i < tree->n_fields && n->type == TREE_NODE_ENTRY) {
                struct treeview_node_entry *e = (struct treeview_node_entry *)n;
                return &e->fields[i - 1].value;
        }
 
        assert(0 && "Bad field index for node");
        return NULL;
}
 
 
/**
 * Find the next node in depth first tree order
 *
 * \param node Start node
 * \param full Iff true, visit children of collapsed nodes
 * \return next node, or NULL if \a node is last node
 */
static inline treeview_node * treeview_node_next(treeview_node *node, bool full)
{
        assert(node != NULL);
 
        if ((full || (node->flags & TV_NFLAGS_EXPANDED)) &&
            node->children != NULL) {
                /* Next node is child */
                node = node->children;
        } else {
                /* No children.  As long as we're not at the root,
                 * go to next sibling if present, or nearest ancestor
                 * with a next sibling. */
 
                while (node->parent != NULL && node->next_sib == NULL) {
                        node = node->parent;
                }
 
                if (node->type == TREE_NODE_ROOT) {
                        node = NULL;
 
                } else {
                        node = node->next_sib;
                }
        }
 
        return node;
}
 
 
/**
 * Find node at given y-position
 *
 * \param tree Treeview object to delete node from
 * \param target_y Target y-position
 * \return node at y_target
 */
static treeview_node * treeview_y_node(treeview *tree, int target_y)
{
        int y = treeview__get_search_height(tree);
        treeview_node *n;
 
        assert(tree != NULL);
        assert(tree->root != NULL);
 
        n = treeview_node_next(tree->root, false);
 
        while (n != NULL) {
                int h = (n->type == TREE_NODE_ENTRY) ?
                        n->height : tree_g.line_height;
                if (target_y >= y && target_y < y + h)
                        return n;
                y += h;
 
                n = treeview_node_next(n, false);
        }
 
        return NULL;
}
 
 
/**
 * Find y position of the top of a node
 *
 * \param tree Treeview object to delete node from
 * \param node Node to get position of
 * \return node's y position
 */
static int treeview_node_y(
                const treeview *tree,
                const treeview_node *node)
{
        treeview_node *n;
        int y = treeview__get_search_height(tree);
 
        assert(tree != NULL);
        assert(tree->root != NULL);
 
        n = treeview_node_next(tree->root, false);
 
        while (n != NULL && n != node) {
                y += (n->type == TREE_NODE_ENTRY) ?
                        n->height : tree_g.line_height;
 
                n = treeview_node_next(n, false);
        }
 
        return y;
}
 
 
/**
 * Corewindow callback_wrapper: Scroll to make node visible
 *
 * \param[in] tree  The treeview to scroll.
 * \param[in] node  The treeview node to scroll to visibility.
 */
static inline void treeview__cw_scroll_to_node(
                const struct treeview *tree,
                const struct treeview_node *node)
{
        struct rect r = {
                .x0 = 0,
                .y0 = treeview_node_y(tree, node),
                .x1 = 1,
                .y1 = ((node->type == TREE_NODE_ENTRY) ?
                       node->height : tree_g.line_height),
        };
 
        r.y1 += r.y0; /* Apply the Y offset to the second Y coordinate */
 
        cw_helper_scroll_visible(tree->cw_t, tree->cw_h, &r);
}
 
 
/**
 * Redraw tree from given node to the bottom.
 *
 * \param[in] tree  Tree to redraw from node in.
 * \param[in] node  Node to redraw from.
 */
static void treeview__redraw_from_node(
                const treeview *tree,
                const treeview_node *node)
{
        struct rect r = {
                .x0 = 0,
                .y0 = treeview_node_y(tree, node),
                .x1 = REDRAW_MAX,
                .y1 = treeview__get_display_height(tree) +
                                treeview__get_search_height(tree),
        };
 
        assert(tree != NULL);
 
        treeview__cw_invalidate_area(tree, &r);
}
 
 
/**
 * The treeview walk mode.  Controls which nodes are visited in a walk.
 */
enum treeview_walk_mode {
        /**
         * Walk to all nodes in the (sub)tree.
         */
        TREEVIEW_WALK_MODE_LOGICAL_COMPLETE,
 
        /**
         * Walk to expanded nodes in the (sub)tree only.  Children of
         * collapsed nodes are not visited.
         */
        TREEVIEW_WALK_MODE_LOGICAL_EXPANDED,
 
        /**
         * Walk displayed nodes.  This differs from the
         * `TREEVIEW_WALK_MODE_LOGICAL_EXPANDED` mode when there is
         * an active search filter display.
         */
        TREEVIEW_WALK_MODE_DISPLAY,
};
 
 
/**
 * Walk a treeview subtree, calling a callback at each node (depth first)
 *
 * \param tree          Treeview being walked.
 * \param root          Root to walk tree from (doesn't get a callback call)
 * \param mode          The treeview walk mode to use.
 * \param callback_bwd  Function to call on each node in backwards order
 * \param callback_fwd  Function to call on each node in forwards order
 * \param ctx           Context to pass to callback
 * \return NSERROR_OK on success, or appropriate error otherwise
 *
 * \note Any node deletion must happen in callback_bwd.
 */
static nserror treeview_walk_internal(
                treeview *tree,
                treeview_node *root,
                enum treeview_walk_mode mode,
                nserror (*callback_bwd)(
                                treeview_node *n,
                                void *ctx,
                                bool *end),
                nserror (*callback_fwd)(
                                treeview_node *n,
                                void *ctx,
                                bool *skip_children,
                                bool *end),
                void *ctx)
{
        treeview_node *node, *child, *parent, *next_sibling;
        bool walking_search = (mode == TREEVIEW_WALK_MODE_DISPLAY &&
                        tree->search.search == true);
        bool skip_children = false;
        bool abort = false;
        bool full = false;
        nserror err;
        bool entry;
 
        assert(root != NULL);
 
        if (mode == TREEVIEW_WALK_MODE_LOGICAL_COMPLETE || walking_search) {
                /* We need to visit children of collapsed folders. */
                full = true;
        }
 
        node = root;
        parent = node->parent;
        next_sibling = node->next_sib;
        child = (full || (node->flags & TV_NFLAGS_EXPANDED)) ?
                node->children : NULL;
 
        while (node != NULL) {
 
                if (child != NULL && !skip_children) {
                        /* Down to children */
                        node = child;
                } else {
                        /* No children.  As long as we're not at the root,
                         * go to next sibling if present, or nearest ancestor
                         * with a next sibling. */
 
                        while (node != root && next_sibling == NULL) {
                                entry = (node->type == TREE_NODE_ENTRY);
                                if (callback_bwd != NULL &&
                                                (entry || !walking_search)) {
                                        /* Backwards callback */
                                        err = callback_bwd(node, ctx, &abort);
 
                                        if (err != NSERROR_OK) {
                                                return err;
 
                                        } else if (abort) {
                                                /* callback requested early
                                                 * termination */
                                                return NSERROR_OK;
                                        }
                                }
                                node = parent;
                                parent = node->parent;
                                next_sibling = node->next_sib;
                        }
 
                        if (node == root)
                                break;
 
                        if (callback_bwd != NULL) {
                                /* Backwards callback */
                                err = callback_bwd(node, ctx, &abort);
 
                                if (err != NSERROR_OK) {
                                        return err;
 
                                } else if (abort) {
                                        /* callback requested early
                                         * termination */
                                        return NSERROR_OK;
                                }
                        }
                        node = next_sibling;
                }
 
                assert(node != NULL);
                assert(node != root);
 
                entry = (node->type == TREE_NODE_ENTRY);
 
                parent = node->parent;
                next_sibling = node->next_sib;
                child = (full || (node->flags & TV_NFLAGS_EXPANDED)) ?
                        node->children : NULL;
 
                if (walking_search && (!entry ||
                                !(node->flags & TV_NFLAGS_MATCHED))) {
                        continue;
                }
 
                if (callback_fwd != NULL) {
                        /* Forwards callback */
                        err = callback_fwd(node, ctx, &skip_children, &abort);
 
                        if (err != NSERROR_OK) {
                                return err;
 
                        } else if (abort) {
                                /* callback requested early termination */
                                return NSERROR_OK;
                        }
                }
        }
        return NSERROR_OK;
}
 
 
/**
 * Data used when doing a treeview walk for search.
 */
struct treeview_search_walk_data {
        treeview *tree;          /**< The treeview to search. */
        const char *text;        /**< The string being searched for. */
        const unsigned int len;  /**< Length of string being searched for. */
        int window_height;       /**< Accumulate height for matching entries. */
};
 
 
/**
 * Treewalk node callback for handling search.
 *
 * \param[in]     n              Current node.
 * \param[in]     ctx            Treeview search context.
 * \param[in,out] skip_children  Flag to allow children to be skipped.
 * \param[in,out] end            Flag to allow iteration to be finished early.
 * \return NSERROR_OK on success else error code.
 */
static nserror treeview__search_walk_cb(
                treeview_node *n,
                void *ctx,
                bool *skip_children,
                bool *end)
{
        struct treeview_search_walk_data *sw = ctx;
 
        if (n->type != TREE_NODE_ENTRY) {
                return NSERROR_OK;
        }
 
        if (sw->len == 0) {
                n->flags &= ~TV_NFLAGS_MATCHED;
        } else {
                struct treeview_node_entry *entry =
                                (struct treeview_node_entry *)n;
                bool matched = false;
 
                for (int i = 0; i < sw->tree->n_fields; i++) {
                        struct treeview_field *ef = &(sw->tree->fields[i + 1]);
                        if (ef->flags & TREE_FLAG_SEARCHABLE) {
                                if (strcasestr(entry->fields[i].value.data,
                                                sw->text) != NULL) {
                                        matched = true;
                                        break;
                                }
                        }
                }
 
                if (!matched && strcasestr(n->text.data, sw->text) != NULL) {
                        matched = true;
                }
 
                if (matched) {
                        n->flags |= TV_NFLAGS_MATCHED;
                        sw->window_height += n->height;
                } else {
                        n->flags &= ~TV_NFLAGS_MATCHED;
                }
        }
 
        return NSERROR_OK;
}
 
 
/**
 * Search treeview for text.
 *
 * \param[in] tree  Treeview to search.
 * \param[in] text  UTF-8 string to search for.  (NULL-terminated.)
 * \param[in] len   Byte length of UTF-8 string.
 * \return NSERROR_OK on success, appropriate error otherwise.
 */
static nserror treeview__search(
                treeview *tree,
                const char *text,
                unsigned int len)
{
        nserror err;
        uint32_t height;
        uint32_t prev_height = treeview__get_display_height(tree);
        int search_height = treeview__get_search_height(tree);
        struct treeview_search_walk_data sw = {
                .len = len,
                .text = text,
                .tree = tree,
                .window_height = 0,
        };
        struct rect r = {
                .x0 = 0,
                .y0 = search_height,
                .x1 = REDRAW_MAX,
        };
 
        assert(text[len] == '\0');
 
        if (tree->root == NULL) {
                return NSERROR_OK;
        }
 
        err = treeview_walk_internal(tree, tree->root,
                        TREEVIEW_WALK_MODE_LOGICAL_COMPLETE, NULL,
                        treeview__search_walk_cb, &sw);
        if (err != NSERROR_OK) {
                return err;
        }
 
        if (len > 0) {
                tree->search.height = sw.window_height;
                tree->search.search = true;
                height = sw.window_height;
        } else {
                tree->search.search = false;
                height = tree->root->height;
        }
 
        r.y1 = ((height > prev_height) ? height : prev_height) + search_height;
        treeview__cw_invalidate_area(tree, &r);
        treeview__cw_update_size(tree, -1, height);
        treeview__cw_scroll_top(tree);
 
        return NSERROR_OK;
}
 
 
/**
 * Cancel a treeview search, optionally droping focus from search widget.
 *
 * \param[in] tree        Treeview to cancel search in.
 * \param[in] drop_focus  Iff true, drop input focus from search widget.
 */
static void treeview__search_cancel(treeview *tree, bool drop_focus)
{
        struct rect r = {
                .x0 = tree_g.window_padding + tree_g.icon_size,
                .x1 = 600,
                .y0 = 0,
                .y1 = tree_g.line_height,
        };
 
        tree->search.search = false;
        if (tree->search.active == false) {
                return;
        }
 
        if (textarea_get_text(tree->search.textarea, NULL, 0) == 1) {
                // If there's no text in the search box, we drop focus on a
                // cancel.  Note '1' because it includes the trailing \0
                drop_focus = true;
        }
 
        if (drop_focus) {
                tree->search.active = false;
                textarea_set_caret(tree->search.textarea, -1);
        } else {
                textarea_set_caret(tree->search.textarea, 0);
        }
 
        textarea_set_text(tree->search.textarea, "");
        treeview__cw_invalidate_area(tree, &r);
}
 
/**
 * Convert from treeview drag to core window drag type.
 *
 * \param[in]  tree  A treeview.
 * \return Core window drag type.
 */
static core_window_drag_status treeview__get_cw_drag_type(
                const treeview *tree)
{
        assert(tree != NULL);
 
        switch (tree->drag.type) {
        case TV_DRAG_NONE:
                return CORE_WINDOW_DRAG_NONE;
 
        case TV_DRAG_SELECTION:
                return CORE_WINDOW_DRAG_SELECTION;
 
        case TV_DRAG_TEXTAREA: /* Fall through.*/
        case TV_DRAG_SEARCH:
                return CORE_WINDOW_DRAG_TEXT_SELECTION;
 
        case TV_DRAG_MOVE:
                return CORE_WINDOW_DRAG_MOVE;
        }
 
        return CORE_WINDOW_DRAG_NONE;
}
 
/**
 * Callback for textarea_create, in desktop/treeview.h
 *
 * \param data treeview context
 * \param msg textarea message
 */
static void treeview_textarea_search_callback(void *data,
                struct textarea_msg *msg)
{
        treeview *tree = data;
        struct rect *r;
 
        if (tree->search.active == false || tree->root == NULL) {
                return;
        }
 
        switch (msg->type) {
        case TEXTAREA_MSG_DRAG_REPORT:
                if (msg->data.drag == TEXTAREA_DRAG_NONE) {
                        /* Textarea drag finished */
                        tree->drag.type = TV_DRAG_NONE;
                } else {
                        /* Textarea drag started */
                        tree->drag.type = TV_DRAG_SEARCH;
                }
                treeview__cw_drag_status(tree,
                                treeview__get_cw_drag_type(tree));
                break;
 
        case TEXTAREA_MSG_REDRAW_REQUEST:
                r = &msg->data.redraw;
                r->x0 += tree_g.window_padding + tree_g.icon_size;
                r->y0 += 0;
                r->x1 += 600;
                r->y1 += tree_g.line_height;
 
                /* Redraw the textarea */
                treeview__cw_invalidate_area(tree, r);
                break;
 
        case TEXTAREA_MSG_TEXT_MODIFIED:
                /* Textarea length includes trailing NULL, so subtract it. */
                treeview__search(tree,
                                msg->data.modified.text,
                                msg->data.modified.len - 1);
                break;
 
        default:
                break;
        }
}
 
 
/**
 * Update the layout for any active search.
 *
 * \param[in] tree  The tree to update.
 */
static void treeview__search_update_display(
                treeview *tree)
{
        const char *string;
        unsigned int len;
 
        if (tree->search.search == false) {
                /* No active search to update view for. */
                return;
        }
 
        string = textarea_data(tree->search.textarea, &len);
        if (string == NULL || len == 0) {
                return;
        }
 
        treeview__search(tree, string, len - 1);
}
 
 
/**
 * Create treeview's root node
 *
 * \param[out] root Returns root node
 * \return NSERROR_OK on success, appropriate error otherwise
 */
static nserror treeview_create_node_root(treeview_node **root)
{
        treeview_node *n;
 
        n = malloc(sizeof(struct treeview_node));
        if (n == NULL) {
                return NSERROR_NOMEM;
        }
 
        n->flags = TV_NFLAGS_EXPANDED;
        n->type = TREE_NODE_ROOT;
 
        n->height = 0;
        n->inset = tree_g.window_padding - tree_g.step_width;
 
        n->text.data = NULL;
        n->text.len = 0;
        n->text.width = 0;
 
        n->parent = NULL;
        n->next_sib = NULL;
        n->prev_sib = NULL;
        n->children = NULL;
 
        n->client_data = NULL;
 
        *root = n;
 
        return NSERROR_OK;
}
 
 
/**
 * Set a node's inset from its parent
 *
 * This may be used as treeview walk callback
 *
 * \param[in] n node to set inset on
 * \param[in] ctx context unused
 * \param[out] skip_children set to false so child nodes are not skipped.
 * \param[out] end unused flag so treewalk in not terminated early.
 */
static nserror
treeview_set_inset_from_parent(treeview_node *n,
                               void *ctx,
                               bool *skip_children,
                               bool *end)
{
        if (n->parent != NULL)
                n->inset = n->parent->inset + tree_g.step_width;
 
        *skip_children = false;
        return NSERROR_OK;
}
 
 
/**
 * Insert a treeview node into a treeview
 *
 * \param tree  the treeview to insert node into.
 * \param a     parentless node to insert
 * \param b     tree node to insert a as a relation of
 * \param rel The relationship between \a a and \a b
 */
static inline void
treeview_insert_node(
                treeview *tree,
                treeview_node *a,
                treeview_node *b,
                enum treeview_relationship rel)
{
        assert(a != NULL);
        assert(a->parent == NULL);
        assert(b != NULL);
 
        switch (rel) {
        case TREE_REL_FIRST_CHILD:
                assert(b->type != TREE_NODE_ENTRY);
                a->parent = b;
                a->next_sib = b->children;
                if (a->next_sib)
                        a->next_sib->prev_sib = a;
                b->children = a;
                break;
 
        case TREE_REL_NEXT_SIBLING:
                assert(b->type != TREE_NODE_ROOT);
                a->prev_sib = b;
                a->next_sib = b->next_sib;
                a->parent = b->parent;
                b->next_sib = a;
                if (a->next_sib)
                        a->next_sib->prev_sib = a;
                break;
 
        default:
                assert(0);
                break;
        }
 
        assert(a->parent != NULL);
 
        a->inset = a->parent->inset + tree_g.step_width;
        if (a->children != NULL) {
                treeview_walk_internal(tree, a,
                                TREEVIEW_WALK_MODE_LOGICAL_COMPLETE, NULL,
                                treeview_set_inset_from_parent, NULL);
        }
 
        if (a->parent->flags & TV_NFLAGS_EXPANDED) {
                int height = a->height;
                /* Parent is expanded, so inserted node will be visible and
                 * affect layout */
                if (a->text.width == 0) {
                        guit->layout->width(&plot_style_odd.text,
                                            a->text.data,
                                            a->text.len,
                                            &(a->text.width));
                }
 
                do {
                        a->parent->height += height;
                        a = a->parent;
                } while (a->parent != NULL);
        }
}
 
 
/* Exported interface, documented in treeview.h */
nserror
treeview_create_node_folder(treeview *tree,
                            treeview_node **folder,
                            treeview_node *relation,
                            enum treeview_relationship rel,
                            const struct treeview_field_data *field,
                            void *data,
                            treeview_node_options_flags flags)
{
        treeview_node *n;
 
        assert(data != NULL);
        assert(tree != NULL);
        assert(tree->root != NULL);
 
        if (relation == NULL) {
                relation = tree->root;
                rel = TREE_REL_FIRST_CHILD;
        }
 
        n = malloc(sizeof(struct treeview_node));
        if (n == NULL) {
                return NSERROR_NOMEM;
        }
 
        n->flags = (flags & TREE_OPTION_SPECIAL_DIR) ?
                TV_NFLAGS_SPECIAL : TV_NFLAGS_NONE;
        n->type = TREE_NODE_FOLDER;
 
        n->height = tree_g.line_height;
 
        n->text.data = field->value;
        n->text.len = field->value_len;
        n->text.width = 0;
 
        n->parent = NULL;
        n->next_sib = NULL;
        n->prev_sib = NULL;
        n->children = NULL;
 
        n->client_data = data;
 
        treeview_insert_node(tree, n, relation, rel);
 
        if (n->parent->flags & TV_NFLAGS_EXPANDED) {
                /* Inform front end of change in dimensions */
                if (!(flags & TREE_OPTION_SUPPRESS_RESIZE))
                        treeview__cw_update_size(tree, -1,
                                                 tree->root->height);
 
                /* Redraw */
                if (!(flags & TREE_OPTION_SUPPRESS_REDRAW)) {
                        struct rect r;
                        r.x0 = 0;
                        r.y0 = treeview_node_y(tree, n);
                        r.x1 = REDRAW_MAX;
                        r.y1 = tree->root->height;
                        treeview__cw_invalidate_area(tree, &r);
                }
        }
 
        *folder = n;
 
        return NSERROR_OK;
}
 
 
/* Exported interface, documented in treeview.h */
nserror
treeview_update_node_folder(treeview *tree,
                            treeview_node *folder,
                            const struct treeview_field_data *field,
                            void *data)
{
        bool match;
 
        assert(data != NULL);
        assert(tree != NULL);
        assert(folder != NULL);
        assert(data == folder->client_data);
        assert(folder->parent != NULL);
 
        assert(field != NULL);
        assert(lwc_string_isequal(tree->fields[tree->n_fields].field,
                                  field->field, &match) == lwc_error_ok &&
               match == true);
        folder->text.data = field->value;
        folder->text.len = field->value_len;
        folder->text.width = 0;
 
        if (folder->parent->flags & TV_NFLAGS_EXPANDED) {
                /* Text will be seen, get its width */
                guit->layout->width(&plot_style_odd.text,
                                    folder->text.data,
                                    folder->text.len,
                                    &(folder->text.width));
        } else {
                /* Just invalidate the width, since it's not needed now */
                folder->text.width = 0;
        }
 
        /* Redraw */
        if (folder->parent->flags & TV_NFLAGS_EXPANDED) {
                struct rect r;
                r.x0 = 0;
                r.y0 = treeview_node_y(tree, folder);
                r.x1 = REDRAW_MAX;
                r.y1 = r.y0 + tree_g.line_height;
                treeview__cw_invalidate_area(tree, &r);
        }
 
        return NSERROR_OK;
}
 
 
/* Exported interface, documented in treeview.h */
nserror
treeview_update_node_entry(treeview *tree,
                           treeview_node *entry,
                           const struct treeview_field_data fields[],
                           void *data)
{
        bool match;
        struct treeview_node_entry *e = (struct treeview_node_entry *)entry;
        int i;
 
        assert(data != NULL);
        assert(tree != NULL);
        assert(entry != NULL);
        assert(data == entry->client_data);
        assert(entry->parent != NULL);
 
        assert(fields != NULL);
        assert(fields[0].field != NULL);
        assert(lwc_string_isequal(tree->fields[0].field,
                                  fields[0].field, &match) == lwc_error_ok &&
               match == true);
        entry->text.data = fields[0].value;
        entry->text.len = fields[0].value_len;
        entry->text.width = 0;
 
        if (entry->parent->flags & TV_NFLAGS_EXPANDED) {
                /* Text will be seen, get its width */
                guit->layout->width(&plot_style_odd.text,
                                    entry->text.data,
                                    entry->text.len,
                                    &(entry->text.width));
        } else {
                /* Just invalidate the width, since it's not needed now */
                entry->text.width = 0;
        }
 
        for (i = 1; i < tree->n_fields; i++) {
                assert(fields[i].field != NULL);
                assert(lwc_string_isequal(tree->fields[i].field,
                                          fields[i].field, &match) == lwc_error_ok &&
                       match == true);
 
                e->fields[i - 1].value.data = fields[i].value;
                e->fields[i - 1].value.len = fields[i].value_len;
 
                if (entry->flags & TV_NFLAGS_EXPANDED) {
                        /* Text will be seen, get its width */
                        guit->layout->width(&plot_style_odd.text,
                                            e->fields[i - 1].value.data,
                                            e->fields[i - 1].value.len,
                                            &(e->fields[i - 1].value.width));
                } else {
                        /* Invalidate the width, since it's not needed yet */
                        e->fields[i - 1].value.width = 0;
                }
        }
 
        treeview__search_update_display(tree);
 
        /* Redraw */
        if (entry->parent->flags & TV_NFLAGS_EXPANDED) {
                struct rect r;
                r.x0 = 0;
                r.y0 = treeview_node_y(tree, entry);
                r.x1 = REDRAW_MAX;
                r.y1 = r.y0 + entry->height;
                treeview__cw_invalidate_area(tree, &r);
        }
 
        return NSERROR_OK;
}
 
 
/* Exported interface, documented in treeview.h */
nserror
treeview_create_node_entry(treeview *tree,
                           treeview_node **entry,
                           treeview_node *relation,
                           enum treeview_relationship rel,
                           const struct treeview_field_data fields[],
                           void *data,
                           treeview_node_options_flags flags)
{
        bool match;
        struct treeview_node_entry *e;
        treeview_node *n;
        int i;
 
        assert(data != NULL);
        assert(tree != NULL);
        assert(tree->root != NULL);
 
        if (relation == NULL) {
                relation = tree->root;
                rel = TREE_REL_FIRST_CHILD;
        }
 
        e = malloc(sizeof(struct treeview_node_entry) +
                        (tree->n_fields - 1) * sizeof(struct treeview_field));
        if (e == NULL) {
                return NSERROR_NOMEM;
        }
 
 
        n = (treeview_node *) e;
 
        n->flags = TV_NFLAGS_NONE;
        n->type = TREE_NODE_ENTRY;
 
        n->height = tree_g.line_height;
 
        assert(fields != NULL);
        assert(fields[0].field != NULL);
        assert(lwc_string_isequal(tree->fields[0].field,
                        fields[0].field, &match) == lwc_error_ok &&
                        match == true);
        n->text.data = fields[0].value;
        n->text.len = fields[0].value_len;
        n->text.width = 0;
 
        n->parent = NULL;
        n->next_sib = NULL;
        n->prev_sib = NULL;
        n->children = NULL;
 
        n->client_data = data;
 
        for (i = 1; i < tree->n_fields; i++) {
                assert(fields[i].field != NULL);
                assert(lwc_string_isequal(tree->fields[i].field,
                                fields[i].field, &match) == lwc_error_ok &&
                                match == true);
 
                e->fields[i - 1].value.data = fields[i].value;
                e->fields[i - 1].value.len = fields[i].value_len;
                e->fields[i - 1].value.width = 0;
        }
 
        treeview_insert_node(tree, n, relation, rel);
 
        if (n->parent->flags & TV_NFLAGS_EXPANDED) {
                /* Inform front end of change in dimensions */
                if (!(flags & TREE_OPTION_SUPPRESS_RESIZE))
                        treeview__cw_update_size(tree, -1,
                                                 tree->root->height);
 
                /* Redraw */
                if (!(flags & TREE_OPTION_SUPPRESS_REDRAW)) {
                        struct rect r;
                        r.x0 = 0;
                        r.y0 = treeview_node_y(tree, n);
                        r.x1 = REDRAW_MAX;
                        r.y1 = tree->root->height;
                        treeview__cw_invalidate_area(tree, &r);
                }
        }
 
        treeview__search_update_display(tree);
 
        *entry = n;
 
        return NSERROR_OK;
}
 
 
/**
 * Treewalk iterator context
 */
struct treeview_walk_ctx {
        treeview_walk_cb enter_cb;
        treeview_walk_cb leave_cb;
        void *ctx;
        enum treeview_node_type type;
};
 
 
/**
 * Treewalk node enter callback.
 *
 * \param n current node
 * \param ctx treewalk context
 * \param skip_children set if child nodes should be skipped
 * \param end set if iteration should end early
 */
static nserror
treeview_walk_fwd_cb(treeview_node *n,
                     void *ctx,
                     bool *skip_children,
                     bool *end)
{
        struct treeview_walk_ctx *tw = ctx;
 
        if (n->type & tw->type) {
                return tw->enter_cb(tw->ctx, n->client_data, n->type, end);
        }
 
        return NSERROR_OK;
}
 
 
/**
 * Treewalk node leave callback.
 *
 * \param n current node
 * \param ctx treewalk context
 * \param end set if iteration should end early
 */
static nserror treeview_walk_bwd_cb(treeview_node *n, void *ctx, bool *end)
{
        struct treeview_walk_ctx *tw = ctx;
 
        if (n->type & tw->type) {
                return tw->leave_cb(tw->ctx, n->client_data, n->type, end);
        }
 
        return NSERROR_OK;
}
 
 
/* Exported interface, documented in treeview.h */
nserror
treeview_walk(treeview *tree,
              treeview_node *root,
              treeview_walk_cb enter_cb,
              treeview_walk_cb leave_cb,
              void *ctx,
              enum treeview_node_type type)
{
        struct treeview_walk_ctx tw = {
                .enter_cb = enter_cb,
                .leave_cb = leave_cb,
                .ctx = ctx,
                .type = type
        };
 
        assert(tree != NULL);
        assert(tree->root != NULL);
 
        if (root == NULL)
                root = tree->root;
 
        return treeview_walk_internal(tree, root,
                        TREEVIEW_WALK_MODE_LOGICAL_COMPLETE,
                        (leave_cb != NULL) ? treeview_walk_bwd_cb : NULL,
                        (enter_cb != NULL) ? treeview_walk_fwd_cb : NULL,
                        &tw);
}
 
 
/**
 * Unlink a treeview node
 *
 * \param n Node to unlink
 * \return true iff ancestor heights need to be reduced
 */
static inline bool treeview_unlink_node(treeview_node *n)
{
        /* Unlink node from tree */
        if (n->parent != NULL && n->parent->children == n) {
                /* Node is a first child */
                n->parent->children = n->next_sib;
 
        } else if (n->prev_sib != NULL) {
                /* Node is not first child */
                n->prev_sib->next_sib = n->next_sib;
        }
 
        if (n->next_sib != NULL) {
                /* Always need to do this */
                n->next_sib->prev_sib = n->prev_sib;
        }
 
        /* Reduce ancestor heights */
        if ((n->parent != NULL) &&
            (n->parent->flags & TV_NFLAGS_EXPANDED)) {
                return true;
        }
 
        return false;
}
 
 
/**
 * Cancel the editing of a treeview node
 *
 * \param tree Treeview object to cancel node editing in
 * \param redraw Set true iff redraw of removed textarea area required
 */
static void treeview_edit_cancel(treeview *tree, bool redraw)
{
        struct rect r;
 
        if (tree->edit.textarea == NULL)
                return;
 
        textarea_destroy(tree->edit.textarea);
 
        tree->edit.textarea = NULL;
        tree->edit.node = NULL;
 
        if (tree->drag.type == TV_DRAG_TEXTAREA)
                tree->drag.type = TV_DRAG_NONE;
 
        if (redraw) {
                r.x0 = tree->edit.x;
                r.y0 = tree->edit.y;
                r.x1 = tree->edit.x + tree->edit.w;
                r.y1 = tree->edit.y + tree->edit.h;
                treeview__cw_invalidate_area(tree, &r);
        }
}
 
 
/**
 * Complete a treeview edit
 *
 * Complete edit by informing the client with a change request msg
 *
 * \param tree Treeview object to complete edit in
 */
static void treeview_edit_done(treeview *tree)
{
        int len, error;
        char* new_text;
        treeview_node *n = tree->edit.node;
        struct treeview_node_msg msg;
        msg.msg = TREE_MSG_NODE_EDIT;
 
        if (tree->edit.textarea == NULL) {
                return;
        }
 
        assert(n != NULL);
 
        /* Get new text length */
        len = textarea_get_text(tree->edit.textarea, NULL, 0);
 
        new_text = malloc(len);
        if (new_text == NULL) {
                /* TODO: don't just silently ignore */
                return;
        }
 
        /* Get the new text from textarea */
        error = textarea_get_text(tree->edit.textarea, new_text, len);
        if (error == -1) {
                /* TODO: don't just silently ignore */
                free(new_text);
                return;
        }
 
        /* Inform the treeview client with change request message */
        msg.data.node_edit.field = tree->edit.field;
        msg.data.node_edit.text = new_text;
 
        switch (n->type) {
        case TREE_NODE_ENTRY:
                tree->callbacks->entry(msg, n->client_data);
                break;
        case TREE_NODE_FOLDER:
                tree->callbacks->folder(msg, n->client_data);
                break;
        case TREE_NODE_ROOT:
                break;
        default:
                break;
        }
 
        /* Finished with the new text */
        free(new_text);
 
        /* Finally, destroy the treeview, and redraw */
        treeview_edit_cancel(tree, true);
}
 
 
/**
 * context for treeview node deletion iterator
 */
struct treeview_node_delete {
        treeview *tree;
        int h_reduction;
        bool user_interaction;
};
 
 
/**
 * Treewalk node callback deleting nodes.
 */
static nserror
treeview_delete_node_walk_cb(treeview_node *n, void *ctx, bool *end)
{
        struct treeview_node_delete *nd = (struct treeview_node_delete *)ctx;
        struct treeview_node_msg msg;
 
        msg.msg = TREE_MSG_NODE_DELETE;
        msg.data.delete.user = nd->user_interaction;
 
        assert(n->children == NULL);
 
        if (treeview_unlink_node(n))
                nd->h_reduction += (n->type == TREE_NODE_ENTRY) ?
                        n->height : tree_g.line_height;
 
        /* Handle any special treatment */
        switch (n->type) {
        case TREE_NODE_ENTRY:
                nd->tree->callbacks->entry(msg, n->client_data);
                break;
 
        case TREE_NODE_FOLDER:
                nd->tree->callbacks->folder(msg, n->client_data);
                break;
 
        case TREE_NODE_ROOT:
                break;
 
        default:
                return NSERROR_BAD_PARAMETER;
        }
 
        /* Cancel any edit of this node */
        if (nd->tree->edit.textarea != NULL &&
            nd->tree->edit.node == n) {
                treeview_edit_cancel(nd->tree, false);
        }
 
        /* Free the node */
        free(n);
 
        return NSERROR_OK;
}
 
 
/**
 * Delete a treeview node
 *
 * Will emit folder or entry deletion msg callback.
 *
 * \note this can be called from inside a treeview_walk fwd callback.
 * For example walking the tree and calling this for any node that's selected.
 *
 * This function does not delete empty nodes, so if TREEVIEW_DEL_EMPTY_DIRS is
 * set, caller must also call treeview_delete_empty.
 *
 * \param tree          Treeview object to delete node from
 * \param n             Node to delete
 * \param interaction   Delete is result of user interaction with treeview
 * \param flags         Treeview node options flags
 * \return NSERROR_OK on success, appropriate error otherwise
 */
static nserror
treeview_delete_node_internal(treeview *tree,
                              treeview_node *n,
                              bool interaction,
                              treeview_node_options_flags flags)
{
        nserror err;
        treeview_node *p = n->parent;
        struct treeview_node_delete nd = {
                .tree = tree,
                .h_reduction = 0,
                .user_interaction = interaction
        };
 
        if (interaction && (tree->flags & TREEVIEW_NO_DELETES)) {
                return NSERROR_OK;
        }
 
        /* Delete any children first */
        err = treeview_walk_internal(tree, n,
                        TREEVIEW_WALK_MODE_LOGICAL_COMPLETE,
                        treeview_delete_node_walk_cb, NULL, &nd);
        if (err != NSERROR_OK) {
                return err;
        }
 
        /* Now delete node */
        if (n == tree->root)
                tree->root = NULL;
        err = treeview_delete_node_walk_cb(n, &nd, false);
        if (err != NSERROR_OK) {
                return err;
        }
 
        n = p;
        /* Reduce ancestor heights */
        while (n != NULL && n->flags & TV_NFLAGS_EXPANDED) {
                n->height -= nd.h_reduction;
                n = n->parent;
        }
 
        /* Inform front end of change in dimensions */
        if (tree->root != NULL && p != NULL && p->flags & TV_NFLAGS_EXPANDED &&
            nd.h_reduction > 0 &&
            !(flags & TREE_OPTION_SUPPRESS_RESIZE)) {
                treeview__cw_update_size(tree, -1,
                                         tree->root->height);
        }
 
        treeview__search_update_display(tree);
 
        return NSERROR_OK;
}
 
 
/**
 * Delete any empty treeview folder nodes
 *
 * \param tree Treeview object to delete empty nodes from
 * \param interaction Delete is result of user interaction with treeview
 * \return NSERROR_OK on success, appropriate error otherwise
 *
 * Note this must not be called within a treeview_walk.  It may delete the
 * walker's 'current' node, making it impossible to move on without invalid
 * reads.
 */
static nserror treeview_delete_empty_nodes(treeview *tree, bool interaction)
{
        treeview_node *node, *child, *parent, *next_sibling, *p;
        bool abort = false;
        nserror err;
        struct treeview_node_delete nd = {
                .tree = tree,
                .h_reduction = 0,
                .user_interaction = interaction
        };
 
        assert(tree != NULL);
        assert(tree->root != NULL);
 
        node = tree->root;
        parent = node->parent;
        next_sibling = node->next_sib;
        child = (node->flags & TV_NFLAGS_EXPANDED) ? node->children : NULL;
 
        while (node != NULL) {
 
                if (child != NULL) {
                        /* Down to children */
                        node = child;
                } else {
                        /* No children.  As long as we're not at the root,
                         * go to next sibling if present, or nearest ancestor
                         * with a next sibling. */
 
                        while (node->parent != NULL &&
                               next_sibling == NULL) {
                                if (node->type == TREE_NODE_FOLDER &&
                                    node->children == NULL) {
                                        /* Delete node */
                                        p = node->parent;
                                        err = treeview_delete_node_walk_cb(
                                                node, &nd, &abort);
                                        if (err != NSERROR_OK) {
                                                return err;
                                        }
 
                                        /* Reduce ancestor heights */
                                        while (p != NULL &&
                                               p->flags &
                                               TV_NFLAGS_EXPANDED) {
                                                p->height -= nd.h_reduction;
                                                p = p->parent;
                                        }
                                        nd.h_reduction = 0;
                                }
                                node = parent;
                                parent = node->parent;
                                next_sibling = node->next_sib;
                        }
 
                        if (node->parent == NULL)
                                break;
 
                        if (node->type == TREE_NODE_FOLDER &&
                            node->children == NULL) {
                                /* Delete node */
                                p = node->parent;
                                err = treeview_delete_node_walk_cb(
                                        node, &nd, &abort);
                                if (err != NSERROR_OK) {
                                        return err;
                                }
 
                                /* Reduce ancestor heights */
                                while (p != NULL &&
                                       p->flags & TV_NFLAGS_EXPANDED) {
                                        p->height -= nd.h_reduction;
                                        p = p->parent;
                                }
                                nd.h_reduction = 0;
                        }
                        node = next_sibling;
                }
 
                assert(node != NULL);
                assert(node->parent != NULL);
 
                parent = node->parent;
                next_sibling = node->next_sib;
                child = (node->flags & TV_NFLAGS_EXPANDED) ?
                        node->children : NULL;
        }
 
        return NSERROR_OK;
}
 
 
/* Exported interface, documented in treeview.h */
nserror
treeview_delete_node(treeview *tree,
                     treeview_node *n,
                     treeview_node_options_flags flags)
{
        nserror err;
        struct rect r;
        bool visible;
 
        assert(tree != NULL);
        assert(n != NULL);
        assert(n->parent != NULL);
 
        visible = n->parent->flags & TV_NFLAGS_EXPANDED;
 
        r.y0 = treeview_node_y(tree, n);
        r.y1 = tree->root->height;
 
        err = treeview_delete_node_internal(tree, n, false, flags);
        if (err != NSERROR_OK)
                return err;
 
        if (tree->flags & TREEVIEW_DEL_EMPTY_DIRS) {
                int h = tree->root->height;
                /* Delete any empty nodes */
                err = treeview_delete_empty_nodes(tree, false);
                if (err != NSERROR_OK)
                        return err;
 
                /* Inform front end of change in dimensions */
                if (tree->root->height != h) {
                        r.y0 = 0;
                        if (!(flags & TREE_OPTION_SUPPRESS_RESIZE)) {
                                treeview__cw_update_size(tree, -1,
                                                         tree->root->height);
                        }
                }
        }
 
        /* Redraw */
        if (visible && !(flags & TREE_OPTION_SUPPRESS_REDRAW)) {
                r.x0 = 0;
                r.x1 = REDRAW_MAX;
                treeview__cw_invalidate_area(tree, &r);
        }
 
        return NSERROR_OK;
}
 
 
/**
 * Helper to create a textarea.
 *
 * \param[in] tree         The treeview we're creating the textarea for.
 * \param[in] width        The width of the textarea.
 * \param[in] height       The height of the textarea.
 * \param[in] border       The border colour to use.
 * \param[in] background   The background colour to use.
 * \param[in] foreground   The foreground colour to use.
 * \param[in] text         The text style to use for the text area.
 * \param[in] ta_callback  The textarea callback function to give the textarea.
 * \return the textarea pointer on success, or NULL on failure.
 */
static struct textarea *treeview__create_textarea(
                treeview *tree,
                int width,
                int height,
                colour border,
                colour background,
                colour foreground,
                plot_font_style_t text,
                textarea_client_callback ta_callback)
{
        /* Configure the textarea */
        textarea_flags ta_flags = TEXTAREA_INTERNAL_CARET;
        textarea_setup ta_setup = {
                .text = text,
                .width = width,
                .height = height,
                .pad_top = 0,
                .pad_left = 2,
                .pad_right = 2,
                .pad_bottom = 0,
                .border_width = 1,
                .border_col = border,
                .selected_bg = foreground,
                .selected_text = background,
        };
 
        ta_setup.text.foreground = foreground;
        ta_setup.text.background = background;
 
        /* Create text area */
        return textarea_create(ta_flags, &ta_setup, ta_callback, tree);
}
 
 
/* Exported interface, documented in treeview.h */
nserror
treeview_create(treeview **tree,
                const struct treeview_callback_table *callbacks,
                int n_fields,
                struct treeview_field_desc fields[],
                const struct core_window_callback_table *cw_t,
                struct core_window *cw,
                treeview_flags flags)
{
        nserror error;
        int i;
 
        assert((cw_t == NULL && cw == NULL) || (cw_t != NULL && cw != NULL));
        assert(callbacks != NULL);
 
        assert(fields != NULL);
        assert(fields[0].flags & TREE_FLAG_DEFAULT);
        assert(fields[n_fields - 1].flags & TREE_FLAG_DEFAULT);
        assert(n_fields >= 2);
 
        *tree = malloc(sizeof(struct treeview));
        if (*tree == NULL) {
                return NSERROR_NOMEM;
        }
 
        (*tree)->fields = malloc(sizeof(struct treeview_field) * n_fields);
        if ((*tree)->fields == NULL) {
                free(*tree);
                return NSERROR_NOMEM;
        }
 
        error = treeview_create_node_root(&((*tree)->root));
        if (error != NSERROR_OK) {
                free((*tree)->fields);
                free(*tree);
                return error;
        }
 
        (*tree)->field_width = 0;
        for (i = 0; i < n_fields; i++) {
                struct treeview_field *f = &((*tree)->fields[i]);
 
                f->flags = fields[i].flags;
                f->field = lwc_string_ref(fields[i].field);
                f->value.data = lwc_string_data(fields[i].field);
                f->value.len = lwc_string_length(fields[i].field);
 
                guit->layout->width(&plot_style_odd.text, f->value.data,
                                    f->value.len, &(f->value.width));
 
                if (f->flags & TREE_FLAG_SHOW_NAME)
                        if ((*tree)->field_width < f->value.width)
                                (*tree)->field_width = f->value.width;
        }
 
        (*tree)->field_width += tree_g.step_width;
 
        (*tree)->callbacks = callbacks;
        (*tree)->n_fields = n_fields - 1;
 
        (*tree)->drag.type = TV_DRAG_NONE;
        (*tree)->drag.start_node = NULL;
        (*tree)->drag.start.x = 0;
        (*tree)->drag.start.y = 0;
        (*tree)->drag.start.node_y = 0;
        (*tree)->drag.start.node_h = 0;
        (*tree)->drag.prev.x = 0;
        (*tree)->drag.prev.y = 0;
        (*tree)->drag.prev.node_y = 0;
        (*tree)->drag.prev.node_h = 0;
 
        (*tree)->move.root = NULL;
        (*tree)->move.target = NULL;
        (*tree)->move.target_pos = TV_TARGET_NONE;
 
        (*tree)->edit.textarea = NULL;
        (*tree)->edit.node = NULL;
 
        if (flags & TREEVIEW_SEARCHABLE) {
                (*tree)->search.textarea = treeview__create_textarea(
                                *tree, 600, tree_g.line_height,
                                nscolours[NSCOLOUR_TEXT_INPUT_BG],
                                nscolours[NSCOLOUR_TEXT_INPUT_BG],
                                nscolours[NSCOLOUR_TEXT_INPUT_FG],
                                plot_style_odd.text,
                                treeview_textarea_search_callback);
                if ((*tree)->search.textarea == NULL) {
                        treeview_destroy(*tree);
                        return NSERROR_NOMEM;
                }
        } else {
                (*tree)->search.textarea = NULL;
        }
        (*tree)->search.active = false;
        (*tree)->search.search = false;
 
        (*tree)->flags = flags;
 
        (*tree)->cw_t = cw_t;
        (*tree)->cw_h = cw;
 
        return NSERROR_OK;
}
 
 
/* Exported interface, documented in treeview.h */
nserror
treeview_cw_attach(treeview *tree,
                   const struct core_window_callback_table *cw_t,
                   struct core_window *cw)
{
        assert(cw_t != NULL);
        assert(cw != NULL);
 
        if (tree->cw_t != NULL || tree->cw_h != NULL) {
                NSLOG(netsurf, INFO, "Treeview already attached.");
                return NSERROR_UNKNOWN;
        }
        tree->cw_t = cw_t;
        tree->cw_h = cw;
 
        return NSERROR_OK;
}
 
 
/* Exported interface, documented in treeview.h */
nserror treeview_cw_detach(treeview *tree)
{
        tree->cw_t = NULL;
        tree->cw_h = NULL;
 
        treeview__search_cancel(tree, true);
 
        return NSERROR_OK;
}
 
 
/* Exported interface, documented in treeview.h */
nserror treeview_destroy(treeview *tree)
{
        int f;
 
        assert(tree != NULL);
 
        if (tree->search.textarea != NULL) {
                tree->search.active = false;
                tree->search.search = false;
                textarea_destroy(tree->search.textarea);
        }
 
        /* Destroy nodes */
        treeview_delete_node_internal(tree, tree->root, false,
                                      TREE_OPTION_SUPPRESS_RESIZE |
                                      TREE_OPTION_SUPPRESS_REDRAW);
 
        /* Destroy feilds */
        for (f = 0; f <= tree->n_fields; f++) {
                lwc_string_unref(tree->fields[f].field);
        }
        free(tree->fields);
 
        /* Free treeview */
        free(tree);
 
        return NSERROR_OK;
}
 
 
/**
 * Expand a treeview's nodes
 *
 * \param tree Treeview object to expand nodes in
 * \param node The node to expand.
 * \return NSERROR_OK on success, appropriate error otherwise.
 */
static nserror
treeview_node_expand_internal(treeview *tree, treeview_node *node)
{
        treeview_node *child;
        struct treeview_node_entry *e;
        int additional_height_folders = 0;
        int additional_height_entries = 0;
        int i;
 
        assert(tree != NULL);
        assert(node != NULL);
 
        if (node->flags & TV_NFLAGS_EXPANDED) {
                /* What madness is this? */
                NSLOG(netsurf, INFO, "Tried to expand an expanded node.");
                return NSERROR_OK;
        }
 
        switch (node->type) {
        case TREE_NODE_FOLDER:
                child = node->children;
                if (child == NULL) {
                        /* Allow expansion of empty folders */
                        break;
                }
 
                do {
                        if (child->text.width == 0) {
                                guit->layout->width(&plot_style_odd.text,
                                                    child->text.data,
                                                    child->text.len,
                                                    &(child->text.width));
                        }
 
                        additional_height_folders += child->height;
 
                        child = child->next_sib;
                } while (child != NULL);
 
                break;
 
        case TREE_NODE_ENTRY:
                assert(node->children == NULL);
 
                e = (struct treeview_node_entry *)node;
 
                for (i = 0; i < tree->n_fields - 1; i++) {
 
                        if (e->fields[i].value.width == 0) {
                                guit->layout->width(&plot_style_odd.text,
                                                    e->fields[i].value.data,
                                                    e->fields[i].value.len,
                                                    &(e->fields[i].value.width));
                        }
 
                        /* Add height for field */
                        additional_height_entries += tree_g.line_height;
                }
 
                break;
 
        case TREE_NODE_ROOT:
        case TREE_NODE_NONE:
                assert(node->type != TREE_NODE_ROOT);
                assert(node->type != TREE_NODE_NONE);
                break;
        }
 
        /* Update the node */
        node->flags |= TV_NFLAGS_EXPANDED;
 
        /* And node heights */
        for (struct treeview_node *n = node;
                        (n != NULL) && (n->flags & TV_NFLAGS_EXPANDED);
                        n = n->parent) {
                n->height += additional_height_entries +
                                additional_height_folders;
        }
 
        if (tree->search.search &&
                        node->type == TREE_NODE_ENTRY &&
                        node->flags & TV_NFLAGS_MATCHED) {
                tree->search.height += additional_height_entries;
        }
 
        /* Inform front end of change in dimensions */
        if (additional_height_entries + additional_height_folders != 0) {
                treeview__cw_update_size(tree, -1,
                                treeview__get_display_height(tree));
        }
 
        return NSERROR_OK;
}
 
 
/* Exported interface, documented in treeview.h */
nserror treeview_node_expand(treeview *tree, treeview_node *node)
{
        nserror res;
 
        res = treeview_node_expand_internal(tree, node);
        NSLOG(netsurf, INFO, "Expanding!");
        if (res == NSERROR_OK) {
                /* expansion was successful, attempt redraw */
                treeview__redraw_from_node(tree, node);
                NSLOG(netsurf, INFO, "Expanded!");
        }
 
        return res;
}
 
 
/**
 * context for treeview contraction callback
 */
struct treeview_contract_data {
        treeview *tree;
        bool only_entries;
};
 
 
/**
 * Treewalk node callback for handling node contraction.
 *
 * \param n node
 * \param ctx contract iterator context
 * \param end flag to end iteration now
 * \return NSERROR_OK on success else appropriate error code
 */
static nserror treeview_node_contract_cb(treeview_node *n, void *ctx, bool *end)
{
        struct treeview_contract_data *data = ctx;
        int h_reduction_folder = 0;
        int h_reduction_entry = 0;
 
        assert(n != NULL);
        assert(n->type != TREE_NODE_ROOT);
 
        n->flags &= ~TV_NFLAGS_SELECTED;
 
        if ((n->flags & TV_NFLAGS_EXPANDED) == false ||
            (n->type == TREE_NODE_FOLDER && data->only_entries)) {
                /* Nothing to do. */
                return NSERROR_OK;
        }
 
 
        switch (n->type) {
        case TREE_NODE_FOLDER:
                h_reduction_folder = n->height - tree_g.line_height;
                break;
 
        case TREE_NODE_ENTRY:
                h_reduction_entry = n->height - tree_g.line_height;
                break;
 
        default:
                break;
        }
 
 
        assert(h_reduction_folder + h_reduction_entry >= 0);
        for (struct treeview_node *node = n;
                        (node != NULL) && (node->flags & TV_NFLAGS_EXPANDED);
                        node = node->parent) {
                node->height -= h_reduction_folder + h_reduction_entry;
        }
 
        if (data->tree->search.search) {
                data->tree->search.height -= h_reduction_entry;
        }
 
        n->flags ^= TV_NFLAGS_EXPANDED;
 
        return NSERROR_OK;
}
 
 
/**
 * Contract a treeview node
 *
 * \param tree Treeview object to contract node in
 * \param node Node to contract
 * \return NSERROR_OK on success, appropriate error otherwise
 */
static nserror
treeview_node_contract_internal(treeview *tree, treeview_node *node)
{
        struct treeview_contract_data data;
        bool selected;
        assert(node != NULL);
 
        if ((node->flags & TV_NFLAGS_EXPANDED) == false) {
                /* What madness is this? */
                NSLOG(netsurf, INFO, "Tried to contract a contracted node.");
                return NSERROR_OK;
        }
 
        data.tree = tree;
        data.only_entries = false;
        selected = node->flags & TV_NFLAGS_SELECTED;
 
        /* Contract children. */
        treeview_walk_internal(tree, node, TREEVIEW_WALK_MODE_LOGICAL_EXPANDED,
                        treeview_node_contract_cb, NULL, &data);
 
        /* Contract node */
        treeview_node_contract_cb(node, &data, false);
 
        if (selected)
                node->flags |= TV_NFLAGS_SELECTED;
 
        /* Inform front end of change in dimensions */
        treeview__cw_update_size(tree, -1, treeview__get_display_height(tree));
 
        return NSERROR_OK;
}
 
 
/* Exported interface, documented in treeview.h */
nserror treeview_node_contract(treeview *tree, treeview_node *node)
{
        nserror res;
 
        assert(tree != NULL);
 
        res = treeview_node_contract_internal(tree, node);
        NSLOG(netsurf, INFO, "Contracting!");
        if (res == NSERROR_OK) {
                /* successful contraction, request redraw */
                treeview__redraw_from_node(tree, node);
                NSLOG(netsurf, INFO, "Contracted!");
        }
 
        return res;
}
 
 
/* Exported interface, documented in treeview.h */
nserror treeview_contract(treeview *tree, bool all)
{
        int search_height = treeview__get_search_height(tree);
        struct treeview_contract_data data;
        bool selected;
        treeview_node *n;
        struct rect r;
 
        assert(tree != NULL);
        assert(tree->root != NULL);
 
        r.x0 = 0;
        r.y0 = 0;
        r.x1 = REDRAW_MAX;
        r.y1 = tree->root->height + search_height;
 
        data.tree = tree;
        data.only_entries = !all;
 
        for (n = tree->root->children; n != NULL; n = n->next_sib) {
                if ((n->flags & TV_NFLAGS_EXPANDED) == false) {
                        continue;
                }
 
                selected = n->flags & TV_NFLAGS_SELECTED;
 
                /* Contract children. */
                treeview_walk_internal(tree, n,
                                TREEVIEW_WALK_MODE_LOGICAL_EXPANDED,
                                treeview_node_contract_cb, NULL, &data);
 
                /* Contract node */
                treeview_node_contract_cb(n, &data, false);
 
                if (selected)
                        n->flags |= TV_NFLAGS_SELECTED;
        }
 
        /* Inform front end of change in dimensions */
        treeview__cw_update_size(tree, -1, tree->root->height);
 
        /* Redraw */
        treeview__cw_invalidate_area(tree, &r);
 
        return NSERROR_OK;
}
 
 
/**
 * context data for treeview expansion
 */
struct treeview_expand_data {
        treeview *tree;
        bool only_folders;
};
 
 
/**
 * Treewalk node callback for handling recursive node expansion.
 *
 * \param n current node
 * \param ctx node expansion context
 * \param skip_children flag to allow children to be skipped
 * \param end flag to allow iteration to be finished early.
 * \return NSERROR_OK on success else error code.
 */
static nserror
treeview_expand_cb(treeview_node *n,
                   void *ctx,
                   bool *skip_children,
                   bool *end)
{
        struct treeview_expand_data *data = ctx;
        nserror err;
 
        assert(n != NULL);
        assert(n->type != TREE_NODE_ROOT);
 
        if (n->flags & TV_NFLAGS_EXPANDED ||
            (data->only_folders && n->type != TREE_NODE_FOLDER)) {
                /* Nothing to do. */
                return NSERROR_OK;
        }
 
        err = treeview_node_expand_internal(data->tree, n);
 
        return err;
}
 
 
/* Exported interface, documented in treeview.h */
nserror treeview_expand(treeview *tree, bool only_folders)
{
        struct treeview_expand_data data;
        nserror res;
        struct rect r;
 
        assert(tree != NULL);
        assert(tree->root != NULL);
 
        data.tree = tree;
        data.only_folders = only_folders;
 
        res = treeview_walk_internal(tree, tree->root,
                        TREEVIEW_WALK_MODE_LOGICAL_COMPLETE,
                        NULL, treeview_expand_cb, &data);
        if (res == NSERROR_OK) {
                /* expansion succeeded, schedule redraw */
 
                r.x0 = 0;
                r.y0 = 0;
                r.x1 = REDRAW_MAX;
                r.y1 = tree->root->height;
 
                treeview__cw_invalidate_area(tree, &r);
        }
        return res;
}
 
 
/**
 * Draw a treeview normally, in tree mode.
 *
 * \param[in]     tree      The treeview we're rendering.
 * \param[in]     x         X coordinate we're rendering the treeview at.
 * \param[in]     y         Y coordinate we're rendering the treeview at.
 * \param[in,out] render_y  Current vertical position in tree, updated on exit.
 * \param[in]     r         Clip rectangle.
 * \param[in]     data      Redraw data for rendering contents.
 * \param[in]     ctx       Current render context.
 */
static void treeview_redraw_tree(
                treeview *tree,
                const int x,
                const int y,
                int *render_y_in_out,
                const struct rect *r,
                struct content_redraw_data *data,
                const struct redraw_context *ctx)
{
        struct treeview_node_style *style = &plot_style_odd;
        enum treeview_resource_id res = TREE_RES_CONTENT;
        int baseline = (tree_g.line_height * 3 + 2) / 4;
        plot_font_style_t *infotext_style;
        treeview_node *root = tree->root;
        treeview_node *node = tree->root;
        int render_y = *render_y_in_out;
        plot_font_style_t *text_style;
        plot_style_t *bg_style;
        int sel_min, sel_max;
        uint32_t count = 0;
        struct rect rect;
        int inset;
        int x0;
 
        if (tree->drag.start.y > tree->drag.prev.y) {
                sel_min = tree->drag.prev.y;
                sel_max = tree->drag.start.y;
        } else {
                sel_min = tree->drag.start.y;
                sel_max = tree->drag.prev.y;
        }
 
        while (node != NULL) {
                struct treeview_node_entry *entry;
                struct bitmap *furniture;
                bool invert_selection;
                treeview_node *next;
                int height;
                int i;
 
                next = (node->flags & TV_NFLAGS_EXPANDED) ?
                        node->children : NULL;
 
                if (next != NULL) {
                        /* down to children */
                        node = next;
                } else {
                        /* No children.  As long as we're not at the root,
                         * go to next sibling if present, or nearest ancestor
                         * with a next sibling. */
 
                        while (node != root &&
                               node->next_sib == NULL) {
                                node = node->parent;
                        }
 
                        if (node == root)
                                break;
 
                        node = node->next_sib;
                }
 
                assert(node != NULL);
                assert(node != root);
                assert(node->type == TREE_NODE_FOLDER ||
                       node->type == TREE_NODE_ENTRY);
 
                count++;
                inset = x + node->inset;
                height = (node->type == TREE_NODE_ENTRY) ? node->height :
                        tree_g.line_height;
 
                if ((render_y + height) < r->y0) {
                        /* This node's line is above clip region */
                        render_y += height;
                        continue;
                }
 
                style = (count & 0x1) ? &plot_style_odd : &plot_style_even;
                if (tree->drag.type == TV_DRAG_SELECTION &&
                    (render_y + height >= sel_min &&
                     render_y < sel_max)) {
                        invert_selection = true;
                } else {
                        invert_selection = false;
                }
                if ((node->flags & TV_NFLAGS_SELECTED && !invert_selection) ||
                    (!(node->flags & TV_NFLAGS_SELECTED) &&
                     invert_selection)) {
                        bg_style = &style->sbg;
                        text_style = &style->stext;
                        infotext_style = &style->sitext;
                        furniture = (node->flags & TV_NFLAGS_EXPANDED) ?
                                style->furn[TREE_FURN_CONTRACT].sel :
                                style->furn[TREE_FURN_EXPAND].sel;
                } else {
                        bg_style = &style->bg;
                        text_style = &style->text;
                        infotext_style = &style->itext;
                        furniture = (node->flags & TV_NFLAGS_EXPANDED) ?
                                style->furn[TREE_FURN_CONTRACT].bmp :
                                style->furn[TREE_FURN_EXPAND].bmp;
                }
 
                /* Render background */
                rect.x0 = r->x0;
                rect.y0 = render_y;
                rect.x1 = r->x1;
                rect.y1 = render_y + height;
                ctx->plot->rectangle(ctx, bg_style, &rect);
 
                /* Render toggle */
                ctx->plot->bitmap(ctx,
                                furniture,
                                inset,
                                render_y + tree_g.line_height / 4,
                                style->furn[TREE_FURN_EXPAND].size,
                                style->furn[TREE_FURN_EXPAND].size,
                                bg_style->fill_colour,
                                BITMAPF_NONE);
 
                /* Render icon */
                if (node->type == TREE_NODE_ENTRY) {
                        res = TREE_RES_CONTENT;
                } else if (node->flags & TV_NFLAGS_SPECIAL) {
                        res = TREE_RES_FOLDER_SPECIAL;
                } else {
                        res = TREE_RES_FOLDER;
                }
 
                if (treeview_res[res].ready) {
                        /* Icon resource is available */
                        data->x = inset + tree_g.step_width;
                        data->y = render_y + ((tree_g.line_height -
                                              treeview_res[res].height + 1) / 2);
                        data->background_colour = bg_style->fill_colour;
 
                        content_redraw(treeview_res[res].c, data, r, ctx);
                }
 
                /* Render text */
                x0 = inset + tree_g.step_width + tree_g.icon_step;
                ctx->plot->text(ctx,
                                text_style,
                                x0, render_y + baseline,
                                node->text.data,
                                node->text.len);
 
                /* Rendered the node */
                render_y += tree_g.line_height;
                if (render_y > r->y1) {
                        /* Passed the bottom of what's in the clip region.
                         * Done. */
                        break;
                }
 
 
                if (node->type != TREE_NODE_ENTRY ||
                    !(node->flags & TV_NFLAGS_EXPANDED))
                        /* Done everything for this node */
                        continue;
 
                /* Render expanded entry fields */
                entry = (struct treeview_node_entry *)node;
                for (i = 0; i < tree->n_fields - 1; i++) {
                        struct treeview_field *ef = &(tree->fields[i + 1]);
 
                        if (ef->flags & TREE_FLAG_SHOW_NAME) {
                                int max_width = tree->field_width;
 
                                ctx->plot->text(ctx,
                                                infotext_style,
                                                x0 + max_width - ef->value.width - tree_g.step_width,
                                                render_y + baseline,
                                                ef->value.data,
                                                ef->value.len);
 
                                ctx->plot->text(ctx,
                                                infotext_style,
                                                x0 + max_width,
                                                render_y + baseline,
                                                entry->fields[i].value.data,
                                                entry->fields[i].value.len);
                        } else {
                                ctx->plot->text(ctx,
                                                infotext_style,
                                                x0, render_y + baseline,
                                                entry->fields[i].value.data,
                                                entry->fields[i].value.len);
                        }
 
                        /* Rendered the expanded entry field */
                        render_y += tree_g.line_height;
                }
 
                /* Finished rendering expanded entry */
 
                if (render_y > r->y1) {
                        /* Passed the bottom of what's in the clip region.
                         * Done. */
                        break;
                }
        }
 
        *render_y_in_out = render_y;
}
 
 
/**
 * Draw a treeview normally, in tree mode.
 *
 * \param[in]     tree      The treeview we're rendering.
 * \param[in]     x         X coordinate we're rendering the treeview at.
 * \param[in]     y         Y coordinate we're rendering the treeview at.
 * \param[in,out] render_y  Current vertical position in tree, updated on exit.
 * \param[in]     r         Clip rectangle.
 * \param[in]     data      Redraw data for rendering contents.
 * \param[in]     ctx       Current render context.
 */
static void treeview_redraw_search(
                treeview *tree,
                const int x,
                const int y,
                int *render_y_in_out,
                const struct rect *r,
                struct content_redraw_data *data,
                const struct redraw_context *ctx)
{
        struct treeview_node_style *style = &plot_style_odd;
        enum treeview_resource_id res = TREE_RES_CONTENT;
        int baseline = (tree_g.line_height * 3 + 2) / 4;
        plot_font_style_t *infotext_style;
        treeview_node *root = tree->root;
        treeview_node *node = tree->root;
        int render_y = *render_y_in_out;
        plot_font_style_t *text_style;
        plot_style_t *bg_style;
        int sel_min, sel_max;
        uint32_t count = 0;
        struct rect rect;
        int inset;
        int x0;
 
        if (tree->drag.start.y > tree->drag.prev.y) {
                sel_min = tree->drag.prev.y;
                sel_max = tree->drag.start.y;
        } else {
                sel_min = tree->drag.start.y;
                sel_max = tree->drag.prev.y;
        }
 
        while (node != NULL) {
                struct treeview_node_entry *entry;
                struct bitmap *furniture;
                bool invert_selection;
                treeview_node *next;
                int height;
                int i;
 
                next = node->children;
 
                if (next != NULL) {
                        /* down to children */
                        node = next;
                } else {
                        /* No children.  As long as we're not at the root,
                         * go to next sibling if present, or nearest ancestor
                         * with a next sibling. */
 
                        while (node != root &&
                               node->next_sib == NULL) {
                                node = node->parent;
                        }
 
                        if (node == root)
                                break;
 
                        node = node->next_sib;
                }
 
                assert(node != NULL);
                assert(node != root);
                assert(node->type == TREE_NODE_FOLDER ||
                       node->type == TREE_NODE_ENTRY);
 
                if (node->type == TREE_NODE_FOLDER ||
                                !(node->flags & TV_NFLAGS_MATCHED)) {
                        continue;
                }
 
                count++;
                inset = x + tree_g.window_padding;
                height = node->height;
 
                if ((render_y + height) < r->y0) {
                        /* This node's line is above clip region */
                        render_y += height;
                        continue;
                }
 
                style = (count & 0x1) ? &plot_style_odd : &plot_style_even;
                if (tree->drag.type == TV_DRAG_SELECTION &&
                    (render_y + height >= sel_min &&
                     render_y < sel_max)) {
                        invert_selection = true;
                } else {
                        invert_selection = false;
                }
                if ((node->flags & TV_NFLAGS_SELECTED && !invert_selection) ||
                    (!(node->flags & TV_NFLAGS_SELECTED) &&
                     invert_selection)) {
                        bg_style = &style->sbg;
                        text_style = &style->stext;
                        infotext_style = &style->sitext;
                        furniture = (node->flags & TV_NFLAGS_EXPANDED) ?
                                style->furn[TREE_FURN_CONTRACT].sel :
                                style->furn[TREE_FURN_EXPAND].sel;
                } else {
                        bg_style = &style->bg;
                        text_style = &style->text;
                        infotext_style = &style->itext;
                        furniture = (node->flags & TV_NFLAGS_EXPANDED) ?
                                style->furn[TREE_FURN_CONTRACT].bmp :
                                style->furn[TREE_FURN_EXPAND].bmp;
                }
 
                /* Render background */
                rect.x0 = r->x0;
                rect.y0 = render_y;
                rect.x1 = r->x1;
                rect.y1 = render_y + height;
                ctx->plot->rectangle(ctx, bg_style, &rect);
 
                /* Render toggle */
                ctx->plot->bitmap(ctx,
                                furniture,
                                inset,
                                render_y + tree_g.line_height / 4,
                                style->furn[TREE_FURN_EXPAND].size,
                                style->furn[TREE_FURN_EXPAND].size,
                                bg_style->fill_colour,
                                BITMAPF_NONE);
 
                /* Render icon */
                if (node->type == TREE_NODE_ENTRY) {
                        res = TREE_RES_CONTENT;
                } else if (node->flags & TV_NFLAGS_SPECIAL) {
                        res = TREE_RES_FOLDER_SPECIAL;
                } else {
                        res = TREE_RES_FOLDER;
                }
 
                if (treeview_res[res].ready) {
                        /* Icon resource is available */
                        data->x = inset + tree_g.step_width;
                        data->y = render_y + ((tree_g.line_height -
                                              treeview_res[res].height + 1) / 2);
                        data->background_colour = bg_style->fill_colour;
 
                        content_redraw(treeview_res[res].c, data, r, ctx);
                }
 
                /* Render text */
                x0 = inset + tree_g.step_width + tree_g.icon_step;
                ctx->plot->text(ctx,
                                text_style,
                                x0, render_y + baseline,
                                node->text.data,
                                node->text.len);
 
                /* Rendered the node */
                render_y += tree_g.line_height;
                if (render_y > r->y1) {
                        /* Passed the bottom of what's in the clip region.
                         * Done. */
                        break;
                }
 
 
                if (node->type != TREE_NODE_ENTRY ||
                    !(node->flags & TV_NFLAGS_EXPANDED))
                        /* Done everything for this node */
                        continue;
 
                /* Render expanded entry fields */
                entry = (struct treeview_node_entry *)node;
                for (i = 0; i < tree->n_fields - 1; i++) {
                        struct treeview_field *ef = &(tree->fields[i + 1]);
 
                        if (ef->flags & TREE_FLAG_SHOW_NAME) {
                                int max_width = tree->field_width;
 
                                ctx->plot->text(ctx,
                                                infotext_style,
                                                x0 + max_width - ef->value.width - tree_g.step_width,
                                                render_y + baseline,
                                                ef->value.data,
                                                ef->value.len);
 
                                ctx->plot->text(ctx,
                                                infotext_style,
                                                x0 + max_width,
                                                render_y + baseline,
                                                entry->fields[i].value.data,
                                                entry->fields[i].value.len);
                        } else {
                                ctx->plot->text(ctx,
                                                infotext_style,
                                                x0, render_y + baseline,
                                                entry->fields[i].value.data,
                                                entry->fields[i].value.len);
                        }
 
                        /* Rendered the expanded entry field */
                        render_y += tree_g.line_height;
                }
 
                /* Finished rendering expanded entry */
 
                if (render_y > r->y1) {
                        /* Passed the bottom of what's in the clip region.
                         * Done. */
                        break;
                }
        }
 
        *render_y_in_out = render_y;
}
 
 
/* Exported interface, documented in treeview.h */
void
treeview_redraw(treeview *tree,
                const int x,
                const int y,
                struct rect *clip,
                const struct redraw_context *ctx)
{
        struct redraw_context new_ctx = *ctx;
        struct content_redraw_data data;
        struct rect r;
        struct rect rect;
        int render_y = y;
 
        assert(tree != NULL);
        assert(tree->root != NULL);
        assert(tree->root->flags & TV_NFLAGS_EXPANDED);
 
        /* Start knockout rendering if it's available for this plotter */
        if (ctx->plot->option_knockout) {
                knockout_plot_start(ctx, &new_ctx);
        }
 
        /* Set up clip rectangle */
        r.x0 = clip->x0 + x;
        r.y0 = clip->y0 + y;
        r.x1 = clip->x1 + x;
        r.y1 = clip->y1 + y;
        new_ctx.plot->clip(&new_ctx, &r);
 
        /* Setup common content redraw data */
        data.width = tree_g.icon_size;
        data.height = tree_g.icon_size;
        data.scale = 1;
        data.repeat_x = false;
        data.repeat_y = false;
 
        if (tree->flags & TREEVIEW_SEARCHABLE) {
                if (render_y < r.y1) {
                        enum treeview_resource_id icon = TREE_RES_SEARCH;
 
                        /* Fill the blank area at the bottom */
                        rect.x0 = r.x0;
                        rect.y0 = render_y;
                        rect.x1 = r.x1;
                        rect.y1 = render_y + tree_g.line_height;
                        new_ctx.plot->rectangle(&new_ctx, &plot_style_even.bg,
                                        &rect);
 
                        if (treeview_res[icon].ready) {
                                /* Icon resource is available */
                                data.x = tree_g.window_padding;
                                data.y = render_y + ((tree_g.line_height -
                                                treeview_res[icon].height + 1) /
                                                2);
                                data.background_colour = plot_style_even.bg.
                                                fill_colour;
 
                                content_redraw(treeview_res[icon].c,
                                                &data, &r, &new_ctx);
                        }
 
                        textarea_redraw(tree->search.textarea,
                                        x + tree_g.window_padding +
                                                        tree_g.icon_step, y,
                                        plot_style_even.bg.fill_colour, 1.0,
                                        &r, &new_ctx);
                }
                render_y += tree_g.line_height;
        }
 
        /* Render the treeview data */
        if (tree->search.search == true) {
                treeview_redraw_search(tree, x, y,
                                &render_y, &r, &data, &new_ctx);
        } else {
                treeview_redraw_tree(tree, x, y,
                                &render_y, &r, &data, &new_ctx);
        }
 
        if (render_y < r.y1) {
                /* Fill the blank area at the bottom */
                rect.x0 = r.x0;
                rect.y0 = render_y;
                rect.x1 = r.x1;
                rect.y1 = r.y1;
                new_ctx.plot->rectangle(&new_ctx, &plot_style_even.bg, &rect);
        }
 
        /* All normal treeview rendering is done; render any overlays */
        if ((tree->move.target_pos != TV_TARGET_NONE) &&
            (treeview_res[TREE_RES_ARROW].ready)) {
                /* Got a MOVE drag; render move indicator arrow */
                data.x = tree->move.target_area.x0 + x;
                data.y = tree->move.target_area.y0 + y;
                data.background_colour = plot_style_even.bg.fill_colour;
 
                content_redraw(treeview_res[TREE_RES_ARROW].c, &data, &r, &new_ctx);
 
        } else if (tree->edit.textarea != NULL) {
                /* Edit in progress; render textarea */
                textarea_redraw(tree->edit.textarea,
                                tree->edit.x + x, tree->edit.y + y,
                                plot_style_even.bg.fill_colour, 1.0,
                                &r, &new_ctx);
        }
 
        /* Rendering complete */
        if (ctx->plot->option_knockout) {
                knockout_plot_end(ctx);
        }
}
 
 
/**
 * context for treeview selection
 */
struct treeview_selection_walk_data {
        enum {
                TREEVIEW_WALK_HAS_SELECTION,
                TREEVIEW_WALK_GET_FIRST_SELECTED,
                TREEVIEW_WALK_CLEAR_SELECTION,
                TREEVIEW_WALK_SELECT_ALL,
                TREEVIEW_WALK_COMMIT_SELECT_DRAG,
                TREEVIEW_WALK_DELETE_SELECTION,
                TREEVIEW_WALK_PROPAGATE_SELECTION,
                TREEVIEW_WALK_YANK_SELECTION,
                TREEVIEW_WALK_COPY_SELECTION
        } purpose;
        union {
                bool has_selection;
                struct {
                        bool required;
                        struct rect *rect;
                } redraw;
                struct {
                        int sel_min;
                        int sel_max;
                } drag;
                struct {
                        treeview_node *prev;
                        treeview_node *fixed;
                } yank;
                struct {
                        treeview_node *n;
                } first;
                struct {
                        char *text;
                        uint32_t len;
                } copy;
        } data;
        int current_y;
        treeview *tree;
};
 
 
/**
 * Treewalk node callback for handling selection related actions.
 *
 * \param n current node
 * \param ctx node selection context
 * \param skip_children flag to allow children to be skipped
 * \param end flag to allow iteration to be finished early.
 * \return NSERROR_OK on success else error code.
 */
static nserror
treeview_node_selection_walk_cb(treeview_node *n,
                                void *ctx,
                                bool *skip_children,
                                bool *end)
{
        struct treeview_selection_walk_data *sw = ctx;
        int height;
        bool changed = false;
        nserror err;
 
        height = (n->type == TREE_NODE_ENTRY) ? n->height : tree_g.line_height;
        sw->current_y += height;
 
        switch (sw->purpose) {
        case TREEVIEW_WALK_HAS_SELECTION:
                if (n->flags & TV_NFLAGS_SELECTED) {
                        sw->data.has_selection = true;
                        *end = true; /* Can abort tree walk */
                        return NSERROR_OK;
                }
                break;
 
        case TREEVIEW_WALK_GET_FIRST_SELECTED:
                if (n->flags & TV_NFLAGS_SELECTED) {
                        sw->data.first.n = n;
                        *end = true; /* Can abort tree walk */
                        return NSERROR_OK;
                }
                break;
 
        case TREEVIEW_WALK_DELETE_SELECTION:
                if (n->flags & TV_NFLAGS_SELECTED) {
                        err = treeview_delete_node_internal(sw->tree, n, true,
                                                            TREE_OPTION_NONE);
                        if (err != NSERROR_OK) {
                                return err;
                        }
                        *skip_children = true;
                        changed = true;
                }
                break;
 
        case TREEVIEW_WALK_PROPAGATE_SELECTION:
                if (n->parent != NULL &&
                    n->parent->flags & TV_NFLAGS_SELECTED &&
                    !(n->flags & TV_NFLAGS_SELECTED)) {
                        n->flags ^= TV_NFLAGS_SELECTED;
                        changed = true;
                }
                break;
 
        case TREEVIEW_WALK_CLEAR_SELECTION:
                if (n->flags & TV_NFLAGS_SELECTED) {
                        n->flags ^= TV_NFLAGS_SELECTED;
                        changed = true;
                }
                break;
 
        case TREEVIEW_WALK_SELECT_ALL:
                if (!(n->flags & TV_NFLAGS_SELECTED)) {
                        n->flags ^= TV_NFLAGS_SELECTED;
                        changed = true;
                }
                break;
 
        case TREEVIEW_WALK_COMMIT_SELECT_DRAG:
                if (sw->current_y >= sw->data.drag.sel_min &&
                    sw->current_y - height <
                    sw->data.drag.sel_max) {
                        n->flags ^= TV_NFLAGS_SELECTED;
                }
                return NSERROR_OK;
 
        case TREEVIEW_WALK_YANK_SELECTION:
                if (n->flags & TV_NFLAGS_SELECTED) {
                        treeview_node *p = n->parent;
                        int h = 0;
 
                        if (n == sw->data.yank.fixed) {
                                break;
                        }
 
                        if (treeview_unlink_node(n))
                                h = n->height;
 
                        /* Reduce ancestor heights */
                        while (p != NULL && p->flags & TV_NFLAGS_EXPANDED) {
                                p->height -= h;
                                p = p->parent;
                        }
                        if (sw->data.yank.prev == NULL) {
                                sw->tree->move.root = n;
                                n->parent = NULL;
                                n->prev_sib = NULL;
                                n->next_sib = NULL;
                        } else {
                                n->parent = NULL;
                                n->prev_sib = sw->data.yank.prev;
                                n->next_sib = NULL;
                                sw->data.yank.prev->next_sib = n;
                        }
                        sw->data.yank.prev = n;
 
                        *skip_children = true;
                }
                break;
 
        case TREEVIEW_WALK_COPY_SELECTION:
                if (n->flags & TV_NFLAGS_SELECTED &&
                    n->type == TREE_NODE_ENTRY) {
                        int i;
                        char *temp;
                        uint32_t len;
                        const char *text;
                        struct treeview_field *ef;
                        struct treeview_text *val;
 
                        for (i = 0; i < sw->tree->n_fields; i++) {
                                ef = &(sw->tree->fields[i]);
 
                                if (!(ef->flags & TREE_FLAG_COPY_TEXT)) {
                                        continue;
                                }
                                val = treeview_get_text_for_field(sw->tree,
                                                                  n, i);
                                text = val->data;
                                len  = val->len;
 
                                temp = realloc(sw->data.copy.text,
                                               sw->data.copy.len + len + 1);
                                if (temp == NULL) {
                                        free(sw->data.copy.text);
                                        sw->data.copy.text = NULL;
                                        sw->data.copy.len = 0;
                                        return NSERROR_NOMEM;
                                }
 
                                if (sw->data.copy.len != 0) {
                                        temp[sw->data.copy.len - 1] = '\n';
                                }
                                memcpy(temp + sw->data.copy.len, text, len);
                                temp[sw->data.copy.len + len] = '\0';
                                sw->data.copy.len += len + 1;
                                sw->data.copy.text = temp;
                        }
                }
                break;
        }
 
        if (changed) {
                if (sw->data.redraw.required == false) {
                        sw->data.redraw.required = true;
                        sw->data.redraw.rect->y0 = sw->current_y - height;
                }
 
                if (sw->current_y > sw->data.redraw.rect->y1) {
                        sw->data.redraw.rect->y1 = sw->current_y;
                }
        }
 
        return NSERROR_OK;
}
 
 
/* Exported interface, documented in treeview.h */
bool treeview_has_selection(treeview *tree)
{
        struct treeview_selection_walk_data sw;
 
        sw.purpose = TREEVIEW_WALK_HAS_SELECTION;
        sw.data.has_selection = false;
 
        treeview_walk_internal(tree, tree->root,
                        TREEVIEW_WALK_MODE_DISPLAY, NULL,
                        treeview_node_selection_walk_cb, &sw);
 
        return sw.data.has_selection;
}
 
 
/**
 * Get first selected node (in any)
 *
 * \param tree Treeview object in which to create folder
 * \return the first selected treeview node, or NULL
 */
static treeview_node * treeview_get_first_selected(treeview *tree)
{
        struct treeview_selection_walk_data sw;
 
        sw.purpose = TREEVIEW_WALK_GET_FIRST_SELECTED;
        sw.data.first.n = NULL;
 
        treeview_walk_internal(tree, tree->root,
                        TREEVIEW_WALK_MODE_DISPLAY, NULL,
                        treeview_node_selection_walk_cb, &sw);
 
        return sw.data.first.n;
}
 
 
/* Exported interface, documented in treeview.h */
enum treeview_node_type treeview_get_selection(treeview *tree,
                                               void **node_data)
{
        treeview_node *n;
 
        assert(tree != NULL);
 
        n = treeview_get_first_selected(tree);
 
        if (n != NULL && n->type & (TREE_NODE_ENTRY | TREE_NODE_FOLDER)) {
                *node_data = n->client_data;
                return n->type;
        }
 
        *node_data = NULL;
        return TREE_NODE_NONE;
}
 
 
/**
 * Clear any selection in a treeview
 *
 * \param tree Treeview object to clear selection in
 * \param rect Redraw rectangle (if redraw required)
 * \return true iff redraw required
 */
static bool treeview_clear_selection(treeview *tree, struct rect *rect)
{
        struct treeview_selection_walk_data sw;
 
        rect->x0 = 0;
        rect->y0 = 0;
        rect->x1 = REDRAW_MAX;
        rect->y1 = 0;
 
        sw.purpose = TREEVIEW_WALK_CLEAR_SELECTION;
        sw.data.redraw.required = false;
        sw.data.redraw.rect = rect;
        sw.current_y = treeview__get_search_height(tree);
 
        treeview_walk_internal(tree, tree->root,
                        TREEVIEW_WALK_MODE_DISPLAY, NULL,
                        treeview_node_selection_walk_cb, &sw);
 
        return sw.data.redraw.required;
}
 
 
/**
 * Select all in a treeview
 *
 * \param tree Treeview object to select all in
 * \param rect Redraw rectangle (if redraw required)
 * \return true iff redraw required
 */
static bool treeview_select_all(treeview *tree, struct rect *rect)
{
        struct treeview_selection_walk_data sw;
 
        rect->x0 = 0;
        rect->y0 = 0;
        rect->x1 = REDRAW_MAX;
        rect->y1 = 0;
 
        sw.purpose = TREEVIEW_WALK_SELECT_ALL;
        sw.data.redraw.required = false;
        sw.data.redraw.rect = rect;
        sw.current_y = treeview__get_search_height(tree);
 
        treeview_walk_internal(tree, tree->root,
                        TREEVIEW_WALK_MODE_DISPLAY, NULL,
                        treeview_node_selection_walk_cb, &sw);
 
        return sw.data.redraw.required;
}
 
 
/**
 * Commit a current selection drag, modifying the node's selection state.
 *
 * \param tree Treeview object to commit drag selection in
 */
static void treeview_commit_selection_drag(treeview *tree)
{
        struct treeview_selection_walk_data sw;
 
        sw.purpose = TREEVIEW_WALK_COMMIT_SELECT_DRAG;
        sw.current_y = treeview__get_search_height(tree);
 
        if (tree->drag.start.y > tree->drag.prev.y) {
                sw.data.drag.sel_min = tree->drag.prev.y;
                sw.data.drag.sel_max = tree->drag.start.y;
        } else {
                sw.data.drag.sel_min = tree->drag.start.y;
                sw.data.drag.sel_max = tree->drag.prev.y;
        }
 
        treeview_walk_internal(tree, tree->root,
                        TREEVIEW_WALK_MODE_DISPLAY, NULL,
                        treeview_node_selection_walk_cb, &sw);
}
 
 
/**
 * Yank a selection to the node move list.
 *
 * \param tree   Treeview object to yank selection from
 * \param fixed  Treeview node that should not be yanked
 */
static void treeview_move_yank_selection(treeview *tree, treeview_node *fixed)
{
        struct treeview_selection_walk_data sw;
 
        sw.purpose = TREEVIEW_WALK_YANK_SELECTION;
        sw.data.yank.fixed = fixed;
        sw.data.yank.prev = NULL;
        sw.tree = tree;
 
        treeview_walk_internal(tree, tree->root,
                        TREEVIEW_WALK_MODE_DISPLAY, NULL,
                        treeview_node_selection_walk_cb, &sw);
}
 
 
/**
 * Copy a selection to the clipboard.
 *
 * \param tree Treeview object to yank selection from
 */
static void treeview_copy_selection(treeview *tree)
{
        struct treeview_selection_walk_data sw;
        nserror err;
 
        sw.purpose = TREEVIEW_WALK_COPY_SELECTION;
        sw.data.copy.text = NULL;
        sw.data.copy.len = 0;
        sw.tree = tree;
 
        err = treeview_walk_internal(tree, tree->root,
                        TREEVIEW_WALK_MODE_DISPLAY, NULL,
                        treeview_node_selection_walk_cb, &sw);
        if (err != NSERROR_OK) {
                return;
        }
 
        if (sw.data.copy.text != NULL) {
                guit->clipboard->set(sw.data.copy.text,
                                     sw.data.copy.len - 1, NULL, 0);
                free(sw.data.copy.text);
        }
}
 
 
/**
 * Delete a selection.
 *
 * \param tree Treeview object to delete selected nodes from
 * \param rect Updated to redraw rectangle
 * \return true iff redraw required.
 */
static bool treeview_delete_selection(treeview *tree, struct rect *rect)
{
        struct treeview_selection_walk_data sw;
 
        assert(tree != NULL);
        assert(tree->root != NULL);
 
        rect->x0 = 0;
        rect->y0 = 0;
        rect->x1 = REDRAW_MAX;
        rect->y1 = treeview__get_display_height(tree);
 
        sw.purpose = TREEVIEW_WALK_DELETE_SELECTION;
        sw.data.redraw.required = false;
        sw.data.redraw.rect = rect;
        sw.current_y = treeview__get_search_height(tree);
        sw.tree = tree;
 
        treeview_walk_internal(tree, tree->root,
                        TREEVIEW_WALK_MODE_DISPLAY, NULL,
                        treeview_node_selection_walk_cb, &sw);
 
        return sw.data.redraw.required;
}
 
 
/**
 * Propagate selection to visible descendants of selected nodes.
 *
 * \param tree Treeview object to propagate selection in
 * \param rect Redraw rectangle (if redraw required)
 * \return true iff redraw required
 */
static bool treeview_propagate_selection(treeview *tree, struct rect *rect)
{
        struct treeview_selection_walk_data sw;
 
        assert(tree != NULL);
        assert(tree->root != NULL);
 
        rect->x0 = 0;
        rect->y0 = 0;
        rect->x1 = REDRAW_MAX;
        rect->y1 = 0;
 
        sw.purpose = TREEVIEW_WALK_PROPAGATE_SELECTION;
        sw.data.redraw.required = false;
        sw.data.redraw.rect = rect;
        sw.current_y = treeview__get_search_height(tree);
        sw.tree = tree;
 
        treeview_walk_internal(tree, tree->root,
                        TREEVIEW_WALK_MODE_DISPLAY, NULL,
                        treeview_node_selection_walk_cb, &sw);
 
        return sw.data.redraw.required;
}
 
 
/**
 * Move a selection according to the current move drag.
 *
 * \param tree Treeview object to move selected nodes in
 * \param rect Redraw rectangle
 * \return NSERROR_OK on success else appropriate error code
 */
static nserror treeview_move_selection(treeview *tree, struct rect *rect)
{
        treeview_node *node, *next, *parent;
        treeview_node *relation;
        enum treeview_relationship relationship;
        int height;
 
        assert(tree != NULL);
        assert(tree->root != NULL);
        assert(tree->root->children != NULL);
        assert(tree->move.target_pos != TV_TARGET_NONE);
 
        height = tree->root->height;
 
        /* Identify target location */
        switch (tree->move.target_pos) {
        case TV_TARGET_ABOVE:
                if (tree->move.target == NULL) {
                        /* Target: After last child of root */
                        relation = tree->root->children;
                        while (relation->next_sib != NULL) {
                                relation = relation->next_sib;
                        }
                        relationship = TREE_REL_NEXT_SIBLING;
 
                } else if (tree->move.target->prev_sib != NULL) {
                        /* Target: After previous sibling */
                        relation = tree->move.target->prev_sib;
                        relationship = TREE_REL_NEXT_SIBLING;
 
                } else {
                        /* Target: Target: First child of parent */
                        assert(tree->move.target->parent != NULL);
                        relation = tree->move.target->parent;
                        relationship = TREE_REL_FIRST_CHILD;
                }
                break;
 
        case TV_TARGET_INSIDE:
                assert(tree->move.target != NULL);
                relation = tree->move.target;
                relationship = TREE_REL_FIRST_CHILD;
                break;
 
        case TV_TARGET_BELOW:
                assert(tree->move.target != NULL);
                relation = tree->move.target;
                relationship = TREE_REL_NEXT_SIBLING;
                break;
 
        default:
                NSLOG(netsurf, INFO, "Bad drop target for move.");
                return NSERROR_BAD_PARAMETER;
        }
 
        if (relationship == TREE_REL_FIRST_CHILD) {
                parent = relation;
        } else {
                parent = relation->parent;
        }
 
        /* Move all selected nodes from treeview to tree->move.root */
        treeview_move_yank_selection(tree, relation);
 
        /* Move all nodes on tree->move.root to target location */
        for (node = tree->move.root; node != NULL; node = next) {
                next = node->next_sib;
 
                if (node == relation) {
                        continue;
                }
 
                if (!(parent->flags & TV_NFLAGS_EXPANDED)) {
                        if (node->flags & TV_NFLAGS_EXPANDED)
                                treeview_node_contract_internal(tree, node);
                        node->flags &= ~TV_NFLAGS_SELECTED;
                }
 
                treeview_insert_node(tree, node, relation, relationship);
 
                relation = node;
                relationship = TREE_REL_NEXT_SIBLING;
        }
        tree->move.root = NULL;
 
        /* Tell window, if height has changed */
        if (height != tree->root->height)
                treeview__cw_update_size(tree, -1, tree->root->height);
 
        /* TODO: Deal with redraw area properly */
        rect->x0 = 0;
        rect->y0 = 0;
        rect->x1 = REDRAW_MAX;
        rect->y1 = REDRAW_MAX;
 
        return NSERROR_OK;
}
 
 
/**
 * context for treeview launch action
 */
struct treeview_launch_walk_data {
        int selected_depth;
        treeview *tree;
};
 
 
/**
 * Treewalk node walk backward callback for tracking folder selection.
 */
static nserror
treeview_node_launch_walk_bwd_cb(treeview_node *n, void *ctx, bool *end)
{
        struct treeview_launch_walk_data *lw = ctx;
 
        if (n->type == TREE_NODE_FOLDER && n->flags == TV_NFLAGS_SELECTED) {
                lw->selected_depth--;
        }
 
        return NSERROR_OK;
}
 
 
/**
 * Treewalk node walk forward callback for launching nodes.
 *
 * \param n current node
 * \param ctx node launch context
 * \param skip_children flag to allow children to be skipped
 * \param end flag to allow iteration to be finished early.
 * \return NSERROR_OK on success else error code.
 */
static nserror
treeview_node_launch_walk_fwd_cb(treeview_node *n,
                                 void *ctx,
                                 bool *skip_children,
                                 bool *end)
{
        struct treeview_launch_walk_data *lw = ctx;
        nserror ret = NSERROR_OK;
 
        if (n->type == TREE_NODE_FOLDER && n->flags & TV_NFLAGS_SELECTED) {
                lw->selected_depth++;
 
        } else if (n->type == TREE_NODE_ENTRY &&
                   (n->flags & TV_NFLAGS_SELECTED ||
                    lw->selected_depth > 0)) {
                struct treeview_node_msg msg;
                msg.msg = TREE_MSG_NODE_LAUNCH;
                msg.data.node_launch.mouse = BROWSER_MOUSE_HOVER;
                ret = lw->tree->callbacks->entry(msg, n->client_data);
        }
 
        return ret;
}
 
 
/**
 * Launch a selection.
 *
 * \note Selected entries are launched. Entries that are descendants
 *        of selected folders are also launched.
 *
 * \param tree Treeview object to launch selected nodes in
 * \return NSERROR_OK on success, appropriate error otherwise
 */
static nserror treeview_launch_selection(treeview *tree)
{
        struct treeview_launch_walk_data lw;
 
        assert(tree != NULL);
        assert(tree->root != NULL);
 
        lw.selected_depth = 0;
        lw.tree = tree;
 
        return treeview_walk_internal(tree, tree->root,
                        TREEVIEW_WALK_MODE_LOGICAL_COMPLETE,
                        treeview_node_launch_walk_bwd_cb,
                        treeview_node_launch_walk_fwd_cb, &lw);
}
 
 
/* Exported interface, documented in treeview.h */
nserror
treeview_get_relation(treeview *tree,
                      treeview_node **relation,
                      enum treeview_relationship *rel,
                      bool at_y,
                      int y)
{
        treeview_node *n;
 
        assert(tree != NULL);
 
        if (at_y) {
                n = treeview_y_node(tree, y);
 
        } else {
                n = treeview_get_first_selected(tree);
        }
 
        if (n != NULL && n->parent != NULL) {
                if (n == n->parent->children) {
                        /* First child */
                        *relation = n->parent;
                        *rel = TREE_REL_FIRST_CHILD;
                } else {
                        /* Not first child */
                        *relation = n->prev_sib;
                        *rel = TREE_REL_NEXT_SIBLING;
                }
        } else {
                if (tree->root->children == NULL) {
                        /* First child of root */
                        *relation = tree->root;
                        *rel = TREE_REL_FIRST_CHILD;
                } else {
                        /* Last child of root */
                        n = tree->root->children;
                        while (n->next_sib != NULL)
                                n = n->next_sib;
                        *relation = n;
                        *rel = TREE_REL_NEXT_SIBLING;
                }
        }
 
        return NSERROR_OK;
}
 
 
/**
 * context for treeview keyboard action
 */
struct treeview_nav_state {
        treeview *tree;
        treeview_node *prev;
        treeview_node *curr;
        treeview_node *next;
        treeview_node *last;
        int n_selected;
        int prev_n_selected;
};
 
 
/**
 * Treewalk node callback for handling mouse action.
 *
 * \param node current node
 * \param ctx node context
 * \param skip_children flag to allow children to be skipped
 * \param end flag to allow iteration to be finished early.
 * \return NSERROR_OK on success else error code.
 */
static nserror
treeview_node_nav_cb(treeview_node *node,
                     void *ctx,
                     bool *skip_children,
                     bool *end)
{
        struct treeview_nav_state *ns = ctx;
 
        if (node == ns->tree->root)
                return NSERROR_OK;
 
        if (node->flags & TV_NFLAGS_SELECTED) {
                ns->n_selected++;
                if (ns->curr == NULL) {
                        ns->curr = node;
                }
 
        } else {
                if (ns->n_selected == 0) {
                        ns->prev = node;
 
                } else if (ns->prev_n_selected < ns->n_selected) {
                        ns->next = node;
                        ns->prev_n_selected = ns->n_selected;
                }
        }
        ns->last = node;
 
        return NSERROR_OK;
}
 
 
/**
 * Handle keyboard navigation.
 *
 * \note Selected entries are launched.
 *       Entries that are descendants of selected folders are also launched.
 *
 * \param tree Treeview object to launch selected nodes in
 * \param key The ucs4 character codepoint
 * \param rect Updated to redraw rectangle
 * \return true if treeview needs redraw, false otherwise
 */
static bool
treeview_keyboard_navigation(treeview *tree, uint32_t key, struct rect *rect)
{
        struct treeview_nav_state ns = {
                .tree = tree,
                .prev = NULL,
                .curr = NULL,
                .next = NULL,
                .last = NULL,
                .n_selected = 0,
                .prev_n_selected = 0
        };
        int search_height = treeview__get_search_height(tree);
        int h = treeview__get_display_height(tree) + search_height;
        bool redraw = false;
        struct treeview_node *scroll_to_node = NULL;
 
        /* Fill out the nav. state struct, by examining the current selection
         * state */
        treeview_walk_internal(tree, tree->root,
                        TREEVIEW_WALK_MODE_DISPLAY, NULL,
                        treeview_node_nav_cb, &ns);
 
        scroll_to_node = ns.curr;
 
        if (tree->search.search == false) {
                if (ns.next == NULL)
                        ns.next = tree->root->children;
                if (ns.prev == NULL)
                        ns.prev = ns.last;
        }
 
        /* Clear any existing selection */
        redraw = treeview_clear_selection(tree, rect);
 
        switch (key) {
        case NS_KEY_LEFT:
                if (tree->search.search == true) {
                        break;
                }
                if (ns.curr != NULL &&
                    ns.curr->parent != NULL &&
                    ns.curr->parent->type != TREE_NODE_ROOT) {
                        /* Step to parent */
                        ns.curr->parent->flags |= TV_NFLAGS_SELECTED;
                        scroll_to_node = ns.curr->parent;
 
                } else if (ns.curr != NULL && tree->root->children != NULL) {
                        /* Select first node in tree */
                        tree->root->children->flags |= TV_NFLAGS_SELECTED;
                        scroll_to_node = tree->root->children;
                }
                break;
 
        case NS_KEY_RIGHT:
                if (ns.curr != NULL) {
                        if (!(ns.curr->flags & TV_NFLAGS_EXPANDED)) {
                                /* Toggle node to expanded */
                                treeview_node_expand_internal(tree, ns.curr);
                                if (ns.curr->children != NULL) {
                                        /* Step to first child */
                                        ns.curr->children->flags |=
                                                TV_NFLAGS_SELECTED;
                                        scroll_to_node = ns.curr->children;
                                } else {
                                        /* Retain current node selection */
                                        ns.curr->flags |= TV_NFLAGS_SELECTED;
                                }
                        } else {
                                /* Toggle node to contracted */
                                treeview_node_contract_internal(tree, ns.curr);
                                /* Retain current node selection */
                                ns.curr->flags |= TV_NFLAGS_SELECTED;
                        }
 
                } else if (ns.curr != NULL) {
                        /* Retain current node selection */
                        ns.curr->flags |= TV_NFLAGS_SELECTED;
                }
                break;
 
        case NS_KEY_UP:
                if (ns.prev != NULL) {
                        /* Step to previous node */
                        ns.prev->flags |= TV_NFLAGS_SELECTED;
                        scroll_to_node = ns.prev;
                }
                break;
 
        case NS_KEY_DOWN:
                if (ns.next != NULL) {
                        /* Step to next node */
                        ns.next->flags |= TV_NFLAGS_SELECTED;
                        scroll_to_node = ns.next;
                }
                break;
 
        default:
                break;
        }
 
        treeview__cw_scroll_to_node(tree, scroll_to_node);
 
        /* TODO: Deal with redraw area properly */
        rect->x0 = 0;
        rect->y0 = 0;
        rect->x1 = REDRAW_MAX;
        if (treeview__get_display_height(tree) + search_height > h)
                rect->y1 = treeview__get_display_height(tree) + search_height;
        else
                rect->y1 = h;
        redraw = true;
 
        return redraw;
}
 
 
/* Exported interface, documented in treeview.h */
bool treeview_keypress(treeview *tree, uint32_t key)
{
        struct rect r;  /**< Redraw rectangle */
        bool redraw = false;
 
        assert(tree != NULL);
 
        /* Pass to any textarea, if editing in progress */
        if (tree->edit.textarea != NULL) {
                switch (key) {
                case NS_KEY_ESCAPE:
                        treeview_edit_cancel(tree, true);
                        return true;
                case NS_KEY_NL:
                case NS_KEY_CR:
                        treeview_edit_done(tree);
                        return true;
                default:
                        return textarea_keypress(tree->edit.textarea, key);
                }
        } else if (tree->search.active == true) {
                switch (key) {
                case NS_KEY_ESCAPE:
                        treeview__search_cancel(tree, false);
                        return true;
                case NS_KEY_NL:
                case NS_KEY_CR:
                        return true;
                default:
                        return textarea_keypress(tree->search.textarea, key);
                }
        }
 
        /* Keypress to be handled by treeview */
        switch (key) {
        case NS_KEY_SELECT_ALL:
                redraw = treeview_select_all(tree, &r);
                break;
        case NS_KEY_COPY_SELECTION:
                treeview_copy_selection(tree);
                break;
        case NS_KEY_DELETE_LEFT:
        case NS_KEY_DELETE_RIGHT:
                redraw = treeview_delete_selection(tree, &r);
 
                if (tree->flags & TREEVIEW_DEL_EMPTY_DIRS) {
                        int h = tree->root->height;
                        /* Delete any empty nodes */
                        treeview_delete_empty_nodes(tree, false);
 
                        /* Inform front end of change in dimensions */
                        if (tree->root->height != h) {
                                r.y0 = 0;
                                treeview__cw_update_size(tree, -1,
                                                         tree->root->height);
                        }
                }
                break;
        case NS_KEY_CR:
        case NS_KEY_NL:
                treeview_launch_selection(tree);
                break;
        case NS_KEY_ESCAPE:
        case NS_KEY_CLEAR_SELECTION:
                redraw = treeview_clear_selection(tree, &r);
                break;
        case NS_KEY_LEFT:
        case NS_KEY_RIGHT:
        case NS_KEY_UP:
        case NS_KEY_DOWN:
                redraw = treeview_keyboard_navigation(tree, key, &r);
                break;
        default:
                return false;
        }
 
        if (redraw) {
                treeview__cw_invalidate_area(tree, &r);
        }
 
        return true;
}
 
 
/**
 * Set the drag&drop drop indicator
 *
 * \param tree          Treeview object to set node indicator in
 * \param need_redraw   True iff we already have a redraw region
 * \param target        The treeview node with mouse pointer over it
 * \param node_height   The height of node
 * \param node_y        The Y coord of the top of target node
 * \param mouse_y       Y coord of mouse position
 * \param rect          Redraw rectangle (if redraw required)
 * \return true iff redraw required
 */
static bool
treeview_set_move_indicator(treeview *tree,
                            bool need_redraw,
                            treeview_node *target,
                            int node_height,
                            int node_y,
                            int mouse_y,
                            struct rect *rect)
{
        treeview_node *orig = target;
        enum treeview_target_pos target_pos;
        int mouse_pos = mouse_y - node_y;
        int x;
 
        assert(tree != NULL);
        assert(tree->root != NULL);
        assert(tree->root->children != NULL);
        assert(target != NULL);
 
        if (target->flags & TV_NFLAGS_SELECTED) {
                /* Find top selected ancestor */
                while (target->parent &&
                       target->parent->flags & TV_NFLAGS_SELECTED) {
                        target = target->parent;
                }
 
                /* Find top adjacent selected sibling */
                while (target->prev_sib &&
                       target->prev_sib->flags & TV_NFLAGS_SELECTED) {
                        target = target->prev_sib;
                }
                target_pos = TV_TARGET_ABOVE;
 
        } else switch (target->type) {
                case TREE_NODE_FOLDER:
                        if (mouse_pos <= node_height / 4) {
                                target_pos = TV_TARGET_ABOVE;
                        } else if (mouse_pos <= (3 * node_height) / 4 ||
                                   target->flags & TV_NFLAGS_EXPANDED) {
                                target_pos = TV_TARGET_INSIDE;
                        } else {
                                target_pos = TV_TARGET_BELOW;
                        }
                        break;
 
                case TREE_NODE_ENTRY:
                        if (mouse_pos <= node_height / 2) {
                                target_pos = TV_TARGET_ABOVE;
                        } else {
                                target_pos = TV_TARGET_BELOW;
                        }
                        break;
 
                default:
                        assert(target->type != TREE_NODE_ROOT);
                        return false;
                }
 
        if (target_pos == tree->move.target_pos &&
            target == tree->move.target) {
                /* No change */
                return need_redraw;
        }
 
        if (tree->move.target_pos != TV_TARGET_NONE) {
                /* Need to clear old indicator position */
                if (need_redraw) {
                        if (rect->x0 > tree->move.target_area.x0)
                                rect->x0 = tree->move.target_area.x0;
                        if (tree->move.target_area.x1 > rect->x1)
                                rect->x1 = tree->move.target_area.x1;
                        if (rect->y0 > tree->move.target_area.y0)
                                rect->y0 = tree->move.target_area.y0;
                        if (tree->move.target_area.y1 > rect->y1)
                                rect->y1 = tree->move.target_area.y1;
                } else {
                        *rect = tree->move.target_area;
                        need_redraw = true;
                }
        }
 
        /* Offset for ABOVE / BELOW */
        if (target_pos == TV_TARGET_ABOVE) {
                if (target != orig) {
                        node_y = treeview_node_y(tree, target);
                }
                node_y -= (tree_g.line_height + 1) / 2;
        } else if (target_pos == TV_TARGET_BELOW) {
                node_y += node_height - (tree_g.line_height + 1) / 2;
        }
 
        /* Oftsets are all relative to centred (INSIDE) */
        node_y += (tree_g.line_height -
                   treeview_res[TREE_RES_ARROW].height + 1) / 2;
 
        x = target->inset + tree_g.move_offset;
 
        /* Update target details */
        tree->move.target = target;
        tree->move.target_pos = target_pos;
        tree->move.target_area.x0 = x;
        tree->move.target_area.y0 = node_y;
        tree->move.target_area.x1 = tree_g.icon_size + x;
        tree->move.target_area.y1 = tree_g.icon_size + node_y;
 
        if (target_pos != TV_TARGET_NONE) {
                /* Need to draw new indicator position */
                if (need_redraw) {
                        if (rect->x0 > tree->move.target_area.x0)
                                rect->x0 = tree->move.target_area.x0;
                        if (tree->move.target_area.x1 > rect->x1)
                                rect->x1 = tree->move.target_area.x1;
                        if (rect->y0 > tree->move.target_area.y0)
                                rect->y0 = tree->move.target_area.y0;
                        if (tree->move.target_area.y1 > rect->y1)
                                rect->y1 = tree->move.target_area.y1;
                } else {
                        *rect = tree->move.target_area;
                        need_redraw = true;
                }
        }
 
        return need_redraw;
}
 
 
/**
 * Callback for textarea_create, in desktop/treeview.h
 *
 * \param data treeview context
 * \param msg textarea message
 */
static void treeview_textarea_callback(void *data, struct textarea_msg *msg)
{
        treeview *tree = data;
        struct rect *r;
 
        switch (msg->type) {
        case TEXTAREA_MSG_DRAG_REPORT:
                if (msg->data.drag == TEXTAREA_DRAG_NONE) {
                        /* Textarea drag finished */
                        tree->drag.type = TV_DRAG_NONE;
                } else {
                        /* Textarea drag started */
                        tree->drag.type = TV_DRAG_TEXTAREA;
                }
                treeview__cw_drag_status(tree,
                                treeview__get_cw_drag_type(tree));
                break;
 
        case TEXTAREA_MSG_REDRAW_REQUEST:
                r = &msg->data.redraw;
                r->x0 += tree->edit.x;
                r->y0 += tree->edit.y;
                r->x1 += tree->edit.x;
                r->y1 += tree->edit.y;
 
                /* Redraw the textarea */
                treeview__cw_invalidate_area(tree, r);
                break;
 
        default:
                break;
        }
}
 
 
/**
 * Start edit of node field, at given y-coord, if editable
 *
 * \param tree Treeview object to consider editing in
 * \param n The treeview node to try editing
 * \param node_y The Y coord of the top of n
 * \param mouse_x X coord of mouse position
 * \param mouse_y Y coord of mouse position
 * \param rect Redraw rectangle (if redraw required)
 * \return true iff redraw required
 */
static bool
treeview_edit_node_at_point(treeview *tree,
                            treeview_node *n,
                            int node_y,
                            int mouse_x,
                            int mouse_y,
                            struct rect *rect)
{
        struct treeview_text *field_data = NULL;
        struct treeview_field *ef, *field_desc = NULL;
        int pos = node_y + tree_g.line_height;
        int field_y = node_y;
        int field_x;
        int width, height;
        bool success;
 
        /* If the main field is editable, make field_data point to it */
        if (n->type == TREE_NODE_ENTRY)
                ef = &(tree->fields[0]);
        else
                ef = &(tree->fields[tree->n_fields]);
        if (ef->flags & TREE_FLAG_ALLOW_EDIT) {
                field_data = &n->text;
                field_desc = ef;
                field_y = node_y;
        }
 
        /* Check for editable entry fields */
        if (n->type == TREE_NODE_ENTRY && n->height != tree_g.line_height) {
                struct treeview_node_entry *e = (struct treeview_node_entry *)n;
                int i;
 
                for (i = 0; i < tree->n_fields - 1; i++) {
                        if (mouse_y <= pos)
                                continue;
 
                        ef = &(tree->fields[i + 1]);
                        pos += tree_g.line_height;
                        if (mouse_y <= pos && (ef->flags &
                                               TREE_FLAG_ALLOW_EDIT)) {
                                field_data = &e->fields[i].value;
                                field_desc = ef;
                                field_y = pos - tree_g.line_height;
                        }
                }
        }
 
        if (field_data == NULL || field_desc == NULL) {
                /* No editable field */
                return false;
        }
 
        /* Get window width/height */
        treeview__cw_get_window_dimensions(tree, &width, &height);
 
        /* Calculate textarea width/height */
        field_x = n->inset + tree_g.step_width + tree_g.icon_step - 3;
        width -= field_x;
        height = tree_g.line_height;
 
        /* Create text area */
        tree->edit.textarea = treeview__create_textarea(tree, width, height,
                        0x000000, 0xffffff, 0x000000, plot_style_odd.text,
                        treeview_textarea_callback);
        if (tree->edit.textarea == NULL) {
                return false;
        }
 
        success = textarea_set_text(tree->edit.textarea, field_data->data);
        if (!success) {
                textarea_destroy(tree->edit.textarea);
                return false;
        }
 
        tree->edit.node = n;
        tree->edit.field = field_desc->field;
 
        /* Position the caret */
        mouse_x -= field_x;
        if (mouse_x < 0)
                mouse_x = 0;
        else if (mouse_x >= width)
                mouse_x = width - 1;
 
        textarea_mouse_action(tree->edit.textarea,
                              BROWSER_MOUSE_PRESS_1 | BROWSER_MOUSE_CLICK_1,
                              mouse_x, tree_g.line_height / 2);
 
        /* Position the textarea */
        tree->edit.x = field_x;
        tree->edit.y = field_y;
        tree->edit.w = width;
        tree->edit.h = height;
 
        /* Setup redraw rectangle */
        if (rect->x0 > field_x)
                rect->x0 = field_x;
        if (rect->y0 > field_y)
                rect->y0 = field_y;
        if (rect->x1 < field_x + width)
                rect->x1 = field_x + width;
        if (rect->y1 < field_y + height)
                rect->y1 = field_y + height;
 
        return true;
}
 
 
/* Exported interface, documented in treeview.h */
void treeview_edit_selection(treeview *tree)
{
        struct rect rect;
        treeview_node *n;
        bool redraw;
        int y;
 
        assert(tree != NULL);
        assert(tree->root != NULL);
 
        /* Get first selected node */
        n = treeview_get_first_selected(tree);
 
        if (n == NULL)
                return;
 
        /* Get node's y-position */
        y = treeview_node_y(tree, n);
 
        /* Edit node at y */
        redraw = treeview_edit_node_at_point(tree, n, y,
                                             0, y + tree_g.line_height / 2, &rect);
 
        if (redraw == false)
                return;
 
        /* Redraw */
        rect.x0 = 0;
        rect.y0 = y;
        rect.x1 = REDRAW_MAX;
        rect.y1 = y + tree_g.line_height;
        treeview__cw_invalidate_area(tree, &rect);
}
 
 
/**
 * context for treeview mouse handling
 */
struct treeview_mouse_action {
        treeview *tree;
        browser_mouse_state mouse;
        int x;
        int y;
        int current_y;  /* Y coordinate value of top of current node */
        int search_height;
};
 
 
/**
 * Treewalk node callback for handling mouse action.
 *
 * \param node current node
 * \param ctx node context
 * \param skip_children flag to allow children to be skipped
 * \param end flag to allow iteration to be finished early.
 * \return NSERROR_OK on success else error code.
 */
static nserror
treeview_node_mouse_action_cb(treeview_node *node,
                              void *ctx,
                              bool *skip_children,
                              bool *end)
{
        struct treeview_mouse_action *ma = ctx;
        struct rect r;
        bool redraw = false;
        bool click;
        int height;
        enum {
                TV_NODE_ACTION_NONE             = 0,
                TV_NODE_ACTION_SELECTION        = (1 << 0)
        } action = TV_NODE_ACTION_NONE;
        enum treeview_node_part part = TV_NODE_PART_NONE;
        nserror err;
 
        r.x0 = 0;
        r.x1 = REDRAW_MAX;
 
        height = (node->type == TREE_NODE_ENTRY) ? node->height :
                tree_g.line_height;
 
        /* Skip line if we've not reached mouse y */
        if (ma->y > ma->current_y + height) {
                ma->current_y += height;
                return NSERROR_OK; /* Don't want to abort tree walk */
        }
 
        /* Find where the mouse is */
        if (ma->y <= ma->current_y + tree_g.line_height) {
                int inset = node->inset;
                if (ma->tree->search.search == true) {
                        inset = tree_g.window_padding;
                }
                if (ma->x >= inset - 1 &&
                                ma->x < inset + tree_g.step_width) {
                        /* Over expansion toggle */
                        part = TV_NODE_PART_TOGGLE;
 
                } else if (ma->x >= inset + tree_g.step_width &&
                                ma->x < inset + tree_g.step_width +
                                tree_g.icon_step + node->text.width) {
                        /* On node */
                        part = TV_NODE_PART_ON_NODE;
                }
        } else if (node->type == TREE_NODE_ENTRY &&
                   height > tree_g.line_height) {
                /* Expanded entries */
                int x = node->inset + tree_g.step_width + tree_g.icon_step;
                int y = ma->current_y + tree_g.line_height;
                int i;
                struct treeview_node_entry *entry =
                        (struct treeview_node_entry *)node;
                for (i = 0; i < ma->tree->n_fields - 1; i++) {
                        struct treeview_field *ef = &(ma->tree->fields[i + 1]);
 
                        if (ma->y > y + tree_g.line_height) {
                                y += tree_g.line_height;
                                continue;
                        }
 
                        if (ef->flags & TREE_FLAG_SHOW_NAME) {
                                int max_width = ma->tree->field_width;
 
                                if (ma->x >= x + max_width - ef->value.width -
                                    tree_g.step_width &&
                                    ma->x < x + max_width -
                                    tree_g.step_width) {
                                        /* On a field name */
                                        part = TV_NODE_PART_ON_NODE;
 
                                } else if (ma->x >= x + max_width &&
                                           ma->x < x + max_width +
                                           entry->fields[i].value.width) {
                                        /* On a field value */
                                        part = TV_NODE_PART_ON_NODE;
                                }
                        } else {
                                if (ma->x >= x && ma->x < x +
                                    entry->fields[i].value.width) {
                                        /* On a field value */
                                        part = TV_NODE_PART_ON_NODE;
                                }
                        }
 
                        break;
                }
        }
 
        /* Record what position / part a drag started on */
        if (ma->mouse & (BROWSER_MOUSE_PRESS_1 | BROWSER_MOUSE_PRESS_2) &&
            ma->tree->drag.type == TV_DRAG_NONE) {
                ma->tree->drag.selected = node->flags & TV_NFLAGS_SELECTED;
                ma->tree->drag.start_node = node;
                ma->tree->drag.part = part;
                ma->tree->drag.start.x = ma->x;
                ma->tree->drag.start.y = ma->y;
                ma->tree->drag.start.node_y = ma->current_y;
                ma->tree->drag.start.node_h = height;
 
                ma->tree->drag.prev.x = ma->x;
                ma->tree->drag.prev.y = ma->y;
                ma->tree->drag.prev.node_y = ma->current_y;
                ma->tree->drag.prev.node_h = height;
        }
 
        /* Handle drag start */
        if (ma->tree->drag.type == TV_DRAG_NONE) {
                if (ma->mouse & BROWSER_MOUSE_DRAG_1 &&
                    ma->tree->drag.selected == false &&
                    ma->tree->drag.part == TV_NODE_PART_NONE) {
                        ma->tree->drag.type = TV_DRAG_SELECTION;
                        treeview__cw_drag_status(ma->tree,
                                                 CORE_WINDOW_DRAG_SELECTION);
 
                } else if (ma->tree->search.search == false &&
                           !(ma->tree->flags & TREEVIEW_NO_MOVES) &&
                           ma->mouse & BROWSER_MOUSE_DRAG_1 &&
                           (ma->tree->drag.selected == true ||
                            ma->tree->drag.part == TV_NODE_PART_ON_NODE)) {
                        ma->tree->drag.type = TV_DRAG_MOVE;
                        treeview__cw_drag_status(ma->tree,
                                                 CORE_WINDOW_DRAG_MOVE);
                        redraw |= treeview_propagate_selection(ma->tree, &r);
 
                } else if (ma->mouse & BROWSER_MOUSE_DRAG_2) {
                        ma->tree->drag.type = TV_DRAG_SELECTION;
                        treeview__cw_drag_status(ma->tree,
                                                 CORE_WINDOW_DRAG_SELECTION);
                }
 
                if (ma->tree->drag.start_node != NULL &&
                    ma->tree->drag.type == TV_DRAG_SELECTION) {
                        ma->tree->drag.start_node->flags ^= TV_NFLAGS_SELECTED;
                }
        }
 
        /* Handle active drags */
        switch (ma->tree->drag.type) {
        case TV_DRAG_SELECTION:
        {
                int curr_y1 = ma->current_y + height;
                int prev_y1 = ma->tree->drag.prev.node_y +
                        ma->tree->drag.prev.node_h;
 
                r.y0 = (ma->current_y < ma->tree->drag.prev.node_y) ?
                        ma->current_y : ma->tree->drag.prev.node_y;
                r.y1 = (curr_y1 > prev_y1) ? curr_y1 : prev_y1;
 
                redraw = true;
 
                ma->tree->drag.prev.x = ma->x;
                ma->tree->drag.prev.y = ma->y;
                ma->tree->drag.prev.node_y = ma->current_y;
                ma->tree->drag.prev.node_h = height;
        }
                break;
 
        case TV_DRAG_MOVE:
                redraw |= treeview_set_move_indicator(ma->tree, redraw,
                                                      node, height,
                                                      ma->current_y, ma->y, &r);
                break;
 
        default:
                break;
        }
 
        click = ma->mouse & (BROWSER_MOUSE_CLICK_1 | BROWSER_MOUSE_CLICK_2);
 
        if (((node->type == TREE_NODE_FOLDER) &&
             (ma->mouse & BROWSER_MOUSE_DOUBLE_CLICK) && click) ||
            (part == TV_NODE_PART_TOGGLE && click)) {
                int h = treeview__get_display_height(ma->tree) +
                                ma->search_height;
 
                /* Clear any existing selection */
                redraw |= treeview_clear_selection(ma->tree, &r);
 
                /* Toggle node expansion */
                if (node->flags & TV_NFLAGS_EXPANDED) {
                        err = treeview_node_contract_internal(ma->tree, node);
                } else {
                        err = treeview_node_expand_internal(ma->tree, node);
                }
                if (err != NSERROR_OK) {
                        return err;
                }
 
                /* Set up redraw */
                if (!redraw || r.y0 > ma->current_y)
                        r.y0 = ma->current_y;
                if (h > treeview__get_display_height(ma->tree) +
                                ma->search_height) {
                        r.y1 = h;
                } else {
                        r.y1 = treeview__get_display_height(ma->tree) +
                                ma->search_height;
                }
                redraw = true;
 
        } else if ((node->type == TREE_NODE_ENTRY) &&
                   (ma->mouse & BROWSER_MOUSE_DOUBLE_CLICK) && click) {
                struct treeview_node_msg msg;
                msg.msg = TREE_MSG_NODE_LAUNCH;
                msg.data.node_launch.mouse = ma->mouse;
 
                /* Clear any existing selection */
                redraw |= treeview_clear_selection(ma->tree, &r);
 
                /* Tell client an entry was launched */
                ma->tree->callbacks->entry(msg, node->client_data);
 
        } else if (ma->mouse & BROWSER_MOUSE_PRESS_2 ||
                   (ma->mouse & BROWSER_MOUSE_PRESS_1 &&
                    ma->mouse & BROWSER_MOUSE_MOD_2)) {
                /* Toggle selection of node */
                action |= TV_NODE_ACTION_SELECTION;
 
        } else if (ma->mouse & BROWSER_MOUSE_CLICK_1 &&
                   ma->mouse &
                   (BROWSER_MOUSE_MOD_1 | BROWSER_MOUSE_MOD_3) &&
                   part != TV_NODE_PART_TOGGLE) {
 
                /* Clear any existing selection */
                redraw |= treeview_clear_selection(ma->tree, &r);
 
                /* Edit node */
                redraw |= treeview_edit_node_at_point(ma->tree, node,
                                                      ma->current_y, ma->x,
                                                      ma->y, &r);
 
        } else if (ma->mouse & BROWSER_MOUSE_PRESS_1 &&
                   !(ma->mouse &
                     (BROWSER_MOUSE_MOD_1 | BROWSER_MOUSE_MOD_3)) &&
                   !(node->flags & TV_NFLAGS_SELECTED) &&
                   part != TV_NODE_PART_TOGGLE) {
                /* Clear any existing selection */
                redraw |= treeview_clear_selection(ma->tree, &r);
 
                /* Select node */
                action |= TV_NODE_ACTION_SELECTION;
 
        }
 
        if (action & TV_NODE_ACTION_SELECTION) {
                /* Handle change in selection */
                node->flags ^= TV_NFLAGS_SELECTED;
 
                /* Redraw */
                if (!redraw) {
                        r.y0 = ma->current_y;
                        r.y1 = ma->current_y + height;
                        redraw = true;
                } else {
                        if (r.y0 > ma->current_y) {
                                r.y0 = ma->current_y;
                        }
                        if (r.y1 < ma->current_y + height) {
                                r.y1 = ma->current_y + height;
                        }
                }
        }
 
        if (redraw) {
                treeview__cw_invalidate_area(ma->tree, &r);
        }
 
        *end = true; /* Reached line with click; stop walking tree */
        return NSERROR_OK;
}
 
 
/* Exported interface, documented in treeview.h */
void
treeview_mouse_action(treeview *tree, browser_mouse_state mouse, int x, int y)
{
        struct rect r;
        bool redraw = false;
        int search_height = treeview__get_search_height(tree);
 
        assert(tree != NULL);
        assert(tree->root != NULL);
 
        /* Not interested in whether mouse leaves window. */
        if (mouse == BROWSER_MOUSE_LEAVE) {
                return;
        }
 
        /* Handle mouse drag captured by textarea */
        if (tree->drag.type == TV_DRAG_TEXTAREA) {
                textarea_mouse_action(tree->edit.textarea, mouse,
                                      x - tree->edit.x, y - tree->edit.y);
                return;
        } else if (tree->drag.type == TV_DRAG_SEARCH) {
                if (tree->search.active == false) {
                        tree->search.active = true;
                        if (treeview_clear_selection(tree, &r)) {
                                treeview__cw_invalidate_area(tree, &r);
                        }
                }
                textarea_mouse_action(tree->search.textarea, mouse,
                                x - tree_g.window_padding - tree_g.icon_size,
                                y);
                return;
        } else if (mouse & (BROWSER_MOUSE_PRESS_1 | BROWSER_MOUSE_PRESS_2) &&
                   y < search_height && tree->search.active == false) {
                tree->search.active = true;
                if (treeview_clear_selection(tree, &r)) {
                        treeview__cw_invalidate_area(tree, &r);
                }
                textarea_mouse_action(tree->search.textarea, mouse,
                                x - tree_g.window_padding - tree_g.icon_size,
                                y);
                return;
        } else if (mouse & (BROWSER_MOUSE_PRESS_1 | BROWSER_MOUSE_PRESS_2) &&
                        tree->search.active == true) {
 
                tree->search.active = false;
                textarea_set_caret(tree->search.textarea, -1);
                r.x0 = 0;
                r.y0 = 0;
                r.x1 = REDRAW_MAX;
                r.y1 = tree_g.line_height;
                treeview__cw_invalidate_area(tree, &r);
        }
 
        /* Handle textarea related mouse action */
        if (tree->edit.textarea != NULL) {
                int ta_x = x - tree->edit.x;
                int ta_y = y - tree->edit.y;
 
                if (ta_x > 0 && ta_x < tree->edit.w &&
                    ta_y > 0 && ta_y < tree->edit.h) {
                        /* Inside textarea */
                        textarea_mouse_action(tree->edit.textarea, mouse,
                                              ta_x, ta_y);
                        return;
 
                } else if (mouse != BROWSER_MOUSE_HOVER) {
                        /* Action outside textarea */
                        treeview_edit_cancel(tree, true);
                }
        }
 
        /* Handle drag ends */
        if (mouse == BROWSER_MOUSE_HOVER) {
                switch (tree->drag.type) {
                case TV_DRAG_SELECTION:
                        treeview_commit_selection_drag(tree);
                        tree->drag.type = TV_DRAG_NONE;
                        tree->drag.start_node = NULL;
 
                        treeview__cw_drag_status(tree, CORE_WINDOW_DRAG_NONE);
                        return;
                case TV_DRAG_MOVE:
                        treeview_move_selection(tree, &r);
                        tree->drag.type = TV_DRAG_NONE;
                        tree->drag.start_node = NULL;
 
                        tree->move.target = NULL;
                        tree->move.target_pos = TV_TARGET_NONE;
 
                        treeview__cw_drag_status(tree, CORE_WINDOW_DRAG_NONE);
                        treeview__cw_invalidate_area(tree, &r);
                        return;
                default:
                        /* No drag to end */
                        break;
                }
        }
 
        if (y > treeview__get_display_height(tree) + search_height) {
                /* Below tree */
 
                r.x0 = 0;
                r.x1 = REDRAW_MAX;
 
                /* Record what position / part a drag started on */
                if (mouse & (BROWSER_MOUSE_PRESS_1 | BROWSER_MOUSE_PRESS_2) &&
                    tree->drag.type == TV_DRAG_NONE) {
                        tree->drag.selected = false;
                        tree->drag.start_node = NULL;
                        tree->drag.part = TV_NODE_PART_NONE;
                        tree->drag.start.x = x;
                        tree->drag.start.y = y;
                        tree->drag.start.node_y = tree->root->height;
                        tree->drag.start.node_h = 0;
 
                        tree->drag.prev.x = x;
                        tree->drag.prev.y = y;
                        tree->drag.prev.node_y = tree->root->height;
                        tree->drag.prev.node_h = 0;
                }
 
                /* Handle drag start */
                if (tree->drag.type == TV_DRAG_NONE) {
                        if (mouse & BROWSER_MOUSE_DRAG_1 &&
                            tree->drag.selected == false &&
                            tree->drag.part == TV_NODE_PART_NONE) {
                                tree->drag.type = TV_DRAG_SELECTION;
                                treeview__cw_drag_status(tree,
                                                CORE_WINDOW_DRAG_SELECTION);
                        } else if (mouse & BROWSER_MOUSE_DRAG_2) {
                                tree->drag.type = TV_DRAG_SELECTION;
                                treeview__cw_drag_status(tree,
                                                CORE_WINDOW_DRAG_SELECTION);
                        }
 
                        if (tree->drag.start_node != NULL &&
                            tree->drag.type == TV_DRAG_SELECTION) {
                                tree->drag.start_node->flags ^=
                                        TV_NFLAGS_SELECTED;
                        }
                }
 
                /* Handle selection drags */
                if (tree->drag.type == TV_DRAG_SELECTION) {
                        int curr_y1 = tree->root->height;
                        int prev_y1 = tree->drag.prev.node_y +
                                tree->drag.prev.node_h;
 
                        r.y0 = tree->drag.prev.node_y;
                        r.y1 = (curr_y1 > prev_y1) ? curr_y1 : prev_y1;
 
                        redraw = true;
 
                        tree->drag.prev.x = x;
                        tree->drag.prev.y = y;
                        tree->drag.prev.node_y = curr_y1;
                        tree->drag.prev.node_h = 0;
                }
 
                if (mouse & BROWSER_MOUSE_PRESS_1) {
                        /* Clear any existing selection */
                        redraw |= treeview_clear_selection(tree, &r);
                }
 
                if (redraw) {
                        treeview__cw_invalidate_area(tree, &r);
                }
 
        } else {
                /* On tree */
                struct treeview_mouse_action ma = {
                        .tree = tree,
                        .mouse = mouse,
                        .x = x,
                        .y = y,
                        .current_y = search_height,
                        .search_height = search_height,
                };
 
                treeview_walk_internal(tree, tree->root,
                                TREEVIEW_WALK_MODE_DISPLAY, NULL,
                                treeview_node_mouse_action_cb, &ma);
        }
}
 
/* Exported interface, documented in treeview.h */
int treeview_get_height(treeview *tree)
{
        int search_height = treeview__get_search_height(tree);
        int height = treeview__get_display_height(tree);
 
        assert(tree != NULL);
        assert(tree->root != NULL);
 
        treeview__cw_update_size(tree, -1, height);
 
        return height + search_height;
}
 
/* Exported interface, documented in treeview.h */
nserror treeview_set_search_string(
                treeview *tree,
                const char *string)
{
        if (!(tree->flags & TREEVIEW_SEARCHABLE)) {
                return NSERROR_BAD_PARAMETER;
        }
 
        if (string == NULL || strlen(string) == 0) {
                tree->search.active = false;
                tree->search.search = false;
                return treeview__search(tree, "", 0);
        }
 
        tree->search.active = true;
        tree->search.search = true;
        if (!textarea_set_text(tree->search.textarea, string)) {
                return NSERROR_UNKNOWN;
        }
 
        treeview__cw_full_redraw(tree);
 
        return NSERROR_OK;
}
 
/**
 * Initialise the plot styles from CSS system colour values.
 *
 * \param font_pt_size font size to use
 * \return NSERROR_OK on success else appropriate error code
 */
static nserror treeview_init_plot_styles(int font_pt_size)
{
        /* Background colour */
        plot_style_even.bg.stroke_type = PLOT_OP_TYPE_NONE;
        plot_style_even.bg.stroke_width = 0;
        plot_style_even.bg.stroke_colour = 0;
        plot_style_even.bg.fill_type = PLOT_OP_TYPE_SOLID;
        plot_style_even.bg.fill_colour = nscolours[NSCOLOUR_WIN_EVEN_BG];
 
        /* Text colour */
        plot_style_even.text.family = PLOT_FONT_FAMILY_SANS_SERIF;
        plot_style_even.text.size = font_pt_size;
        plot_style_even.text.weight = 400;
        plot_style_even.text.flags = FONTF_NONE;
        plot_style_even.text.foreground = nscolours[NSCOLOUR_WIN_EVEN_FG];
        plot_style_even.text.background = nscolours[NSCOLOUR_WIN_EVEN_BG];
 
        /* Entry field text colour */
        plot_style_even.itext = plot_style_even.text;
        plot_style_even.itext.foreground = nscolours[NSCOLOUR_WIN_EVEN_FG_FADED];
 
        /* Selected background colour */
        plot_style_even.sbg = plot_style_even.bg;
        plot_style_even.sbg.fill_colour = nscolours[NSCOLOUR_SEL_BG];
 
        /* Selected text colour */
        plot_style_even.stext = plot_style_even.text;
        plot_style_even.stext.foreground = nscolours[NSCOLOUR_SEL_FG];
        plot_style_even.stext.background = nscolours[NSCOLOUR_SEL_BG];
 
        /* Selected entry field text colour */
        plot_style_even.sitext = plot_style_even.stext;
        plot_style_even.sitext.foreground = nscolours[NSCOLOUR_SEL_FG_SUBTLE];
 
        /* Odd numbered node styles */
        plot_style_odd.bg = plot_style_even.bg;
        plot_style_odd.bg.fill_colour = nscolours[NSCOLOUR_WIN_ODD_BG];
        plot_style_odd.text = plot_style_even.text;
        plot_style_odd.text.background = plot_style_odd.bg.fill_colour;
        plot_style_odd.itext = plot_style_odd.text;
        plot_style_odd.itext.foreground = nscolours[NSCOLOUR_WIN_EVEN_FG_FADED];
 
        plot_style_odd.sbg = plot_style_even.sbg;
        plot_style_odd.stext = plot_style_even.stext;
        plot_style_odd.sitext = plot_style_even.sitext;
 
        return NSERROR_OK;
}
 
 
/**
 * Callback for hlcache retrieving resources.
 *
 * \param handle content hlcache handle
 * \param event The event that occurred on the content
 * \param pw treeview resource context
 */
static nserror
treeview_res_cb(struct hlcache_handle *handle,
                const hlcache_event *event,
                void *pw)
{
        struct treeview_resource *r = pw;
 
        switch (event->type) {
        case CONTENT_MSG_READY:
        case CONTENT_MSG_DONE:
                r->ready = true;
                r->height = content_get_height(handle);
                break;
 
        default:
                break;
        }
 
        return NSERROR_OK;
}
 
 
/**
 * Fetch content resources used by treeview.
 */
static void treeview_init_resources(void)
{
        int i;
 
        for (i = 0; i < TREE_RES_LAST; i++) {
                nsurl *url;
                treeview_res[i].ready = false;
                treeview_res[i].height = 0;
                if (nsurl_create(treeview_res[i].url, &url) == NSERROR_OK) {
                        hlcache_handle_retrieve(url, 0, NULL, NULL,
                                                treeview_res_cb,
                                                &(treeview_res[i]), NULL,
                                                CONTENT_IMAGE,
                                                &(treeview_res[i].c));
                        nsurl_unref(url);
                }
        }
}
 
 
/**
 * Create a right-pointing anti-aliased triangle bitmap
 *
 * \param bg background colour
 * \param fg foreground colour
 * \param size required bitmap size
 */
static struct bitmap *
treeview_generate_triangle_bitmap(colour bg, colour fg, int size)
{
        struct bitmap *b = NULL;
        int x, y;
        unsigned char *rpos;
        unsigned char *pos;
        size_t stride;
 
        /* Set up required colour graduations.  Ignores screen gamma. */
        colour colour0 = bg;
        colour colour1 = mix_colour(bg, fg, 255 * 3 / 4);
        colour colour2 = blend_colour(bg, fg);
        colour colour3 = mix_colour(bg, fg, 255 * 1 / 4);
        colour colour4 = fg;
 
        /* Create the bitmap */
        b = guit->bitmap->create(size, size, BITMAP_OPAQUE);
        if (b == NULL)
                return NULL;
 
        rpos = guit->bitmap->get_buffer(b);
        stride = guit->bitmap->get_rowstride(b);
 
        /* Draw the triangle */
        for (y = 0; y < size; y++) {
                pos = rpos;
 
                if (y < size / 2) {
                        /* Top half */
                        for (x = 0; x < y * 2; x++) {
                                pos[bitmap_layout.r] = red_from_colour(colour4);
                                pos[bitmap_layout.g] = green_from_colour(colour4);
                                pos[bitmap_layout.b] = blue_from_colour(colour4);
                                pos[bitmap_layout.a] = 0xff;
                                pos += 4;
                        }
                        pos[bitmap_layout.r] = red_from_colour(colour3);
                        pos[bitmap_layout.g] = green_from_colour(colour3);
                        pos[bitmap_layout.b] = blue_from_colour(colour3);
                        pos[bitmap_layout.a] = 0xff;
                        pos += 4;
                        pos[bitmap_layout.r] = red_from_colour(colour1);
                        pos[bitmap_layout.g] = green_from_colour(colour1);
                        pos[bitmap_layout.b] = blue_from_colour(colour1);
                        pos[bitmap_layout.a] = 0xff;
                        pos += 4;
                        for (x = y * 2 + 2; x < size ; x++) {
                                pos[bitmap_layout.r] = red_from_colour(colour0);
                                pos[bitmap_layout.g] = green_from_colour(colour0);
                                pos[bitmap_layout.b] = blue_from_colour(colour0);
                                pos[bitmap_layout.a] = 0xff;
                                pos += 4;
                        }
                } else if ((y == size / 2) && (size & 0x1)) {
                        /* Middle row */
                        for (x = 0; x < size - 1; x++) {
                                pos[bitmap_layout.r] = red_from_colour(colour4);
                                pos[bitmap_layout.g] = green_from_colour(colour4);
                                pos[bitmap_layout.b] = blue_from_colour(colour4);
                                pos[bitmap_layout.a] = 0xff;
                                pos += 4;
                        }
                        pos[bitmap_layout.r] = red_from_colour(colour2);
                        pos[bitmap_layout.g] = green_from_colour(colour2);
                        pos[bitmap_layout.b] = blue_from_colour(colour2);
                        pos[bitmap_layout.a] = 0xff;
                        pos += 4;
                } else {
                        /* Bottom half */
                        for (x = 0; x < (size - y - 1) * 2; x++) {
                                pos[bitmap_layout.r] = red_from_colour(colour4);
                                pos[bitmap_layout.g] = green_from_colour(colour4);
                                pos[bitmap_layout.b] = blue_from_colour(colour4);
                                pos[bitmap_layout.a] = 0xff;
                                pos += 4;
                        }
                        pos[bitmap_layout.r] = red_from_colour(colour3);
                        pos[bitmap_layout.g] = green_from_colour(colour3);
                        pos[bitmap_layout.b] = blue_from_colour(colour3);
                        pos[bitmap_layout.a] = 0xff;
                        pos += 4;
                        pos[bitmap_layout.r] = red_from_colour(colour1);
                        pos[bitmap_layout.g] = green_from_colour(colour1);
                        pos[bitmap_layout.b] = blue_from_colour(colour1);
                        pos[bitmap_layout.a] = 0xff;
                        pos += 4;
                        for (x = (size - y) * 2; x < size ; x++) {
                                pos[bitmap_layout.r] = red_from_colour(colour0);
                                pos[bitmap_layout.g] = green_from_colour(colour0);
                                pos[bitmap_layout.b] = blue_from_colour(colour0);
                                pos[bitmap_layout.a] = 0xff;
                                pos += 4;
                        }
                }
 
                rpos += stride;
        }
 
        guit->bitmap->modified(b);
 
        return b;
}
 
 
/**
 * Create bitmap copy of another bitmap
 *
 * \param orig bitmap to copy
 * \param size required bitmap size
 */
static struct bitmap *
treeview_generate_copy_bitmap(struct bitmap *orig, int size)
{
        struct bitmap *b = NULL;
        unsigned char *data;
        unsigned char *orig_data;
        size_t stride;
 
        if (orig == NULL)
                return NULL;
 
        assert(size == guit->bitmap->get_width(orig));
        assert(size == guit->bitmap->get_height(orig));
 
        /* Create the bitmap */
        b = guit->bitmap->create(size, size, BITMAP_OPAQUE);
        if (b == NULL)
                return NULL;
 
        stride = guit->bitmap->get_rowstride(b);
        assert(stride == guit->bitmap->get_rowstride(orig));
 
        data = guit->bitmap->get_buffer(b);
        orig_data = guit->bitmap->get_buffer(orig);
 
        /* Copy the bitmap */
        memcpy(data, orig_data, stride * size);
 
        guit->bitmap->modified(b);
 
        /* We've not modified the original image, but we called
         * bitmap_get_buffer(), so we need to pair that with a
         * bitmap_modified() call to appease certain front ends. */
        guit->bitmap->modified(orig);
 
        return b;
}
 
 
/**
 * Create bitmap from rotation of another bitmap
 *
 * \param orig bitmap to create rotation of
 * \param size required bitmap size
 */
static struct bitmap *
treeview_generate_rotate_bitmap(struct bitmap *orig, int size)
{
        struct bitmap *b = NULL;
        int x, y;
        unsigned char *rpos;
        unsigned char *pos;
        unsigned char *orig_data;
        unsigned char *orig_pos;
        size_t stride;
 
        if (orig == NULL)
                return NULL;
 
        assert(size == guit->bitmap->get_width(orig));
        assert(size == guit->bitmap->get_height(orig));
 
        /* Create the bitmap */
        b = guit->bitmap->create(size, size, BITMAP_OPAQUE);
        if (b == NULL)
                return NULL;
 
        stride = guit->bitmap->get_rowstride(b);
        assert(stride == guit->bitmap->get_rowstride(orig));
 
        rpos = guit->bitmap->get_buffer(b);
        orig_data = guit->bitmap->get_buffer(orig);
 
        /* Copy the rotated bitmap */
        for (y = 0; y < size; y++) {
                pos = rpos;
 
                for (x = 0; x < size; x++) {
                        orig_pos = orig_data + x * stride + y * 4;
                        *(pos++) = *(orig_pos++);
                        *(pos++) = *(orig_pos++);
                        *(pos++) = *(orig_pos);
                        *(pos++) = 0xff;
 
                }
 
                rpos += stride;
        }
 
        guit->bitmap->modified(b);
 
        /* We've not modified the original image, but we called
         * bitmap_get_buffer(), so we need to pair that with a
         * bitmap_modified() call to appease certain front ends.
         */
        guit->bitmap->modified(orig);
 
        return b;
}
 
 
/**
 * Measures width of characters used to represent treeview furniture.
 *
 * \return NSERROR_OK on success else error code
 */
static nserror treeview_init_furniture(void)
{
        int size = tree_g.line_height / 2;
 
        plot_style_odd.furn[TREE_FURN_EXPAND].size = size;
        plot_style_odd.furn[TREE_FURN_EXPAND].bmp =
                treeview_generate_triangle_bitmap(
                        plot_style_odd.bg.fill_colour,
                        plot_style_odd.itext.foreground, size);
        plot_style_odd.furn[TREE_FURN_EXPAND].sel =
                treeview_generate_triangle_bitmap(
                        plot_style_odd.sbg.fill_colour,
                        plot_style_odd.sitext.foreground, size);
 
        plot_style_even.furn[TREE_FURN_EXPAND].size = size;
        plot_style_even.furn[TREE_FURN_EXPAND].bmp =
                treeview_generate_triangle_bitmap(
                        plot_style_even.bg.fill_colour,
                        plot_style_even.itext.foreground, size);
        plot_style_even.furn[TREE_FURN_EXPAND].sel =
                treeview_generate_copy_bitmap(
                        plot_style_odd.furn[TREE_FURN_EXPAND].sel, size);
 
        plot_style_odd.furn[TREE_FURN_CONTRACT].size = size;
        plot_style_odd.furn[TREE_FURN_CONTRACT].bmp =
                treeview_generate_rotate_bitmap(
                        plot_style_odd.furn[TREE_FURN_EXPAND].bmp, size);
        plot_style_odd.furn[TREE_FURN_CONTRACT].sel =
                treeview_generate_rotate_bitmap(
                        plot_style_odd.furn[TREE_FURN_EXPAND].sel, size);
 
        plot_style_even.furn[TREE_FURN_CONTRACT].size = size;
        plot_style_even.furn[TREE_FURN_CONTRACT].bmp =
                treeview_generate_rotate_bitmap(
                        plot_style_even.furn[TREE_FURN_EXPAND].bmp, size);
        plot_style_even.furn[TREE_FURN_CONTRACT].sel =
                treeview_generate_rotate_bitmap(
                        plot_style_even.furn[TREE_FURN_EXPAND].sel, size);
 
        if (plot_style_odd.furn[TREE_FURN_EXPAND].bmp == NULL ||
            plot_style_odd.furn[TREE_FURN_EXPAND].sel == NULL ||
            plot_style_even.furn[TREE_FURN_EXPAND].bmp == NULL ||
            plot_style_even.furn[TREE_FURN_EXPAND].sel == NULL ||
            plot_style_odd.furn[TREE_FURN_CONTRACT].bmp == NULL ||
            plot_style_odd.furn[TREE_FURN_CONTRACT].sel == NULL ||
            plot_style_even.furn[TREE_FURN_CONTRACT].bmp == NULL ||
            plot_style_even.furn[TREE_FURN_CONTRACT].sel == NULL)
                return NSERROR_NOMEM;
 
        tree_g.furniture_width = size + tree_g.line_height / 4;
 
        return NSERROR_OK;
}
 
 
/* Exported interface, documented in treeview.h */
nserror treeview_init(void)
{
        long long font_px_size;
        long long font_pt_size;
        nserror res;
 
        if (tree_g.initialised > 0) {
                tree_g.initialised++;
                return NSERROR_OK;
        }
 
        NSLOG(netsurf, INFO, "Initialising treeview module");
 
        font_pt_size = nsoption_int(treeview_font_size);
        if (font_pt_size <= 0) {
                font_pt_size = 11 * 10;
        }
 
        font_px_size = (font_pt_size * FIXTOINT(nscss_screen_dpi) /
                        10 + 36) / 72;
        tree_g.line_height = (font_px_size * 8 + 3) / 6;
 
        res = treeview_init_plot_styles(font_pt_size * PLOT_STYLE_SCALE / 10);
        if (res != NSERROR_OK) {
                return res;
        }
 
        treeview_init_resources();
 
        res = treeview_init_furniture();
        if (res != NSERROR_OK) {
                return res;
        }
 
        tree_g.step_width = tree_g.furniture_width;
        tree_g.window_padding = 6;
        tree_g.icon_size = 17;
        tree_g.icon_step = 23;
        tree_g.move_offset = 18;
 
        tree_g.initialised++;
 
        NSLOG(netsurf, INFO, "Initialised treeview module");
 
        return NSERROR_OK;
}
 
 
/* Exported interface, documented in treeview.h */
nserror treeview_fini(void)
{
        int i;
 
        if (tree_g.initialised > 1) {
                tree_g.initialised--;
                return NSERROR_OK;
 
        } else if (tree_g.initialised == 0) {
                NSLOG(netsurf, INFO,
                      "Warning: tried to finalise uninitialised treeview module");
                return NSERROR_OK;
        }
 
        NSLOG(netsurf, INFO, "Finalising treeview module");
 
        for (i = 0; i < TREE_RES_LAST; i++) {
                hlcache_handle_release(treeview_res[i].c);
        }
 
        guit->bitmap->destroy(plot_style_odd.furn[TREE_FURN_EXPAND].bmp);
        guit->bitmap->destroy(plot_style_odd.furn[TREE_FURN_EXPAND].sel);
        guit->bitmap->destroy(plot_style_even.furn[TREE_FURN_EXPAND].bmp);
        guit->bitmap->destroy(plot_style_even.furn[TREE_FURN_EXPAND].sel);
        guit->bitmap->destroy(plot_style_odd.furn[TREE_FURN_CONTRACT].bmp);
        guit->bitmap->destroy(plot_style_odd.furn[TREE_FURN_CONTRACT].sel);
        guit->bitmap->destroy(plot_style_even.furn[TREE_FURN_CONTRACT].bmp);
        guit->bitmap->destroy(plot_style_even.furn[TREE_FURN_CONTRACT].sel);
 
        tree_g.initialised--;
 
        NSLOG(netsurf, INFO, "Finalised treeview module");
 
        return NSERROR_OK;
}