dom_event.c

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/*
 * Copyright 2010 Michael Drake <tlsa@netsurf-browser.org>
 * Copyright 2020 Vincent Sanders <vince@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
 * Implementation of HTML content DOM event handling.
 */
 
#include <string.h>
 
#include "utils/config.h"
#include "utils/utils.h"
#include "utils/corestrings.h"
#include "utils/nsoption.h"
#include "utils/log.h"
#include "utils/ascii.h"
#include "utils/string.h"
#include "utils/nsurl.h"
#include "content/content.h"
#include "javascript/js.h"
 
#include "netsurf/bitmap.h"
 
#include "html/private.h"
#include "html/object.h"
#include "html/css.h"
#include "html/box.h"
#include "html/box_construct.h"
#include "html/form_internal.h"
#include "html/dom_event.h"
 
 
/**
 * process a base element being inserted into the DOM
 *
 * \param htmlc The html content containing the DOM
 * \param node The DOM node being inserted
 * \return NSERROR_OK on success else appropriate error code
 */
static bool html_process_inserted_base(html_content *htmlc, dom_node *node)
{
        dom_exception exc; /* returned by libdom functions */
        dom_string *atr_string;
 
        /* get href attribute if present */
        exc = dom_element_get_attribute(node, corestring_dom_href, &atr_string);
        if ((exc == DOM_NO_ERR) && (atr_string != NULL)) {
                nsurl *url;
                nserror error;
 
                /* get url from string */
                error = nsurl_create(dom_string_data(atr_string), &url);
                dom_string_unref(atr_string);
                if (error == NSERROR_OK) {
                        if (htmlc->base_url != NULL) {
                                nsurl_unref(htmlc->base_url);
                        }
                        htmlc->base_url = url;
                }
        }
 
 
        /* get target attribute if present and not already set */
        if (htmlc->base_target != NULL) {
                return true;
        }
 
        exc = dom_element_get_attribute(node,
                                        corestring_dom_target,
                                        &atr_string);
        if ((exc == DOM_NO_ERR) && (atr_string != NULL)) {
                /* Validation rules from the HTML5 spec for the base element:
                 *  The target must be one of _blank, _self, _parent, or
                 *  _top or any identifier which does not begin with an
                 *  underscore
                 */
                if (*dom_string_data(atr_string) != '_' ||
                                dom_string_caseless_lwc_isequal(atr_string,
                                                corestring_lwc__blank) ||
                                dom_string_caseless_lwc_isequal(atr_string,
                                                corestring_lwc__self) ||
                                dom_string_caseless_lwc_isequal(atr_string,
                                                corestring_lwc__parent) ||
                                dom_string_caseless_lwc_isequal(atr_string,
                                                corestring_lwc__top)) {
                        htmlc->base_target = strdup(dom_string_data(atr_string));
                }
                dom_string_unref(atr_string);
        }
 
        return true;
}
 
 
 
/**
 * Process img element being inserted into the DOM.
 *
 * \param htmlc The html content containing the DOM
 * \param node The DOM node being inserted
 * \return NSERROR_OK on success else appropriate error code
 */
static bool html_process_inserted_img(html_content *htmlc, dom_node *node)
{
        dom_string *src;
        nsurl *url;
        nserror err;
        dom_exception exc;
        bool success;
 
        /* Do nothing if foreground images are disabled */
        if (nsoption_bool(foreground_images) == false) {
                return true;
        }
 
        exc = dom_element_get_attribute(node, corestring_dom_src, &src);
        if (exc != DOM_NO_ERR || src == NULL) {
                return true;
        }
 
        err = nsurl_join(htmlc->base_url, dom_string_data(src), &url);
        if (err != NSERROR_OK) {
                dom_string_unref(src);
                return false;
        }
        dom_string_unref(src);
 
        /* Speculatively fetch the image */
        success = html_fetch_object(htmlc, url, NULL, CONTENT_IMAGE, false);
        nsurl_unref(url);
 
        return success;
}
 
 
/**
 * process a LINK element being inserted into the DOM
 *
 * \note only the http-equiv attribute for refresh is currently considered
 *
 * \param htmlc The html content containing the DOM
 * \param n The DOM node being inserted
 * \return NSERROR_OK on success else appropriate error code
 */
static bool html_process_inserted_link(html_content *c, dom_node *node)
{
        struct content_rfc5988_link link; /* the link added to the content */
        dom_exception exc; /* returned by libdom functions */
        dom_string *atr_string;
        nserror error;
 
        /* Handle stylesheet loading */
        html_css_process_link(c, (dom_node *)node);
 
        /* try Generic link handling */
 
        memset(&link, 0, sizeof(struct content_rfc5988_link));
 
        /* check that the relation exists - w3c spec says must be present */
        exc = dom_element_get_attribute(node, corestring_dom_rel, &atr_string);
        if ((exc != DOM_NO_ERR) || (atr_string == NULL)) {
                return false;
        }
        /* get a lwc string containing the link relation */
        exc = dom_string_intern(atr_string, &link.rel);
        dom_string_unref(atr_string);
        if (exc != DOM_NO_ERR) {
                return false;
        }
 
        /* check that the href exists - w3c spec says must be present */
        exc = dom_element_get_attribute(node, corestring_dom_href, &atr_string);
        if ((exc != DOM_NO_ERR) || (atr_string == NULL)) {
                lwc_string_unref(link.rel);
                return false;
        }
 
        /* get nsurl */
        error = nsurl_join(c->base_url, dom_string_data(atr_string),
                        &link.href);
        dom_string_unref(atr_string);
        if (error != NSERROR_OK) {
                lwc_string_unref(link.rel);
                return false;
        }
 
        /* look for optional properties -- we don't care if internment fails */
 
        exc = dom_element_get_attribute(node,
                        corestring_dom_hreflang, &atr_string);
        if ((exc == DOM_NO_ERR) && (atr_string != NULL)) {
                /* get a lwc string containing the href lang */
                (void)dom_string_intern(atr_string, &link.hreflang);
                dom_string_unref(atr_string);
        }
 
        exc = dom_element_get_attribute(node,
                        corestring_dom_type, &atr_string);
        if ((exc == DOM_NO_ERR) && (atr_string != NULL)) {
                /* get a lwc string containing the type */
                (void)dom_string_intern(atr_string, &link.type);
                dom_string_unref(atr_string);
        }
 
        exc = dom_element_get_attribute(node,
                        corestring_dom_media, &atr_string);
        if ((exc == DOM_NO_ERR) && (atr_string != NULL)) {
                /* get a lwc string containing the media */
                (void)dom_string_intern(atr_string, &link.media);
                dom_string_unref(atr_string);
        }
 
        exc = dom_element_get_attribute(node,
                        corestring_dom_sizes, &atr_string);
        if ((exc == DOM_NO_ERR) && (atr_string != NULL)) {
                /* get a lwc string containing the sizes */
                (void)dom_string_intern(atr_string, &link.sizes);
                dom_string_unref(atr_string);
        }
 
        /* add to content */
        content__add_rfc5988_link(&c->base, &link);
 
        if (link.sizes != NULL)
                lwc_string_unref(link.sizes);
        if (link.media != NULL)
                lwc_string_unref(link.media);
        if (link.type != NULL)
                lwc_string_unref(link.type);
        if (link.hreflang != NULL)
                lwc_string_unref(link.hreflang);
 
        nsurl_unref(link.href);
        lwc_string_unref(link.rel);
 
        return true;
}
 
 
/* handler for a SCRIPT which has been added to a tree */
static void
dom_SCRIPT_showed_up(html_content *htmlc, dom_html_script_element *script)
{
        dom_exception exc;
        dom_html_script_element_flags flags;
        dom_hubbub_error res;
        bool within;
 
        if (!htmlc->enable_scripting) {
                NSLOG(netsurf, INFO, "Encountered a script, but scripting is off, ignoring");
                return;
        }
 
        NSLOG(netsurf, DEEPDEBUG, "Encountered a script, node %p showed up", script);
 
        exc = dom_html_script_element_get_flags(script, &flags);
        if (exc != DOM_NO_ERR) {
                NSLOG(netsurf, DEEPDEBUG, "Unable to retrieve flags, giving up");
                return;
        }
 
        if (flags & DOM_HTML_SCRIPT_ELEMENT_FLAG_PARSER_INSERTED) {
                NSLOG(netsurf, DEBUG, "Script was parser inserted, skipping");
                return;
        }
 
        exc = dom_node_contains(htmlc->document, script, &within);
        if (exc != DOM_NO_ERR) {
                NSLOG(netsurf, DEBUG, "Unable to determine if script was within document, ignoring");
                return;
        }
 
        if (!within) {
                NSLOG(netsurf, DEBUG, "Script was not within the document, ignoring for now");
                return;
        }
 
        res = html_process_script(htmlc, (dom_node *) script);
        if (res == DOM_HUBBUB_OK) {
                NSLOG(netsurf, DEEPDEBUG, "Inserted script has finished running");
        } else {
                if (res == (DOM_HUBBUB_HUBBUB_ERR | HUBBUB_PAUSED)) {
                        NSLOG(netsurf, DEEPDEBUG, "Inserted script has launced asynchronously");
                } else {
                        NSLOG(netsurf, DEEPDEBUG, "Failure starting script");
                }
        }
}
 
 
/**
 * process a META element being inserted into the DOM
 *
 * \note only the http-equiv attribute for refresh is currently considered
 *
 * \param htmlc The html content containing the DOM
 * \param n The DOM node being inserted
 * \return NSERROR_OK on success else appropriate error code
 */
static nserror html_process_inserted_meta(html_content *c, dom_node *n)
{
        union content_msg_data msg_data;
        const char *url, *end, *refresh = NULL;
        char *new_url;
        char quote = '\0';
        dom_string *equiv, *content;
        dom_exception exc;
        nsurl *nsurl;
        nserror error = NSERROR_OK;
 
        if (c->refresh) {
                /* refresh already delt with */
                return NSERROR_OK;
        }
 
        exc = dom_element_get_attribute(n, corestring_dom_http_equiv, &equiv);
        if (exc != DOM_NO_ERR) {
                return NSERROR_DOM;
        }
 
        if (equiv == NULL) {
                return NSERROR_OK;
        }
 
        if (!dom_string_caseless_lwc_isequal(equiv, corestring_lwc_refresh)) {
                dom_string_unref(equiv);
                return NSERROR_OK;
        }
 
        dom_string_unref(equiv);
 
        exc = dom_element_get_attribute(n, corestring_dom_content, &content);
        if (exc != DOM_NO_ERR) {
                return NSERROR_DOM;
        }
 
        if (content == NULL) {
                return NSERROR_OK;
        }
 
        end = dom_string_data(content) + dom_string_byte_length(content);
 
        /* content  := *LWS intpart fracpart? *LWS [';' *LWS *1url *LWS]
         * intpart  := 1*DIGIT
         * fracpart := 1*('.' | DIGIT)
         * url      := "url" *LWS '=' *LWS (url-nq | url-sq | url-dq)
         * url-nq   := *urlchar
         * url-sq   := "'" *(urlchar | '"') "'"
         * url-dq   := '"' *(urlchar | "'") '"'
         * urlchar  := [#x9#x21#x23-#x26#x28-#x7E] | nonascii
         * nonascii := [#x80-#xD7FF#xE000-#xFFFD#x10000-#x10FFFF]
         */
 
        url = dom_string_data(content);
 
        /* *LWS */
        while (url < end && ascii_is_space(*url)) {
                url++;
        }
 
        /* intpart */
        if (url == end || (*url < '0' || '9' < *url)) {
                /* Empty content, or invalid timeval */
                dom_string_unref(content);
                return NSERROR_OK;
        }
 
        msg_data.delay = (int) strtol(url, &new_url, 10);
        /* a very small delay and self-referencing URL can cause a loop
         * that grinds machines to a halt. To prevent this we set a
         * minimum refresh delay of 1s. */
        if (msg_data.delay < 1) {
                msg_data.delay = 1;
        }
 
        url = new_url;
 
        /* fracpart? (ignored, as delay is integer only) */
        while (url < end && (('0' <= *url && *url <= '9') ||
                        *url == '.')) {
                url++;
        }
 
        /* *LWS */
        while (url < end && ascii_is_space(*url)) {
                url++;
        }
 
        /* ';' */
        if (url < end && *url == ';')
                url++;
 
        /* *LWS */
        while (url < end && ascii_is_space(*url)) {
                url++;
        }
 
        if (url == end) {
                /* Just delay specified, so refresh current page */
                dom_string_unref(content);
 
                c->base.refresh = nsurl_ref(content_get_url(&c->base));
 
                content_broadcast(&c->base, CONTENT_MSG_REFRESH, &msg_data);
 
                return NSERROR_OK;
        }
 
        /* "url" */
        if (url <= end - 3) {
                if (strncasecmp(url, "url", 3) == 0) {
                        url += 3;
                } else {
                        /* Unexpected input, ignore this header */
                        dom_string_unref(content);
                        return NSERROR_OK;
                }
        } else {
                /* Insufficient input, ignore this header */
                dom_string_unref(content);
                return NSERROR_OK;
        }
 
        /* *LWS */
        while (url < end && ascii_is_space(*url)) {
                url++;
        }
 
        /* '=' */
        if (url < end) {
                if (*url == '=') {
                        url++;
                } else {
                        /* Unexpected input, ignore this header */
                        dom_string_unref(content);
                        return NSERROR_OK;
                }
        } else {
                /* Insufficient input, ignore this header */
                dom_string_unref(content);
                return NSERROR_OK;
        }
 
        /* *LWS */
        while (url < end && ascii_is_space(*url)) {
                url++;
        }
 
        /* '"' or "'" */
        if (url < end && (*url == '"' || *url == '\'')) {
                quote = *url;
                url++;
        }
 
        /* Start of URL */
        refresh = url;
 
        if (quote != 0) {
                /* url-sq | url-dq */
                while (url < end && *url != quote)
                        url++;
        } else {
                /* url-nq */
                while (url < end && !ascii_is_space(*url))
                        url++;
        }
 
        /* '"' or "'" or *LWS (we don't care) */
        if (url > refresh) {
                /* There's a URL */
                new_url = strndup(refresh, url - refresh);
                if (new_url == NULL) {
                        dom_string_unref(content);
                        return NSERROR_NOMEM;
                }
 
                error = nsurl_join(c->base_url, new_url, &nsurl);
                if (error == NSERROR_OK) {
                        /* broadcast valid refresh url */
 
                        c->base.refresh = nsurl;
 
                        content_broadcast(&c->base,
                                          CONTENT_MSG_REFRESH,
                                          &msg_data);
                        c->refresh = true;
                }
 
                free(new_url);
 
        }
 
        dom_string_unref(content);
 
        return error;
}
 
 
/**
 * Process title element being inserted into the DOM.
 *
 * https://html.spec.whatwg.org/multipage/semantics.html#the-title-element
 *
 * \param htmlc The html content containing the DOM
 * \param node The DOM node being inserted
 * \return NSERROR_OK on success else appropriate error code
 */
static nserror html_process_inserted_title(html_content *htmlc, dom_node *node)
{
        if (htmlc->title == NULL) {
                /* only the first title is considered */
                htmlc->title = dom_node_ref(node);
        }
        return NSERROR_OK;
}
 
 
/** process title node */
static bool html_process_title(html_content *c, dom_node *node)
{
        dom_exception exc; /* returned by libdom functions */
        dom_string *title;
        char *title_str;
        bool success;
 
        exc = dom_node_get_text_content(node, &title);
        if ((exc != DOM_NO_ERR) || (title == NULL)) {
                return false;
        }
 
        title_str = squash_whitespace(dom_string_data(title));
        dom_string_unref(title);
 
        if (title_str == NULL) {
                return false;
        }
 
        success = content__set_title(&c->base, title_str);
 
        free(title_str);
 
        return success;
}
 
 
/**
 * Deal with input elements being modified by resyncing their gadget
 * if they have one.
 */
static void html_texty_element_update(html_content *htmlc, dom_node *node)
{
        struct box *box = box_for_node(node);
        if (box == NULL) {
                return; /* No Box (yet?) so no gadget to update */
        }
        if (box->gadget == NULL) {
                return; /* No gadget yet (under construction perhaps?) */
        }
        form_gadget_sync_with_dom(box->gadget);
        /* And schedule a redraw for the box */
        html__redraw_a_box(htmlc, box);
}
 
 
/**
 * callback for DOMNodeInserted end type
 */
static void
dom_default_action_DOMNodeInserted_cb(struct dom_event *evt, void *pw)
{
        dom_event_target *node;
        dom_node_type type;
        dom_exception exc;
        html_content *htmlc = pw;
 
        exc = dom_event_get_target(evt, &node);
        if ((exc != DOM_NO_ERR) || (node == NULL)) {
                /* failed to obtain the event target node */
                return;
        }
 
        exc = dom_node_get_node_type(node, &type);
        if ((exc == DOM_NO_ERR) && (type == DOM_ELEMENT_NODE)) {
                /* an element node has been inserted */
                dom_html_element_type tag_type;
 
                exc = dom_html_element_get_tag_type(node, &tag_type);
                if (exc != DOM_NO_ERR) {
                        tag_type = DOM_HTML_ELEMENT_TYPE__UNKNOWN;
                }
 
                switch (tag_type) {
                case DOM_HTML_ELEMENT_TYPE_BASE:
                        html_process_inserted_base(htmlc, (dom_node *)node);
                        break;
 
                case DOM_HTML_ELEMENT_TYPE_IMG:
                        html_process_inserted_img(htmlc, (dom_node *)node);
                        break;
 
                case DOM_HTML_ELEMENT_TYPE_LINK:
                        html_process_inserted_link(htmlc, (dom_node *)node);
                        break;
 
                case DOM_HTML_ELEMENT_TYPE_META:
                        html_process_inserted_meta(htmlc, (dom_node *)node);
                        break;
 
                case DOM_HTML_ELEMENT_TYPE_STYLE:
                        if (nsoption_bool(author_level_css)) {
                                html_css_process_style(htmlc, (dom_node *)node);
                        }
                        break;
 
                case DOM_HTML_ELEMENT_TYPE_SCRIPT:
                        dom_SCRIPT_showed_up(htmlc,
                                             (dom_html_script_element *)node);
                        break;
 
                case DOM_HTML_ELEMENT_TYPE_TITLE:
                        html_process_inserted_title(htmlc, (dom_node *)node);
                        break;
 
                default:
                        break;
                }
 
                if (htmlc->enable_scripting) {
                        /* ensure javascript context is available */
                        if (htmlc->jsthread == NULL) {
                                union content_msg_data msg_data;
 
                                msg_data.jsthread = &htmlc->jsthread;
                                content_broadcast(&htmlc->base,
                                                  CONTENT_MSG_GETTHREAD,
                                                  &msg_data);
                                NSLOG(netsurf, INFO,
                                      "javascript context: %p (htmlc: %p)",
                                      htmlc->jsthread,
                                      htmlc);
                        }
                        if (htmlc->jsthread != NULL) {
                                js_handle_new_element(htmlc->jsthread,
                                                      (dom_element *) node);
                        }
                }
        }
        dom_node_unref(node);
}
 
 
/**
 * callback for DOMNodeInsertedIntoDocument end type
 */
static void
dom_default_action_DOMNodeInsertedIntoDocument_cb(struct dom_event *evt,
                                                  void *pw)
{
        html_content *htmlc = pw;
        dom_event_target *node;
        dom_node_type type;
        dom_exception exc;
 
        exc = dom_event_get_target(evt, &node);
        if ((exc == DOM_NO_ERR) && (node != NULL)) {
                exc = dom_node_get_node_type(node, &type);
                if ((exc == DOM_NO_ERR) && (type == DOM_ELEMENT_NODE)) {
                        /* an element node has been modified */
                        dom_html_element_type tag_type;
 
                        exc = dom_html_element_get_tag_type(node, &tag_type);
                        if (exc != DOM_NO_ERR) {
                                tag_type = DOM_HTML_ELEMENT_TYPE__UNKNOWN;
                        }
 
                        switch (tag_type) {
                        case DOM_HTML_ELEMENT_TYPE_SCRIPT:
                                dom_SCRIPT_showed_up(htmlc, (dom_html_script_element *) node);
                                fallthrough;
                        default:
                                break;
                        }
                }
                dom_node_unref(node);
        }
}
 
 
/**
 * callback for DOMSubtreeModified end type
 */
static void
dom_default_action_DOMSubtreeModified_cb(struct dom_event *evt, void *pw)
{
        dom_event_target *node;
        dom_node_type type;
        dom_exception exc;
        html_content *htmlc = pw;
 
        exc = dom_event_get_target(evt, &node);
        if ((exc == DOM_NO_ERR) && (node != NULL)) {
                if (htmlc->title == (dom_node *)node) {
                        /* Node is our title node */
                        html_process_title(htmlc, (dom_node *)node);
                        dom_node_unref(node);
                        return;
                }
 
                exc = dom_node_get_node_type(node, &type);
                if ((exc == DOM_NO_ERR) && (type == DOM_ELEMENT_NODE)) {
                        /* an element node has been modified */
                        dom_html_element_type tag_type;
 
                        exc = dom_html_element_get_tag_type(node, &tag_type);
                        if (exc != DOM_NO_ERR) {
                                tag_type = DOM_HTML_ELEMENT_TYPE__UNKNOWN;
                        }
 
                        switch (tag_type) {
                        case DOM_HTML_ELEMENT_TYPE_STYLE:
                                if (nsoption_bool(author_level_css)) {
                                        html_css_update_style(htmlc,
                                                        (dom_node *)node);
                                }
                                break;
                        case DOM_HTML_ELEMENT_TYPE_TEXTAREA:
                        case DOM_HTML_ELEMENT_TYPE_INPUT:
                                html_texty_element_update(htmlc, (dom_node *)node);
                                fallthrough;
                        default:
                                break;
                        }
                }
                dom_node_unref(node);
        }
}
 
 
/**
 * callback for default action finished
 */
static void
dom_default_action_finished_cb(struct dom_event *evt, void *pw)
{
        html_content *htmlc = pw;
 
        if (htmlc->jsthread != NULL)
                js_event_cleanup(htmlc->jsthread, evt);
}
 
 
/* exported interface documented in html/dom_event.c */
dom_default_action_callback
html_dom_event_fetcher(dom_string *type,
                  dom_default_action_phase phase,
                  void **pw)
{
        NSLOG(netsurf, DEEPDEBUG,
              "phase:%d type:%s", phase, dom_string_data(type));
 
        if (phase == DOM_DEFAULT_ACTION_END) {
                if (dom_string_isequal(type, corestring_dom_DOMNodeInserted)) {
                        return dom_default_action_DOMNodeInserted_cb;
                } else if (dom_string_isequal(type, corestring_dom_DOMNodeInsertedIntoDocument)) {
                        return dom_default_action_DOMNodeInsertedIntoDocument_cb;
                } else if (dom_string_isequal(type, corestring_dom_DOMSubtreeModified)) {
                        return dom_default_action_DOMSubtreeModified_cb;
                }
        } else if (phase == DOM_DEFAULT_ACTION_FINISHED) {
                return dom_default_action_finished_cb;
        }
        return NULL;
}