png.c

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/*
 * Copyright 2004 James Bursa <bursa@users.sourceforge.net>
 * Copyright 2004 Richard Wilson <not_ginger_matt@hotmail.com>
 * Copyright 2008 Daniel Silverstone <dsilvers@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/>.
 */
 
#include <stdbool.h>
#include <string.h>
#include <stdlib.h>
#include <png.h>
 
#include "netsurf/inttypes.h"
#include "utils/utils.h"
#include "utils/log.h"
#include "utils/messages.h"
#include "netsurf/bitmap.h"
#include "content/llcache.h"
#include "content/content_protected.h"
#include "content/content_factory.h"
#include "desktop/gui_internal.h"
#include "desktop/bitmap.h"
 
#include "image/image_cache.h"
#include "image/png.h"
 
/* accommodate for old versions of libpng (beware security holes!) */
 
#ifndef png_jmpbuf
#warning you have an antique libpng
#define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf)
#endif
 
#if PNG_LIBPNG_VER < 10209
#define png_set_expand_gray_1_2_4_to_8(png) png_set_gray_1_2_4_to_8(png)
#endif
 
typedef struct nspng_content {
        struct content base; /**< base content type */
 
        bool no_process_data; /**< Do not continue to process data as it arrives */
        png_structp png;
        png_infop info;
        int interlace;
        struct bitmap *bitmap;  /**< Created NetSurf bitmap */
        size_t rowstride, bpp; /**< Bitmap rowstride and bpp */
        size_t rowbytes; /**< Number of bytes per row */
} nspng_content;
 
static unsigned int interlace_start[8] = {0, 16, 0, 8, 0, 4, 0};
static unsigned int interlace_step[8] = {28, 28, 12, 12, 4, 4, 0};
static unsigned int interlace_row_start[8] = {0, 0, 4, 0, 2, 0, 1};
static unsigned int interlace_row_step[8] = {8, 8, 8, 4, 4, 2, 2};
 
/** Callbak error numbers*/
enum nspng_cberr {
        CBERR_NONE = 0, /* no error */
        CBERR_LIBPNG, /* error from png library */
        CBERR_NOPRE, /* no pre-conversion performed */
}; 
 
/**
 * nspng_warning -- callback for libpng warnings
 */
static void nspng_warning(png_structp png_ptr, png_const_charp warning_message)
{
        NSLOG(netsurf, INFO, "%s", warning_message);
}
 
/**
 * nspng_error -- callback for libpng errors
 */
static void nspng_error(png_structp png_ptr, png_const_charp error_message)
{
        NSLOG(netsurf, INFO, "%s", error_message);
        longjmp(png_jmpbuf(png_ptr), CBERR_LIBPNG);
}
 
static void nspng_setup_transforms(png_structp png_ptr, png_infop info_ptr)
{
        int bit_depth, color_type, intent;
        double gamma;
 
        bit_depth = png_get_bit_depth(png_ptr, info_ptr);
        color_type = png_get_color_type(png_ptr, info_ptr);
 
        /* Set up our transformations */
        if (color_type == PNG_COLOR_TYPE_PALETTE) {
                png_set_palette_to_rgb(png_ptr);
        }
 
        if ((color_type == PNG_COLOR_TYPE_GRAY) && (bit_depth < 8)) {
                png_set_expand_gray_1_2_4_to_8(png_ptr);
        }
 
        if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
                png_set_tRNS_to_alpha(png_ptr);
        }
 
        if (bit_depth == 16) {
                png_set_strip_16(png_ptr);
        }
 
        if (color_type == PNG_COLOR_TYPE_GRAY ||
            color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
                png_set_gray_to_rgb(png_ptr);
        }
 
        switch (bitmap_fmt.layout) {
        case BITMAP_LAYOUT_B8G8R8A8: /* Fall through. */
        case BITMAP_LAYOUT_A8B8G8R8:
                png_set_bgr(png_ptr);
                break;
        default:
                /* RGB is the default. */
                break;
        }
 
        if (!(color_type & PNG_COLOR_MASK_ALPHA)) {
                switch (bitmap_fmt.layout) {
                case BITMAP_LAYOUT_A8R8G8B8: /* Fall through. */
                case BITMAP_LAYOUT_A8B8G8R8:
                        png_set_filler(png_ptr, 0xff, PNG_FILLER_BEFORE);
                        break;
 
                default:
                        png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER);
                        break;
                }
        } else {
                switch (bitmap_fmt.layout) {
                case BITMAP_LAYOUT_A8R8G8B8: /* Fall through. */
                case BITMAP_LAYOUT_A8B8G8R8:
                        png_set_swap_alpha(png_ptr);
                        break;
                default:
                        /* Alpha as final component is the default. */
                        break;
                }
        }
 
        /* gamma correction - we use 2.2 as our screen gamma
         * this appears to be correct (at least in respect to !Browse)
         * see http://www.w3.org/Graphics/PNG/all_seven.html for a test case
         */
        if (png_get_sRGB(png_ptr, info_ptr, &intent)) {
                png_set_gamma(png_ptr, 2.2, 0.45455);
        } else {
                if (png_get_gAMA(png_ptr, info_ptr, &gamma)) {
                        png_set_gamma(png_ptr, 2.2, gamma);
                } else {
                        png_set_gamma(png_ptr, 2.2, 0.45455);
                }
        }
 
        png_read_update_info(png_ptr, info_ptr);
}
 
/**
 * info_callback -- PNG header has been completely received, prepare to process
 * image data
 */
static void info_callback(png_structp png_s, png_infop info)
{
        int interlace;
        png_uint_32 width, height;
        nspng_content *png_c = png_get_progressive_ptr(png_s);
 
        width = png_get_image_width(png_s, info);
        height = png_get_image_height(png_s, info);
        interlace = png_get_interlace_type(png_s, info);
 
        png_c->base.width = width;
        png_c->base.height = height;
        png_c->base.size += width * height * 4;
 
        /* see if progressive-conversion should continue */
        if (image_cache_speculate((struct content *)png_c) == false) {
                longjmp(png_jmpbuf(png_s), CBERR_NOPRE);
        }
 
        /* Claim the required memory for the converted PNG */
        png_c->bitmap = guit->bitmap->create(width, height, BITMAP_NONE);
        if (png_c->bitmap == NULL) {
                /* Failed to create bitmap skip pre-conversion */
                longjmp(png_jmpbuf(png_s), CBERR_NOPRE);
        }
 
        png_c->rowstride = guit->bitmap->get_rowstride(png_c->bitmap);
        png_c->bpp = sizeof(uint32_t);
 
        nspng_setup_transforms(png_s, info);
 
        png_c->rowbytes = png_get_rowbytes(png_s, info);
        png_c->interlace = (interlace == PNG_INTERLACE_ADAM7);
 
        NSLOG(netsurf, INFO, "size %li * %li, rowbytes %"PRIsizet,
              (unsigned long)width, (unsigned long)height, png_c->rowbytes);
}
 
static void row_callback(png_structp png_s, png_bytep new_row,
                         png_uint_32 row_num, int pass)
{
        nspng_content *png_c = png_get_progressive_ptr(png_s);
        unsigned long rowbytes = png_c->rowbytes;
        unsigned char *buffer, *row;
 
        /* Give up if there's no bitmap */
        if (png_c->bitmap == NULL)
                return;
 
        /* Abort if we've not got any data */
        if (new_row == NULL)
                return;
 
        /* Get bitmap buffer */
        buffer = guit->bitmap->get_buffer(png_c->bitmap);
        if (buffer == NULL) {
                /* No buffer, bail out */
                longjmp(png_jmpbuf(png_s), 1);
        }
 
        /* Calculate address of row start */
        row = buffer + (png_c->rowstride * row_num);
 
        /* Handle interlaced sprites using the Adam7 algorithm */
        if (png_c->interlace) {
                unsigned long dst_off;
                unsigned long src_off = 0;
                unsigned int start, step;
 
                start = interlace_start[pass];
                step = interlace_step[pass];
                row_num = interlace_row_start[pass] +
                        interlace_row_step[pass] * row_num;
 
                /* Copy the data to our current row taking interlacing
                 * into consideration */
                row = buffer + (png_c->rowstride * row_num);
 
                for (dst_off = start; dst_off < rowbytes; dst_off += step) {
                        row[dst_off++] = new_row[src_off++];
                        row[dst_off++] = new_row[src_off++];
                        row[dst_off++] = new_row[src_off++];
                        row[dst_off++] = new_row[src_off++];
                }
        } else {
                /* Do a fast memcpy of the row data */
                memcpy(row, new_row, rowbytes);
        }
}
 
 
static void end_callback(png_structp png_s, png_infop info)
{
}
 
static nserror nspng_create_png_data(nspng_content *png_c)
{
        png_c->bitmap = NULL;
 
        png_c->png = png_create_read_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0);
        if (png_c->png == NULL) {
                content_broadcast_error(&png_c->base, NSERROR_NOMEM, NULL);
                return NSERROR_NOMEM;
        }
 
        png_set_error_fn(png_c->png, NULL, nspng_error, nspng_warning);
 
        png_c->info = png_create_info_struct(png_c->png);
        if (png_c->info == NULL) {
                png_destroy_read_struct(&png_c->png, &png_c->info, 0);
 
                content_broadcast_error(&png_c->base, NSERROR_NOMEM, NULL);
                return NSERROR_NOMEM;
        }
 
        if (setjmp(png_jmpbuf(png_c->png))) {
                png_destroy_read_struct(&png_c->png, &png_c->info, 0);
                NSLOG(netsurf, INFO, "Failed to set callbacks");
                png_c->png = NULL;
                png_c->info = NULL;
 
                content_broadcast_error(&png_c->base, NSERROR_PNG_ERROR, NULL);
                return NSERROR_NOMEM;
        }
 
        png_set_progressive_read_fn(png_c->png, png_c,
                        info_callback, row_callback, end_callback);
 
        return NSERROR_OK;
}
 
static nserror
nspng_create(const content_handler *handler,
             lwc_string *imime_type,
             const struct http_parameter *params,
             struct llcache_handle *llcache,
             const char *fallback_charset,
             bool quirks,
             struct content **c)
{
        nspng_content *png_c;
        nserror error;
 
        png_c = calloc(1, sizeof(nspng_content));
        if (png_c == NULL)
                return NSERROR_NOMEM;
 
        error = content__init(&png_c->base, 
                              handler, 
                              imime_type, 
                              params,
                              llcache, 
                              fallback_charset, 
                              quirks);
        if (error != NSERROR_OK) {
                free(png_c);
                return error;
        }
 
        error = nspng_create_png_data(png_c);
        if (error != NSERROR_OK) {
                free(png_c);
                return error;
        }
 
        *c = (struct content *)png_c;
 
        return NSERROR_OK;
}
 
 
static bool nspng_process_data(struct content *c, const char *data,
                               unsigned int size)
{
        nspng_content *png_c = (nspng_content *)c;
        volatile bool ret = true;
 
        if (png_c->no_process_data) {
                return ret;
        }
 
        switch (setjmp(png_jmpbuf(png_c->png))) {
        case CBERR_NONE: /* direct return */    
                png_process_data(png_c->png, png_c->info, (uint8_t *)data, size);
                break;
 
        case CBERR_NOPRE: /* not going to progressive convert */
                png_c->no_process_data = true;
                break;
 
        default: /* fatal error from library processing png */
                if (png_c->bitmap != NULL) {
                        /* A bitmap managed to get created so
                         * operation is past header and possibly some
                         * conversion happened before faliure. 
                         *
                         * In this case keep the partial
                         * conversion. This is usually seen if a png
                         * has been truncated (often jsut lost its
                         * last byte and hence end of image marker)
                         */
                        png_c->no_process_data = true;
                } else {
                        /* not managed to progress past header, clean
                         * up png conversion and signal the content
                         * error 
                         */
                        NSLOG(netsurf, INFO,
                              "Fatal PNG error during header, error content");
 
                        png_destroy_read_struct(&png_c->png, &png_c->info, 0);
                        png_c->png = NULL;
                        png_c->info = NULL;
 
                        content_broadcast_error(c, NSERROR_PNG_ERROR, NULL);
 
                        ret = false;
 
                }
                break;
        }
 
        return ret;
}
 
struct png_cache_read_data_s {
        const uint8_t *data;
        size_t size;
};
 
/** PNG library read fucntion to read data from a memory array 
 */
static void 
png_cache_read_fn(png_structp png_ptr, png_bytep data, png_size_t length)
{
        struct png_cache_read_data_s *png_cache_read_data;
        png_cache_read_data = png_get_io_ptr(png_ptr);
 
        if (length > png_cache_read_data->size) {
                length = png_cache_read_data->size;
        }
 
        if (length == 0) {
                png_error(png_ptr, "Read Error");
        }
 
        memcpy(data, png_cache_read_data->data, length);
 
        png_cache_read_data->data += length;
        png_cache_read_data->size -= length;
}
 
/** calculate an array of row pointers into a bitmap data area
 */
static png_bytep *calc_row_pointers(struct bitmap *bitmap)
{
        int height = guit->bitmap->get_height(bitmap);
        unsigned char *buffer= guit->bitmap->get_buffer(bitmap);
        size_t rowstride = guit->bitmap->get_rowstride(bitmap);
        png_bytep *row_ptrs;
        int hloop;
 
        /* The buffer allocation may occour when the buffer is aquired
         * and therefore may fail.
         */
        if (buffer == NULL) {
                return NULL;
        }
 
        row_ptrs = malloc(sizeof(png_bytep) * height);
 
        if (row_ptrs != NULL) {
                for (hloop = 0; hloop < height; hloop++) {
                        row_ptrs[hloop] = buffer + (rowstride * hloop);
                }
        }
 
        return row_ptrs;
}
 
/** PNG content to bitmap conversion.
 *
 * This routine generates a bitmap object from a PNG image content
 */
static struct bitmap *
png_cache_convert(struct content *c)
{
        png_structp png_ptr;
        png_infop info_ptr;
        png_infop end_info_ptr;
        volatile struct bitmap * volatile bitmap = NULL;
        struct png_cache_read_data_s png_cache_read_data;
        png_uint_32 width, height;
        volatile png_bytep * volatile row_pointers = NULL;
 
        png_cache_read_data.data = 
                content__get_source_data(c, &png_cache_read_data.size);
 
        if ((png_cache_read_data.data == NULL) || 
            (png_cache_read_data.size <= 8)) {
                return NULL;
        }
 
        png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL,
                        nspng_error, nspng_warning);
        if (png_ptr == NULL) {
                return NULL;
        }
 
        info_ptr = png_create_info_struct(png_ptr);
        if (info_ptr == NULL) {
                png_destroy_read_struct(&png_ptr, NULL, NULL);
                return NULL;
        }
 
        end_info_ptr = png_create_info_struct(png_ptr);
        if (end_info_ptr == NULL) {
                png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
                return NULL;
        }
 
        /* setup error exit path */
        if (setjmp(png_jmpbuf(png_ptr))) {
                /* cleanup and bail */
                goto png_cache_convert_error;
        }
 
        /* read from a buffer instead of stdio */
        png_set_read_fn(png_ptr, &png_cache_read_data, png_cache_read_fn);
 
        /* ensure the png info structure is populated */
        png_read_info(png_ptr, info_ptr);
 
        /* setup output transforms */
        nspng_setup_transforms(png_ptr, info_ptr);
 
        width = png_get_image_width(png_ptr, info_ptr);
        height = png_get_image_height(png_ptr, info_ptr);
 
        /* Claim the required memory for the converted PNG */
        bitmap = guit->bitmap->create(width, height, BITMAP_NONE);
        if (bitmap == NULL) {
                /* cleanup and bail */
                goto png_cache_convert_error;
        }
 
        row_pointers = calc_row_pointers((struct bitmap *) bitmap);
 
        if (row_pointers != NULL) {
                png_read_image(png_ptr, (png_bytep *) row_pointers);
        } else {
                guit->bitmap->destroy((struct bitmap *)bitmap);
                bitmap = NULL;
        }
 
png_cache_convert_error:
 
        /* cleanup png read */
        png_destroy_read_struct(&png_ptr, &info_ptr, &end_info_ptr);
 
        if (row_pointers != NULL) {
                free((png_bytep *) row_pointers);
        }
 
        if (bitmap != NULL) {
                bool opaque = bitmap_test_opaque((void *)bitmap);
                guit->bitmap->set_opaque((void *)bitmap, opaque);
                bitmap_format_to_client((void *)bitmap, &(bitmap_fmt_t) {
                        .layout = bitmap_fmt.layout,
                        .pma = opaque ? bitmap_fmt.pma : false,
                });
                guit->bitmap->modified((void *)bitmap);
        }
 
        return (struct bitmap *)bitmap;
}
 
static bool nspng_convert(struct content *c)
{
        nspng_content *png_c = (nspng_content *) c;
        char *title;
 
        assert(png_c->png != NULL);
        assert(png_c->info != NULL);
 
        /* clean up png structures */
        png_destroy_read_struct(&png_c->png, &png_c->info, 0);
 
        /* set title text */
        title = messages_get_buff("PNGTitle",
                        nsurl_access_leaf(llcache_handle_get_url(c->llcache)),
                        c->width, c->height);
        if (title != NULL) {
                content__set_title(c, title);
                free(title);
        }
 
        if (png_c->bitmap != NULL) {
                bool opaque = bitmap_test_opaque(png_c->bitmap);
                guit->bitmap->set_opaque(png_c->bitmap, opaque);
                bitmap_format_to_client(png_c->bitmap, &(bitmap_fmt_t) {
                        .layout = bitmap_fmt.layout,
                        .pma = opaque ? bitmap_fmt.pma : false,
                });
                guit->bitmap->modified(png_c->bitmap);
        }
 
        image_cache_add(c, png_c->bitmap, png_cache_convert);
 
        content_set_ready(c);
        content_set_done(c);
        content_set_status(c, "");
 
        return true;
}
 
 
static nserror nspng_clone(const struct content *old_c, struct content **new_c)
{
        nspng_content *clone_png_c;
        nserror error;
        const uint8_t *data;
        size_t size;
 
        clone_png_c = calloc(1, sizeof(nspng_content));
        if (clone_png_c == NULL)
                return NSERROR_NOMEM;
 
        error = content__clone(old_c, &clone_png_c->base);
        if (error != NSERROR_OK) {
                content_destroy(&clone_png_c->base);
                return error;
        }
 
        /* Simply replay create/process/convert */
        error = nspng_create_png_data(clone_png_c);
        if (error != NSERROR_OK) {
                content_destroy(&clone_png_c->base);
                return error;
        }
 
        data = content__get_source_data(&clone_png_c->base, &size);
        if (size > 0) {
                if (nspng_process_data(&clone_png_c->base, (const char *)data, size) == false) {
                        content_destroy(&clone_png_c->base);
                        return NSERROR_NOMEM;
                }
        }
 
        if ((old_c->status == CONTENT_STATUS_READY) ||
            (old_c->status == CONTENT_STATUS_DONE)) {
                if (nspng_convert(&clone_png_c->base) == false) {
                        content_destroy(&clone_png_c->base);
                        return NSERROR_CLONE_FAILED;
                }
        }
 
        *new_c = (struct content *)clone_png_c;
 
        return NSERROR_OK;
}
 
static const content_handler nspng_content_handler = {
        .create = nspng_create,
        .process_data = nspng_process_data,
        .data_complete = nspng_convert,
        .clone = nspng_clone,
        .destroy = image_cache_destroy,
        .redraw = image_cache_redraw,
        .get_internal = image_cache_get_internal,
        .type = image_cache_content_type,
        .is_opaque = image_cache_is_opaque,
        .no_share = false,
};
 
static const char *nspng_types[] = {
        "image/png",
        "image/x-png"
};
 
CONTENT_FACTORY_REGISTER_TYPES(nspng, nspng_types, nspng_content_handler);