path: root/gdk-pixbuf/gdk-pixbuf-io.c

/* GdkPixbuf library - Main loading interface.
 *
 * Copyright (C) 1999 The Free Software Foundation
 *
 * Authors: Miguel de Icaza <miguel@gnu.org>
 *          Federico Mena-Quintero <federico@gimp.org>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
 */

#include "config.h"

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#include <glib.h>
#include <gio/gio.h>

#include "gdk-pixbuf-private.h"
#include "gdk-pixbuf-loader.h"
#include "gdk-pixdata.h"

#include <glib/gstdio.h>

#ifdef G_OS_WIN32
#define STRICT
#include <windows.h>
#undef STRICT
#endif
#ifdef OS_DARWIN
#include <mach-o/dyld.h>
#endif

/**
 * SECTION:file-loading
 * @Short_description: Loading a pixbuf from a file.
 * @Title: File Loading
 * @See_also: #GdkPixbufLoader.
 * 
 * The GdkPixBuf library provides a simple mechanism for loading
 * an image from a file in synchronous fashion.  This means that the
 * library takes control of the application while the file is being
 * loaded; from the user's point of view, the application will block
 * until the image is done loading.
 * 
 * 
 * This interface can be used by applications in which blocking is
 * acceptable while an image is being loaded.  It can also be used to
 * load small images in general.  Applications that need progressive
 * loading can use the #GdkPixbufLoader functionality instead.
 */

/**
 * SECTION:file-saving
 * @Short_description: Saving a pixbuf to a file.
 * @Title: File saving
 * 
 * These functions allow to save a #GdkPixbuf in a number of 
 * file formats. The formatted data can be written to a file
 * or to a memory buffer. GdkPixBuf can also call a user-defined
 * callback on the data, which allows to e.g. write the image 
 * to a socket or store it in a database.
 */

/**
 * SECTION:module_interface
 * @Short_description: Extending GdkPixBuf
 * @Title: Module Interface
 * 
 * If GdkPixBuf has been compiled with GModule support, it can be extended by
 * modules which can load (and perhaps also save) new image and animation
 * formats. Each loadable module must export a
 * #GdkPixbufModuleFillInfoFunc function named `fill_info` and
 * a #GdkPixbufModuleFillVtableFunc function named
 * `fill_vtable`.
 * 
 * In order to make format-checking work before actually loading the modules
 * (which may require dlopening image libraries), modules export their 
 * signatures (and other information) via the `fill_info` function. An
 * external utility, gdk-pixbuf-query-loaders, uses this to create a text
 * file containing a list of all available loaders and  their signatures.
 * This file is then read at runtime by GdkPixBuf to obtain the list of
 * available loaders and their signatures. 
 * 
 * Modules may only implement a subset of the functionality available via
 * #GdkPixbufModule. If a particular functionality is not implemented, the
 * `fill_vtable` function will simply not set the corresponding
 * function pointers of the #GdkPixbufModule structure. If a module supports
 * incremental loading (i.e. provides #begin_load, #stop_load and
 * #load_increment), it doesn't have to implement #load, since GdkPixBuf can
 * supply a generic #load implementation wrapping the incremental loading. 
 * 
 * Installing a module is a two-step process:
 * - copy the module file(s) to the loader directory (normally
 *   `$libdir/gdk-pixbuf-2.0/$version/loaders`, unless overridden by the
 *   environment variable `GDK_PIXBUF_MODULEDIR`) 
 * - call gdk-pixbuf-query-loaders to update the module file (normally
 *   `$libdir/gdk-pixbuf-2.0/$version/loaders.cache`, unless overridden by the
 *   environment variable `GDK_PIXBUF_MODULE_FILE`)
 * 
 * The GdkPixBuf interfaces needed for implementing modules are contained in
 * `gdk-pixbuf-io.h` (and `gdk-pixbuf-animation.h` if the module supports
 * animations). They are not covered by the same stability guarantees as the
 * regular  GdkPixBuf API. To underline this fact, they are protected by
 * `#ifdef GDK_PIXBUF_ENABLE_BACKEND`.
 */


static gint 
format_check (GdkPixbufModule *module, guchar *buffer, int size)
{
        int i, j;
        gchar m;
        GdkPixbufModulePattern *pattern;
        gboolean anchored;
        guchar *prefix;
        gchar *mask;

        for (pattern = module->info->signature; pattern->prefix; pattern++) {
                if (pattern->mask && pattern->mask[0] == '*') {
                        prefix = (guchar *)pattern->prefix + 1;
                        mask = pattern->mask + 1;
                        anchored = FALSE;
                }
                else {
                        prefix = (guchar *)pattern->prefix;
                        mask = pattern->mask;
                        anchored = TRUE;
                }
                for (i = 0; i < size; i++) {
                        for (j = 0; i + j < size && prefix[j] != 0; j++) {
                                m = mask ? mask[j] : ' ';
                                if (m == ' ') {
                                        if (buffer[i + j] != prefix[j])
                                                break;
                                }
                                else if (m == '!') {
                                        if (buffer[i + j] == prefix[j])
                                                break;
                                }
                                else if (m == 'z') {
                                        if (buffer[i + j] != 0)
                                                break;
                                }
                                else if (m == 'n') {
                                        if (buffer[i + j] == 0)
                                                break;
                                }
                        } 

                        if (prefix[j] == 0) 
                                return pattern->relevance;

                        if (anchored)
                                break;
                }
        }
        return 0;
}

G_LOCK_DEFINE_STATIC (init_lock);

static gboolean file_formats_inited;
static GSList *file_formats = NULL;

static gboolean gdk_pixbuf_io_init (void);

static GSList *
get_file_formats (void)
{
        G_LOCK (init_lock);
        if (file_formats == NULL ||
            !file_formats_inited)
                file_formats_inited = gdk_pixbuf_io_init ();
        G_UNLOCK (init_lock);
        
        return file_formats;
}

#ifdef G_OS_WIN32

/* DllMain function needed to tuck away the gdk-pixbuf DLL handle */

static HMODULE gdk_pixbuf_dll;

BOOL WINAPI
DllMain (HINSTANCE hinstDLL,
         DWORD     fdwReason,
         LPVOID    lpvReserved)
{
        switch (fdwReason) {
        case DLL_PROCESS_ATTACH:
                gdk_pixbuf_dll = (HMODULE) hinstDLL;
                break;
        }

  return TRUE;
}
#endif


#ifdef GDK_PIXBUF_RELOCATABLE

gchar *
gdk_pixbuf_get_toplevel (void)
{
  static gchar *toplevel = NULL;

  if (toplevel == NULL) {
#if defined(G_OS_WIN32)
    toplevel = g_win32_get_package_installation_directory_of_module (gdk_pixbuf_dll);
#elif defined(OS_DARWIN)
    char pathbuf[PATH_MAX + 1];
    uint32_t  bufsize = sizeof(pathbuf);
    gchar *bin_dir;

    _NSGetExecutablePath(pathbuf, &bufsize);
    bin_dir = g_dirname(pathbuf);
    toplevel = g_build_path (G_DIR_SEPARATOR_S, bin_dir, "..", NULL);
    g_free (bin_dir);
#elif defined (OS_LINUX)
    gchar *exe_path, *bin_dir;

    exe_path = g_file_read_link ("/proc/self/exe", NULL);
    bin_dir = g_dirname(exe_path);
    toplevel = g_build_path (G_DIR_SEPARATOR_S, bin_dir, "..", NULL);
    g_free (exe_path);
    g_free (bin_dir);
#else
#error "Relocations not supported for this platform"
#endif
  }
  return toplevel;
}

#endif  /* GDK_PIXBUF_RELOCATABLE */


#ifdef USE_GMODULE 

static gboolean
scan_string (const char **pos, GString *out)
{
        const char *p = *pos, *q = *pos;
        char *tmp, *tmp2;
        gboolean quoted;
        
        while (g_ascii_isspace (*p))
                p++;
        
        if (!*p)
                return FALSE;
        else if (*p == '"') {
                p++;
                quoted = FALSE;
                for (q = p; (*q != '"') || quoted; q++) {
                        if (!*q)
                                return FALSE;
                        quoted = (*q == '\\') && !quoted;
                }
                
                tmp = g_strndup (p, q - p);
                tmp2 = g_strcompress (tmp);
                g_string_truncate (out, 0);
                g_string_append (out, tmp2);
                g_free (tmp);
                g_free (tmp2);
        }
        
        q++;
        *pos = q;
        
        return TRUE;
}

static gboolean
scan_int (const char **pos, int *out)
{
        int i = 0;
        char buf[32];
        const char *p = *pos;
        
        while (g_ascii_isspace (*p))
                p++;
        
        if (*p < '0' || *p > '9')
                return FALSE;
        
        while ((*p >= '0') && (*p <= '9') && i < sizeof (buf)) {
                buf[i] = *p;
                i++;
                p++;
        }
        
        if (i == sizeof (buf))
                return FALSE;
        else
                buf[i] = '\0';
        
        *out = atoi (buf);
        
        *pos = p;

        return TRUE;
}

static gboolean
skip_space (const char **pos)
{
        const char *p = *pos;
        
        while (g_ascii_isspace (*p))
                p++;
  
        *pos = p;
        
        return !(*p == '\0');
}

#ifdef GDK_PIXBUF_RELOCATABLE

static char *
get_libdir (void)
{
  static char *libdir = NULL;

  if (libdir == NULL)
          libdir = g_build_filename (gdk_pixbuf_get_toplevel (), "lib", NULL);

  return libdir;
}

#undef GDK_PIXBUF_LIBDIR
#define GDK_PIXBUF_LIBDIR get_libdir()

#endif  /* GDK_PIXBUF_RELOCATABLE */

/* In case we have a relative module path in the loaders cache
 * prepend the toplevel dir */
static gchar *
build_module_path (const gchar *path)
{
#ifdef GDK_PIXBUF_RELOCATABLE
        if (g_path_is_absolute (path)) {
                return g_strdup (path);
        } else {
                return g_build_filename (gdk_pixbuf_get_toplevel (), path, NULL);
        }
#else
        return g_strdup (path);
#endif
}

static gchar *
gdk_pixbuf_get_module_file (void)
{
  gchar *result = g_strdup (g_getenv ("GDK_PIXBUF_MODULE_FILE"));

  if (!result)
          result = g_build_filename (GDK_PIXBUF_LIBDIR, "gdk-pixbuf-2.0", GDK_PIXBUF_BINARY_VERSION, "loaders.cache", NULL);

  return result;
}

#endif  /* USE_GMODULE */


static gboolean
gdk_pixbuf_load_module_unlocked (GdkPixbufModule *image_module,
                                 GError         **error);

static gboolean
gdk_pixbuf_io_init_modules (const char  *filename,
                            GError     **error)
{
#ifdef USE_GMODULE
        GIOChannel *channel;
        gchar *line_buf;
        gsize term;
        GString *tmp_buf = g_string_new (NULL);
        gboolean have_error = FALSE;
        GdkPixbufModule *module = NULL;
        int flags;
        int n_patterns = 0;
        GdkPixbufModulePattern *pattern;
        GError *local_error = NULL;
        guint num_formats;

        channel = g_io_channel_new_file (filename, "r",  &local_error);
        if (!channel) {
                g_set_error (error,
                             G_IO_ERROR,
                             G_IO_ERROR_INVALID_ARGUMENT,
                             "Cannot open pixbuf loader module file '%s': %s\n\n"
                             "This likely means that your installation is broken.\n"
                             "Try running the command\n"
                             "  gdk-pixbuf-query-loaders > %s\n"
                             "to make things work again for the time being.",
                             filename, local_error->message, filename);
                g_clear_error (&local_error);
                g_string_free (tmp_buf, TRUE);
                return FALSE;
        }

        num_formats = g_slist_length (file_formats);
        
        while (!have_error && g_io_channel_read_line (channel, &line_buf, NULL, &term, NULL) == G_IO_STATUS_NORMAL) {
                const char *p;
                
                p = line_buf;

                line_buf[term] = 0;

                if (!skip_space (&p)) {
                                /* Blank line marking the end of a module
                                 */
                        if (module && *p != '#') {
                                file_formats = g_slist_prepend (file_formats, module);
                                module = NULL;
                        }
                        
                        goto next_line;
                }

                if (*p == '#') 
                        goto next_line;
                
                if (!module) {
                                /* Read a module location
                                 */
                        module = g_new0 (GdkPixbufModule, 1);
                        n_patterns = 0;
                        
                        if (!scan_string (&p, tmp_buf)) {
                                g_warning ("Error parsing loader info in '%s'\n  %s", 
                                           filename, line_buf);
                                have_error = TRUE;
                        }
                        module->module_path = build_module_path (tmp_buf->str);
                }
                else if (!module->module_name) {
                        module->info = g_new0 (GdkPixbufFormat, 1);
                        if (!scan_string (&p, tmp_buf)) {
                                g_warning ("Error parsing loader info in '%s'\n  %s", 
                                           filename, line_buf);
                                have_error = TRUE;
                        }
                        module->info->name =  g_strdup (tmp_buf->str);
                        module->module_name = module->info->name;

                        if (!scan_int (&p, &flags)) {
                                g_warning ("Error parsing loader info in '%s'\n  %s", 
                                           filename, line_buf);
                                have_error = TRUE;
                        }
                        module->info->flags = flags;
                        
                        if (!scan_string (&p, tmp_buf)) {
                                g_warning ("Error parsing loader info in '%s'\n  %s", 
                                           filename, line_buf);
                                have_error = TRUE;
                        }                       
                        if (tmp_buf->str[0] != 0)
                                module->info->domain = g_strdup (tmp_buf->str);

                        if (!scan_string (&p, tmp_buf)) {
                                g_warning ("Error parsing loader info in '%s'\n  %s", 
                                           filename, line_buf);
                                have_error = TRUE;
                        }                       
                        module->info->description = g_strdup (tmp_buf->str);

                        if (scan_string (&p, tmp_buf)) {
                                module->info->license = g_strdup (tmp_buf->str);
                        }
                }
                else if (!module->info->mime_types) {
                        int n = 1;
                        module->info->mime_types = g_new0 (gchar*, 1);
                        while (scan_string (&p, tmp_buf)) {
                                if (tmp_buf->str[0] != 0) {
                                        module->info->mime_types =
                                                g_realloc (module->info->mime_types, (n + 1) * sizeof (gchar*));
                                        module->info->mime_types[n - 1] = g_strdup (tmp_buf->str);
                                        module->info->mime_types[n] = NULL;
                                        n++;
                                }
                        }
                }
                else if (!module->info->extensions) {
                        int n = 1;
                        module->info->extensions = g_new0 (gchar*, 1);
                        while (scan_string (&p, tmp_buf)) {
                                if (tmp_buf->str[0] != 0) {
                                        module->info->extensions =
                                                g_realloc (module->info->extensions, (n + 1) * sizeof (gchar*));
                                        module->info->extensions[n - 1] = g_strdup (tmp_buf->str);
                                        module->info->extensions[n] = NULL;
                                        n++;
                                }
                        }
                }
                else {
                        n_patterns++;
                        module->info->signature = (GdkPixbufModulePattern *)
                                g_realloc (module->info->signature, (n_patterns + 1) * sizeof (GdkPixbufModulePattern));
                        pattern = module->info->signature + n_patterns;
                        pattern->prefix = NULL;
                        pattern->mask = NULL;
                        pattern->relevance = 0;
                        pattern--;
                        if (!scan_string (&p, tmp_buf))
                                goto context_error;
                        pattern->prefix = g_strdup (tmp_buf->str);
                        
                        if (!scan_string (&p, tmp_buf))
                                goto context_error;
                        if (*tmp_buf->str)
                                pattern->mask = g_strdup (tmp_buf->str);
                        else
                                pattern->mask = NULL;
                        
                        if (!scan_int (&p, &pattern->relevance))
                                goto context_error;
                        
                        goto next_line;

                context_error:
                        g_free (pattern->prefix);
                        g_free (pattern->mask);
                        g_free (pattern);
                        g_warning ("Error parsing loader info in '%s'\n  %s", 
                                   filename, line_buf);
                        have_error = TRUE;
                }
        next_line:
                g_free (line_buf);
        }
        g_string_free (tmp_buf, TRUE);
        g_io_channel_unref (channel);

        if (g_slist_length (file_formats) <= num_formats) {
                g_set_error (error,
                             G_IO_ERROR,
                             G_IO_ERROR_NOT_INITIALIZED,
                             "No new GdkPixbufModule loaded from '%s'",
                             filename);
                return FALSE;
        }
#endif
        return TRUE;
}

/**
 * gdk_pixbuf_init_modules:
 * @path: Path to directory where the loaders.cache is installed
 *
 * Initalizes the gdk-pixbuf loader modules referenced by the loaders.cache
 * file present inside that directory.
 *
 * This is to be used by applications that want to ship certain loaders
 * in a different location from the system ones.
 *
 * This is needed when the OS or runtime ships a minimal number of loaders
 * so as to reduce the potential attack surface of carefully crafted image
 * files, especially for uncommon file types. Applications that require
 * broader image file types coverage, such as image viewers, would be
 * expected to ship the gdk-pixbuf modules in a separate location, bundled
 * with the application in a separate directory from the OS or runtime-
 * provided modules.
 *
 * Since: 2.40
 */
gboolean
gdk_pixbuf_init_modules (const char  *path,
			 GError     **error)
{
	char *filename;
	gboolean ret;

	g_return_val_if_fail (path != NULL, FALSE);
	filename = g_build_filename (path, "loaders.cache", NULL);
	ret = gdk_pixbuf_io_init_modules (filename, error);
	g_free (filename);
	return ret;
}

static void
gdk_pixbuf_io_init_builtin (void)
{
#define load_one_builtin_module(format)                                 G_STMT_START { \
        GdkPixbufModule *__builtin_module = g_new0 (GdkPixbufModule, 1);               \
        __builtin_module->module_name = #format;                                       \
        if (gdk_pixbuf_load_module_unlocked (__builtin_module, NULL))                  \
                file_formats = g_slist_prepend (file_formats, __builtin_module);       \
        else                                                                           \
                g_free (__builtin_module);                              } G_STMT_END

#ifdef INCLUDE_ani
        load_one_builtin_module (ani);
#endif
#ifdef INCLUDE_png
        load_one_builtin_module (png);
#endif
#ifdef INCLUDE_bmp
        load_one_builtin_module (bmp);
#endif
#ifdef INCLUDE_gif
        load_one_builtin_module (gif);
#endif
#ifdef INCLUDE_ico
        load_one_builtin_module (ico);
#endif
#ifdef INCLUDE_jpeg
        load_one_builtin_module (jpeg);
#endif
#ifdef INCLUDE_pnm
        load_one_builtin_module (pnm);
#endif
#ifdef INCLUDE_tiff
        load_one_builtin_module (tiff);
#endif
#ifdef INCLUDE_xpm
        load_one_builtin_module (xpm);
#endif
#ifdef INCLUDE_xbm
        load_one_builtin_module (xbm);
#endif
#ifdef INCLUDE_tga
        load_one_builtin_module (tga);
#endif
#ifdef INCLUDE_icns
        load_one_builtin_module (icns);
#endif
#ifdef INCLUDE_jasper
        load_one_builtin_module (jasper);
#endif
#ifdef INCLUDE_qtif
        load_one_builtin_module (qtif);
#endif
#ifdef INCLUDE_gdiplus
        /* We don't bother having the GDI+ loaders individually selectable
         * for building in or not.
         */
        load_one_builtin_module (ico);
        load_one_builtin_module (wmf);
        load_one_builtin_module (emf);
        load_one_builtin_module (bmp);
        load_one_builtin_module (gif);
        load_one_builtin_module (jpeg);
        load_one_builtin_module (tiff);
#endif
#ifdef INCLUDE_gdip_png
        /* Except the gdip-png loader which normally isn't built at all even */
        load_one_builtin_module (png);
#endif

#undef load_one_builtin_module
}

static gboolean
gdk_pixbuf_io_init (void)
{
	char *module_file;
	gboolean ret;

	gdk_pixbuf_io_init_builtin ();
	module_file = gdk_pixbuf_get_module_file ();
	ret = gdk_pixbuf_io_init_modules (module_file, NULL);
	g_free (module_file);
	return ret;
}

#define module(type) \
  extern void _gdk_pixbuf__##type##_fill_info   (GdkPixbufFormat *info);   \
  extern void _gdk_pixbuf__##type##_fill_vtable (GdkPixbufModule *module)

module (png);
module (jpeg);
module (gif);
module (ico);
module (ani);
module (xpm);
module (tiff);
module (pnm);
module (bmp);
module (xbm);
module (tga);
module (icns);
module (jasper);
module (qtif);
module (gdip_ico);
module (gdip_wmf);
module (gdip_emf);
module (gdip_bmp);
module (gdip_gif);
module (gdip_jpeg);
module (gdip_png);
module (gdip_tiff);

#undef module

/* actually load the image handler - gdk_pixbuf_get_module only get a */
/* reference to the module to load, it doesn't actually load it       */
/* perhaps these actions should be combined in one function           */
static gboolean
gdk_pixbuf_load_module_unlocked (GdkPixbufModule *image_module,
                                 GError         **error)
{
        GdkPixbufModuleFillInfoFunc fill_info = NULL;
        GdkPixbufModuleFillVtableFunc fill_vtable = NULL;
                
        if (image_module->module != NULL)
               return TRUE;

#define try_module(format,id)                                           \
        if (fill_info == NULL &&                                        \
            strcmp (image_module->module_name, #format) == 0) {         \
                fill_info = _gdk_pixbuf__##id##_fill_info;              \
                fill_vtable = _gdk_pixbuf__##id##_fill_vtable;  \
        }

#ifdef INCLUDE_gdiplus
        try_module (ico,gdip_ico);
        try_module (wmf,gdip_wmf);
        try_module (emf,gdip_emf);
        try_module (bmp,gdip_bmp);
        try_module (gif,gdip_gif);
        try_module (jpeg,gdip_jpeg);
        try_module (tiff,gdip_tiff);
#endif
#ifdef INCLUDE_gdip_png
        try_module (png,gdip_png);
#endif
#ifdef INCLUDE_png
        try_module (png,png);
#endif
#ifdef INCLUDE_bmp
        try_module (bmp,bmp);
#endif
#ifdef INCLUDE_gif
        try_module (gif,gif);
#endif
#ifdef INCLUDE_ico
        try_module (ico,ico);
#endif
#ifdef INCLUDE_ani
        try_module (ani,ani);
#endif
#ifdef INCLUDE_jpeg
        try_module (jpeg,jpeg);
#endif
#ifdef INCLUDE_pnm
        try_module (pnm,pnm);
#endif
#ifdef INCLUDE_tiff
        try_module (tiff,tiff);
#endif
#ifdef INCLUDE_xpm
        try_module (xpm,xpm);
#endif
#ifdef INCLUDE_xbm
        try_module (xbm,xbm);
#endif
#ifdef INCLUDE_tga
        try_module (tga,tga);
#endif
#ifdef INCLUDE_icns
        try_module (icns,icns);
#endif
#ifdef INCLUDE_jasper
        try_module (jasper,jasper);
#endif
#ifdef INCLUDE_qtif
        try_module (qtif,qtif);
#endif

#undef try_module
        
        if (fill_vtable) {
                image_module->module = (void *) 1;
                (* fill_vtable) (image_module);
                if (image_module->info == NULL) {
                        image_module->info = g_new0 (GdkPixbufFormat, 1);
                        (* fill_info) (image_module->info);
                }
                return TRUE;
        }
        else 
#ifdef USE_GMODULE
        {
                char *path;
                GModule *module;
                gpointer sym;

                path = image_module->module_path;
                module = g_module_open (path, G_MODULE_BIND_LAZY | G_MODULE_BIND_LOCAL);

                if (!module) {
                        g_set_error (error,
                                     GDK_PIXBUF_ERROR,
                                     GDK_PIXBUF_ERROR_FAILED,
                                     _("Unable to load image-loading module: %s: %s"),
                                     path, g_module_error ());
                        return FALSE;
                }

                image_module->module = module;        
        
                if (g_module_symbol (module, "fill_vtable", &sym)) {
                        fill_vtable = (GdkPixbufModuleFillVtableFunc) sym;
                        (* fill_vtable) (image_module);
                        return TRUE;
                } else {
                        g_set_error (error,
                                     GDK_PIXBUF_ERROR,
                                     GDK_PIXBUF_ERROR_FAILED,
                                     _("Image-loading module %s does not export the proper interface; perhaps it’s from a different gdk-pixbuf version?"),
                                     path);
                        return FALSE;
                }
        }
#else
        g_set_error (error,
                     GDK_PIXBUF_ERROR,
                     GDK_PIXBUF_ERROR_UNKNOWN_TYPE,
                     _("Image type “%s” is not supported"),
                     image_module->module_name);
        return FALSE;
#endif  /* !USE_GMODULE */
}


gboolean
_gdk_pixbuf_load_module (GdkPixbufModule *image_module,
                         GError         **error)
{
        gboolean ret;

        G_LOCK (init_lock);

        ret = gdk_pixbuf_load_module_unlocked (image_module, error);

        G_UNLOCK (init_lock);

        return ret;
}



GdkPixbufModule *
_gdk_pixbuf_get_named_module (const char *name,
                              GError **error)
{
        GSList *modules;

        for (modules = get_file_formats (); modules; modules = g_slist_next (modules)) {
                GdkPixbufModule *module = (GdkPixbufModule *)modules->data;

                if (module->info->disabled)
                        continue;

                if (!strcmp (name, module->module_name))
                        return module;
        }

        g_set_error (error,
                     GDK_PIXBUF_ERROR,
                     GDK_PIXBUF_ERROR_UNKNOWN_TYPE,
                     _("Image type “%s” is not supported"),
                     name);
        
        return NULL;
}

GdkPixbufModule *
_gdk_pixbuf_get_module (guchar *buffer, guint size,
                        const gchar *filename,
                        GError **error)
{
        GSList *modules;

        GdkPixbufModule *selected = NULL;
        gchar *display_name = NULL;
#ifdef GDK_PIXBUF_USE_GIO_MIME
        gchar *mime_type;
        gchar **mimes;
        gchar *type;
        gint j;
        gboolean uncertain;

        mime_type = g_content_type_guess (NULL, buffer, size, &uncertain);
        if ((uncertain || g_str_equal (mime_type, "text/plain") || g_str_equal (mime_type, "application/gzip")) && filename != NULL) {
                g_free (mime_type);
                mime_type = g_content_type_guess (filename, buffer, size, NULL);
        }

        for (modules = get_file_formats (); modules; modules = g_slist_next (modules)) {
                GdkPixbufModule *module = (GdkPixbufModule *)modules->data;
                GdkPixbufFormat *info = module->info;

                if (info->disabled)
                        continue;

                mimes = info->mime_types;
                for (j = 0; mimes[j] != NULL; j++) {
                        type = g_content_type_from_mime_type (mimes[j]);
                        if (g_content_type_equals (type, mime_type)) {
                                g_free (type);
                                selected = module;
                                break;
                        }
                        g_free (type);
                }

                if (selected != NULL)
                        break;

		/* Make sure the builtin GdkPixdata support works even without mime sniffing */
		if (strcmp (info->name, "GdkPixdata") == 0 &&
		    format_check (module, buffer, size) == 100) {
			selected = module;
			break;
		}
        }
        g_free (mime_type);
#else
        gint score, best = 0;

        for (modules = get_file_formats (); modules; modules = g_slist_next (modules)) {
                GdkPixbufModule *module = (GdkPixbufModule *)modules->data;

                if (module->info->disabled)
                        continue;

                score = format_check (module, buffer, size);
                if (score > best) {
                        best = score; 
                        selected = module;
                }
                if (score >= 100) 
                        break;
        }
#endif

        if (selected != NULL)
                return selected;

        if (filename)
        {
                display_name = g_filename_display_name (filename);
                g_set_error (error,
                             GDK_PIXBUF_ERROR,
                             GDK_PIXBUF_ERROR_UNKNOWN_TYPE,
                             _("Couldn’t recognize the image file format for file “%s”"),
                             display_name);
                g_free (display_name);
        }
        else
                g_set_error_literal (error,
                                     GDK_PIXBUF_ERROR,
                                     GDK_PIXBUF_ERROR_UNKNOWN_TYPE,
                                     _("Unrecognized image file format"));


        return NULL;
}

static
GdkPixbufModule *
_gdk_pixbuf_get_module_for_file (FILE *f, const gchar *filename, GError **error)
{
        guchar buffer[SNIFF_BUFFER_SIZE];
        int size;

        size = fread (&buffer, 1, sizeof (buffer), f);
        if (size == 0) {
		gchar *display_name;
        	display_name = g_filename_display_name (filename);      
                g_set_error (error,
                             GDK_PIXBUF_ERROR,
                             GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
                             _("Image file “%s” contains no data"),
                             display_name);
                g_free (display_name);
                return NULL;
        }

	return _gdk_pixbuf_get_module (buffer, size, filename, error);
}

static void
prepared_notify (GdkPixbuf *pixbuf, 
                 GdkPixbufAnimation *anim, 
                 gpointer user_data)
{
        if (pixbuf != NULL)
                g_object_ref (pixbuf);
        *((GdkPixbuf **)user_data) = pixbuf;
}

static GdkPixbuf *
generic_load_incrementally (GdkPixbufModule *module, FILE *f, GError **error)
{
        GdkPixbuf *pixbuf = NULL;
	gpointer context;

	context = module->begin_load (NULL, prepared_notify, NULL, &pixbuf, error);
        
	if (!context)
		goto out;
                
	while (!feof (f) && !ferror (f)) {
		guchar buffer[LOAD_BUFFER_SIZE];
		size_t length;

		length = fread (buffer, 1, sizeof (buffer), f);
		if (length > 0) {
			if (!module->load_increment (context, buffer, length, error)) {
				module->stop_load (context, NULL);
				if (pixbuf != NULL) {
					g_object_unref (pixbuf);
					pixbuf = NULL;
				}
				goto out;
			}
		}
	}

	if (!module->stop_load (context, error)) {
		if (pixbuf != NULL) {
			g_object_unref (pixbuf);
			pixbuf = NULL;
		}
	}

out:
	return pixbuf;
}

GdkPixbuf *
_gdk_pixbuf_generic_image_load (GdkPixbufModule *module, FILE *f, GError **error)
{
        GdkPixbuf *pixbuf = NULL;

        if (module->load != NULL) {
                pixbuf = (* module->load) (f, error);
        } else if (module->begin_load != NULL) {
        	pixbuf = generic_load_incrementally (module, f, error);
        } else if (module->load_animation != NULL) {
		GdkPixbufAnimation *animation;

                animation = (* module->load_animation) (f, error);
                if (animation != NULL) {
                        pixbuf = gdk_pixbuf_animation_get_static_image (animation);

                        g_object_ref (pixbuf);
                        g_object_unref (animation);
                }
        }

        return pixbuf;
}

/**
 * gdk_pixbuf_new_from_file:
 * @filename: (type filename): Name of file to load, in the GLib file
 *     name encoding
 * @error: Return location for an error
 *
 * Creates a new pixbuf by loading an image from a file.  The file format is
 * detected automatically. If %NULL is returned, then @error will be set.
 * Possible errors are in the #GDK_PIXBUF_ERROR and #G_FILE_ERROR domains.
 *
 * Return value: A newly-created pixbuf with a reference count of 1, or %NULL if
 * any of several error conditions occurred:  the file could not be opened,
 * there was no loader for the file's format, there was not enough memory to
 * allocate the image buffer, or the image file contained invalid data.
 **/
GdkPixbuf *
gdk_pixbuf_new_from_file (const char *filename,
                          GError    **error)
{
        GdkPixbuf *pixbuf;
        FILE *f;
        GdkPixbufModule *image_module;

        g_return_val_if_fail (filename != NULL, NULL);
        g_return_val_if_fail (error == NULL || *error == NULL, NULL);
        
        f = g_fopen (filename, "rb");
        if (!f) {
                gint save_errno = errno;
		gchar *display_name;
        	display_name = g_filename_display_name (filename);      
                g_set_error (error,
                             G_FILE_ERROR,
                             g_file_error_from_errno (save_errno),
                             _("Failed to open file “%s”: %s"),
                             display_name,
                             g_strerror (save_errno));
                g_free (display_name);
                return NULL;
        }

        image_module = _gdk_pixbuf_get_module_for_file (f, filename, error);
        if (image_module == NULL) {
                fclose (f);
                return NULL;
        }

        if (!_gdk_pixbuf_load_module (image_module, error)) {
                fclose (f);
                return NULL;
        }

        fseek (f, 0, SEEK_SET);
        pixbuf = _gdk_pixbuf_generic_image_load (image_module, f, error);
        fclose (f);

        if (pixbuf == NULL && error != NULL && *error == NULL) {

                /* I don't trust these crufty longjmp()'ing image libs
                 * to maintain proper error invariants, and I don't
                 * want user code to segfault as a result. We need to maintain
                 * the invariant that error gets set if NULL is returned.
                 */

		gchar *display_name;
        	display_name = g_filename_display_name (filename);      
                g_warning ("Bug! gdk-pixbuf loader '%s' didn't set an error on failure.", image_module->module_name);
                g_set_error (error,
                             GDK_PIXBUF_ERROR,
                             GDK_PIXBUF_ERROR_FAILED,
                             _("Failed to load image “%s”: reason not known, probably a corrupt image file"),
                             display_name);
		g_free (display_name);
        } else if (error != NULL && *error != NULL) {
		/* Add the filename to the error message */
		GError *e = *error;
		gchar  *old;
		gchar *display_name;

        	display_name = g_filename_display_name (filename);      
		old = e->message;
		e->message = g_strdup_printf (_("Failed to load image “%s”: %s"),
					      display_name,
					      old);
		g_free (old);
		g_free (display_name);
        }

        return pixbuf;
}

#ifdef G_OS_WIN32

/**
 * gdk_pixbuf_new_from_file_utf8:
 * @filename: (type filename): Name of file to load, in the GLib file name encoding
 * @error: Return location for an error
 *
 * Same as gdk_pixbuf_new_from_file()
 *
 * Return value: A newly-created pixbuf with a reference count of 1, or %NULL if
 * any of several error conditions occurred:  the file could not be opened,
 * there was no loader for the file's format, there was not enough memory to
 * allocate the image buffer, or the image file contained invalid data.
 **/
GdkPixbuf *
gdk_pixbuf_new_from_file_utf8 (const char *filename,
                                GError    **error)
{
    return gdk_pixbuf_new_from_file (filename, error);
}

#endif


/**
 * gdk_pixbuf_new_from_file_at_size:
 * @filename: (type filename): Name of file to load, in the GLib file
 *     name encoding
 * @width: The width the image should have or -1 to not constrain the width
 * @height: The height the image should have or -1 to not constrain the height
 * @error: Return location for an error
 *
 * Creates a new pixbuf by loading an image from a file.  
 * The file format is detected automatically. If %NULL is returned, then 
 * @error will be set. Possible errors are in the #GDK_PIXBUF_ERROR and 
 * #G_FILE_ERROR domains.
 *
 * The image will be scaled to fit in the requested size, preserving
 * the image's aspect ratio. Note that the returned pixbuf may be smaller
 * than @width x @height, if the aspect ratio requires it. To load
 * and image at the requested size, regardless of aspect ratio, use
 * gdk_pixbuf_new_from_file_at_scale().
 *
 * Return value: A newly-created pixbuf with a reference count of 1, or 
 * %NULL if any of several error conditions occurred:  the file could not 
 * be opened, there was no loader for the file's format, there was not 
 * enough memory to allocate the image buffer, or the image file contained 
 * invalid data.
 *
 * Since: 2.4
 **/
GdkPixbuf *
gdk_pixbuf_new_from_file_at_size (const char *filename,
                                  int         width, 
                                  int         height,
                                  GError    **error)
{
        return gdk_pixbuf_new_from_file_at_scale (filename, 
                                                  width, height, 
                                                  TRUE, error);
}

#ifdef G_OS_WIN32

/**
 * gdk_pixbuf_new_from_file_at_size_utf8:
 * @filename: (type filename): Name of file to load, in the GLib file name encoding
 * @width: The width the image should have or -1 to not constrain the width
 * @height: The height the image should have or -1 to not constrain the height
 * @error: Return location for an error
 *
 * Same as gdk_pixbuf_new_from_file_at_size()
 *
 * Return value: A newly-created pixbuf with a reference count of 1, or
 * %NULL if any of several error conditions occurred:  the file could not
 * be opened, there was no loader for the file's format, there was not
 * enough memory to allocate the image buffer, or the image file contained
 * invalid data.
 *
 * Since: 2.4
 **/
GdkPixbuf *
gdk_pixbuf_new_from_file_at_size_utf8 (const char *filename,
                                       int         width,
                                       int         height,
                                       GError    **error)
{
    return gdk_pixbuf_new_from_file_at_size (filename, width, height, error);
}

#endif

typedef struct {
        gint width;
        gint height;
        gboolean preserve_aspect_ratio;
} AtScaleData; 

static void
at_scale_data_async_data_free (AtScaleData *data)
{
	g_slice_free (AtScaleData, data);
}

static void
at_scale_size_prepared_cb (GdkPixbufLoader *loader, 
                           int              width,
                           int              height,
                           gpointer         data)
{
        AtScaleData *info = data;

        g_return_if_fail (width > 0 && height > 0);

        if (info->preserve_aspect_ratio && 
            (info->width > 0 || info->height > 0)) {
                if (info->width < 0)
                {
                        width = width * (double)info->height/(double)height;
                        height = info->height;
                }
                else if (info->height < 0)
                {
                        height = height * (double)info->width/(double)width;
                        width = info->width;
                }
                else if ((double)height * (double)info->width >
                         (double)width * (double)info->height) {
                        width = 0.5 + (double)width * (double)info->height / (double)height;
                        height = info->height;
                } else {
                        height = 0.5 + (double)height * (double)info->width / (double)width;
                        width = info->width;
                }
        } else {
                if (info->width > 0)
                        width = info->width;
                if (info->height > 0)
                        height = info->height;
        }
        
        width = MAX (width, 1);
        height = MAX (height, 1);

        gdk_pixbuf_loader_set_size (loader, width, height);
}

/**
 * gdk_pixbuf_new_from_file_at_scale:
 * @filename: (type filename): Name of file to load, in the GLib file
 *     name encoding
 * @width: The width the image should have or -1 to not constrain the width
 * @height: The height the image should have or -1 to not constrain the height
 * @preserve_aspect_ratio: %TRUE to preserve the image's aspect ratio
 * @error: Return location for an error
 *
 * Creates a new pixbuf by loading an image from a file.  The file format is
 * detected automatically. If %NULL is returned, then @error will be set.
 * Possible errors are in the #GDK_PIXBUF_ERROR and #G_FILE_ERROR domains.
 * The image will be scaled to fit in the requested size, optionally preserving
 * the image's aspect ratio. 
 *
 * When preserving the aspect ratio, a @width of -1 will cause the image
 * to be scaled to the exact given height, and a @height of -1 will cause
 * the image to be scaled to the exact given width. When not preserving
 * aspect ratio, a @width or @height of -1 means to not scale the image 
 * at all in that dimension. Negative values for @width and @height are 
 * allowed since 2.8.
 *
 * Return value: A newly-created pixbuf with a reference count of 1, or %NULL 
 * if any of several error conditions occurred:  the file could not be opened,
 * there was no loader for the file's format, there was not enough memory to
 * allocate the image buffer, or the image file contained invalid data.
 *
 * Since: 2.6
 **/
GdkPixbuf *
gdk_pixbuf_new_from_file_at_scale (const char *filename,
                                   int         width, 
                                   int         height,
                                   gboolean    preserve_aspect_ratio,
                                   GError    **error)
{

        GdkPixbufLoader *loader;
        GdkPixbuf       *pixbuf;
        guchar buffer[LOAD_BUFFER_SIZE];
        int length;
        FILE *f;
        AtScaleData info;
        GdkPixbufAnimation *animation;
        GdkPixbufAnimationIter *iter;
        gboolean has_frame;

        g_return_val_if_fail (filename != NULL, NULL);
        g_return_val_if_fail (width > 0 || width == -1, NULL);
        g_return_val_if_fail (height > 0 || height == -1, NULL);

        f = g_fopen (filename, "rb");
        if (!f) {
                gint save_errno = errno;
                gchar *display_name = g_filename_display_name (filename);
                g_set_error (error,
                             G_FILE_ERROR,
                             g_file_error_from_errno (save_errno),
                             _("Failed to open file “%s”: %s"),
                             display_name,
                             g_strerror (save_errno));
                g_free (display_name);
                return NULL;
        }

        loader = _gdk_pixbuf_loader_new_with_filename (filename);

        info.width = width;
        info.height = height;
        info.preserve_aspect_ratio = preserve_aspect_ratio;

        g_signal_connect (loader, "size-prepared", 
                          G_CALLBACK (at_scale_size_prepared_cb), &info);

        has_frame = FALSE;
        while (!has_frame && !feof (f) && !ferror (f)) {
                length = fread (buffer, 1, sizeof (buffer), f);
                if (length > 0)
                        if (!gdk_pixbuf_loader_write (loader, buffer, length, error)) {
                                gdk_pixbuf_loader_close (loader, NULL);
                                fclose (f);
                                g_object_unref (loader);
                                return NULL;
                        }
                
                animation = gdk_pixbuf_loader_get_animation (loader);
                if (animation) {
                        iter = gdk_pixbuf_animation_get_iter (animation, NULL);
                        if (!gdk_pixbuf_animation_iter_on_currently_loading_frame (iter)) {
                                has_frame = TRUE;
                        }
                        g_object_unref (iter);
                }
        }

        fclose (f);

        if (!gdk_pixbuf_loader_close (loader, error) && !has_frame) {
                g_object_unref (loader);
                return NULL;
        }

        pixbuf = gdk_pixbuf_loader_get_pixbuf (loader);

        if (!pixbuf) {
                gchar *display_name = g_filename_display_name (filename);
                g_object_unref (loader);
                g_set_error (error,
                             GDK_PIXBUF_ERROR,
                             GDK_PIXBUF_ERROR_FAILED,
                             _("Failed to load image “%s”: reason not known, probably a corrupt image file"),
                             display_name);
                g_free (display_name);
                return NULL;
        }

        g_object_ref (pixbuf);

        g_object_unref (loader);

        return pixbuf;
}

#ifdef G_OS_WIN32

/**
 * gdk_pixbuf_new_from_file_at_scale_utf8:
 * @filename: (type filename): Name of file to load, in the GLib file name encoding
 * @width: The width the image should have or -1 to not constrain the width
 * @height: The height the image should have or -1 to not constrain the height
 * @preserve_aspect_ratio: %TRUE to preserve the image's aspect ratio
 * @error: Return location for an error
 *
 * Same as gdk_pixbuf_new_from_file_at_scale().
 *
 * Return value: A newly-created pixbuf with a reference count of 1, or %NULL
 * if any of several error conditions occurred:  the file could not be opened,
 * there was no loader for the file's format, there was not enough memory to
 * allocate the image buffer, or the image file contained invalid data.
 *
 * Since: 2.6
 **/
GdkPixbuf *
gdk_pixbuf_new_from_file_at_scale_utf8 (const char *filename,
                                        int         width,
                                        int         height,
                                        gboolean    preserve_aspect_ratio,
                                        GError    **error)
{
    return gdk_pixbuf_new_from_file_at_scale (filename, width, height,
                                              preserve_aspect_ratio, error);
}
#endif


static GdkPixbuf *
load_from_stream (GdkPixbufLoader  *loader,
                  GInputStream     *stream,
                  GCancellable     *cancellable,
                  GError          **error)
{
        GdkPixbuf *pixbuf;
        gssize n_read;
        guchar buffer[LOAD_BUFFER_SIZE];

        while (1) { 
                n_read = g_input_stream_read (stream, 
                                              buffer, 
                                              sizeof (buffer), 
                                              cancellable, 
                                              error);
                if (n_read < 0) {
                        gdk_pixbuf_loader_close (loader, NULL);
                        return NULL;
                }

                if (n_read == 0)
                        break;

                if (!gdk_pixbuf_loader_write (loader, 
                                              buffer, 
                                              n_read, 
                                              error)) {
                        gdk_pixbuf_loader_close (loader, NULL);
                        return NULL;
                }
        }

        if (!gdk_pixbuf_loader_close (loader, error))
                return NULL;

        pixbuf = gdk_pixbuf_loader_get_pixbuf (loader);
        if (pixbuf == NULL)
                return NULL;

        return g_object_ref (pixbuf);
}


/**
 * gdk_pixbuf_new_from_stream_at_scale:
 * @stream:  a #GInputStream to load the pixbuf from
 * @width: The width the image should have or -1 to not constrain the width
 * @height: The height the image should have or -1 to not constrain the height
 * @preserve_aspect_ratio: %TRUE to preserve the image's aspect ratio
 * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore
 * @error: Return location for an error
 *
 * Creates a new pixbuf by loading an image from an input stream.  
 *
 * The file format is detected automatically. If %NULL is returned, then 
 * @error will be set. The @cancellable can be used to abort the operation
 * from another thread. If the operation was cancelled, the error 
 * %G_IO_ERROR_CANCELLED will be returned. Other possible errors are in 
 * the #GDK_PIXBUF_ERROR and %G_IO_ERROR domains. 
 *
 * The image will be scaled to fit in the requested size, optionally 
 * preserving the image's aspect ratio.
 *
 * When preserving the aspect ratio, a @width of -1 will cause the image to be
 * scaled to the exact given height, and a @height of -1 will cause the image
 * to be scaled to the exact given width. If both @width and @height are
 * given, this function will behave as if the smaller of the two values
 * is passed as -1.
 *
 * When not preserving aspect ratio, a @width or @height of -1 means to not
 * scale the image at all in that dimension.
 *
 * The stream is not closed.
 *
 * Return value: A newly-created pixbuf, or %NULL if any of several error 
 * conditions occurred: the file could not be opened, the image format is 
 * not supported, there was not enough memory to allocate the image buffer, 
 * the stream contained invalid data, or the operation was cancelled.
 *
 * Since: 2.14
 */
GdkPixbuf *
gdk_pixbuf_new_from_stream_at_scale (GInputStream  *stream,
                                     gint           width,
                                     gint           height,
                                     gboolean       preserve_aspect_ratio,
                                     GCancellable  *cancellable,
                                     GError       **error)
{
        GdkPixbufLoader *loader;
        GdkPixbuf *pixbuf;
        AtScaleData info;

        loader = gdk_pixbuf_loader_new ();
        info.width = width;
        info.height = height;
        info.preserve_aspect_ratio = preserve_aspect_ratio;

        g_signal_connect (loader, "size-prepared", 
                          G_CALLBACK (at_scale_size_prepared_cb), &info);

        pixbuf = load_from_stream (loader, stream, cancellable, error);
        g_object_unref (loader);

        return pixbuf;
}


static void
load_from_stream_async_cb (GObject      *stream,
                           GAsyncResult *res,
                           gpointer      data)
{
        GTask *task = data;
        GdkPixbufLoader *loader;
        GdkPixbuf *pixbuf;
        GError *error = NULL;
        GBytes *bytes = NULL;

        loader = g_task_get_task_data (task);

        bytes = g_input_stream_read_bytes_finish (G_INPUT_STREAM (stream), res, &error);

        if (bytes == NULL) {
                gdk_pixbuf_loader_close (loader, NULL);
                g_task_return_error (task, error);
        } else if (g_bytes_get_size (bytes) > 0) {
                if (!gdk_pixbuf_loader_write (loader, 
                                              g_bytes_get_data (bytes, NULL),
                                              g_bytes_get_size (bytes),
                                              &error)) {
                        gdk_pixbuf_loader_close (loader, NULL);
                        g_task_return_error (task, error);
                        goto out;
                }
                g_input_stream_read_bytes_async (G_INPUT_STREAM (stream),
                                                 LOAD_BUFFER_SIZE, 
                                                 G_PRIORITY_DEFAULT,
                                                 g_task_get_cancellable (task),
                                                 load_from_stream_async_cb,
                                                 g_object_ref (task));

        } else {
                if (!gdk_pixbuf_loader_close (loader, &error)) {
                        g_task_return_error (task, error);
                        goto out;
                }

                pixbuf = gdk_pixbuf_loader_get_pixbuf (loader);
                g_task_return_pointer (task, g_object_ref (pixbuf), g_object_unref);
        }

out:
        g_bytes_unref (bytes);
        g_object_unref (task);
}


/**
 * gdk_pixbuf_new_from_stream_at_scale_async:
 * @stream: a #GInputStream from which to load the pixbuf
 * @width: the width the image should have or -1 to not constrain the width
 * @height: the height the image should have or -1 to not constrain the height
 * @preserve_aspect_ratio: %TRUE to preserve the image's aspect ratio
 * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore
 * @callback: a #GAsyncReadyCallback to call when the pixbuf is loaded
 * @user_data: the data to pass to the callback function
 *
 * Creates a new pixbuf by asynchronously loading an image from an input stream.
 *
 * For more details see gdk_pixbuf_new_from_stream_at_scale(), which is the synchronous
 * version of this function.
 *
 * When the operation is finished, @callback will be called in the main thread.
 * You can then call gdk_pixbuf_new_from_stream_finish() to get the result of the operation.
 *
 * Since: 2.24
 **/
void
gdk_pixbuf_new_from_stream_at_scale_async (GInputStream        *stream,
					   gint                 width,
					   gint                 height,
					   gboolean             preserve_aspect_ratio,
					   GCancellable        *cancellable,
					   GAsyncReadyCallback  callback,
					   gpointer             user_data)
{
	GTask *task;
	AtScaleData *data;
        GdkPixbufLoader *loader;

	g_return_if_fail (G_IS_INPUT_STREAM (stream));
	g_return_if_fail (callback != NULL);
	g_return_if_fail (!cancellable || G_IS_CANCELLABLE (cancellable));

	data = g_slice_new (AtScaleData);
	data->width = width;
	data->height = height;
	data->preserve_aspect_ratio = preserve_aspect_ratio;

        loader = gdk_pixbuf_loader_new ();
        g_signal_connect (loader, "size-prepared", 
                          G_CALLBACK (at_scale_size_prepared_cb), data);
        g_object_set_data_full (G_OBJECT (loader),
                                "gdk-pixbuf-please-kill-me-later", 
                                data,
                                (GDestroyNotify) at_scale_data_async_data_free);

	task = g_task_new (stream, cancellable, callback, user_data);
	g_task_set_source_tag (task, gdk_pixbuf_new_from_stream_at_scale_async);
	g_task_set_task_data (task, loader, g_object_unref);

        g_input_stream_read_bytes_async (stream,
                                         LOAD_BUFFER_SIZE, 
                                         G_PRIORITY_DEFAULT,
                                         cancellable,
                                         load_from_stream_async_cb,
                                         task);
}

/**
 * gdk_pixbuf_new_from_stream:
 * @stream:  a #GInputStream to load the pixbuf from
 * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore
 * @error: Return location for an error
 *
 * Creates a new pixbuf by loading an image from an input stream.  
 *
 * The file format is detected automatically. If %NULL is returned, then 
 * @error will be set. The @cancellable can be used to abort the operation
 * from another thread. If the operation was cancelled, the error 
 * %G_IO_ERROR_CANCELLED will be returned. Other possible errors are in 
 * the #GDK_PIXBUF_ERROR and %G_IO_ERROR domains. 
 *
 * The stream is not closed.
 *
 * Return value: A newly-created pixbuf, or %NULL if any of several error 
 * conditions occurred: the file could not be opened, the image format is 
 * not supported, there was not enough memory to allocate the image buffer, 
 * the stream contained invalid data, or the operation was cancelled.
 *
 * Since: 2.14
 **/
GdkPixbuf *
gdk_pixbuf_new_from_stream (GInputStream  *stream,
                            GCancellable  *cancellable,
                            GError       **error)
{
        GdkPixbuf *pixbuf;
        GdkPixbufLoader *loader;

        loader = gdk_pixbuf_loader_new ();
        pixbuf = load_from_stream (loader, stream, cancellable, error);
        g_object_unref (loader);

        return pixbuf;
}

GdkPixbuf *
_gdk_pixbuf_new_from_resource_try_pixdata (const char *resource_path)
{
	gsize data_size;
	GBytes *bytes;

G_GNUC_BEGIN_IGNORE_DEPRECATIONS
	/* We specialize GdkPixdata files, making these a reference to the
	 * compiled-in resource data, whether uncompressed and mmap'ed, or
	 * compressed, and uncompressed on-the-fly.
         */
	if (g_resources_get_info  (resource_path, 0, &data_size, NULL, NULL) &&
	    data_size > sizeof(guint32) &&
	    (bytes = g_resources_lookup_data (resource_path, 0, NULL)) != NULL) {
		GdkPixbuf*pixbuf = NULL;
		const guint8 *stream = g_bytes_get_data (bytes, NULL);
		GdkPixdata pixdata;
		guint32 magic;

		magic = (stream[0] << 24) + (stream[1] << 16) + (stream[2] << 8) + stream[3];
		if (magic == GDK_PIXBUF_MAGIC_NUMBER &&
		    gdk_pixdata_deserialize (&pixdata, data_size, stream, NULL)) {
			pixbuf = gdk_pixbuf_from_pixdata (&pixdata, FALSE, NULL);
		}

		if (pixbuf) {
			/* Free the GBytes with the pixbuf */
			g_object_set_data_full (G_OBJECT (pixbuf), "gdk-pixbuf-resource-bytes", bytes, (GDestroyNotify) g_bytes_unref);
			return pixbuf;
		} else {
			g_bytes_unref (bytes);
		}
	}
G_GNUC_END_IGNORE_DEPRECATIONS

        return NULL;
}

/**
 * gdk_pixbuf_new_from_resource:
 * @resource_path: the path of the resource file
 * @error: Return location for an error
 *
 * Creates a new pixbuf by loading an image from an resource.
 *
 * The file format is detected automatically. If %NULL is returned, then
 * @error will be set.
 *
 * Return value: A newly-created pixbuf, or %NULL if any of several error
 * conditions occurred: the file could not be opened, the image format is
 * not supported, there was not enough memory to allocate the image buffer,
 * the stream contained invalid data, or the operation was cancelled.
 *
 * Since: 2.26
 **/
GdkPixbuf *
gdk_pixbuf_new_from_resource (const gchar  *resource_path,
			      GError      **error)
{
	GInputStream *stream;
	GdkPixbuf *pixbuf;

        pixbuf = _gdk_pixbuf_new_from_resource_try_pixdata (resource_path);
        if (pixbuf)
                return pixbuf;

	stream = g_resources_open_stream (resource_path, 0, error);
	if (stream == NULL)
		return NULL;

	pixbuf = gdk_pixbuf_new_from_stream (stream, NULL, error);
	g_object_unref (stream);
	return pixbuf;
}

/**
 * gdk_pixbuf_new_from_resource_at_scale:
 * @resource_path: the path of the resource file
 * @width: The width the image should have or -1 to not constrain the width
 * @height: The height the image should have or -1 to not constrain the height
 * @preserve_aspect_ratio: %TRUE to preserve the image's aspect ratio
 * @error: Return location for an error
 *
 * Creates a new pixbuf by loading an image from an resource.
 *
 * The file format is detected automatically. If %NULL is returned, then
 * @error will be set.
 *
 * The image will be scaled to fit in the requested size, optionally
 * preserving the image's aspect ratio. When preserving the aspect ratio,
 * a @width of -1 will cause the image to be scaled to the exact given
 * height, and a @height of -1 will cause the image to be scaled to the
 * exact given width. When not preserving aspect ratio, a @width or
 * @height of -1 means to not scale the image at all in that dimension.
 *
 * The stream is not closed.
 *
 * Return value: A newly-created pixbuf, or %NULL if any of several error
 * conditions occurred: the file could not be opened, the image format is
 * not supported, there was not enough memory to allocate the image buffer,
 * the stream contained invalid data, or the operation was cancelled.
 *
 * Since: 2.26
 */
GdkPixbuf *
gdk_pixbuf_new_from_resource_at_scale (const char *resource_path,
				       int         width,
				       int         height,
				       gboolean    preserve_aspect_ratio,
				       GError    **error)
{
	GInputStream *stream;
	GdkPixbuf *pixbuf;

	stream = g_resources_open_stream (resource_path, 0, error);
	if (stream == NULL)
		return NULL;

	pixbuf = gdk_pixbuf_new_from_stream_at_scale (stream, width, height, preserve_aspect_ratio, NULL, error);
	g_object_unref (stream);
	return pixbuf;
}

/**
 * gdk_pixbuf_new_from_stream_async:
 * @stream: a #GInputStream from which to load the pixbuf
 * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore
 * @callback: a #GAsyncReadyCallback to call when the pixbuf is loaded
 * @user_data: the data to pass to the callback function
 *
 * Creates a new pixbuf by asynchronously loading an image from an input stream.
 *
 * For more details see gdk_pixbuf_new_from_stream(), which is the synchronous
 * version of this function.
 *
 * When the operation is finished, @callback will be called in the main thread.
 * You can then call gdk_pixbuf_new_from_stream_finish() to get the result of the operation.
 *
 * Since: 2.24
 **/
void
gdk_pixbuf_new_from_stream_async (GInputStream        *stream,
				  GCancellable        *cancellable,
				  GAsyncReadyCallback  callback,
				  gpointer             user_data)
{
	GTask *task;

	g_return_if_fail (G_IS_INPUT_STREAM (stream));
	g_return_if_fail (callback != NULL);
	g_return_if_fail (!cancellable || G_IS_CANCELLABLE (cancellable));

	task = g_task_new (stream, cancellable, callback, user_data);
	g_task_set_source_tag (task, gdk_pixbuf_new_from_stream_async);
        g_task_set_task_data (task, gdk_pixbuf_loader_new (), g_object_unref);

        g_input_stream_read_bytes_async (stream,
                                         LOAD_BUFFER_SIZE, 
                                         G_PRIORITY_DEFAULT,
                                         cancellable,
                                         load_from_stream_async_cb,
                                         task);
}

/**
 * gdk_pixbuf_new_from_stream_finish:
 * @async_result: a #GAsyncResult
 * @error: a #GError, or %NULL
 *
 * Finishes an asynchronous pixbuf creation operation started with
 * gdk_pixbuf_new_from_stream_async().
 *
 * Return value: a #GdkPixbuf or %NULL on error. Free the returned
 * object with g_object_unref().
 *
 * Since: 2.24
 **/
GdkPixbuf *
gdk_pixbuf_new_from_stream_finish (GAsyncResult  *async_result,
				   GError       **error)
{
	GTask *task;

	g_return_val_if_fail (G_IS_TASK (async_result), NULL);
	g_return_val_if_fail (!error || (error && !*error), NULL);

	task = G_TASK (async_result);

	g_warn_if_fail (g_task_get_source_tag (task) == gdk_pixbuf_new_from_stream_async ||
			g_task_get_source_tag (task) == gdk_pixbuf_new_from_stream_at_scale_async);

	return g_task_propagate_pointer (task, error);
}

static void
info_cb (GdkPixbufLoader *loader, 
         int              width,
         int              height,
         gpointer         data)
{
        struct {
                GdkPixbufFormat *format;
                int width;
                int height;
        } *info = data;

        g_return_if_fail (width > 0 && height > 0);

        info->format = gdk_pixbuf_loader_get_format (loader);
        info->width = width;
        info->height = height;

        gdk_pixbuf_loader_set_size (loader, 0, 0);
}

/**
 * gdk_pixbuf_get_file_info:
 * @filename: (type filename): The name of the file to identify.
 * @width: (optional) (out): Return location for the width of the
 *     image, or %NULL
 * @height: (optional) (out): Return location for the height of the
 *     image, or %NULL
 * 
 * Parses an image file far enough to determine its format and size.
 * 
 * Returns: (nullable) (transfer none): A #GdkPixbufFormat describing
 *    the image format of the file or %NULL if the image format wasn't
 *    recognized. The return value is owned by #GdkPixbuf and should
 *    not be freed.
 *
 * Since: 2.4
 **/
GdkPixbufFormat *
gdk_pixbuf_get_file_info (const gchar  *filename,
                          gint         *width, 
                          gint         *height)
{
        GdkPixbufLoader *loader;
        guchar buffer[SNIFF_BUFFER_SIZE];
        int length;
        FILE *f;
        struct {
                GdkPixbufFormat *format;
                gint width;
                gint height;
        } info;

        g_return_val_if_fail (filename != NULL, NULL);

        f = g_fopen (filename, "rb");
        if (!f)
                return NULL;

        loader = _gdk_pixbuf_loader_new_with_filename (filename);

        info.format = NULL;
        info.width = -1;
        info.height = -1;
                
        g_signal_connect (loader, "size-prepared", G_CALLBACK (info_cb), &info);

        while (!feof (f) && !ferror (f)) {
                length = fread (buffer, 1, sizeof (buffer), f);
                if (length > 0) {
                        if (!gdk_pixbuf_loader_write (loader, buffer, length, NULL))
                                break;
                }
                if (info.format != NULL)
                        break;
        }

        fclose (f);
        gdk_pixbuf_loader_close (loader, NULL);
        g_object_unref (loader);

        if (width) 
                *width = info.width;
        if (height) 
                *height = info.height;

        return info.format;
}

typedef struct {
        gchar *filename;
        gint width;
        gint height;
} GetFileInfoAsyncData;

static void
get_file_info_async_data_free (GetFileInfoAsyncData *data)
{
        g_free (data->filename);
        g_slice_free (GetFileInfoAsyncData, data);
}

static void
get_file_info_thread (GTask                *task,
                      gpointer              source_object,
                      GetFileInfoAsyncData *data,
                      GCancellable         *cancellable)
{
        GdkPixbufFormat *format;

        format = gdk_pixbuf_get_file_info (data->filename, &data->width, &data->height);
        if (format == NULL) {
                g_task_return_new_error (task,
                                         GDK_PIXBUF_ERROR,
                                         GDK_PIXBUF_ERROR_UNKNOWN_TYPE,
                                         "Failed to recognize image format");
        } else {
                g_task_return_pointer (task,
                                       gdk_pixbuf_format_copy (format),
                                       (GDestroyNotify) gdk_pixbuf_format_free);
        }
}

/**
 * gdk_pixbuf_get_file_info_async:
 * @filename: (type filename): The name of the file to identify
 * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore
 * @callback: a #GAsyncReadyCallback to call when the file info is available
 * @user_data: the data to pass to the callback function
 *
 * Asynchronously parses an image file far enough to determine its
 * format and size.
 *
 * For more details see gdk_pixbuf_get_file_info(), which is the synchronous
 * version of this function.
 *
 * When the operation is finished, @callback will be called in the
 * main thread. You can then call gdk_pixbuf_get_file_info_finish() to
 * get the result of the operation.
 *
 * Since: 2.32
 **/
void
gdk_pixbuf_get_file_info_async  (const gchar          *filename,
                                 GCancellable         *cancellable,
                                 GAsyncReadyCallback   callback,
                                 gpointer              user_data)
{
        GetFileInfoAsyncData *data;
        GTask *task;

        g_return_if_fail (filename != NULL);
        g_return_if_fail (callback != NULL);
        g_return_if_fail (!cancellable || G_IS_CANCELLABLE (cancellable));

        data = g_slice_new0 (GetFileInfoAsyncData);
        data->filename = g_strdup (filename);

        task = g_task_new (NULL, cancellable, callback, user_data);
        g_task_set_return_on_cancel (task, TRUE);
        g_task_set_source_tag (task, gdk_pixbuf_get_file_info_async);
        g_task_set_task_data (task, data, (GDestroyNotify) get_file_info_async_data_free);
        g_task_run_in_thread (task, (GTaskThreadFunc) get_file_info_thread);
        g_object_unref (task);
}

/**
 * gdk_pixbuf_get_file_info_finish:
 * @async_result: a #GAsyncResult
 * @width: (out): Return location for the width of the image, or %NULL
 * @height: (out): Return location for the height of the image, or %NULL
 * @error: a #GError, or %NULL
 *
 * Finishes an asynchronous pixbuf parsing operation started with
 * gdk_pixbuf_get_file_info_async().
 *
 * Returns: (transfer none): A #GdkPixbufFormat describing the image
 *    format of the file or %NULL if the image format wasn't
 *    recognized. The return value is owned by GdkPixbuf and should
 *    not be freed.
 *
 * Since: 2.32
 **/
GdkPixbufFormat *
gdk_pixbuf_get_file_info_finish (GAsyncResult         *async_result,
                                 gint                 *width,
                                 gint                 *height,
                                 GError              **error)
{
        GetFileInfoAsyncData *data;
        GTask *task;

        g_return_val_if_fail (g_task_is_valid (async_result, NULL), NULL);

        task = G_TASK (async_result);

        g_return_val_if_fail (!error || (error && !*error), NULL);
        g_warn_if_fail (g_task_get_source_tag (task) == gdk_pixbuf_get_file_info_async);

        data = g_task_get_task_data (task);

        if (!g_task_had_error (task)) {
                if (width)
                        *width = data->width;
                if (height)
                        *height = data->height;
        }

        return g_task_propagate_pointer (task, error);
}

/**
 * gdk_pixbuf_new_from_xpm_data:
 * @data: (array zero-terminated=1): Pointer to inline XPM data.
 *
 * Creates a new pixbuf by parsing XPM data in memory.  This data is commonly
 * the result of including an XPM file into a program's C source.
 *
 * Return value: A newly-created pixbuf with a reference count of 1.
 **/
GdkPixbuf *
gdk_pixbuf_new_from_xpm_data (const char **data)
{
        GdkPixbuf *(* load_xpm_data) (const char **data);
        GdkPixbuf *pixbuf;
        GError *error = NULL;
        GdkPixbufModule *xpm_module;

        g_return_val_if_fail (data != NULL, NULL);

        xpm_module = _gdk_pixbuf_get_named_module ("xpm", &error);
        if (xpm_module == NULL) {
                g_warning ("Error loading XPM image loader: %s", error->message);
                g_error_free (error);
                return NULL;
        }

        if (!_gdk_pixbuf_load_module (xpm_module, &error)) {
                g_warning ("Error loading XPM image loader: %s", error->message);
                g_error_free (error);
                return NULL;
        }

        if (xpm_module->load_xpm_data == NULL) {
                g_warning ("gdk-pixbuf XPM module lacks XPM data capability");
                pixbuf = NULL;
        } else {
                load_xpm_data = xpm_module->load_xpm_data;
                pixbuf = (* load_xpm_data) (data);
        }

        return pixbuf;
}

static void
collect_save_options (va_list   opts,
                      gchar  ***keys,
                      gchar  ***vals)
{
  gchar *key;
  gchar *val;
  gchar *next;
  gint count;

  count = 0;
  *keys = NULL;
  *vals = NULL;
  
  next = va_arg (opts, gchar*);
  while (next)
    {
      key = next;
      val = va_arg (opts, gchar*);

      ++count;

      /* woo, slow */
      *keys = g_realloc (*keys, sizeof(gchar*) * (count + 1));
      *vals = g_realloc (*vals, sizeof(gchar*) * (count + 1));
      
      (*keys)[count-1] = g_strdup (key);
      (*vals)[count-1] = g_strdup (val);

      (*keys)[count] = NULL;
      (*vals)[count] = NULL;
      
      next = va_arg (opts, gchar*);
    }
}

static gboolean
save_to_file_callback (const gchar *buf,
                       gsize        count,
                       GError     **error,
                       gpointer     data)
{
        FILE *filehandle = data;
        gsize n;

        n = fwrite (buf, 1, count, filehandle);
        if (n != count) {
                gint save_errno = errno;
                g_set_error (error,
                             G_FILE_ERROR,
                             g_file_error_from_errno (save_errno),
                             _("Error writing to image file: %s"),
                             g_strerror (save_errno));
                return FALSE;
        }
        return TRUE;
}

static gboolean
gdk_pixbuf_real_save (GdkPixbuf     *pixbuf, 
                      FILE          *filehandle, 
                      const char    *type, 
                      gchar        **keys,
                      gchar        **values,
                      GError       **error)
{
        gboolean ret;
        GdkPixbufModule *image_module = NULL;       

        image_module = _gdk_pixbuf_get_named_module (type, error);

        if (image_module == NULL)
                return FALSE;
       
        if (!_gdk_pixbuf_load_module (image_module, error))
                return FALSE;

        if (image_module->save) {
                /* save normally */
                ret = (* image_module->save) (filehandle, pixbuf,
                                              keys, values,
                                              error);
        } else if (image_module->save_to_callback) {
                /* save with simple callback */
                ret = (* image_module->save_to_callback) (save_to_file_callback,
                                                          filehandle, pixbuf,
                                                          keys, values,
                                                          error);
        } else {
                /* can't save */
                g_set_error (error,
                             GDK_PIXBUF_ERROR,
                             GDK_PIXBUF_ERROR_UNSUPPORTED_OPERATION,
                             _("This build of gdk-pixbuf does not support saving the image format: %s"),
                             type);
                ret = FALSE;
        }

        return ret;
}

#define TMP_FILE_BUF_SIZE 4096

static gboolean
save_to_callback_with_tmp_file (GdkPixbufModule   *image_module,
                                GdkPixbuf         *pixbuf,
                                GdkPixbufSaveFunc  save_func,
                                gpointer           user_data,
                                gchar            **keys,
                                gchar            **values,
                                GError           **error)
{
        int fd;
        FILE *f = NULL;
        gboolean retval = FALSE;
        gchar *buf = NULL;
        gsize n;
        gchar *filename = NULL;

        buf = g_try_malloc (TMP_FILE_BUF_SIZE);
        if (buf == NULL) {
                g_set_error_literal (error,
                                     GDK_PIXBUF_ERROR,
                                     GDK_PIXBUF_ERROR_INSUFFICIENT_MEMORY,
                                     _("Insufficient memory to save image to callback"));
                goto end;
        }

        fd = g_file_open_tmp ("gdkpixbuf-save-tmp.XXXXXX", &filename, error);
        if (fd == -1)
                goto end;
        f = fdopen (fd, "wb+");
        if (f == NULL) {
                gint save_errno = errno;
                g_set_error_literal (error,
                                     G_FILE_ERROR,
                                     g_file_error_from_errno (save_errno),
                                     _("Failed to open temporary file"));
                goto end;
        }

        retval = (image_module->save) (f, pixbuf, keys, values, error);
        if (!retval)
                goto end;

        rewind (f);
        for (;;) {
                n = fread (buf, 1, TMP_FILE_BUF_SIZE, f);
                if (n > 0) {
                        if (!save_func (buf, n, error, user_data))
                                goto end;
                }
                if (n != TMP_FILE_BUF_SIZE) 
                        break;
        }
        if (ferror (f)) {
                gint save_errno = errno;
                g_set_error_literal (error,
                                     G_FILE_ERROR,
                                     g_file_error_from_errno (save_errno),
                                     _("Failed to read from temporary file"));
                goto end;
        }
        retval = TRUE;

 end:
        /* cleanup and return retval */
        if (f)
                fclose (f);
        if (filename) {
                g_unlink (filename);
                g_free (filename);
        }
        g_free (buf);

        return retval;
}

static gboolean
gdk_pixbuf_real_save_to_callback (GdkPixbuf         *pixbuf,
                                  GdkPixbufSaveFunc  save_func,
                                  gpointer           user_data,
                                  const char        *type, 
                                  gchar            **keys,
                                  gchar            **values,
                                  GError           **error)
{
        gboolean ret;
        GdkPixbufModule *image_module = NULL;       

        image_module = _gdk_pixbuf_get_named_module (type, error);

        if (image_module == NULL)
                return FALSE;
       
        if (!_gdk_pixbuf_load_module (image_module, error))
                return FALSE;

        if (image_module->save_to_callback) {
                /* save normally */
                ret = (* image_module->save_to_callback) (save_func, user_data, 
                                                          pixbuf, keys, values,
                                                          error);
        } else if (image_module->save) {
                /* use a temporary file */
                ret = save_to_callback_with_tmp_file (image_module, pixbuf,
                                                      save_func, user_data, 
                                                      keys, values,
                                                      error);
        } else {
                /* can't save */
                g_set_error (error,
                             GDK_PIXBUF_ERROR,
                             GDK_PIXBUF_ERROR_UNSUPPORTED_OPERATION,
                             _("This build of gdk-pixbuf does not support saving the image format: %s"),
                             type);
                ret = FALSE;
        }

        return ret;
}

 
/**
 * gdk_pixbuf_save:
 * @pixbuf: a #GdkPixbuf.
 * @filename: (type filename): name of file to save.
 * @type: name of file format.
 * @error: (allow-none): return location for error, or %NULL
 * @...: list of key-value save options, followed by %NULL
 *
 * Saves pixbuf to a file in format @type. By default, "jpeg", "png", "ico" 
 * and "bmp" are possible file formats to save in, but more formats may be
 * installed. The list of all writable formats can be determined in the 
 * following way:
 *
 * |[
 * void add_if_writable (GdkPixbufFormat *data, GSList **list)
 * {
 *   if (gdk_pixbuf_format_is_writable (data))
 *     *list = g_slist_prepend (*list, data);
 * }
 * 
 * GSList *formats = gdk_pixbuf_get_formats ();
 * GSList *writable_formats = NULL;
 * g_slist_foreach (formats, add_if_writable, &writable_formats);
 * g_slist_free (formats);
 * ]|
 *
 * If @error is set, %FALSE will be returned. Possible errors include 
 * those in the #GDK_PIXBUF_ERROR domain and those in the #G_FILE_ERROR domain.
 *
 * The variable argument list should be %NULL-terminated; if not empty,
 * it should contain pairs of strings that modify the save
 * parameters. For example:
 * |[
 * gdk_pixbuf_save (pixbuf, handle, "jpeg", &error, "quality", "100", NULL);
 * ]|
 *
 * Currently only few parameters exist. JPEG images can be saved with a
 * "quality" parameter; its value should be in the range [0,100]. JPEG
 * and PNG density can be set by setting the "x-dpi" and "y-dpi" parameters
 * to the appropriate values in dots per inch.
 *
 * Text chunks can be attached to PNG images by specifying parameters of
 * the form "tEXt::key", where key is an ASCII string of length 1-79.
 * The values are UTF-8 encoded strings. The PNG compression level can
 * be specified using the "compression" parameter; it's value is in an
 * integer in the range of [0,9].
 *
 * ICC color profiles can also be embedded into PNG, JPEG and TIFF images.
 * The "icc-profile" value should be the complete ICC profile encoded
 * into base64.
 *
 * |[
 * gchar *contents;
 * gchar *contents_encode;
 * gsize length;
 * g_file_get_contents ("/home/hughsie/.color/icc/L225W.icm", &contents, &length, NULL);
 * contents_encode = g_base64_encode ((const guchar *) contents, length);
 * gdk_pixbuf_save (pixbuf, handle, "png", &error, "icc-profile", contents_encode, NULL);
 * ]|
 *
 * TIFF images recognize: (1) a "bits-per-sample" option (integer) which
 * can be either 1 for saving bi-level CCITTFAX4 images, or 8 for saving
 * 8-bits per sample; (2) a "compression" option (integer) which can be
 * 1 for no compression, 2 for Huffman, 5 for LZW, 7 for JPEG and 8 for
 * DEFLATE (see the libtiff documentation and tiff.h for all supported
 * codec values); (3) an "icc-profile" option (zero-terminated string)
 * containing a base64 encoded ICC color profile.
 *
 * ICO images can be saved in depth 16, 24, or 32, by using the "depth"
 * parameter. When the ICO saver is given "x_hot" and "y_hot" parameters,
 * it produces a CUR instead of an ICO.
 *
 * Return value: whether an error was set
 **/
gboolean
gdk_pixbuf_save (GdkPixbuf  *pixbuf, 
                 const char *filename, 
                 const char *type, 
                 GError    **error,
                 ...)
{
        gchar **keys = NULL;
        gchar **values = NULL;
        va_list args;
        gboolean result;

        g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
        
        va_start (args, error);
        
        collect_save_options (args, &keys, &values);
        
        va_end (args);

        result = gdk_pixbuf_savev (pixbuf, filename, type,
                                   keys, values,
                                   error);

        g_strfreev (keys);
        g_strfreev (values);

        return result;
}

/**
 * gdk_pixbuf_savev:
 * @pixbuf: a #GdkPixbuf.
 * @filename: (type filename): name of file to save.
 * @type: name of file format.
 * @option_keys: (array zero-terminated=1): name of options to set, %NULL-terminated
 * @option_values: (array zero-terminated=1): values for named options
 * @error: (allow-none): return location for error, or %NULL
 *
 * Saves pixbuf to a file in @type, which is currently "jpeg", "png", "tiff", "ico" or "bmp".
 * If @error is set, %FALSE will be returned. 
 * See gdk_pixbuf_save () for more details.
 *
 * Return value: whether an error was set
 **/

gboolean
gdk_pixbuf_savev (GdkPixbuf  *pixbuf, 
                  const char *filename, 
                  const char *type,
                  char      **option_keys,
                  char      **option_values,
                  GError    **error)
{
        FILE *f = NULL;
        gboolean result;
       
        g_return_val_if_fail (GDK_IS_PIXBUF (pixbuf), FALSE);
        g_return_val_if_fail (gdk_pixbuf_get_width (pixbuf) >= 0, FALSE);
        g_return_val_if_fail (gdk_pixbuf_get_height (pixbuf) >= 0, FALSE);
        g_return_val_if_fail (gdk_pixbuf_get_n_channels (pixbuf) >= 0, FALSE);
        g_return_val_if_fail (filename != NULL, FALSE);
        g_return_val_if_fail (type != NULL, FALSE);
        g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
       
        f = g_fopen (filename, "wb");
        
        if (f == NULL) {
                gint save_errno = errno;
                gchar *display_name = g_filename_display_name (filename);
                g_set_error (error,
                             G_FILE_ERROR,
                             g_file_error_from_errno (save_errno),
                             _("Failed to open “%s” for writing: %s"),
                             display_name,
                             g_strerror (save_errno));
                g_free (display_name);
                return FALSE;
        }

       
       result = gdk_pixbuf_real_save (pixbuf, f, type,
                                      option_keys, option_values,
                                      error);
       
       
       if (!result) {
               g_return_val_if_fail (error == NULL || *error != NULL, FALSE);
               fclose (f);
               g_unlink (filename);
               return FALSE;
       }

       if (fclose (f) < 0) {
               gint save_errno = errno;
               gchar *display_name = g_filename_display_name (filename);
               g_set_error (error,
                            G_FILE_ERROR,
                            g_file_error_from_errno (save_errno),
                            _("Failed to close “%s” while writing image, all data may not have been saved: %s"),
                            display_name,
                            g_strerror (save_errno));
               g_free (display_name);
               return FALSE;
       }
       
       return TRUE;
}

#ifdef G_OS_WIN32

/**
 * gdk_pixbuf_savev_utf8:
 * @pixbuf: a #GdkPixbuf.
 * @filename: name of file to save.
 * @type: name of file format.
 * @option_keys: (array zero-terminated=1): name of options to set, %NULL-terminated
 * @option_values: (array zero-terminated=1): values for named options
 * @error: (allow-none): return location for error, or %NULL
 *
 * Same as gdk_pixbuf_savev()
 *
 * Return value: whether an error was set
 **/
gboolean
gdk_pixbuf_savev_utf8 (GdkPixbuf  *pixbuf,
                       const char *filename,
                       const char *type,
                       char      **option_keys,
                       char      **option_values,
                       GError    **error)
{
    return gdk_pixbuf_savev (pixbuf, filename, type, option_keys,
                             option_values, error);
}

#endif

/**
 * gdk_pixbuf_save_to_callback:
 * @pixbuf: a #GdkPixbuf.
 * @save_func: (scope call): a function that is called to save each block of data that
 *   the save routine generates.
 * @user_data: user data to pass to the save function.
 * @type: name of file format.
 * @error: (allow-none): return location for error, or %NULL
 * @...: list of key-value save options
 *
 * Saves pixbuf in format @type by feeding the produced data to a 
 * callback. Can be used when you want to store the image to something 
 * other than a file, such as an in-memory buffer or a socket.  
 * If @error is set, %FALSE will be returned. Possible errors
 * include those in the #GDK_PIXBUF_ERROR domain and whatever the save
 * function generates.
 *
 * See gdk_pixbuf_save() for more details.
 *
 * Return value: whether an error was set
 *
 * Since: 2.4
 **/
gboolean
gdk_pixbuf_save_to_callback    (GdkPixbuf  *pixbuf,
                                GdkPixbufSaveFunc save_func,
                                gpointer user_data,
                                const char *type, 
                                GError    **error,
                                ...)
{
        gchar **keys = NULL;
        gchar **values = NULL;
        va_list args;
        gboolean result;
        
        g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
        
        va_start (args, error);
        
        collect_save_options (args, &keys, &values);
        
        va_end (args);

        result = gdk_pixbuf_save_to_callbackv (pixbuf, save_func, user_data,
                                               type, keys, values,
                                               error);

        g_strfreev (keys);
        g_strfreev (values);

        return result;
}

/**
 * gdk_pixbuf_save_to_callbackv:
 * @pixbuf: a #GdkPixbuf.
 * @save_func: (scope call): a function that is called to save each block of data that
 *   the save routine generates.
 * @user_data: (closure): user data to pass to the save function.
 * @type: name of file format.
 * @option_keys: (array zero-terminated=1) (element-type utf8): name of options to set, %NULL-terminated
 * @option_values: (array zero-terminated=1) (element-type utf8): values for named options
 * @error: (allow-none): return location for error, or %NULL
 *
 * Saves pixbuf to a callback in format @type, which is currently "jpeg",
 * "png", "tiff", "ico" or "bmp".  If @error is set, %FALSE will be returned. See
 * gdk_pixbuf_save_to_callback () for more details.
 *
 * Return value: whether an error was set
 *
 * Since: 2.4
 **/
gboolean
gdk_pixbuf_save_to_callbackv   (GdkPixbuf  *pixbuf, 
                                GdkPixbufSaveFunc save_func,
                                gpointer user_data,
                                const char *type,
                                char      **option_keys,
                                char      **option_values,
                                GError    **error)
{
        gboolean result;
        
        g_return_val_if_fail (GDK_IS_PIXBUF (pixbuf), FALSE);
        g_return_val_if_fail (gdk_pixbuf_get_width (pixbuf) >= 0, FALSE);
        g_return_val_if_fail (gdk_pixbuf_get_height (pixbuf) >= 0, FALSE);
        g_return_val_if_fail (gdk_pixbuf_get_n_channels (pixbuf) >= 0, FALSE);
        g_return_val_if_fail (save_func != NULL, FALSE);
        g_return_val_if_fail (type != NULL, FALSE);
        g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
       
       result = gdk_pixbuf_real_save_to_callback (pixbuf,
                                                  save_func, user_data, type,
                                                  option_keys, option_values,
                                                  error);
       
       if (!result) {
               g_return_val_if_fail (error == NULL || *error != NULL, FALSE);
               return FALSE;
       }

       return TRUE;
}

/**
 * gdk_pixbuf_save_to_buffer:
 * @pixbuf: a #GdkPixbuf.
 * @buffer: (array length=buffer_size) (out) (element-type guint8): location to receive a pointer
 *   to the new buffer.
 * @buffer_size: location to receive the size of the new buffer.
 * @type: name of file format.
 * @error: (allow-none): return location for error, or %NULL
 * @...: list of key-value save options
 *
 * Saves pixbuf to a new buffer in format @type, which is currently "jpeg",
 * "png", "tiff", "ico" or "bmp".  This is a convenience function that uses
 * gdk_pixbuf_save_to_callback() to do the real work. Note that the buffer 
 * is not nul-terminated and may contain embedded  nuls.
 * If @error is set, %FALSE will be returned and @buffer will be set to
 * %NULL. Possible errors include those in the #GDK_PIXBUF_ERROR
 * domain.
 *
 * See gdk_pixbuf_save() for more details.
 *
 * Return value: whether an error was set
 *
 * Since: 2.4
 **/
gboolean
gdk_pixbuf_save_to_buffer      (GdkPixbuf  *pixbuf,
                                gchar     **buffer,
                                gsize      *buffer_size,
                                const char *type, 
                                GError    **error,
                                ...)
{
        gchar **keys = NULL;
        gchar **values = NULL;
        va_list args;
        gboolean result;
        
        g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
        
        va_start (args, error);
        
        collect_save_options (args, &keys, &values);
        
        va_end (args);

        result = gdk_pixbuf_save_to_bufferv (pixbuf, buffer, buffer_size,
                                             type, keys, values,
                                             error);

        g_strfreev (keys);
        g_strfreev (values);

        return result;
}

struct SaveToBufferData {
        gchar *buffer;
        gsize len, max;
};

static gboolean
save_to_buffer_callback (const gchar *data,
                         gsize count,
                         GError **error,
                         gpointer user_data)
{
        struct SaveToBufferData *sdata = user_data;
        gchar *new_buffer;
        gsize new_max;

        if (sdata->len + count > sdata->max) {
                new_max = MAX (sdata->max*2, sdata->len + count);
                new_buffer = g_try_realloc (sdata->buffer, new_max);
                if (!new_buffer) {
                        g_set_error_literal (error,
                                             GDK_PIXBUF_ERROR,
                                             GDK_PIXBUF_ERROR_INSUFFICIENT_MEMORY,
                                             _("Insufficient memory to save image into a buffer"));
                        return FALSE;
                }
                sdata->buffer = new_buffer;
                sdata->max = new_max;
        }
        memcpy (sdata->buffer + sdata->len, data, count);
        sdata->len += count;
        return TRUE;
}

/**
 * gdk_pixbuf_save_to_bufferv:
 * @pixbuf: a #GdkPixbuf.
 * @buffer: (array length=buffer_size) (out) (element-type guint8):
 *   location to receive a pointer to the new buffer.
 * @buffer_size: location to receive the size of the new buffer.
 * @type: name of file format.
 * @option_keys: (array zero-terminated=1): name of options to set, %NULL-terminated
 * @option_values: (array zero-terminated=1): values for named options
 * @error: (allow-none): return location for error, or %NULL
 *
 * Saves pixbuf to a new buffer in format @type, which is currently "jpeg",
 * "tiff", "png", "ico" or "bmp".  See gdk_pixbuf_save_to_buffer() 
 * for more details.
 *
 * Return value: whether an error was set
 *
 * Since: 2.4
 **/
gboolean
gdk_pixbuf_save_to_bufferv     (GdkPixbuf  *pixbuf,
                                gchar     **buffer,
                                gsize      *buffer_size,
                                const char *type, 
                                char      **option_keys,
                                char      **option_values,
                                GError    **error)
{
        static const gint initial_max = 1024;
        struct SaveToBufferData sdata;

        *buffer = NULL;
        *buffer_size = 0;

        sdata.buffer = g_try_malloc (initial_max);
        sdata.max = initial_max;
        sdata.len = 0;
        if (!sdata.buffer) {
                g_set_error_literal (error,
                                     GDK_PIXBUF_ERROR,
                                     GDK_PIXBUF_ERROR_INSUFFICIENT_MEMORY,
                                     _("Insufficient memory to save image into a buffer"));
                return FALSE;
        }

        if (!gdk_pixbuf_save_to_callbackv (pixbuf,
                                           save_to_buffer_callback, &sdata,
                                           type, option_keys, option_values,
                                           error)) {
                g_free (sdata.buffer);
                return FALSE;
        }

        *buffer = sdata.buffer;
        *buffer_size = sdata.len;
        return TRUE;
}

typedef struct {
        GOutputStream *stream;
        GCancellable  *cancellable;
} SaveToStreamData;

static gboolean
save_to_stream (const gchar  *buffer,
                gsize         count,
                GError      **error,
                gpointer      data)
{
        SaveToStreamData *sdata = (SaveToStreamData *)data;
        gsize remaining;
        gssize written;
        GError *my_error = NULL;

        remaining = count;
        written = 0;
        while (remaining > 0) {
                buffer += written;
                remaining -= written;
                written = g_output_stream_write (sdata->stream, 
                                                 buffer, remaining, 
                                                 sdata->cancellable, 
                                                 &my_error);
                if (written < 0) {
                        if (!my_error) {
                                g_set_error_literal (error,
                                                     G_IO_ERROR, 0,
                                                     _("Error writing to image stream"));
                        }
                        else {
                                g_propagate_error (error, my_error);
                        }
                        return FALSE;
                }
        }

        return TRUE;
}

/**
 * gdk_pixbuf_save_to_streamv:
 * @pixbuf: a #GdkPixbuf
 * @stream: a #GOutputStream to save the pixbuf to
 * @type: name of file format
 * @option_keys: (array zero-terminated=1): name of options to set, %NULL-terminated
 * @option_values: (array zero-terminated=1): values for named options
 * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore
 * @error: (allow-none): return location for error, or %NULL
 *
 * Saves @pixbuf to an output stream.
 *
 * Supported file formats are currently "jpeg", "tiff", "png", "ico" or
 * "bmp". See gdk_pixbuf_save_to_stream() for more details.
 *
 * Returns: %TRUE if the pixbuf was saved successfully, %FALSE if an
 *     error was set.
 *
 * Since: 2.36
 */
gboolean
gdk_pixbuf_save_to_streamv (GdkPixbuf      *pixbuf,
                            GOutputStream  *stream,
                            const char     *type,
                            char          **option_keys,
                            char          **option_values,
                            GCancellable   *cancellable,
                            GError        **error)
{
        SaveToStreamData data;

        data.stream = stream;
        data.cancellable = cancellable;

        return gdk_pixbuf_save_to_callbackv (pixbuf, save_to_stream,
                                             &data, type,
                                             option_keys, option_values,
                                             error);
}

/**
 * gdk_pixbuf_save_to_stream:
 * @pixbuf: a #GdkPixbuf
 * @stream: a #GOutputStream to save the pixbuf to
 * @type: name of file format
 * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore
 * @error: (allow-none): return location for error, or %NULL
 * @...: list of key-value save options
 *
 * Saves @pixbuf to an output stream.
 *
 * Supported file formats are currently "jpeg", "tiff", "png", "ico" or 
 * "bmp". See gdk_pixbuf_save_to_buffer() for more details.
 *
 * The @cancellable can be used to abort the operation from another 
 * thread. If the operation was cancelled, the error %G_IO_ERROR_CANCELLED 
 * will be returned. Other possible errors are in the #GDK_PIXBUF_ERROR 
 * and %G_IO_ERROR domains. 
 *
 * The stream is not closed.
 *
 * Returns: %TRUE if the pixbuf was saved successfully, %FALSE if an
 *     error was set.
 *
 * Since: 2.14
 */
gboolean
gdk_pixbuf_save_to_stream (GdkPixbuf      *pixbuf,
                           GOutputStream  *stream,
                           const char     *type,
                           GCancellable   *cancellable,
                           GError        **error,
                           ...)
{
        gboolean res;
        gchar **keys = NULL;
        gchar **values = NULL;
        va_list args;

        va_start (args, error);
        collect_save_options (args, &keys, &values);
        va_end (args);

        res = gdk_pixbuf_save_to_streamv (pixbuf, stream, type,
                                          keys, values,
                                          cancellable, error);

        g_strfreev (keys);
        g_strfreev (values);

        return res;
}

typedef struct {
	GOutputStream *stream;
	gchar *type;
	gchar **keys;
	gchar **values;
} SaveToStreamAsyncData;

static void
save_to_stream_async_data_free (SaveToStreamAsyncData *data)
{
	if (data->stream)
		g_object_unref (data->stream);
	g_strfreev (data->keys);
	g_strfreev (data->values);
	g_free (data->type);
	g_slice_free (SaveToStreamAsyncData, data);
}

static void
save_to_stream_thread (GTask                 *task,
		       GdkPixbuf             *pixbuf,
		       SaveToStreamAsyncData *data,
		       GCancellable          *cancellable)
{
	SaveToStreamData sync_data;
	gboolean retval;
	GError *error = NULL;

	sync_data.stream = data->stream;
	sync_data.cancellable = cancellable;

	retval = gdk_pixbuf_save_to_callbackv (pixbuf, save_to_stream,
					       &sync_data, data->type,
					       data->keys, data->values,
					       &error);

	if (retval == FALSE) {
		g_task_return_error (task, error);
	} else {
		g_task_return_boolean (task, TRUE);
	}
}

/**
 * gdk_pixbuf_save_to_streamv_async:
 * @pixbuf: a #GdkPixbuf
 * @stream: a #GOutputStream to which to save the pixbuf
 * @type: name of file format
 * @option_keys: (array zero-terminated=1): name of options to set, %NULL-terminated
 * @option_values: (array zero-terminated=1): values for named options
 * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore
 * @callback: a #GAsyncReadyCallback to call when the pixbuf is saved
 * @user_data: the data to pass to the callback function
 *
 * Saves @pixbuf to an output stream asynchronously.
 *
 * For more details see gdk_pixbuf_save_to_streamv(), which is the synchronous
 * version of this function.
 *
 * When the operation is finished, @callback will be called in the main thread.
 * You can then call gdk_pixbuf_save_to_stream_finish() to get the result of the operation.
 *
 * Since: 2.36
 **/
void
gdk_pixbuf_save_to_streamv_async (GdkPixbuf           *pixbuf,
                                  GOutputStream       *stream,
                                  const gchar         *type,
                                  gchar              **option_keys,
                                  gchar              **option_values,
                                  GCancellable        *cancellable,
                                  GAsyncReadyCallback  callback,
                                  gpointer             user_data)
{
        GTask *task;
        SaveToStreamAsyncData *data;

        g_return_if_fail (GDK_IS_PIXBUF (pixbuf));
        g_return_if_fail (gdk_pixbuf_get_width (pixbuf) >= 0);
        g_return_if_fail (gdk_pixbuf_get_height (pixbuf) >= 0);
        g_return_if_fail (gdk_pixbuf_get_n_channels (pixbuf) >= 0);
        g_return_if_fail (G_IS_OUTPUT_STREAM (stream));
        g_return_if_fail (type != NULL);
        g_return_if_fail (callback != NULL);
        g_return_if_fail (!cancellable || G_IS_CANCELLABLE (cancellable));

        data = g_slice_new (SaveToStreamAsyncData);
        data->stream = g_object_ref (stream);
        data->type = g_strdup (type);
        data->keys = g_strdupv (option_keys);
        data->values = g_strdupv (option_values);

        task = g_task_new (pixbuf, cancellable, callback, user_data);
        g_task_set_source_tag (task, gdk_pixbuf_save_to_streamv_async);
        g_task_set_task_data (task, data, (GDestroyNotify) save_to_stream_async_data_free);
        g_task_run_in_thread (task, (GTaskThreadFunc) save_to_stream_thread);
        g_object_unref (task);
}

/**
 * gdk_pixbuf_save_to_stream_async:
 * @pixbuf: a #GdkPixbuf
 * @stream: a #GOutputStream to which to save the pixbuf
 * @type: name of file format
 * @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore
 * @callback: a #GAsyncReadyCallback to call when the pixbuf is saved
 * @user_data: the data to pass to the callback function
 * @...: list of key-value save options
 *
 * Saves @pixbuf to an output stream asynchronously.
 *
 * For more details see gdk_pixbuf_save_to_stream(), which is the synchronous
 * version of this function.
 *
 * When the operation is finished, @callback will be called in the main thread.
 * You can then call gdk_pixbuf_save_to_stream_finish() to get the result of the operation.
 *
 * Since: 2.24
 **/
void
gdk_pixbuf_save_to_stream_async (GdkPixbuf           *pixbuf,
				 GOutputStream       *stream,
				 const gchar         *type,
				 GCancellable        *cancellable,
				 GAsyncReadyCallback  callback,
				 gpointer             user_data,
				 ...)
{
        gchar **keys = NULL;
        gchar **values = NULL;
        va_list args;

        g_return_if_fail (GDK_IS_PIXBUF (pixbuf));
        g_return_if_fail (gdk_pixbuf_get_width (pixbuf) >= 0);
        g_return_if_fail (gdk_pixbuf_get_height (pixbuf) >= 0);
        g_return_if_fail (gdk_pixbuf_get_n_channels (pixbuf) >= 0);
        g_return_if_fail (G_IS_OUTPUT_STREAM (stream));
        g_return_if_fail (type != NULL);
        g_return_if_fail (callback != NULL);
        g_return_if_fail (!cancellable || G_IS_CANCELLABLE (cancellable));

        va_start (args, user_data);
        collect_save_options (args, &keys, &values);
        va_end (args);

        gdk_pixbuf_save_to_streamv_async (pixbuf, stream, type,
                                          keys, values,
                                          cancellable, callback, user_data);
        g_strfreev (keys);
        g_strfreev (values);
}

/**
 * gdk_pixbuf_save_to_stream_finish:
 * @async_result: a #GAsyncResult
 * @error: a #GError, or %NULL
 *
 * Finishes an asynchronous pixbuf save operation started with
 * gdk_pixbuf_save_to_stream_async().
 *
 * Return value: %TRUE if the pixbuf was saved successfully, %FALSE if an error was set.
 *
 * Since: 2.24
 **/
gboolean
gdk_pixbuf_save_to_stream_finish (GAsyncResult  *async_result,
				  GError       **error)
{
	GTask *task;

	/* Can not use g_task_is_valid because our GTask has a
	 * source_object which is not available to us anymore.
	 */
	g_return_val_if_fail (G_IS_TASK (async_result), FALSE);

	task = G_TASK (async_result);

	g_return_val_if_fail (!error || (error && !*error), FALSE);
	g_warn_if_fail (g_task_get_source_tag (task) == gdk_pixbuf_save_to_stream_async ||
			g_task_get_source_tag (task) == gdk_pixbuf_save_to_streamv_async);

	return g_task_propagate_boolean (task, error);
}

/**
 * gdk_pixbuf_format_get_name:
 * @format: a #GdkPixbufFormat
 *
 * Returns the name of the format.
 * 
 * Return value: the name of the format. 
 *
 * Since: 2.2
 */
gchar *
gdk_pixbuf_format_get_name (GdkPixbufFormat *format)
{
        g_return_val_if_fail (format != NULL, NULL);

        return g_strdup (format->name);
}

/**
 * gdk_pixbuf_format_get_description:
 * @format: a #GdkPixbufFormat
 *
 * Returns a description of the format.
 * 
 * Return value: a description of the format.
 *
 * Since: 2.2
 */
gchar *
gdk_pixbuf_format_get_description (GdkPixbufFormat *format)
{
        gchar *domain;
        const gchar *description;
        g_return_val_if_fail (format != NULL, NULL);

        if (format->domain != NULL) 
                domain = format->domain;
        else 
                domain = GETTEXT_PACKAGE;
        description = g_dgettext (domain, format->description);

        return g_strdup (description);
}

/**
 * gdk_pixbuf_format_get_mime_types:
 * @format: a #GdkPixbufFormat
 *
 * Returns the mime types supported by the format.
 * 
 * Return value: (transfer full): a %NULL-terminated array of mime types which must be freed with 
 * g_strfreev() when it is no longer needed.
 *
 * Since: 2.2
 */
gchar **
gdk_pixbuf_format_get_mime_types (GdkPixbufFormat *format)
{
        g_return_val_if_fail (format != NULL, NULL);

        return g_strdupv (format->mime_types);
}

/**
 * gdk_pixbuf_format_get_extensions:
 * @format: a #GdkPixbufFormat
 *
 * Returns the filename extensions typically used for files in the 
 * given format.
 * 
 * Return value: (transfer full): a %NULL-terminated array of filename extensions which must be
 * freed with g_strfreev() when it is no longer needed.
 *
 * Since: 2.2
 */
gchar **
gdk_pixbuf_format_get_extensions (GdkPixbufFormat *format)
{
        g_return_val_if_fail (format != NULL, NULL);

        return g_strdupv (format->extensions);
}

/**
 * gdk_pixbuf_format_is_writable:
 * @format: a #GdkPixbufFormat
 *
 * Returns whether pixbufs can be saved in the given format.
 * 
 * Return value: whether pixbufs can be saved in the given format.
 *
 * Since: 2.2
 */
gboolean
gdk_pixbuf_format_is_writable (GdkPixbufFormat *format)
{
        g_return_val_if_fail (format != NULL, FALSE);

        return (format->flags & GDK_PIXBUF_FORMAT_WRITABLE) != 0;
}

/**
 * gdk_pixbuf_format_is_scalable:
 * @format: a #GdkPixbufFormat
 *
 * Returns whether this image format is scalable. If a file is in a 
 * scalable format, it is preferable to load it at the desired size, 
 * rather than loading it at the default size and scaling the 
 * resulting pixbuf to the desired size.
 * 
 * Return value: whether this image format is scalable.
 *
 * Since: 2.6
 */
gboolean
gdk_pixbuf_format_is_scalable (GdkPixbufFormat *format)
{
        g_return_val_if_fail (format != NULL, FALSE);

        return (format->flags & GDK_PIXBUF_FORMAT_SCALABLE) != 0;
}

/**
 * gdk_pixbuf_format_is_disabled:
 * @format: a #GdkPixbufFormat
 *
 * Returns whether this image format is disabled. See
 * gdk_pixbuf_format_set_disabled().
 * 
 * Return value: whether this image format is disabled.
 *
 * Since: 2.6
 */
gboolean   
gdk_pixbuf_format_is_disabled (GdkPixbufFormat *format)
{
        g_return_val_if_fail (format != NULL, FALSE);

        return format->disabled;        
}

/**
 * gdk_pixbuf_format_set_disabled:
 * @format: a #GdkPixbufFormat
 * @disabled: %TRUE to disable the format @format
 *
 * Disables or enables an image format. If a format is disabled, 
 * gdk-pixbuf won't use the image loader for this format to load 
 * images. Applications can use this to avoid using image loaders 
 * with an inappropriate license, see gdk_pixbuf_format_get_license().
 *
 * Since: 2.6
 */
void 
gdk_pixbuf_format_set_disabled (GdkPixbufFormat *format,
                                gboolean         disabled)
{
        g_return_if_fail (format != NULL);
        
        format->disabled = disabled != FALSE;
}

/**
 * gdk_pixbuf_format_get_license:
 * @format: a #GdkPixbufFormat
 *
 * Returns information about the license of the image loader for the format. The
 * returned string should be a shorthand for a wellknown license, e.g. "LGPL",
 * "GPL", "QPL", "GPL/QPL", or "other" to indicate some other license.  This
 * string should be freed with g_free() when it's no longer needed.
 *
 * Returns: a string describing the license of @format. 
 *
 * Since: 2.6
 */
gchar*
gdk_pixbuf_format_get_license (GdkPixbufFormat *format)
{
        g_return_val_if_fail (format != NULL, NULL);

        return g_strdup (format->license);
}

GdkPixbufFormat *
_gdk_pixbuf_get_format (GdkPixbufModule *module)
{
        g_return_val_if_fail (module != NULL, NULL);

        return module->info;
}

/**
 * gdk_pixbuf_get_formats:
 *
 * Obtains the available information about the image formats supported
 * by GdkPixbuf.
 *
 * Returns: (transfer container) (element-type GdkPixbufFormat): A list of
 * #GdkPixbufFormats describing the supported image formats. The list should
 * be freed when it is no longer needed, but the structures themselves are
 * owned by #GdkPixbuf and should not be freed.
 *
 * Since: 2.2
 */
GSList *
gdk_pixbuf_get_formats (void)
{
        GSList *result = NULL;
        GSList *modules;

        for (modules = get_file_formats (); modules; modules = g_slist_next (modules)) {
                GdkPixbufModule *module = (GdkPixbufModule *)modules->data;
                GdkPixbufFormat *info = _gdk_pixbuf_get_format (module);
                result = g_slist_prepend (result, info);
        }

        return result;
}

/**
 * gdk_pixbuf_format_copy:
 * @format: a #GdkPixbufFormat
 *
 * Creates a copy of @format
 *
 * Return value: the newly allocated copy of a #GdkPixbufFormat. Use
 *   gdk_pixbuf_format_free() to free the resources when done
 *
 * Since: 2.22
 */
GdkPixbufFormat *
gdk_pixbuf_format_copy (const GdkPixbufFormat *format)
{
        if (G_LIKELY (format != NULL))
                return g_slice_dup (GdkPixbufFormat, format);

        return NULL;
}

/**
 * gdk_pixbuf_format_free:
 * @format: a #GdkPixbufFormat
 *
 * Frees the resources allocated when copying a #GdkPixbufFormat
 * using gdk_pixbuf_format_copy()
 *
 * Since: 2.22
 */
void
gdk_pixbuf_format_free (GdkPixbufFormat *format)
{
        if (G_LIKELY (format != NULL))
                g_slice_free (GdkPixbufFormat, format);
}

/**
 * gdk_pixbuf_format_is_save_option_supported:
 * @format: a #GdkPixbufFormat
 * @option_key: the name of an option
 *
 * Returns %TRUE if the save option specified by @option_key is supported when
 * saving a pixbuf using the module implementing @format.
 * See gdk_pixbuf_save() for more information about option keys.
 *
 * Returns: %TRUE if the specified option is supported
 *
 * Since: 2.36
 */
gboolean
gdk_pixbuf_format_is_save_option_supported (GdkPixbufFormat *format,
                                            const gchar *option_key)
{
        GdkPixbufModule *module;

        g_return_val_if_fail (format != NULL, FALSE);
        g_return_val_if_fail (option_key != NULL, FALSE);

        module = _gdk_pixbuf_get_named_module (format->name, NULL);
        if (!module)
                return FALSE;

        if (!_gdk_pixbuf_load_module (module, NULL))
                return FALSE;

        if (!module->is_save_option_supported)
                return FALSE;

        return (* module->is_save_option_supported) (option_key);
}

G_DEFINE_BOXED_TYPE (GdkPixbufFormat, gdk_pixbuf_format,
		     gdk_pixbuf_format_copy,
		     gdk_pixbuf_format_free)