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gtk/gdk-pixbuf/gdk-pixbuf-loader.c
Matthias Clasen 691a5fd50a Add sanity checks for GError handling. (#108345)
2003-04-24 18:51:07 +00:00

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/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 8 -*- */
/* GdkPixbuf library - Progressive loader object
*
* Copyright (C) 1999 The Free Software Foundation
*
* Authors: Mark Crichton <crichton@gimp.org>
* Miguel de Icaza <miguel@gnu.org>
* Federico Mena-Quintero <federico@gimp.org>
* Jonathan Blandford <jrb@redhat.com>
*
* 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, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include <string.h>
#include "gdk-pixbuf-private.h"
#include "gdk-pixbuf-animation.h"
#include "gdk-pixbuf-io.h"
#include "gdk-pixbuf-loader.h"
#include "gdk-pixbuf-marshal.h"
enum {
SIZE_PREPARED,
AREA_PREPARED,
AREA_UPDATED,
CLOSED,
LAST_SIGNAL
};
static void gdk_pixbuf_loader_class_init (GdkPixbufLoaderClass *klass);
static void gdk_pixbuf_loader_init (GdkPixbufLoader *loader);
static void gdk_pixbuf_loader_finalize (GObject *loader);
static gpointer parent_class = NULL;
static guint pixbuf_loader_signals[LAST_SIGNAL] = { 0 };
/* Internal data */
#define LOADER_HEADER_SIZE 128
typedef struct
{
GdkPixbufAnimation *animation;
gboolean closed;
guchar header_buf[LOADER_HEADER_SIZE];
gint header_buf_offset;
GdkPixbufModule *image_module;
gpointer context;
gint width;
gint height;
gboolean size_fixed;
gboolean needs_scale;
} GdkPixbufLoaderPrivate;
/**
* gdk_pixbuf_loader_get_type:
* @void:
*
* Registers the #GdkPixbufLoader class if necessary, and returns the type ID
* associated to it.
*
* Return value: The type ID of the #GdkPixbufLoader class.
**/
GType
gdk_pixbuf_loader_get_type (void)
{
static GType loader_type = 0;
if (!loader_type)
{
static const GTypeInfo loader_info = {
sizeof (GdkPixbufLoaderClass),
(GBaseInitFunc) NULL,
(GBaseFinalizeFunc) NULL,
(GClassInitFunc) gdk_pixbuf_loader_class_init,
NULL, /* class_finalize */
NULL, /* class_data */
sizeof (GdkPixbufLoader),
0, /* n_preallocs */
(GInstanceInitFunc) gdk_pixbuf_loader_init
};
loader_type = g_type_register_static (G_TYPE_OBJECT,
"GdkPixbufLoader",
&loader_info,
0);
}
return loader_type;
}
static void
gdk_pixbuf_loader_class_init (GdkPixbufLoaderClass *class)
{
GObjectClass *object_class;
object_class = (GObjectClass *) class;
parent_class = g_type_class_peek_parent (class);
object_class->finalize = gdk_pixbuf_loader_finalize;
pixbuf_loader_signals[SIZE_PREPARED] =
g_signal_new ("size_prepared",
G_TYPE_FROM_CLASS (object_class),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GdkPixbufLoaderClass, size_prepared),
NULL, NULL,
gdk_pixbuf_marshal_VOID__INT_INT,
G_TYPE_NONE, 2,
G_TYPE_INT,
G_TYPE_INT);
pixbuf_loader_signals[AREA_PREPARED] =
g_signal_new ("area_prepared",
G_TYPE_FROM_CLASS (object_class),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GdkPixbufLoaderClass, area_prepared),
NULL, NULL,
gdk_pixbuf_marshal_VOID__VOID,
G_TYPE_NONE, 0);
pixbuf_loader_signals[AREA_UPDATED] =
g_signal_new ("area_updated",
G_TYPE_FROM_CLASS (object_class),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GdkPixbufLoaderClass, area_updated),
NULL, NULL,
gdk_pixbuf_marshal_VOID__INT_INT_INT_INT,
G_TYPE_NONE, 4,
G_TYPE_INT,
G_TYPE_INT,
G_TYPE_INT,
G_TYPE_INT);
pixbuf_loader_signals[CLOSED] =
g_signal_new ("closed",
G_TYPE_FROM_CLASS (object_class),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GdkPixbufLoaderClass, closed),
NULL, NULL,
gdk_pixbuf_marshal_VOID__VOID,
G_TYPE_NONE, 0);
}
static void
gdk_pixbuf_loader_init (GdkPixbufLoader *loader)
{
GdkPixbufLoaderPrivate *priv;
priv = g_new0 (GdkPixbufLoaderPrivate, 1);
loader->priv = priv;
}
static void
gdk_pixbuf_loader_finalize (GObject *object)
{
GdkPixbufLoader *loader;
GdkPixbufLoaderPrivate *priv = NULL;
loader = GDK_PIXBUF_LOADER (object);
priv = loader->priv;
if (!priv->closed)
g_warning ("GdkPixbufLoader finalized without calling gdk_pixbuf_loader_close() - this is not allowed. You must explicitly end the data stream to the loader before dropping the last reference.");
if (priv->animation)
g_object_unref (priv->animation);
g_free (priv);
G_OBJECT_CLASS (parent_class)->finalize (object);
}
/**
* gdk_pixbuf_loader_set_size:
* @loader: A pixbuf loader.
* @width: The desired width of the image being loaded.
* @height: The desired height of the image being loaded.
*
* Causes the image to be scaled while it is loaded. The desired
* image size can be determined relative to the original size of
* the image by calling gdk_pixbuf_loader_set_size() from a
* signal handler for the ::size_prepared signal.
*
* Attempts to set the desired image size are ignored after the
* emission of the ::size_prepared signal.
*
* Since: 2.2
*/
void
gdk_pixbuf_loader_set_size (GdkPixbufLoader *loader,
gint width,
gint height)
{
GdkPixbufLoaderPrivate *priv = GDK_PIXBUF_LOADER (loader)->priv;
g_return_if_fail (width > 0 && height > 0);
if (!priv->size_fixed)
{
priv->width = width;
priv->height = height;
}
}
static void
gdk_pixbuf_loader_size_func (gint *width, gint *height, gpointer loader)
{
GdkPixbufLoaderPrivate *priv = GDK_PIXBUF_LOADER (loader)->priv;
/* allow calling gdk_pixbuf_loader_set_size() before the signal */
if (priv->width == 0 && priv->height == 0)
{
priv->width = *width;
priv->height = *height;
}
g_signal_emit (loader, pixbuf_loader_signals[SIZE_PREPARED], 0, *width, *height);
priv->size_fixed = TRUE;
*width = priv->width;
*height = priv->height;
}
static void
gdk_pixbuf_loader_prepare (GdkPixbuf *pixbuf,
GdkPixbufAnimation *anim,
gpointer loader)
{
GdkPixbufLoaderPrivate *priv = GDK_PIXBUF_LOADER (loader)->priv;
g_return_if_fail (pixbuf != NULL);
if (!priv->size_fixed)
{
/* Defend against lazy loaders which don't call size_func */
gint width = gdk_pixbuf_get_width (pixbuf);
gint height = gdk_pixbuf_get_height (pixbuf);
gdk_pixbuf_loader_size_func (&width, &height, loader);
}
priv->needs_scale = FALSE;
if (priv->width > 0 && priv->height > 0 &&
(priv->width != gdk_pixbuf_get_width (pixbuf) ||
priv->height != gdk_pixbuf_get_height (pixbuf)))
priv->needs_scale = TRUE;
if (anim)
g_object_ref (anim);
else
anim = gdk_pixbuf_non_anim_new (pixbuf);
priv->animation = anim;
if (!priv->needs_scale)
g_signal_emit (loader, pixbuf_loader_signals[AREA_PREPARED], 0);
}
static void
gdk_pixbuf_loader_update (GdkPixbuf *pixbuf,
gint x,
gint y,
gint width,
gint height,
gpointer loader)
{
GdkPixbufLoaderPrivate *priv = GDK_PIXBUF_LOADER (loader)->priv;
if (!priv->needs_scale)
g_signal_emit (loader,
pixbuf_loader_signals[AREA_UPDATED],
0,
x, y,
/* sanity check in here. Defend against an errant loader */
MIN (width, gdk_pixbuf_animation_get_width (priv->animation)),
MIN (height, gdk_pixbuf_animation_get_height (priv->animation)));
}
static gint
gdk_pixbuf_loader_load_module (GdkPixbufLoader *loader,
const char *image_type,
GError **error)
{
GdkPixbufLoaderPrivate *priv = loader->priv;
if (image_type)
{
priv->image_module = _gdk_pixbuf_get_named_module (image_type,
error);
}
else
{
priv->image_module = _gdk_pixbuf_get_module (priv->header_buf,
priv->header_buf_offset,
NULL,
error);
}
if (priv->image_module == NULL)
return 0;
if (priv->image_module->module == NULL)
if (!_gdk_pixbuf_load_module (priv->image_module, error))
return 0;
if (priv->image_module->module == NULL)
return 0;
if ((priv->image_module->begin_load == NULL) ||
(priv->image_module->stop_load == NULL) ||
(priv->image_module->load_increment == NULL))
{
g_set_error (error,
GDK_PIXBUF_ERROR,
GDK_PIXBUF_ERROR_UNSUPPORTED_OPERATION,
_("Incremental loading of image type '%s' is not supported"),
priv->image_module->module_name);
return 0;
}
priv->context = priv->image_module->begin_load (gdk_pixbuf_loader_size_func,
gdk_pixbuf_loader_prepare,
gdk_pixbuf_loader_update,
loader,
error);
if (priv->context == NULL)
{
/* Defense against broken loaders; DO NOT take this as a GError
* example
*/
if (error && *error == NULL)
{
g_warning ("Bug! loader '%s' didn't set an error on failure",
priv->image_module->module_name);
g_set_error (error,
GDK_PIXBUF_ERROR,
GDK_PIXBUF_ERROR_FAILED,
_("Internal error: Image loader module '%s'"
" failed to begin loading an image, but didn't"
" give a reason for the failure"),
priv->image_module->module_name);
}
return 0;
}
if (priv->header_buf_offset
&& priv->image_module->load_increment (priv->context, priv->header_buf, priv->header_buf_offset, error))
return priv->header_buf_offset;
return 0;
}
static int
gdk_pixbuf_loader_eat_header_write (GdkPixbufLoader *loader,
const guchar *buf,
gsize count,
GError **error)
{
gint n_bytes;
GdkPixbufLoaderPrivate *priv = loader->priv;
n_bytes = MIN(LOADER_HEADER_SIZE - priv->header_buf_offset, count);
memcpy (priv->header_buf + priv->header_buf_offset, buf, n_bytes);
priv->header_buf_offset += n_bytes;
if (priv->header_buf_offset >= LOADER_HEADER_SIZE)
{
if (gdk_pixbuf_loader_load_module (loader, NULL, error) == 0)
return 0;
}
return n_bytes;
}
/**
* gdk_pixbuf_loader_write:
* @loader: A pixbuf loader.
* @buf: Pointer to image data.
* @count: Length of the @buf buffer in bytes.
* @error: return location for errors
*
* This will cause a pixbuf loader to parse the next @count bytes of
* an image. It will return %TRUE if the data was loaded successfully,
* and %FALSE if an error occurred. In the latter case, the loader
* will be closed, and will not accept further writes. If %FALSE is
* returned, @error will be set to an error from the #GDK_PIXBUF_ERROR
* or #G_FILE_ERROR domains.
*
* Return value: %TRUE if the write was successful, or %FALSE if the loader
* cannot parse the buffer.
**/
gboolean
gdk_pixbuf_loader_write (GdkPixbufLoader *loader,
const guchar *buf,
gsize count,
GError **error)
{
GdkPixbufLoaderPrivate *priv;
g_return_val_if_fail (loader != NULL, FALSE);
g_return_val_if_fail (GDK_IS_PIXBUF_LOADER (loader), FALSE);
g_return_val_if_fail (buf != NULL, FALSE);
g_return_val_if_fail (count >= 0, FALSE);
g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
priv = loader->priv;
/* we expect it's not to be closed */
g_return_val_if_fail (priv->closed == FALSE, FALSE);
if (priv->image_module == NULL)
{
gint eaten;
eaten = gdk_pixbuf_loader_eat_header_write (loader, buf, count, error);
if (eaten <= 0)
return FALSE;
count -= eaten;
buf += eaten;
}
if (count > 0 && priv->image_module->load_increment)
{
gboolean retval;
retval = priv->image_module->load_increment (priv->context, buf, count,
error);
if (!retval && error && *error == NULL)
{
/* Fix up busted image loader */
g_warning ("Bug! loader '%s' didn't set an error on failure",
priv->image_module->module_name);
g_set_error (error,
GDK_PIXBUF_ERROR,
GDK_PIXBUF_ERROR_FAILED,
_("Internal error: Image loader module '%s'"
" failed to begin loading an image, but didn't"
" give a reason for the failure"),
priv->image_module->module_name);
}
return retval;
}
return TRUE;
}
/**
* gdk_pixbuf_loader_new:
*
* Creates a new pixbuf loader object.
*
* Return value: A newly-created pixbuf loader.
**/
GdkPixbufLoader *
gdk_pixbuf_loader_new (void)
{
return g_object_new (GDK_TYPE_PIXBUF_LOADER, NULL);
}
/**
* gdk_pixbuf_loader_new_with_type:
* @image_type: name of the image format to be loaded with the image
* @error: return location for an allocated #GError, or %NULL to ignore errors
*
* Creates a new pixbuf loader object that always attempts to parse
* image data as if it were an image of type @image_type, instead of
* identifying the type automatically. Useful if you want an error if
* the image isn't the expected type, for loading image formats
* that can't be reliably identified by looking at the data, or if
* the user manually forces a specific type.
*
* Return value: A newly-created pixbuf loader.
**/
GdkPixbufLoader *
gdk_pixbuf_loader_new_with_type (const char *image_type,
GError **error)
{
GdkPixbufLoader *retval;
GError *tmp;
g_return_val_if_fail (error == NULL || *error == NULL, NULL);
retval = g_object_new (GDK_TYPE_PIXBUF_LOADER, NULL);
tmp = NULL;
gdk_pixbuf_loader_load_module (retval, image_type, &tmp);
if (tmp != NULL)
{
g_propagate_error (error, tmp);
g_object_unref (retval);
return NULL;
}
return retval;
}
/**
* gdk_pixbuf_loader_get_pixbuf:
* @loader: A pixbuf loader.
*
* Queries the #GdkPixbuf that a pixbuf loader is currently creating.
* In general it only makes sense to call this function after the
* "area_prepared" signal has been emitted by the loader; this means
* that enough data has been read to know the size of the image that
* will be allocated. If the loader has not received enough data via
* gdk_pixbuf_loader_write(), then this function returns %NULL. The
* returned pixbuf will be the same in all future calls to the loader,
* so simply calling g_object_ref() should be sufficient to continue
* using it. Additionally, if the loader is an animation, it will
* return the "static image" of the animation
* (see gdk_pixbuf_animation_get_static_image()).
*
* Return value: The #GdkPixbuf that the loader is creating, or %NULL if not
* enough data has been read to determine how to create the image buffer.
**/
GdkPixbuf *
gdk_pixbuf_loader_get_pixbuf (GdkPixbufLoader *loader)
{
GdkPixbufLoaderPrivate *priv;
g_return_val_if_fail (loader != NULL, NULL);
g_return_val_if_fail (GDK_IS_PIXBUF_LOADER (loader), NULL);
priv = loader->priv;
if (priv->animation)
return gdk_pixbuf_animation_get_static_image (priv->animation);
else
return NULL;
}
/**
* gdk_pixbuf_loader_get_animation:
* @loader: A pixbuf loader
*
* Queries the #GdkPixbufAnimation that a pixbuf loader is currently creating.
* In general it only makes sense to call this function after the "area_prepared"
* signal has been emitted by the loader. If the loader doesn't have enough
* bytes yet (hasn't emitted the "area_prepared" signal) this function will
* return %NULL.
*
* Return value: The #GdkPixbufAnimation that the loader is loading, or %NULL if
not enough data has been read to determine the information.
**/
GdkPixbufAnimation *
gdk_pixbuf_loader_get_animation (GdkPixbufLoader *loader)
{
GdkPixbufLoaderPrivate *priv;
g_return_val_if_fail (loader != NULL, NULL);
g_return_val_if_fail (GDK_IS_PIXBUF_LOADER (loader), NULL);
priv = loader->priv;
return priv->animation;
}
/**
* gdk_pixbuf_loader_close:
* @loader: A pixbuf loader.
* @error: return location for a #GError, or %NULL to ignore errors
*
* Informs a pixbuf loader that no further writes with
* gdk_pixbuf_loader_write() will occur, so that it can free its
* internal loading structures. Also, tries to parse any data that
* hasn't yet been parsed; if the remaining data is partial or
* corrupt, an error will be returned. If %FALSE is returned, @error
* will be set to an error from the #GDK_PIXBUF_ERROR or #G_FILE_ERROR
* domains. If you're just cancelling a load rather than expecting it
* to be finished, passing %NULL for @error to ignore it is
* reasonable.
*
* Returns: %TRUE if all image data written so far was successfully
passed out via the update_area signal
**/
gboolean
gdk_pixbuf_loader_close (GdkPixbufLoader *loader,
GError **error)
{
GdkPixbufLoaderPrivate *priv;
gboolean retval = TRUE;
g_return_val_if_fail (loader != NULL, TRUE);
g_return_val_if_fail (GDK_IS_PIXBUF_LOADER (loader), TRUE);
g_return_val_if_fail (error == NULL || *error == NULL, TRUE);
priv = loader->priv;
/* we expect it's not closed */
g_return_val_if_fail (priv->closed == FALSE, TRUE);
/* We have less the 128 bytes in the image. Flush it, and keep going. */
if (priv->image_module == NULL)
{
GError *tmp = NULL;
gdk_pixbuf_loader_load_module (loader, NULL, &tmp);
if (tmp != NULL)
{
g_propagate_error (error, tmp);
retval = FALSE;
}
}
if (priv->image_module && priv->image_module->stop_load && priv->context)
{
if (!priv->image_module->stop_load (priv->context, error))
retval = FALSE;
}
priv->closed = TRUE;
if (priv->needs_scale)
{
GdkPixbuf *tmp, *pixbuf;
tmp = gdk_pixbuf_animation_get_static_image (priv->animation);
g_object_ref (tmp);
pixbuf = gdk_pixbuf_new (GDK_COLORSPACE_RGB, tmp->has_alpha, 8, priv->width, priv->height);
g_object_unref (priv->animation);
priv->animation = gdk_pixbuf_non_anim_new (pixbuf);
g_object_unref (pixbuf);
g_signal_emit (loader, pixbuf_loader_signals[AREA_PREPARED], 0);
gdk_pixbuf_scale (tmp, pixbuf, 0, 0, priv->width, priv->height, 0, 0,
(double) priv->width / tmp->width,
(double) priv->height / tmp->height,
GDK_INTERP_BILINEAR);
g_object_unref (tmp);
g_signal_emit (loader, pixbuf_loader_signals[AREA_UPDATED], 0,
0, 0, priv->width, priv->height);
}
g_signal_emit (loader, pixbuf_loader_signals[CLOSED], 0);
return retval;
}
/**
* gdk_pixbuf_loader_get_format:
* @loader: A pixbuf loader.
*
* Obtains the available information about the format of the
* currently loading image file.
*
* Returns: A #GdkPixbufFormat or %NULL. The return value is owned
* by GdkPixbuf and should not be freed.
*
* Since: 2.2
*/
GdkPixbufFormat *
gdk_pixbuf_loader_get_format (GdkPixbufLoader *loader)
{
GdkPixbufLoaderPrivate *priv;
g_return_val_if_fail (loader != NULL, NULL);
g_return_val_if_fail (GDK_IS_PIXBUF_LOADER (loader), NULL);
priv = loader->priv;
if (priv->image_module)
return _gdk_pixbuf_get_format (priv->image_module);
else
return NULL;
}
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