Changes to make gdk-pixbuf threadsafe (#157310, #157306, Colin Walters):

2004-11-12  Matthias Clasen  <mclasen@redhat.com>

	Changes to make gdk-pixbuf threadsafe  (#157310, #157306,
	Colin Walters):

	* gdk-pixbuf-io.h (enum GdkPixbufFormatFlags): Add
	GDK_PIXBUF_FORMAT_THREADSAFE to indicate that an image loader
	is threadsafe.

	* gdk-pixbuf-io.c (get_file_formats, _gdk_pixbuf_load_module):
	Use a lock to make initialization of global data structures
	threadsafe.
	* gdk-pixbuf-private.h:
	* gdk-pixbuf-io.c (_gdk_pixbuf_lock, _gdk_pixbuf_unlock):
	Auxiliary functions which use another lock to protect
	threadunsafe image loaders.

	* gdk-pixbuf-io.c (gdk_pixbuf_real_save):
	(save_to_callback_with_tmp_file):
	(gdk_pixbuf_real_save_to_callback):
	(gdk_pixbuf_new_from_xpm_data):
	(_gdk_pixbuf_generic_image_load):
	* gdk-pixbuf-animation.c (gdk_pixbuf_animation_new_from_file):
	* gdk-pixbuf-loader.c (gdk_pixbuf_loader_load_module):
	(gdk_pixbuf_loader_close):
	(gdk_pixbuf_loader_finalize):
	Use _gdk_pixbuf_lock() and _gdk_pixbuf_unlock().

	* io-ani.c, io-bmp.c, io-gif.c, io-ico.c:
	* io-jpeg.c, io-pcx.c, io-png.c, io-pnm.c:
	* io-ras.c, io-tga.c, io-wbmp.c, io-xbm.c:
	* io-xpm.c: Mark as threadsafe.

	* io-tiff.c: Remove pointless locking, mark as
	threadunsafe.

22 files changed, 211 insertions, 109 deletions

diff --git a/docs/reference/ChangeLog b/docs/reference/ChangeLog
index 4916e93e7..31be71cac 100644
--- a/docs/reference/ChangeLog
+++ b/docs/reference/ChangeLog
@@ -1,3 +1,8 @@
+2004-11-12  Matthias Clasen  <mclasen@redhat.com>
+
+	* gdk-pixbuf/tmpl/module_interface.sgml: Document 
+	GDK_PIXBUF_FORMAT_THREADSAFE.
+
 2004-11-09  Matthias Clasen  <mclasen@redhat.com>
 
 	* gtk/gtk-sections.txt: Add gtk_action_get_accel_path.
diff --git a/docs/reference/gdk-pixbuf/tmpl/module_interface.sgml b/docs/reference/gdk-pixbuf/tmpl/module_interface.sgml
index cca46f9bc..cfc176e31 100644
--- a/docs/reference/gdk-pixbuf/tmpl/module_interface.sgml
+++ b/docs/reference/gdk-pixbuf/tmpl/module_interface.sgml
@@ -193,6 +193,9 @@ operations.
 
 @GDK_PIXBUF_FORMAT_WRITABLE: the module can write out images in the format.
 @GDK_PIXBUF_FORMAT_SCALABLE: the image format is scalable
+@GDK_PIXBUF_FORMAT_THREADSAFE: the module is threadsafe. If this flag is not
+  set, &gdk-pixbuf; will use a lock to prevent multiple threads from using
+  this module at the same time. (Since 2.6)
 @Since: 2.2
 
 <!-- ##### STRUCT GdkPixbufModulePattern ##### -->
diff --git a/gdk-pixbuf/ChangeLog b/gdk-pixbuf/ChangeLog
index 44d768f5e..e4bfddb80 100644
--- a/gdk-pixbuf/ChangeLog
+++ b/gdk-pixbuf/ChangeLog
@@ -1,3 +1,39 @@
+2004-11-12  Matthias Clasen  <mclasen@redhat.com>
+
+	Changes to make gdk-pixbuf threadsafe  (#157310, #157306, 
+	Colin Walters):
+	
+	* gdk-pixbuf-io.h (enum GdkPixbufFormatFlags): Add 
+	GDK_PIXBUF_FORMAT_THREADSAFE to indicate that an image loader
+	is threadsafe.
+
+	* gdk-pixbuf-io.c (get_file_formats, _gdk_pixbuf_load_module): 
+	Use a lock to make initialization of global data structures 
+	threadsafe.
+	* gdk-pixbuf-private.h: 
+	* gdk-pixbuf-io.c (_gdk_pixbuf_lock, _gdk_pixbuf_unlock): 
+	Auxiliary functions which use another lock to protect 
+	threadunsafe image loaders.
+	
+	* gdk-pixbuf-io.c (gdk_pixbuf_real_save): 
+	(save_to_callback_with_tmp_file): 
+	(gdk_pixbuf_real_save_to_callback): 
+	(gdk_pixbuf_new_from_xpm_data): 
+	(_gdk_pixbuf_generic_image_load): 
+	* gdk-pixbuf-animation.c (gdk_pixbuf_animation_new_from_file): 
+	* gdk-pixbuf-loader.c (gdk_pixbuf_loader_load_module): 
+	(gdk_pixbuf_loader_close): 
+	(gdk_pixbuf_loader_finalize): 
+	Use _gdk_pixbuf_lock() and _gdk_pixbuf_unlock().
+
+	* io-ani.c, io-bmp.c, io-gif.c, io-ico.c:
+	* io-jpeg.c, io-pcx.c, io-png.c, io-pnm.c:
+	* io-ras.c, io-tga.c, io-wbmp.c, io-xbm.c:
+	* io-xpm.c: Mark as threadsafe.
+	
+	* io-tiff.c: Remove pointless locking, mark as 
+	threadunsafe.
+
 2004-11-10  Matthias Clasen  <mclasen@redhat.com>
 
 	* gdk-pixbuf-animation.c: 
diff --git a/gdk-pixbuf/gdk-pixbuf-animation.c b/gdk-pixbuf/gdk-pixbuf-animation.c
index 5ea1ef6ee..fa6968c15 100644
--- a/gdk-pixbuf/gdk-pixbuf-animation.c
+++ b/gdk-pixbuf/gdk-pixbuf-animation.c
@@ -181,6 +181,8 @@ gdk_pixbuf_animation_new_from_file (const char *filename,
                         return NULL;
                 }
 
+        _gdk_pixbuf_lock (image_module);
+
 	if (image_module->load_animation == NULL) {
 		GdkPixbuf *pixbuf;
 
@@ -208,7 +210,8 @@ gdk_pixbuf_animation_new_from_file (const char *filename,
                 
 		if (pixbuf == NULL) {
                         g_free (display_name);
-                        return NULL;
+                        animation = NULL;
+                        goto out_unlock;
                 }
 
                 animation = gdk_pixbuf_non_anim_new (pixbuf);
@@ -241,6 +244,8 @@ gdk_pixbuf_animation_new_from_file (const char *filename,
 
         g_free (display_name);
 
+ out_unlock:
+        _gdk_pixbuf_unlock (image_module);
 	return animation;
 }
 
diff --git a/gdk-pixbuf/gdk-pixbuf-io.c b/gdk-pixbuf/gdk-pixbuf-io.c
index 7e12ee6e1..9ad408748 100644
--- a/gdk-pixbuf/gdk-pixbuf-io.c
+++ b/gdk-pixbuf/gdk-pixbuf-io.c
@@ -76,6 +76,25 @@ format_check (GdkPixbufModule *module, guchar *buffer, int size)
 	return 0;
 }
 
+G_LOCK_DEFINE_STATIC (init_lock);
+G_LOCK_DEFINE_STATIC (threadunsafe_loader_lock);
+
+void
+_gdk_pixbuf_lock (GdkPixbufModule *image_module)
+{
+ 	if (!(image_module->info->flags & GDK_PIXBUF_FORMAT_THREADSAFE)) {
+ 		G_LOCK (threadunsafe_loader_lock);
+ 	}
+}
+ 
+void
+_gdk_pixbuf_unlock (GdkPixbufModule *image_module)
+{
+	if (!(image_module->info->flags & GDK_PIXBUF_FORMAT_THREADSAFE)) {
+		G_UNLOCK (threadunsafe_loader_lock);
+	}
+}
+
 static GSList *file_formats = NULL;
 
 static void gdk_pixbuf_io_init ();
@@ -83,8 +102,10 @@ static void gdk_pixbuf_io_init ();
 static GSList *
 get_file_formats (void)
 {
+	G_LOCK (init_lock);
 	if (file_formats == NULL)
 		gdk_pixbuf_io_init ();
+	G_UNLOCK (init_lock);
 	
 	return file_formats;
 }
@@ -396,9 +417,9 @@ gdk_pixbuf_io_init (void)
 /* 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           */
-gboolean
-_gdk_pixbuf_load_module (GdkPixbufModule *image_module,
-                         GError         **error)
+static gboolean
+_gdk_pixbuf_load_module_unlocked (GdkPixbufModule *image_module,
+				  GError         **error)
 {
 	char *path;
 	GModule *module;
@@ -433,6 +454,19 @@ _gdk_pixbuf_load_module (GdkPixbufModule *image_module,
                 return FALSE;
         }
 }
+
+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;
+}
 #else
 
 #define module(type) \
@@ -593,11 +627,11 @@ gdk_pixbuf_io_init ()
 	};
 	gchar **name;
 	GdkPixbufModule *module = NULL;
-	
+
 	for (name = included_formats; *name; name++) {
 		module = g_new0 (GdkPixbufModule, 1);
 		module->module_name = *name;
-		if (_gdk_pixbuf_load_module (module, NULL))
+		if (_gdk_pixbuf_load_module_unlocked (module, NULL))
 			file_formats = g_slist_prepend (file_formats, module);
 		else
 			g_free (module);
@@ -703,37 +737,37 @@ _gdk_pixbuf_generic_image_load (GdkPixbufModule *module,
 	GdkPixbufAnimation *animation = NULL;
 	gpointer context;
 
-	if (module->load != NULL)
-		return (* module->load) (f, error);
-	
-	if (module->begin_load != NULL) {
+	_gdk_pixbuf_lock (module);
+
+	if (module->load != NULL) {
+		pixbuf = (* module->load) (f, error);
+	} else if (module->begin_load != NULL) {
 		
 		context = module->begin_load (NULL, prepared_notify, NULL, &pixbuf, error);
 	
 		if (!context)
-			return NULL;
+			goto out;
 		
 		while (!feof (f) && !ferror (f)) {
 			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)
+					if (pixbuf != NULL) {
 						g_object_unref (pixbuf);
-					return NULL;
+						pixbuf = NULL;
+					}
+					goto out;
 				}
 		}
 		
 		if (!module->stop_load (context, error)) {
-			if (pixbuf != NULL)
+			if (pixbuf != NULL) {
 				g_object_unref (pixbuf);
-			return NULL;
+				pixbuf = NULL;
+			}
 		}
-		
-		return pixbuf;
-	}
-	
-	if (module->load_animation != NULL) {
+	} else if (module->load_animation != NULL) {
 		animation = (* module->load_animation) (f, error);
 		if (animation != NULL) {
 			pixbuf = gdk_pixbuf_animation_get_static_image (animation);
@@ -741,12 +775,12 @@ _gdk_pixbuf_generic_image_load (GdkPixbufModule *module,
 			g_object_ref (pixbuf);
 
 			g_object_unref (animation);
-			
-			return pixbuf;
 		}
 	}
 
-	return NULL;
+ out:
+	_gdk_pixbuf_unlock (module);
+	return pixbuf;
 }
 
 /**
@@ -1134,14 +1168,18 @@ gdk_pixbuf_new_from_xpm_data (const char **data)
                         return NULL;
                 }
         }
-          
+
+	_gdk_pixbuf_lock (xpm_module);
+
 	if (xpm_module->load_xpm_data == NULL) {
 		g_warning ("gdk-pixbuf XPM module lacks XPM data capability");
-		return NULL;
-	} else
+		pixbuf = NULL;
+	} else {
 		load_xpm_data = xpm_module->load_xpm_data;
+		pixbuf = (* load_xpm_data) (data);
+	}
 
-	pixbuf = (* load_xpm_data) (data);
+	_gdk_pixbuf_unlock (xpm_module);
 	return pixbuf;
 }
 
@@ -1210,39 +1248,43 @@ gdk_pixbuf_real_save (GdkPixbuf     *pixbuf,
                       gchar        **values,
                       GError       **error)
 {
-       GdkPixbufModule *image_module = NULL;       
+	gboolean ret;
+	GdkPixbufModule *image_module = NULL;       
 
-       image_module = _gdk_pixbuf_get_named_module (type, error);
+	image_module = _gdk_pixbuf_get_named_module (type, error);
 
-       if (image_module == NULL)
-               return FALSE;
+	if (image_module == NULL)
+		return FALSE;
        
-       if (image_module->module == NULL)
-               if (!_gdk_pixbuf_load_module (image_module, error))
-                       return FALSE;
+	if (image_module->module == NULL)
+		if (!_gdk_pixbuf_load_module (image_module, error))
+			return FALSE;
 
-       if (image_module->save) {
-	       /* save normally */
-	       return (* image_module->save) (filehandle, pixbuf,
+	_gdk_pixbuf_lock (image_module);
+
+	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 */
-	       return (* image_module->save_to_callback) (save_to_file_callback,
+	} 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);
-               return FALSE;
-       }
+	} 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;
+	}
+
+	_gdk_pixbuf_unlock (image_module);
+	return ret;
 }
 
 #define TMP_FILE_BUF_SIZE 4096
@@ -1283,8 +1325,13 @@ save_to_callback_with_tmp_file (GdkPixbufModule   *image_module,
 			     _("Failed to open temporary file"));
 		goto end;
 	}
-	if (!(* image_module->save) (f, pixbuf, keys, values, error))
+
+	_gdk_pixbuf_lock (image_module);
+	retval = (image_module->save) (f, pixbuf, keys, values, error);
+	_gdk_pixbuf_unlock (image_module);
+	if (!retval)
 		goto end;
+
 	rewind (f);
 	for (;;) {
 		n = fread (buf, 1, TMP_FILE_BUF_SIZE, f);
@@ -1326,39 +1373,43 @@ gdk_pixbuf_real_save_to_callback (GdkPixbuf         *pixbuf,
 				  gchar            **values,
 				  GError           **error)
 {
-       GdkPixbufModule *image_module = NULL;       
+	gboolean ret;
+	GdkPixbufModule *image_module = NULL;       
 
-       image_module = _gdk_pixbuf_get_named_module (type, error);
+	image_module = _gdk_pixbuf_get_named_module (type, error);
 
-       if (image_module == NULL)
-               return FALSE;
+	if (image_module == NULL)
+		return FALSE;
        
-       if (image_module->module == NULL)
-               if (!_gdk_pixbuf_load_module (image_module, error))
-                       return FALSE;
+	if (image_module->module == NULL)
+		if (!_gdk_pixbuf_load_module (image_module, error))
+			return FALSE;
+
+	_gdk_pixbuf_lock (image_module);
 
-       if (image_module->save_to_callback) {
-	       /* save normally */
-	       return (* image_module->save_to_callback) (save_func, user_data, 
+	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 */
-	       return save_to_callback_with_tmp_file (image_module, pixbuf,
+	} 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);
-               return FALSE;
-       }
+	} 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;
+	}
+
+	_gdk_pixbuf_unlock (image_module);
+	return ret;
 }
 
  
diff --git a/gdk-pixbuf/gdk-pixbuf-io.h b/gdk-pixbuf/gdk-pixbuf-io.h
index 3eafd5f82..e64bee7e0 100644
--- a/gdk-pixbuf/gdk-pixbuf-io.h
+++ b/gdk-pixbuf/gdk-pixbuf-io.h
@@ -144,7 +144,8 @@ gboolean gdk_pixbuf_set_option  (GdkPixbuf   *pixbuf,
 typedef enum /*< skip >*/
 {
   GDK_PIXBUF_FORMAT_WRITABLE = 1 << 0,
-  GDK_PIXBUF_FORMAT_SCALABLE = 1 << 1
+  GDK_PIXBUF_FORMAT_SCALABLE = 1 << 1,
+  GDK_PIXBUF_FORMAT_THREADSAFE = 1 << 2
 } GdkPixbufFormatFlags;
 
 struct _GdkPixbufFormat {
diff --git a/gdk-pixbuf/gdk-pixbuf-loader.c b/gdk-pixbuf/gdk-pixbuf-loader.c
index b5c53d603..0ce63605d 100644
--- a/gdk-pixbuf/gdk-pixbuf-loader.c
+++ b/gdk-pixbuf/gdk-pixbuf-loader.c
@@ -50,7 +50,6 @@ 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
@@ -59,6 +58,7 @@ typedef struct
 {
         GdkPixbufAnimation *animation;
         gboolean closed;
+        gboolean holds_threadlock;
         guchar header_buf[LOADER_HEADER_SIZE];
         gint header_buf_offset;
         GdkPixbufModule *image_module;
@@ -225,8 +225,12 @@ gdk_pixbuf_loader_finalize (GObject *object)
         loader = GDK_PIXBUF_LOADER (object);
         priv = loader->priv;
 
-        if (!priv->closed)
+        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->holds_threadlock) {
+                        _gdk_pixbuf_unlock (priv->image_module);
+                }
+        }
         if (priv->animation)
                 g_object_unref (priv->animation);
   
@@ -382,6 +386,11 @@ gdk_pixbuf_loader_load_module (GdkPixbufLoader *loader,
                         return 0;
                 }
 
+	if (!priv->holds_threadlock) {
+                _gdk_pixbuf_lock (priv->image_module);
+                priv->holds_threadlock = TRUE;
+        }
+
         priv->context = priv->image_module->begin_load (gdk_pixbuf_loader_size_func,
                                                         gdk_pixbuf_loader_prepare,
                                                         gdk_pixbuf_loader_update,
@@ -736,6 +745,11 @@ gdk_pixbuf_loader_close (GdkPixbufLoader *loader,
                 }
   
         priv->closed = TRUE;
+	if (priv->image_module) {
+                g_assert (priv->holds_threadlock);
+                _gdk_pixbuf_unlock (priv->image_module);
+                priv->holds_threadlock = FALSE;
+        }
 
         if (priv->needs_scale) 
                 {
diff --git a/gdk-pixbuf/gdk-pixbuf-private.h b/gdk-pixbuf/gdk-pixbuf-private.h
index e81478f99..59053a99d 100644
--- a/gdk-pixbuf/gdk-pixbuf-private.h
+++ b/gdk-pixbuf/gdk-pixbuf-private.h
@@ -79,6 +79,9 @@ struct _GdkPixbufClass {
 
 #ifdef GDK_PIXBUF_ENABLE_BACKEND
 
+void _gdk_pixbuf_lock (GdkPixbufModule *image_module);
+void _gdk_pixbuf_unlock (GdkPixbufModule *image_module);
+
 GdkPixbufModule *_gdk_pixbuf_get_module (guchar *buffer, guint size,
                                          const gchar *filename,
                                          GError **error);
diff --git a/gdk-pixbuf/io-ani.c b/gdk-pixbuf/io-ani.c
index 5e7b6beb9..5568ad65d 100644
--- a/gdk-pixbuf/io-ani.c
+++ b/gdk-pixbuf/io-ani.c
@@ -676,7 +676,7 @@ MODULE_ENTRY (ani, fill_info) (GdkPixbufFormat *info)
 	info->description = N_("The ANI image format");
 	info->mime_types = mime_types;
 	info->extensions = extensions;
-	info->flags = 0;
+	info->flags = GDK_PIXBUF_FORMAT_THREADSAFE;
 	info->license = "LGPL";
 }
 
diff --git a/gdk-pixbuf/io-bmp.c b/gdk-pixbuf/io-bmp.c
index 015eca8da..14b7caa93 100644
--- a/gdk-pixbuf/io-bmp.c
+++ b/gdk-pixbuf/io-bmp.c
@@ -1132,7 +1132,7 @@ MODULE_ENTRY (bmp, fill_info) (GdkPixbufFormat *info)
 	info->description = N_("The BMP image format");
 	info->mime_types = mime_types;
 	info->extensions = extensions;
-	info->flags = 0;
+	info->flags = GDK_PIXBUF_FORMAT_THREADSAFE;
 	info->license = "LGPL";
 }
 
diff --git a/gdk-pixbuf/io-gif.c b/gdk-pixbuf/io-gif.c
index 1320922e7..fd78e586a 100644
--- a/gdk-pixbuf/io-gif.c
+++ b/gdk-pixbuf/io-gif.c
@@ -1643,6 +1643,6 @@ MODULE_ENTRY (gif, fill_info) (GdkPixbufFormat *info)
 	info->description = N_("The GIF image format");
 	info->mime_types = mime_types;
 	info->extensions = extensions;
-	info->flags = 0;
+	info->flags = GDK_PIXBUF_FORMAT_THREADSAFE;
 	info->license = "LGPL";
 }
diff --git a/gdk-pixbuf/io-ico.c b/gdk-pixbuf/io-ico.c
index 86612dd71..022c93a3c 100644
--- a/gdk-pixbuf/io-ico.c
+++ b/gdk-pixbuf/io-ico.c
@@ -1210,7 +1210,7 @@ MODULE_ENTRY (ico, fill_info) (GdkPixbufFormat *info)
 	info->description = N_("The ICO image format");
 	info->mime_types = mime_types;
 	info->extensions = extensions;
-	info->flags = GDK_PIXBUF_FORMAT_WRITABLE;
+	info->flags = GDK_PIXBUF_FORMAT_WRITABLE | GDK_PIXBUF_FORMAT_THREADSAFE;
 	info->license = "LGPL";
 }
 
diff --git a/gdk-pixbuf/io-jpeg.c b/gdk-pixbuf/io-jpeg.c
index 1bf4bede1..7f2159476 100644
--- a/gdk-pixbuf/io-jpeg.c
+++ b/gdk-pixbuf/io-jpeg.c
@@ -1071,6 +1071,6 @@ MODULE_ENTRY (jpeg, fill_info) (GdkPixbufFormat *info)
 	info->description = N_("The JPEG image format");
 	info->mime_types = mime_types;
 	info->extensions = extensions;
-	info->flags = GDK_PIXBUF_FORMAT_WRITABLE;
+	info->flags = GDK_PIXBUF_FORMAT_WRITABLE | GDK_PIXBUF_FORMAT_THREADSAFE;
 	info->license = "LGPL";
 }
diff --git a/gdk-pixbuf/io-pcx.c b/gdk-pixbuf/io-pcx.c
index 0b1f9b159..d1042cb7d 100644
--- a/gdk-pixbuf/io-pcx.c
+++ b/gdk-pixbuf/io-pcx.c
@@ -758,6 +758,6 @@ MODULE_ENTRY (pcx, fill_info) (GdkPixbufFormat *info)
 	info->description = N_("The PCX image format");
 	info->mime_types = mime_types;
 	info->extensions = extensions;
-	info->flags = 0;
+	info->flags = GDK_PIXBUF_FORMAT_THREADSAFE;
 	info->license = "LGPL";
 }
diff --git a/gdk-pixbuf/io-png.c b/gdk-pixbuf/io-png.c
index 3d4501fa2..7e9fb36de 100644
--- a/gdk-pixbuf/io-png.c
+++ b/gdk-pixbuf/io-png.c
@@ -994,6 +994,6 @@ MODULE_ENTRY (png, fill_info) (GdkPixbufFormat *info)
 	info->description = N_("The PNG image format");
 	info->mime_types = mime_types;
 	info->extensions = extensions;
-	info->flags = GDK_PIXBUF_FORMAT_WRITABLE;
+	info->flags = GDK_PIXBUF_FORMAT_WRITABLE | GDK_PIXBUF_FORMAT_THREADSAFE;
 	info->license = "LGPL";
 }
diff --git a/gdk-pixbuf/io-pnm.c b/gdk-pixbuf/io-pnm.c
index 7d9401450..4d2fb1ff3 100644
--- a/gdk-pixbuf/io-pnm.c
+++ b/gdk-pixbuf/io-pnm.c
@@ -1082,6 +1082,6 @@ MODULE_ENTRY (pnm, fill_info) (GdkPixbufFormat *info)
 	info->description = N_("The PNM/PBM/PGM/PPM image format family");
 	info->mime_types = mime_types;
 	info->extensions = extensions;
-	info->flags = 0;
+	info->flags = GDK_PIXBUF_FORMAT_THREADSAFE;
 	info->license = "LGPL";
 }
diff --git a/gdk-pixbuf/io-ras.c b/gdk-pixbuf/io-ras.c
index 9fe936161..6c20654c2 100644
--- a/gdk-pixbuf/io-ras.c
+++ b/gdk-pixbuf/io-ras.c
@@ -543,7 +543,7 @@ MODULE_ENTRY (ras, fill_info) (GdkPixbufFormat *info)
 	info->description = N_("The Sun raster image format");
 	info->mime_types = mime_types;
 	info->extensions = extensions;
-	info->flags = 0;
+	info->flags = GDK_PIXBUF_FORMAT_THREADSAFE;
 	info->license = "LGPL";
 }
 
diff --git a/gdk-pixbuf/io-tga.c b/gdk-pixbuf/io-tga.c
index f4102bdf2..2dc753822 100644
--- a/gdk-pixbuf/io-tga.c
+++ b/gdk-pixbuf/io-tga.c
@@ -995,6 +995,6 @@ MODULE_ENTRY (tga, fill_info) (GdkPixbufFormat *info)
 	info->description = N_("The Targa image format");
 	info->mime_types = mime_types;
 	info->extensions = extensions;
-	info->flags = 0;
+	info->flags = GDK_PIXBUF_FORMAT_THREADSAFE;
 	info->license = "LGPL";
 }
diff --git a/gdk-pixbuf/io-tiff.c b/gdk-pixbuf/io-tiff.c
index 9beb045b0..c58d9cb49 100644
--- a/gdk-pixbuf/io-tiff.c
+++ b/gdk-pixbuf/io-tiff.c
@@ -62,10 +62,6 @@ struct _TiffContext
 
 
 
-/* There's no user data for the error handlers, so we just have to
- * put a big-ass lock on the whole TIFF loader
- */
-G_LOCK_DEFINE_STATIC (tiff_loader);
 static char *global_error = NULL;
 static TIFFErrorHandler orig_error_handler = NULL;
 static TIFFErrorHandler orig_warning_handler = NULL;
@@ -242,10 +238,8 @@ tiff_image_parse (TIFF *tiff, TiffContext *context, GError **error)
                 return NULL;
         }
 
-        G_UNLOCK (tiff_loader);
 	if (context)
 		(* context->prepare_func) (pixbuf, NULL, context->user_data);
-        G_LOCK (tiff_loader);
 
 #if TIFFLIB_VERSION >= 20031226
         if (tifflibversion(&major, &minor, &revision) && major == 3 &&
@@ -330,10 +324,8 @@ tiff_image_parse (TIFF *tiff, TiffContext *context, GError **error)
                 _TIFFfree (rast);
              }
 
-        G_UNLOCK (tiff_loader);
 	if (context)
 		(* context->update_func) (pixbuf, 0, 0, width, height, context->user_data);
-        G_LOCK (tiff_loader);
         
         return pixbuf;
 }
@@ -351,8 +343,6 @@ gdk_pixbuf__tiff_image_load (FILE *f, GError **error)
         
         g_return_val_if_fail (f != NULL, NULL);
 
-        G_LOCK (tiff_loader);
-
         tiff_push_handlers ();
         
         fd = fileno (f);
@@ -371,7 +361,6 @@ gdk_pixbuf__tiff_image_load (FILE *f, GError **error)
                                 _("Failed to open TIFF image"));
                 tiff_pop_handlers ();
 
-                G_UNLOCK (tiff_loader);
                 return NULL;
         }
 
@@ -386,8 +375,6 @@ gdk_pixbuf__tiff_image_load (FILE *f, GError **error)
         
         tiff_pop_handlers ();
 
-        G_UNLOCK (tiff_loader);
-        
         return pixbuf;
 }
 
@@ -504,8 +491,6 @@ gdk_pixbuf__tiff_image_stop_load (gpointer data,
         
         g_return_val_if_fail (data != NULL, FALSE);
 
-        G_LOCK (tiff_loader);
-        
         tiff_push_handlers ();
         
         tiff = TIFFClientOpen ("libtiff-pixbuf", "r", data, 
@@ -546,8 +531,6 @@ gdk_pixbuf__tiff_image_stop_load (gpointer data,
 
         tiff_pop_handlers ();
 
-        G_UNLOCK (tiff_loader);
-
         return retval;
 }
 
@@ -627,6 +610,7 @@ MODULE_ENTRY (tiff, fill_info) (GdkPixbufFormat *info)
 	info->description = N_("The TIFF image format");
 	info->mime_types = mime_types;
 	info->extensions = extensions;
+        /* not threadsafe, due the the error handler handling */
 	info->flags = 0;
 	info->license = "LGPL";
 }
diff --git a/gdk-pixbuf/io-wbmp.c b/gdk-pixbuf/io-wbmp.c
index 098c8c805..24779b97e 100644
--- a/gdk-pixbuf/io-wbmp.c
+++ b/gdk-pixbuf/io-wbmp.c
@@ -368,6 +368,6 @@ MODULE_ENTRY (wbmp, fill_info) (GdkPixbufFormat *info)
 	info->description = N_("The WBMP image format");
 	info->mime_types = mime_types;
 	info->extensions = extensions;
-	info->flags = 0;
+	info->flags = GDK_PIXBUF_FORMAT_THREADSAFE;
 	info->license = "LGPL";
 }
diff --git a/gdk-pixbuf/io-xbm.c b/gdk-pixbuf/io-xbm.c
index 45d4be79e..6c9244cf6 100644
--- a/gdk-pixbuf/io-xbm.c
+++ b/gdk-pixbuf/io-xbm.c
@@ -476,6 +476,6 @@ MODULE_ENTRY (xbm, fill_info) (GdkPixbufFormat *info)
 	info->description = N_("The XBM image format");
 	info->mime_types = mime_types;
 	info->extensions = extensions;
-	info->flags = 0;
+	info->flags = GDK_PIXBUF_FORMAT_THREADSAFE;
 	info->license = "LGPL";
 }
diff --git a/gdk-pixbuf/io-xpm.c b/gdk-pixbuf/io-xpm.c
index 67b1b011e..f8267d5b7 100644
--- a/gdk-pixbuf/io-xpm.c
+++ b/gdk-pixbuf/io-xpm.c
@@ -1559,6 +1559,6 @@ MODULE_ENTRY (xpm, fill_info) (GdkPixbufFormat *info)
 	info->description = N_("The XPM image format");
 	info->mime_types = mime_types;
 	info->extensions = extensions;
-	info->flags = 0;
+	info->flags = GDK_PIXBUF_FORMAT_THREADSAFE;
 	info->license = "LGPL";
 }