[surface] Pass a separate closure for the mime-type destroy notifier.

A limitation of the current API was that the destroy notifier was called
on the mime-data block. This prevents the user from passing in a pointer
to a managed block, for example a mime-data block belonging to a
ref-counted object. We can overcome this by allowing the user to specify
the closure to be used with the destroy notifier.

src/cairo-png.c

@@ -662,7 +662,8 @@ read_png (struct png_read_closure_t *png_closure)
 					  CAIRO_MIME_TYPE_PNG,
 					  mime_data,
 					  mime_data_length,
-					  free);
+					  free,
+					  mime_data);
     if (status) {
 	free (mime_data);
 	cairo_surface_destroy (surface);

src/cairo-surface.c

@@ -640,8 +640,8 @@ _cairo_mime_data_destroy (void *ptr)
     if (! _cairo_reference_count_dec_and_test (&mime_data->ref_count))
 	return;
 
-    if (mime_data->destroy && mime_data->data)
-	mime_data->destroy (mime_data->data);
+    if (mime_data->destroy && mime_data->closure)
+	mime_data->destroy (mime_data->closure);
 
     free (mime_data);
 }
@@ -655,6 +655,7 @@ _cairo_mime_data_destroy (void *ptr)
  * @destroy: a #cairo_destroy_func_t which will be called when the
  * surface is destroyed or when new image data is attached using the
  * same mime type.
+ * @closure: the data to be passed to the @destroy notifier
  *
  * Attach an image in the format @mime_type to @surface. To remove
  * the data from a surface, call this function with same mime type
@@ -670,7 +671,8 @@ cairo_surface_set_mime_data (cairo_surface_t		*surface,
                              const char			*mime_type,
                              const unsigned char	*data,
                              unsigned int		 length,
-			     cairo_destroy_func_t	 destroy)
+			     cairo_destroy_func_t	 destroy,
+			     void			*closure)
 {
     cairo_status_t status;
     cairo_mime_data_t *mime_data;
@@ -692,6 +694,7 @@ cairo_surface_set_mime_data (cairo_surface_t		*surface,
 	mime_data->data = (unsigned char *) data;
 	mime_data->length = length;
 	mime_data->destroy = destroy;
+	mime_data->closure = closure;
     } else
 	mime_data = NULL;
 

src/cairo-types-private.h

@@ -349,6 +349,7 @@ struct _cairo_mime_data {
     unsigned char *data;
     unsigned int length;
     cairo_destroy_func_t destroy;
+    void *closure;
 };
 
 #endif /* CAIRO_TYPES_PRIVATE_H */

src/cairo.h

@@ -1957,11 +1957,12 @@ cairo_surface_get_mime_data (cairo_surface_t		*surface,
                              unsigned int		*length);
 
 cairo_public cairo_status_t
-cairo_surface_set_mime_data (cairo_surface_t		 *surface,
-                             const char			 *mime_type,
-                             const unsigned char         *data,
-                             unsigned int                 length,
-			     cairo_destroy_func_t	  destroy);
+cairo_surface_set_mime_data (cairo_surface_t		*surface,
+                             const char			*mime_type,
+                             const unsigned char	*data,
+                             unsigned int		 length,
+			     cairo_destroy_func_t	 destroy,
+			     void			*closure);
 
 cairo_public void
 cairo_surface_get_font_options (cairo_surface_t      *surface,

test/mime-data.c

@@ -96,7 +96,8 @@ paint_file (cairo_t *cr,
     image = cairo_image_surface_create (CAIRO_FORMAT_RGB24, 200, 50);
 
     status = cairo_surface_set_mime_data (image, mime_type,
-					  mime_data, mime_length, free);
+					  mime_data, mime_length,
+					  free, mime_data);
     if (status) {
 	cairo_surface_destroy (image);
 	return cairo_test_status_from_status (ctx, status);

test/pdf-mime-data.c

@@ -106,7 +106,9 @@ preamble (cairo_test_context_t *ctx)
 	return test_status;
     }
 
-    cairo_surface_set_mime_data (image, CAIRO_MIME_TYPE_JPEG, data, len, free);
+    cairo_surface_set_mime_data (image, CAIRO_MIME_TYPE_JPEG,
+				 data, len,
+				 free, data);
     width = cairo_image_surface_get_width (image);
     height = cairo_image_surface_get_height (image);
 

util/cairo-trace/trace.c

@@ -2771,7 +2771,8 @@ cairo_surface_set_mime_data (cairo_surface_t		*surface,
                              const char			*mime_type,
                              const unsigned char	*data,
                              unsigned int		 length,
-			     cairo_destroy_func_t	 destroy)
+			     cairo_destroy_func_t	 destroy,
+			     void			*closure)
 {
     if (surface != NULL && _write_lock ()) {
 	_emit_surface (surface);
@@ -2787,7 +2788,8 @@ cairo_surface_set_mime_data (cairo_surface_t		*surface,
 		   surface,
 		   mime_type,
 		   data, length,
-		   destroy);
+		   destroy,
+		   closure);
 }
 
 cairo_status_t