Bug 813124 - Make Cairo's image surface correctly handle having multiple clip paths set on the context. r=jrmuizel,roc

gfx/cairo/README

@@ -196,6 +196,8 @@ setlcdfilter_in_tree.patch: bug 790139; force cairo to use FT_Library_SetLcdFilt
 
 dwrite-font-match-robustness.patch: bug 717178, don't crash when _name_tables_match is passed a nil scaled-font
 
+handle-multi-path-clip.patch: bug 813124, handle multiple clip paths correctly
+
 ==== pixman patches ====
 
 pixman-android-cpu-detect.patch: Add CPU detection support for Android, where we can't reliably access /proc/self/auxv.

gfx/cairo/cairo/src/cairo-image-surface.c

@@ -2890,6 +2890,8 @@ _composite_boxes (cairo_image_surface_t *dst,
 
     if (clip != NULL) {
 	status = _cairo_clip_get_region (clip, &clip_region);
+	if (unlikely (status == CAIRO_INT_STATUS_NOTHING_TO_DO))
+	    return CAIRO_STATUS_SUCCESS;
 	need_clip_mask = status == CAIRO_INT_STATUS_UNSUPPORTED;
 	if (need_clip_mask &&
 	    (op == CAIRO_OPERATOR_SOURCE || ! extents->is_bounded))
@@ -3205,20 +3207,10 @@ _clip_and_composite_trapezoids (cairo_image_surface_t *dst,
 static cairo_clip_path_t *
 _clip_get_single_path (cairo_clip_t *clip)
 {
-    cairo_clip_path_t *iter = clip->path;
-    cairo_clip_path_t *path = NULL;
+    if (clip->path->prev == NULL)
+      return clip->path;
 
-    do {
-	if ((iter->flags & CAIRO_CLIP_PATH_IS_BOX) == 0) {
-	    if (path != NULL)
-		return FALSE;
-
-	    path = iter;
-	}
-	iter = iter->prev;
-    } while (iter != NULL);
-
-    return path;
+    return NULL;
 }
 
 /* high level image interface */

gfx/cairo/handle-multi-path-clip.patch

@@ -0,0 +1,57 @@
+diff --git a/gfx/cairo/cairo/src/cairo-image-surface.c b/gfx/cairo/cairo/src/cairo-image-surface.c
+--- a/gfx/cairo/cairo/src/cairo-image-surface.c
++++ b/gfx/cairo/cairo/src/cairo-image-surface.c
+@@ -2885,16 +2885,18 @@ static cairo_status_t
+     cairo_bool_t need_clip_mask = FALSE;
+     cairo_status_t status;
+     struct _cairo_boxes_chunk *chunk;
+     uint32_t pixel;
+     int i;
+ 
+     if (clip != NULL) {
+ 	status = _cairo_clip_get_region (clip, &clip_region);
++	if (unlikely (status == CAIRO_INT_STATUS_NOTHING_TO_DO))
++	    return CAIRO_STATUS_SUCCESS;
+ 	need_clip_mask = status == CAIRO_INT_STATUS_UNSUPPORTED;
+ 	if (need_clip_mask &&
+ 	    (op == CAIRO_OPERATOR_SOURCE || ! extents->is_bounded))
+ 	{
+ 	    return CAIRO_INT_STATUS_UNSUPPORTED;
+ 	}
+ 
+ 	if (clip_region != NULL && cairo_region_num_rectangles (clip_region) == 1)
+@@ -3200,30 +3202,20 @@ static cairo_status_t
+     return _clip_and_composite (dst, op, src,
+ 				_composite_traps, &info,
+ 				extents, clip);
+ }
+ 
+ static cairo_clip_path_t *
+ _clip_get_single_path (cairo_clip_t *clip)
+ {
+-    cairo_clip_path_t *iter = clip->path;
+-    cairo_clip_path_t *path = NULL;
+-
+-    do {
+-	if ((iter->flags & CAIRO_CLIP_PATH_IS_BOX) == 0) {
+-	    if (path != NULL)
+-		return FALSE;
+-
+-	    path = iter;
+-	}
+-	iter = iter->prev;
+-    } while (iter != NULL);
+-
+-    return path;
++    if (clip->path->prev == NULL)
++      return clip->path;
++
++    return NULL;
+ }
+ 
+ /* high level image interface */
+ 
+ static cairo_int_status_t
+ _cairo_image_surface_paint (void			*abstract_surface,
+ 			    cairo_operator_t		 op,
+ 			    const cairo_pattern_t	*source,