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authorBenjamin Otte <otte@redhat.com>2021-12-20 18:40:02 +0100
committerBenjamin Otte <otte@redhat.com>2021-12-20 18:40:02 +0100
commit20dcc31d19fcb544b4d830c2c99ced6828888a86 (patch)
tree4cee4458c57318bdbbfb064775f3d2f0cb74cb56 /gsk/gskrendernodeimpl.c
parent4e6ee28bcb18c027b2857abca4ab48708a5739ad (diff)
downloadgtk+-20dcc31d19fcb544b4d830c2c99ced6828888a86.tar.gz
rendernode: Limit diff region
Limit the diff region to 30 rectangles (randomly chosen because it looked big enough to not trigger by accident and small enough to not cause performance issues). If the diff region gets more complicated, we abort to the parent node and use its bounds as the diff region instead and then continue diffing the rest of the node tree. Fixes: #4560 Fixes: #2396
Diffstat (limited to 'gsk/gskrendernodeimpl.c')
-rw-r--r--gsk/gskrendernodeimpl.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/gsk/gskrendernodeimpl.c b/gsk/gskrendernodeimpl.c
index 24bf09baac..dca0bbe585 100644
--- a/gsk/gskrendernodeimpl.c
+++ b/gsk/gskrendernodeimpl.c
@@ -33,6 +33,12 @@
#include <hb-ot.h>
+/* maximal number of rectangles we keep in a diff region before we throw
+ * the towel and just use the bounding box of the parent node.
+ * Meant to avoid performance corner cases.
+ */
+#define MAX_RECTS_IN_DIFF 30
+
static inline void
gsk_cairo_rectangle (cairo_t *cr,
const graphene_rect_t *rect)
@@ -2611,6 +2617,8 @@ static GskDiffResult
gsk_container_node_keep_func (gconstpointer elem1, gconstpointer elem2, gpointer data)
{
gsk_render_node_diff ((GskRenderNode *) elem1, (GskRenderNode *) elem2, data);
+ if (cairo_region_num_rectangles (data) > MAX_RECTS_IN_DIFF)
+ return GSK_DIFF_ABORTED;
return GSK_DIFF_OK;
}
@@ -2624,6 +2632,8 @@ gsk_container_node_change_func (gconstpointer elem, gsize idx, gpointer data)
rectangle_init_from_graphene (&rect, &node->bounds);
cairo_region_union_rectangle (region, &rect);
+ if (cairo_region_num_rectangles (region) > MAX_RECTS_IN_DIFF)
+ return GSK_DIFF_ABORTED;
return GSK_DIFF_OK;
}