commit 796bc1db0ef1600ed8d2e7206642306982210055
author Jim Van Verth <jvanverth@google.com> Tue Jun 19 15:00:28 2018 -0400
committer Kevin Lubick <kjlubick@google.com> Tue Jun 19 19:36:49 2018 +0000
tree 1c9b8052d209e5212d27bd1cae03e4eeb8f1bed8
parent 99ca453634e66c570c8b28fa188bb427edda848b

Limit iterations when computing convex inset.

In the worst case we should compare each vertex in the polygon
to the others just once, so we should have at worst n^2 iterations.

Bug: skia:8079
Change-Id: Ic22064e86d6eb08d9165b2feb5050701ec8e9639
Reviewed-on: https://skia-review.googlesource.com/135865
Auto-Submit: Jim Van Verth <jvanverth@google.com>
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Kevin Lubick <kjlubick@google.com>

src/utils/SkOffsetPolygon.cpp

diff --git a/src/utils/SkOffsetPolygon.cpp b/src/utils/SkOffsetPolygon.cpp
index b335a25..81b692f 100755
--- a/src/utils/SkOffsetPolygon.cpp
+++ b/src/utils/SkOffsetPolygon.cpp
@@ -308,7 +308,13 @@
     int prevIndex = inputPolygonSize - 1;
     int currIndex = 0;
     int insetVertexCount = inputPolygonSize;
+    int iterations = 0;
     while (prevIndex != currIndex) {
+        ++iterations;
+        if (iterations > inputPolygonSize*inputPolygonSize) {
+            return false;
+        }
+
         if (!edgeData[prevIndex].fValid) {
             prevIndex = (prevIndex + inputPolygonSize - 1) % inputPolygonSize;
             continue;