Bug 1206915 - Handle nested PaintFrame() calls correctly during paint dumping. r=mattwoodrow,BenWa

--HG--
extra : source : fab68f61b2f73bbd9b1e9a0c8f542ced62da60b0

layout/base/nsLayoutUtils.cpp

@@ -8,6 +8,7 @@
 
 #include "mozilla/ArrayUtils.h"
 #include "mozilla/BasicEvents.h"
+#include "mozilla/ClearOnShutdown.h"
 #include "mozilla/EventDispatcher.h"
 #include "mozilla/FloatingPoint.h"
 #include "mozilla/gfx/PathHelpers.h"
@@ -2881,7 +2882,20 @@ nsLayoutUtils::CombineBreakType(uint8_t aOrigBreakType,
 #include <stdio.h>
 
 static bool gDumpEventList = false;
-int gPaintCount = 0;
+
+// nsLayoutUtils::PaintFrame() can call itself recursively, so rather than
+// maintaining a single paint count, we need a stack.
+StaticAutoPtr<nsTArray<int>> gPaintCountStack;
+
+struct AutoNestedPaintCount {
+  AutoNestedPaintCount() {
+    gPaintCountStack->AppendElement(0);
+  }
+  ~AutoNestedPaintCount() {
+    gPaintCountStack->RemoveElementAt(gPaintCountStack->Length() - 1);
+  }
+};
+
 #endif
 
 nsIFrame*
@@ -3086,6 +3100,17 @@ nsLayoutUtils::PaintFrame(nsRenderingContext* aRenderingContext, nsIFrame* aFram
   PROFILER_LABEL("nsLayoutUtils", "PaintFrame",
     js::ProfileEntry::Category::GRAPHICS);
 
+#ifdef MOZ_DUMP_PAINTING
+  if (!gPaintCountStack) {
+    gPaintCountStack = new nsTArray<int>();
+    ClearOnShutdown(&gPaintCountStack);
+
+    gPaintCountStack->AppendElement(0);
+  }
+  ++gPaintCountStack->LastElement();
+  AutoNestedPaintCount nestedPaintCount;
+#endif
+
   if (aFlags & PAINT_WIDGET_LAYERS) {
     nsView* view = aFrame->GetView();
     if (!(view && view->GetWidget() && GetDisplayRootFrame(aFrame) == aFrame)) {
@@ -3277,8 +3302,10 @@ nsLayoutUtils::PaintFrame(nsRenderingContext* aRenderingContext, nsIFrame* aFram
       // Include the process ID in the dump file name, to make sure that in an
       // e10s setup different processes don't clobber each other's dump files.
       string.AppendInt(getpid());
-      string.AppendLiteral("-");
-      string.AppendInt(gPaintCount);
+      for (int paintCount : *gPaintCountStack) {
+        string.AppendLiteral("-");
+        string.AppendInt(paintCount);
+      }
       string.AppendLiteral(".html");
       gfxUtils::sDumpPaintFile = fopen(string.BeginReading(), "w");
     } else {
@@ -3366,7 +3393,6 @@ nsLayoutUtils::PaintFrame(nsRenderingContext* aRenderingContext, nsIFrame* aFram
       fclose(gfxUtils::sDumpPaintFile);
     }
     gfxUtils::sDumpPaintFile = savedDumpFile;
-    gPaintCount++;
 #endif
 
     std::stringstream lsStream;