Bug 657780. Silence pldhash warnings by shrinking ThebesLayerItemsEntry. r=tnikkel

layout/base/FrameLayerBuilder.cpp

@@ -715,28 +715,19 @@ FrameLayerBuilder::GetOldLayerFor(nsIFrame* aFrame, PRUint32 aDisplayItemKey)
 
 /**
  * Invalidate aRegion in aLayer. aLayer is in the coordinate system
- * *after* aTransform has been applied, so we need to
+ * *after* aTranslation has been applied, so we need to
  * apply the inverse of that transform before calling InvalidateRegion.
- * Currently we assume that the transform is just an integer translation,
- * since that's all we need for scrolling.
  */
 static void
 InvalidatePostTransformRegion(ThebesLayer* aLayer, const nsIntRegion& aRegion,
-                              const gfx3DMatrix& aTransform)
+                              const nsIntPoint& aTranslation)
 {
-  gfxMatrix transform;
-  if (aTransform.Is2D(&transform)) {
-    NS_ASSERTION(!transform.HasNonIntegerTranslation(),
-                 "Matrix not just an integer translation?");
-    // Convert the region from the coordinates of the container layer
-    // (relative to the snapped top-left of the display list reference frame)
-    // to the ThebesLayer's own coordinates
-    nsIntRegion rgn = aRegion;
-    rgn.MoveBy(-nsIntPoint(PRInt32(transform.x0), PRInt32(transform.y0)));
-    aLayer->InvalidateRegion(rgn);
-  } else {
-    NS_ERROR("Only 2D transformations currently supported");
-  }
+  // Convert the region from the coordinates of the container layer
+  // (relative to the snapped top-left of the display list reference frame)
+  // to the ThebesLayer's own coordinates
+  nsIntRegion rgn = aRegion;
+  rgn.MoveBy(-aTranslation);
+  aLayer->InvalidateRegion(rgn);
 }
 
 already_AddRefed<ColorLayer>
@@ -783,6 +774,18 @@ ContainerState::CreateOrRecycleImageLayer()
   return layer.forget();
 }
 
+static nsIntPoint
+GetTranslationForThebesLayer(ThebesLayer* aLayer)
+{
+  gfxMatrix transform;
+  if (!aLayer->GetTransform().Is2D(&transform) &&
+      transform.HasNonIntegerTranslation()) {
+    NS_ERROR("ThebesLayers should have integer translations only");
+    return nsIntPoint(0, 0);
+  }
+  return nsIntPoint(PRInt32(transform.x0), PRInt32(transform.y0));
+}
+
 already_AddRefed<ThebesLayer>
 ContainerState::CreateOrRecycleThebesLayer(nsIFrame* aActiveScrolledRoot)
 {
@@ -809,7 +812,7 @@ ContainerState::CreateOrRecycleThebesLayer(nsIFrame* aActiveScrolledRoot)
       layer->InvalidateRegion(invalidate);
     } else {
       InvalidatePostTransformRegion(layer, mInvalidThebesContent,
-                                    layer->GetTransform());
+                                    GetTranslationForThebesLayer(layer));
     }
     // We do not need to Invalidate these areas in the widget because we
     // assume the caller of InvalidateThebesLayerContents has ensured
@@ -824,7 +827,7 @@ ContainerState::CreateOrRecycleThebesLayer(nsIFrame* aActiveScrolledRoot)
         new ThebesDisplayItemLayerUserData());
   }
 
-  mBuilder->LayerBuilder()->SaveLastPaintTransform(layer, layer->GetTransform());
+  mBuilder->LayerBuilder()->SaveLastPaintOffset(layer);
 
   // Set up transform so that 0,0 in the Thebes layer corresponds to the
   // (pixel-snapped) top-left of the aActiveScrolledRoot.
@@ -1424,12 +1427,13 @@ ContainerState::InvalidateForLayerChange(nsDisplayItem* aItem, Layer* aNewLayer)
     ThebesLayer* t = oldLayer->AsThebesLayer();
     if (t) {
       InvalidatePostTransformRegion(t, r,
-              mBuilder->LayerBuilder()->GetLastPaintTransform(t));
+          mBuilder->LayerBuilder()->GetLastPaintOffset(t));
     }
     if (aNewLayer) {
       ThebesLayer* newLayer = aNewLayer->AsThebesLayer();
       if (newLayer) {
-        InvalidatePostTransformRegion(newLayer, r, newLayer->GetTransform());
+        InvalidatePostTransformRegion(newLayer, r,
+            GetTranslationForThebesLayer(newLayer));
       }
     }
 
@@ -1484,23 +1488,22 @@ FrameLayerBuilder::AddLayerDisplayItem(Layer* aLayer,
   }
 }
 
-const gfx3DMatrix&
-FrameLayerBuilder::GetLastPaintTransform(ThebesLayer* aLayer)
+nsIntPoint
+FrameLayerBuilder::GetLastPaintOffset(ThebesLayer* aLayer)
 {
   ThebesLayerItemsEntry* entry = mThebesLayerItems.PutEntry(aLayer);
-  if (entry && entry->mHasExplicitLastPaintTransform)
-    return entry->mLastPaintTransform;
-  return aLayer->GetTransform();
+  if (entry && entry->mHasExplicitLastPaintOffset)
+    return entry->mLastPaintOffset;
+  return GetTranslationForThebesLayer(aLayer);
 }
 
 void
-FrameLayerBuilder::SaveLastPaintTransform(ThebesLayer* aLayer,
-                                          const gfx3DMatrix& aMatrix)
+FrameLayerBuilder::SaveLastPaintOffset(ThebesLayer* aLayer)
 {
   ThebesLayerItemsEntry* entry = mThebesLayerItems.PutEntry(aLayer);
   if (entry) {
-    entry->mLastPaintTransform = aMatrix;
-    entry->mHasExplicitLastPaintTransform = PR_TRUE;
+    entry->mLastPaintOffset = GetTranslationForThebesLayer(aLayer);
+    entry->mHasExplicitLastPaintOffset = PR_TRUE;
   }
 }
 
@@ -1846,18 +1849,11 @@ FrameLayerBuilder::DrawThebesLayer(ThebesLayer* aLayer,
     aContext->Fill();
   }
 
-  gfxMatrix transform;
-  if (!aLayer->GetTransform().Is2D(&transform)) {
-    NS_ERROR("non-2D transform in our Thebes layer!");
-    return;
-  }
-  NS_ASSERTION(!transform.HasNonIntegerTranslation(),
-               "Matrix not just an integer translation?");
   // make the origin of the context coincide with the origin of the
   // ThebesLayer
-  gfxContextMatrixAutoSaveRestore saveMatrix(aContext); 
-  aContext->Translate(-gfxPoint(transform.x0, transform.y0));
-  nsIntPoint offset(PRInt32(transform.x0), PRInt32(transform.y0));
+  gfxContextMatrixAutoSaveRestore saveMatrix(aContext);
+  nsIntPoint offset = GetTranslationForThebesLayer(aLayer);
+  aContext->Translate(-gfxPoint(offset.x, offset.y));
 
   nsPresContext* presContext = containerLayerFrame->PresContext();
   PRInt32 appUnitsPerDevPixel = presContext->AppUnitsPerDevPixel();

layout/base/FrameLayerBuilder.h

@@ -297,15 +297,16 @@ public:
   static PRBool HasRetainedLayerFor(nsIFrame* aFrame, PRUint32 aDisplayItemKey);
 
   /**
-   * Save aMatrix as the transform that was in aLayer when we last painted.
+   * Save transform that was in aLayer when we last painted. It must be an integer
+   * translation.
    */
-  void SaveLastPaintTransform(ThebesLayer* aLayer, const gfx3DMatrix& aMatrix);
+  void SaveLastPaintOffset(ThebesLayer* aLayer);
   /**
-   * Get the transform that was in aLayer when we last painted. It's either
+   * Get the translation transform that was in aLayer when we last painted. It's either
    * the transform saved by SaveLastPaintTransform, or else the transform
-   * that's currently in the layer.
+   * that's currently in the layer (which must be an integer translation).
    */
-  const gfx3DMatrix& GetLastPaintTransform(ThebesLayer* aLayer);
+  nsIntPoint GetLastPaintOffset(ThebesLayer* aLayer);
 
   /**
    * Clip represents the intersection of an optional rectangle with a
@@ -451,7 +452,7 @@ protected:
   public:
     ThebesLayerItemsEntry(const ThebesLayer *key) :
         nsPtrHashKey<ThebesLayer>(key), mContainerLayerFrame(nsnull),
-        mHasExplicitLastPaintTransform(PR_FALSE) {}
+        mHasExplicitLastPaintOffset(PR_FALSE) {}
     ThebesLayerItemsEntry(const ThebesLayerItemsEntry &toCopy) :
       nsPtrHashKey<ThebesLayer>(toCopy.mKey), mItems(toCopy.mItems)
     {
@@ -460,10 +461,10 @@ protected:
 
     nsTArray<ClippedDisplayItem> mItems;
     nsIFrame* mContainerLayerFrame;
-    // The transform set on this ThebesLayer before we started updating the
+    // The translation set on this ThebesLayer before we started updating the
     // layer tree.
-    gfx3DMatrix mLastPaintTransform;
-    PRPackedBool mHasExplicitLastPaintTransform;
+    nsIntPoint mLastPaintOffset;
+    PRPackedBool mHasExplicitLastPaintOffset;
 
     enum { ALLOW_MEMMOVE = PR_TRUE };
   };