From f62c69e9d3990dff71dcf7539d6b73d5a9c6d265 Mon Sep 17 00:00:00 2001
From: Bas Schouten <bschouten@mozilla.com>
Date: Thu, 20 Nov 2014 20:48:01 +0000
Subject: [PATCH] Bug 892910: Deal with newSize becoming empty in
 CreatePartialBitmapForSurface. r=BenWa

This patch deals with the situation where newSize becomes empty and causes a division by 0 in the current code. It also ensures all the callers will abort any potential drawing when CreatePartialBitmapForSurface returns a nullptr.
---
 gfx/2d/DrawTargetD2D.cpp  |  4 +++-
 gfx/2d/DrawTargetD2D1.cpp | 24 +++++++++++++++++++++++-
 gfx/2d/HelpersD2D.h       |  8 ++++++--
 3 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/gfx/2d/DrawTargetD2D.cpp b/gfx/2d/DrawTargetD2D.cpp
index 0f7036c0fdc8..0ff00370a524 100644
--- a/gfx/2d/DrawTargetD2D.cpp
+++ b/gfx/2d/DrawTargetD2D.cpp
@@ -2417,7 +2417,9 @@ DrawTargetD2D::CreateBrushForPattern(const Pattern &aPattern, Float aAlpha)
 
         bitmap = CreatePartialBitmapForSurface(dataSurf, mTransform, mSize, pat->mExtendMode, mat, mRT, &sourceRect);
         if (!bitmap) {
-          return nullptr;
+          RefPtr<ID2D1SolidColorBrush> colBrush;
+          mRT->CreateSolidColorBrush(D2D1::ColorF(0, 0), byRef(colBrush));
+          return colBrush.forget();
         }
       }
       break;
diff --git a/gfx/2d/DrawTargetD2D1.cpp b/gfx/2d/DrawTargetD2D1.cpp
index 42cc4b471d21..49bed2767d8f 100644
--- a/gfx/2d/DrawTargetD2D1.cpp
+++ b/gfx/2d/DrawTargetD2D1.cpp
@@ -191,6 +191,11 @@ DrawTargetD2D1::DrawSurfaceWithShadow(SourceSurface *aSurface,
   Matrix mat;
   RefPtr<ID2D1Image> image = GetImageForSurface(aSurface, mat, ExtendMode::CLAMP);
 
+  if (!image) {
+    gfxWarning() << "Couldn't get image for surface.";
+    return;
+  }
+
   if (!mat.IsIdentity()) {
     gfxDebug() << *this << ": At this point complex partial uploads are not supported for Shadow surfaces.";
     return;
@@ -264,12 +269,19 @@ DrawTargetD2D1::MaskSurface(const Pattern &aSource,
                             Point aOffset,
                             const DrawOptions &aOptions)
 {
-  PrepareForDrawing(aOptions.mCompositionOp, aSource);
+  MarkChanged();
 
   RefPtr<ID2D1Bitmap> bitmap;
 
   RefPtr<ID2D1Image> image = GetImageForSurface(aMask, ExtendMode::CLAMP);
 
+  if (!image) {
+    gfxWarning() << "Failed to get image for surface.";
+    return;
+  }
+
+  PrepareForDrawing(aOptions.mCompositionOp, aSource);
+
   // FillOpacityMask only works if the antialias mode is MODE_ALIASED
   mDC->SetAntialiasMode(D2D1_ANTIALIAS_MODE_ALIASED);
 
@@ -305,6 +317,11 @@ DrawTargetD2D1::CopySurface(SourceSurface *aSurface,
   Matrix mat;
   RefPtr<ID2D1Image> image = GetImageForSurface(aSurface, mat, ExtendMode::CLAMP);
 
+  if (!image) {
+    gfxWarning() << "Couldn't get image for surface.";
+    return;
+  }
+
   if (!mat.IsIdentity()) {
     gfxDebug() << *this << ": At this point complex partial uploads are not supported for CopySurface.";
     return;
@@ -1256,6 +1273,11 @@ DrawTargetD2D1::CreateBrushForPattern(const Pattern &aPattern, Float aAlpha)
 
     RefPtr<ID2D1ImageBrush> imageBrush;
     RefPtr<ID2D1Image> image = GetImageForSurface(pat->mSurface, mat, pat->mExtendMode, !pat->mSamplingRect.IsEmpty() ? &pat->mSamplingRect : nullptr);
+
+    if (!image) {
+      return CreateTransparentBlackBrush();
+    }
+
     mDC->CreateImageBrush(image,
                           D2D1::ImageBrushProperties(samplingBounds,
                                                      D2DExtend(pat->mExtendMode),
diff --git a/gfx/2d/HelpersD2D.h b/gfx/2d/HelpersD2D.h
index 99154976f3bb..9599705c9bde 100644
--- a/gfx/2d/HelpersD2D.h
+++ b/gfx/2d/HelpersD2D.h
@@ -629,14 +629,18 @@ CreatePartialBitmapForSurface(DataSourceSurface *aSurface, const Matrix &aDestin
     scaler.ScaleForSize(scaleSize);
 
     IntSize newSize = scaler.GetSize();
+
+    if (newSize.IsEmpty()) {
+      return nullptr;
+    }
     
     aRT->CreateBitmap(D2D1::SizeU(newSize.width, newSize.height),
                       scaler.GetScaledData(), scaler.GetStride(),
                       D2D1::BitmapProperties(D2DPixelFormat(aSurface->GetFormat())),
                       byRef(bitmap));
 
-    aSourceTransform.PreScale(Float(size.width / newSize.width),
-                              Float(size.height / newSize.height));
+    aSourceTransform.PreScale(Float(size.width) / newSize.width,
+                              Float(size.height) / newSize.height);
     return bitmap.forget();
   }
 }