Bug 1216644 - part 3 - make BufferRecycleBin store UniquePtrs; r=jrmuizel

Changing mRecycledBuffers to store UniquePtrs instead of nsAutoArrayPtrs
opens up the possibility of a reasonable facsimile of ownership in
function signatures.

gfx/layers/ImageContainer.cpp

@@ -116,7 +116,7 @@ BufferRecycleBin::BufferRecycleBin()
 }
 
 void
-BufferRecycleBin::RecycleBuffer(uint8_t* aBuffer, uint32_t aSize)
+BufferRecycleBin::RecycleBuffer(UniquePtr<uint8_t[]> aBuffer, uint32_t aSize)
 {
   MutexAutoLock lock(mLock);
 
@@ -124,19 +124,19 @@ BufferRecycleBin::RecycleBuffer(uint8_t* aBuffer, uint32_t aSize)
     mRecycledBuffers.Clear();
   }
   mRecycledBufferSize = aSize;
-  mRecycledBuffers.AppendElement(aBuffer);
+  mRecycledBuffers.AppendElement(Move(aBuffer));
 }
 
-uint8_t*
+UniquePtr<uint8_t[]>
 BufferRecycleBin::GetBuffer(uint32_t aSize)
 {
   MutexAutoLock lock(mLock);
 
   if (mRecycledBuffers.IsEmpty() || mRecycledBufferSize != aSize)
-    return new uint8_t[aSize];
+    return MakeUnique<uint8_t[]>(aSize);
 
   uint32_t last = mRecycledBuffers.Length() - 1;
-  uint8_t* result = mRecycledBuffers[last].forget();
+  UniquePtr<uint8_t[]> result = Move(mRecycledBuffers[last]);
   mRecycledBuffers.RemoveElementAt(last);
   return result;
 }
@@ -439,7 +439,7 @@ PlanarYCbCrImage::PlanarYCbCrImage()
 RecyclingPlanarYCbCrImage::~RecyclingPlanarYCbCrImage()
 {
   if (mBuffer) {
-    mRecycleBin->RecycleBuffer(mBuffer.forget(), mBufferSize);
+    mRecycleBin->RecycleBuffer(Move(mBuffer), mBufferSize);
   }
 }
 
@@ -454,7 +454,7 @@ RecyclingPlanarYCbCrImage::SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
   //   - mImplData is not used
   // Not owned:
   // - mRecycleBin
-  size_t size = mBuffer.SizeOfExcludingThis(aMallocSizeOf);
+  size_t size = aMallocSizeOf(mBuffer.get());
 
   // Could add in the future:
   // - mBackendData (from base class)
@@ -462,7 +462,7 @@ RecyclingPlanarYCbCrImage::SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
   return size;
 }
 
-uint8_t*
+UniquePtr<uint8_t[]>
 RecyclingPlanarYCbCrImage::AllocateBuffer(uint32_t aSize)
 {
   return mRecycleBin->GetBuffer(aSize);
@@ -509,7 +509,7 @@ RecyclingPlanarYCbCrImage::CopyData(const Data& aData)
   // update buffer size
   mBufferSize = size;
 
-  mData.mYChannel = mBuffer;
+  mData.mYChannel = mBuffer.get();
   mData.mCbChannel = mData.mYChannel + mData.mYStride * mData.mYSize.height;
   mData.mCrChannel = mData.mCbChannel + mData.mCbCrStride * mData.mCbCrSize.height;
 
@@ -555,7 +555,7 @@ RecyclingPlanarYCbCrImage::AllocateAndGetNewBuffer(uint32_t aSize)
     // update buffer size
     mBufferSize = aSize;
   }
-  return mBuffer;
+  return mBuffer.get();
 }
 
 already_AddRefed<gfx::SourceSurface>

gfx/layers/ImageContainer.h

@@ -30,6 +30,7 @@
 #include "mozilla/gfx/2D.h"
 #include "nsDataHashtable.h"
 #include "mozilla/EnumeratedArray.h"
+#include "mozilla/UniquePtr.h"
 
 #ifndef XPCOM_GLUE_AVOID_NSPR
 /**
@@ -203,9 +204,9 @@ class BufferRecycleBin final {
 public:
   BufferRecycleBin();
 
-  void RecycleBuffer(uint8_t* aBuffer, uint32_t aSize);
+  void RecycleBuffer(mozilla::UniquePtr<uint8_t[]> aBuffer, uint32_t aSize);
   // Returns a recycled buffer of the right size, or allocates a new buffer.
-  uint8_t* GetBuffer(uint32_t aSize);
+  mozilla::UniquePtr<uint8_t[]> GetBuffer(uint32_t aSize);
 
 private:
   typedef mozilla::Mutex Mutex;
@@ -221,7 +222,7 @@ private:
 
   // We should probably do something to prune this list on a timer so we don't
   // eat excess memory while video is paused...
-  nsTArray<nsAutoArrayPtr<uint8_t> > mRecycledBuffers;
+  nsTArray<mozilla::UniquePtr<uint8_t[]>> mRecycledBuffers;
   // This is only valid if mRecycledBuffers is non-empty
   uint32_t mRecycledBufferSize;
 };
@@ -733,13 +734,11 @@ protected:
 
   /**
    * Return a buffer to store image data in.
-   * The default implementation returns memory that can
-   * be freed wit delete[]
    */
-  uint8_t* AllocateBuffer(uint32_t aSize);
+  mozilla::UniquePtr<uint8_t[]> AllocateBuffer(uint32_t aSize);
 
   RefPtr<BufferRecycleBin> mRecycleBin;
-  nsAutoArrayPtr<uint8_t> mBuffer;
+  mozilla::UniquePtr<uint8_t[]> mBuffer;
 };
 
 /**

gfx/layers/basic/BasicImages.cpp

@@ -12,7 +12,8 @@
 #include "gfxPlatform.h"                // for gfxPlatform, gfxImageFormat
 #include "gfxUtils.h"                   // for gfxUtils
 #include "mozilla/mozalloc.h"           // for operator delete[], etc
-#include "nsAutoPtr.h"                  // for nsRefPtr, nsAutoArrayPtr
+#include "mozilla/RefPtr.h"
+#include "mozilla/UniquePtr.h"
 #include "nsAutoRef.h"                  // for nsCountedRef
 #include "nsCOMPtr.h"                   // for already_AddRefed
 #include "nsDebug.h"                    // for NS_ERROR, NS_ASSERTION
@@ -44,7 +45,7 @@ public:
     if (mDecodedBuffer) {
       // Right now this only happens if the Image was never drawn, otherwise
       // this will have been tossed away at surface destruction.
-      mRecycleBin->RecycleBuffer(mDecodedBuffer.forget(), mSize.height * mStride);
+      mRecycleBin->RecycleBuffer(Move(mDecodedBuffer), mSize.height * mStride);
     }
   }
 
@@ -61,12 +62,12 @@ public:
   virtual size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const override
   {
     size_t size = RecyclingPlanarYCbCrImage::SizeOfExcludingThis(aMallocSizeOf);
-    size += mDecodedBuffer.SizeOfExcludingThis(aMallocSizeOf);
+    size += aMallocSizeOf(mDecodedBuffer.get());
     return size;
   }
 
 private:
-  nsAutoArrayPtr<uint8_t> mDecodedBuffer;
+  UniquePtr<uint8_t[]> mDecodedBuffer;
   gfx::IntSize mScaleHint;
   int mStride;
   bool mDelayedConversion;
@@ -125,7 +126,7 @@ BasicPlanarYCbCrImage::SetData(const Data& aData)
     return false;
   }
 
-  gfx::ConvertYCbCrToRGB(aData, format, size, mDecodedBuffer, mStride);
+  gfx::ConvertYCbCrToRGB(aData, format, size, mDecodedBuffer.get(), mStride);
   SetOffscreenFormat(iFormat);
   mSize = size;
 
@@ -154,7 +155,7 @@ BasicPlanarYCbCrImage::GetAsSourceSurface()
     // We create the target out of mDecodedBuffer, and get a snapshot from it.
     // The draw target is destroyed on scope exit and the surface owns the data.
     RefPtr<gfx::DrawTarget> drawTarget
-      = gfxPlatform::GetPlatform()->CreateDrawTargetForData(mDecodedBuffer,
+      = gfxPlatform::GetPlatform()->CreateDrawTargetForData(mDecodedBuffer.get(),
                                                             mSize,
                                                             mStride,
                                                             gfx::ImageFormatToSurfaceFormat(format));
@@ -165,7 +166,7 @@ BasicPlanarYCbCrImage::GetAsSourceSurface()
     surface = drawTarget->Snapshot();
   }
 
-  mRecycleBin->RecycleBuffer(mDecodedBuffer.forget(), mSize.height * mStride);
+  mRecycleBin->RecycleBuffer(Move(mDecodedBuffer), mSize.height * mStride);
 
   mSourceSurface = surface;
   return surface.forget();