diff -r 000000000000 -r 6474c204b198 widget/android/AndroidDirectTexture.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/widget/android/AndroidDirectTexture.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,126 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <unistd.h>
+#include <errno.h>
+#include "AndroidDirectTexture.h"
+#include "nsRect.h"
+
+namespace mozilla {
+
+AndroidDirectTexture::AndroidDirectTexture(uint32_t width, uint32_t height, uint32_t usage,
+                                           gfxImageFormat format) :
+    mLock("AndroidDirectTexture.mLock")
+  , mNeedFlip(false)
+  , mWidth(width)
+  , mHeight(height)
+  , mFormat(format)
+  , mPendingReallocBuffer(nullptr)
+{
+  mFrontBuffer = new AndroidGraphicBuffer(width, height, usage, format);
+  mBackBuffer = new AndroidGraphicBuffer(width, height, usage, format);
+}
+
+AndroidDirectTexture::~AndroidDirectTexture()
+{
+  if (mFrontBuffer) {
+    delete mFrontBuffer;
+    mFrontBuffer = nullptr;
+  }
+
+  if (mBackBuffer) {
+    delete mBackBuffer;
+    mBackBuffer = nullptr;
+  }
+}
+
+void
+AndroidDirectTexture::ReallocPendingBuffer()
+{
+  // We may have reallocated while the current back buffer was being
+  // used as the front buffer. If we have such a reallocation pending
+  // and the current back buffer is the target buffer, do it now.
+  //
+  // It is assumed that mLock is already acquired
+  if (mPendingReallocBuffer == mBackBuffer) {
+    mBackBuffer->Reallocate(mWidth, mHeight, mFormat);
+    mPendingReallocBuffer = nullptr;
+  }
+}
+
+bool
+AndroidDirectTexture::Lock(uint32_t aUsage, unsigned char **bits)
+{
+  nsIntRect rect(0, 0, mWidth, mHeight);
+  return Lock(aUsage, rect, bits);
+}
+
+bool
+AndroidDirectTexture::Lock(uint32_t aUsage, const nsIntRect& aRect, unsigned char **bits)
+{
+  mLock.Lock();
+  ReallocPendingBuffer();
+
+  int result;
+  while ((result = mBackBuffer->Lock(aUsage, aRect, bits)) == -EBUSY) {
+    usleep(1000); // 1ms
+  }
+
+  return result == 0;
+}
+
+bool
+AndroidDirectTexture::Unlock(bool aFlip)
+{
+  if (aFlip) {
+    mNeedFlip = true;
+  }
+
+  bool result = mBackBuffer->Unlock();
+  mLock.Unlock();
+
+  return result;
+}
+
+bool
+AndroidDirectTexture::Reallocate(uint32_t aWidth, uint32_t aHeight) {
+  return Reallocate(aWidth, aHeight, mFormat);
+}
+
+bool
+AndroidDirectTexture::Reallocate(uint32_t aWidth, uint32_t aHeight, gfxImageFormat aFormat)
+{
+  MutexAutoLock lock(mLock);
+
+  // We only reallocate the current back buffer. The front buffer is likely
+  // in use, so we'll reallocate it on the first Lock() after it is rotated
+  // to the back.
+  bool result = mBackBuffer->Reallocate(aWidth, aHeight, aFormat);
+  if (result) {
+    mPendingReallocBuffer = mFrontBuffer;
+
+    mWidth = aWidth;
+    mHeight = aHeight;
+  }
+
+  return result;
+}
+
+bool
+AndroidDirectTexture::Bind()
+{
+  MutexAutoLock lock(mLock);
+
+  if (mNeedFlip) {
+    AndroidGraphicBuffer* tmp = mBackBuffer;
+    mBackBuffer = mFrontBuffer;
+    mFrontBuffer = tmp;
+    mNeedFlip = false;
+  }
+
+  return mFrontBuffer->Bind();
+}
+
+} /* mozilla */