text: // Copyright 2013 The Chromium Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #include "cc/raster/zero_copy_raster_buffer_provider.h"
  
  #include <stdint.h>
  
  #include <algorithm>
  
  #include "base/macros.h"
  #include "base/memory/ptr_util.h"
  #include "base/strings/stringprintf.h"
  #include "base/trace_event/trace_event.h"
  #include "base/trace_event/trace_event_argument.h"
  #include "cc/debug/traced_value.h"
  #include "cc/resources/platform_color.h"
  #include "cc/resources/resource.h"
  #include "ui/gfx/buffer_format_util.h"
  #include "ui/gfx/gpu_memory_buffer.h"
  
  namespace cc {
  namespace {
  
  class RasterBufferImpl : public RasterBuffer {
   public:
    RasterBufferImpl(ResourceProvider* resource_provider,
                     const Resource* resource)
        : lock_(resource_provider, resource->id()), resource_(resource) {}
  
    // Overridden from RasterBuffer:
    void Playback(
        const RasterSource* raster_source,
        const gfx::Rect& raster_full_rect,
        const gfx::Rect& raster_dirty_rect,
        uint64_t new_content_id,
        const gfx::SizeF& scales,
        const RasterSource::PlaybackSettings& playback_settings) override {
      TRACE_EVENT0("cc", "ZeroCopyRasterBuffer::Playback");
      gfx::GpuMemoryBuffer* buffer = lock_.GetGpuMemoryBuffer();
      if (!buffer)
        return;
  
      DCHECK_EQ(1u, gfx::NumberOfPlanesForBufferFormat(buffer->GetFormat()));
      bool rv = buffer->Map();
      DCHECK(rv);
      DCHECK(buffer->memory(0));
      // RasterBufferProvider::PlaybackToMemory only supports unsigned strides.
      DCHECK_GE(buffer->stride(0), 0);
  
      // TODO(danakj): Implement partial raster with raster_dirty_rect.
      RasterBufferProvider::PlaybackToMemory(
          buffer->memory(0), resource_->format(), resource_->size(),
          buffer->stride(0), raster_source, raster_full_rect, raster_full_rect,
          scales, lock_.sk_color_space(), playback_settings);
      buffer->Unmap();
    }
  
   private:
    ResourceProvider::ScopedWriteLockGpuMemoryBuffer lock_;
    const Resource* resource_;
  
    DISALLOW_COPY_AND_ASSIGN(RasterBufferImpl);
  };
  
  }  // namespace
  
  // static
  std::unique_ptr<RasterBufferProvider> ZeroCopyRasterBufferProvider::Create(
      ResourceProvider* resource_provider,
      ResourceFormat preferred_tile_format) {
    return base::WrapUnique<RasterBufferProvider>(
        new ZeroCopyRasterBufferProvider(resource_provider,
                                         preferred_tile_format));
  }
  
  ZeroCopyRasterBufferProvider::ZeroCopyRasterBufferProvider(
      ResourceProvider* resource_provider,
      ResourceFormat preferred_tile_format)
      : resource_provider_(resource_provider),
        preferred_tile_format_(preferred_tile_format) {}
  
  ZeroCopyRasterBufferProvider::~ZeroCopyRasterBufferProvider() {}
  
  std::unique_ptr<RasterBuffer>
  ZeroCopyRasterBufferProvider::AcquireBufferForRaster(
      const Resource* resource,
      uint64_t resource_content_id,
      uint64_t previous_content_id) {
    return base::WrapUnique<RasterBuffer>(
        new RasterBufferImpl(resource_provider_, resource));
  }
  
  void ZeroCopyRasterBufferProvider::ReleaseBufferForRaster(
      std::unique_ptr<RasterBuffer> buffer) {
    // Nothing to do here. RasterBufferImpl destructor cleans up after itself.
  }
  
  void ZeroCopyRasterBufferProvider::OrderingBarrier() {
    // No need to sync resources as this provider does not use GL context.
  }
  
  ResourceFormat ZeroCopyRasterBufferProvider::GetResourceFormat(
      bool must_support_alpha) const {
    if (resource_provider_->IsResourceFormatSupported(preferred_tile_format_) &&
        (DoesResourceFormatSupportAlpha(preferred_tile_format_) ||
         !must_support_alpha)) {
      return preferred_tile_format_;
    }
  
    return resource_provider_->best_texture_format();
  }
  
  bool ZeroCopyRasterBufferProvider::IsResourceSwizzleRequired(
      bool must_support_alpha) const {
    return ResourceFormatRequiresSwizzle(GetResourceFormat(must_support_alpha));
  }
  
  bool ZeroCopyRasterBufferProvider::CanPartialRasterIntoProvidedResource()
      const {
    return false;
  }
  
  void ZeroCopyRasterBufferProvider::Shutdown() {}
  
  }  // namespace cc
  