gpu: Add GpuMemoryBufferFactory interface.

android_webview/browser/gpu_memory_buffer_factory_impl.cc

+// 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 "android_webview/browser/gpu_memory_buffer_factory_impl.h"
+
+#include "android_webview/public/browser/draw_gl.h"
+#include "base/logging.h"
+#include "gpu/command_buffer/client/gpu_memory_buffer.h"
+#include "ui/gfx/size.h"
+#include "ui/gl/gl_bindings.h"
+
+namespace android_webview {
+
+namespace {
+
+// Provides hardware rendering functions from the Android glue layer.
+AwDrawGLFunctionTable* g_gl_draw_functions = NULL;
+
+class GpuMemoryBufferImpl : public gpu::GpuMemoryBuffer {
+ public:
+  GpuMemoryBufferImpl(int buffer_id, gfx::Size size)
+      : buffer_id_(buffer_id),
+        size_(size),
+        mapped_(false) {
+    DCHECK(buffer_id_);
+  }
+
+  virtual ~GpuMemoryBufferImpl() {
+    g_gl_draw_functions->release_graphic_buffer(buffer_id_);
+  }
+
+  // Overridden from gpu::GpuMemoryBuffer:
+  virtual void Map(gpu::GpuMemoryBuffer::AccessMode mode,
+                   void** vaddr) OVERRIDE {
+    AwMapMode map_mode = MAP_READ_ONLY;
+    switch (mode) {
+      case GpuMemoryBuffer::READ_ONLY:
+        map_mode = MAP_READ_ONLY;
+        break;
+      case GpuMemoryBuffer::WRITE_ONLY:
+        map_mode = MAP_WRITE_ONLY;
+        break;
+      case GpuMemoryBuffer::READ_WRITE:
+        map_mode = MAP_READ_WRITE;
+        break;
+      default:
+        LOG(DFATAL) << "Unknown map mode: " << mode;
+    }
+    int err = g_gl_draw_functions->map(buffer_id_, map_mode, vaddr);
+    DCHECK(!err);
+    mapped_ = true;
+  }
+  virtual void Unmap() OVERRIDE {
+    int err = g_gl_draw_functions->unmap(buffer_id_);
+    DCHECK(!err);
+    mapped_ = false;
+  }
+  virtual bool IsMapped() OVERRIDE { return mapped_; }
+  virtual uint32 GetStride() OVERRIDE {
+    return g_gl_draw_functions->get_stride(buffer_id_);
+  }
+  virtual void* GetNativeBuffer() OVERRIDE {
+    return g_gl_draw_functions->get_native_buffer(buffer_id_);
+  }
+
+ private:
+  int buffer_id_;
+  gfx::Size size_;
+  bool mapped_;
+
+  DISALLOW_COPY_AND_ASSIGN(GpuMemoryBufferImpl);
+};
+
+}  // namespace
+
+GpuMemoryBufferFactoryImpl::GpuMemoryBufferFactoryImpl() {
+}
+
+GpuMemoryBufferFactoryImpl::~GpuMemoryBufferFactoryImpl() {
+}
+
+gpu::GpuMemoryBuffer* GpuMemoryBufferFactoryImpl::CreateGpuMemoryBuffer(
+    size_t width,
+    size_t height,
+    unsigned internalformat) {
+  // For Android WebView we assume the |internalformat| will always be
+  // GL_RGBA8_OES.
+  DCHECK_EQ(static_cast<GLenum>(GL_RGBA8_OES), internalformat);

[kaanb, 2013/07/26 05:59:13]

Checking the same condition in DCHECK and if is a bit odd. Could you move the
DCHECK within the if?

[reveman, 2013/07/26 15:40:57]

I think this is common in cases where we want a DCHECK but avoid crashing the
user. I could just make this a CHECK instead and remove the if statement if you
prefer that?

[kaanb, 2013/07/26 16:57:40]

Just making this a CHECK sounds good.

[reveman, 2013/07/26 17:57:37]

Done.

+  if (internalformat != static_cast<unsigned>(GL_RGBA8_OES))
+    return NULL;
+
+  CHECK(g_gl_draw_functions);
+  int buffer_id = g_gl_draw_functions->create_graphic_buffer(width, height);
+  if (!buffer_id)

[kaanb, 2013/07/26 05:59:13]

consider using the ternary conditional operator:

return (buffer_id) ? new GpuMemoryBufferImpl(...) : NULL;

[reveman, 2013/07/26 15:40:57]

I prefer the current code as it makes it more clear that (!buffer_id) is an
error.

+    return NULL;
+
+  return new GpuMemoryBufferImpl(buffer_id, gfx::Size(width, height));
+}
+
+// static
+void GpuMemoryBufferFactoryImpl::SetAwDrawGLFunctionTable(
+    AwDrawGLFunctionTable* table) {
+  g_gl_draw_functions = table;
+}
+
+}  // namespace android_webview