Add a proxy for thread-hopping VideoCapture::EventHandler.

media/video/capture/video_capture_proxy.cc

Index: media/video/capture/video_capture_proxy.cc
diff --git a/media/video/capture/video_capture_proxy.cc b/media/video/capture/video_capture_proxy.cc
new file mode 100644
index 0000000000000000000000000000000000000000..98962d1fb12e21ca9e87768c60f6968b75affa7b
--- /dev/null
+++ b/media/video/capture/video_capture_proxy.cc
@@ -0,0 +1,136 @@
+// Copyright (c) 2011 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 "media/video/capture/video_capture_proxy.h"
+
+#include "base/message_loop_proxy.h"
+
+namespace {
+
+// Called on VC thread: extracts the state out of the VideoCapture, and
+// serialize it into a VideoCaptureState.
+media::VideoCaptureHandlerProxy::VideoCaptureState GetState(
+    media::VideoCapture* capture) {
+  media::VideoCaptureHandlerProxy::VideoCaptureState state;
+  state.started = capture->CaptureStarted();
+  state.width = capture->CaptureWidth();
+  state.height = capture->CaptureHeight();
+  state.frame_rate = capture->CaptureFrameRate();
+  return state;
+}
+
+}  // anonymous namespace
+
+namespace media {
+
+VideoCaptureHandlerProxy::VideoCaptureHandlerProxy(
+    VideoCapture::EventHandler* proxied)
+    : proxied_(proxied),
+      main_message_loop_(base::MessageLoopProxy::CreateForCurrentThread()) {

[wjia(left Chromium), 2011/08/02 00:10:39]

how about passing in main_message_loop as an argument? That allows more classes
to use this proxy if those classes only know their main working message loop.

[piman, 2011/08/02 01:08:55]

I did that, if that is helpful to create this class on one thread but expect it
to forward to another thread. Note however possible subtle issues with lifetime,
since this class expects that the proxied event handler outlives it.

+}
+
+VideoCaptureHandlerProxy::~VideoCaptureHandlerProxy() {
+}
+
+void VideoCaptureHandlerProxy::OnStarted(VideoCapture* capture) {
+  main_message_loop_->PostTask(FROM_HERE, NewRunnableMethod(
+        this,

[wjia(left Chromium), 2011/08/02 00:10:39]

indentation.

[piman, 2011/08/02 01:08:55]

Done (here and below).

+        &VideoCaptureHandlerProxy::OnStartedOnMainThread,
+        capture,
+        GetState(capture)));
+}
+
+void VideoCaptureHandlerProxy::OnStopped(VideoCapture* capture) {
+  main_message_loop_->PostTask(FROM_HERE, NewRunnableMethod(
+        this,
+        &VideoCaptureHandlerProxy::OnStoppedOnMainThread,
+        capture,
+        GetState(capture)));
+}
+
+void VideoCaptureHandlerProxy::OnPaused(VideoCapture* capture) {
+  main_message_loop_->PostTask(FROM_HERE, NewRunnableMethod(
+        this,
+        &VideoCaptureHandlerProxy::OnPausedOnMainThread,
+        capture,
+        GetState(capture)));
+}
+
+void VideoCaptureHandlerProxy::OnError(VideoCapture* capture, int error_code) {
+  main_message_loop_->PostTask(FROM_HERE, NewRunnableMethod(
+        this,
+        &VideoCaptureHandlerProxy::OnErrorOnMainThread,
+        capture,
+        GetState(capture),
+        error_code));
+}
+
+void VideoCaptureHandlerProxy::OnBufferReady(
+    VideoCapture* capture,
+    scoped_refptr<VideoCapture::VideoFrameBuffer> buffer) {
+  main_message_loop_->PostTask(FROM_HERE, NewRunnableMethod(
+        this,
+        &VideoCaptureHandlerProxy::OnBufferReadyOnMainThread,
+        capture,
+        GetState(capture),
+        buffer));
+}
+
+void VideoCaptureHandlerProxy::OnDeviceInfoReceived(
+    VideoCapture* capture,
+    const VideoCaptureParams& device_info) {
+  main_message_loop_->PostTask(FROM_HERE, NewRunnableMethod(
+        this,
+        &VideoCaptureHandlerProxy::OnDeviceInfoReceivedOnMainThread,
+        capture,
+        GetState(capture),
+        device_info));
+}
+
+void VideoCaptureHandlerProxy::OnStartedOnMainThread(
+    VideoCapture* capture,
+    const VideoCaptureState& state) {
+  state_ = state;
+  proxied_->OnStarted(capture);
+}
+
+void VideoCaptureHandlerProxy::OnStoppedOnMainThread(
+    VideoCapture* capture,
+    const VideoCaptureState& state) {
+  state_ = state;
+  proxied_->OnStopped(capture);
+}
+
+void VideoCaptureHandlerProxy::OnPausedOnMainThread(
+    VideoCapture* capture,
+    const VideoCaptureState& state) {
+  state_ = state;
+  proxied_->OnPaused(capture);
+}
+
+void VideoCaptureHandlerProxy::OnErrorOnMainThread(
+    VideoCapture* capture,
+    const VideoCaptureState& state,
+    int error_code) {
+  state_ = state;
+  proxied_->OnError(capture, error_code);
+}
+
+void VideoCaptureHandlerProxy::OnBufferReadyOnMainThread(
+    VideoCapture* capture,
+    const VideoCaptureState& state,
+    scoped_refptr<VideoCapture::VideoFrameBuffer> buffer) {
+  state_ = state;
+  proxied_->OnBufferReady(capture, buffer);
+}
+
+void VideoCaptureHandlerProxy::OnDeviceInfoReceivedOnMainThread(
+    VideoCapture* capture,
+    const VideoCaptureState& state,
+    const VideoCaptureParams& device_info) {
+  state_ = state;
+  proxied_->OnDeviceInfoReceived(capture, device_info);
+}
+
+}  // namespace media