VideoCaptureManager opens/closes, starts/stops and enumerates video capture devices. VideoCapture...

content/browser/media_stream/video_capture_manager.cc

+// 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 "content/browser/media_stream/video_capture_manager.h"
+
+#include "base/memory/scoped_ptr.h"
+#include "content/browser/browser_thread.h"
+#include "media/video/capture/fake_video_capture_device.h"
+#include "media/video/capture/video_capture_device.h"
+
+namespace media_stream {
+
+// Starting id for the first capture session

[brettw, 2011/05/24 20:49:30]

All of your comments should be complete sentences with periods at the end.

[wjia(left Chromium), 2011/05/31 18:47:03]

Done.

+enum { kFirstSessionId = 2};

[brettw, 2011/05/24 20:49:30]

This value is a bit mysterious. The comment should probably say why you picked
this value or use 1.

[wjia(left Chromium), 2011/05/31 18:47:03]

change it to kFirstSessionId = VideoCaptureManager::kStartOpenSessionId + 1.

+
+static ::base::LazyInstance<VideoCaptureManager> g_video_capture_manager(
+    base::LINKER_INITIALIZED);
+
+VideoCaptureManager* VideoCaptureManager::Get() {
+  return g_video_capture_manager.Pointer();
+}
+
+VideoCaptureManager::VideoCaptureManager()
+  : vc_device_thread_("VideoCaptureManagerThread"),
+    listener_(NULL),
+    new_capture_session_id_(kFirstSessionId),
+    devices_(),
+    use_fake_device_(false) {
+  vc_device_thread_.Start();
+}
+
+VideoCaptureManager::~VideoCaptureManager() {
+  vc_device_thread_.Stop();
+}
+
+bool VideoCaptureManager::Register(MediaStreamProviderListener* listener) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  DCHECK(!listener_);
+  listener_ = listener;
+  return true;
+}
+
+void VideoCaptureManager::Unregister() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  listener_ = NULL;
+}
+
+void VideoCaptureManager::EnumerateDevices() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  DCHECK(listener_);
+
+  vc_device_thread_.message_loop()->PostTask(
+      FROM_HERE,
+      NewRunnableMethod(this,
+                        &VideoCaptureManager::OnEnumerateDevices));
+}
+
+MediaCaptureSessionId VideoCaptureManager::Open(
+    const MediaCaptureDeviceInfo& device) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  DCHECK(listener_);
+
+  // Generate a new id for this device
+  MediaCaptureSessionId video_capture_session_id = new_capture_session_id_++;
+
+  vc_device_thread_.message_loop()->PostTask(
+      FROM_HERE,
+      NewRunnableMethod(this,
+                        &VideoCaptureManager::OnOpen,
+                        video_capture_session_id,
+                        device));
+
+  return video_capture_session_id;
+}
+
+void VideoCaptureManager::Close(MediaCaptureSessionId capture_session_id) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  DCHECK(listener_);
+
+  vc_device_thread_.message_loop()->PostTask(
+      FROM_HERE,
+      NewRunnableMethod(this,
+                        &VideoCaptureManager::OnClose,
+                        capture_session_id));
+}
+
+void VideoCaptureManager::Start(
+    const media::VideoCaptureParams& capture_params,
+    media::VideoCaptureDevice::EventHandler* video_capture_receiver) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+
+  vc_device_thread_.message_loop()->PostTask(
+      FROM_HERE,
+      NewRunnableMethod(this,
+                        &VideoCaptureManager::OnStart,
+                        capture_params,
+                        video_capture_receiver));
+}
+
+void VideoCaptureManager::Stop(
+    const media::VideoCaptureSessionId capture_session_id, Task* stopped_task) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+
+  vc_device_thread_.message_loop()->PostTask(
+      FROM_HERE,
+      NewRunnableMethod(this,
+                        &VideoCaptureManager::OnStop,
+                        capture_session_id,
+                        stopped_task));
+}
+
+void VideoCaptureManager::UseFakeDevice() {
+  use_fake_device_ = true;
+}
+
+MessageLoop* VideoCaptureManager::GetMessageLoop() {
+  return vc_device_thread_.message_loop();
+}
+
+void VideoCaptureManager::OnEnumerateDevices() {
+  DCHECK(IsOnCaptureDeviceThread());
+
+  scoped_ptr<media::VideoCaptureDevice::Names> device_names(
+      new media::VideoCaptureDevice::Names());
+  GetAvailableDevices(device_names.get());
+
+  MediaCaptureDevices devices;
+  for (media::VideoCaptureDevice::Names::iterator it =
+      device_names.get()->begin(); it != device_names.get()->end(); ++it) {

[brettw, 2011/05/24 20:49:30]

Wrapped lines should be indented to inside the (. Normalyy we would indent this
an extra 4 spaces to differentiate it from the beginning of the next "argument"
(so under the "a").

[wjia(left Chromium), 2011/05/31 18:47:03]

Done.

+    bool opened = DeviceOpened(*it);
+    devices.push_back(MediaCaptureDeviceInfo(kVideoCapture, it->device_name,
+                                             it->unique_id, opened));
+  }
+
+  // Let the listener know the result

[brettw, 2011/05/24 20:49:30]

This comment and the next one don't add any value, I'd remove them.

[wjia(left Chromium), 2011/05/31 18:47:03]

Done.

+  PostOnDevicesEnumerated(devices);
+
+  // Clean-up
+  devices.clear();
+  device_names.get()->clear();
+}
+
+void VideoCaptureManager::OnOpen(MediaCaptureSessionId capture_session_id,
+                                 const MediaCaptureDeviceInfo device) {
+  DCHECK(IsOnCaptureDeviceThread());
+  DCHECK(devices_.find(capture_session_id) == devices_.end());
+
+  // Check if another session has already opened this device, only one user per
+  // device is supported.
+  if (DeviceOpened(device)) {
+    PostOnError(capture_session_id, kDeviceAlreadyInUse);
+    return;
+  }
+
+  // Open the device
+  media::VideoCaptureDevice::Name vc_device_name;
+  vc_device_name.device_name = device.name;
+  vc_device_name.unique_id = device.device_id;
+
+  media::VideoCaptureDevice* video_capture_device = NULL;
+  if (!use_fake_device_) {
+    video_capture_device = media::VideoCaptureDevice::Create(vc_device_name);
+  } else {
+    video_capture_device =
+        media::FakeVideoCaptureDevice::Create(vc_device_name);
+  }
+  if (video_capture_device == NULL) {
+    PostOnError(capture_session_id, kDeviceNotAvailable);
+    return;
+  }
+
+  devices_[capture_session_id] = video_capture_device;
+  PostOnOpened(capture_session_id);
+}
+
+void VideoCaptureManager::OnClose(
+    MediaCaptureSessionId capture_session_id) {
+  DCHECK(IsOnCaptureDeviceThread());
+
+  VideoCaptureDevices::iterator it = devices_.find(capture_session_id);
+  if (it != devices_.end()) {
+    // Deallocate (if not done already) and delete the device
+    media::VideoCaptureDevice* video_capture_device = it->second;
+    video_capture_device->DeAllocate();
+    delete video_capture_device;
+    devices_.erase(it);
+  }
+
+  PostOnClosed(capture_session_id);
+}
+
+void VideoCaptureManager::OnStart(
+    const media::VideoCaptureParams capture_params,
+    media::VideoCaptureDevice::EventHandler* video_capture_receiver) {
+  DCHECK(IsOnCaptureDeviceThread());
+
+  // Solution for not using MediaStreamManager
+  // This session id won't be returned by Open()
+  if (capture_params.session_id == kStartOpenSessionId) {
+    // Start() is called without using Open(), we need to open a device
+    scoped_ptr<media::VideoCaptureDevice::Names> device_names(
+        new media::VideoCaptureDevice::Names());
+    GetAvailableDevices(device_names.get());
+
+    MediaCaptureDeviceInfo device(kVideoCapture,
+                                  device_names.get()->front().device_name,
+                                  device_names.get()->front().unique_id, false);
+
+    // Call OnOpen to open using the first device in the list
+    OnOpen(capture_params.session_id, device);
+  }
+
+  VideoCaptureDevices::iterator it = devices_.find(capture_params.session_id);
+  if (it == devices_.end()) {
+    // Invalid session id
+    video_capture_receiver->OnError();
+    return;
+  }
+  media::VideoCaptureDevice* video_capture_device = it->second;
+
+  // Possible errors are signaled to video_capture_receiver by
+  // video_capture_device. video_capture_receiver to perform actions.
+  video_capture_device->Allocate(capture_params.width, capture_params.height,
+                                 capture_params.frame_per_second,
+                                 video_capture_receiver);
+  video_capture_device->Start();
+}
+
+void VideoCaptureManager::OnStop(
+    const media::VideoCaptureSessionId capture_session_id,
+    Task* stopped_task) {
+  DCHECK(IsOnCaptureDeviceThread());
+
+  VideoCaptureDevices::iterator it = devices_.find(capture_session_id);
+  if (it != devices_.end()) {
+    media::VideoCaptureDevice* video_capture_device = it->second;
+    // Possible errors are signaled to video_capture_receiver by
+    // video_capture_device. video_capture_receiver to perform actions.
+    video_capture_device->Stop();
+    video_capture_device->DeAllocate();
+  }
+
+  if (stopped_task) {
+    stopped_task->Run();
+    delete stopped_task;
+  }
+
+  if (capture_session_id == kStartOpenSessionId) {
+    // This device was opened from Start(), not Open(). Close it!
+    OnClose(capture_session_id);
+  }
+}
+
+void VideoCaptureManager::OnOpened(
+    MediaCaptureSessionId capture_session_id) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  if (listener_ == NULL) {
+    // Listener has been removed
+    return;
+  }
+  listener_->Opened(kVideoCapture, capture_session_id);
+}
+
+void VideoCaptureManager::OnClosed(
+    MediaCaptureSessionId capture_session_id) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  if (listener_ == NULL) {
+    // Listener has been removed
+    return;
+  }
+  listener_->Closed(kVideoCapture, capture_session_id);
+}
+
+void VideoCaptureManager::OnDevicesEnumerated(
+    const MediaCaptureDevices& devices) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  if (listener_ == NULL) {
+    // Listener has been removed
+    return;
+  }
+  listener_->DevicesEnumerated(kVideoCapture, devices);
+}
+
+void VideoCaptureManager::OnError(MediaCaptureSessionId capture_session_id,
+                                  MediaStreamProviderError error) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  if (listener_ == NULL) {
+    // Listener has been removed
+    return;
+  }
+  listener_->Error(kVideoCapture, capture_session_id, error);
+}
+
+void VideoCaptureManager::PostOnOpened(
+    MediaCaptureSessionId capture_session_id) {
+  DCHECK(IsOnCaptureDeviceThread());
+  BrowserThread::PostTask(BrowserThread::IO,
+                          FROM_HERE,
+                          NewRunnableMethod(this,
+                                            &VideoCaptureManager::OnOpened,
+                                            capture_session_id));
+}
+
+void VideoCaptureManager::PostOnClosed(
+    MediaCaptureSessionId capture_session_id) {
+  DCHECK(IsOnCaptureDeviceThread());
+  BrowserThread::PostTask(BrowserThread::IO,
+                            FROM_HERE,
+                            NewRunnableMethod(this,
+                                              &VideoCaptureManager::OnClosed,
+                                              capture_session_id));
+}
+
+void VideoCaptureManager::PostOnDevicesEnumerated(MediaCaptureDevices devices) {
+  DCHECK(IsOnCaptureDeviceThread());
+
+  BrowserThread::PostTask(BrowserThread::IO,
+                          FROM_HERE,
+                          NewRunnableMethod(
+                              this,
+                              &VideoCaptureManager::OnDevicesEnumerated,
+                              devices));
+}
+
+void VideoCaptureManager::PostOnError(MediaCaptureSessionId capture_session_id,
+                                      MediaStreamProviderError error) {
+  // Don't check thread here, can be called from both IO thread and device
+  // thread.
+  BrowserThread::PostTask(BrowserThread::IO,
+                          FROM_HERE,
+                          NewRunnableMethod(this,
+                                            &VideoCaptureManager::OnError,
+                                            capture_session_id,
+                                            error));
+}
+
+bool VideoCaptureManager::IsOnCaptureDeviceThread() const {
+  return MessageLoop::current() == vc_device_thread_.message_loop();
+}
+
+void VideoCaptureManager::GetAvailableDevices(
+    media::VideoCaptureDevice::Names* device_names) {
+  DCHECK(IsOnCaptureDeviceThread());
+
+  if (!use_fake_device_) {
+     media::VideoCaptureDevice::GetDeviceNames(device_names);
+  } else {
+    media::FakeVideoCaptureDevice::GetDeviceNames(device_names);
+  }
+}
+
+bool VideoCaptureManager::DeviceOpened(
+    const media::VideoCaptureDevice::Name& device_name) {
+  DCHECK(IsOnCaptureDeviceThread());
+
+  for (VideoCaptureDevices::iterator it = devices_.begin();
+      it != devices_.end();
+      ++it) {
+    if (device_name.unique_id == it->second->device_name().unique_id) {
+      // We've found the device!
+      return true;
+    }
+  }
+  return false;
+}
+
+bool VideoCaptureManager::DeviceOpened(
+    const MediaCaptureDeviceInfo& device_info) {
+  DCHECK(IsOnCaptureDeviceThread());
+
+  for (VideoCaptureDevices::iterator it = devices_.begin();
+      it != devices_.end();
+      it++) {
+    if (device_info.device_id == it->second->device_name().unique_id) {
+      return true;
+    }
+  }
+  return false;
+}
+
+}  // namespace media