VideoCaptureDeviceFactory: Change device enumeration to callback + QTKit enumerates in UI thread.

content/browser/renderer_host/media/video_capture_manager.h

 // Copyright (c) 2012 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.
 
 // VideoCaptureManager is used to open/close, start/stop, enumerate available
 // video capture devices, and manage VideoCaptureController's.
 // All functions are expected to be called from Browser::IO thread. Some helper
 // functions (*OnDeviceThread) will dispatch operations to the device thread.
 // VideoCaptureManager will open OS dependent instances of VideoCaptureDevice.
 // A device can only be opened once.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_MEDIA_VIDEO_CAPTURE_MANAGER_H_
 #define CONTENT_BROWSER_RENDERER_HOST_MEDIA_VIDEO_CAPTURE_MANAGER_H_
 
 #include <map>
 #include <set>
 #include <string>
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
+#include "base/message_loop/message_loop.h"
 #include "base/process/process_handle.h"
+#include "base/timer/elapsed_timer.h"
 #include "content/browser/renderer_host/media/media_stream_provider.h"
 #include "content/browser/renderer_host/media/video_capture_controller_event_handler.h"
 #include "content/common/content_export.h"
 #include "content/common/media/media_stream_options.h"
 #include "media/video/capture/video_capture_device.h"
 #include "media/video/capture/video_capture_device_factory.h"
 #include "media/video/capture/video_capture_types.h"
 
 namespace content {
 class VideoCaptureController;
@@ skipping 84 matching lines @@
     DeviceInfo();
     DeviceInfo(const media::VideoCaptureDevice::Name& name,
                const media::VideoCaptureFormats& supported_formats);
     ~DeviceInfo();
 
     media::VideoCaptureDevice::Name name;
     media::VideoCaptureFormats supported_formats;
   };
   typedef std::vector<DeviceInfo> DeviceInfos;
 
-  // Check to see if |entry| has no clients left on its controller. If so,
+  // Checks to see if |entry| has no clients left on its controller. If so,
   // remove it from the list of devices, and delete it asynchronously. |entry|
   // may be freed by this function.
   void DestroyDeviceEntryIfNoClients(DeviceEntry* entry);
 
   // Helpers to report an event to our Listener.
   void OnOpened(MediaStreamType type,
                 media::VideoCaptureSessionId capture_session_id);
   void OnClosed(MediaStreamType type,
                 media::VideoCaptureSessionId capture_session_id);
-  void OnDevicesInfoEnumerated(
-      MediaStreamType stream_type,
-      const DeviceInfos& new_devices_info_cache);
+  void OnDevicesInfoEnumerated(MediaStreamType stream_type,
+                               base::ElapsedTimer* timer,
+                               const DeviceInfos& new_devices_info_cache);
 
-  // Find a DeviceEntry by its device ID and type, if it is already opened.
+  // Finds a DeviceEntry by its device ID and type, if it is already opened.
   DeviceEntry* GetDeviceEntryForMediaStreamDevice(
       const MediaStreamDevice& device_info);
 
-  // Find a DeviceEntry entry for the indicated session, creating a fresh one
+  // Finds a DeviceEntry entry for the indicated session, creating a fresh one
   // if necessary. Returns NULL if the session id is invalid.
   DeviceEntry* GetOrCreateDeviceEntry(
       media::VideoCaptureSessionId capture_session_id);
 
-  // Find the DeviceEntry that owns a particular controller pointer.
+  // Finds the DeviceEntry that owns a particular controller pointer.
   DeviceEntry* GetDeviceEntryForController(
       const VideoCaptureController* controller) const;
 
   bool IsOnDeviceThread() const;
 
-  // Queries the Names of the devices in the system; the formats supported by
-  // the new devices are also queried, and consolidated with the copy of the
-  // local device info cache passed. The consolidated list of devices and
-  // supported formats is returned.
-  DeviceInfos GetAvailableDevicesInfoOnDeviceThread(
+  // Consolidates the cached devices list with the list of currently connected
+  // devices in the system |names_snapshot|. Retrieves the supported formats of
+  // the new devices and sends the new cache to OnDevicesInfoEnumerated().
+  void ConsolidateDevicesInfoOnDeviceThread(
+      base::Callback<void(const DeviceInfos&)> on_devices_enumerated_callback,
       MediaStreamType stream_type,
-      const DeviceInfos& old_device_info_cache);
+      const DeviceInfos& old_device_info_cache,
+      media::VideoCaptureDevice::Names& names_snapshot);

[tommi (sloooow) - chröme, 2014/05/30 12:37:51]

const
(or if it is meant to be writable, pass by pointer)

[mcasas, 2014/05/30 14:08:50]

Made it const& and used inside a local copy for
modifications. I think it's clearer that way, 
otherwise it permeates to the the caller
that ConsolidateDevicesInfoOnDeviceThread() is 
going to manipulate/modify/destroy the Names.

 
-  // Create and Start a new VideoCaptureDevice, storing the result in
+  // Creates and Starts a new VideoCaptureDevice, storing the result in
   // |entry->video_capture_device|. Ownership of |client| passes to
   // the device.
   void DoStartDeviceOnDeviceThread(
       media::VideoCaptureSessionId session_id,
       DeviceEntry* entry,
       const media::VideoCaptureParams& params,
       scoped_ptr<media::VideoCaptureDevice::Client> client);
 
-  // Stop and destroy the VideoCaptureDevice held in
+  // Stops and destroys the VideoCaptureDevice held in
   // |entry->video_capture_device|.
   void DoStopDeviceOnDeviceThread(DeviceEntry* entry);
 
   DeviceInfo* FindDeviceInfoById(const std::string& id,
                                  DeviceInfos& device_vector);
 
   void SetDesktopCaptureWindowIdOnDeviceThread(DeviceEntry* entry,
                                                gfx::NativeViewId window_id);
 
   void SaveDesktopCaptureWindowIdOnDeviceThread(
@@ skipping 40 matching lines @@
   };
   typedef std::set<DeviceEntry*> DeviceEntries;
   DeviceEntries devices_;
 
   // Device creation factory injected on construction from MediaStreamManager or
   // from the test harness.
   scoped_ptr<media::VideoCaptureDeviceFactory> video_capture_device_factory_;
 
   // Local cache of the enumerated video capture devices' names and capture
   // supported formats. A snapshot of the current devices and their capabilities
-  // is composed in GetAvailableDevicesInfoOnDeviceThread() --coming
-  // from EnumerateDevices()--, and this snapshot is used to update this list in
-  // OnDevicesInfoEnumerated(). GetDeviceSupportedFormats() will
+  // is composed in VideoCaptureDeviceFactory::EnumerateDeviceNames() and
+  // ConsolidateDevicesInfoOnDeviceThread(), and this snapshot is used to update
+  // this list in OnDevicesInfoEnumerated(). GetDeviceSupportedFormats() will
   // use this list if the device is not started, otherwise it will retrieve the
   // active device capture format from the VideoCaptureController associated.
   DeviceInfos devices_info_cache_;
 
   // Accessed on the device thread only.
   std::map<media::VideoCaptureSessionId, gfx::NativeViewId>
       notification_window_ids_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoCaptureManager);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_VIDEO_CAPTURE_MANAGER_H_