1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 // VideoCaptureImpl represents a capture device in renderer process. It provides 6 // interfaces for clients to Start/Stop capture. It also communicates to clients 7 // when buffer is ready, state of capture device is changed. 8 9 // VideoCaptureImpl is also a delegate of VideoCaptureMessageFilter which relays 10 // operation of a capture device to the browser process and receives responses 11 // from browser process. 12 13 // The media::VideoCapture and VideoCaptureMessageFilter::Delegate are 14 // asynchronous interfaces, which means callers can call those interfaces 15 // from any threads without worrying about thread safety. 16 // The |capture_message_loop_proxy_| is the working thread of VideoCaptureImpl. 17 // All non-const members are accessed only on that working thread. 18 // 19 // Implementation note: tasks are posted bound to Unretained(this) to both the 20 // I/O and Capture threads and this is safe (even though the I/O thread is 21 // scoped to the renderer process and the capture_message_loop_proxy_ thread is 22 // scoped to the VideoCaptureImplManager) because VideoCaptureImplManager only 23 // triggers deletion of its VideoCaptureImpl's by calling DeInit which detours 24 // through the capture & I/O threads, so as long as nobody posts tasks after the 25 // DeInit() call is made, it is guaranteed none of these Unretained posted tasks 26 // will dangle after the delete goes through. The "as long as" is guaranteed by 27 // clients of VideoCaptureImplManager not using devices after they've 28 // RemoveDevice'd them. 29 30 #ifndef CONTENT_RENDERER_MEDIA_VIDEO_CAPTURE_IMPL_H_ 31 #define CONTENT_RENDERER_MEDIA_VIDEO_CAPTURE_IMPL_H_ 32 33 #include <list> 34 #include <map> 35 36 #include "base/memory/weak_ptr.h" 37 #include "content/common/content_export.h" 38 #include "content/common/media/video_capture.h" 39 #include "content/renderer/media/video_capture_message_filter.h" 40 #include "media/video/capture/video_capture.h" 41 #include "media/video/capture/video_capture_types.h" 42 43 namespace base { 44 class MessageLoopProxy; 45 } 46 47 namespace content { 48 49 class CONTENT_EXPORT VideoCaptureImpl 50 : public media::VideoCapture, public VideoCaptureMessageFilter::Delegate { 51 public: 52 // media::VideoCapture interface. 53 virtual void StartCapture( 54 media::VideoCapture::EventHandler* handler, 55 const media::VideoCaptureParams& params) OVERRIDE; 56 virtual void StopCapture(media::VideoCapture::EventHandler* handler) OVERRIDE; 57 virtual bool CaptureStarted() OVERRIDE; 58 virtual int CaptureFrameRate() OVERRIDE; 59 60 // VideoCaptureMessageFilter::Delegate interface. 61 virtual void OnBufferCreated(base::SharedMemoryHandle handle, 62 int length, 63 int buffer_id) OVERRIDE; 64 virtual void OnBufferDestroyed(int buffer_id) OVERRIDE; 65 virtual void OnBufferReceived( 66 int buffer_id, 67 base::Time timestamp, 68 const media::VideoCaptureFormat& format) OVERRIDE; 69 virtual void OnStateChanged(VideoCaptureState state) OVERRIDE; 70 virtual void OnDelegateAdded(int32 device_id) OVERRIDE; 71 72 // Stop/resume delivering video frames to clients, based on flag |suspend|. 73 virtual void SuspendCapture(bool suspend); 74 75 private: 76 friend class VideoCaptureImplManager; 77 friend class VideoCaptureImplTest; 78 friend class MockVideoCaptureImpl; 79 80 class ClientBuffer; 81 typedef std::map<media::VideoCapture::EventHandler*, 82 media::VideoCaptureParams> ClientInfo; 83 84 VideoCaptureImpl(media::VideoCaptureSessionId session_id, 85 base::MessageLoopProxy* capture_message_loop_proxy, 86 VideoCaptureMessageFilter* filter); 87 virtual ~VideoCaptureImpl(); 88 89 void DoStartCaptureOnCaptureThread( 90 media::VideoCapture::EventHandler* handler, 91 const media::VideoCaptureParams& params); 92 void DoStopCaptureOnCaptureThread(media::VideoCapture::EventHandler* handler); 93 void DoBufferCreatedOnCaptureThread(base::SharedMemoryHandle handle, 94 int length, 95 int buffer_id); 96 void DoBufferDestroyedOnCaptureThread(int buffer_id); 97 void DoBufferReceivedOnCaptureThread( 98 int buffer_id, 99 base::Time timestamp, 100 const media::VideoCaptureFormat& format); 101 void DoClientBufferFinishedOnCaptureThread( 102 int buffer_id, 103 const scoped_refptr<ClientBuffer>& buffer); 104 void DoStateChangedOnCaptureThread(VideoCaptureState state); 105 void DoDelegateAddedOnCaptureThread(int32 device_id); 106 107 void DoSuspendCaptureOnCaptureThread(bool suspend); 108 109 void Init(); 110 void DeInit(base::Closure task); 111 void DoDeInitOnCaptureThread(base::Closure task); 112 void StopDevice(); 113 void RestartCapture(); 114 void StartCaptureInternal(); 115 void AddDelegateOnIOThread(); 116 void RemoveDelegateOnIOThread(base::Closure task); 117 virtual void Send(IPC::Message* message); 118 119 // Helpers. 120 bool RemoveClient(media::VideoCapture::EventHandler* handler, 121 ClientInfo* clients); 122 123 const scoped_refptr<VideoCaptureMessageFilter> message_filter_; 124 const scoped_refptr<base::MessageLoopProxy> capture_message_loop_proxy_; 125 const scoped_refptr<base::MessageLoopProxy> io_message_loop_proxy_; 126 int device_id_; 127 const int session_id_; 128 129 // Buffers available for sending to the client. 130 typedef std::map<int32, scoped_refptr<ClientBuffer> > ClientBufferMap; 131 ClientBufferMap client_buffers_; 132 133 ClientInfo clients_; 134 ClientInfo clients_pending_on_filter_; 135 ClientInfo clients_pending_on_restart_; 136 137 // Member params_ represents the video format requested by the 138 // client to this class via DoStartCaptureOnCaptureThread. 139 media::VideoCaptureParams params_; 140 141 // The device's video capture format sent from browser process side. 142 media::VideoCaptureFormat last_frame_format_; 143 144 bool suspended_; 145 VideoCaptureState state_; 146 147 // WeakPtrFactory pointing back to |this| object, for use with 148 // media::VideoFrames constructed in OnBufferReceived() from buffers cached 149 // in |client_buffers_|. 150 base::WeakPtrFactory<VideoCaptureImpl> weak_this_factory_; 151 152 DISALLOW_COPY_AND_ASSIGN(VideoCaptureImpl); 153 }; 154 155 } // namespace content 156 157 #endif // CONTENT_RENDERER_MEDIA_VIDEO_CAPTURE_IMPL_H_ 158
