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| 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 #ifndef REMOTING_HOST_VIDEO_FRAME_QUEUE_H_ | |
| 6 #define REMOTING_HOST_VIDEO_FRAME_QUEUE_H_ | |
| 7 | |
| 8 #include "base/compiler_specific.h" | |
| 9 #include "base/memory/scoped_ptr.h" | |
| 10 | |
| 11 namespace remoting { | |
| 12 | |
| 13 class VideoFrame; | |
| 14 | |
| 15 // Represents a queue of reusable video frames. Provides access to the 'current' | |
| 16 // frame - the frame that the caller is working with at the moment, and to | |
| 17 // the 'previous' frame - the predecessor of the current frame swapped by | |
| 18 // DoneWithCurrentFrame() call, if any. | |
| 19 // | |
| 20 // The caller is expected to (re)allocate frames if current_frame_needs_update() | |
| 21 // is set. The caller can mark all frames in the queue for reallocation (when, | |
| 22 // say, frame dimensions change). The queue records which frames need updating | |
| 23 // which the caller can query. | |
| 24 class VideoFrameQueue { | |
| 25 public: | |
| 26 VideoFrameQueue(); | |
| 27 ~VideoFrameQueue(); | |
| 28 | |
| 29 // Moves to the next frame in the queue, moving the 'current' frame to become | |
| 30 // the 'previous' one. | |
| 31 void DoneWithCurrentFrame(); | |
| 32 | |
| 33 // Replaces the current frame with a new one allocated by the caller. | |
| 34 // The existing frame (if any) is destroyed. | |
| 35 void ReplaceCurrentFrame(scoped_ptr<VideoFrame> frame); | |
| 36 | |
| 37 // Marks all frames obsolete and resets the previous frame pointer. No | |
| 38 // frames are freed though as the caller can still access them. | |
| 39 void SetAllFramesNeedUpdate(); | |
| 40 | |
| 41 VideoFrame* current_frame() const { | |
| 42 return frames_[current_].get(); | |
| 43 } | |
| 44 | |
| 45 bool current_frame_needs_update() const { | |
| 46 return !current_frame() || needs_update_[current_]; | |
| 47 } | |
| 48 | |
| 49 VideoFrame* previous_frame() const { return previous_; } | |
| 50 | |
| 51 private: | |
| 52 // Index of the current frame. | |
| 53 int current_; | |
| 54 | |
| 55 static const int kQueueLength = 2; | |
| 56 scoped_ptr<VideoFrame> frames_[kQueueLength]; | |
| 57 | |
| 58 // True if the corresponding frame needs to be re-allocated. | |
| 59 bool needs_update_[kQueueLength]; | |
| 60 | |
| 61 // Points to the previous frame if any. | |
| 62 VideoFrame* previous_; | |
| 63 | |
| 64 DISALLOW_COPY_AND_ASSIGN(VideoFrameQueue); | |
| 65 }; | |
| 66 | |
| 67 } // namespace remoting | |
| 68 | |
| 69 #endif // REMOTING_HOST_VIDEO_FRAME_QUEUE_H_ | |
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