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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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