3d34f66292
R=alexeypa@chromium.org, wez@chromium.org Review URL: https://webrtc-codereview.appspot.com/1586005 git-svn-id: http://webrtc.googlecode.com/svn/trunk@4175 4adac7df-926f-26a2-2b94-8c16560cd09d
75 lines
2.6 KiB
C++
75 lines
2.6 KiB
C++
/*
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* Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef WEBRTC_MODULES_DESKTOP_CAPTURE_SCREEN_CAPTURE_FRAME_QUEUE_H_
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#define WEBRTC_MODULES_DESKTOP_CAPTURE_SCREEN_CAPTURE_FRAME_QUEUE_H_
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#include "webrtc/modules/desktop_capture/shared_desktop_frame.h"
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#include "webrtc/system_wrappers/interface/scoped_ptr.h"
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#include "webrtc/typedefs.h"
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namespace webrtc {
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class DesktopFrame;
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} // namespace webrtc
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namespace webrtc {
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// Represents a queue of reusable video frames. Provides access to the 'current'
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// frame - the frame that the caller is working with at the moment, and to the
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// 'previous' frame - the predecessor of the current frame swapped by
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// MoveToNextFrame() call, if any.
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//
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// The caller is expected to (re)allocate frames if current_frame() returns
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// NULL. The caller can mark all frames in the queue for reallocation (when,
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// say, frame dimensions change). The queue records which frames need updating
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// which the caller can query.
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//
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// Frame consumer is expected to never hold more than kQueueLength frames
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// created by this function and it should release the earliest one before trying
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// to capture a new frame (i.e. before MoveToNextFrame() is called).
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class ScreenCaptureFrameQueue {
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public:
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ScreenCaptureFrameQueue();
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~ScreenCaptureFrameQueue();
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// Moves to the next frame in the queue, moving the 'current' frame to become
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// the 'previous' one.
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void MoveToNextFrame();
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// Replaces the current frame with a new one allocated by the caller. The
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// existing frame (if any) is destroyed. Takes ownership of |frame|.
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void ReplaceCurrentFrame(DesktopFrame* frame);
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// Marks all frames obsolete and resets the previous frame pointer. No
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// frames are freed though as the caller can still access them.
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void Reset();
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SharedDesktopFrame* current_frame() const {
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return frames_[current_].get();
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}
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SharedDesktopFrame* previous_frame() const {
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return frames_[(current_ + kQueueLength - 1) % kQueueLength].get();
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}
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private:
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// Index of the current frame.
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int current_;
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static const int kQueueLength = 2;
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scoped_ptr<SharedDesktopFrame> frames_[kQueueLength];
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DISALLOW_COPY_AND_ASSIGN(ScreenCaptureFrameQueue);
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};
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} // namespace webrtc
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#endif // WEBRTC_MODULES_DESKTOP_CAPTURE_SCREEN_CAPTURE_FRAME_QUEUE_H_
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