1 /* 2 * Copyright (C) 2012, Google Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY 14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 15 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 16 * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY 17 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 18 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 19 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON 20 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 22 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 23 */ 24 25 #ifndef AudioSummingJunction_h 26 #define AudioSummingJunction_h 27 28 #include "core/platform/audio/AudioBus.h" 29 #include "wtf/HashSet.h" 30 #include "wtf/Vector.h" 31 32 namespace WebCore { 33 34 class AudioContext; 35 class AudioNodeOutput; 36 37 // An AudioSummingJunction represents a point where zero, one, or more AudioNodeOutputs connect. 38 39 class AudioSummingJunction { 40 public: 41 explicit AudioSummingJunction(AudioContext*); 42 virtual ~AudioSummingJunction(); 43 44 // Can be called from any thread. 45 AudioContext* context() { return m_context.get(); } 46 47 // This must be called whenever we modify m_outputs. 48 void changedOutputs(); 49 50 // This copies m_outputs to m_renderingOutputs. Please see comments for these lists below. 51 // This must be called when we own the context's graph lock in the audio thread at the very start or end of the render quantum. 52 void updateRenderingState(); 53 54 // Rendering code accesses its version of the current connections here. 55 unsigned numberOfRenderingConnections() const { return m_renderingOutputs.size(); } 56 AudioNodeOutput* renderingOutput(unsigned i) { return m_renderingOutputs[i]; } 57 const AudioNodeOutput* renderingOutput(unsigned i) const { return m_renderingOutputs[i]; } 58 bool isConnected() const { return numberOfRenderingConnections() > 0; } 59 60 virtual bool canUpdateState() = 0; 61 virtual void didUpdate() = 0; 62 63 protected: 64 RefPtr<AudioContext> m_context; 65 66 // m_outputs contains the AudioNodeOutputs representing current connections which are not disabled. 67 // The rendering code should never use this directly, but instead uses m_renderingOutputs. 68 HashSet<AudioNodeOutput*> m_outputs; 69 70 // numberOfConnections() should never be called from the audio rendering thread. 71 // Instead numberOfRenderingConnections() and renderingOutput() should be used. 72 unsigned numberOfConnections() const { return m_outputs.size(); } 73 74 // m_renderingOutputs is a copy of m_outputs which will never be modified during the graph rendering on the audio thread. 75 // This is the list which is used by the rendering code. 76 // Whenever m_outputs is modified, the context is told so it can later update m_renderingOutputs from m_outputs at a safe time. 77 // Most of the time, m_renderingOutputs is identical to m_outputs. 78 Vector<AudioNodeOutput*> m_renderingOutputs; 79 80 // m_renderingStateNeedUpdating keeps track if m_outputs is modified. 81 bool m_renderingStateNeedUpdating; 82 }; 83 84 } // namespace WebCore 85 86 #endif // AudioSummingJunction_h 87
