1 /* 2 * Copyright (C) 2010, 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 AudioNodeOutput_h 26 #define AudioNodeOutput_h 27 28 #include "AudioBus.h" 29 #include "AudioNode.h" 30 #include <wtf/HashSet.h> 31 #include <wtf/OwnPtr.h> 32 #include <wtf/Vector.h> 33 34 namespace WebCore { 35 36 class AudioContext; 37 class AudioNodeInput; 38 39 // AudioNodeOutput represents a single output for an AudioNode. 40 // It may be connected to one or more AudioNodeInputs. 41 42 class AudioNodeOutput { 43 public: 44 // It's OK to pass 0 for numberOfChannels in which case setNumberOfChannels() must be called later on. 45 AudioNodeOutput(AudioNode*, unsigned numberOfChannels); 46 47 // Can be called from any thread. 48 AudioNode* node() const { return m_node; } 49 AudioContext* context() { return m_node->context(); } 50 51 // Causes our AudioNode to process if it hasn't already for this render quantum. 52 // It returns the bus containing the processed audio for this output, returning inPlaceBus if in-place processing was possible. 53 // Called from context's audio thread. 54 AudioBus* pull(AudioBus* inPlaceBus, size_t framesToProcess); 55 56 // bus() will contain the rendered audio after pull() is called for each rendering time quantum. 57 // Called from context's audio thread. 58 AudioBus* bus() const; 59 60 // fanOutCount() is the number of AudioNodeInputs that we're connected to. 61 // This function should not be called in audio thread rendering code, instead renderingFanOutCount() should be used. 62 // It must be called with the context's graph lock. 63 unsigned fanOutCount(); 64 65 // renderingFanOutCount() is the number of AudioNodeInputs that we're connected to during rendering. 66 // Unlike fanOutCount() it will not change during the course of a render quantum. 67 unsigned renderingFanOutCount() const; 68 69 // It must be called with the context's graph lock. 70 void disconnectAllInputs(); 71 72 void setNumberOfChannels(unsigned); 73 unsigned numberOfChannels() const { return m_numberOfChannels; } 74 bool isChannelCountKnown() const { return numberOfChannels() > 0; } 75 76 // Disable/Enable happens when there are still JavaScript references to a node, but it has otherwise "finished" its work. 77 // For example, when a note has finished playing. It is kept around, because it may be played again at a later time. 78 // They must be called with the context's graph lock. 79 void disable(); 80 void enable(); 81 82 // updateRenderingState() is called in the audio thread at the start or end of the render quantum to handle any recent changes to the graph state. 83 // It must be called with the context's graph lock. 84 void updateRenderingState(); 85 86 private: 87 AudioNode* m_node; 88 89 friend class AudioNodeInput; 90 91 // These are called from AudioNodeInput. 92 // They must be called with the context's graph lock. 93 void addInput(AudioNodeInput*); 94 void removeInput(AudioNodeInput*); 95 96 // setInternalBus() sets m_internalOutputBus appropriately for the number of channels. 97 // It is called in the constructor or in the audio thread with the context's graph lock. 98 void setInternalBus(); 99 100 // Announce to any nodes we're connected to that we changed our channel count for its input. 101 // It must be called in the audio thread with the context's graph lock. 102 void propagateChannelCount(); 103 104 // updateNumberOfChannels() is called in the audio thread at the start or end of the render quantum to pick up channel changes. 105 // It must be called with the context's graph lock. 106 void updateNumberOfChannels(); 107 108 // m_numberOfChannels will only be changed in the audio thread. 109 // The main thread sets m_desiredNumberOfChannels which will later get picked up in the audio thread in updateNumberOfChannels(). 110 unsigned m_numberOfChannels; 111 unsigned m_desiredNumberOfChannels; 112 113 // m_internalOutputBus will point to either m_monoInternalBus or m_stereoInternalBus. 114 // It must only be changed in the audio thread (or constructor). 115 AudioBus* m_internalOutputBus; 116 OwnPtr<AudioBus> m_monoInternalBus; 117 OwnPtr<AudioBus> m_stereoInternalBus; 118 119 // m_actualDestinationBus is set in pull() and will either point to one of our internal busses or to the in-place bus. 120 // It must only be changed in the audio thread (or constructor). 121 AudioBus* m_actualDestinationBus; 122 123 HashSet<AudioNodeInput*> m_inputs; 124 typedef HashSet<AudioNodeInput*>::iterator InputsIterator; 125 bool m_isEnabled; 126 127 // For the purposes of rendering, keeps track of the number of inputs we're connected to. 128 // This value should only be changed at the very start or end of the rendering quantum. 129 unsigned m_renderingFanOutCount; 130 }; 131 132 } // namespace WebCore 133 134 #endif // AudioNodeOutput_h 135
