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 AudioNode_h 26 #define AudioNode_h 27 28 #include <wtf/OwnPtr.h> 29 #include <wtf/PassOwnPtr.h> 30 #include <wtf/RefPtr.h> 31 #include <wtf/Vector.h> 32 33 #define DEBUG_AUDIONODE_REFERENCES 0 34 35 namespace WebCore { 36 37 class AudioContext; 38 class AudioNodeInput; 39 class AudioNodeOutput; 40 41 // An AudioNode is the basic building block for handling audio within an AudioContext. 42 // It may be an audio source, an intermediate processing module, or an audio destination. 43 // Each AudioNode can have inputs and/or outputs. An AudioSourceNode has no inputs and a single output. 44 // An AudioDestinationNode has one input and no outputs and represents the final destination to the audio hardware. 45 // Most processing nodes such as filters will have one input and one output, although multiple inputs and outputs are possible. 46 47 class AudioNode { 48 public: 49 enum { ProcessingSizeInFrames = 128 }; 50 51 AudioNode(AudioContext*, double sampleRate); 52 virtual ~AudioNode(); 53 54 AudioContext* context() { return m_context.get(); } 55 56 enum NodeType { 57 NodeTypeUnknown, 58 NodeTypeDestination, 59 NodeTypeAudioBufferSource, 60 NodeTypeJavaScript, 61 NodeTypeLowPass2Filter, 62 NodeTypeHighPass2Filter, 63 NodeTypePanner, 64 NodeTypeConvolver, 65 NodeTypeDelay, 66 NodeTypeGain, 67 NodeTypeChannelSplitter, 68 NodeTypeChannelMerger, 69 NodeTypeAnalyser, 70 NodeTypeEnd 71 }; 72 73 NodeType type() const { return m_type; } 74 void setType(NodeType); 75 76 // We handle our own ref-counting because of the threading issues and subtle nature of 77 // how AudioNodes can continue processing (playing one-shot sound) after there are no more 78 // JavaScript references to the object. 79 enum RefType { RefTypeNormal, RefTypeConnection, RefTypeDisabled }; 80 81 // Can be called from main thread or context's audio thread. 82 void ref(RefType refType = RefTypeNormal); 83 void deref(RefType refType = RefTypeNormal); 84 85 // Can be called from main thread or context's audio thread. It must be called while the context's graph lock is held. 86 void finishDeref(RefType refType); 87 88 // The AudioNodeInput(s) (if any) will already have their input data available when process() is called. 89 // Subclasses will take this input data and put the results in the AudioBus(s) of its AudioNodeOutput(s) (if any). 90 // Called from context's audio thread. 91 virtual void process(size_t framesToProcess) = 0; 92 93 // Resets DSP processing state (clears delay lines, filter memory, etc.) 94 // Called from context's audio thread. 95 virtual void reset() = 0; 96 97 // No significant resources should be allocated until initialize() is called. 98 // Processing may not occur until a node is initialized. 99 virtual void initialize(); 100 virtual void uninitialize(); 101 102 bool isInitialized() const { return m_isInitialized; } 103 void lazyInitialize(); 104 105 unsigned numberOfInputs() const { return m_inputs.size(); } 106 unsigned numberOfOutputs() const { return m_outputs.size(); } 107 108 AudioNodeInput* input(unsigned); 109 AudioNodeOutput* output(unsigned); 110 111 // connect() / disconnect() return true on success. 112 // Called from main thread by corresponding JavaScript methods. 113 bool connect(AudioNode* destination, unsigned outputIndex = 0, unsigned inputIndex = 0); 114 bool disconnect(unsigned outputIndex = 0); 115 116 double sampleRate() const { return m_sampleRate; } 117 118 // processIfNecessary() is called by our output(s) when the rendering graph needs this AudioNode to process. 119 // This method ensures that the AudioNode will only process once per rendering time quantum even if it's called repeatedly. 120 // This handles the case of "fanout" where an output is connected to multiple AudioNode inputs. 121 // Called from context's audio thread. 122 void processIfNecessary(size_t framesToProcess); 123 124 // Called when a new connection has been made to one of our inputs or the connection number of channels has changed. 125 // This potentially gives us enough information to perform a lazy initialization or, if necessary, a re-initialization. 126 // Called from main thread. 127 virtual void checkNumberOfChannelsForInput(AudioNodeInput*) { } 128 129 #if DEBUG_AUDIONODE_REFERENCES 130 static void printNodeCounts(); 131 #endif 132 133 bool isMarkedForDeletion() const { return m_isMarkedForDeletion; } 134 135 protected: 136 // Inputs and outputs must be created before the AudioNode is initialized. 137 void addInput(PassOwnPtr<AudioNodeInput>); 138 void addOutput(PassOwnPtr<AudioNodeOutput>); 139 140 // Called by processIfNecessary() to cause all parts of the rendering graph connected to us to process. 141 // Each rendering quantum, the audio data for each of the AudioNode's inputs will be available after this method is called. 142 // Called from context's audio thread. 143 virtual void pullInputs(size_t framesToProcess); 144 145 private: 146 volatile bool m_isInitialized; 147 NodeType m_type; 148 RefPtr<AudioContext> m_context; 149 double m_sampleRate; 150 Vector<OwnPtr<AudioNodeInput> > m_inputs; 151 Vector<OwnPtr<AudioNodeOutput> > m_outputs; 152 153 double m_lastProcessingTime; 154 155 // Ref-counting 156 volatile int m_normalRefCount; 157 volatile int m_connectionRefCount; 158 volatile int m_disabledRefCount; 159 160 bool m_isMarkedForDeletion; 161 bool m_isDisabled; 162 163 #if DEBUG_AUDIONODE_REFERENCES 164 static bool s_isNodeCountInitialized; 165 static int s_nodeCount[NodeTypeEnd]; 166 #endif 167 }; 168 169 } // namespace WebCore 170 171 #endif // AudioNode_h 172
