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25 #ifndef AudioSummingJunction_h
26 #define AudioSummingJunction_h
28 #include "platform/audio/AudioBus.h"
29 #include "platform/heap/Handle.h"
30 #include "wtf/HashSet.h"
31 #include "wtf/Vector.h"
36 class AudioNodeOutput;
38 // An AudioSummingJunction represents a point where zero, one, or more AudioNodeOutputs connect.
40 class AudioSummingJunction {
42 explicit AudioSummingJunction(AudioContext*);
43 virtual ~AudioSummingJunction();
45 // Can be called from any thread.
46 AudioContext* context() { return m_context.get(); }
48 // This must be called whenever we modify m_outputs.
49 void changedOutputs();
51 // This copies m_outputs to m_renderingOutputs. Please see comments for these lists below.
52 // 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.
53 void updateRenderingState();
55 // Rendering code accesses its version of the current connections here.
56 unsigned numberOfRenderingConnections() const { return m_renderingOutputs.size(); }
57 AudioNodeOutput* renderingOutput(unsigned i) { return m_renderingOutputs[i]; }
58 bool isConnected() const { return numberOfRenderingConnections() > 0; }
60 virtual bool canUpdateState() = 0;
61 virtual void didUpdate() = 0;
64 RefPtrWillBePersistent<AudioContext> m_context;
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;
70 // m_renderingOutputs is a copy of m_outputs which will never be modified during the graph rendering on the audio thread.
71 // This is the list which is used by the rendering code.
72 // Whenever m_outputs is modified, the context is told so it can later update m_renderingOutputs from m_outputs at a safe time.
73 // Most of the time, m_renderingOutputs is identical to m_outputs.
74 Vector<AudioNodeOutput*> m_renderingOutputs;
76 // m_renderingStateNeedUpdating keeps track if m_outputs is modified.
77 bool m_renderingStateNeedUpdating;
80 } // namespace WebCore
82 #endif // AudioSummingJunction_h