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 | #pragma once |
26 | |
27 | #include "AudioBus.h" |
28 | #include <wtf/HashSet.h> |
29 | #include <wtf/Vector.h> |
30 | |
31 | namespace WebCore { |
32 | |
33 | class AudioContext; |
34 | class AudioNodeOutput; |
35 | |
36 | // An AudioSummingJunction represents a point where zero, one, or more AudioNodeOutputs connect. |
37 | |
38 | class AudioSummingJunction { |
39 | public: |
40 | explicit AudioSummingJunction(AudioContext&); |
41 | virtual ~AudioSummingJunction(); |
42 | |
43 | // Can be called from any thread. |
44 | AudioContext& context() { return m_context.get(); } |
45 | |
46 | // This must be called whenever we modify m_outputs. |
47 | void changedOutputs(); |
48 | |
49 | // This copies m_outputs to m_renderingOutputs. Please see comments for these lists below. |
50 | // 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. |
51 | void updateRenderingState(); |
52 | |
53 | // Rendering code accesses its version of the current connections here. |
54 | unsigned numberOfRenderingConnections() const { return m_renderingOutputs.size(); } |
55 | AudioNodeOutput* renderingOutput(unsigned i) { return m_renderingOutputs[i]; } |
56 | const AudioNodeOutput* renderingOutput(unsigned i) const { return m_renderingOutputs[i]; } |
57 | bool isConnected() const { return numberOfRenderingConnections() > 0; } |
58 | |
59 | virtual bool canUpdateState() = 0; |
60 | virtual void didUpdate() = 0; |
61 | |
62 | protected: |
63 | Ref<AudioContext> m_context; |
64 | |
65 | // m_outputs contains the AudioNodeOutputs representing current connections which are not disabled. |
66 | // The rendering code should never use this directly, but instead uses m_renderingOutputs. |
67 | HashSet<AudioNodeOutput*> m_outputs; |
68 | |
69 | // numberOfConnections() should never be called from the audio rendering thread. |
70 | // Instead numberOfRenderingConnections() and renderingOutput() should be used. |
71 | unsigned numberOfConnections() const { return m_outputs.size(); } |
72 | |
73 | // m_renderingOutputs is a copy of m_outputs which will never be modified during the graph rendering on the audio thread. |
74 | // This is the list which is used by the rendering code. |
75 | // Whenever m_outputs is modified, the context is told so it can later update m_renderingOutputs from m_outputs at a safe time. |
76 | // Most of the time, m_renderingOutputs is identical to m_outputs. |
77 | Vector<AudioNodeOutput*> m_renderingOutputs; |
78 | |
79 | // m_renderingStateNeedUpdating keeps track if m_outputs is modified. |
80 | bool m_renderingStateNeedUpdating; |
81 | }; |
82 | |
83 | } // namespace WebCore |
84 | |