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#include "config.h"
26
27#if ENABLE(WEB_AUDIO)
28
29#include "AudioDestinationNode.h"
30
31#include "AudioBus.h"
32#include "AudioContext.h"
33#include "AudioNodeInput.h"
34#include "AudioNodeOutput.h"
35
36namespace WebCore {
37
38AudioDestinationNode::AudioDestinationNode(AudioContext* context, double sampleRate)
39    : AudioNode(context, sampleRate)
40    , m_currentTime(0.0)
41{
42    addInput(adoptPtr(new AudioNodeInput(this)));
43
44    setType(NodeTypeDestination);
45}
46
47AudioDestinationNode::~AudioDestinationNode()
48{
49    uninitialize();
50}
51
52// The audio hardware calls us back here to gets its input stream.
53void AudioDestinationNode::provideInput(AudioBus* destinationBus, size_t numberOfFrames)
54{
55    context()->setAudioThread(currentThread());
56
57    if (!context()->isRunnable()) {
58        destinationBus->zero();
59        return;
60    }
61
62    // Let the context take care of any business at the start of each render quantum.
63    context()->handlePreRenderTasks();
64
65    // This will cause the node(s) connected to us to process, which in turn will pull on their input(s),
66    // all the way backwards through the rendering graph.
67    AudioBus* renderedBus = input(0)->pull(destinationBus, numberOfFrames);
68
69    if (!renderedBus)
70        destinationBus->zero();
71    else if (renderedBus != destinationBus) {
72        // in-place processing was not possible - so copy
73        destinationBus->copyFrom(*renderedBus);
74    }
75
76    // Let the context take care of any business at the end of each render quantum.
77    context()->handlePostRenderTasks();
78
79    // Advance current time.
80    m_currentTime += numberOfFrames / sampleRate();
81}
82
83} // namespace WebCore
84
85#endif // ENABLE(WEB_AUDIO)
86