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 AudioDestinationNode_h
26#define AudioDestinationNode_h
27
28#include "core/platform/audio/AudioBus.h"
29#include "core/platform/audio/AudioIOCallback.h"
30#include "core/platform/audio/AudioSourceProvider.h"
31#include "modules/webaudio/AudioBuffer.h"
32#include "modules/webaudio/AudioNode.h"
33
34namespace WebCore {
35
36class AudioBus;
37class AudioContext;
38
39class AudioDestinationNode : public AudioNode, public AudioIOCallback {
40public:
41    AudioDestinationNode(AudioContext*, float sampleRate);
42    virtual ~AudioDestinationNode();
43
44    // AudioNode
45    virtual void process(size_t) { }; // we're pulled by hardware so this is never called
46    virtual void reset() { m_currentSampleFrame = 0; };
47
48    // The audio hardware calls render() to get the next render quantum of audio into destinationBus.
49    // It will optionally give us local/live audio input in sourceBus (if it's not 0).
50    virtual void render(AudioBus* sourceBus, AudioBus* destinationBus, size_t numberOfFrames);
51
52    size_t currentSampleFrame() const { return m_currentSampleFrame; }
53    double currentTime() const { return currentSampleFrame() / static_cast<double>(sampleRate()); }
54
55    virtual unsigned long maxChannelCount() const { return 0; }
56
57    // Enable local/live input for the specified device.
58    virtual void enableInput(const String& inputDeviceId) = 0;
59
60    virtual void startRendering() = 0;
61
62    AudioSourceProvider* localAudioInputProvider() { return &m_localAudioInputProvider; }
63
64protected:
65    // LocalAudioInputProvider allows us to expose an AudioSourceProvider for local/live audio input.
66    // If there is local/live audio input, we call set() with the audio input data every render quantum.
67    class LocalAudioInputProvider : public AudioSourceProvider {
68    public:
69        LocalAudioInputProvider()
70            : m_sourceBus(AudioBus::create(2, AudioNode::ProcessingSizeInFrames)) // FIXME: handle non-stereo local input.
71        {
72        }
73
74        void set(AudioBus* bus)
75        {
76            if (bus)
77                m_sourceBus->copyFrom(*bus);
78        }
79
80        // AudioSourceProvider.
81        virtual void provideInput(AudioBus* destinationBus, size_t numberOfFrames)
82        {
83            bool isGood = destinationBus && destinationBus->length() == numberOfFrames && m_sourceBus->length() == numberOfFrames;
84            ASSERT(isGood);
85            if (isGood)
86                destinationBus->copyFrom(*m_sourceBus);
87        }
88
89    private:
90        RefPtr<AudioBus> m_sourceBus;
91    };
92
93    virtual double tailTime() const OVERRIDE { return 0; }
94    virtual double latencyTime() const OVERRIDE { return 0; }
95
96    // Counts the number of sample-frames processed by the destination.
97    size_t m_currentSampleFrame;
98
99    LocalAudioInputProvider m_localAudioInputProvider;
100};
101
102} // namespace WebCore
103
104#endif // AudioDestinationNode_h
105