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 "AudioNodeInput.h"
30
31#include "AudioContext.h"
32#include "AudioNode.h"
33#include "AudioNodeOutput.h"
34#include <algorithm>
35
36namespace WebCore {
37
38AudioNodeInput::AudioNodeInput(AudioNode* node)
39    : AudioSummingJunction(node->context())
40    , m_node(node)
41{
42    // Set to mono by default.
43    m_internalSummingBus = AudioBus::create(1, AudioNode::ProcessingSizeInFrames);
44}
45
46void AudioNodeInput::connect(AudioNodeOutput* output)
47{
48    ASSERT(context()->isGraphOwner());
49
50    ASSERT(output && node());
51    if (!output || !node())
52        return;
53
54    // Check if we're already connected to this output.
55    if (!m_outputs.add(output).isNewEntry)
56        return;
57
58    output->addInput(this);
59    changedOutputs();
60
61    // Sombody has just connected to us, so count it as a reference.
62    node()->ref(AudioNode::RefTypeConnection);
63}
64
65void AudioNodeInput::disconnect(AudioNodeOutput* output)
66{
67    ASSERT(context()->isGraphOwner());
68
69    ASSERT(output && node());
70    if (!output || !node())
71        return;
72
73    // First try to disconnect from "active" connections.
74    if (m_outputs.remove(output)) {
75        changedOutputs();
76        output->removeInput(this);
77        node()->deref(AudioNode::RefTypeConnection); // Note: it's important to return immediately after all deref() calls since the node may be deleted.
78        return;
79    }
80
81    // Otherwise, try to disconnect from disabled connections.
82    if (m_disabledOutputs.remove(output)) {
83        output->removeInput(this);
84        node()->deref(AudioNode::RefTypeConnection); // Note: it's important to return immediately after all deref() calls since the node may be deleted.
85        return;
86    }
87
88    ASSERT_NOT_REACHED();
89}
90
91void AudioNodeInput::disable(AudioNodeOutput* output)
92{
93    ASSERT(context()->isGraphOwner());
94
95    ASSERT(output && node());
96    if (!output || !node())
97        return;
98
99    ASSERT(m_outputs.contains(output));
100
101    m_disabledOutputs.add(output);
102    m_outputs.remove(output);
103    changedOutputs();
104
105    // Propagate disabled state to outputs.
106    node()->disableOutputsIfNecessary();
107}
108
109void AudioNodeInput::enable(AudioNodeOutput* output)
110{
111    ASSERT(context()->isGraphOwner());
112
113    ASSERT(output && node());
114    if (!output || !node())
115        return;
116
117    ASSERT(m_disabledOutputs.contains(output));
118
119    // Move output from disabled list to active list.
120    m_outputs.add(output);
121    m_disabledOutputs.remove(output);
122    changedOutputs();
123
124    // Propagate enabled state to outputs.
125    node()->enableOutputsIfNecessary();
126}
127
128void AudioNodeInput::didUpdate()
129{
130    node()->checkNumberOfChannelsForInput(this);
131}
132
133void AudioNodeInput::updateInternalBus()
134{
135    ASSERT(context()->isAudioThread() && context()->isGraphOwner());
136
137    unsigned numberOfInputChannels = numberOfChannels();
138
139    if (numberOfInputChannels == m_internalSummingBus->numberOfChannels())
140        return;
141
142    m_internalSummingBus = AudioBus::create(numberOfInputChannels, AudioNode::ProcessingSizeInFrames);
143}
144
145unsigned AudioNodeInput::numberOfChannels() const
146{
147    AudioNode::ChannelCountMode mode = node()->internalChannelCountMode();
148    if (mode == AudioNode::Explicit)
149        return node()->channelCount();
150
151    // Find the number of channels of the connection with the largest number of channels.
152    unsigned maxChannels = 1; // one channel is the minimum allowed
153
154    for (HashSet<AudioNodeOutput*>::iterator i = m_outputs.begin(); i != m_outputs.end(); ++i) {
155        AudioNodeOutput* output = *i;
156        // Use output()->numberOfChannels() instead of output->bus()->numberOfChannels(),
157        // because the calling of AudioNodeOutput::bus() is not safe here.
158        maxChannels = std::max(maxChannels, output->numberOfChannels());
159    }
160
161    if (mode == AudioNode::ClampedMax)
162        maxChannels = std::min(maxChannels, static_cast<unsigned>(node()->channelCount()));
163
164    return maxChannels;
165}
166
167AudioBus* AudioNodeInput::bus()
168{
169    ASSERT(context()->isAudioThread());
170
171    // Handle single connection specially to allow for in-place processing.
172    if (numberOfRenderingConnections() == 1 && node()->internalChannelCountMode() == AudioNode::Max)
173        return renderingOutput(0)->bus();
174
175    // Multiple connections case or complex ChannelCountMode (or no connections).
176    return internalSummingBus();
177}
178
179AudioBus* AudioNodeInput::internalSummingBus()
180{
181    ASSERT(context()->isAudioThread());
182
183    return m_internalSummingBus.get();
184}
185
186void AudioNodeInput::sumAllConnections(AudioBus* summingBus, size_t framesToProcess)
187{
188    ASSERT(context()->isAudioThread());
189
190    // We shouldn't be calling this method if there's only one connection, since it's less efficient.
191    ASSERT(numberOfRenderingConnections() > 1 || node()->internalChannelCountMode() != AudioNode::Max);
192
193    ASSERT(summingBus);
194    if (!summingBus)
195        return;
196
197    summingBus->zero();
198
199    AudioBus::ChannelInterpretation interpretation = node()->internalChannelInterpretation();
200
201    for (unsigned i = 0; i < numberOfRenderingConnections(); ++i) {
202        AudioNodeOutput* output = renderingOutput(i);
203        ASSERT(output);
204
205        // Render audio from this output.
206        AudioBus* connectionBus = output->pull(0, framesToProcess);
207
208        // Sum, with unity-gain.
209        summingBus->sumFrom(*connectionBus, interpretation);
210    }
211}
212
213AudioBus* AudioNodeInput::pull(AudioBus* inPlaceBus, size_t framesToProcess)
214{
215    ASSERT(context()->isAudioThread());
216
217    // Handle single connection case.
218    if (numberOfRenderingConnections() == 1 && node()->internalChannelCountMode() == AudioNode::Max) {
219        // The output will optimize processing using inPlaceBus if it's able.
220        AudioNodeOutput* output = this->renderingOutput(0);
221        return output->pull(inPlaceBus, framesToProcess);
222    }
223
224    AudioBus* internalSummingBus = this->internalSummingBus();
225
226    if (!numberOfRenderingConnections()) {
227        // At least, generate silence if we're not connected to anything.
228        // FIXME: if we wanted to get fancy, we could propagate a 'silent hint' here to optimize the downstream graph processing.
229        internalSummingBus->zero();
230        return internalSummingBus;
231    }
232
233    // Handle multiple connections case.
234    sumAllConnections(internalSummingBus, framesToProcess);
235
236    return internalSummingBus;
237}
238
239} // namespace WebCore
240
241#endif // ENABLE(WEB_AUDIO)
242