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// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "modules/webaudio/AudioContext.h"
#include "bindings/core/v8/ExceptionMessages.h"
#include "bindings/core/v8/ExceptionState.h"
#include "bindings/core/v8/ScriptPromiseResolver.h"
#include "core/dom/DOMException.h"
#include "core/dom/ExceptionCode.h"
#include "modules/webaudio/AudioBufferCallback.h"
#include "platform/audio/AudioUtilities.h"
#if DEBUG_AUDIONODE_REFERENCES
#include <stdio.h>
#endif
namespace blink {
// Don't allow more than this number of simultaneous AudioContexts
// talking to hardware.
const unsigned MaxHardwareContexts = 6;
static unsigned s_hardwareContextCount = 0;
static unsigned s_contextId = 0;
AbstractAudioContext* AudioContext::create(Document& document, ExceptionState& exceptionState)
{
ASSERT(isMainThread());
if (s_hardwareContextCount >= MaxHardwareContexts) {
exceptionState.throwDOMException(
NotSupportedError,
ExceptionMessages::indexExceedsMaximumBound(
"number of hardware contexts",
s_hardwareContextCount,
MaxHardwareContexts));
return nullptr;
}
AudioContext* audioContext = new AudioContext(document);
audioContext->suspendIfNeeded();
if (!AudioUtilities::isValidAudioBufferSampleRate(audioContext->sampleRate())) {
exceptionState.throwDOMException(
NotSupportedError,
ExceptionMessages::indexOutsideRange(
"hardware sample rate",
audioContext->sampleRate(),
AudioUtilities::minAudioBufferSampleRate(),
ExceptionMessages::InclusiveBound,
AudioUtilities::maxAudioBufferSampleRate(),
ExceptionMessages::InclusiveBound));
return audioContext;
}
// This starts the audio thread. The destination node's
// provideInput() method will now be called repeatedly to render
// audio. Each time provideInput() is called, a portion of the
// audio stream is rendered. Let's call this time period a "render
// quantum". NOTE: for now AudioContext does not need an explicit
// startRendering() call from JavaScript. We may want to consider
// requiring it for symmetry with OfflineAudioContext.
audioContext->startRendering();
++s_hardwareContextCount;
#if DEBUG_AUDIONODE_REFERENCES
fprintf(stderr, "%p: AudioContext::AudioContext(): %u #%u\n",
audioContext, audioContext->m_contextId, s_hardwareContextCount);
#endif
return audioContext;
}
AudioContext::AudioContext(Document& document)
: AbstractAudioContext(&document)
, m_contextId(s_contextId++)
{
}
AudioContext::~AudioContext()
{
#if DEBUG_AUDIONODE_REFERENCES
fprintf(stderr, "%p: AudioContext::~AudioContext(): %u\n", this, m_contextId);
#endif
}
DEFINE_TRACE(AudioContext)
{
visitor->trace(m_closeResolver);
AbstractAudioContext::trace(visitor);
}
ScriptPromise AudioContext::suspendContext(ScriptState* scriptState)
{
ASSERT(isMainThread());
AutoLocker locker(this);
ScriptPromiseResolver* resolver = ScriptPromiseResolver::create(scriptState);
ScriptPromise promise = resolver->promise();
if (contextState() == Closed) {
resolver->reject(
DOMException::create(InvalidStateError, "Cannot suspend a context that has been closed"));
} else {
// Stop rendering now.
if (destination())
stopRendering();
// Since we don't have any way of knowing when the hardware actually stops, we'll just
// resolve the promise now.
resolver->resolve();
}
return promise;
}
ScriptPromise AudioContext::resumeContext(ScriptState* scriptState)
{
ASSERT(isMainThread());
if (isContextClosed()) {
return ScriptPromise::rejectWithDOMException(
scriptState,
DOMException::create(
InvalidAccessError,
"cannot resume a closed AudioContext"));
}
ScriptPromiseResolver* resolver = ScriptPromiseResolver::create(scriptState);
ScriptPromise promise = resolver->promise();
// Restart the destination node to pull on the audio graph.
if (destination())
startRendering();
// Save the resolver which will get resolved when the destination node starts pulling on the
// graph again.
{
AutoLocker locker(this);
m_resumeResolvers.append(resolver);
}
return promise;
}
ScriptPromise AudioContext::closeContext(ScriptState* scriptState)
{
if (isContextClosed()) {
// We've already closed the context previously, but it hasn't yet been resolved, so just
// create a new promise and reject it.
return ScriptPromise::rejectWithDOMException(
scriptState,
DOMException::create(InvalidStateError,
"Cannot close a context that is being closed or has already been closed."));
}
// Save the current sample rate for any subsequent decodeAudioData calls.
setClosedContextSampleRate(sampleRate());
m_closeResolver = ScriptPromiseResolver::create(scriptState);
ScriptPromise promise = m_closeResolver->promise();
// Stop the audio context. This will stop the destination node from pulling audio anymore. And
// since we have disconnected the destination from the audio graph, and thus has no references,
// the destination node can GCed if JS has no references. uninitialize() will also resolve the Promise
// created here.
uninitialize();
return promise;
}
void AudioContext::didClose()
{
// This is specific to AudioContexts. OfflineAudioContexts
// are closed in their completion event.
setContextState(Closed);
ASSERT(s_hardwareContextCount);
--s_hardwareContextCount;
if (m_closeResolver)
m_closeResolver->resolve();
}
bool AudioContext::isContextClosed() const
{
return m_closeResolver || AbstractAudioContext::isContextClosed();
}
void AudioContext::stopRendering()
{
ASSERT(isMainThread());
ASSERT(destination());
if (contextState() == Running) {
destination()->audioDestinationHandler().stopRendering();
setContextState(Suspended);
deferredTaskHandler().clearHandlersToBeDeleted();
}
}
} // namespace blink
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