OfflineAudioContext.cpp   [plain text]

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#include "config.h"

#if ENABLE(WEB_AUDIO)

#include "OfflineAudioContext.h"

#include "AudioBuffer.h"
#include "AudioUtilities.h"
#include "Document.h"
#include "JSAudioBuffer.h"
#include <wtf/IsoMallocInlines.h>

namespace WebCore {

WTF_MAKE_ISO_ALLOCATED_IMPL(OfflineAudioContext);

inline OfflineAudioContext::OfflineAudioContext(Document& document, AudioBuffer* renderTarget)
    : BaseAudioContext(document, renderTarget)
{
}

ExceptionOr<Ref<OfflineAudioContext>> OfflineAudioContext::create(ScriptExecutionContext& context, unsigned numberOfChannels, size_t length, float sampleRate)
{
    // FIXME: Add support for workers.
    if (!is<Document>(context))
        return Exception { NotSupportedError };
    if (!numberOfChannels || numberOfChannels > 10)
        return Exception { SyntaxError, "Number of channels is not in range"_s };
    if (!length)
        return Exception { SyntaxError, "length cannot be 0"_s };
    if (!isSupportedSampleRate(sampleRate))
        return Exception { SyntaxError, "sampleRate is not in range"_s };
    auto renderTarget = AudioBuffer::create(numberOfChannels, length, sampleRate);
    if (!renderTarget)
        return Exception { SyntaxError, "Unable to create AudioBuffer"_s };

    auto audioContext = adoptRef(*new OfflineAudioContext(downcast<Document>(context), renderTarget.get()));
    audioContext->suspendIfNeeded();
    return audioContext;
}

ExceptionOr<Ref<OfflineAudioContext>> OfflineAudioContext::create(ScriptExecutionContext& context, const OfflineAudioContextOptions& contextOptions)
{
    return create(context, contextOptions.numberOfChannels, contextOptions.length, contextOptions.sampleRate);
}

void OfflineAudioContext::uninitialize()
{
    BaseAudioContext::uninitialize();

    Vector<RefPtr<DeferredPromise>> promisesToReject;

    {
        AutoLocker locker(*this);
        promisesToReject.reserveInitialCapacity(m_suspendRequests.size());
        for (auto& promise : m_suspendRequests.values())
            promisesToReject.uncheckedAppend(promise);
        m_suspendRequests.clear();
    }

    if (m_pendingOfflineRenderingPromise)
        promisesToReject.append(std::exchange(m_pendingOfflineRenderingPromise, nullptr));

    for (auto& promise : promisesToReject)
        promise->reject(Exception { InvalidStateError, "Context is going away"_s });
}

void OfflineAudioContext::startOfflineRendering(Ref<DeferredPromise>&& promise)
{
    if (isStopped()) {
        promise->reject(Exception { InvalidStateError, "Context is stopped"_s });
        return;
    }

    if (m_didStartOfflineRendering) {
        promise->reject(Exception { InvalidStateError, "Rendering was already started"_s });
        return;
    }

    if (!willBeginPlayback()) {
        promise->reject(Exception { InvalidStateError, "Refusing to start rendering for security reasons" });
        return;
    }

    lazyInitialize();

    auto result = destination()->startRendering();
    if (result.hasException()) {
        promise->reject(result.releaseException());
        return;
    }

    makePendingActivity();
    m_pendingOfflineRenderingPromise = WTFMove(promise);
    m_didStartOfflineRendering = true;
    setState(State::Running);
}

void OfflineAudioContext::suspendOfflineRendering(double suspendTime, Ref<DeferredPromise>&& promise)
{
    if (isStopped()) {
        promise->reject(Exception { InvalidStateError, "Context is stopped"_s });
        return;
    }

    if (suspendTime < 0) {
        promise->reject(Exception { InvalidStateError, "suspendTime cannot be negative"_s });
        return;
    }

    double totalRenderDuration = renderTarget()->length() / sampleRate();
    if (totalRenderDuration <= suspendTime) {
        promise->reject(Exception { InvalidStateError, "suspendTime cannot be greater than total rendering duration"_s });
        return;
    }

    size_t frame = AudioUtilities::timeToSampleFrame(suspendTime, sampleRate());
    frame = OfflineAudioDestinationNode::renderQuantumSize * ((frame + OfflineAudioDestinationNode::renderQuantumSize - 1) / OfflineAudioDestinationNode::renderQuantumSize);
    if (frame < currentSampleFrame()) {
        promise->reject(Exception { InvalidStateError, "Suspension frame is earlier than current frame"_s });
        return;
    }

    AutoLocker locker(*this);
    auto addResult = m_suspendRequests.add(frame, promise.ptr());
    if (!addResult.isNewEntry) {
        promise->reject(Exception { InvalidStateError, "There is already a pending suspend request at this frame"_s });
        return;
    }
}

void OfflineAudioContext::resumeOfflineRendering(Ref<DeferredPromise>&& promise)
{
    if (!m_didStartOfflineRendering) {
        promise->reject(Exception { InvalidStateError, "Cannot resume an offline audio context that has not started"_s });
        return;
    }
    if (isClosed()) {
        promise->reject(Exception { InvalidStateError, "Cannot resume an offline audio context that is closed"_s });
        return;
    }
    if (state() == AudioContextState::Running) {
        promise->resolve();
        return;
    }
    ASSERT(state() == AudioContextState::Suspended);

    auto result = destination()->startRendering();
    if (result.hasException()) {
        promise->reject(result.releaseException());
        return;
    }

    makePendingActivity();
    setState(State::Running);
    promise->resolve();
}

bool OfflineAudioContext::shouldSuspend()
{
    ASSERT(!isMainThread());
    // Note that OfflineAutoLocker uses lock() instead of tryLock(). We usually avoid blocking the AudioThread
    // on lock() but we don't have a choice here since the suspension need to be exact.
    OfflineAutoLocker locker(*this);
    return m_suspendRequests.contains(currentSampleFrame());
}

void OfflineAudioContext::didSuspendRendering(size_t frame)
{
    BaseAudioContext::didSuspendRendering(frame);

    RefPtr<DeferredPromise> promise;
    {
        AutoLocker locker(*this);
        promise = m_suspendRequests.take(frame);
    }
    ASSERT(promise);
    if (promise)
        promise->resolve();
}

void OfflineAudioContext::didFinishOfflineRendering(ExceptionOr<Ref<AudioBuffer>>&& result)
{
    m_didStartOfflineRendering = false;

    if (!m_pendingOfflineRenderingPromise)
        return;

    auto promise = std::exchange(m_pendingOfflineRenderingPromise, nullptr);
    if (result.hasException()) {
        promise->reject(result.releaseException());
        return;
    }
    promise->resolve<IDLInterface<AudioBuffer>>(result.releaseReturnValue());
}

unsigned OfflineAudioContext::length() const
{
    return renderTarget()->length();
}

void OfflineAudioContext::offlineLock(bool& mustReleaseLock)
{
    ASSERT(!isMainThread());
    lockInternal(mustReleaseLock);
}

} // namespace WebCore

#endif // ENABLE(WEB_AUDIO)