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// Copyright (C) 2023 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#include "qaudiostatemachine_p.h"
#include "qaudiosystem_p.h"
#include <qpointer.h>
#include <qdebug.h>
QT_BEGIN_NAMESPACE
using Notifier = QAudioStateMachine::Notifier;
using namespace AudioStateMachineUtils;
struct QAudioStateMachine::Synchronizer {
QMutex m_mutex;
QWaitCondition m_condition;
template <typename Changer>
void changeState(Changer&& changer) {
{
QMutexLocker locker(&m_mutex);
changer();
}
m_condition.notify_all();
}
void waitForOperationFinished(std::atomic<RawState>& state)
{
QMutexLocker locker(&m_mutex);
while (isWaitingState(state))
m_condition.wait(&m_mutex);
}
void waitForDrained(std::atomic<RawState>& state, std::chrono::milliseconds timeout) {
QMutexLocker locker(&m_mutex);
if (isDrainingState(state))
m_condition.wait(&m_mutex, timeout.count());
}
};
QAudioStateMachine::QAudioStateMachine(QAudioStateChangeNotifier ¬ifier, bool synchronize) :
m_notifier(¬ifier),
m_sychronizer(synchronize ? std::make_unique<Synchronizer>() : nullptr)
{
}
QAudioStateMachine::~QAudioStateMachine() = default;
QAudio::State QAudioStateMachine::state() const
{
return toAudioState(m_state);
}
QAudio::Error QAudioStateMachine::error() const
{
return m_error;
}
Notifier QAudioStateMachine::changeState(std::pair<RawState, uint32_t> prevStatesSet,
RawState newState, QAudio::Error error, bool shouldDrain)
{
auto checkState = [flags = prevStatesSet.second](RawState state) {
return (flags >> state) & 1;
};
if (!m_sychronizer) {
RawState prevState = prevStatesSet.first;
const auto exchanged = multipleCompareExchange(
m_state, prevState, newState, checkState);
if (Q_LIKELY(exchanged))
return { this, newState, prevState, error };
return {};
}
while (true) {
RawState prevState = prevStatesSet.first;
const auto newWaitingState = newState | (shouldDrain ? WaitingFlags : InProgressFlag);
const auto exchanged = multipleCompareExchange(
m_state, prevState, newWaitingState, [checkState](RawState state) {
return !isWaitingState(state) && checkState(state);
});
if (Q_LIKELY(exchanged))
return { this, newState, prevState, error };
if (!isWaitingState(prevState))
return {};
if (!checkState(fromWaitingState(prevState)))
return {};
m_sychronizer->waitForOperationFinished(m_state);
}
}
Notifier QAudioStateMachine::stop(QAudio::Error error, bool shouldDrain, bool forceUpdateError)
{
auto result = changeState(
makeStatesSet(QAudio::ActiveState, QAudio::IdleState, QAudio::SuspendedState),
QAudio::StoppedState, error, shouldDrain);
if (!result && forceUpdateError)
setError(error);
return result;
}
Notifier QAudioStateMachine::start(bool active)
{
return changeState(makeStatesSet(QAudio::StoppedState),
active ? QAudio::ActiveState : QAudio::IdleState);
}
void QAudioStateMachine::waitForDrained(std::chrono::milliseconds timeout)
{
if (m_sychronizer)
m_sychronizer->waitForDrained(m_state, timeout);
}
void QAudioStateMachine::onDrained()
{
if (m_sychronizer)
m_sychronizer->changeState([this]() { m_state &= ~DrainingFlag; });
}
bool QAudioStateMachine::isDraining() const
{
return isDrainingState(m_state);
}
bool QAudioStateMachine::isActiveOrIdle() const {
const auto state = this->state();
return state == QAudio::ActiveState || state == QAudio::IdleState;
}
std::pair<bool, bool> QAudioStateMachine::getDrainedAndStopped() const
{
const RawState state = m_state;
return { !isDrainingState(state), toAudioState(state) == QAudio::StoppedState };
}
Notifier QAudioStateMachine::suspend()
{
// Due to the current documentation, we set QAudio::NoError.
// TBD: leave the previous error should be more reasonable (IgnoreError)
const auto error = QAudio::NoError;
auto result = changeState(makeStatesSet(QAudio::ActiveState, QAudio::IdleState),
QAudio::SuspendedState, error);
if (result)
m_suspendedInState = result.prevState();
return result;
}
Notifier QAudioStateMachine::resume()
{
// Due to the current documentation, we set QAudio::NoError.
// TBD: leave the previous error should be more reasonable (IgnoreError)
const auto error = QAudio::NoError;
return changeState(makeStatesSet(QAudio::SuspendedState), m_suspendedInState, error);
}
Notifier QAudioStateMachine::activateFromIdle()
{
return changeState(makeStatesSet(QAudio::IdleState), QAudio::ActiveState);
}
Notifier QAudioStateMachine::updateActiveOrIdle(bool isActive, QAudio::Error error)
{
const auto state = isActive ? QAudio::ActiveState : QAudio::IdleState;
return changeState(makeStatesSet(QAudio::ActiveState, QAudio::IdleState), state, error);
}
void QAudioStateMachine::setError(QAudio::Error error)
{
if (m_error.exchange(error) != error && m_notifier)
emit m_notifier->errorChanged(error);
}
Notifier QAudioStateMachine::forceSetState(QAudio::State state, QAudio::Error error)
{
return changeState(makeStatesSet(QAudio::ActiveState, QAudio::IdleState, QAudio::SuspendedState,
QAudio::StoppedState),
state, error);
}
void QAudioStateMachine::reset(RawState state, RawState prevState, QAudio::Error error)
{
Q_ASSERT(!isWaitingState(state));
if (!m_sychronizer && m_state != state)
return;
const auto isErrorChanged = m_error.exchange(error) != error;
if (m_sychronizer)
m_sychronizer->changeState([&](){ m_state = state; });
auto notifier = m_notifier;
if (prevState != state && notifier)
emit notifier->stateChanged(toAudioState(state));
// check the notifier in case the object was deleted in
if (isErrorChanged && notifier)
emit notifier->errorChanged(error);
}
QT_END_NAMESPACE
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