Rename StateChangeGuard -> Notifier

The patch is a part of QAudioStateMachine prettification.
QAudioStateMachine::Notifier is going to do only signal notifications.

Change-Id: Ic76d1af6ec5be704a3c10597c2ac4240841ce4a4
Reviewed-by: Artem Dyomin <artem.dyomin@qt.io>
(cherry picked from commit 775497cbe8caf8c1da16000d7198bd81533129ae)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
(cherry picked from commit 55517575ec573a87d91254fba1de54c7cb69e0b9)

5 files changed, 57 insertions, 60 deletions

diff --git a/src/multimedia/audio/qaudiostatemachine.cpp b/src/multimedia/audio/qaudiostatemachine.cpp
index 5a6de2673..8f501fc11 100644
--- a/src/multimedia/audio/qaudiostatemachine.cpp
+++ b/src/multimedia/audio/qaudiostatemachine.cpp
@@ -8,7 +8,7 @@
 
 QT_BEGIN_NAMESPACE
 
-using Guard = QAudioStateMachine::StateChangeGuard;
+using Notifier = QAudioStateMachine::Notifier;
 using RawState = QAudioStateMachine::RawState;
 
 namespace {
@@ -104,8 +104,8 @@ QAudio::Error QAudioStateMachine::error() const
     return m_error;
 }
 
-Guard QAudioStateMachine::changeState(std::pair<RawState, uint32_t> prevStatesSet,
-                                      RawState newState, QAudio::Error error, bool shouldDrain)
+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;
@@ -145,7 +145,7 @@ Guard QAudioStateMachine::changeState(std::pair<RawState, uint32_t> prevStatesSe
     }
 }
 
-Guard QAudioStateMachine::stop(QAudio::Error error, bool shouldDrain, bool forceUpdateError)
+Notifier QAudioStateMachine::stop(QAudio::Error error, bool shouldDrain, bool forceUpdateError)
 {
     auto result = changeState(
             makeStatesSet(QAudio::ActiveState, QAudio::IdleState, QAudio::SuspendedState),
@@ -157,7 +157,7 @@ Guard QAudioStateMachine::stop(QAudio::Error error, bool shouldDrain, bool force
     return result;
 }
 
-Guard QAudioStateMachine::start(bool active)
+Notifier QAudioStateMachine::start(bool active)
 {
     return changeState(makeStatesSet(QAudio::StoppedState),
                        active ? QAudio::ActiveState : QAudio::IdleState);
@@ -191,7 +191,7 @@ std::pair<bool, bool> QAudioStateMachine::getDrainedAndStopped() const
     return { !isDrainingState(state), toAudioState(state) == QAudio::StoppedState };
 }
 
-Guard QAudioStateMachine::suspend()
+Notifier QAudioStateMachine::suspend()
 {
     // Due to the current documentation, we set QAudio::NoError.
     // TBD: leave the previous error should be more reasonable (IgnoreError)
@@ -205,7 +205,7 @@ Guard QAudioStateMachine::suspend()
     return result;
 }
 
-Guard QAudioStateMachine::resume()
+Notifier QAudioStateMachine::resume()
 {
     // Due to the current documentation, we set QAudio::NoError.
     // TBD: leave the previous error should be more reasonable (IgnoreError)
@@ -213,12 +213,12 @@ Guard QAudioStateMachine::resume()
     return changeState(makeStatesSet(QAudio::SuspendedState), m_suspendedInState, error);
 }
 
-Guard QAudioStateMachine::activateFromIdle()
+Notifier QAudioStateMachine::activateFromIdle()
 {
     return changeState(makeStatesSet(QAudio::IdleState), QAudio::ActiveState);
 }
 
-Guard QAudioStateMachine::updateActiveOrIdle(bool isActive, QAudio::Error error)
+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);
@@ -230,7 +230,7 @@ void QAudioStateMachine::setError(QAudio::Error error)
         emit m_notifier->errorChanged(error);
 }
 
-Guard QAudioStateMachine::forceSetState(QAudio::State state, QAudio::Error error)
+Notifier QAudioStateMachine::forceSetState(QAudio::State state, QAudio::Error error)
 {
     return changeState(makeStatesSet(QAudio::ActiveState, QAudio::IdleState, QAudio::SuspendedState,
                                      QAudio::StoppedState),
diff --git a/src/multimedia/audio/qaudiostatemachine_p.h b/src/multimedia/audio/qaudiostatemachine_p.h
index 44ea051a2..1baee3ef4 100644
--- a/src/multimedia/audio/qaudiostatemachine_p.h
+++ b/src/multimedia/audio/qaudiostatemachine_p.h
@@ -30,9 +30,8 @@ class QAudioStateChangeNotifier;
 /* QAudioStateMachine provides an opportunity to
  * toggle QAudio::State with QAudio::Error in
  * a thread-safe manner.
- * The toggling functions return a guard,
- * which scope guaranties thread safety (if synchronization enabled)
- * and notifies about the change via
+ * The toggling functions return a notifier,
+ * which notifies about the change via
  * QAudioStateChangeNotifier::stateChanged and errorChanged.
  *
  * The state machine is supposed to be used mostly in
@@ -42,7 +41,7 @@ class Q_MULTIMEDIA_EXPORT QAudioStateMachine
 {
 public:
     using RawState = int;
-    class StateChangeGuard
+    class Notifier
     {
     public:
         void reset()
@@ -51,10 +50,10 @@ public:
                 stateMachine->reset(m_state, m_prevState, m_error);
         }
 
-        ~StateChangeGuard() { reset(); }
+        ~Notifier() { reset(); }
 
-        StateChangeGuard(const StateChangeGuard &) = delete;
-        StateChangeGuard(StateChangeGuard &&other) noexcept
+        Notifier(const Notifier &) = delete;
+        Notifier(Notifier &&other) noexcept
             : m_stateMachine(std::exchange(other.m_stateMachine, nullptr)),
               m_state(other.m_state),
               m_prevState(other.m_prevState),
@@ -69,7 +68,7 @@ public:
         // Can be added make state changing more flexible
         // but needs some investigation to ensure state change consistency
         // The method is supposed to be used for sync read/write
-        // under "guard = updateActiveOrIdle(isActive)"
+        // under "notifier = updateActiveOrIdle(isActive)"
         // void setState(QAudio::State state) { ... }
 
         bool isStateChanged() const { return m_state != m_prevState; }
@@ -77,10 +76,8 @@ public:
         QAudio::State prevState() const { return QAudio::State(m_prevState); }
 
     private:
-        StateChangeGuard(QAudioStateMachine *stateMachine = nullptr,
-                         RawState state = QAudio::StoppedState,
-                         RawState prevState = QAudio::StoppedState,
-                         QAudio::Error error = QAudio::NoError)
+        Notifier(QAudioStateMachine *stateMachine = nullptr, RawState state = QAudio::StoppedState,
+                 RawState prevState = QAudio::StoppedState, QAudio::Error error = QAudio::NoError)
             : m_stateMachine(stateMachine), m_state(state), m_prevState(prevState), m_error(error)
         {
         }
@@ -116,39 +113,39 @@ public:
     void onDrained();
 
     // Active/Idle/Suspended -> Stopped
-    StateChangeGuard stop(QAudio::Error error = QAudio::NoError, bool shouldDrain = false,
-                          bool forceUpdateError = false);
+    Notifier stop(QAudio::Error error = QAudio::NoError, bool shouldDrain = false,
+                  bool forceUpdateError = false);
 
     // Active/Idle/Suspended -> Stopped
-    StateChangeGuard stopOrUpdateError(QAudio::Error error = QAudio::NoError)
+    Notifier stopOrUpdateError(QAudio::Error error = QAudio::NoError)
     {
         return stop(error, false, true);
     }
 
     // Stopped -> Active/Idle
-    StateChangeGuard start(bool isActive = true);
+    Notifier start(bool isActive = true);
 
     // Active/Idle -> Suspended + saves the exchanged state
-    StateChangeGuard suspend();
+    Notifier suspend();
 
     // Suspended -> saved state (Active/Idle)
-    StateChangeGuard resume();
+    Notifier resume();
 
     // Idle -> Active
-    StateChangeGuard activateFromIdle();
+    Notifier activateFromIdle();
 
     // Active/Idle -> Active/Idle + updateError
-    StateChangeGuard updateActiveOrIdle(bool isActive, QAudio::Error error = QAudio::NoError);
+    Notifier updateActiveOrIdle(bool isActive, QAudio::Error error = QAudio::NoError);
 
     // Any -> Any; better use more strict methods
-    StateChangeGuard forceSetState(QAudio::State state, QAudio::Error error = QAudio::NoError);
+    Notifier forceSetState(QAudio::State state, QAudio::Error error = QAudio::NoError);
 
     // force set the error
     void setError(QAudio::Error error);
 
 private:
-    StateChangeGuard changeState(std::pair<RawState, uint32_t> prevStatesSet, RawState state,
-                                 QAudio::Error error = QAudio::NoError, bool shouldDrain = false);
+    Notifier changeState(std::pair<RawState, uint32_t> prevStatesSet, RawState state,
+                         QAudio::Error error = QAudio::NoError, bool shouldDrain = false);
 
     void reset(RawState state, RawState prevState, QAudio::Error error);
 
diff --git a/src/multimedia/darwin/qdarwinaudiosink.mm b/src/multimedia/darwin/qdarwinaudiosink.mm
index 134d779c3..e2d128483 100644
--- a/src/multimedia/darwin/qdarwinaudiosink.mm
+++ b/src/multimedia/darwin/qdarwinaudiosink.mm
@@ -271,8 +271,8 @@ void QDarwinAudioSink::stop()
     if (m_audioBuffer)
         m_audioBuffer->setFillingEnabled(false);
 
-    if (auto guard = m_stateMachine.stop(QAudio::NoError, true)) {
-        if (guard.prevState() == QAudio::ActiveState) {
+    if (auto notifier = m_stateMachine.stop(QAudio::NoError, true)) {
+        if (notifier.prevState() == QAudio::ActiveState) {
             m_stateMachine.waitForDrained(std::chrono::milliseconds(500));
 
             if (m_stateMachine.isDraining())
diff --git a/src/multimedia/pulseaudio/qpulseaudiosink.cpp b/src/multimedia/pulseaudio/qpulseaudiosink.cpp
index 5ac27d9df..612f65de6 100644
--- a/src/multimedia/pulseaudio/qpulseaudiosink.cpp
+++ b/src/multimedia/pulseaudio/qpulseaudiosink.cpp
@@ -118,10 +118,10 @@ QPulseAudioSink::QPulseAudioSink(const QByteArray &device, QObject *parent)
 
 QPulseAudioSink::~QPulseAudioSink()
 {
-    if (auto guard = m_stateMachine.stop()) {
+    if (auto notifier = m_stateMachine.stop()) {
         close();
         QSignalBlocker blocker(this);
-        guard.reset();
+        notifier.reset();
     }
 }
 
@@ -166,8 +166,8 @@ void QPulseAudioSink::start(QIODevice *device)
         return;
     }
 
-    auto guard = m_stateMachine.start();
-    Q_ASSERT(guard);
+    auto notifier = m_stateMachine.start();
+    Q_ASSERT(notifier);
 
     // ensure we only process timing infos that are up to date
     gettimeofday(&lastTimingInfo, nullptr);
@@ -191,8 +191,8 @@ QIODevice *QPulseAudioSink::start()
     if (!open())
         return nullptr;
 
-    auto guard = m_stateMachine.start(false);
-    Q_ASSERT(guard);
+    auto notifier = m_stateMachine.start(false);
+    Q_ASSERT(notifier);
 
     m_audioSource = new PulseOutputPrivate(this);
     m_audioSource->open(QIODevice::WriteOnly|QIODevice::Unbuffered);
@@ -487,7 +487,7 @@ qint64 QPulseAudioSink::write(const char *data, qint64 len)
 
 void QPulseAudioSink::stop()
 {
-    if (auto guard = m_stateMachine.stop())
+    if (auto notifier = m_stateMachine.stop())
         close();
 }
 
@@ -579,7 +579,7 @@ qint64 QPulseAudioSink::processedUSecs() const
 
 void QPulseAudioSink::resume()
 {
-    if (auto guard = m_stateMachine.resume()) {
+    if (auto notifier = m_stateMachine.resume()) {
         m_resuming = true;
 
         {
@@ -611,7 +611,7 @@ QAudioFormat QPulseAudioSink::format() const
 
 void QPulseAudioSink::suspend()
 {
-    if (auto guard = m_stateMachine.suspend()) {
+    if (auto notifier = m_stateMachine.suspend()) {
         m_tickTimer.stop();
 
         QPulseAudioEngine *pulseEngine = QPulseAudioEngine::instance();
@@ -626,7 +626,7 @@ void QPulseAudioSink::suspend()
 
 void QPulseAudioSink::reset()
 {
-    if (auto guard = m_stateMachine.stopOrUpdateError())
+    if (auto notifier = m_stateMachine.stopOrUpdateError())
         close();
 }
 
@@ -675,7 +675,7 @@ qreal QPulseAudioSink::volume() const
 
 void QPulseAudioSink::onPulseContextFailed()
 {
-    if (auto guard = m_stateMachine.stop(QAudio::FatalError))
+    if (auto notifier = m_stateMachine.stop(QAudio::FatalError))
         close();
 }
 
diff --git a/tests/auto/unit/multimedia/qaudiostatemachine/tst_qaudiostatemachine.cpp b/tests/auto/unit/multimedia/qaudiostatemachine/tst_qaudiostatemachine.cpp
index 22039f2e4..0b4375227 100644
--- a/tests/auto/unit/multimedia/qaudiostatemachine/tst_qaudiostatemachine.cpp
+++ b/tests/auto/unit/multimedia/qaudiostatemachine/tst_qaudiostatemachine.cpp
@@ -177,8 +177,8 @@ void tst_QAudioStateMachine::stop_changesState_whenStateIsNotStopped()
     QSignalSpy stateSpy(&changeNotifier, &QAudioStateChangeNotifier::stateChanged);
     QSignalSpy errorSpy(&changeNotifier, &QAudioStateChangeNotifier::errorChanged);
 
-    auto guard = stateMachine.stop();
-    QVERIFY(guard);
+    auto notifier = stateMachine.stop();
+    QVERIFY(notifier);
 
     QVERIFY(!stateMachine.isDraining());
 
@@ -188,7 +188,7 @@ void tst_QAudioStateMachine::stop_changesState_whenStateIsNotStopped()
     QCOMPARE(stateSpy.size(), 0);
     QCOMPARE(errorSpy.size(), 0);
 
-    guard.reset();
+    notifier.reset();
 
     QVERIFY(!stateMachine.isDraining());
 
@@ -286,8 +286,8 @@ void tst_QAudioStateMachine::updateActiveOrIdle_changesState_whenStateIsActiveOr
 
     const auto expectedState = active ? QAudio::ActiveState : QAudio::IdleState;
 
-    auto guard = stateMachine.updateActiveOrIdle(active, error);
-    QVERIFY(guard);
+    auto notifier = stateMachine.updateActiveOrIdle(active, error);
+    QVERIFY(notifier);
 
     QCOMPARE(stateSpy.size(), 0);
     QCOMPARE(errorSpy.size(), 0);
@@ -295,7 +295,7 @@ void tst_QAudioStateMachine::updateActiveOrIdle_changesState_whenStateIsActiveOr
     QCOMPARE(stateMachine.state(), expectedState);
     QCOMPARE(stateMachine.error(), prevError);
 
-    guard.reset();
+    notifier.reset();
 
     QCOMPARE(stateSpy.size(), expectedState == prevState ? 0 : 1);
     if (!stateSpy.empty())
@@ -316,13 +316,13 @@ void tst_QAudioStateMachine::stopWithDraining_setDrainingFlagUnderTheGuard()
 
     stateMachine.start();
 
-    auto guard = stateMachine.stop(QAudio::IOError, true);
-    QVERIFY(guard);
+    auto notifier = stateMachine.stop(QAudio::IOError, true);
+    QVERIFY(notifier);
     QVERIFY(stateMachine.isDraining());
     QCOMPARE(stateMachine.getDrainedAndStopped(), std::make_pair(false, true));
     QCOMPARE(stateMachine.state(), QAudio::StoppedState);
 
-    guard.reset();
+    notifier.reset();
 
     QVERIFY(!stateMachine.isDraining());
     QCOMPARE(stateMachine.getDrainedAndStopped(), std::make_pair(true, true));
@@ -338,8 +338,8 @@ void tst_QAudioStateMachine::onDrained_interruptsWaitingForDrained_whenCalledFro
     QSignalSpy stateSpy(&changeNotifier, &QAudioStateChangeNotifier::stateChanged);
     QSignalSpy errorSpy(&changeNotifier, &QAudioStateChangeNotifier::errorChanged);
 
-    auto guard = stateMachine.stop(QAudio::IOError, true);
-    QVERIFY(guard);
+    auto notifier = stateMachine.stop(QAudio::IOError, true);
+    QVERIFY(notifier);
     QVERIFY(stateMachine.isDraining());
     QCOMPARE(stateMachine.state(), QAudio::StoppedState);
 
@@ -366,7 +366,7 @@ void tst_QAudioStateMachine::onDrained_interruptsWaitingForDrained_whenCalledFro
     QCOMPARE(stateSpy.size(), 0);
     QCOMPARE(errorSpy.size(), 0);
 
-    guard.reset();
+    notifier.reset();
 
     QCOMPARE(stateSpy.size(), 1);
     QCOMPARE(errorSpy.size(), 1);
@@ -379,8 +379,8 @@ void tst_QAudioStateMachine::waitForDrained_waitsLimitedTime()
 
     stateMachine.start();
 
-    auto guard = stateMachine.stop(QAudio::IOError, true);
-    QVERIFY(guard);
+    auto notifier = stateMachine.stop(QAudio::IOError, true);
+    QVERIFY(notifier);
 
     QElapsedTimer elapsedTimer;
     elapsedTimer.start();