Update SingleApplication to upstream master

2025-12-17 20:50:34 +01:00 · 2021-02-28 18:05:18 +01:00
parent 28cd389695
commit 7c3bde9118
18 changed files with 923 additions and 628 deletions
--- a/SingleApplication/singleapplication.cpp
+++ b/SingleApplication/singleapplication.cpp
@@ -1,6 +1,6 @@
 // The MIT License (MIT)
 //
-// Copyright (c) Itay Grudev 2015 - 2018
+// Copyright (c) Itay Grudev 2015 - 2020
 //
 // Permission is hereby granted, free of charge, to any person obtaining a copy
 // of this software and associated documentation files (the "Software"), to deal
@@ -20,176 +20,255 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 // THE SOFTWARE.

-#include <QtCore/QTime>
-#include <QtCore/QThread>
-#include <QtCore/QDateTime>
+#include <QtCore/QElapsedTimer>
 #include <QtCore/QByteArray>
 #include <QtCore/QSharedMemory>
-#if QT_VERSION < QT_VERSION_CHECK(5, 10, 0)	// ### Qt 6: remove
-#else
-#if TODO_LIST
-#pragma message("@TODO remove code for QT 5.10 or later")
-#endif
-#include <QRandomGenerator>
-#endif
+
 #include "singleapplication.h"
 #include "singleapplication_p.h"

 /**
-	@brief Constructor. Checks and fires up LocalServer or closes the program
-	if another instance already exists
-	@param argc
-	@param argv
-	@param {bool} allowSecondaryInstances
-*/
-SingleApplication::SingleApplication( int &argc, char *argv[], bool allowSecondary, Options options, int timeout )
-	: app_t( argc, argv ), d_ptr( new SingleApplicationPrivate( this ) )
+ * @brief Constructor. Checks and fires up LocalServer or closes the program
+ * if another instance already exists
+ * @param argc
+ * @param argv
+ * @param allowSecondary Whether to enable secondary instance support
+ * @param options Optional flags to toggle specific behaviour
+ * @param timeout Maximum time blocking functions are allowed during app load
+ */
+SingleApplication::SingleApplication( int &argc, char *argv[], bool allowSecondary, Options options, int timeout, const QString &userData )
+    : app_t( argc, argv ), d_ptr( new SingleApplicationPrivate( this ) )
 {
-	Q_D(SingleApplication);
+    Q_D( SingleApplication );

 #if defined(Q_OS_ANDROID) || defined(Q_OS_IOS)
-	// On Android and iOS since the library is not supported fallback to
-	// standard QApplication behaviour by simply returning at this point.
-	qWarning() << "SingleApplication is not supported on Android and iOS systems.";
-	return;
+    // On Android and iOS since the library is not supported fallback to
+    // standard QApplication behaviour by simply returning at this point.
+    qWarning() << "SingleApplication is not supported on Android and iOS systems.";
+    return;
 #endif

-	// Store the current mode of the program
-	d->options = options;
+    // Store the current mode of the program
+    d->options = options;

-	// Generating an application ID used for identifying the shared memory
-	// block and QLocalServer
-	d->genBlockServerName();
+    // Add any unique user data
+    if ( ! userData.isEmpty() )
+        d->addAppData( userData );
+
+    // Generating an application ID used for identifying the shared memory
+    // block and QLocalServer
+    d->genBlockServerName();
+
+    // To mitigate QSharedMemory issues with large amount of processes
+    // attempting to attach at the same time
+    SingleApplicationPrivate::randomSleep();

 #ifdef Q_OS_UNIX
-	// By explicitly attaching it and then deleting it we make sure that the
-	// memory is deleted even after the process has crashed on Unix.
-	d->memory = new QSharedMemory( d->blockServerName );
-	d->memory->attach();
-	delete d->memory;
+    // By explicitly attaching it and then deleting it we make sure that the
+    // memory is deleted even after the process has crashed on Unix.
+    d->memory = new QSharedMemory( d->blockServerName );
+    d->memory->attach();
+    delete d->memory;
 #endif
-	// Guarantee thread safe behaviour with a shared memory block.
-	d->memory = new QSharedMemory( d->blockServerName );
+    // Guarantee thread safe behaviour with a shared memory block.
+    d->memory = new QSharedMemory( d->blockServerName );

-	// Create a shared memory block
-	if( d->memory->create( sizeof( InstancesInfo ) ) ) {
-		// Initialize the shared memory block
-		d->memory->lock();
-		d->initializeMemoryBlock();
-		d->memory->unlock();
-	} else {
-		// Attempt to attach to the memory segment
-		if( ! d->memory->attach() ) {
-			qCritical() << "SingleApplication: Unable to attach to shared memory block.";
-			qCritical() << d->memory->errorString();
-			delete d;
-			::exit( EXIT_FAILURE );
-		}
-	}
+    // Create a shared memory block
+    if( d->memory->create( sizeof( InstancesInfo ) )){
+        // Initialize the shared memory block
+        if( ! d->memory->lock() ){
+          qCritical() << "SingleApplication: Unable to lock memory block after create.";
+          abortSafely();
+        }
+        d->initializeMemoryBlock();
+    } else {
+        if( d->memory->error() == QSharedMemory::AlreadyExists ){
+          // Attempt to attach to the memory segment
+          if( ! d->memory->attach() ){
+              qCritical() << "SingleApplication: Unable to attach to shared memory block.";
+              abortSafely();
+          }
+          if( ! d->memory->lock() ){
+            qCritical() << "SingleApplication: Unable to lock memory block after attach.";
+            abortSafely();
+          }
+        } else {
+          qCritical() << "SingleApplication: Unable to create block.";
+          abortSafely();
+        }
+    }

-	InstancesInfo* inst = static_cast<InstancesInfo*>( d->memory->data() );
-	QElapsedTimer time;
-	time.start();
+    auto *inst = static_cast<InstancesInfo*>( d->memory->data() );
+    QElapsedTimer time;
+    time.start();

-	// Make sure the shared memory block is initialised and in consistent state
-	while( true ) {
-		d->memory->lock();
+    // Make sure the shared memory block is initialised and in consistent state
+    while( true ){
+      // If the shared memory block's checksum is valid continue
+      if( d->blockChecksum() == inst->checksum ) break;

-		if( d->blockChecksum() == inst->checksum ) break;
+      // If more than 5s have elapsed, assume the primary instance crashed and
+      // assume it's position
+      if( time.elapsed() > 5000 ){
+          qWarning() << "SingleApplication: Shared memory block has been in an inconsistent state from more than 5s. Assuming primary instance failure.";
+          d->initializeMemoryBlock();
+      }

-		if( time.elapsed() > 5000 ) {
-			qWarning() << "SingleApplication: Shared memory block has been in an inconsistent state from more than 5s. Assuming primary instance failure.";
-			d->initializeMemoryBlock();
-		}
+      // Otherwise wait for a random period and try again. The random sleep here
+      // limits the probability of a collision between two racing apps and
+      // allows the app to initialise faster
+      if( ! d->memory->unlock() ){
+        qDebug() << "SingleApplication: Unable to unlock memory for random wait.";
+        qDebug() << d->memory->errorString();
+      }
+      SingleApplicationPrivate::randomSleep();
+      if( ! d->memory->lock() ){
+        qCritical() << "SingleApplication: Unable to lock memory after random wait.";
+        abortSafely();
+      }
+    }

-		d->memory->unlock();
+    if( inst->primary == false ){
+        d->startPrimary();
+        if( ! d->memory->unlock() ){
+          qDebug() << "SingleApplication: Unable to unlock memory after primary start.";
+          qDebug() << d->memory->errorString();
+        }
+        return;
+    }

-		// Random sleep here limits the probability of a collision between two racing apps
-#if QT_VERSION < QT_VERSION_CHECK(5, 10, 0)	// ### Qt 6: remove
-		qsrand( QDateTime::currentMSecsSinceEpoch() % std::numeric_limits<uint>::max() );
-		QThread::sleep( 8 + static_cast <unsigned long>( static_cast <float>( qrand() ) / RAND_MAX * 10 ) );
-#else
-#if TODO_LIST
-#pragma message("@TODO remove code for QT 5.10 or later")
-#endif
-		quint32 value = QRandomGenerator::global()->generate();
-		QThread::sleep(8 + static_cast<unsigned long>(value / RAND_MAX * 10));
-#endif
-	}
+    // Check if another instance can be started
+    if( allowSecondary ){
+        d->startSecondary();
+        if( d->options & Mode::SecondaryNotification ){
+            d->connectToPrimary( timeout, SingleApplicationPrivate::SecondaryInstance );
+        }
+        if( ! d->memory->unlock() ){
+          qDebug() << "SingleApplication: Unable to unlock memory after secondary start.";
+          qDebug() << d->memory->errorString();
+        }
+        return;
+    }

-	if( inst->primary == false) {
-		d->startPrimary();
-		d->memory->unlock();
-		return;
-	}
+    if( ! d->memory->unlock() ){
+      qDebug() << "SingleApplication: Unable to unlock memory at end of execution.";
+      qDebug() << d->memory->errorString();
+    }

-	// Check if another instance can be started
-	if( allowSecondary ) {
-		inst->secondary += 1;
-		inst->checksum = d->blockChecksum();
-		d->instanceNumber = inst->secondary;
-		d->startSecondary();
-		if( d->options & Mode::SecondaryNotification ) {
-			d->connectToPrimary( timeout, SingleApplicationPrivate::SecondaryInstance );
-		}
-		d->memory->unlock();
-		return;
-	}
+    d->connectToPrimary( timeout, SingleApplicationPrivate::NewInstance );

-	d->memory->unlock();
+    delete d;

-	d->connectToPrimary( timeout, SingleApplicationPrivate::NewInstance );
+    ::exit( EXIT_SUCCESS );
+}

-	delete d;
-
-	::exit( EXIT_SUCCESS );
+SingleApplication::~SingleApplication()
+{
+    Q_D( SingleApplication );
+    delete d;
 }

 /**
-	@brief Destructor
-*/
-SingleApplication::~SingleApplication()
+ * Checks if the current application instance is primary.
+ * @return Returns true if the instance is primary, false otherwise.
+ */
+bool SingleApplication::isPrimary() const
 {
-	Q_D(SingleApplication);
-	delete d;
+    Q_D( const SingleApplication );
+    return d->server != nullptr;
 }

-bool SingleApplication::isPrimary()
+/**
+ * Checks if the current application instance is secondary.
+ * @return Returns true if the instance is secondary, false otherwise.
+ */
+bool SingleApplication::isSecondary() const
 {
-	Q_D(SingleApplication);
-	return d->server != nullptr;
+    Q_D( const SingleApplication );
+    return d->server == nullptr;
 }

-bool SingleApplication::isSecondary()
+/**
+ * Allows you to identify an instance by returning unique consecutive instance
+ * ids. It is reset when the first (primary) instance of your app starts and
+ * only incremented afterwards.
+ * @return Returns a unique instance id.
+ */
+quint32 SingleApplication::instanceId() const
 {
-	Q_D(SingleApplication);
-	return d->server == nullptr;
+    Q_D( const SingleApplication );
+    return d->instanceNumber;
 }

-quint32 SingleApplication::instanceId()
+/**
+ * Returns the OS PID (Process Identifier) of the process running the primary
+ * instance. Especially useful when SingleApplication is coupled with OS.
+ * specific APIs.
+ * @return Returns the primary instance PID.
+ */
+qint64 SingleApplication::primaryPid() const
 {
-	Q_D(SingleApplication);
-	return d->instanceNumber;
+    Q_D( const SingleApplication );
+    return d->primaryPid();
 }

-qint64 SingleApplication::primaryPid()
+/**
+ * Returns the username the primary instance is running as.
+ * @return Returns the username the primary instance is running as.
+ */
+QString SingleApplication::primaryUser() const
 {
-	Q_D(SingleApplication);
-	return d->primaryPid();
+    Q_D( const SingleApplication );
+    return d->primaryUser();
 }

-bool SingleApplication::sendMessage( QByteArray message, int timeout )
+/**
+ * Returns the username the current instance is running as.
+ * @return Returns the username the current instance is running as.
+ */
+QString SingleApplication::currentUser() const
 {
-	Q_D(SingleApplication);
-
-	// Nobody to connect to
-	if( isPrimary() ) return false;
-
-	// Make sure the socket is connected
-	d->connectToPrimary( timeout,  SingleApplicationPrivate::Reconnect );
-
-	d->socket->write( message );
-	bool dataWritten = d->socket->waitForBytesWritten( timeout );
-	d->socket->flush();
-	return dataWritten;
+    return SingleApplicationPrivate::getUsername();
+}
+
+/**
+ * Sends message to the Primary Instance.
+ * @param message The message to send.
+ * @param timeout the maximum timeout in milliseconds for blocking functions.
+ * @return true if the message was sent successfuly, false otherwise.
+ */
+bool SingleApplication::sendMessage( const QByteArray &message, int timeout )
+{
+    Q_D( SingleApplication );
+
+    // Nobody to connect to
+    if( isPrimary() ) return false;
+
+    // Make sure the socket is connected
+    if( ! d->connectToPrimary( timeout,  SingleApplicationPrivate::Reconnect ) )
+      return false;
+
+    d->socket->write( message );
+    bool dataWritten = d->socket->waitForBytesWritten( timeout );
+    d->socket->flush();
+    return dataWritten;
+}
+
+/**
+ * Cleans up the shared memory block and exits with a failure.
+ * This function halts program execution.
+ */
+void SingleApplication::abortSafely()
+{
+    Q_D( SingleApplication );
+
+    qCritical() << "SingleApplication: " << d->memory->error() << d->memory->errorString();
+    delete d;
+    ::exit( EXIT_FAILURE );
+}
+
+QStringList SingleApplication::userData() const
+{
+    Q_D( const SingleApplication );
+    return d->appData();
 }