Add SingleCoreApplication

3rdparty/singleapplication/CMakeLists.txt

@@ -1,13 +1,15 @@
 cmake_minimum_required(VERSION 2.8.11)
 set(CMAKE_CXX_STANDARD 11)
-if(CMAKE_VERSION VERSION_GREATER 3.11.4)
-  add_compile_definitions(QAPPLICATION_CLASS=QApplication)
-else()
-  add_definitions(-DQAPPLICATION_CLASS=QApplication)
-endif()
+
 set(SINGLEAPP-SOURCES singleapplication.cpp singleapplication_p.cpp)
 set(SINGLEAPP-MOC-HEADERS singleapplication.h singleapplication_p.h)
 QT5_WRAP_CPP(SINGLEAPP-SOURCES-MOC ${SINGLEAPP-MOC-HEADERS})
 ADD_LIBRARY(singleapplication STATIC ${SINGLEAPP-SOURCES} ${SINGLEAPP-SOURCES-MOC})
 target_link_libraries(singleapplication Qt5::Core Qt5::Widgets Qt5::Network)
-include_directories(${CMAKE_BINARY_DIR}/src)
+
+
+set(SINGLECOREAPP-SOURCES singlecoreapplication.cpp singlecoreapplication_p.cpp)
+set(SINGLECOREAPP-MOC-HEADERS singlecoreapplication.h singlecoreapplication_p.h)
+QT5_WRAP_CPP(SINGLECOREAPP-SOURCES-MOC ${SINGLECOREAPP-MOC-HEADERS})
+ADD_LIBRARY(singlecoreapplication STATIC ${SINGLECOREAPP-SOURCES} ${SINGLECOREAPP-SOURCES-MOC})
+target_link_libraries(singlecoreapplication Qt5::Core Qt5::Widgets Qt5::Network)

3rdparty/singleapplication/singleapplication.cpp

@@ -20,6 +20,7 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 // THE SOFTWARE.
 
+#include <QApplication>
 #include <QtCore/QTime>
 #include <QtCore/QThread>
 #include <QtCore/QDateTime>

3rdparty/singleapplication/singleapplication.h

@@ -20,18 +20,13 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 // THE SOFTWARE.
 
-#ifndef SINGLE_APPLICATION_H
-#define SINGLE_APPLICATION_H
+#ifndef SINGLEAPPLICATION_H
+#define SINGLEAPPLICATION_H
 
 #include <QtCore/QtGlobal>
+#include <QApplication>
 #include <QtNetwork/QLocalSocket>
 
-#ifndef QAPPLICATION_CLASS
-  #error "QAPPLICATION_CLASS not defined."
-#endif
-
-#include QT_STRINGIFY(QAPPLICATION_CLASS)
-
 class SingleApplicationPrivate;
 
 /**
@@ -39,11 +34,11 @@ class SingleApplicationPrivate;
  * Application
  * @see QCoreApplication
  */
-class SingleApplication : public QAPPLICATION_CLASS
+class SingleApplication : public QApplication
 {
     Q_OBJECT
 
-    typedef QAPPLICATION_CLASS app_t;
+    typedef QApplication app_t;
 
 public:
     /**
@@ -132,4 +127,4 @@ private:
 
 Q_DECLARE_OPERATORS_FOR_FLAGS(SingleApplication::Options)
 
-#endif // SINGLE_APPLICATION_H
+#endif // SINGLEAPPLICATION_H

3rdparty/singleapplication/singlecoreapplication.cpp

@@ -0,0 +1,175 @@
+// The MIT License (MIT)
+//
+// Copyright (c) Itay Grudev 2015 - 2018
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+#include <QCoreApplication>
+#include <QtCore/QTime>
+#include <QtCore/QThread>
+#include <QtCore/QDateTime>
+#include <QtCore/QByteArray>
+#include <QtCore/QSharedMemory>
+
+#include "singlecoreapplication.h"
+#include "singlecoreapplication_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
+ */
+SingleCoreApplication::SingleCoreApplication( int &argc, char *argv[], bool allowSecondary, Options options, int timeout )
+    : app_t( argc, argv ), d_ptr( new SingleCoreApplicationPrivate( this ) )
+{
+    Q_D(SingleCoreApplication);
+
+    // 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();
+
+#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;
+#endif
+    // 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() << "SingleCoreApplication: Unable to attach to shared memory block.";
+            qCritical() << d->memory->errorString();
+            delete d;
+            ::exit( EXIT_FAILURE );
+        }
+    }
+
+    InstancesInfo* inst = static_cast<InstancesInfo*>( d->memory->data() );
+    QTime time;
+    time.start();
+
+    // Make sure the shared memory block is initialised and in consistent state
+    while( true ) {
+        d->memory->lock();
+
+        if( d->blockChecksum() == inst->checksum ) break;
+
+        if( time.elapsed() > 5000 ) {
+            qWarning() << "SingleCoreApplication: Shared memory block has been in an inconsistent state from more than 5s. Assuming primary instance failure.";
+            d->initializeMemoryBlock();
+        }
+
+        d->memory->unlock();
+
+        // Random sleep here limits the probability of a collision between two racing apps
+        qsrand( QDateTime::currentMSecsSinceEpoch() % std::numeric_limits<uint>::max() );
+        QThread::sleep( 8 + static_cast <unsigned long>( static_cast <float>( qrand() ) / RAND_MAX * 10 ) );
+    }
+
+    if( inst->primary == false) {
+        d->startPrimary();
+        d->memory->unlock();
+        return;
+    }
+
+    // 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, SingleCoreApplicationPrivate::SecondaryInstance );
+        }
+        d->memory->unlock();
+        return;
+    }
+
+    d->memory->unlock();
+
+    d->connectToPrimary( timeout, SingleCoreApplicationPrivate::NewInstance );
+
+    delete d;
+
+    ::exit( EXIT_SUCCESS );
+}
+
+/**
+ * @brief Destructor
+ */
+SingleCoreApplication::~SingleCoreApplication()
+{
+    Q_D(SingleCoreApplication);
+    delete d;
+}
+
+bool SingleCoreApplication::isPrimary()
+{
+    Q_D(SingleCoreApplication);
+    return d->server != nullptr;
+}
+
+bool SingleCoreApplication::isSecondary()
+{
+    Q_D(SingleCoreApplication);
+    return d->server == nullptr;
+}
+
+quint32 SingleCoreApplication::instanceId()
+{
+    Q_D(SingleCoreApplication);
+    return d->instanceNumber;
+}
+
+qint64 SingleCoreApplication::primaryPid()
+{
+    Q_D(SingleCoreApplication);
+    return d->primaryPid();
+}
+
+bool SingleCoreApplication::sendMessage( QByteArray message, int timeout )
+{
+    Q_D(SingleCoreApplication);
+
+    // Nobody to connect to
+    if( isPrimary() ) return false;
+
+    // Make sure the socket is connected
+    d->connectToPrimary( timeout,  SingleCoreApplicationPrivate::Reconnect );
+
+    d->socket->write( message );
+    bool dataWritten = d->socket->flush();
+    d->socket->waitForBytesWritten( timeout );
+    return dataWritten;
+}

3rdparty/singleapplication/singlecoreapplication.h

@@ -0,0 +1,130 @@
+// The MIT License (MIT)
+//
+// Copyright (c) Itay Grudev 2015 - 2018
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+#ifndef SINGLECOREAPPLICATION_H
+#define SINGLECOREAPPLICATION_H
+
+#include <QtCore/QtGlobal>
+#include <QCoreApplication>
+#include <QtNetwork/QLocalSocket>
+
+class SingleCoreApplicationPrivate;
+
+/**
+ * @brief The SingleCoreApplication class handles multipe instances of the same
+ * Application
+ * @see QCoreApplication
+ */
+class SingleCoreApplication : public QCoreApplication
+{
+    Q_OBJECT
+
+    typedef QCoreApplication app_t;
+
+public:
+    /**
+     * @brief Mode of operation of SingleCoreApplication.
+     * Whether the block should be user-wide or system-wide and whether the
+     * primary instance should be notified when a secondary instance had been
+     * started.
+     * @note Operating system can restrict the shared memory blocks to the same
+     * user, in which case the User/System modes will have no effect and the
+     * block will be user wide.
+     * @enum
+     */
+    enum Mode {
+        User                    = 1 << 0,
+        System                  = 1 << 1,
+        SecondaryNotification   = 1 << 2,
+        ExcludeAppVersion       = 1 << 3,
+        ExcludeAppPath          = 1 << 4
+    };
+    Q_DECLARE_FLAGS(Options, Mode)
+
+    /**
+     * @brief Intitializes a SingleCoreApplication instance with argc command line
+     * arguments in argv
+     * @arg {int &} argc - Number of arguments in argv
+     * @arg {const char *[]} argv - Supplied command line arguments
+     * @arg {bool} allowSecondary - Whether to start the instance as secondary
+     * if there is already a primary instance.
+     * @arg {Mode} mode - Whether for the SingleCoreApplication block to be applied
+     * User wide or System wide.
+     * @arg {int} timeout - Timeout to wait in miliseconds.
+     * @note argc and argv may be changed as Qt removes arguments that it
+     * recognizes
+     * @note Mode::SecondaryNotification only works if set on both the primary
+     * instance and the secondary instance.
+     * @note The timeout is just a hint for the maximum time of blocking
+     * operations. It does not guarantee that the SingleCoreApplication
+     * initialisation will be completed in given time, though is a good hint.
+     * Usually 4*timeout would be the worst case (fail) scenario.
+     * @see See the corresponding QAPPLICATION_CLASS constructor for reference
+     */
+    explicit SingleCoreApplication( int &argc, char *argv[], bool allowSecondary = false, Options options = Mode::User, int timeout = 1000 );
+    ~SingleCoreApplication();
+
+    /**
+     * @brief Returns if the instance is the primary instance
+     * @returns {bool}
+     */
+    bool isPrimary();
+
+    /**
+     * @brief Returns if the instance is a secondary instance
+     * @returns {bool}
+     */
+    bool isSecondary();
+
+    /**
+     * @brief Returns a unique identifier for the current instance
+     * @returns {qint32}
+     */
+    quint32 instanceId();
+
+    /**
+     * @brief Returns the process ID (PID) of the primary instance
+     * @returns {qint64}
+     */
+    qint64 primaryPid();
+
+    /**
+     * @brief Sends a message to the primary instance. Returns true on success.
+     * @param {int} timeout - Timeout for connecting
+     * @returns {bool}
+     * @note sendMessage() will return false if invoked from the primary
+     * instance.
+     */
+    bool sendMessage( QByteArray message, int timeout = 100 );
+
+Q_SIGNALS:
+    void instanceStarted();
+    void receivedMessage( quint32 instanceId, QByteArray message );
+
+private:
+    SingleCoreApplicationPrivate *d_ptr;
+    Q_DECLARE_PRIVATE(SingleCoreApplication)
+};
+
+Q_DECLARE_OPERATORS_FOR_FLAGS(SingleCoreApplication::Options)
+
+#endif // SINGLECOREAPPLICATION_H

3rdparty/singleapplication/singlecoreapplication_p.cpp

@@ -0,0 +1,402 @@
+// The MIT License (MIT)
+//
+// Copyright (c) Itay Grudev 2015 - 2018
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+//
+//  W A R N I N G !!!
+//  -----------------
+//
+// This file is not part of the SingleCoreApplication API. It is used purely as an
+// implementation detail. This header file may change from version to
+// version without notice, or may even be removed.
+//
+
+#include <cstdlib>
+#include <cstddef>
+
+#include <QtCore/QDir>
+#include <QtCore/QProcess>
+#include <QtCore/QByteArray>
+#include <QtCore/QSemaphore>
+#include <QtCore/QDataStream>
+#include <QtCore/QStandardPaths>
+#include <QtCore/QCryptographicHash>
+#include <QtNetwork/QLocalServer>
+#include <QtNetwork/QLocalSocket>
+
+#include "singlecoreapplication.h"
+#include "singlecoreapplication_p.h"
+
+#ifdef Q_OS_WIN
+    #include <windows.h>
+    #include <lmcons.h>
+#endif
+
+SingleCoreApplicationPrivate::SingleCoreApplicationPrivate( SingleCoreApplication *q_ptr )
+    : q_ptr( q_ptr )
+{
+    server = nullptr;
+    socket = nullptr;
+}
+
+SingleCoreApplicationPrivate::~SingleCoreApplicationPrivate()
+{
+    if( socket != nullptr ) {
+        socket->close();
+        delete socket;
+    }
+
+    memory->lock();
+    InstancesInfo* inst = static_cast<InstancesInfo*>(memory->data());
+    if( server != nullptr ) {
+        server->close();
+        delete server;
+        inst->primary = false;
+        inst->primaryPid = -1;
+        inst->checksum = blockChecksum();
+    }
+    memory->unlock();
+
+    delete memory;
+}
+
+void SingleCoreApplicationPrivate::genBlockServerName()
+{
+    QCryptographicHash appData( QCryptographicHash::Sha256 );
+    appData.addData( "SingleCoreApplication", 17 );
+    appData.addData( SingleCoreApplication::app_t::applicationName().toUtf8() );
+    appData.addData( SingleCoreApplication::app_t::organizationName().toUtf8() );
+    appData.addData( SingleCoreApplication::app_t::organizationDomain().toUtf8() );
+
+    if( ! (options & SingleCoreApplication::Mode::ExcludeAppVersion) ) {
+        appData.addData( SingleCoreApplication::app_t::applicationVersion().toUtf8() );
+    }
+
+    if( ! (options & SingleCoreApplication::Mode::ExcludeAppPath) ) {
+#ifdef Q_OS_WIN
+        appData.addData( SingleCoreApplication::app_t::applicationFilePath().toLower().toUtf8() );
+#else
+        appData.addData( SingleCoreApplication::app_t::applicationFilePath().toUtf8() );
+#endif
+    }
+
+    // User level block requires a user specific data in the hash
+    if( options & SingleCoreApplication::Mode::User ) {
+#ifdef Q_OS_WIN
+        wchar_t username [ UNLEN + 1 ];
+        // Specifies size of the buffer on input
+        DWORD usernameLength = UNLEN + 1;
+        if( GetUserNameW( username, &usernameLength ) ) {
+            appData.addData( QString::fromWCharArray(username).toUtf8() );
+        } else {
+            appData.addData( QStandardPaths::standardLocations( QStandardPaths::HomeLocation ).join("").toUtf8() );
+        }
+#endif
+#ifdef Q_OS_UNIX
+        QProcess process;
+        process.start( "whoami" );
+        if( process.waitForFinished( 100 ) &&
+            process.exitCode() == QProcess::NormalExit) {
+            appData.addData( process.readLine() );
+        } else {
+            appData.addData(
+                QDir(
+                    QStandardPaths::standardLocations( QStandardPaths::HomeLocation ).first()
+                ).absolutePath().toUtf8()
+            );
+        }
+#endif
+    }
+
+    // Replace the backslash in RFC 2045 Base64 [a-zA-Z0-9+/=] to comply with
+    // server naming requirements.
+    blockServerName = appData.result().toBase64().replace("/", "_");
+}
+
+void SingleCoreApplicationPrivate::initializeMemoryBlock()
+{
+    InstancesInfo* inst = static_cast<InstancesInfo*>( memory->data() );
+    inst->primary = false;
+    inst->secondary = 0;
+    inst->primaryPid = -1;
+    inst->checksum = blockChecksum();
+}
+
+void SingleCoreApplicationPrivate::startPrimary()
+{
+    Q_Q(SingleCoreApplication);
+
+    // Successful creation means that no main process exists
+    // So we start a QLocalServer to listen for connections
+    QLocalServer::removeServer( blockServerName );
+    server = new QLocalServer();
+
+    // Restrict access to the socket according to the
+    // SingleCoreApplication::Mode::User flag on User level or no restrictions
+    if( options & SingleCoreApplication::Mode::User ) {
+      server->setSocketOptions( QLocalServer::UserAccessOption );
+    } else {
+      server->setSocketOptions( QLocalServer::WorldAccessOption );
+    }
+
+    server->listen( blockServerName );
+    QObject::connect(
+        server,
+        &QLocalServer::newConnection,
+        this,
+        &SingleCoreApplicationPrivate::slotConnectionEstablished
+    );
+
+    // Reset the number of connections
+    InstancesInfo* inst = static_cast <InstancesInfo*>( memory->data() );
+
+    inst->primary = true;
+    inst->primaryPid = q->applicationPid();
+    inst->checksum = blockChecksum();
+
+    instanceNumber = 0;
+}
+
+void SingleCoreApplicationPrivate::startSecondary()
+{
+}
+
+void SingleCoreApplicationPrivate::connectToPrimary( int msecs, ConnectionType connectionType )
+{
+    // Connect to the Local Server of the Primary Instance if not already
+    // connected.
+    if( socket == nullptr ) {
+        socket = new QLocalSocket();
+    }
+
+    // If already connected - we are done;
+    if( socket->state() == QLocalSocket::ConnectedState )
+        return;
+
+    // If not connect
+    if( socket->state() == QLocalSocket::UnconnectedState ||
+        socket->state() == QLocalSocket::ClosingState ) {
+        socket->connectToServer( blockServerName );
+    }
+
+    // Wait for being connected
+    if( socket->state() == QLocalSocket::ConnectingState ) {
+        socket->waitForConnected( msecs );
+    }
+
+    // Initialisation message according to the SingleCoreApplication protocol
+    if( socket->state() == QLocalSocket::ConnectedState ) {
+        // Notify the parent that a new instance had been started;
+        QByteArray initMsg;
+        QDataStream writeStream(&initMsg, QIODevice::WriteOnly);
+
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 6, 0))
+        writeStream.setVersion(QDataStream::Qt_5_6);
+#endif
+
+        writeStream << blockServerName.toLatin1();
+        writeStream << static_cast<quint8>(connectionType);
+        writeStream << instanceNumber;
+        quint16 checksum = qChecksum(initMsg.constData(), static_cast<quint32>(initMsg.length()));
+        writeStream << checksum;
+
+        // The header indicates the message length that follows
+        QByteArray header;
+        QDataStream headerStream(&header, QIODevice::WriteOnly);
+
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 6, 0))
+        headerStream.setVersion(QDataStream::Qt_5_6);
+#endif
+        headerStream << static_cast <quint64>( initMsg.length() );
+
+        socket->write( header );
+        socket->write( initMsg );
+        socket->flush();
+        socket->waitForBytesWritten( msecs );
+    }
+}
+
+quint16 SingleCoreApplicationPrivate::blockChecksum()
+{
+    return qChecksum(
+       static_cast <const char *>( memory->data() ),
+       offsetof( InstancesInfo, checksum )
+   );
+}
+
+qint64 SingleCoreApplicationPrivate::primaryPid()
+{
+    qint64 pid;
+
+    memory->lock();
+    InstancesInfo* inst = static_cast<InstancesInfo*>( memory->data() );
+    pid = inst->primaryPid;
+    memory->unlock();
+
+    return pid;
+}
+
+/**
+ * @brief Executed when a connection has been made to the LocalServer
+ */
+void SingleCoreApplicationPrivate::slotConnectionEstablished()
+{
+    QLocalSocket *nextConnSocket = server->nextPendingConnection();
+    connectionMap.insert(nextConnSocket, ConnectionInfo());
+
+    QObject::connect(nextConnSocket, &QLocalSocket::aboutToClose,
+        [nextConnSocket, this]() {
+            auto &info = connectionMap[nextConnSocket];
+            Q_EMIT this->slotClientConnectionClosed( nextConnSocket, info.instanceId );
+        }
+    );
+
+    QObject::connect(nextConnSocket, &QLocalSocket::disconnected,
+        [nextConnSocket, this](){
+            connectionMap.remove(nextConnSocket);
+            nextConnSocket->deleteLater();
+        }
+    );
+
+    QObject::connect(nextConnSocket, &QLocalSocket::readyRead,
+        [nextConnSocket, this]() {
+            auto &info = connectionMap[nextConnSocket];
+            switch(info.stage) {
+            case StageHeader:
+                readInitMessageHeader(nextConnSocket);
+                break;
+            case StageBody:
+                readInitMessageBody(nextConnSocket);
+                break;
+            case StageConnected:
+                Q_EMIT this->slotDataAvailable( nextConnSocket, info.instanceId );
+                break;
+            default:
+                break;
+            };
+        }
+    );
+}
+
+void SingleCoreApplicationPrivate::readInitMessageHeader( QLocalSocket *sock )
+{
+    if (!connectionMap.contains( sock )) {
+        return;
+    }
+
+    if( sock->bytesAvailable() < ( qint64 )sizeof( quint64 ) ) {
+        return;
+    }
+
+    QDataStream headerStream( sock );
+
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 6, 0))
+    headerStream.setVersion( QDataStream::Qt_5_6 );
+#endif
+
+    // Read the header to know the message length
+    quint64 msgLen = 0;
+    headerStream >> msgLen;
+    ConnectionInfo &info = connectionMap[sock];
+    info.stage = StageBody;
+    info.msgLen = msgLen;
+
+    if ( sock->bytesAvailable() >= (qint64) msgLen ) {
+        readInitMessageBody( sock );
+    }
+}
+
+void SingleCoreApplicationPrivate::readInitMessageBody( QLocalSocket *sock )
+{
+    Q_Q(SingleCoreApplication);
+
+    if (!connectionMap.contains( sock )) {
+        return;
+    }
+
+    ConnectionInfo &info = connectionMap[sock];
+    if( sock->bytesAvailable() < ( qint64 )info.msgLen ) {
+        return;
+    }
+
+    // Read the message body
+    QByteArray msgBytes = sock->read(info.msgLen);
+    QDataStream readStream(msgBytes);
+
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 6, 0))
+    readStream.setVersion( QDataStream::Qt_5_6 );
+#endif
+
+    // server name
+    QByteArray latin1Name;
+    readStream >> latin1Name;
+
+    // connection type
+    ConnectionType connectionType = InvalidConnection;
+    quint8 connTypeVal = InvalidConnection;
+    readStream >> connTypeVal;
+    connectionType = static_cast <ConnectionType>( connTypeVal );
+
+    // instance id
+    quint32 instanceId = 0;
+    readStream >> instanceId;
+
+    // checksum
+    quint16 msgChecksum = 0;
+    readStream >> msgChecksum;
+
+    const quint16 actualChecksum = qChecksum( msgBytes.constData(), static_cast<quint32>( msgBytes.length() - sizeof( quint16 ) ) );
+
+    bool isValid = readStream.status() == QDataStream::Ok &&
+                   QLatin1String(latin1Name) == blockServerName &&
+                   msgChecksum == actualChecksum;
+
+    if( !isValid ) {
+        sock->close();
+        return;
+    }
+
+    info.instanceId = instanceId;
+    info.stage = StageConnected;
+
+    if( connectionType == NewInstance ||
+        ( connectionType == SecondaryInstance &&
+          options & SingleCoreApplication::Mode::SecondaryNotification ) )
+    {
+        Q_EMIT q->instanceStarted();
+    }
+
+    if (sock->bytesAvailable() > 0) {
+        Q_EMIT this->slotDataAvailable( sock, instanceId );
+    }
+}
+
+void SingleCoreApplicationPrivate::slotDataAvailable( QLocalSocket *dataSocket, quint32 instanceId )
+{
+    Q_Q(SingleCoreApplication);
+    Q_EMIT q->receivedMessage( instanceId, dataSocket->readAll() );
+}
+
+void SingleCoreApplicationPrivate::slotClientConnectionClosed( QLocalSocket *closedSocket, quint32 instanceId )
+{
+    if( closedSocket->bytesAvailable() > 0 )
+        Q_EMIT slotDataAvailable( closedSocket, instanceId  );
+}

3rdparty/singleapplication/singlecoreapplication_p.h

@@ -0,0 +1,99 @@
+// The MIT License (MIT)
+//
+// Copyright (c) Itay Grudev 2015 - 2016
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+//
+//  W A R N I N G !!!
+//  -----------------
+//
+// This file is not part of the SingleCoreApplication API. It is used purely as an
+// implementation detail. This header file may change from version to
+// version without notice, or may even be removed.
+//
+
+#ifndef SINGLECOREAPPLICATION_P_H
+#define SINGLECOREAPPLICATION_P_H
+
+#include <QtCore/QSharedMemory>
+#include <QtNetwork/QLocalServer>
+#include <QtNetwork/QLocalSocket>
+#include "singlecoreapplication.h"
+
+struct InstancesInfo {
+    bool primary;
+    quint32 secondary;
+    qint64 primaryPid;
+    quint16 checksum;
+};
+
+struct ConnectionInfo {
+    explicit ConnectionInfo() :
+        msgLen(0), instanceId(0), stage(0) {}
+    qint64 msgLen;
+    quint32 instanceId;
+    quint8 stage;
+};
+
+class SingleCoreApplicationPrivate : public QObject {
+Q_OBJECT
+public:
+    enum ConnectionType : quint8 {
+        InvalidConnection = 0,
+        NewInstance = 1,
+        SecondaryInstance = 2,
+        Reconnect = 3
+    };
+    enum ConnectionStage : quint8 {
+        StageHeader = 0,
+        StageBody = 1,
+        StageConnected = 2,
+    };
+    Q_DECLARE_PUBLIC(SingleCoreApplication)
+
+    SingleCoreApplicationPrivate( SingleCoreApplication *q_ptr );
+     ~SingleCoreApplicationPrivate();
+
+    void genBlockServerName();
+    void initializeMemoryBlock();
+    void startPrimary();
+    void startSecondary();
+    void connectToPrimary(int msecs, ConnectionType connectionType );
+    quint16 blockChecksum();
+    qint64 primaryPid();
+    void readInitMessageHeader(QLocalSocket *socket);
+    void readInitMessageBody(QLocalSocket *socket);
+
+    SingleCoreApplication *q_ptr;
+    QSharedMemory *memory;
+    QLocalSocket *socket;
+    QLocalServer *server;
+    quint32 instanceNumber;
+    QString blockServerName;
+    SingleCoreApplication::Options options;
+    QMap<QLocalSocket*, ConnectionInfo> connectionMap;
+
+public Q_SLOTS:
+    void slotConnectionEstablished();
+    void slotDataAvailable( QLocalSocket*, quint32 );
+    void slotClientConnectionClosed( QLocalSocket*, quint32 );
+};
+
+#endif // SINGLECOREAPPLICATION_P_H