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nheko/subprojects/SingleApplication-3.3.0/singleapplication.cpp

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// The MIT License (MIT)
//
// 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
// 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 <QtCore/QElapsedTimer>
#include <QtCore/QByteArray>
#include <QtCore/QSharedMemory>
#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 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 );
#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;
#endif
// Store the current mode of the program
d->options = options;
// 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;
#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
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();
}
}
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 ){
// If the shared memory block's checksum is valid continue
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();
}
// 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();
}
}
if( inst->primary == false ){
d->startPrimary();
if( ! d->memory->unlock() ){
qDebug() << "SingleApplication: Unable to unlock memory after primary start.";
qDebug() << d->memory->errorString();
}
return;
}
// 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( ! d->memory->unlock() ){
qDebug() << "SingleApplication: Unable to unlock memory at end of execution.";
qDebug() << d->memory->errorString();
}
d->connectToPrimary( timeout, SingleApplicationPrivate::NewInstance );
delete d;
::exit( EXIT_SUCCESS );
}
SingleApplication::~SingleApplication()
{
Q_D( SingleApplication );
delete d;
}
/**
* Checks if the current application instance is primary.
* @return Returns true if the instance is primary, false otherwise.
*/
bool SingleApplication::isPrimary() const
{
Q_D( const SingleApplication );
return d->server != nullptr;
}
/**
* Checks if the current application instance is secondary.
* @return Returns true if the instance is secondary, false otherwise.
*/
bool SingleApplication::isSecondary() const
{
Q_D( const SingleApplication );
return d->server == nullptr;
}
/**
* 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( const SingleApplication );
return d->instanceNumber;
}
/**
* 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( const SingleApplication );
return d->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( const SingleApplication );
return d->primaryUser();
}
/**
* Returns the username the current instance is running as.
* @return Returns the username the current instance is running as.
*/
QString SingleApplication::currentUser() const
{
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;
return d->writeConfirmedMessage( timeout, message );
}
/**
* 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();
}