// 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 is a modified version of SingleApplication, // The original version is at: // // https://github.com/itay-grudev/SingleApplication // // #include #include #include #include #include #include #include #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(d->memory->data()); QElapsedTimer 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::max()); QThread::sleep(8 + static_cast (static_cast (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->waitForBytesWritten(timeout); d->socket->flush(); return dataWritten; }