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 /****************************************************************************
 **
 ** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
 ** Contact: http://www.qt-project.org/legal
 **
 ** This file is part of Qt Creator.
 **
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 ** accordance with the commercial license agreement provided with the
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 ** use the contact form at https://www.qt.io/contact-us.
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 ** GNU Lesser General Public License Usage
 ** Alternatively, this file may be used under the terms of the GNU Lesser
 ** General Public License version 2.1 or version 3 as published by the Free
 ** Software Foundation and appearing in the file LICENSE.LGPLv21 and
 ** LICENSE.LGPLv3 included in the packaging of this file.  Please review the
 ** following information to ensure the GNU Lesser General Public License
 ** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
 ** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
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 ** rights.  These rights are described in the Digia Qt LGPL Exception
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 #include "qtlocalpeer.h"
 
 #include <QCoreApplication>
 #include <QDataStream>
 #include <QTime>
 
 #if defined(Q_OS_WIN)
 #include <QLibrary>
 #include <qt_windows.h>
 typedef BOOL(WINAPI*PProcessIdToSessionId)(DWORD,DWORD*);
 static PProcessIdToSessionId pProcessIdToSessionId = 0;
 #endif
 
 #if defined(Q_OS_UNIX)
 #include <time.h>
 #include <unistd.h>
 #endif
 
 
 
 static const char ack[] = "ack";
 
 QString QtLocalPeer::appSessionId(const QString &appId)
 {
     QByteArray idc = appId.toUtf8();
     quint16 idNum = qChecksum(idc.constData(), idc.size());
     //### could do: two 16bit checksums over separate halves of id, for a 32bit result - improved uniqueness probability. Every-other-char split would be best.
 
     QString res = QLatin1String("qtsingleapplication-")
                  + QString::number(idNum, 16);
 #if defined(Q_OS_WIN)
     if (!pProcessIdToSessionId) {
         QLibrary lib(QLatin1String("kernel32"));
         pProcessIdToSessionId = (PProcessIdToSessionId)lib.resolve("ProcessIdToSessionId");
     }
     if (pProcessIdToSessionId) {
         DWORD sessionId = 0;
         pProcessIdToSessionId(GetCurrentProcessId(), &sessionId);
         res += QLatin1Char('-') + QString::number(sessionId, 16);
     }
 #else
     res += QLatin1Char('-') + QString::number(::getuid(), 16);
 #endif
     return res;
 }
 
 QtLocalPeer::QtLocalPeer(QObject *parent, const QString &appId)
     : QObject(parent), id(appId)
 {
     if (id.isEmpty())
         id = QCoreApplication::applicationFilePath();  //### On win, check if this returns .../argv[0] without casefolding; .\MYAPP == .\myapp on Win
 
     socketName = appSessionId(id);
     server = new QLocalServer(this);
     QString lockName = QDir(QDir::tempPath()).absolutePath()
                        + QLatin1Char('/') + socketName
                        + QLatin1String("-lockfile");
     lockFile.setFileName(lockName);
     lockFile.open(QIODevice::ReadWrite);
 }
 
 bool QtLocalPeer::isClient()
 {
     if (lockFile.isLocked())
         return false;
 
     if (!lockFile.lock(QtLockedFile::WriteLock, false))
         return true;
 
     if (!QLocalServer::removeServer(socketName))
         qWarning("QtSingleCoreApplication: could not cleanup socket");
     bool res = server->listen(socketName);
     if (!res)
         qWarning("QtSingleCoreApplication: listen on local socket failed, %s", qPrintable(server->errorString()));
     QObject::connect(server, SIGNAL(newConnection()), SLOT(receiveConnection()));
     return false;
 }
 
 bool QtLocalPeer::sendMessage(const QByteArray &message, int timeout, bool block)
 {
     if (!isClient())
         return false;
 
     QLocalSocket socket;
     bool connOk = false;
     for (int i = 0; i < 2; i++) {
         // Try twice, in case the other instance is just starting up
         socket.connectToServer(socketName);
         connOk = socket.waitForConnected(timeout/2);
         if (connOk || i)
             break;
         int ms = 250;
 #if defined(Q_OS_WIN)
         Sleep(DWORD(ms));
 #else
         struct timespec ts = { ms / 1000, (ms % 1000) * 1000 * 1000 };
         nanosleep(&ts, 0);
 #endif
     }
     if (!connOk)
         return false;
 
     QByteArray uMsg(message);
     QDataStream ds(&socket);
     ds.writeBytes(uMsg.constData(), uMsg.size());
     bool res = socket.waitForBytesWritten(timeout);
     res &= socket.waitForReadyRead(timeout); // wait for ack
     res &= (socket.read(qstrlen(ack)) == ack);
     if (block) // block until peer disconnects
         socket.waitForDisconnected(-1);
     return res;
 }
 
 void QtLocalPeer::receiveConnection()
 {
     QLocalSocket* socket = server->nextPendingConnection();
     if (!socket)
         return;
 
     // Why doesn't Qt have a blocking stream that takes care of this shait???
     while (socket->bytesAvailable() < static_cast<int>(sizeof(quint32))) {
         if (!socket->isValid()) // stale request
             return;
         socket->waitForReadyRead(1000);
     }
     QDataStream ds(socket);
     QByteArray uMsg;
     quint32 remaining;
     ds >> remaining;
     uMsg.resize(remaining);
     int got = 0;
     char* uMsgBuf = uMsg.data();
     //dbgKrita << "RCV: remaining" << remaining;
     do {
         got = ds.readRawData(uMsgBuf, remaining);
         remaining -= got;
         uMsgBuf += got;
         //qDebug() << "RCV: got" << got << "remaining" << remaining;
     } while (remaining && got >= 0 && socket->waitForReadyRead(2000));
     //### error check: got<0
     if (got < 0) {
         qWarning() << "QtLocalPeer: Message reception failed" << socket->errorString();
         delete socket;
         return;
     }
     // ### async this
     socket->write(ack, qstrlen(ack));
     socket->waitForBytesWritten(1000);
     emit messageReceived(uMsg, socket); // ##(might take a long time to return)
 }