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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0+ OR GPL-3.0 WITH Qt-GPL-exception-1.0
#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
namespace SharedTools {
static const char ack[] = "ack";
QString QtLocalPeer::appSessionId(const QString &appId)
{
const QByteArray idc = appId.toUtf8();
const quint16 idNum = qChecksum(idc);
//### could do: two 16bit checksums over separate halves of id, for a 32bit result - improved uniqeness 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, &QLocalServer::newConnection, this, &QtLocalPeer::receiveConnection);
return false;
}
bool QtLocalPeer::sendMessage(const QString &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, NULL);
#endif
}
if (!connOk)
return false;
QByteArray uMsg(message.toUtf8());
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();
//qDebug() << "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
QString message = QString::fromUtf8(uMsg.constData(), uMsg.size());
socket->write(ack, qstrlen(ack));
socket->waitForBytesWritten(1000);
emit messageReceived(message, socket); // ##(might take a long time to return)
}
} // namespace SharedTools
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