client-qml: add initial commit
Change-Id: I32bfdd2a618aa7ac6181da2697e241667b010aab
diff --git a/src/runguard.cpp b/src/runguard.cpp
new file mode 100644
index 0000000..4d22959
--- /dev/null
+++ b/src/runguard.cpp
@@ -0,0 +1,130 @@
+/*
+ * Copyright (C) 2019-2020 by Savoir-faire Linux
+ * Author: Andreas Traczyk <andreas.traczyk@savoirfairelinux.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+// Based on: https://stackoverflow.com/a/28172162
+
+#include "runguard.h"
+#include <QCryptographicHash>
+
+namespace {
+
+QString
+generateKeyHash(const QString &key, const QString &salt)
+{
+ QByteArray data;
+
+ data.append(key.toUtf8());
+ data.append(salt.toUtf8());
+ data = QCryptographicHash::hash(data, QCryptographicHash::Sha1).toHex();
+
+ return data;
+}
+
+} // namespace
+
+RunGuard::RunGuard(const QString &key)
+ : key_(key)
+ , memLockKey_(generateKeyHash(key, "_memLockKey"))
+ , sharedmemKey_(generateKeyHash(key, "_sharedmemKey"))
+ , sharedMem_(sharedmemKey_)
+ , memLock_(memLockKey_, 1)
+{}
+
+RunGuard::~RunGuard()
+{
+ release();
+}
+
+void
+RunGuard::tryRestorePrimaryInstance()
+{
+ /*
+ * TODO: relaunch application
+ */
+}
+
+bool
+RunGuard::isAnotherRunning()
+{
+ if (sharedMem_.isAttached())
+ return false;
+
+ memLock_.acquire();
+ const bool isRunning = sharedMem_.attach();
+ if (isRunning)
+ sharedMem_.detach();
+ memLock_.release();
+
+ return isRunning;
+}
+
+bool
+RunGuard::tryToRun()
+{
+#ifdef Q_OS_WIN
+ if (isAnotherRunning()) {
+ /*
+ * This is a secondary instance,
+ * connect to the primary instance to trigger a restore
+ * then fail.
+ */
+ if (socket_ == nullptr) {
+ socket_ = new QLocalSocket();
+ }
+ if (socket_->state() == QLocalSocket::UnconnectedState
+ || socket_->state() == QLocalSocket::ClosingState) {
+ socket_->connectToServer(key_);
+ }
+ if (socket_->state() == QLocalSocket::ConnectingState) {
+ socket_->waitForConnected();
+ }
+ return false;
+ }
+
+ memLock_.acquire();
+ const bool result = sharedMem_.create(sizeof(quint64));
+ memLock_.release();
+ if (!result) {
+ release();
+ return false;
+ }
+
+ /*
+ * This is the primary instance,
+ * listen for subsequent instances.
+ */
+ QLocalServer::removeServer(key_);
+ server_ = new QLocalServer();
+ server_->setSocketOptions(QLocalServer::UserAccessOption);
+ server_->listen(key_);
+ QObject::connect(server_,
+ &QLocalServer::newConnection,
+ this,
+ &RunGuard::tryRestorePrimaryInstance);
+#endif
+
+ return true;
+}
+
+void
+RunGuard::release()
+{
+ memLock_.acquire();
+ if (sharedMem_.isAttached())
+ sharedMem_.detach();
+ memLock_.release();
+}
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