QtSsh

client/3rd/QtSsh/src/ssh/sshconnectionmanager.cpp

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+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#include "sshconnectionmanager.h"
+
+#include "sshconnection.h"
+
+#include <QCoreApplication>
+#include <QList>
+#include <QMutex>
+#include <QMutexLocker>
+#include <QObject>
+#include <QThread>
+#include <QTimer>
+
+namespace QSsh {
+namespace Internal {
+class UnaquiredConnection {
+public:
+    UnaquiredConnection(SshConnection *conn) : connection(conn), scheduledForRemoval(false) {}
+
+    SshConnection *connection;
+    bool scheduledForRemoval;
+};
+bool operator==(const UnaquiredConnection &c1, const UnaquiredConnection &c2) {
+    return c1.connection == c2.connection;
+}
+bool operator!=(const UnaquiredConnection &c1, const UnaquiredConnection &c2) {
+    return !(c1 == c2);
+}
+
+class SshConnectionManager : public QObject
+{
+    Q_OBJECT
+
+public:
+    SshConnectionManager()
+    {
+        moveToThread(QCoreApplication::instance()->thread());
+        connect(&m_removalTimer, &QTimer::timeout,
+                this, &SshConnectionManager::removeInactiveConnections);
+        m_removalTimer.start(150000); // For a total timeout of five minutes.
+    }
+
+    ~SshConnectionManager()
+    {
+        foreach (const UnaquiredConnection &connection, m_unacquiredConnections) {
+            disconnect(connection.connection, 0, this, 0);
+            delete connection.connection;
+        }
+
+        QSSH_ASSERT(m_acquiredConnections.isEmpty());
+        QSSH_ASSERT(m_deprecatedConnections.isEmpty());
+    }
+
+    SshConnection *acquireConnection(const SshConnectionParameters &sshParams)
+    {
+        QMutexLocker locker(&m_listMutex);
+
+        // Check in-use connections:
+        foreach (SshConnection * const connection, m_acquiredConnections) {
+            if (connection->connectionParameters() != sshParams)
+                continue;
+
+            if (connection->thread() != QThread::currentThread())
+                continue;
+
+            if (m_deprecatedConnections.contains(connection)) // we were asked to no longer use this one...
+                continue;
+
+            m_acquiredConnections.append(connection);
+            return connection;
+        }
+
+        // Check cached open connections:
+        foreach (const UnaquiredConnection &c, m_unacquiredConnections) {
+            SshConnection * const connection = c.connection;
+            if (connection->state() != SshConnection::Connected
+                    || connection->connectionParameters() != sshParams)
+                continue;
+
+            if (connection->thread() != QThread::currentThread()) {
+                if (connection->channelCount() != 0)
+                    continue;
+                QMetaObject::invokeMethod(this, "switchToCallerThread",
+                    Qt::BlockingQueuedConnection,
+                    Q_ARG(SshConnection *, connection),
+                    Q_ARG(QObject *, QThread::currentThread()));
+            }
+
+            m_unacquiredConnections.removeOne(c);
+            m_acquiredConnections.append(connection);
+            return connection;
+        }
+
+        // create a new connection:
+        SshConnection * const connection = new SshConnection(sshParams);
+        connect(connection, &SshConnection::disconnected,
+                this, &SshConnectionManager::cleanup);
+        m_acquiredConnections.append(connection);
+
+        return connection;
+    }
+
+    void releaseConnection(SshConnection *connection)
+    {
+        QMutexLocker locker(&m_listMutex);
+
+        const bool wasAquired = m_acquiredConnections.removeOne(connection);
+        QSSH_ASSERT_AND_RETURN(wasAquired);
+        if (m_acquiredConnections.contains(connection))
+            return;
+
+        bool doDelete = false;
+        connection->moveToThread(QCoreApplication::instance()->thread());
+        if (m_deprecatedConnections.removeOne(connection)
+                || connection->state() != SshConnection::Connected) {
+            doDelete = true;
+        } else {
+            QSSH_ASSERT_AND_RETURN(!m_unacquiredConnections.contains(UnaquiredConnection(connection)));
+
+            // It can happen that two or more connections with the same parameters were acquired
+            // if the clients were running in different threads. Only keep one of them in
+            // such a case.
+            bool haveConnection = false;
+            foreach (const UnaquiredConnection &c, m_unacquiredConnections) {
+                if (c.connection->connectionParameters() == connection->connectionParameters()) {
+                    haveConnection = true;
+                    break;
+                }
+            }
+            if (!haveConnection) {
+                connection->closeAllChannels(); // Clean up after neglectful clients.
+                m_unacquiredConnections.append(UnaquiredConnection(connection));
+            } else {
+                doDelete = true;
+            }
+        }
+
+        if (doDelete) {
+            disconnect(connection, 0, this, 0);
+            m_deprecatedConnections.removeAll(connection);
+            connection->deleteLater();
+        }
+    }
+
+    void forceNewConnection(const SshConnectionParameters &sshParams)
+    {
+        QMutexLocker locker(&m_listMutex);
+
+        for (int i = 0; i < m_unacquiredConnections.count(); ++i) {
+            SshConnection * const connection = m_unacquiredConnections.at(i).connection;
+            if (connection->connectionParameters() == sshParams) {
+                disconnect(connection, 0, this, 0);
+                delete connection;
+                m_unacquiredConnections.removeAt(i);
+                break;
+            }
+        }
+
+        foreach (SshConnection * const connection, m_acquiredConnections) {
+            if (connection->connectionParameters() == sshParams) {
+                if (!m_deprecatedConnections.contains(connection))
+                    m_deprecatedConnections.append(connection);
+            }
+        }
+    }
+
+private:
+    Q_INVOKABLE void switchToCallerThread(SshConnection *connection, QObject *threadObj)
+    {
+        connection->moveToThread(qobject_cast<QThread *>(threadObj));
+    }
+
+    void cleanup()
+    {
+        QMutexLocker locker(&m_listMutex);
+
+        SshConnection *currentConnection = qobject_cast<SshConnection *>(sender());
+        if (!currentConnection)
+            return;
+
+        if (m_unacquiredConnections.removeOne(UnaquiredConnection(currentConnection))) {
+            disconnect(currentConnection, 0, this, 0);
+            currentConnection->deleteLater();
+        }
+    }
+
+    void removeInactiveConnections()
+    {
+        QMutexLocker locker(&m_listMutex);
+        for (int i = m_unacquiredConnections.count() - 1; i >= 0; --i) {
+            UnaquiredConnection &c = m_unacquiredConnections[i];
+            if (c.scheduledForRemoval) {
+                disconnect(c.connection, 0, this, 0);
+                c.connection->deleteLater();
+                m_unacquiredConnections.removeAt(i);
+            } else {
+                c.scheduledForRemoval = true;
+            }
+        }
+    }
+
+private:
+    // We expect the number of concurrently open connections to be small.
+    // If that turns out to not be the case, we can still use a data
+    // structure with faster access.
+    QList<UnaquiredConnection> m_unacquiredConnections;
+
+    // Can contain the same connection more than once; this acts as a reference count.
+    QList<SshConnection *> m_acquiredConnections;
+
+    QList<SshConnection *> m_deprecatedConnections;
+    QMutex m_listMutex;
+    QTimer m_removalTimer;
+};
+
+} // namespace Internal
+
+static QMutex instanceMutex;
+
+static Internal::SshConnectionManager &instance()
+{
+    static Internal::SshConnectionManager manager;
+    return manager;
+}
+
+SshConnection *acquireConnection(const SshConnectionParameters &sshParams)
+{
+    QMutexLocker locker(&instanceMutex);
+    return instance().acquireConnection(sshParams);
+}
+
+void releaseConnection(SshConnection *connection)
+{
+    QMutexLocker locker(&instanceMutex);
+    instance().releaseConnection(connection);
+}
+
+void forceNewConnection(const SshConnectionParameters &sshParams)
+{
+    QMutexLocker locker(&instanceMutex);
+    instance().forceNewConnection(sshParams);
+}
+
+} // namespace QSsh
+
+#include "sshconnectionmanager.moc"