QmlDebug: Move QmlDebugConnection into own file

Change-Id: I761658de7c19754cfaadf8cbbad7596a9bcdfbf3
Reviewed-by: hjk <hjk@qt.io>

8 files changed, 527 insertions, 441 deletions

diff --git a/src/libs/qmldebug/declarativetoolsclient.cpp b/src/libs/qmldebug/declarativetoolsclient.cpp
index 29060cdea2..cf59e01358 100644
--- a/src/libs/qmldebug/declarativetoolsclient.cpp
+++ b/src/libs/qmldebug/declarativetoolsclient.cpp
@@ -24,6 +24,7 @@
 ****************************************************************************/
 
 #include "declarativetoolsclient.h"
+#include "qmldebugconnection.h"
 #include <QMetaEnum>
 #include <QStringList>
 
diff --git a/src/libs/qmldebug/qmldebug-lib.pri b/src/libs/qmldebug/qmldebug-lib.pri
index fe67974606..28c269ab35 100644
--- a/src/libs/qmldebug/qmldebug-lib.pri
+++ b/src/libs/qmldebug/qmldebug-lib.pri
@@ -19,7 +19,8 @@ HEADERS += \
     $$PWD/declarativetoolsclient.h \
     $$PWD/qmltoolsclient.h \
     $$PWD/qmlenginecontrolclient.h \
-    $$PWD/qmldebugcommandlinearguments.h
+    $$PWD/qmldebugcommandlinearguments.h \
+    $$PWD/qmldebugconnection.h
 
 SOURCES += \
     $$PWD/qmldebugclient.cpp \
@@ -31,5 +32,5 @@ SOURCES += \
     $$PWD/declarativetoolsclient.cpp \
     $$PWD/qmltoolsclient.cpp \
     $$PWD/declarativeenginedebugclient.cpp \
-    $$PWD/qmlenginecontrolclient.cpp
-
+    $$PWD/qmlenginecontrolclient.cpp \
+    $$PWD/qmldebugconnection.cpp
diff --git a/src/libs/qmldebug/qmldebug.qbs b/src/libs/qmldebug/qmldebug.qbs
index b681e54579..2f5c30e163 100644
--- a/src/libs/qmldebug/qmldebug.qbs
+++ b/src/libs/qmldebug/qmldebug.qbs
@@ -27,6 +27,8 @@ Project {
             "qmldebugclient.cpp",
             "qmldebugclient.h",
             "qmldebugcommandlinearguments.h",
+            "qmldebugconnection.cpp",
+            "qmldebugconnection.h",
             "qmldebugconstants.h",
             "qmlenginecontrolclient.cpp",
             "qmlenginecontrolclient.h",
diff --git a/src/libs/qmldebug/qmldebugclient.cpp b/src/libs/qmldebug/qmldebugclient.cpp
index ffa21a458c..d6957bec7e 100644
--- a/src/libs/qmldebug/qmldebugclient.cpp
+++ b/src/libs/qmldebug/qmldebugclient.cpp
@@ -24,25 +24,16 @@
 ****************************************************************************/
 
 #include "qmldebugclient.h"
-
+#include "qmldebugconnection.h"
 #include "qpacketprotocol.h"
 
 #include <qdebug.h>
 #include <qstringlist.h>
-#include <qnetworkproxy.h>
-#include <qlocalserver.h>
-#include <qlocalsocket.h>
 
 #include <QPointer>
 
 namespace QmlDebug {
 
-const int protocolVersion = 1;
-const int minimumDataStreamVersion = QDataStream::Qt_4_7;
-
-const QString serverId = QLatin1String("QDeclarativeDebugServer");
-const QString clientId = QLatin1String("QDeclarativeDebugClient");
-
 class QmlDebugClientPrivate
 {
 public:
@@ -52,387 +43,6 @@ public:
     QPointer<QmlDebugConnection> connection;
 };
 
-class QmlDebugConnectionPrivate
-{
-public:
-    QmlDebugConnectionPrivate();
-    QPacketProtocol *protocol;
-    QLocalServer *server;
-    QIODevice *device; // Currently a QTcpSocket or a QLocalSocket
-
-    bool gotHello;
-    QHash <QString, float> serverPlugins;
-    QHash<QString, QmlDebugClient *> plugins;
-
-    int currentDataStreamVersion;
-    int maximumDataStreamVersion;
-
-    void advertisePlugins();
-    void flush();
-};
-
-static QString socketStateToString(QAbstractSocket::SocketState state)
-{
-    QString stateString;
-    QDebug(&stateString) << state;
-    return QmlDebugConnection::tr("Socket state changed to %1").arg(stateString);
-}
-
-static QString socketErrorToString(QAbstractSocket::SocketError error)
-{
-    QString errorString;
-    QDebug(&errorString) << error;
-    return QmlDebugConnection::tr("Error: %1").arg(errorString);
-}
-
-QmlDebugConnectionPrivate::QmlDebugConnectionPrivate() :
-    protocol(0), server(0), device(0), gotHello(false),
-    currentDataStreamVersion(minimumDataStreamVersion),
-    maximumDataStreamVersion(QDataStream::Qt_DefaultCompiledVersion)
-{
-}
-
-void QmlDebugConnectionPrivate::advertisePlugins()
-{
-    if (!gotHello)
-        return;
-
-    QPacket pack(currentDataStreamVersion);
-    pack << serverId << 1 << plugins.keys();
-    protocol->send(pack.data());
-    flush();
-}
-
-void QmlDebugConnection::socketConnected()
-{
-    Q_D(QmlDebugConnection);
-    QPacket pack(d->currentDataStreamVersion);
-    pack << serverId << 0 << protocolVersion << d->plugins.keys() << d->maximumDataStreamVersion
-         << true; // We accept multiple messages per packet
-    d->protocol->send(pack.data());
-    d->flush();
-}
-
-void QmlDebugConnection::socketDisconnected()
-{
-    Q_D(QmlDebugConnection);
-    if (d->gotHello) {
-        d->gotHello = false;
-        QHash<QString, QmlDebugClient*>::iterator iter = d->plugins.begin();
-        for (; iter != d->plugins.end(); ++iter)
-            iter.value()->stateChanged(QmlDebugClient::NotConnected);
-        emit disconnected();
-    } else if (d->device) {
-        emit connectionFailed();
-    }
-    if (d->protocol) {
-        d->protocol->disconnect();
-        d->protocol->deleteLater();
-        d->protocol = 0;
-    }
-    if (d->device) {
-        // Don't allow any "connected()" or "disconnected()" signals to be triggered anymore.
-        // As the protocol is gone this would lead to crashes.
-        d->device->disconnect();
-        // Don't immediately delete it as it may do some cleanup on returning from a signal.
-        d->device->deleteLater();
-        d->device = 0;
-    }
-}
-
-void QmlDebugConnection::protocolReadyRead()
-{
-    Q_D(QmlDebugConnection);
-    if (!d->gotHello) {
-        QPacket pack(d->currentDataStreamVersion, d->protocol->read());
-        QString name;
-
-        pack >> name;
-
-        bool validHello = false;
-        if (name == clientId) {
-            int op = -1;
-            pack >> op;
-            if (op == 0) {
-                int version = -1;
-                pack >> version;
-                if (version == protocolVersion) {
-                    QStringList pluginNames;
-                    QList<float> pluginVersions;
-                    pack >> pluginNames;
-                    if (!pack.atEnd())
-                        pack >> pluginVersions;
-
-                    const int pluginNamesSize = pluginNames.size();
-                    const int pluginVersionsSize = pluginVersions.size();
-                    for (int i = 0; i < pluginNamesSize; ++i) {
-                        float pluginVersion = 1.0;
-                        if (i < pluginVersionsSize)
-                            pluginVersion = pluginVersions.at(i);
-                        d->serverPlugins.insert(pluginNames.at(i), pluginVersion);
-                    }
-
-                    if (!pack.atEnd()) {
-                        pack >> d->currentDataStreamVersion;
-                        if (d->currentDataStreamVersion > d->maximumDataStreamVersion)
-                            qWarning() << "Server returned invalid data stream version!";
-                    }
-                    validHello = true;
-                }
-            }
-        }
-
-        if (!validHello) {
-            qWarning("QML Debug Client: Invalid hello message");
-            close();
-            return;
-        }
-        d->gotHello = true;
-
-        QHash<QString, QmlDebugClient *>::Iterator iter = d->plugins.begin();
-        for (; iter != d->plugins.end(); ++iter) {
-            QmlDebugClient::State newState = QmlDebugClient::Unavailable;
-            if (d->serverPlugins.contains(iter.key()))
-                newState = QmlDebugClient::Enabled;
-            iter.value()->stateChanged(newState);
-        }
-        emit connected();
-    }
-
-    while (d->protocol && d->protocol->packetsAvailable()) {
-        QPacket pack(d->currentDataStreamVersion, d->protocol->read());
-        QString name;
-        pack >> name;
-
-        if (name == clientId) {
-            int op = -1;
-            pack >> op;
-
-            if (op == 1) {
-                // Service Discovery
-                QHash<QString, float> oldServerPlugins = d->serverPlugins;
-                d->serverPlugins.clear();
-
-                QStringList pluginNames;
-                QList<float> pluginVersions;
-                pack >> pluginNames;
-                if (!pack.atEnd())
-                    pack >> pluginVersions;
-
-                const int pluginNamesSize = pluginNames.size();
-                const int pluginVersionsSize = pluginVersions.size();
-                for (int i = 0; i < pluginNamesSize; ++i) {
-                    float pluginVersion = 1.0;
-                    if (i < pluginVersionsSize)
-                        pluginVersion = pluginVersions.at(i);
-                    d->serverPlugins.insert(pluginNames.at(i), pluginVersion);
-                }
-
-                QHash<QString, QmlDebugClient *>::Iterator iter = d->plugins.begin();
-                for (; iter != d->plugins.end(); ++iter) {
-                    const QString pluginName = iter.key();
-                    QmlDebugClient::State newState = QmlDebugClient::Unavailable;
-                    if (d->serverPlugins.contains(pluginName))
-                        newState = QmlDebugClient::Enabled;
-
-                    if (oldServerPlugins.contains(pluginName)
-                            != d->serverPlugins.contains(pluginName)) {
-                        iter.value()->stateChanged(newState);
-                    }
-                }
-            } else {
-                qWarning() << "QML Debug Client: Unknown control message id" << op;
-            }
-        } else {
-            QHash<QString, QmlDebugClient *>::Iterator iter = d->plugins.find(name);
-            if (iter == d->plugins.end()) {
-                qWarning() << "QML Debug Client: Message received for missing plugin" << name;
-            } else {
-                QmlDebugClient *client = *iter;
-                QByteArray message;
-                while (!pack.atEnd()) {
-                    pack >> message;
-                    client->messageReceived(message);
-                }
-            }
-        }
-    }
-}
-
-QmlDebugConnection::QmlDebugConnection(QObject *parent)
-    : QObject(parent), d_ptr(new QmlDebugConnectionPrivate)
-{
-}
-
-QmlDebugConnection::~QmlDebugConnection()
-{
-    socketDisconnected();
-}
-
-bool QmlDebugConnection::isConnected() const
-{
-    Q_D(const QmlDebugConnection);
-    // gotHello can only be set if the connection is open.
-    return d->gotHello;
-}
-
-bool QmlDebugConnection::isConnecting() const
-{
-    Q_D(const QmlDebugConnection);
-    return !d->gotHello && d->device;
-}
-
-void QmlDebugConnection::close()
-{
-    Q_D(QmlDebugConnection);
-    if (d->device && d->device->isOpen())
-        d->device->close(); // will trigger disconnected() at some point.
-}
-
-QmlDebugClient *QmlDebugConnection::client(const QString &name) const
-{
-    Q_D(const QmlDebugConnection);
-    return d->plugins.value(name, 0);
-}
-
-bool QmlDebugConnection::addClient(const QString &name, QmlDebugClient *client)
-{
-    Q_D(QmlDebugConnection);
-    if (d->plugins.contains(name))
-        return false;
-    d->plugins.insert(name, client);
-    d->advertisePlugins();
-    return true;
-}
-
-bool QmlDebugConnection::removeClient(const QString &name)
-{
-    Q_D(QmlDebugConnection);
-    if (!d->plugins.contains(name))
-        return false;
-    d->plugins.remove(name);
-    d->advertisePlugins();
-    return true;
-}
-
-float QmlDebugConnection::serviceVersion(const QString &serviceName) const
-{
-    Q_D(const QmlDebugConnection);
-    return d->serverPlugins.value(serviceName, -1);
-}
-
-bool QmlDebugConnection::sendMessage(const QString &name, const QByteArray &message)
-{
-    Q_D(QmlDebugConnection);
-    if (!d->gotHello || !d->serverPlugins.contains(name))
-        return false;
-
-    QPacket pack(d->currentDataStreamVersion);
-    pack << name << message;
-    d->protocol->send(pack.data());
-    d->flush();
-    return true;
-}
-
-void QmlDebugConnectionPrivate::flush()
-{
-    if (QAbstractSocket *socket = qobject_cast<QAbstractSocket *>(device))
-        socket->flush();
-    else if (QLocalSocket *socket = qobject_cast<QLocalSocket *>(device))
-        socket->flush();
-}
-
-void QmlDebugConnection::connectToHost(const QString &hostName, quint16 port)
-{
-    Q_D(QmlDebugConnection);
-    socketDisconnected();
-    QTcpSocket *socket = new QTcpSocket(this);
-    socket->setProxy(QNetworkProxy::NoProxy);
-    d->device = socket;
-    d->protocol = new QPacketProtocol(socket, this);
-    QObject::connect(d->protocol, &QPacketProtocol::readyRead,
-                     this, &QmlDebugConnection::protocolReadyRead);
-    connect(socket, &QAbstractSocket::stateChanged,
-            this, [this](QAbstractSocket::SocketState state) {
-        emit logStateChange(socketStateToString(state));
-    });
-
-    connect(socket, static_cast<void (QTcpSocket::*)(QAbstractSocket::SocketError)>
-            (&QAbstractSocket::error), this, [this](QAbstractSocket::SocketError error) {
-        emit logError(socketErrorToString(error));
-        socketDisconnected();
-    });
-    connect(socket, &QAbstractSocket::connected, this, &QmlDebugConnection::socketConnected);
-    connect(socket, &QAbstractSocket::disconnected, this, &QmlDebugConnection::socketDisconnected);
-    socket->connectToHost(hostName.isEmpty() ? QString("localhost") : hostName, port);
-}
-
-void QmlDebugConnection::startLocalServer(const QString &fileName)
-{
-    Q_D(QmlDebugConnection);
-    if (d->gotHello)
-        close();
-    if (d->server)
-        d->server->deleteLater();
-    d->server = new QLocalServer(this);
-    // QueuedConnection so that waitForNewConnection() returns true.
-    connect(d->server, &QLocalServer::newConnection,
-            this, &QmlDebugConnection::newConnection, Qt::QueuedConnection);
-    if (!d->server->listen(fileName))
-        emit connectionFailed();
-}
-
-void QmlDebugConnection::newConnection()
-{
-    Q_D(QmlDebugConnection);
-    delete d->device;
-    QLocalSocket *socket = d->server->nextPendingConnection();
-    d->server->close();
-    d->device = socket;
-    delete d->protocol;
-    d->protocol = new QPacketProtocol(socket, this);
-    QObject::connect(d->protocol, &QPacketProtocol::readyRead,
-                     this, &QmlDebugConnection::protocolReadyRead);
-
-    connect(socket, &QLocalSocket::disconnected, this, &QmlDebugConnection::socketDisconnected);
-
-    connect(socket, static_cast<void (QLocalSocket::*)(QLocalSocket::LocalSocketError)>
-            (&QLocalSocket::error), this, [this](QLocalSocket::LocalSocketError error) {
-        emit logError(socketErrorToString(static_cast<QAbstractSocket::SocketError>(error)));
-        socketDisconnected();
-    });
-
-    connect(socket, &QLocalSocket::stateChanged,
-            this, [this](QLocalSocket::LocalSocketState state) {
-        logStateChange(socketStateToString(static_cast<QAbstractSocket::SocketState>(state)));
-    });
-
-    socketConnected();
-}
-
-int QmlDebugConnection::currentDataStreamVersion() const
-{
-    Q_D(const QmlDebugConnection);
-    return d->currentDataStreamVersion;
-}
-
-void QmlDebugConnection::setMaximumDataStreamVersion(int maximumVersion)
-{
-    Q_D(QmlDebugConnection);
-    d->maximumDataStreamVersion = maximumVersion;
-}
-
-QAbstractSocket::SocketState QmlDebugConnection::socketState() const
-{
-    Q_D(const QmlDebugConnection);
-    if (QAbstractSocket *socket = qobject_cast<QAbstractSocket *>(d->device))
-        return socket->state();
-    else if (QLocalSocket *socket = qobject_cast<QLocalSocket *>(d->device))
-        return static_cast<QAbstractSocket::SocketState>(socket->state());
-    else
-        return QAbstractSocket::UnconnectedState;
-}
-
 QmlDebugClientPrivate::QmlDebugClientPrivate()
 {
 }
@@ -497,7 +107,8 @@ QmlDebugConnection *QmlDebugClient::connection() const
 int QmlDebugClient::dataStreamVersion() const
 {
     Q_D(const QmlDebugClient);
-    return (d->connection ? d->connection->currentDataStreamVersion() : minimumDataStreamVersion);
+    return (d->connection ? d->connection->currentDataStreamVersion()
+                          : QmlDebugConnection::minimumDataStreamVersion());
 }
 
 void QmlDebugClient::sendMessage(const QByteArray &message)
diff --git a/src/libs/qmldebug/qmldebugclient.h b/src/libs/qmldebug/qmldebugclient.h
index b39ec5f3db..fb5421d43d 100644
--- a/src/libs/qmldebug/qmldebugclient.h
+++ b/src/libs/qmldebug/qmldebugclient.h
@@ -32,52 +32,7 @@
 
 namespace QmlDebug {
 
-class QmlDebugClient;
-class QmlDebugConnectionPrivate;
-class QMLDEBUG_EXPORT QmlDebugConnection : public QObject
-{
-    Q_OBJECT
-    Q_DISABLE_COPY(QmlDebugConnection)
-    Q_DECLARE_PRIVATE(QmlDebugConnection)
-public:
-    QmlDebugConnection(QObject * = 0);
-    ~QmlDebugConnection();
-
-    void connectToHost(const QString &hostName, quint16 port);
-    void startLocalServer(const QString &fileName);
-    QAbstractSocket::SocketState socketState() const;
-
-    int currentDataStreamVersion() const;
-    void setMaximumDataStreamVersion(int maximumVersion);
-
-    bool isConnected() const;
-    bool isConnecting() const;
-    void close();
-
-    QmlDebugClient *client(const QString &name) const;
-    bool addClient(const QString &name, QmlDebugClient *client);
-    bool removeClient(const QString &name);
-
-    float serviceVersion(const QString &serviceName) const;
-    bool sendMessage(const QString &name, const QByteArray &message);
-
-signals:
-    void connected();
-    void disconnected();
-    void connectionFailed();
-
-    void logError(const QString &error);
-    void logStateChange(const QString &state);
-
-private:
-    void newConnection();
-    void socketConnected();
-    void socketDisconnected();
-    void protocolReadyRead();
-
-    QScopedPointer<QmlDebugConnectionPrivate> d_ptr;
-};
-
+class QmlDebugConnection;
 class QmlDebugClientPrivate;
 class QMLDEBUG_EXPORT QmlDebugClient : public QObject
 {
diff --git a/src/libs/qmldebug/qmldebugconnection.cpp b/src/libs/qmldebug/qmldebugconnection.cpp
new file mode 100644
index 0000000000..996896444e
--- /dev/null
+++ b/src/libs/qmldebug/qmldebugconnection.cpp
@@ -0,0 +1,431 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 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 "qmldebugconnection.h"
+#include "qmldebugclient.h"
+#include "qpacketprotocol.h"
+
+#include <utils/temporaryfile.h>
+
+#include <QLocalServer>
+#include <QLocalSocket>
+#include <QNetworkProxy>
+#include <QTcpServer>
+#include <QTcpSocket>
+
+namespace QmlDebug {
+
+const int protocolVersion = 1;
+
+const QString serverId = QLatin1String("QDeclarativeDebugServer");
+const QString clientId = QLatin1String("QDeclarativeDebugClient");
+
+class QmlDebugConnectionPrivate
+{
+public:
+    QmlDebugConnectionPrivate();
+    QPacketProtocol *protocol;
+    QLocalServer *server;
+    QIODevice *device; // Currently a QTcpSocket or a QLocalSocket
+
+    bool gotHello;
+    QHash <QString, float> serverPlugins;
+    QHash<QString, QmlDebugClient *> plugins;
+
+    int currentDataStreamVersion;
+    int maximumDataStreamVersion;
+
+    void advertisePlugins();
+    void flush();
+};
+
+static QString socketStateToString(QAbstractSocket::SocketState state)
+{
+    QString stateString;
+    QDebug(&stateString) << state;
+    return QmlDebugConnection::tr("Socket state changed to %1").arg(stateString);
+}
+
+static QString socketErrorToString(QAbstractSocket::SocketError error)
+{
+    QString errorString;
+    QDebug(&errorString) << error;
+    return QmlDebugConnection::tr("Error: %1").arg(errorString);
+}
+
+QmlDebugConnectionPrivate::QmlDebugConnectionPrivate() :
+    protocol(0), server(0), device(0), gotHello(false),
+    currentDataStreamVersion(QmlDebugConnection::minimumDataStreamVersion()),
+    maximumDataStreamVersion(QDataStream::Qt_DefaultCompiledVersion)
+{
+}
+
+void QmlDebugConnectionPrivate::advertisePlugins()
+{
+    if (!gotHello)
+        return;
+
+    QPacket pack(currentDataStreamVersion);
+    pack << serverId << 1 << plugins.keys();
+    protocol->send(pack.data());
+    flush();
+}
+
+void QmlDebugConnection::socketConnected()
+{
+    Q_D(QmlDebugConnection);
+    QPacket pack(d->currentDataStreamVersion);
+    pack << serverId << 0 << protocolVersion << d->plugins.keys() << d->maximumDataStreamVersion
+         << true; // We accept multiple messages per packet
+    d->protocol->send(pack.data());
+    d->flush();
+}
+
+void QmlDebugConnection::socketDisconnected()
+{
+    Q_D(QmlDebugConnection);
+    if (d->gotHello) {
+        d->gotHello = false;
+        QHash<QString, QmlDebugClient*>::iterator iter = d->plugins.begin();
+        for (; iter != d->plugins.end(); ++iter)
+            iter.value()->stateChanged(QmlDebugClient::NotConnected);
+        emit disconnected();
+    } else if (d->device) {
+        emit connectionFailed();
+    }
+    if (d->protocol) {
+        d->protocol->disconnect();
+        d->protocol->deleteLater();
+        d->protocol = 0;
+    }
+    if (d->device) {
+        // Don't allow any "connected()" or "disconnected()" signals to be triggered anymore.
+        // As the protocol is gone this would lead to crashes.
+        d->device->disconnect();
+        // Don't immediately delete it as it may do some cleanup on returning from a signal.
+        d->device->deleteLater();
+        d->device = 0;
+    }
+}
+
+void QmlDebugConnection::protocolReadyRead()
+{
+    Q_D(QmlDebugConnection);
+    if (!d->gotHello) {
+        QPacket pack(d->currentDataStreamVersion, d->protocol->read());
+        QString name;
+
+        pack >> name;
+
+        bool validHello = false;
+        if (name == clientId) {
+            int op = -1;
+            pack >> op;
+            if (op == 0) {
+                int version = -1;
+                pack >> version;
+                if (version == protocolVersion) {
+                    QStringList pluginNames;
+                    QList<float> pluginVersions;
+                    pack >> pluginNames;
+                    if (!pack.atEnd())
+                        pack >> pluginVersions;
+
+                    const int pluginNamesSize = pluginNames.size();
+                    const int pluginVersionsSize = pluginVersions.size();
+                    for (int i = 0; i < pluginNamesSize; ++i) {
+                        float pluginVersion = 1.0;
+                        if (i < pluginVersionsSize)
+                            pluginVersion = pluginVersions.at(i);
+                        d->serverPlugins.insert(pluginNames.at(i), pluginVersion);
+                    }
+
+                    if (!pack.atEnd()) {
+                        pack >> d->currentDataStreamVersion;
+                        if (d->currentDataStreamVersion > d->maximumDataStreamVersion)
+                            qWarning() << "Server returned invalid data stream version!";
+                    }
+                    validHello = true;
+                }
+            }
+        }
+
+        if (!validHello) {
+            qWarning("QML Debug Client: Invalid hello message");
+            close();
+            return;
+        }
+        d->gotHello = true;
+
+        QHash<QString, QmlDebugClient *>::Iterator iter = d->plugins.begin();
+        for (; iter != d->plugins.end(); ++iter) {
+            QmlDebugClient::State newState = QmlDebugClient::Unavailable;
+            if (d->serverPlugins.contains(iter.key()))
+                newState = QmlDebugClient::Enabled;
+            iter.value()->stateChanged(newState);
+        }
+        emit connected();
+    }
+
+    while (d->protocol && d->protocol->packetsAvailable()) {
+        QPacket pack(d->currentDataStreamVersion, d->protocol->read());
+        QString name;
+        pack >> name;
+
+        if (name == clientId) {
+            int op = -1;
+            pack >> op;
+
+            if (op == 1) {
+                // Service Discovery
+                QHash<QString, float> oldServerPlugins = d->serverPlugins;
+                d->serverPlugins.clear();
+
+                QStringList pluginNames;
+                QList<float> pluginVersions;
+                pack >> pluginNames;
+                if (!pack.atEnd())
+                    pack >> pluginVersions;
+
+                const int pluginNamesSize = pluginNames.size();
+                const int pluginVersionsSize = pluginVersions.size();
+                for (int i = 0; i < pluginNamesSize; ++i) {
+                    float pluginVersion = 1.0;
+                    if (i < pluginVersionsSize)
+                        pluginVersion = pluginVersions.at(i);
+                    d->serverPlugins.insert(pluginNames.at(i), pluginVersion);
+                }
+
+                QHash<QString, QmlDebugClient *>::Iterator iter = d->plugins.begin();
+                for (; iter != d->plugins.end(); ++iter) {
+                    const QString pluginName = iter.key();
+                    QmlDebugClient::State newState = QmlDebugClient::Unavailable;
+                    if (d->serverPlugins.contains(pluginName))
+                        newState = QmlDebugClient::Enabled;
+
+                    if (oldServerPlugins.contains(pluginName)
+                            != d->serverPlugins.contains(pluginName)) {
+                        iter.value()->stateChanged(newState);
+                    }
+                }
+            } else {
+                qWarning() << "QML Debug Client: Unknown control message id" << op;
+            }
+        } else {
+            QHash<QString, QmlDebugClient *>::Iterator iter = d->plugins.find(name);
+            if (iter == d->plugins.end()) {
+                qWarning() << "QML Debug Client: Message received for missing plugin" << name;
+            } else {
+                QmlDebugClient *client = *iter;
+                QByteArray message;
+                while (!pack.atEnd()) {
+                    pack >> message;
+                    client->messageReceived(message);
+                }
+            }
+        }
+    }
+}
+
+QmlDebugConnection::QmlDebugConnection(QObject *parent)
+    : QObject(parent), d_ptr(new QmlDebugConnectionPrivate)
+{
+}
+
+QmlDebugConnection::~QmlDebugConnection()
+{
+    socketDisconnected();
+}
+
+bool QmlDebugConnection::isConnected() const
+{
+    Q_D(const QmlDebugConnection);
+    // gotHello can only be set if the connection is open.
+    return d->gotHello;
+}
+
+bool QmlDebugConnection::isConnecting() const
+{
+    Q_D(const QmlDebugConnection);
+    return !d->gotHello && d->device;
+}
+
+void QmlDebugConnection::close()
+{
+    Q_D(QmlDebugConnection);
+    if (d->device && d->device->isOpen())
+        d->device->close(); // will trigger disconnected() at some point.
+}
+
+QmlDebugClient *QmlDebugConnection::client(const QString &name) const
+{
+    Q_D(const QmlDebugConnection);
+    return d->plugins.value(name, 0);
+}
+
+bool QmlDebugConnection::addClient(const QString &name, QmlDebugClient *client)
+{
+    Q_D(QmlDebugConnection);
+    if (d->plugins.contains(name))
+        return false;
+    d->plugins.insert(name, client);
+    d->advertisePlugins();
+    return true;
+}
+
+bool QmlDebugConnection::removeClient(const QString &name)
+{
+    Q_D(QmlDebugConnection);
+    if (!d->plugins.contains(name))
+        return false;
+    d->plugins.remove(name);
+    d->advertisePlugins();
+    return true;
+}
+
+float QmlDebugConnection::serviceVersion(const QString &serviceName) const
+{
+    Q_D(const QmlDebugConnection);
+    return d->serverPlugins.value(serviceName, -1);
+}
+
+bool QmlDebugConnection::sendMessage(const QString &name, const QByteArray &message)
+{
+    Q_D(QmlDebugConnection);
+    if (!d->gotHello || !d->serverPlugins.contains(name))
+        return false;
+
+    QPacket pack(d->currentDataStreamVersion);
+    pack << name << message;
+    d->protocol->send(pack.data());
+    d->flush();
+    return true;
+}
+
+int QmlDebugConnection::minimumDataStreamVersion()
+{
+    return QDataStream::Qt_4_7;
+}
+
+void QmlDebugConnectionPrivate::flush()
+{
+    if (QAbstractSocket *socket = qobject_cast<QAbstractSocket *>(device))
+        socket->flush();
+    else if (QLocalSocket *socket = qobject_cast<QLocalSocket *>(device))
+        socket->flush();
+}
+
+void QmlDebugConnection::connectToHost(const QString &hostName, quint16 port)
+{
+    Q_D(QmlDebugConnection);
+    socketDisconnected();
+    QTcpSocket *socket = new QTcpSocket(this);
+    socket->setProxy(QNetworkProxy::NoProxy);
+    d->device = socket;
+    d->protocol = new QPacketProtocol(socket, this);
+    QObject::connect(d->protocol, &QPacketProtocol::readyRead,
+                     this, &QmlDebugConnection::protocolReadyRead);
+    connect(socket, &QAbstractSocket::stateChanged,
+            this, [this](QAbstractSocket::SocketState state) {
+        emit logStateChange(socketStateToString(state));
+    });
+
+    connect(socket, static_cast<void (QTcpSocket::*)(QAbstractSocket::SocketError)>
+            (&QAbstractSocket::error), this, [this](QAbstractSocket::SocketError error) {
+        emit logError(socketErrorToString(error));
+        socketDisconnected();
+    });
+    connect(socket, &QAbstractSocket::connected, this, &QmlDebugConnection::socketConnected);
+    connect(socket, &QAbstractSocket::disconnected, this, &QmlDebugConnection::socketDisconnected);
+    socket->connectToHost(hostName.isEmpty() ? QString("localhost") : hostName, port);
+}
+
+void QmlDebugConnection::startLocalServer(const QString &fileName)
+{
+    Q_D(QmlDebugConnection);
+    if (d->gotHello)
+        close();
+    if (d->server)
+        d->server->deleteLater();
+    d->server = new QLocalServer(this);
+    // QueuedConnection so that waitForNewConnection() returns true.
+    connect(d->server, &QLocalServer::newConnection,
+            this, &QmlDebugConnection::newConnection, Qt::QueuedConnection);
+    if (!d->server->listen(fileName))
+        emit connectionFailed();
+}
+
+void QmlDebugConnection::newConnection()
+{
+    Q_D(QmlDebugConnection);
+    delete d->device;
+    QLocalSocket *socket = d->server->nextPendingConnection();
+    d->server->close();
+    d->device = socket;
+    delete d->protocol;
+    d->protocol = new QPacketProtocol(socket, this);
+    QObject::connect(d->protocol, &QPacketProtocol::readyRead,
+                     this, &QmlDebugConnection::protocolReadyRead);
+
+    connect(socket, &QLocalSocket::disconnected, this, &QmlDebugConnection::socketDisconnected);
+
+    connect(socket, static_cast<void (QLocalSocket::*)(QLocalSocket::LocalSocketError)>
+            (&QLocalSocket::error), this, [this](QLocalSocket::LocalSocketError error) {
+        emit logError(socketErrorToString(static_cast<QAbstractSocket::SocketError>(error)));
+        socketDisconnected();
+    });
+
+    connect(socket, &QLocalSocket::stateChanged,
+            this, [this](QLocalSocket::LocalSocketState state) {
+        logStateChange(socketStateToString(static_cast<QAbstractSocket::SocketState>(state)));
+    });
+
+    socketConnected();
+}
+
+int QmlDebugConnection::currentDataStreamVersion() const
+{
+    Q_D(const QmlDebugConnection);
+    return d->currentDataStreamVersion;
+}
+
+void QmlDebugConnection::setMaximumDataStreamVersion(int maximumVersion)
+{
+    Q_D(QmlDebugConnection);
+    d->maximumDataStreamVersion = maximumVersion;
+}
+
+QAbstractSocket::SocketState QmlDebugConnection::socketState() const
+{
+    Q_D(const QmlDebugConnection);
+    if (QAbstractSocket *socket = qobject_cast<QAbstractSocket *>(d->device))
+        return socket->state();
+    else if (QLocalSocket *socket = qobject_cast<QLocalSocket *>(d->device))
+        return static_cast<QAbstractSocket::SocketState>(socket->state());
+    else
+        return QAbstractSocket::UnconnectedState;
+}
+
+} // namespace QmlDebug
diff --git a/src/libs/qmldebug/qmldebugconnection.h b/src/libs/qmldebug/qmldebugconnection.h
new file mode 100644
index 0000000000..d217291751
--- /dev/null
+++ b/src/libs/qmldebug/qmldebugconnection.h
@@ -0,0 +1,84 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 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.
+**
+****************************************************************************/
+
+#pragma once
+
+#include "qmldebug_global.h"
+
+#include <QObject>
+#include <QUrl>
+#include <QAbstractSocket>
+
+namespace QmlDebug {
+
+class QmlDebugClient;
+class QmlDebugConnectionPrivate;
+class QMLDEBUG_EXPORT QmlDebugConnection : public QObject
+{
+    Q_OBJECT
+    Q_DISABLE_COPY(QmlDebugConnection)
+    Q_DECLARE_PRIVATE(QmlDebugConnection)
+public:
+    QmlDebugConnection(QObject * = 0);
+    ~QmlDebugConnection();
+
+    void connectToHost(const QString &hostName, quint16 port);
+    void startLocalServer(const QString &fileName);
+    QAbstractSocket::SocketState socketState() const;
+
+    int currentDataStreamVersion() const;
+    void setMaximumDataStreamVersion(int maximumVersion);
+
+    bool isConnected() const;
+    bool isConnecting() const;
+    void close();
+
+    QmlDebugClient *client(const QString &name) const;
+    bool addClient(const QString &name, QmlDebugClient *client);
+    bool removeClient(const QString &name);
+
+    float serviceVersion(const QString &serviceName) const;
+    bool sendMessage(const QString &name, const QByteArray &message);
+
+    static int minimumDataStreamVersion();
+
+signals:
+    void connected();
+    void disconnected();
+    void connectionFailed();
+
+    void logError(const QString &error);
+    void logStateChange(const QString &state);
+
+private:
+    void newConnection();
+    void socketConnected();
+    void socketDisconnected();
+    void protocolReadyRead();
+
+    QScopedPointer<QmlDebugConnectionPrivate> d_ptr;
+};
+
+} // namespace QmlDebug
diff --git a/src/libs/qmldebug/qmltoolsclient.cpp b/src/libs/qmldebug/qmltoolsclient.cpp
index e882f0733b..1f22e36b74 100644
--- a/src/libs/qmldebug/qmltoolsclient.cpp
+++ b/src/libs/qmldebug/qmltoolsclient.cpp
@@ -24,6 +24,7 @@
 ****************************************************************************/
 
 #include "qmltoolsclient.h"
+#include "qmldebugconnection.h"
 #include <qmldebug/qpacketprotocol.h>
 #include <QStringList>