Clang: Stop sending data to backend on disconnect

This addresses

    SOFT ASSERT made fatal: "m_connection.isConnected()" in file
      src/plugins/clangcodemodel/clangbackendipcintegration.cpp, line 230

I could not reproduce the issue locally, so I'm leaving the soft asserts
untouched for now.

Change-Id: If1d55ba7bc7e2d1ac20ad992c6d0d43ceb0f5d73
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/libs/clangbackendipc/connectionclient.cpp

@@ -51,6 +51,7 @@ ConnectionClient::ConnectionClient()
 
     connectLocalSocketError();
     connectLocalSocketConnected();
+    connectLocalSocketDisconnected();
 }
 
 void ConnectionClient::startProcessAndConnectToServerAsynchronously()
@@ -230,6 +231,14 @@ void ConnectionClient::connectLocalSocketConnected()
             &ConnectionClient::resetProcessIsStarting);
 }
 
+void ConnectionClient::connectLocalSocketDisconnected()
+{
+    connect(&localSocket,
+            &QLocalSocket::disconnected,
+            this,
+            &ConnectionClient::disconnectedFromLocalSocket);
+}
+
 void ConnectionClient::finishProcess()
 {
     finishProcess(std::move(process_));

src/libs/clangbackendipc/connectionclient.h

@@ -76,6 +76,7 @@ public:
 
 signals:
     void connectedToLocalSocket();
+    void disconnectedFromLocalSocket();
     void processFinished();
 
 protected:
@@ -102,6 +103,7 @@ private:
     void printStandardError();
 
     void connectLocalSocketConnected();
+    void connectLocalSocketDisconnected();
     void connectProcessFinished(QProcess *process) const;
     void connectProcessStarted(QProcess *process) const;
     void disconnectProcessFinished(QProcess *process) const;

src/plugins/clangcodemodel/clangbackendipcintegration.cpp

@@ -313,11 +313,16 @@ IpcCommunicator::IpcCommunicator()
     connect(Core::EditorManager::instance(), &Core::EditorManager::editorAboutToClose,
             this, &IpcCommunicator::onEditorAboutToClose);
     connect(Core::ICore::instance(), &Core::ICore::coreAboutToClose,
-            this, &IpcCommunicator::onCoreAboutToClose);
+            this, &IpcCommunicator::setupDummySender);
 
     initializeBackend();
 }
 
+IpcCommunicator::~IpcCommunicator()
+{
+    disconnect(&m_connection, 0, this, 0);
+}
+
 void IpcCommunicator::initializeBackend()
 {
     const QString clangBackEndProcessPath = backendProcessPath();
@@ -329,6 +334,8 @@ void IpcCommunicator::initializeBackend()
 
     connect(&m_connection, &ConnectionClient::connectedToLocalSocket,
             this, &IpcCommunicator::onConnectedToBackend);
+    connect(&m_connection, &ConnectionClient::disconnectedFromLocalSocket,
+            this, &IpcCommunicator::setupDummySender);
 
     m_connection.startProcessAndConnectToServerAsynchronously();
 }
@@ -633,7 +640,7 @@ void IpcCommunicator::onEditorAboutToClose(Core::IEditor *editor)
         m_ipcReceiver.deleteProcessorsOfEditorWidget(textEditor->editorWidget());
 }
 
-void IpcCommunicator::onCoreAboutToClose()
+void IpcCommunicator::setupDummySender()
 {
     m_ipcSender.reset(new DummyIpcSender);
 }

src/plugins/clangcodemodel/clangbackendipcintegration.h

@@ -116,6 +116,7 @@ public:
 
 public:
     IpcCommunicator();
+    ~IpcCommunicator();
 
     void registerTranslationUnitsForEditor(const FileContainers &fileContainers);
     void updateTranslationUnitsForEditor(const FileContainers &fileContainers);
@@ -164,9 +165,11 @@ private:
     void registerVisibleCppEditorDocumentAndMarkInvisibleDirty();
     void registerCurrentCodeModelUiHeaders();
 
+    void setupDummySender();
+
     void onConnectedToBackend();
+    void onDisconnectedFromBackend();
     void onEditorAboutToClose(Core::IEditor *editor);
-    void onCoreAboutToClose();
 
     void updateTranslationUnitVisiblity(const Utf8String &currentEditorFilePath,
                                         const Utf8StringVector &visibleEditorsFilePaths);