CppEditor: Avoid premature calls to recalculateSemanticInfoNow

Now recalculateSemanticInfoNow is called only once instead of three
times when a new editor is opened/created.

Change-Id: Ife84fc9ca90cdbf2a417123e6a2b9e1e068dfdc4
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>

src/plugins/cppeditor/cppeditor.cpp

@@ -1132,7 +1132,10 @@ void CPPEditorWidget::updateUses()
 {
     if (editorRevision() != m_highlightRevision)
         m_highlighter.cancel();
-    m_updateUsesTimer->start();
+
+    // Block premature semantic info calculation when editor is created.
+    if (m_modelManager->cppEditorSupport(editor())->initialized())
+        m_updateUsesTimer->start();
 }
 
 void CPPEditorWidget::updateUsesNow()

src/plugins/cpptools/cpptoolseditorsupport.cpp

@@ -175,6 +175,11 @@ void CppEditorSupport::setExtraDiagnostics(const QString &key,
     emit diagnosticsChanged();
 }
 
+bool CppEditorSupport::initialized()
+{
+    return m_initialized;
+}
+
 SemanticInfo CppEditorSupport::recalculateSemanticInfo(bool emitSignalWhenFinished)
 {
     m_futureSemanticInfo.cancel();
@@ -186,6 +191,11 @@ SemanticInfo CppEditorSupport::recalculateSemanticInfo(bool emitSignalWhenFinish
 
 void CppEditorSupport::recalculateSemanticInfoDetached(bool force)
 {
+    // Block premature calculation caused by CppEditorPlugin::currentEditorChanged
+    // when the editor is created.
+    if (!m_initialized)
+        return;
+
     m_futureSemanticInfo.cancel();
     SemanticInfo::Source source = currentSource(force);
     m_futureSemanticInfo = QtConcurrent::run<CppEditorSupport, void>(

src/plugins/cpptools/cpptoolseditorsupport.h

@@ -98,12 +98,17 @@ public:
     void setExtraDiagnostics(const QString &key,
                              const QList<CPlusPlus::Document::DiagnosticMessage> &messages);
 
+    /// True after the document was parsed/updated for the first time
+    /// and the first semantic info calculation was started.
+    bool initialized();
+
     /// Retrieve the semantic info, which will get recalculated on the current
     /// thread if it is outdate.
     SemanticInfo recalculateSemanticInfo(bool emitSignalWhenFinished = true);
 
-    /// Recalculates the semantic info in a future, and will emit the semanticInfoUpdated() signal
-    /// when finished.
+    /// Recalculates the semantic info in a future, and will emit the
+    /// semanticInfoUpdated() signal when finished.
+    /// Requires that initialized() is true.
     /// \param force do not check if the old semantic info is still valid
     void recalculateSemanticInfoDetached(bool force = false);