C++: handle file type changes for choosing highlighters.

If the file type (mime type) of an editor changes, it might need a
different kind of highlighter/highlighting-support.

Change-Id: I470dbf69e71856c9593d201416c4d4bd2958aaec
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>

src/plugins/cppeditor/cppeditor.cpp

@@ -1166,7 +1166,7 @@ void CPPEditorWidget::finishHighlightSymbolUsages()
     if (editorRevision() != m_highlightRevision)
         return; // outdated
 
-    else if (m_highlighter.isCanceled())
+    if (m_highlighter.isCanceled())
         return; // aborted
 
     TextEditor::SyntaxHighlighter *highlighter = baseTextDocument()->syntaxHighlighter();
@@ -1174,11 +1174,6 @@ void CPPEditorWidget::finishHighlightSymbolUsages()
 
     TextEditor::SemanticHighlighter::clearExtraAdditionalFormatsUntilEnd(
                 highlighter, m_highlighter);
-
-    if (m_modelManager)
-        m_modelManager->setExtraDiagnostics(m_lastSemanticInfo.doc->fileName(),
-                                            QLatin1String("CppEditor.SemanticsDiagnostics"),
-                                            m_lastSemanticInfo.doc->diagnosticMessages());
 }
 
 void CPPEditorWidget::switchDeclarationDefinition(bool inNextSplit)

src/plugins/cpptools/cpptoolseditorsupport.cpp

@@ -115,16 +115,10 @@ CppEditorSupport::CppEditorSupport(CppModelManager *modelManager, BaseTextEditor
     , m_cachedContentsEditorRevision(-1)
     , m_initialized(false)
     , m_lastHighlightRevision(0)
-    , m_highlightingSupport(modelManager->highlightingSupport(textEditor))
 {
     connect(m_modelManager, SIGNAL(documentUpdated(CPlusPlus::Document::Ptr)),
             this, SLOT(onDocumentUpdated(CPlusPlus::Document::Ptr)));
 
-    if (m_highlightingSupport && m_highlightingSupport->requiresSemanticInfo()) {
-        connect(this, SIGNAL(semanticInfoUpdated(CppTools::SemanticInfo)),
-                this, SLOT(startHighlighting()));
-    }
-
     m_updateDocumentTimer = new QTimer(this);
     m_updateDocumentTimer->setSingleShot(true);
     m_updateDocumentTimer->setInterval(m_updateDocumentInterval);
@@ -139,7 +133,8 @@ CppEditorSupport::CppEditorSupport(CppModelManager *modelManager, BaseTextEditor
     connect(m_textEditor, SIGNAL(contentsChanged()), this, SLOT(updateDocument()));
     connect(this, SIGNAL(diagnosticsChanged()), this, SLOT(onDiagnosticsChanged()));
 
-    updateDocument();
+    connect(m_textEditor->document(), SIGNAL(mimeTypeChanged()),
+            this, SLOT(onMimeTypeChanged()));
 }
 
 CppEditorSupport::~CppEditorSupport()
@@ -486,3 +481,19 @@ void CppEditorSupport::recalculateSemanticInfoDetached_helper(QFutureInterface<v
     TLDProc tldProc(future);
     recalculateSemanticInfoNow(source, true, &tldProc);
 }
+
+void CppEditorSupport::onMimeTypeChanged()
+{
+    m_highlighter.cancel();
+    m_highlighter.waitForFinished();
+
+    m_highlightingSupport.reset(m_modelManager->highlightingSupport(m_textEditor));
+
+    disconnect(this, SIGNAL(semanticInfoUpdated(CppTools::SemanticInfo)),
+               this, SLOT(startHighlighting()));
+    if (m_highlightingSupport && m_highlightingSupport->requiresSemanticInfo())
+        connect(this, SIGNAL(semanticInfoUpdated(CppTools::SemanticInfo)),
+                this, SLOT(startHighlighting()));
+
+    updateDocumentNow();
+}

src/plugins/cpptools/cpptoolseditorsupport.h

@@ -119,6 +119,8 @@ signals:
     void highlighterStarted(QFuture<TextEditor::HighlightingResult> *, unsigned revision);
 
 private slots:
+    void onMimeTypeChanged();
+
     void updateDocument();
     void updateDocumentNow();
 

src/plugins/texteditor/basetextdocument.cpp

@@ -113,7 +113,10 @@ QString BaseTextDocument::mimeType() const
 
 void BaseTextDocument::setMimeType(const QString &mt)
 {
-    d->m_mimeType = mt;
+    if (d->m_mimeType != mt) {
+        d->m_mimeType = mt;
+        emit mimeTypeChanged();
+    }
 }
 
 void BaseTextDocument::setTypingSettings(const TypingSettings &typingSettings)

src/plugins/texteditor/basetextdocument.h

@@ -105,6 +105,7 @@ public:
 
 signals:
     void titleChanged(QString title);
+    void mimeTypeChanged();
 
 private:
     void cleanWhitespace(QTextCursor &cursor, bool cleanIndentation, bool inEntireDocument);