CppTools: Do not hand over partly reloaded files to the code model

When a reloading operation was in progress, CppEditorSupport::contents()
could return a partly reloaded file to the code model leading to parse
errors and incomplete highlighting.

Fixed by checking if the file is currently being reloaded.

Task-number: QTCREATORBUG-9382

Change-Id: Iee97e10444763c0cbf481132afa4617c5cdbd15c
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>

src/plugins/cpptools/cpptoolseditorsupport.cpp

@@ -33,6 +33,7 @@
 
 #include <coreplugin/editormanager/editormanager.h>
 
+#include <utils/qtcassert.h>
 #include <utils/runextensions.h>
 
 #include <QList>
@@ -113,6 +114,7 @@ CppEditorSupport::CppEditorSupport(CppModelManager *modelManager, BaseTextEditor
     , m_updateDocumentInterval(UpdateDocumentDefaultInterval)
     , m_revision(0)
     , m_cachedContentsEditorRevision(-1)
+    , m_fileIsBeingReloaded(false)
     , m_initialized(false)
     , m_lastHighlightRevision(0)
     , m_highlightingSupport(modelManager->highlightingSupport(textEditor))
@@ -142,6 +144,11 @@ CppEditorSupport::CppEditorSupport(CppModelManager *modelManager, BaseTextEditor
     connect(m_textEditor->document(), SIGNAL(mimeTypeChanged()),
             this, SLOT(onMimeTypeChanged()));
 
+    connect(m_textEditor->document(), SIGNAL(aboutToReload()),
+            this, SLOT(onAboutToReload()));
+    connect(m_textEditor->document(), SIGNAL(reloadFinished(bool)),
+            this, SLOT(onReloadFinished()));
+
     updateDocument();
 }
 
@@ -162,7 +169,7 @@ QString CppEditorSupport::fileName() const
 QString CppEditorSupport::contents() const
 {
     const int editorRev = editorRevision();
-    if (m_cachedContentsEditorRevision != editorRev) {
+    if (m_cachedContentsEditorRevision != editorRev && !m_fileIsBeingReloaded) {
         m_cachedContentsEditorRevision = editorRev;
         m_cachedContents = m_textEditor->textDocument()->contents();
     }
@@ -233,9 +240,11 @@ void CppEditorSupport::updateDocumentNow()
     } else {
         m_updateDocumentTimer->stop();
 
-        if (m_highlightingSupport && !m_highlightingSupport->requiresSemanticInfo()) {
+        if (m_fileIsBeingReloaded)
+            return;
+
+        if (m_highlightingSupport && !m_highlightingSupport->requiresSemanticInfo())
             startHighlighting();
-        }
 
         const QStringList sourceFiles(m_textEditor->document()->fileName());
         m_documentParser = m_modelManager->updateSourceFiles(sourceFiles);
@@ -505,3 +514,16 @@ void CppEditorSupport::onMimeTypeChanged()
 
     updateDocumentNow();
 }
+
+void CppEditorSupport::onAboutToReload()
+{
+    QTC_CHECK(!m_fileIsBeingReloaded);
+    m_fileIsBeingReloaded = true;
+}
+
+void CppEditorSupport::onReloadFinished()
+{
+    QTC_CHECK(m_fileIsBeingReloaded);
+    m_fileIsBeingReloaded = false;
+    updateDocument();
+}

src/plugins/cpptools/cpptoolseditorsupport.h

@@ -121,6 +121,9 @@ signals:
 private slots:
     void onMimeTypeChanged();
 
+    void onAboutToReload();
+    void onReloadFinished();
+
     void updateDocument();
     void updateDocumentNow();
 
@@ -166,6 +169,7 @@ private:
     // content caching
     mutable QString m_cachedContents;
     mutable int m_cachedContentsEditorRevision;
+    bool m_fileIsBeingReloaded;
 
     QTimer *m_updateEditorTimer;
     EditorUpdates m_editorUpdates;