Clang: Fix reloading documents

Fix the following use case:
 * Open foo.h
 * Open foo.cpp
 * Change both files externally (e.g. git checkout) e.g. by adding a
   function (declaration + definition)
 * Confirm the reload dialog in Qt Creator
 * The added function in foo.cpp gets a diagnostic that it's out of line
   although foo.h is also reloaded.

TextDocument::contentsChangedWithPosition() is also emitted during a
reload. However, the revision of the document at that point is not yet
updated. This led to an out-dated copy of the unsaved files in the clang
backend.

Change-Id: I70580d32bb7a34dc43356dc05019cc18addf950e
Reviewed-by: Marco Bubke <marco.bubke@theqtcompany.com>

src/plugins/clangcodemodel/clangmodelmanagersupport.cpp

@@ -116,25 +116,43 @@ void ModelManagerSupportClang::onCurrentEditorChanged(Core::IEditor *newCurrent)
 void ModelManagerSupportClang::connectTextDocumentToTranslationUnit(TextEditor::TextDocument *textDocument)
 {
     // Handle externally changed documents
+    connect(textDocument, &Core::IDocument::aboutToReload,
+            this, &ModelManagerSupportClang::onCppDocumentAboutToReloadOnTranslationUnit,
+            Qt::UniqueConnection);
     connect(textDocument, &Core::IDocument::reloadFinished,
             this, &ModelManagerSupportClang::onCppDocumentReloadFinishedOnTranslationUnit,
             Qt::UniqueConnection);
 
     // Handle changes from e.g. refactoring actions
-    connect(textDocument, &TextEditor::TextDocument::contentsChangedWithPosition,
+    connectToTextDocumentContentsChangedForTranslationUnit(textDocument);
-            this, &ModelManagerSupportClang::onCppDocumentContentsChangedOnTranslationUnit,
-            Qt::UniqueConnection);
 }
 
 void ModelManagerSupportClang::connectTextDocumentToUnsavedFiles(TextEditor::TextDocument *textDocument)
 {
     // Handle externally changed documents
+    connect(textDocument, &Core::IDocument::aboutToReload,
+            this, &ModelManagerSupportClang::onCppDocumentAboutToReloadOnUnsavedFile,
+            Qt::UniqueConnection);
     connect(textDocument, &Core::IDocument::reloadFinished,
             this, &ModelManagerSupportClang::onCppDocumentReloadFinishedOnUnsavedFile,
             Qt::UniqueConnection);
 
     // Handle changes from e.g. refactoring actions
-    connect(textDocument, &TextEditor::TextDocument::contentsChanged,
+    connectToTextDocumentContentsChangedForUnsavedFile(textDocument);
+}
+
+void ModelManagerSupportClang::connectToTextDocumentContentsChangedForTranslationUnit(
+        TextEditor::TextDocument *textDocument)
+{
+    connect(textDocument, &TextEditor::TextDocument::contentsChangedWithPosition,
+            this, &ModelManagerSupportClang::onCppDocumentContentsChangedOnTranslationUnit,
+            Qt::UniqueConnection);
+}
+
+void ModelManagerSupportClang::connectToTextDocumentContentsChangedForUnsavedFile(
+        TextEditor::TextDocument *textDocument)
+{
+    connect(textDocument, &TextEditor::TextDocument::contentsChangedWithPosition,
             this, &ModelManagerSupportClang::onCppDocumentContentsChangedOnUnsavedFile,
             Qt::UniqueConnection);
 }
@@ -168,11 +186,19 @@ void ModelManagerSupportClang::onEditorOpened(Core::IEditor *editor)
     }
 }
 
+void ModelManagerSupportClang::onCppDocumentAboutToReloadOnTranslationUnit()
+{
+    TextEditor::TextDocument *textDocument = qobject_cast<TextEditor::TextDocument *>(sender());
+    disconnect(textDocument, &TextEditor::TextDocument::contentsChangedWithPosition,
+               this, &ModelManagerSupportClang::onCppDocumentContentsChangedOnTranslationUnit);
+}
+
 void ModelManagerSupportClang::onCppDocumentReloadFinishedOnTranslationUnit(bool success)
 {
     if (success) {
-        Core::IDocument *document = qobject_cast<Core::IDocument *>(sender());
+        TextEditor::TextDocument *textDocument = qobject_cast<TextEditor::TextDocument *>(sender());
-        m_ipcCommunicator.requestDiagnostics(document);
+        connectToTextDocumentContentsChangedForTranslationUnit(textDocument);
+        m_ipcCommunicator.requestDiagnostics(textDocument);
     }
 }
 
@@ -187,11 +213,19 @@ void ModelManagerSupportClang::onCppDocumentContentsChangedOnTranslationUnit(int
     m_ipcCommunicator.updateTranslationUnitIfNotCurrentDocument(document);
 }
 
+void ModelManagerSupportClang::onCppDocumentAboutToReloadOnUnsavedFile()
+{
+    TextEditor::TextDocument *textDocument = qobject_cast<TextEditor::TextDocument *>(sender());
+    disconnect(textDocument, &TextEditor::TextDocument::contentsChangedWithPosition,
+               this, &ModelManagerSupportClang::onCppDocumentContentsChangedOnUnsavedFile);
+}
+
 void ModelManagerSupportClang::onCppDocumentReloadFinishedOnUnsavedFile(bool success)
 {
     if (success) {
-        Core::IDocument *document = qobject_cast<Core::IDocument *>(sender());
+        TextEditor::TextDocument *textDocument = qobject_cast<TextEditor::TextDocument *>(sender());
-        m_ipcCommunicator.updateUnsavedFile(document);
+        connectToTextDocumentContentsChangedForUnsavedFile(textDocument);
+        m_ipcCommunicator.updateUnsavedFile(textDocument);
     }
 }
 

src/plugins/clangcodemodel/clangmodelmanagersupport.h

@@ -72,10 +72,12 @@ public:
 private:
     void onEditorOpened(Core::IEditor *editor);
     void onCurrentEditorChanged(Core::IEditor *newCurrent);
+    void onCppDocumentAboutToReloadOnTranslationUnit();
     void onCppDocumentReloadFinishedOnTranslationUnit(bool success);
     void onCppDocumentContentsChangedOnTranslationUnit(int position,
                                                        int charsRemoved,
                                                        int charsAdded);
+    void onCppDocumentAboutToReloadOnUnsavedFile();
     void onCppDocumentReloadFinishedOnUnsavedFile(bool success);
     void onCppDocumentContentsChangedOnUnsavedFile();
 
@@ -93,6 +95,9 @@ private:
 
     void connectTextDocumentToTranslationUnit(TextEditor::TextDocument *textDocument);
     void connectTextDocumentToUnsavedFiles(TextEditor::TextDocument *textDocument);
+    void connectToTextDocumentContentsChangedForTranslationUnit(
+            TextEditor::TextDocument *textDocument);
+    void connectToTextDocumentContentsChangedForUnsavedFile(TextEditor::TextDocument *textDocument);
     void connectToWidgetsMarkContextMenuRequested(QWidget *editorWidget);
 
 private: