C++: Release more documents.

- fix memory leak in find-usages
- do not retain snapshot in search history
- when an editor is invisible for more than 2 minutes, release the
  backing snapshot

Retaining snapshots will retain their documents, and if done for too
long, the memory consumption might grow. This is especially the case
when switching to a different kit (Qt version): in that case, the new
versions of headers will be indexed, while the old ones stay around.

Task-number: QTCREATORBUG-5583
Task-number: QTCREATORBUG-7645
Task-number: QTCREATORBUG-9842

Change-Id: I045eda1565e0a3fa702baeffaab9c12662f90289
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>

src/plugins/cppeditor/cppfunctiondecldeflink.cpp

@@ -60,13 +60,12 @@ using namespace Utils;
 FunctionDeclDefLinkFinder::FunctionDeclDefLinkFinder(QObject *parent)
     : QObject(parent)
 {
-    connect(&m_watcher, SIGNAL(finished()),
-            this, SLOT(onFutureDone()));
 }
 
 void FunctionDeclDefLinkFinder::onFutureDone()
 {
-    QSharedPointer<FunctionDeclDefLink> link = m_watcher.result();
+    QSharedPointer<FunctionDeclDefLink> link = m_watcher->result();
+    m_watcher.reset();
     if (link) {
         link->linkSelection = m_scannedSelection;
         link->nameSelection = m_nameSelection;
@@ -256,7 +255,9 @@ void FunctionDeclDefLinkFinder::startFindLinkAt(
     result->sourceFunctionDeclarator = funcDecl;
 
     // handle the rest in a thread
-    m_watcher.setFuture(QtConcurrent::run(&findLinkHelper, result, refactoringChanges));
+    m_watcher.reset(new QFutureWatcher<QSharedPointer<FunctionDeclDefLink> >());
+    connect(m_watcher.data(), SIGNAL(finished()), this, SLOT(onFutureDone()));
+    m_watcher->setFuture(QtConcurrent::run(&findLinkHelper, result, refactoringChanges));
 }
 
 FunctionDeclDefLink::FunctionDeclDefLink()
@@ -270,10 +271,6 @@ FunctionDeclDefLink::FunctionDeclDefLink()
     targetFunctionDeclarator = 0;
 }
 
-FunctionDeclDefLink::~FunctionDeclDefLink()
-{
-}
-
 bool FunctionDeclDefLink::isValid() const
 {
     return !linkSelection.isNull();

src/plugins/cppeditor/cppfunctiondecldeflink.h

@@ -67,7 +67,7 @@ private slots:
 private:
     QTextCursor m_scannedSelection;
     QTextCursor m_nameSelection;
-    QFutureWatcher<QSharedPointer<FunctionDeclDefLink> > m_watcher;
+    QScopedPointer<QFutureWatcher<QSharedPointer<FunctionDeclDefLink> > > m_watcher;
 };
 
 class FunctionDeclDefLink
@@ -75,8 +75,6 @@ class FunctionDeclDefLink
     Q_DECLARE_TR_FUNCTIONS(CppEditor::Internal::FunctionDeclDefLink)
     Q_DISABLE_COPY(FunctionDeclDefLink)
 public:
-    ~FunctionDeclDefLink();
-
     class Marker {};
 
     bool isValid() const;

src/plugins/cpptools/cppfindreferences.cpp

@@ -247,8 +247,9 @@ public:
 
 CppFindReferences::CppFindReferences(CppModelManagerInterface *modelManager)
     : QObject(modelManager),
-      _modelManager(modelManager)
+      m_modelManager(modelManager)
 {
+    connect(modelManager, SIGNAL(globalSnapshotChanged()), this, SLOT(flushDependencyTable()));
 }
 
 CppFindReferences::~CppFindReferences()
@@ -365,7 +366,7 @@ void CppFindReferences::findAll_helper(Find::SearchResult *search, CPlusPlus::Sy
             this, SLOT(openEditor(Find::SearchResultItem)));
 
     Find::SearchResultWindow::instance()->popup(IOutputPane::ModeSwitch | IOutputPane::WithFocus);
-    const CppModelManagerInterface::WorkingCopy workingCopy = _modelManager->workingCopy();
+    const CppModelManagerInterface::WorkingCopy workingCopy = m_modelManager->workingCopy();
     QFuture<Usage> result;
     result = QtConcurrent::run(&find_helper, workingCopy, context, this, symbol);
     createWatcher(result, search);
@@ -382,7 +383,7 @@ void CppFindReferences::onReplaceButtonClicked(const QString &text,
 {
     const QStringList fileNames = TextEditor::BaseFileFind::replaceAll(text, items, preserveCase);
     if (!fileNames.isEmpty()) {
-        _modelManager->updateSourceFiles(fileNames);
+        m_modelManager->updateSourceFiles(fileNames);
         Find::SearchResultWindow::instance()->hide();
     }
 }
@@ -451,7 +452,7 @@ CPlusPlus::Symbol *CppFindReferences::findSymbol(const CppFindReferencesParamete
 
     Document::Ptr newSymbolDocument = snapshot.document(symbolFile);
     // document is not parsed and has no bindings yet, do it
-    QByteArray source = getSource(newSymbolDocument->fileName(), _modelManager->workingCopy());
+    QByteArray source = getSource(newSymbolDocument->fileName(), m_modelManager->workingCopy());
     Document::Ptr doc =
             snapshot.preprocessedDocument(source, newSymbolDocument->fileName());
     doc->check();
@@ -492,6 +493,7 @@ void CppFindReferences::searchFinished()
     if (search)
         search->finishSearch(watcher->isCanceled());
     m_watchers.remove(watcher);
+    watcher->deleteLater();
 }
 
 void CppFindReferences::cancel()
@@ -651,8 +653,8 @@ void CppFindReferences::findMacroUses(const Macro &macro, const QString &replace
     connect(search, SIGNAL(cancelled()), this, SLOT(cancel()));
     connect(search, SIGNAL(paused(bool)), this, SLOT(setPaused(bool)));
 
-    const Snapshot snapshot = _modelManager->snapshot();
-    const CppModelManagerInterface::WorkingCopy workingCopy = _modelManager->workingCopy();
+    const Snapshot snapshot = m_modelManager->snapshot();
+    const CppModelManagerInterface::WorkingCopy workingCopy = m_modelManager->workingCopy();
 
     // add the macro definition itself
     {
@@ -691,6 +693,13 @@ DependencyTable CppFindReferences::updateDependencyTable(CPlusPlus::Snapshot sna
     return newDeps;
 }
 
+void CppFindReferences::flushDependencyTable()
+{
+    QMutexLocker locker(&m_depsLock);
+    Q_UNUSED(locker);
+    m_deps = DependencyTable();
+}
+
 DependencyTable CppFindReferences::dependencyTable() const
 {
     QMutexLocker locker(&m_depsLock);

src/plugins/cpptools/cppfindreferences.h

@@ -78,7 +78,10 @@ public:
 
     CPlusPlus::DependencyTable updateDependencyTable(CPlusPlus::Snapshot snapshot);
 
-private Q_SLOTS:
+public slots:
+    void flushDependencyTable();
+
+private slots:
     void displayResults(int first, int last);
     void searchFinished();
     void cancel();
@@ -101,7 +104,7 @@ private:
                     const CPlusPlus::Snapshot &snapshot, CPlusPlus::LookupContext *context);
 
 private:
-    QPointer<CppModelManagerInterface> _modelManager;
+    QPointer<CppModelManagerInterface> m_modelManager;
     QMap<QFutureWatcher<CPlusPlus::Usage> *, QPointer<Find::SearchResult> > m_watchers;
 
     mutable QMutex m_depsLock;

src/plugins/cpptools/cppmodelmanager.cpp

@@ -234,6 +234,11 @@ CppModelManager::CppModelManager(QObject *parent)
     , m_indexingSupporter(0)
     , m_enableGC(true)
 {
+    connect(this, SIGNAL(documentUpdated(CPlusPlus::Document::Ptr)),
+            this, SIGNAL(globalSnapshotChanged()));
+    connect(this, SIGNAL(aboutToRemoveFiles(QStringList)),
+            this, SIGNAL(globalSnapshotChanged()));
+
     m_findReferences = new CppFindReferences(this);
     m_indexerEnabled = qgetenv("QTCREATOR_NO_CODE_INDEXER").isNull();
 

src/plugins/cpptools/cppmodelmanagerinterface.h

@@ -279,6 +279,8 @@ signals:
     /// Other classes can use this to get notified when the \c ProjectExplorer has updated the parts.
     void projectPartsUpdated(ProjectExplorer::Project *project);
 
+    void globalSnapshotChanged();
+
 public slots:
     // Documented in source file.
     virtual QFuture<void> updateSourceFiles(const QStringList &sourceFiles,

src/plugins/cpptools/cppsnapshotupdater.cpp

@@ -41,6 +41,7 @@ SnapshotUpdater::SnapshotUpdater(const QString &fileInEditor)
     , m_fileInEditor(fileInEditor)
     , m_editorDefinesChangedSinceLastUpdate(false)
     , m_usePrecompiledHeaders(false)
+    , m_forceSnapshotInvalidation(false)
 {
 }
 
@@ -62,6 +63,11 @@ void SnapshotUpdater::update(CppModelManager::WorkingCopy workingCopy)
 
     updateProjectPart();
 
+    if (m_forceSnapshotInvalidation) {
+        invalidateSnapshot = true;
+        m_forceSnapshotInvalidation = false;
+    }
+
     if (m_projectPart) {
         configFile += m_projectPart->defines;
         includePaths = m_projectPart->includePaths;
@@ -186,6 +192,14 @@ void SnapshotUpdater::update(CppModelManager::WorkingCopy workingCopy)
     }
 }
 
+void SnapshotUpdater::releaseSnapshot()
+{
+    QMutexLocker locker(&m_mutex);
+    m_snapshot = Snapshot();
+    m_deps = DependencyTable();
+    m_forceSnapshotInvalidation = true;
+}
+
 Document::Ptr SnapshotUpdater::document() const
 {
     QMutexLocker locker(&m_mutex);

src/plugins/cpptools/cppsnapshotupdater.h

@@ -52,6 +52,7 @@ public:
     { return m_fileInEditor; }
 
     void update(CppModelManagerInterface::WorkingCopy workingCopy);
+    void releaseSnapshot();
 
     CPlusPlus::Document::Ptr document() const;
     CPlusPlus::Snapshot snapshot() const;
@@ -81,6 +82,7 @@ private:
     CPlusPlus::Snapshot m_snapshot;
     CPlusPlus::DependencyTable m_deps;
     bool m_usePrecompiledHeaders;
+    bool m_forceSnapshotInvalidation;
 };
 
 } // namespace CppTools

src/plugins/cpptools/cpptoolseditorsupport.cpp

@@ -115,6 +115,7 @@ CppEditorSupport::CppEditorSupport(CppModelManager *modelManager, BaseTextEditor
     , m_textEditor(textEditor)
     , m_updateDocumentInterval(UpdateDocumentDefaultInterval)
     , m_revision(0)
+    , m_editorVisible(textEditor->widget()->isVisible())
     , m_cachedContentsEditorRevision(-1)
     , m_fileIsBeingReloaded(false)
     , m_initialized(false)
@@ -152,6 +153,13 @@ CppEditorSupport::CppEditorSupport(CppModelManager *modelManager, BaseTextEditor
     connect(m_textEditor->document(), SIGNAL(reloadFinished(bool)),
             this, SLOT(onReloadFinished()));
 
+    connect(Core::EditorManager::instance(), SIGNAL(currentEditorChanged(Core::IEditor *)),
+            this, SLOT(onCurrentEditorChanged()));
+    m_editorGCTimer = new QTimer(this);
+    m_editorGCTimer->setSingleShot(true);
+    m_editorGCTimer->setInterval(EditorHiddenGCTimeout);
+    connect(m_editorGCTimer, SIGNAL(timeout()), this, SLOT(releaseResources()));
+
     updateDocument();
 }
 
@@ -460,6 +468,30 @@ void CppEditorSupport::updateEditorNow()
     editorWidget->setIfdefedOutBlocks(m_editorUpdates.ifdefedOutBlocks);
 }
 
+void CppEditorSupport::onCurrentEditorChanged()
+{
+    bool editorVisible = m_textEditor->widget()->isVisible();
+
+    if (m_editorVisible != editorVisible) {
+        m_editorVisible = editorVisible;
+        if (editorVisible) {
+            m_editorGCTimer->stop();
+            QMutexLocker locker(&m_lastSemanticInfoLock);
+            if (!m_lastSemanticInfo.doc)
+                updateDocumentNow();
+        } else {
+            m_editorGCTimer->start(EditorHiddenGCTimeout);
+        }
+    }
+}
+
+void CppEditorSupport::releaseResources()
+{
+    snapshotUpdater()->releaseSnapshot();
+    QMutexLocker semanticLocker(&m_lastSemanticInfoLock);
+    m_lastSemanticInfo = SemanticInfo();
+}
+
 SemanticInfo::Source CppEditorSupport::currentSource(bool force)
 {
     int line = 0, column = 0;

src/plugins/cpptools/cpptoolseditorsupport.h

@@ -148,6 +148,9 @@ private slots:
     void updateEditor();
     void updateEditorNow();
 
+    void onCurrentEditorChanged();
+    void releaseResources();
+
 private:
     struct EditorUpdates {
         EditorUpdates()
@@ -160,7 +163,8 @@ private:
 
     enum {
         UpdateDocumentDefaultInterval = 150,
-        UpdateEditorInterval = 300
+        UpdateEditorInterval = 300,
+        EditorHiddenGCTimeout = 2 * 60 * 1000 // 2 minutes
     };
 
 private:
@@ -178,6 +182,9 @@ private:
     unsigned m_revision;
     QFuture<void> m_documentParser;
 
+    QTimer *m_editorGCTimer;
+    bool m_editorVisible;
+
     // content caching
     mutable QMutex m_cachedContentsLock;
     mutable QByteArray m_cachedContents;