C++: release more futures.

The CPPEditorWidget retained two futures, as did the attached future
watchers retained them too. Together, each future and the watcher held
on to a complete snapshot that would only get released when another
future was set. This could result into retaining old snapshots in
editors that were invisible/unused for long.

Change-Id: I1133e857c620437b4a69b9dad468f6bd458304b8
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>

2 files changed, 5 insertions, 3 deletions

diff --git a/src/plugins/cpptools/cpptoolseditorsupport.cpp b/src/plugins/cpptools/cpptoolseditorsupport.cpp
index 2638a127ce..6a31f98f85 100644
--- a/src/plugins/cpptools/cpptoolseditorsupport.cpp
+++ b/src/plugins/cpptools/cpptoolseditorsupport.cpp
@@ -390,7 +390,7 @@ void CppEditorSupport::startHighlighting()
 
         m_highlighter = m_highlightingSupport->highlightingFuture(doc, snapshot);
         m_lastHighlightRevision = revision;
-        emit highlighterStarted(&m_highlighter, m_lastHighlightRevision);
+        emit highlighterStarted(m_highlighter, m_lastHighlightRevision);
     } else {
         const unsigned revision = currentSource(false).revision;
         if (m_lastHighlightRevision == revision)
@@ -400,7 +400,7 @@ void CppEditorSupport::startHighlighting()
         static const Document::Ptr dummyDoc;
         static const Snapshot dummySnapshot;
         m_highlighter = m_highlightingSupport->highlightingFuture(dummyDoc, dummySnapshot);
-        emit highlighterStarted(&m_highlighter, m_lastHighlightRevision);
+        emit highlighterStarted(m_highlighter, m_lastHighlightRevision);
     }
 }
 
@@ -500,6 +500,8 @@ void CppEditorSupport::onCurrentEditorChanged()
 
 void CppEditorSupport::releaseResources()
 {
+    m_highlighter.cancel();
+    m_highlighter = QFuture<TextEditor::HighlightingResult>();
     snapshotUpdater()->releaseSnapshot();
     QMutexLocker semanticLocker(&m_lastSemanticInfoLock);
     m_lastSemanticInfo = SemanticInfo();
diff --git a/src/plugins/cpptools/cpptoolseditorsupport.h b/src/plugins/cpptools/cpptoolseditorsupport.h
index f9ba876256..1d6179e5d8 100644
--- a/src/plugins/cpptools/cpptoolseditorsupport.h
+++ b/src/plugins/cpptools/cpptoolseditorsupport.h
@@ -132,7 +132,7 @@ signals:
     void documentUpdated();
     void diagnosticsChanged();
     void semanticInfoUpdated(CppTools::SemanticInfo);
-    void highlighterStarted(QFuture<TextEditor::HighlightingResult> *, unsigned revision);
+    void highlighterStarted(QFuture<TextEditor::HighlightingResult>, unsigned revision);
 
 private slots:
     void onMimeTypeChanged();