Utils: Introduce GlobalFileChangeBlocker

Tracks application state, and signals when it is changed.

Supports forcing blocked state with reference counting.

Change-Id: Ic173d42446b1b08bd4a1e7c1acf38c68644d30b3
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@qt.io>
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/clangcodemodel/clangbackendcommunicator.cpp

@@ -48,6 +48,7 @@
 #include <clangsupport/filecontainer.h>
 #include <clangsupport/clangcodemodelservermessages.h>
 
+#include <utils/globalfilechangeblocker.h>
 #include <utils/qtcassert.h>
 
 #include <QDateTime>
@@ -104,6 +105,10 @@ BackendCommunicator::BackendCommunicator()
             this, &BackendCommunicator::onEditorAboutToClose);
     connect(Core::ICore::instance(), &Core::ICore::coreAboutToClose,
             this, &BackendCommunicator::setupDummySender);
+    auto globalFCB = ::Utils::GlobalFileChangeBlocker::instance();
+    m_postponeBackendJobs = globalFCB->isBlocked();
+    connect(globalFCB, &::Utils::GlobalFileChangeBlocker::stateChanged,
+            this, &BackendCommunicator::setBackendJobsPostponed);
 
     initializeBackend();
 }
@@ -210,14 +215,11 @@ bool BackendCommunicator::isNotWaitingForCompletion() const
 void BackendCommunicator::setBackendJobsPostponed(bool postponed)
 {
     if (postponed) {
-        if (!m_postponeBackendJobs)
-            documentVisibilityChanged(Utf8String(), {});
-        ++m_postponeBackendJobs;
+        documentVisibilityChanged(Utf8String(), {});
+        m_postponeBackendJobs = postponed;
     } else {
-        if (QTC_GUARD(m_postponeBackendJobs > 0))
-            --m_postponeBackendJobs;
-        if (!m_postponeBackendJobs)
-            documentVisibilityChanged();
+        m_postponeBackendJobs = postponed;
+        documentVisibilityChanged();
     }
 }
 

src/plugins/clangcodemodel/clangbackendcommunicator.h

@@ -136,7 +136,7 @@ private:
     QTimer m_backendStartTimeOut;
     QScopedPointer<ClangBackEnd::ClangCodeModelServerInterface> m_sender;
     int m_connectedCount = 0;
-    int m_postponeBackendJobs = 1; // Initial application state is inactive, so no jobs should be run.
+    bool m_postponeBackendJobs = false;
 };
 
 } // namespace Internal

src/plugins/clangcodemodel/clangmodelmanagersupport.cpp

@@ -76,8 +76,6 @@ ClangModelManagerSupport::ClangModelManagerSupport()
     QTC_CHECK(!m_instance);
     m_instance = this;
 
-    QApplication::instance()->installEventFilter(this);
-
     CppTools::CppModelManager::instance()->setCurrentDocumentFilter(
                 std::make_unique<ClangCurrentDocumentFilter>());
 
@@ -141,11 +139,6 @@ std::unique_ptr<CppTools::AbstractOverviewModel> ClangModelManagerSupport::creat
     return std::make_unique<OverviewModel>();
 }
 
-void ClangModelManagerSupport::setBackendJobsPostponed(bool postponed)
-{
-    m_communicator.setBackendJobsPostponed(postponed);
-}
-
 CppTools::BaseEditorDocumentProcessor *ClangModelManagerSupport::createEditorDocumentProcessor(
         TextEditor::TextDocument *baseTextDocument)
 {
@@ -219,20 +212,6 @@ void ClangModelManagerSupport::connectToWidgetsMarkContextMenuRequested(QWidget
     }
 }
 
-bool ClangModelManagerSupport::eventFilter(QObject *obj, QEvent *e)
-{
-    if (obj == QApplication::instance() && e->type() == QEvent::ApplicationStateChange) {
-        switch (QApplication::applicationState()) {
-        case Qt::ApplicationInactive: setBackendJobsPostponed(true); break;
-        case Qt::ApplicationActive: setBackendJobsPostponed(false); break;
-        default:
-            QTC_CHECK(false && "Unexpected Qt::ApplicationState");
-        }
-    }
-
-    return false;
-}
-
 void ClangModelManagerSupport::onEditorOpened(Core::IEditor *editor)
 {
     QTC_ASSERT(editor, return);

src/plugins/clangcodemodel/clangmodelmanagersupport.h

@@ -72,7 +72,6 @@ public:
     CppTools::FollowSymbolInterface &followSymbolInterface() override;
     CppTools::RefactoringEngineInterface &refactoringEngineInterface() override;
     std::unique_ptr<CppTools::AbstractOverviewModel> createOverviewModel() override;
-    void setBackendJobsPostponed(bool postponed) override;
 
     BackendCommunicator &communicator();
     QString dummyUiHeaderOnDiskDirPath() const;
@@ -83,8 +82,6 @@ public:
     static ClangModelManagerSupport *instance();
 
 private:
-    bool eventFilter(QObject *obj, QEvent *e) override;
-
     void onEditorOpened(Core::IEditor *editor);
     void onEditorClosed(const QList<Core::IEditor *> &editors);
     void onCurrentEditorChanged(Core::IEditor *newCurrent);