Guard: Make it possible to lock/unlock manually

Use it in some KitAspectWidget subclasses.

Change-Id: Ie683d5af6a44d0042456418af729a3d718396803
Reviewed-by: hjk <hjk@qt.io>

src/libs/utils/guard.cpp

@@ -97,6 +97,17 @@ bool Guard::isLocked() const
     return m_lockCount;
 }
 
+void Guard::lock()
+{
+    ++m_lockCount;
+}
+
+void Guard::unlock()
+{
+    QTC_CHECK(m_lockCount > 0);
+    --m_lockCount;
+}
+
 GuardLocker::GuardLocker(Guard &guard)
     : m_guard(guard)
 {

src/libs/utils/guard.h

@@ -38,6 +38,12 @@ public:
     Guard();
     ~Guard();
     bool isLocked() const;
+
+    // Prefer using GuardLocker when possible. These two methods are provided only for cases
+    // when locking and unlocking are done in separate methods, so that GuardLocker can't be
+    // used.
+    void lock();
+    void unlock();
 private:
     int m_lockCount = 0;
     friend class GuardLocker;

src/plugins/projectexplorer/kitinformation.cpp

@@ -946,23 +946,23 @@ private:
     void modelAboutToReset()
     {
         m_selectedId = m_model->deviceId(m_comboBox->currentIndex());
-        m_ignoreChange = true;
+        m_ignoreChanges.lock();
     }
 
     void modelReset()
     {
         m_comboBox->setCurrentIndex(m_model->indexForId(m_selectedId));
-        m_ignoreChange = false;
+        m_ignoreChanges.unlock();
     }
 
     void currentDeviceChanged()
     {
-        if (m_ignoreChange)
+        if (m_ignoreChanges.isLocked())
             return;
         DeviceKitAspect::setDeviceId(m_kit, m_model->deviceId(m_comboBox->currentIndex()));
     }
 
-    bool m_ignoreChange = false;
+    Guard m_ignoreChanges;
     QComboBox *m_comboBox;
     QWidget *m_manageButton;
     DeviceManagerModel *m_model;
@@ -1218,23 +1218,23 @@ private:
     void modelAboutToReset()
     {
         m_selectedId = m_model->deviceId(m_comboBox->currentIndex());
-        m_ignoreChange = true;
+        m_ignoreChanges.lock();
     }
 
     void modelReset()
     {
         m_comboBox->setCurrentIndex(m_model->indexForId(m_selectedId));
-        m_ignoreChange = false;
+        m_ignoreChanges.unlock();
     }
 
     void currentDeviceChanged()
     {
-        if (m_ignoreChange)
+        if (m_ignoreChanges.isLocked())
             return;
         BuildDeviceKitAspect::setDeviceId(m_kit, m_model->deviceId(m_comboBox->currentIndex()));
     }
 
-    bool m_ignoreChange = false;
+    Guard m_ignoreChanges;
     QComboBox *m_comboBox;
     QWidget *m_manageButton;
     DeviceManagerModel *m_model;