Git: Fix crash when returning to commit editor from diff

The crash happens on Linux/Xming. 2 subsequents calls to
slotRefreshCommitData occur, m_commitDataFetcher is released when the
first one is handled, and the second call dereferences NULL.

Change-Id: Ibc06fe5dd89b790ac84544f6842cbf345d118703
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>

src/plugins/git/gitsubmiteditor.cpp

@@ -229,9 +229,10 @@ void GitSubmitEditor::updateFileModel()
         m_firstUpdate = false;
         return;
     }
-    if (m_workingDirectory.isEmpty())
+    GitSubmitEditorWidget *w = submitEditorWidget();
+    if (w->updateInProgress() || m_workingDirectory.isEmpty())
         return;
-    submitEditorWidget()->setUpdateInProgress(true);
+    w->setUpdateInProgress(true);
     resetCommitDataFetcher();
     m_commitDataFetcher = new CommitDataFetcher(m_commitType, m_workingDirectory);
     connect(m_commitDataFetcher, SIGNAL(finished(bool)), this, SLOT(commitDataRetrieved(bool)));
@@ -244,10 +245,9 @@ void GitSubmitEditor::updateFileModel()
 void GitSubmitEditor::commitDataRetrieved(bool success)
 {
     GitSubmitEditorWidget *w = submitEditorWidget();
-    w->setUpdateInProgress(false);
     if (success) {
         setCommitData(m_commitDataFetcher->commitData());
-        submitEditorWidget()->refreshLog(m_workingDirectory);
+        w->refreshLog(m_workingDirectory);
         w->setEnabled(true);
     } else {
         // Nothing to commit left!
@@ -257,6 +257,7 @@ void GitSubmitEditor::commitDataRetrieved(bool success)
     }
     m_commitDataFetcher->deleteLater();
     m_commitDataFetcher = 0;
+    w->setUpdateInProgress(false);
 }
 
 GitSubmitEditorPanelData GitSubmitEditor::panelData() const

src/plugins/vcsbase/submiteditorwidget.cpp

@@ -583,6 +583,11 @@ void SubmitEditorWidget::setUpdateInProgress(bool value)
     updateSubmitAction();
 }
 
+bool SubmitEditorWidget::updateInProgress() const
+{
+    return d->m_updateInProgress;
+}
+
 QString SubmitEditorWidget::commitName() const
 {
     return tr("&Commit");

src/plugins/vcsbase/submiteditorwidget.h

@@ -105,6 +105,7 @@ public:
 
     virtual bool canSubmit() const;
     void setUpdateInProgress(bool value);
+    bool updateInProgress() const;
 
 signals:
     void diffSelected(const QList<int> &);