VCS: Abort previous command for the same editor

It is very common to have output from a previous (longer) command appear
instead of the newly created one.

For example: Open a log. Check "Show Diff" and immediately uncheck it.
If this is done fast enough (or with a high Log Count limit) the output
with the diff will appear instead of the normal log.

Change-Id: Ie64cc4a383a261f5328a4d0486eec93f73766679
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>

src/plugins/vcsbase/vcsbaseeditor.cpp

@@ -32,6 +32,7 @@
 #include "baseannotationhighlighter.h"
 #include "vcsbaseplugin.h"
 #include "vcsbaseeditorparameterwidget.h"
+#include "command.h"
 
 #include <coreplugin/icore.h>
 #include <coreplugin/vcsmanager.h>
@@ -575,6 +576,7 @@ public:
     VcsBaseEditorParameterWidget *m_configurationWidget;
     bool m_mouseDragging;
     QList<AbstractTextCursorHandler *> m_textCursorHandlers;
+    QPointer<Command> m_command;
 
 private:
     QComboBox *m_entriesComboBox;
@@ -1350,6 +1352,13 @@ VcsBaseEditorParameterWidget *VcsBaseEditorWidget::configurationWidget() const
     return d->m_configurationWidget;
 }
 
+void VcsBaseEditorWidget::setCommand(Command *command)
+{
+    if (d->m_command)
+        d->m_command->abort();
+    d->m_command = command;
+}
+
 // Find the complete file from a diff relative specification.
 QString VcsBaseEditorWidget::findDiffFile(const QString &f) const
 {