Locator: Cancel running search when closing

When closing e.g. a separate window with a locator search running, we
don't need the search to continue. Save resources by cancelling it.

Change-Id: I889b9cd163a9cc79045fb0eda9797856c489bd39
Reviewed-by: Jarek Kobus <jaroslaw.kobus@qt.io>

src/plugins/coreplugin/locator/locatorwidget.cpp

@@ -623,6 +623,13 @@ LocatorWidget::LocatorWidget(Locator *locator) :
     updateFilterList();
 }
 
+LocatorWidget::~LocatorWidget()
+{
+    // no need to completely finish a running search, cancel it
+    if (m_entriesWatcher->future().isRunning())
+        m_entriesWatcher->future().cancel();
+}
+
 void LocatorWidget::updatePlaceholderText(Command *command)
 {
     QTC_ASSERT(command, return);

src/plugins/coreplugin/locator/locatorwidget.h

@@ -57,6 +57,7 @@ class LocatorWidget
 
 public:
     explicit LocatorWidget(Locator *locator);
+    ~LocatorWidget() override;
 
     void showText(const QString &text, int selectionStart = -1, int selectionLength = 0);
     QString currentText() const;