Fix typeahead cancellation in file panels.

- Add accessor to PoseView that reports whether the view is currently
  typeahead filtering.
- Use said accessor in the file panel's filter in order to detect whether
  to tell the latter to cancel filtering vs closing the panel.

Fixes #8140.

src/kits/tracker/FilePanelPriv.cpp

@@ -101,7 +101,7 @@ GetLinkFlavor(const Model *model, bool resolve = true)
 
 
 static filter_result
-key_down_filter(BMessage *message, BHandler **, BMessageFilter *filter)
+key_down_filter(BMessage *message, BHandler **handler, BMessageFilter *filter)
 {
 	TFilePanel *panel = dynamic_cast<TFilePanel *>(filter->Looper());
 	ASSERT(panel);
@@ -119,6 +119,8 @@ key_down_filter(BMessage *message, BHandler **, BMessageFilter *filter)
 	if (!modifier && key == B_ESCAPE) {
 		if (view->ActivePose())
 			view->CommitActivePose(false);
+		else if (view->IsFiltering())
+			filter->Looper()->PostMessage(B_CANCEL, *handler);
 		else
 			filter->Looper()->PostMessage(kCancelButton);
 		return B_SKIP_MESSAGE;

src/kits/tracker/PoseView.cpp

@@ -2413,7 +2413,7 @@ BPoseView::MessageReceived(BMessage *message)
 
 				if (PrimarySort() == attrHash)
 					attrHash = 0;
-					
+
 				SetPrimarySort(attrHash);
 				SetSecondarySort(0);
 				Cleanup(true);
@@ -9801,6 +9801,13 @@ BPoseView::StartFiltering()
 }
 
 
+bool
+BPoseView::IsFiltering() const
+{
+	return fFiltering;
+}
+
+
 void
 BPoseView::StopFiltering()
 {

src/kits/tracker/PoseView.h

@@ -402,6 +402,9 @@ class BPoseView : public BView {
 		void StartWatchDateFormatChange();
 		void StopWatchDateFormatChange();
 
+		// type ahead filtering
+		bool IsFiltering() const;
+
 		void UpdateDateColumns(BMessage *);
 		virtual void AdaptToVolumeChange(BMessage *);
 		virtual void AdaptToDesktopIntegrationChange(BMessage *);