ui/base/cocoa/tracking_area.h

   1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef UI_BASE_COCOA_TRACKING_AREA_H_
   6 #define UI_BASE_COCOA_TRACKING_AREA_H_
   7
   8 #import <AppKit/AppKit.h>
   9
  10 #include "base/mac/scoped_nsobject.h"
  11 #include "ui/base/ui_base_export.h"
  12
  13 @class CrTrackingAreaOwnerProxy;
  14
  15 // The CrTrackingArea can be used in place of an NSTrackingArea to shut off
  16 // messaging to the |owner| at a specific point in time.
  17 UI_BASE_EXPORT
  18 @interface CrTrackingArea : NSTrackingArea {
  19  @private
  20   base::scoped_nsobject<CrTrackingAreaOwnerProxy> ownerProxy_;
  21 }
  22
  23 // Designated initializer. Forwards all arguments to the superclass, but wraps
  24 // |owner| in a proxy object.
  25 - (instancetype)initWithRect:(NSRect)rect
  26            options:(NSTrackingAreaOptions)options
  27              owner:(id)owner
  28           userInfo:(NSDictionary*)userInfo;
  29
  30 // Prevents any future messages from being delivered to the |owner|.
  31 - (void)clearOwner;
  32
  33 // Watches |window| for its NSWindowWillCloseNotification and calls
  34 // |-clearOwner| when the notification is observed.
  35 - (void)clearOwnerWhenWindowWillClose:(NSWindow*)window;
  36
  37 @end
  38
  39 // Scoper //////////////////////////////////////////////////////////////////////
  40
  41 namespace ui {
  42
  43 // Use an instance of this class to call |-clearOwner| on the |tracking_area_|
  44 // when this goes out of scope.
  45 class UI_BASE_EXPORT ScopedCrTrackingArea {
  46  public:
  47   // Takes ownership of |tracking_area| without retaining it.
  48   explicit ScopedCrTrackingArea(CrTrackingArea* tracking_area = nil);
  49   ~ScopedCrTrackingArea();
  50
  51   // This will call |scoped_nsobject<>::reset()| to take ownership of the new
  52   // tracking area.  Note that -clearOwner is NOT called on the existing
  53   // tracking area.
  54   void reset(CrTrackingArea* tracking_area = nil);
  55
  56   CrTrackingArea* get() const;
  57
  58  private:
  59   base::scoped_nsobject<CrTrackingArea> tracking_area_;
  60   DISALLOW_COPY_AND_ASSIGN(ScopedCrTrackingArea);
  61 };
  62
  63 }  // namespace ui
  64
  65 #endif  // UI_BASE_COCOA_TRACKING_AREA_H_