xref: /external/chromium/chrome/browser/ui/cocoa/tracking_area.h

// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CHROME_BROWSER_UI_COCOA_TRACKING_AREA_H_
#define CHROME_BROWSER_UI_COCOA_TRACKING_AREA_H_

#import <AppKit/AppKit.h>

#include "base/memory/scoped_nsobject.h"

@class CrTrackingAreaOwnerProxy;

// The CrTrackingArea can be used in place of an NSTrackingArea to shut off
// messaging to the |owner| at a specific point in time.
@interface CrTrackingArea : NSTrackingArea {
 @private
  scoped_nsobject<CrTrackingAreaOwnerProxy> ownerProxy_;
}

// Designated initializer. Forwards all arguments to the superclass, but wraps
// |owner| in a proxy object.
//
// The |proxiedOwner:| paramater has been renamed due to an incompatiblity with
// the 10.5 SDK. Since that SDK version declares |-[NSTrackingArea's init...]|'s
// return type to be |NSTrackingArea*| rather than |id|, a more generalized type
// can't be returned by the subclass. Until the project switches to the 10.6 SDK
// (where Apple changed the return type to |id|), this ugly hack must exist.
// TODO(rsesek): Remove this when feasabile.
- (id)initWithRect:(NSRect)rect
           options:(NSTrackingAreaOptions)options
      proxiedOwner:(id)owner  // 10.5 SDK hack. Remove at some point.
          userInfo:(NSDictionary*)userInfo;

// Prevents any future messages from being delivered to the |owner|.
- (void)clearOwner;

// Watches |window| for its NSWindowWillCloseNotification and calls
// |-clearOwner| when the notification is observed.
- (void)clearOwnerWhenWindowWillClose:(NSWindow*)window;

@end

// Scoper //////////////////////////////////////////////////////////////////////

// Use an instance of this class to call |-clearOwner| on the |tracking_area_|
// when this goes out of scope.
class ScopedCrTrackingArea {
 public:
  // Takes ownership of |tracking_area| without retaining it.
  explicit ScopedCrTrackingArea(CrTrackingArea* tracking_area = nil);
  ~ScopedCrTrackingArea();

  // This will call |scoped_nsobject<>::reset()| to take ownership of the new
  // tracking area.  Note that -clearOwner is NOT called on the existing
  // tracking area.
  void reset(CrTrackingArea* tracking_area = nil);

  CrTrackingArea* get() const;

 private:
  scoped_nsobject<CrTrackingArea> tracking_area_;
  DISALLOW_COPY_AND_ASSIGN(ScopedCrTrackingArea);
};

#endif  // CHROME_BROWSER_UI_COCOA_TRACKING_AREA_H_