1// Copyright (c) 2012 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 BASE_MAC_SCOPED_SENDING_EVENT_H_
6#define BASE_MAC_SCOPED_SENDING_EVENT_H_
7
8#include "base/base_export.h"
9#include "base/basictypes.h"
10#include "base/message_loop/message_pump_mac.h"
11
12// Nested event loops can pump IPC messages, including
13// script-initiated tab closes, which could release objects that the
14// nested event loop might message.  CrAppProtocol defines how to ask
15// the embedding NSApplication subclass if an event is currently being
16// handled, in which case such closes are deferred to the top-level
17// event loop.
18//
19// ScopedSendingEvent allows script-initiated event loops to work like
20// a nested event loop, as such events do not arrive via -sendEvent:.
21// CrAppControlProtocol lets ScopedSendingEvent tell the embedding
22// NSApplication what to return from -handlingSendEvent.
23
24@protocol CrAppControlProtocol<CrAppProtocol>
25- (void)setHandlingSendEvent:(BOOL)handlingSendEvent;
26@end
27
28namespace base {
29namespace mac {
30
31class BASE_EXPORT ScopedSendingEvent {
32 public:
33  ScopedSendingEvent();
34  ~ScopedSendingEvent();
35
36 private:
37  // The NSApp in control at the time the constructor was run, to be
38  // sure the |handling_| setting is restored appropriately.
39  NSObject<CrAppControlProtocol>* app_;
40  BOOL handling_;  // Value of -[app_ handlingSendEvent] at construction.
41
42  DISALLOW_COPY_AND_ASSIGN(ScopedSendingEvent);
43};
44
45}  // namespace mac
46}  // namespace base
47
48#endif  // BASE_MAC_SCOPED_SENDING_EVENT_H_
49