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 CHROME_BROWSER_UI_COCOA_COMMAND_OBSERVER_BRIDGE
6#define CHROME_BROWSER_UI_COCOA_COMMAND_OBSERVER_BRIDGE
7
8#import <Cocoa/Cocoa.h>
9
10#include "base/compiler_specific.h"
11#include "chrome/browser/command_observer.h"
12
13@protocol CommandObserverProtocol;
14
15class CommandUpdater;
16
17// A C++ bridge class that handles listening for updates to commands and
18// passing them back to an object that supports the protocol delcared below.
19// The observer will create one of these bridges, call ObserveCommand() on the
20// command ids it cares about, and then wait for update notifications,
21// delivered via -enabledStateChangedForCommand:enabled:. Destroying this
22// bridge will handle automatically unregistering for updates, so there's no
23// need to do that manually.
24
25class CommandObserverBridge : public CommandObserver {
26 public:
27  CommandObserverBridge(id<CommandObserverProtocol> observer,
28                        CommandUpdater* commands);
29  virtual ~CommandObserverBridge();
30
31  // Register for updates about |command|.
32  void ObserveCommand(int command);
33
34 protected:
35  // Overridden from CommandObserver
36  virtual void EnabledStateChangedForCommand(int command,
37                                             bool enabled) OVERRIDE;
38
39 private:
40  id<CommandObserverProtocol> observer_;  // weak, owns me
41  CommandUpdater* commands_;  // weak
42};
43
44// Implemented by the observing Objective-C object, called when there is a
45// state change for the given command.
46@protocol CommandObserverProtocol
47- (void)enabledStateChangedForCommand:(NSInteger)command enabled:(BOOL)enabled;
48@end
49
50#endif  // CHROME_BROWSER_UI_COCOA_COMMAND_OBSERVER_BRIDGE
51