chrome/browser/ui/cocoa/command_observer_bridge.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 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
  15 class 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
  25 class 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