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// Copyright 2015 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 UI_BASE_COCOA_COMMAND_DISPATCHER_H_
#define UI_BASE_COCOA_COMMAND_DISPATCHER_H_
#import <Cocoa/Cocoa.h>
#import "base/mac/scoped_nsobject.h"
#include "ui/base/ui_base_export.h"
@protocol CommandDispatcherDelegate;
@protocol CommandDispatchingWindow;
@protocol UserInterfaceItemCommandHandler;
// CommandDispatcher guides the processing of key events to ensure key commands
// are executed in the appropriate order. In particular, it allows a first
// responder implementing CommandDispatcherTarget to handle an event
// asynchronously and return unhandled events via -redispatchKeyEvent:. An
// NSWindow can use CommandDispatcher by implementing CommandDispatchingWindow
// and overriding -[NSWindow performKeyEquivalent:] and -[NSWindow sendEvent:]
// to call the respective CommandDispatcher methods.
UI_BASE_EXPORT @interface CommandDispatcher : NSObject
@property(assign, nonatomic) id<CommandDispatcherDelegate> delegate;
- (instancetype)initWithOwner:(NSWindow<CommandDispatchingWindow>*)owner;
// The main entry point for key events. The CommandDispatchingWindow should
// override -[NSResponder performKeyEquivalent:] and call this instead. Returns
// YES if the event is handled.
- (BOOL)performKeyEquivalent:(NSEvent*)event;
// Sends a key event to -[NSApp sendEvent:]. This is used to allow default
// AppKit handling of an event that comes back from CommandDispatcherTarget,
// e.g. key equivalents in the menu, or window manager commands like Cmd+`. Once
// the event returns to the window at -preSendEvent:, handling will stop. The
// event must be of type |NSKeyDown|, |NSKeyUp|, or |NSFlagsChanged|. Returns
// YES if the event is handled.
- (BOOL)redispatchKeyEvent:(NSEvent*)event;
// The CommandDispatchingWindow should override -[NSWindow sendEvent:] and call
// this before a native -sendEvent:. Ensures that a redispatched event is not
// reposted infinitely. Returns YES if the event is handled.
- (BOOL)preSendEvent:(NSEvent*)event;
@end
// If the NSWindow's firstResponder implements CommandDispatcherTarget, it is
// given the first opportunity to process a command.
@protocol CommandDispatcherTarget
// To handle an event asynchronously, return YES. If the event is ultimately not
// handled, return the event to the CommandDispatchingWindow via -[[event
// window] redispatchKeyEvent:event].
- (BOOL)performKeyEquivalent:(NSEvent*)event;
@end
// Provides CommandDispatcher with the means to redirect key equivalents at
// different stages of event handling.
@protocol CommandDispatcherDelegate<NSObject>
// Called before any other event handling, and possibly again if an unhandled
// event comes back from CommandDispatcherTarget.
- (BOOL)eventHandledByExtensionCommand:(NSEvent*)event
isRedispatch:(BOOL)isRedispatch;
// Called before the default -performKeyEquivalent:, but after the
// CommandDispatcherTarget has had a chance to intercept it. |window| is the
// CommandDispatchingWindow that owns CommandDispatcher.
- (BOOL)prePerformKeyEquivalent:(NSEvent*)event window:(NSWindow*)window;
// Called after the default -performKeyEquivalent:. |window| is the
// CommandDispatchingWindow that owns CommandDispatcher.
- (BOOL)postPerformKeyEquivalent:(NSEvent*)event window:(NSWindow*)window;
@end
// The set of methods an NSWindow subclass needs to implement to use
// CommandDispatcher.
@protocol CommandDispatchingWindow
// If set, NSUserInterfaceItemValidations for -commandDispatch: and
// -commandDispatchUsingKeyModifiers: will be redirected to the command handler.
// Retains |commandHandler|.
-(void)setCommandHandler:(id<UserInterfaceItemCommandHandler>) commandHandler;
// This can be implemented with -[CommandDispatcher redispatchKeyEvent:]. It's
// so that callers can simply return events to the NSWindow.
- (BOOL)redispatchKeyEvent:(NSEvent*)event;
// Short-circuit to the default -[NSResponder performKeyEquivalent:] which
// CommandDispatcher calls as part of its -performKeyEquivalent: flow.
- (BOOL)defaultPerformKeyEquivalent:(NSEvent*)event;
// AppKit will call -[NSUserInterfaceValidations validateUserInterfaceItem:] to
// validate UI items. Any item whose target is FirstResponder, or nil, will
// traverse the responder chain looking for a responder that implements the
// item's selector. Thus NSWindow is usually the last to be checked and will
// handle any items that are not validated elsewhere in the chain. Implement the
// following so that menu items with these selectors are validated by
// CommandDispatchingWindow.
- (void)commandDispatch:(id)sender;
- (void)commandDispatchUsingKeyModifiers:(id)sender;
@end
#endif // UI_BASE_COCOA_COMMAND_DISPATCHER_H_