gecko-dev/modules/libutil/public/xp_obs.h
1998-03-28 02:44:41 +00:00

159 lines
4.1 KiB
C

/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* The contents of this file are subject to the Netscape Public License
* Version 1.0 (the "NPL"); you may not use this file except in
* compliance with the NPL. You may obtain a copy of the NPL at
* http://www.mozilla.org/NPL/
*
* Software distributed under the NPL is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
* for the specific language governing rights and limitations under the
* NPL.
*
* The Initial Developer of this code under the NPL is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998 Netscape Communications Corporation. All Rights
* Reserved.
*/
#ifndef _xp_observer_h_
#define _xp_observer_h_
#if 0
#include "platform.h"
#else
#ifndef _platform_h_
typedef int NS_Error;
#endif
#endif
#include "prtypes.h"
typedef struct OpaqueObserverList *XP_ObserverList;
typedef void* XP_Observable;
typedef long XP_ObservableMsg;
typedef void (*XP_ObserverProc) (
XP_Observable inSource,
XP_ObservableMsg inMsg,
void* ioMsgData,
void* ioClosure );
XP_BEGIN_PROTOS
/*
Creates a new XP_ObserverList, with an assoicated XP_Observabe,
to which you can add observers, who are notified when
XP_NotifyObservers is called.
Observerer notification is enabled by default.
*/
extern NS_Error
XP_NewObserverList(
XP_Observable inObservable,
XP_ObserverList* outObserverList );
/*
Disposes of an XP_ObserverList. Does nothing with
its observers.
*/
extern void
XP_DisposeObserverList(
XP_ObserverList inObserverList );
/*
Returns the XP_Observable associated with an XP_ObserverList
*/
extern XP_Observable
XP_GetObserverListObservable(
XP_ObserverList inObserverList);
/*
Change the observable associated with an observerlist
*/
extern void
XP_SetObserverListObservable(
XP_ObserverList inObserverList,
XP_Observable inObservable);
/*
Registers a function pointer and void* closure
as an "observer", which will be called whenever
XP_NotifyObservers is called an observer notification
is enabled.
*/
extern int
XP_AddObserver(
XP_ObserverList inObserverList,
XP_ObserverProc inObserver,
void* inClosure );
/*
Removes a registered observer. If there are duplicate
(XP_ObserverProc/void* closure) pairs registered,
it is undefined which one will be removed.
Returns false if the observer is not registered.
*/
extern PRBool
XP_RemoveObserver(
XP_ObserverList inObserverList,
XP_ObserverProc inObserver,
void* inClosure );
/*
If observer notification is enabled for this XP_Observable,
this will call each registered observer proc, passing it
the given message and void* ioData, in addition to the
observer's closure void*.
There is no defined order in which observers are called.
*/
extern void
XP_NotifyObservers(
XP_ObserverList inObserverList,
XP_ObservableMsg inMessage,
void* ioData );
/*
When called, subsequent calls to XP_NotifyObservers
will do nothing until XP_EnableObserverNotification
is called.
*/
extern void
XP_DisableObserverNotification(
XP_ObserverList inObserverList );
/*
Enables calling observers when XP_NotifyObservers
is invoked.
*/
extern void
XP_EnableObserverNotification(
XP_ObserverList inObserverList );
/*
Returns true if observer notification is enabled.
*/
extern PRBool
XP_IsObserverNotificationEnabled(
XP_ObserverList inObserverList );
XP_END_PROTOS
#endif /* #ifdef _xp_observer_h_ */