pjs/xpcom/public/nsIServiceManager.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* 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 nsIServiceManager_h___
#define nsIServiceManager_h___
#include "nsRepository.h"
class nsIShutdownListener;
/**
* The nsIServiceManager manager interface provides a means to obtain
* global services in an application. The service manager depends on the
* repository to find and instantiate factories to obtain services.
*
* Users of the service manager must first obtain a pointer to the global
* service manager by calling NS_GetGlobalServiceManager. After that,
* they can request specific services by calling GetService. When they are
* finished with a service the release it by calling ReleaseService (instead
* of releasing the service object directly):
*
* nsICacheManager* cm;
* nsServiceManager::GetService(kCacheManagerCID, kICacheManagerIID, (nsISupports**)&cm);
*
* ... use cm, and then sometime later ...
*
* nsServiceManager::ReleaseService(kCacheManagerCID, cm);
*
* A user of a service may keep references to particular services indefinitely
* and only must call ReleaseService when it shuts down. However if the user
* wishes to voluntarily cooperate with the shutdown of the service it is
* using, it may supply an nsIShutdownListener to provide for asynchronous
* release of the services it is using. The shutdown listener's OnShutdown
* method will be called for a service that is being shut down, and it is
* its responsiblity to release references obtained from that service if at
* all possible.
*
* The process of shutting down a particular service is initiated by calling
* the service manager's ShutdownService method. This will iterate through
* all the registered shutdown listeners for the service being shut down, and
* then will attempt to unload the library associated with the service if
* possible. The status result of ShutdownService indicates whether the
* service was successfully shut down, failed, or was not in service.
*
* XXX QUESTIONS:
* - Should a "service" be more than nsISupports? Should it be a factory
* and/or have Startup(), Shutdown(), etc.
* - If the asynchronous OnShutdown operation gets called, does the user
* of a service still need to call ReleaseService? (Or should they _not_
* call it?)
*/
class nsIServiceManager : public nsISupports {
public:
NS_IMETHOD
GetService(const nsCID& aClass, const nsIID& aIID,
nsISupports* *result,
nsIShutdownListener* shutdownListener = NULL) = 0;
NS_IMETHOD
ReleaseService(const nsCID& aClass, nsISupports* service,
nsIShutdownListener* shutdownListener = NULL) = 0;
/**
* Requests a service to be shut down, possibly unloading its DLL.
*
* @returns NS_OK - if shutdown was successful and service was unloaded,
* @returns NS_ERROR_SERVICE_NOT_FOUND - if shutdown failed because
* the service was not currently loaded
* @returns NS_ERROR_SERVICE_IN_USE - if shutdown failed because some
* user of the service wouldn't voluntarily release it by using
* a shutdown listener.
*/
NS_IMETHOD
ShutdownService(const nsCID& aClass) = 0;
};
#define NS_ISERVICEMANAGER_IID \
{ /* cf0df3b0-3401-11d2-8163-006008119d7a */ \
0xcf0df3b0, \
0x3401, \
0x11d2, \
{0x81, 0x63, 0x00, 0x60, 0x08, 0x11, 0x9d, 0x7a} \
}
#define NS_ERROR_SERVICE_NOT_FOUND NS_ERROR_GENERATE_SUCCESS(NS_ERROR_MODULE_XPCOM, 22)
#define NS_ERROR_SERVICE_IN_USE NS_ERROR_GENERATE_SUCCESS(NS_ERROR_MODULE_XPCOM, 23)
////////////////////////////////////////////////////////////////////////////////
class nsIShutdownListener : public nsISupports {
public:
NS_IMETHOD
OnShutdown(const nsCID& aClass, nsISupports* service) = 0;
};
#define NS_ISHUTDOWNLISTENER_IID \
{ /* 56decae0-3406-11d2-8163-006008119d7a */ \
0x56decae0, \
0x3406, \
0x11d2, \
{0x81, 0x63, 0x00, 0x60, 0x08, 0x11, 0x9d, 0x7a} \
}
////////////////////////////////////////////////////////////////////////////////
// Interface to Global Services
class NS_COM nsServiceManager {
public:
static nsresult GetService(const nsCID& aClass, const nsIID& aIID,
nsISupports* *result,
nsIShutdownListener* shutdownListener = NULL);
static nsresult ReleaseService(const nsCID& aClass, nsISupports* service,
nsIShutdownListener* shutdownListener = NULL);
static nsresult ShutdownService(const nsCID& aClass);
protected:
static nsresult GetGlobalServiceManager(nsIServiceManager* *result);
static nsIServiceManager* globalServiceManager;
};
////////////////////////////////////////////////////////////////////////////////
#endif /* nsIServiceManager_h___ */