gecko-dev/xpcom/components/nsXPComFactory.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* The contents of this file are subject to the Netscape Public License
* Version 1.0 (the "License"); you may not use this file except in
* compliance with the License. You may obtain a copy of the License at
* http://www.mozilla.org/NPL/
*
* Software distributed under the License is distributed on an "AS IS"
* basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
* the License for the specific language governing rights and limitations
* under the License.
*
* The Original Code is Mozilla Communicator client code.
*
* The Initial Developer of the Original Code is Netscape Communications
* Corporation. Portions created by Netscape are Copyright (C) 1998
* Netscape Communications Corporation. All Rights Reserved.
*/
#ifndef nsXPComFactory_h__
#define nsXPComFactory_h__
#include "nsIFactory.h"
/*
* This file contains a macro for the implementation of a simple XPCOM factory.
*
* To implement a factory for a given component, you need to declare the
* factory class using the NS_DEF_FACTORY() macro.
*
* The first macro argument is the name for the factory.
*
* The second macro argument is a function (provided by you) which
* can be called by your DLL's NSGetFactory(...) entry point.
*
* Example:
*
* NS_DEF_FACTORY(SomeComponent,SomeComponentImpl)
*
* Declares:
*
* class nsSomeComponentFactory : public nsIFactory {};
*
* NOTE that the NS_DEF_FACTORY takes care of enforcing the "ns" prefix
* and appending the "Factory" suffix to the given name.
*
* To use the new factory:
*
* nsresult NS_New_SomeComponent_Factory(nsIFactory** aResult)
* {
* nsresult rv = NS_OK;
* nsIFactory* inst = new nsSomeComponentFactory;
* if (NULL == inst) {
* rv = NS_ERROR_OUT_OF_MEMORY;
* } else {
* NS_ADDREF(inst);
* }
* *aResult = inst;
* return rv;
* }
*
* NOTE:
* ----
* The factories created by this macro are not thread-safe and do not
* support aggregation.
*
*/
#define NS_DEF_FACTORY(_name,_type) \
class ns##_name##Factory : public nsIFactory \
{ \
public: \
ns##_name##Factory() { NS_INIT_REFCNT(); } \
\
NS_IMETHOD_(nsrefcnt) AddRef (void) \
{ \
return ++mRefCnt; \
} \
\
NS_IMETHOD_(nsrefcnt) Release(void) \
{ \
NS_PRECONDITION(0 != mRefCnt, "dup release"); \
if (--mRefCnt == 0) { \
NS_DELETEXPCOM(this); \
return 0; \
} \
return mRefCnt; \
} \
\
NS_IMETHOD QueryInterface(REFNSIID aIID, void** aInstancePtr) \
{ \
if (NULL == aInstancePtr) { \
return NS_ERROR_NULL_POINTER; \
} \
\
*aInstancePtr = NULL; \
\
static NS_DEFINE_IID(kIFactoryIID, NS_IFACTORY_IID); \
static NS_DEFINE_IID(kISupportsIID, NS_ISUPPORTS_IID); \
if (aIID.Equals(kIFactoryIID)) { \
*aInstancePtr = (void*) this; \
NS_ADDREF_THIS(); \
return NS_OK; \
} \
if (aIID.Equals(kISupportsIID)) { \
*aInstancePtr = (void*) ((nsISupports*)this); \
NS_ADDREF_THIS(); \
return NS_OK; \
} \
return NS_NOINTERFACE; \
} \
\
NS_IMETHOD CreateInstance(nsISupports *aOuter, \
const nsIID &aIID, \
void **aResult) \
{ \
nsresult rv; \
\
_type * inst; \
\
if (NULL == aResult) { \
rv = NS_ERROR_NULL_POINTER; \
goto done; \
} \
*aResult = NULL; \
if (NULL != aOuter) { \
rv = NS_ERROR_NO_AGGREGATION; \
goto done; \
} \
\
NS_NEWXPCOM(inst, _type); \
if (NULL == inst) { \
rv = NS_ERROR_OUT_OF_MEMORY; \
goto done; \
} \
NS_ADDREF(inst); \
rv = inst->QueryInterface(aIID, aResult); \
NS_RELEASE(inst); \
\
done: \
return rv; \
} \
\
NS_IMETHOD LockFactory(PRBool aLock) \
{ \
return NS_OK; \
} \
\
\
protected: \
virtual ~ns##_name##Factory() \
{ \
NS_ASSERTION(mRefCnt == 0, "non-zero refcnt at destruction"); \
} \
\
nsrefcnt mRefCnt; \
};
#endif /* nsXPComFactory_h__ */