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154 lines
3.8 KiB
C++
154 lines
3.8 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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*
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* The contents of this file are subject to the Netscape Public License
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* Version 1.0 (the "License"); you may not use this file except in
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* compliance with the License. You may obtain a copy of the License at
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* http://www.mozilla.org/NPL/
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*
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* Software distributed under the License is distributed on an "AS IS"
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* basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
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* the License for the specific language governing rights and limitations
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* under the License.
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*
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* The Original Code is Mozilla Communicator client code.
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*
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* The Initial Developer of the Original Code is Netscape Communications
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* Corporation. Portions created by Netscape are Copyright (C) 1998
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* Netscape Communications Corporation. All Rights Reserved.
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*/
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#ifndef nsXPComFactory_h__
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#define nsXPComFactory_h__
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#include "nsIFactory.h"
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/*
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* This file contains a templatized implementation of a simple XPCOM factory.
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*
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* To implement a factory for a given component, just provide a function
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* like the one below which can be called by your DLL's NSGetFactory(...)
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* entry point...
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*
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* nsresult NS_New_SomeComponent_Factory(nsIFactory** aResult)
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* {
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* nsresult rv = NS_OK;
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* nsIFactory* inst = new nsFactory<SomeComponent>();
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* if (NULL == inst) {
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* rv = NS_ERROR_OUT_OF_MEMORY;
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* } else {
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* NS_ADDREF(inst);
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* }
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* *aResult = inst;
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* return rv;
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* }
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*
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* NOTE:
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* ----
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* The factories created by this template are not thread-safe and do not
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* support aggregation.
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*
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*/
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template <class T> class nsFactory : public nsIFactory
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{
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public:
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nsFactory() { NS_INIT_REFCNT(); }
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//
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// nsISupports interface...
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//
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// These implementations were copied from the NS_IMPL_ISUPPORTS macro
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// in nsISupports.h
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//
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NS_IMETHOD_(nsrefcnt) AddRef (void)
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{
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return ++mRefCnt;
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}
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NS_IMETHOD_(nsrefcnt) Release(void)
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{
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NS_PRECONDITION(0 != mRefCnt, "dup release");
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if (--mRefCnt == 0) {
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NS_DELETEXPCOM(this);
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return 0;
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}
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return mRefCnt;
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}
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NS_IMETHOD QueryInterface(REFNSIID aIID, void** aInstancePtr)
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{
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if (NULL == aInstancePtr) {
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return NS_ERROR_NULL_POINTER;
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}
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*aInstancePtr = NULL;
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static NS_DEFINE_IID(kIFactoryIID, NS_IFACTORY_IID);
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static NS_DEFINE_IID(kISupportsIID, NS_ISUPPORTS_IID);
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if (aIID.Equals(kIFactoryIID)) {
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*aInstancePtr = (void*) this;
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NS_ADDREF_THIS();
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return NS_OK;
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}
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if (aIID.Equals(kISupportsIID)) {
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*aInstancePtr = (void*) ((nsISupports*)this);
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NS_ADDREF_THIS();
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return NS_OK;
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}
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return NS_NOINTERFACE;
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}
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//
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// nsIFactory interface...
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//
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NS_IMETHOD CreateInstance(nsISupports *aOuter,
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const nsIID &aIID,
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void **aResult)
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{
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nsresult rv;
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T* inst;
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// Parameter validation...
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if (NULL == aResult) {
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rv = NS_ERROR_NULL_POINTER;
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goto done;
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}
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// Do not support aggregatable components...
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*aResult = NULL;
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if (NULL != aOuter) {
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rv = NS_ERROR_NO_AGGREGATION;
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goto done;
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}
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// Create a new instance of the component...
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NS_NEWXPCOM(inst, T);
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if (NULL == inst) {
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rv = NS_ERROR_OUT_OF_MEMORY;
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goto done;
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}
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// If the QI fails, the component will be destroyed...
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NS_ADDREF(inst);
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rv = inst->QueryInterface(aIID, aResult);
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NS_RELEASE(inst);
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done:
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return rv;
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}
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NS_IMETHOD LockFactory(PRBool aLock)
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{
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// Not implemented in simplest case.
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return NS_OK;
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}
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protected:
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virtual ~nsFactory()
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{
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NS_ASSERTION(mRefCnt == 0, "non-zero refcnt at destruction");
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}
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// Reference count variable used by nsISupports...
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nsrefcnt mRefCnt;
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};
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#endif /* nsXPComFactory_h__ */
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