/* -*- Mode: C++; tab-width: 4; 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. */ #include "nsISupports.h" //////////////////////////////////////////////////////////////////////////////// // nsIFoo.h //////////////////////////////////////////////////////////////////////////////// // Here's an interface that we're going to work with. Normally it would be // defined in nsIFoo.h: #define NS_IFOO_IID \ { /* f981ba10-1547-11d3-9337-00104ba0fd40 */ \ 0xf981ba10, \ 0x1547, \ 0x11d3, \ {0x93, 0x37, 0x00, 0x10, 0x4b, 0xa0, 0xfd, 0x40} \ } #define NS_FOO_CID \ { /* fe1a5870-1547-11d3-9337-00104ba0fd40 */ \ 0xfe1a5870, \ 0x1547, \ 0x11d3, \ {0x93, 0x37, 0x00, 0x10, 0x4b, 0xa0, 0xfd, 0x40} \ } class nsIFoo : public nsISupports { public: NS_DEFINE_STATIC_IID_ACCESSOR(NS_IFOO_IID); NS_IMETHOD Init(const char* name) = 0; NS_IMETHOD Doit(int x) = 0; }; // Define a global constructor function if you really need one. Otherwise // you can always use nsIComponentManager::CreateInstance. PR_EXTERN(nsresult) NS_NewFoo(nsIFoo* *result, const char* name); //////////////////////////////////////////////////////////////////////////////// // nsFoo.h //////////////////////////////////////////////////////////////////////////////// // Here's the implementation class definition. Put this in an nsFoo.h (and don't // export it to dist). //#include "nsIFoo.h" class nsFoo : public nsIFoo { public: // Define the constructor, but don't give it arguments that are needed // for initialization that can fail: nsFoo(); // Always make the destructor virtual: virtual ~nsFoo(); // Define a Create method to be used with a factory: static NS_METHOD Create(nsISupports* aOuter, const nsIID& aIID, void* *aResult); // from nsIFoo: NS_IMETHOD Init(const char* name); NS_IMETHOD Doit(int x); // from nsISupports: NS_DECL_ISUPPORTS protected: // instance variables: char* mName; }; //////////////////////////////////////////////////////////////////////////////// // nsFoo.cpp //////////////////////////////////////////////////////////////////////////////// // Here's the implementation. Put this in an nsFoo.cpp. //#include "nsFoo.h" #include "nsCRT.h" #include // Don't do anything in the constructor that can fail. Just initialize all // the instance variables and get out: nsFoo::nsFoo() : mName(NULL) { NS_INIT_REFCNT(); } // Do anything that can fail in the Init method. It's a good idea to provide // one so that in the future if someone adds something that can fail they'll // be encouraged to do it right: NS_IMETHODIMP nsFoo::Init(const char* name) { mName = nsCRT::strdup(name); if (mName == NULL) return NS_ERROR_OUT_OF_MEMORY; return NS_OK; } // Destroy and release things as usual in the destructor: nsFoo::~nsFoo() { if (mName) nsCRT::free(mName); } // Provide a Create method that can be called by a factory constructor: NS_METHOD nsFoo::Create(nsISupports* aOuter, const nsIID& aIID, void* *aResult) { if (aOuter) return NS_ERROR_NO_AGGREGATION; nsFoo* foo = new nsFoo(); if (foo == NULL) return NS_ERROR_OUT_OF_MEMORY; // Note that Create doesn't initialize the instance -- that has to // be done by the caller since the initialization args aren't passed // in here. // AddRef before calling QI -- this makes it easier to handle the QI // failure case because we'll always just Release and return NS_ADDREF(foo); nsresult rv = foo->QueryInterface(aIID, aResult); // This will free it if QI failed: NS_RELEASE(foo); return rv; } // Implement the nsISupports methods: NS_IMPL_ISUPPORTS(nsFoo, nsIFoo::GetIID()); // Implement the method(s) of the interface: NS_IMETHODIMP nsFoo::Doit(int x) { printf("%s %d\n", mName, x); return NS_OK; } // Finally, (if you really need one) implement a global constructor function // for this class: PR_IMPLEMENT(nsresult) NS_NewFoo(nsIFoo* *result, const char* name) { // Use the constructor method to create this. Don't duplicate work. nsresult rv = nsFoo::Create(NULL, nsIFoo::GetIID(), (void**)result); if (NS_SUCCEEDED(rv)) { // Only initialize if the constructor succeeded: rv = (*result)->Init(name); } return rv; } //////////////////////////////////////////////////////////////////////////////// // nsFooModuleFactory.cpp //////////////////////////////////////////////////////////////////////////////// // This file defines the factory that instantiates nsFoo and any other classes // in the same component. It also defines the component's NSGetFactory, // NSRegisterSelf and NSUnregisterSelf entry points: // Include nsFoo.h to get the nsFoo::Create method: //#include "nsFoo.h" #include "nsIComponentManager.h" #include "nsIServiceManager.h" // Include the generic factory stuff. It's the easiest and smallest way to // work with factories: #include "nsGenericFactory.h" static NS_DEFINE_CID(kFooCID, NS_FOO_CID); static NS_DEFINE_CID(kComponentManagerCID, NS_COMPONENTMANAGER_CID); extern "C" PR_IMPLEMENT(nsresult) NSGetFactory(nsISupports* aServMgr, const nsCID &aClass, const char *aClassName, const char *aProgID, nsIFactory **aFactory) { nsresult rv; nsIGenericFactory* fact; if (aClass.Equals(kFooCID)) rv = NS_NewGenericFactory(&fact, nsFoo::Create); else rv = NS_ERROR_FAILURE; if (NS_SUCCEEDED(rv)) *aFactory = fact; return rv; } extern "C" PR_IMPLEMENT(nsresult) NSRegisterSelf(nsISupports* aServMgr , const char* aPath) { nsresult rv; NS_WITH_SERVICE1(nsIComponentManager, compMgr, aServMgr, kComponentManagerCID, &rv); if (NS_FAILED(rv)) return rv; rv = compMgr->RegisterComponent(kFooCID, "Foo", NULL, aPath, PR_TRUE, PR_TRUE); return rv; } extern "C" PR_IMPLEMENT(nsresult) NSUnregisterSelf(nsISupports* aServMgr, const char* aPath) { nsresult rv; NS_WITH_SERVICE1(nsIComponentManager, compMgr, aServMgr, kComponentManagerCID, &rv); if (NS_FAILED(rv)) return rv; rv = compMgr->UnregisterComponent(kFooCID, aPath); return rv; } ////////////////////////////////////////////////////////////////////////////////