com 技术内幕的例子

 最近开始学习com知识，看的是com技术内幕的，跟着书中的例子,手工完成com的创建，没想到因为一个AddRef和Release的问题，让我调试了好几天，才最终实现，现在把代码，贴出来，以防忘记。

GUID定义文件。

#ifndef __GUID_H__ #define __GUID_H__ #include <Guiddef.h> static const IID IID_IX = { 0x4c4f852c, 0xf4c7, 0x4ee9, { 0xb8, 0xc1, 0x75, 0x75, 0x88, 0x6c, 0xf6, 0x4b } }; // {ED29E415-1A9F-4d23-B859-B48DA72CC809} static const IID IID_IY = { 0xed29e415, 0x1a9f, 0x4d23, { 0xb8, 0x59, 0xb4, 0x8d, 0xa7, 0x2c, 0xc8, 0x9 } }; // {FE780C2C-7A30-4d00-AD92-F2DA3294ECDE} static const IID IID_IZ = { 0xfe780c2c, 0x7a30, 0x4d00, { 0xad, 0x92, 0xf2, 0xda, 0x32, 0x94, 0xec, 0xde } }; // {6CD33DA1-61DD-415f-951C-2C8963736B40} static const IID IID_IW = { 0x6cd33da1, 0x61dd, 0x415f, { 0x95, 0x1c, 0x2c, 0x89, 0x63, 0x73, 0x6b, 0x40 } }; // {D346F3F5-F7BB-494a-B9DB-ED19642D827E} static const CLSID CLSID_Com_Test = { 0xd346f3f5, 0xf7bb, 0x494a, { 0xb9, 0xdb, 0xed, 0x19, 0x64, 0x2d, 0x82, 0x7e } }; #endif //__GUID_H__

 接口定义定义头文件:

#ifndef __IX__H__ #define __IX__H__ #include <iostream> #include <ObjBase.h> #include "guid.h" using namespace std; //void trace(const char* msg) //{ // cout << msg << endl; //} interface IX : IUnknown { virtual void __stdcall Fx() = 0; }; interface IY : IUnknown { virtual void __stdcall Fy() = 0; }; interface IZ: IUnknown { virtual void __stdcall Fz() = 0; }; class CA : public IX,IY,IZ { public: CA():m_count_(0){} ~CA(); virtual HRESULT __stdcall QueryInterface(const IID& iid, void** ppv); virtual ULONG __stdcall AddRef() { InterlockedIncrement(&m_count_); cout << "add ref" << endl; return m_count_; } virtual ULONG __stdcall Release() { InterlockedDecrement(&m_count_); if (m_count_ == 0) { cout << "delete " << endl; delete this; return 0; } cout << "release " << endl; return m_count_; } virtual void __stdcall Fx() { cout << "fx()" << endl; } virtual void __stdcall Fy() { cout << "fy()" << endl; } virtual void __stdcall Fz() { cout << "fz()" << endl; } private: long m_count_; }; extern "C" __declspec(dllexport) IUnknown* CreateInstance(); #endif

类工厂的头文件：

#pragma once #include <ObjBase.h> class CMyClassFactory : public IClassFactory { public: CMyClassFactory(void); ~CMyClassFactory(void); public: virtual HRESULT __stdcall QueryInterface(REFIID riid, __RPC__deref_out void **ppvObject); virtual ULONG __stdcall AddRef(); virtual ULONG __stdcall Release(); virtual HRESULT __stdcall CreateInstance( IUnknown *pUnkOuter,REFIID riid,void **ppvObject); virtual HRESULT __stdcall LockServer(BOOL fLock); private: long m_count_; };

接口的实现：

 #include "StdAfx.h" #include "IX.h" HRESULT CA::QueryInterface(const IID& iid, void** ppv) { cout << "query interface " << endl; if (iid == IID_IUnknown ) { cout << "IUnknown interface ptr "; *ppv = static_cast<IX*>(this); } else if (iid == IID_IX ) { cout << "IX interface ptr "; *ppv = static_cast<IX*> (this); } else if (iid == IID_IY) { cout << "IY interface ptr "; *ppv = static_cast<IY*>(this); } else if (iid == IID_IZ) { cout << "IZ interface ptr "; *ppv = static_cast<IZ*>(this); } else { cout << "not find interface "; *ppv = NULL; return E_NOINTERFACE; } reinterpret_cast<IUnknown*>(*ppv)->AddRef(); return S_OK; } IUnknown* CreateInstance() { IUnknown* ptr = static_cast<IX*>(new CA()); ptr ->AddRef(); return ptr; } CA::~CA() { cout << "delete ca " << endl; }

类厂的实现:

#include "StdAfx.h" #include "MyClassFactory.h" #include "IX.h" #include <iostream> using namespace std; long g_server_lock; CMyClassFactory::CMyClassFactory(void) { cout << "类厂的构造函数" << endl; m_count_ = 0; } CMyClassFactory::~CMyClassFactory(void) { cout << "类厂的析构函数" << endl; } HRESULT __stdcall CMyClassFactory::QueryInterface( REFIID riid, __RPC__deref_out void **ppvObject ) { if (IID_IUnknown == riid) { *ppvObject = static_cast<IUnknown*>(this); } else if(IID_IClassFactory == riid) { *ppvObject = static_cast<IClassFactory*>(this); } else { *ppvObject = NULL; return E_NOINTERFACE; } reinterpret_cast<IUnknown*>(*ppvObject)->AddRef(); return S_OK; } ULONG __stdcall CMyClassFactory::AddRef() { InterlockedIncrement(&m_count_); return m_count_; } ULONG __stdcall CMyClassFactory::Release() { InterlockedDecrement(&m_count_); if (m_count_ == 0) { delete this; return 0; } return m_count_; } HRESULT __stdcall CMyClassFactory::LockServer( BOOL fLock ) { if (fLock) { InterlockedIncrement(&g_server_lock); }else { InterlockedDecrement(&g_server_lock); } return S_OK; } HRESULT __stdcall CMyClassFactory::CreateInstance( IUnknown *pUnkOuter,REFIID riid,void **ppvObject ) { if (pUnkOuter != NULL ) { return CLASS_E_NOAGGREGATION; } CA* pca = new CA(); if (pca == NULL) { return E_OUTOFMEMORY; } HRESULT hr = pca->QueryInterface(riid,ppvObject); return hr; }

dll文件 导出实现:

// com_test.cpp : 定义控制台应用程序的入口点。 // #include "stdafx.h" #include <iostream> #include "guid.h" #include <Windows.h> #include "MyClassFactory.h" HMODULE g_module; using namespace std; #define DLLEXPORTSTDAPI STDAPI const char * g_RegTable[][3]={ {"CLSID//{D346F3F5-F7BB-494a-B9DB-ED19642D827E1}",0,"jamy.com"}, {"CLSID//{D346F3F5-F7BB-494a-B9DB-ED19642D827E}//InprocServer32", 0, (const char * )-1 /*表示文件名的值*/}, {"CLSID//{D346F3F5-F7BB-494a-B9DB-ED19642D827E}//ProgID",0,"jamy.com"}, {"jam.COM.1",0,"JamyCOM"}, {"jamy.COM.1//CLSID",0,"{D346F3F5-F7BB-494a-B9DB-ED19642D827E}"}, }; HINSTANCE g_hinstDll; BOOL __stdcall DllMain(_In_ HANDLE _HDllHandle, _In_ DWORD _Reason, _In_opt_ LPVOID _Reserved) { if (_Reason == DLL_PROCESS_ATTACH) { g_module =(HMODULE) _HDllHandle; cout << "dll main " << endl; g_hinstDll = (HMODULE)_HDllHandle; } if (_Reason == DLL_PROCESS_DETACH) { cout << "exit dll " << endl; } return true; } STDAPI DllGetClassObject( REFCLSID rclsid, REFIID riid, void** ppv) { if (rclsid != CLSID_Com_Test ) { return CLASS_E_CLASSNOTAVAILABLE; } CMyClassFactory* pmcf = new CMyClassFactory(); if (pmcf == NULL) { return E_OUTOFMEMORY; } HRESULT hr = pmcf->QueryInterface(riid,ppv); return hr; } DLLEXPORTSTDAPI DllUnregisterServer() { HRESULT hr=S_OK; char szFileName [MAX_PATH]; ::GetModuleFileNameA(g_hinstDll,szFileName,MAX_PATH); int nEntries=sizeof(g_RegTable)/sizeof(*g_RegTable); for(int i =0;SUCCEEDED(hr)&&i<nEntries;i++) { const char * pszKeyName=g_RegTable[i][0]; long err=::RegDeleteKeyA(HKEY_CLASSES_ROOT,pszKeyName); if(err!=ERROR_SUCCESS) hr=S_FALSE; } return hr; return hr; } DLLEXPORTSTDAPI DllRegisterServer() { HRESULT hr=S_OK; char szFileName [MAX_PATH]; ::GetModuleFileNameA(g_hinstDll,szFileName,MAX_PATH); int nEntries=sizeof(g_RegTable)/sizeof(*g_RegTable); for(int i =0;SUCCEEDED(hr)&&i<nEntries;i++) { const char * pszKeyName=g_RegTable[i][0]; const char * pszValueName=g_RegTable[i][1]; const char * pszValue=g_RegTable[i][2]; if(pszValue==(const char *)-1) { pszValue=szFileName; } HKEY hkey; long err=::RegCreateKeyA(HKEY_CLASSES_ROOT,pszKeyName,&hkey); if(err==ERROR_SUCCESS) { err=::RegSetValueExA( hkey, pszValueName, 0, REG_SZ, ( const BYTE*)pszValue, ( strlen(pszValue)+1 ) ); ::RegCloseKey(hkey); } if(err!=ERROR_SUCCESS) { ::DllUnregisterServer(); hr=E_FAIL; } } return hr; } STDAPI DllCanUnloadNow() { return E_FAIL; }

dll导出的def文件：

LIBRARY "com_test" EXPORTS DllGetClassObject @1 private DllUnregisterServer @2 private DllRegisterServer @3 private DllCanUnloadNow @4 private

客户端调用:

// test_dll.cpp : 定义控制台应用程序的入口点。 // #include "stdafx.h" #include "d://MyProject//vs2008//C++//cpp_review//com_test//com_test//IX.h" #include "d://MyProject//vs2008//C++//cpp_review//com_test//com_test//guid.h" #include "d://MyProject//vs2008//C++//cpp_review//com_test//com_test//MyClassFactory.h" #include <ObjBase.h> #include <iostream> using namespace std; typedef IUnknown* (*CREATEINSTANCEPTR)(); IUnknown* CallCreateInstance(wchar_t* DllPath) { HINSTANCE hComp = ::LoadLibrary(DllPath); if (hComp == NULL) { wcout << DllPath << "不存在" << endl; return NULL; } CREATEINSTANCEPTR pCreateInstance = (CREATEINSTANCEPTR)::GetProcAddress(hComp,"CreateInstance"); if (pCreateInstance == NULL) { cout << "无法找到函数 CreateInstance" << endl; return NULL; } return pCreateInstance(); } int _tmain(int argc, _TCHAR* argv[]) { /*IUnknown* ptr = CallCreateInstance(_T("D://MyProject//vs2008//C++//cpp_review//test_dll//Debug//com_test.dll")); if (ptr == NULL) { cout << "call createinstance error " << endl; return 0; } */ CoInitialize(NULL); IX* pIX = NULL; IClassFactory* pIcf = NULL; //如果有异常发生，可能是引用计数有问题，就是在这纠结我好几天 HRESULT hr = ::CoCreateInstance(CLSID_Com_Test,NULL,CLSCTX_INPROC_SERVER,IID_IX,(void**)&pIX); // HRESULT hr = ::CoGetClassObject(CLSID_Com_Test,CLSCTX_INPROC_SERVER,NULL,IID_IClassFactory,(void**)&pIcf); //if (SUCCEEDED(hr)) //{ // hr = pIcf->CreateInstance(NULL,IID_IX,(void**)&pIX); // pIcf->Release(); //} //else //{ // exit(-1); //} if (FAILED(hr)) { DWORD err =GetLastError(); cout << "错误代码:" << err << endl; CoUninitialize(); exit(-2); } pIX->Fx(); IY* pIY = NULL; hr = pIX->QueryInterface(IID_IY,(void**)&pIY); if (SUCCEEDED(hr)) { pIY->Fy(); } IZ* pIZ = NULL; hr = pIY->QueryInterface(IID_IZ,(void**)&pIZ); if (SUCCEEDED(hr)) { pIZ->Fz(); } pIZ->Release(); pIY->Release(); pIX->Release(); CoUninitialize(); return 0; }