Дональд Бокс - Сущность технологии СОМ. Библиотека программиста

• Название: Сущность технологии СОМ. Библиотека программиста
• Автор: Дональд Бокс
• Издательство: Питер
• Жанр: Программирование
• Год: 2001
• ISBN: 5-318-00058-4

В этой книге СОМ исследуется с точки зрения разработчика C++. Написанная ведущим специалистом по модели компонентных объектов СОМ, она раскрывает сущность СОМ, помогая разработчикам правильно понять не только методы модели программирования СОМ, но и ее основу. Понимание мотивов создания СОМ и ее аспектов, касающихся распределенных систем, чрезвычайно важно для тех разработчиков, которые желают пойти дальше простейших приложений СОМ и стать по-настоящему эффективными СОМ-программистами. Показывая, почему СОМ для распределенных систем (Distributed СОМ) работает именно так, а не иначе, Дон Бокс дает вам возможность применять эту модель творчески и эффективно для ежедневных задач программирования.

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static OLECHAR wszUserName[1024];

static OLECHAR wszPassword[1024];

static OLECHAR wszHostName[1024];

COSERVERINFO csi = { 0, wszHostName, 0, 0 };

COSERVERINFO *pcsi = 0;

COAUTHIDENTITY cai = {

wszUserName,

0,

wszDomainName,

0,

wszPassword,

0,

SEC_WINNT_AUTH_IDENTITY_UNICODE

};

static COAUTHIDENTITY *pcai = 0;

static ACTION action = ACTION_NONE;

// parse command line

for (int i = 1; i < argc; i++)

{

if (strcmp(argv[i], «/anonymous») == 0)

bAnonymous = true;

else if (strstr(argv[i], «/delete:») == argv[i])

{

if (action != ACTION_NONE)

return Usage();

action = ACTION_DELETE_SESSION;

mbstowcs(wszSessionName, argv[i] + 8, 1024);

}

else if (strstr(argv[i], «/chat:») == argv[i])

{

if (action != ACTION_NONE)

return Usage();

action = ACTION_CHAT;

mbstowcs(wszSessionName, argv[i] + 6, 1024);

}

else if (strcmp(argv[i], «/sessions») == 0)

{

if (action != ACTION_NONE)

return Usage();

action = ACTION_LIST_SESSION_NAMES;

}

else if (strstr(argv[i], «/host:») == argv[i])

{

if (pcsi != 0)

return Usage();

mbstowcs(wszHostName, argv[i] + 6, 1024);

pcsi = &csi;

}

else if (strstr(argv[i], «/password:») == argv[i])

{

mbstowcs(wszPassword, argv[i] + 10, 1024);

cai.PasswordLength = wcslen(wszPassword);

}

else if (strstr(argv[i], «/user:») == argv[i])

{

if (pcai != 0 || bAnonymous)

return Usage();

char *pszDelim = strchr(argv[i] + 7, '\\');

if (pszDelim == 0)

return Usage();

*pszDelim = 0;

pszDelim++;

mbstowcs(wszDomainName, argv[i] + 6, 1024);

cai.DomainLength = wcslen(wszDomainName);

mbstowcs(wszUserName, pszDelim, 1024);

cai.UserLength = wcslen(wszUserName);

pcai = &cai;

}

}

if (action == ACTION_NONE)

return Usage();

HRESULT hr = CoInitializeEx(0, COINIT_MULTITHREADED);

if (FAILED(hr))

return hr;

// allow anonymous callbacks from chat server

hr = CoInitializeSecurity(0, -1, 0, 0,

RPC_C_AUTHN_LEVEL_NONE,

RPC_C_IMP_LEVEL_ANONYMOUS,

0, EOAC_NONE, 0);

if (SUCCEEDED(hr))

{

// grab the requested session manager

IChatSessionManager *pcsm = 0;

hr = CoGetClassObject(CLSID_ChatSession, CLSCTX_ALL,

pcsi, IID_IChatSessionManager,

(void**)&pcsm);

if (SUCCEEDED(hr))

{

// apply security blanket if desired

if (!bAnonymous)

hr = CoSetProxyBlanket(pcsm, RPC_C_AUTHN_WINNT,

RPC_C_AUTHZ_NONE, 0,

RPC_C_AUTHN_LEVEL_PKT,

RPC_C_IMP_LEVEL_IDENTIFY,

pcai, EOAC_NONE);

// dispatch request

switch (action)

{

case ACTION_CHAT:

Chat(wszSessionName, pcsm, pcai, bAnonymous);

break;

case ACTION_DELETE_SESSION:

Delete(wszSessionName, pcsm);

break;

case ACTION_LIST_SESSION_NAMES:

List(pcsm);

break;

default:

Usage();

}

// release session manager

pcsm->Release();

}

}

CoUninitialize();

return hr;

}

ChatSession.h

/////////////////////////////////////////////////////

//

// ChatSession.h

//

// Copyright 1997, Don Box/Addison Wesley

//

// This code accompanies the book "The Component

// Object Model" from Addison Wesley. Blah blah blah

//

//

#ifndef _CHATSESSION_H

#define _CHATSESSION_H

// this pragma shuts up the compiler warnings due to

// the pre MSC11SP1 debugger choking on long template names.

#pragma warning(disable:4786)

#define _WIN32_WINNT 0x403

#include <windows.h>

#include <map>

#include <vector>

#include <string>

using namespace std;

// bring in IDL-generated interface definitions

#include «..\include\COMChat.h»

// this class models a particular chat session

class ChatSession : public IChatSession

{

friend class StatementEnumerator;

LONG m_cRef;

CRITICAL_SECTION m_csStatementLock;

CRITICAL_SECTION m_csAdviseLock;

OLECHAR m_wszSessionName[1024];

bool m_bIsDeleted;

bool m_bAllowAnonymousAccess;

vector<wstring> m_statements;

struct LISTENER

{

LISTENER *pPrev;

LISTENER *pNext;

OLECHAR *pwszUser;

IChatSessionEvents *pItf;

};

LISTENER *m_pHeadListeners;

void SLock(void);

void SUnlock(void);

void ALock(void);

void AUnlock(void);

bool CheckAccess(const OLECHAR *pwszUser);

protected:

virtual ~ChatSession(void);

void Fire_OnNewStatement(const OLECHAR *pwszUser,

const OLECHAR *pwszStatement);

void Fire_OnNewUser(const OLECHAR *pwszUser);

void Fire_OnUserLeft(const OLECHAR *pwszUser);

public:

ChatSession(const OLECHAR *pwszSessionName,

bool bAllowAnonymousAccess);

void Disconnect(void);

// IUnknown methods

STDMETHODIMP QueryInterface(REFIID riid, void **ppv);

STDMETHODIMP_(ULONG) AddRef(void);

STDMETHODIMP_(ULONG) Release(void);

// IChatSession methods

STDMETHODIMP get_SessionName(OLECHAR **ppwsz);

STDMETHODIMP Say(const OLECHAR *pwszStatement);

STDMETHODIMP GetStatements(IEnumString **ppes);

STDMETHODIMP Advise(IChatSessionEvents *pEventSink,

DWORD *pdwReg);

STDMETHODIMP Unadvise(DWORD dwReg);

};

// this class enumerates the statements of a session

class StatementEnumerator : public IEnumString

{

LONG m_cRef;

ChatSession *m_pThis;

vector<wstring>::iterator m_cursor;

CRITICAL_SECTION m_csLock;

protected:

void Lock(void);

void Unlock(void);

virtual ~StatementEnumerator(void);

public:

StatementEnumerator(ChatSession *pThis);

// IUnknown methods

STDMETHODIMP QueryInterface(REFIID riid, void **ppv);

STDMETHODIMP_(ULONG) AddRef(void);

STDMETHODIMP_(ULONG) Release(void);

// IEnumString methods

STDMETHODIMP Next(ULONG cElems, OLECHAR **rgElems,

ULONG *pcFetched);

STDMETHODIMP Skip(ULONG cElems);

STDMETHODIMP Reset(void);

STDMETHODIMP Clone(IEnumString **ppes);

};

// this class models the management of chat sessions

// and acts as the class object for CLSID_ChatSession

class ChatSessionClass : public IChatSessionManager,

public IExternalConnection

{

friend class SessionNamesEnumerator;

typedef map<wstring, ChatSession *> SESSIONMAP;

LONG m_cStrongLocks;

SESSIONMAP m_sessions;

CRITICAL_SECTION m_csSessionLock;

void Lock(void);

void Unlock(void);

bool CheckAccess(const OLECHAR *pwszUser);

public:

virtual ~ChatSessionClass(void);

ChatSessionClass(void);

// IUnknown methods

STDMETHODIMP QueryInterface(REFIID riid, void **ppv);

STDMETHODIMP_(ULONG) AddRef(void);

STDMETHODIMP_(ULONG) Release(void);

// IExternalConnection methods

STDMETHODIMP_(DWORD) AddConnection(DWORD extconn, DWORD);

STDMETHODIMP_(DWORD) ReleaseConnection(DWORD extconn, DWORD,

BOOL bLastReleaseKillsStub);

// IChatSessionManager methods

STDMETHODIMP GetSessionNames(IEnumString **ppes);

STDMETHODIMP FindSession(const OLECHAR *pwszSessionName,

BOOL bDontCreate,

BOOL bAllowAnonymousAccess,

IChatSession **ppcs);

STDMETHODIMP DeleteSession(const OLECHAR *pwszSessionName);

};

// this class enumerates the session names of a server

class SessionNamesEnumerator : public IEnumString

{

LONG m_cRef;

vector<wstring> *m_pStrings;

SessionNamesEnumerator *m_pCloneSource;

vector<wstring>::iterator m_cursor;

CRITICAL_SECTION m_csLock;

protected:

vector<wstring>& Strings(void);

void Lock(void);

void Unlock(void);

virtual ~SessionNamesEnumerator(void);

public:

SessionNamesEnumerator(ChatSessionClass *pSessionClass);

SessionNamesEnumerator(SessionNamesEnumerator *pCloneSource);

// IUnknown methods

STDMETHODIMP QueryInterface(REFIID riid, void **ppv);

STDMETHODIMP_(ULONG) AddRef(void);

STDMETHODIMP_(ULONG) Release(void);

// IEnumString methods

STDMETHODIMP Next(ULONG cElems, OLECHAR **rgElems,

ULONG *pcFetched);

STDMETHODIMP Skip(ULONG cElems);

STDMETHODIMP Reset(void);

STDMETHODIMP Clone(IEnumString **ppes);

};

#endif

ChatSession.cpp

/////////////////////////////////////////////////////

//

// ChatSession.cpp

//

// Copyright 1997, Don Box/Addison Wesley

//

// This code accompanies the book "The Component

// Object Model" from Addison Wesley. Blah blah blah

//

//

#include «ChatSession.h»

#include <iaccess.h>

// these routines are defined in svc.cpp to

// control server lifetime

extern void ModuleLock(void);

extern void ModuleUnlock(void);

// these access control objects are created

// in svc.cpp to control various privileged

// operations. Most operations in this class

// are non-privileged, so anyone can get in.

extern IAccessControl *g_pacUsers;

extern IAccessControl *g_pacAdmins;

// utility functions /////////////////////////

// duplicate an OLECHAR * using CoTaskMemAlloc

OLECHAR *OLESTRDUP(const OLECHAR *pwsz)

{

DWORD cb = sizeof(OLECHAR)*(wcslen(pwsz) + 1);

OLECHAR *pwszResult = (OLECHAR*)CoTaskMemAlloc(cb);

if (pwszResult)

wcscpy(pwszResult, pwsz);

return pwszResult;

}

// get the caller's username (or «anonymous» if

// no authentication was specified by the caller).

OLECHAR *GetCaller(void)

{

OLECHAR *pwsz = 0;

HRESULT hr = CoQueryClientBlanket(0,0,0,0,0,(void**)&pwsz,0);

if (SUCCEEDED(hr))

return OLESTRDUP(pwsz);

else

return OLESTRDUP(OLESTR(«anonymous»));

}

// class ChatSession ///////////////////////////////

ChatSession::ChatSession(const OLECHAR *pwszSessionName,

bool bAllowAnonymousAccess)

: m_cRef(0),

m_bAllowAnonymousAccess(bAllowAnonymousAccess),

m_pHeadListeners(0)

{

wcscpy(m_wszSessionName, pwszSessionName);

InitializeCriticalSection(&m_csStatementLock);

InitializeCriticalSection(&m_csAdviseLock);

}

ChatSession::~ChatSession(void)

{

DeleteCriticalSection(&m_csStatementLock);

DeleteCriticalSection(&m_csAdviseLock);

// tear down connected listeners

while (m_pHeadListeners)

{

LISTENER *pThisNode = m_pHeadListeners;

if (pThisNode->pItf)

pThisNode->pItf->Release();

if (pThisNode->pwszUser)

CoTaskMemFree(pThisNode->pwszUser);

m_pHeadListeners = pThisNode->pNext;

delete pThisNode;

}

}

// helper methods ///////////

void ChatSession::Disconnect(void)

{

CoDisconnectObject(this, 0);

// tear down connected listeners

ALock();

while (m_pHeadListeners)

{

LISTENER *pThisNode = m_pHeadListeners;

if (pThisNode->pItf)

pThisNode->pItf->Release();

if (pThisNode->pwszUser)

CoTaskMemFree(pThisNode->pwszUser);

m_pHeadListeners = pThisNode->pNext;

delete pThisNode;

}

AUnlock();

}

// send the OnNewStatement event to all listeners

void

ChatSession::Fire_OnNewStatement(const OLECHAR *pwszUser,

const OLECHAR *pwszStatement)

{

ALock();

for (LISTENER *pNode = m_pHeadListeners;

pNode != 0; pNode = pNode->pNext)

{

if (pNode->pItf)

pNode->pItf->OnNewStatement(pwszUser, pwszStatement);

}

AUnlock();

}

// send the OnNewUser event to all listeners

void

ChatSession::Fire_OnNewUser(const OLECHAR *pwszUser)

{

ALock();

for (LISTENER *pNode = m_pHeadListeners;

pNode != 0; pNode = pNode->pNext)

{

if (pNode->pItf)

pNode->pItf->OnNewUser(pwszUser);

}

AUnlock();

}

// send the OnUserLeft event to all listeners

void

ChatSession::Fire_OnUserLeft(const OLECHAR *pwszUser)

{

ALock();

for (LISTENER *pNode = m_pHeadListeners;

pNode != 0; pNode = pNode->pNext)

{

if (pNode->pItf)

pNode->pItf->OnUserLeft(pwszUser);

}

AUnlock();

}

// lock wrappers

void ChatSession::SLock(void)

{

EnterCriticalSection(&m_csStatementLock);

}

void ChatSession::SUnlock(void)

{

LeaveCriticalSection(&m_csStatementLock);

}

void ChatSession::ALock(void)

{

EnterCriticalSection(&m_csAdviseLock);

}

void ChatSession::AUnlock(void)

{

LeaveCriticalSection(&m_csAdviseLock);

}

// helper method to check access to Say method

bool

ChatSession::CheckAccess(const OLECHAR *pwszUser)

{

if (wcscmp(pwszUser, L"anonymous") == 0)

return m_bAllowAnonymousAccess;

// form trustee from caller and use Access Control

// object hardwired to COMChat Users group

TRUSTEEW trustee = {

0, NO_MULTIPLE_TRUSTEE, TRUSTEE_IS_NAME,

TRUSTEE_IS_USER,

const_cast<OLECHAR*>(pwszUser)

};

BOOL bIsAllowed;

HRESULT hr = g_pacUsers->IsAccessAllowed(&trustee,0,

COM_RIGHTS_EXECUTE,

&bIsAllowed);

return SUCCEEDED(hr) && bIsAllowed != FALSE;

}

// IUnknown methods

STDMETHODIMP

ChatSession::QueryInterface(REFIID riid, void **ppv)

{

if (riid == IID_IUnknown)

*ppv = static_cast<IChatSession*>(this);

else if (riid == IID_IChatSession)

*ppv = static_cast<IChatSession*>(this);

else

return (*ppv = 0), E_NOINTERFACE;

reinterpret_cast<IUnknown*>(*ppv)->AddRef();

return S_OK;

}

STDMETHODIMP_(ULONG)

ChatSession::AddRef(void)

{

ModuleLock();

return InterlockedIncrement(&m_cRef);

}

STDMETHODIMP_(ULONG)

ChatSession::Release(void)

{

LONG res = InterlockedDecrement(&m_cRef);

if (res == 0)

delete this;

ModuleUnlock();

return res;

}

// IChatSession methods

STDMETHODIMP

ChatSession::get_SessionName(OLECHAR **ppwsz)