Сущность технологии СОМ. Библиотека программиста

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(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(this);

else if (riid == IID_IChatSession)

*ppv = static_cast(this);

else

return (*ppv = 0), E_NOINTERFACE;

reinterpret_cast(*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)

{

if (!ppwsz)

return E_INVALIDARG;

else if ((*ppwsz = OLESTRDUP(m_wszSessionName)) == 0)

return E_OUTOFMEMORY;

return S_OK;

}

STDMETHODIMP

ChatSession::Say(const OLECHAR *pwszStatement)

{

HRESULT hr = S_OK;

// protect access to method

OLECHAR *pwszUser = GetCaller;

if (pwszUser && CheckAccess(pwszUser))

{

SLock;

try

{

wstring s = pwszUser;

s += L":";

s += pwszStatement;

m_statements.push_back(s);

}

catch(...)

{

hr = E_OUTOFMEMORY;

}

SUnlock;

if (SUCCEEDED(hr))

Fire_OnNewStatement(pwszUser, pwszStatement);

}

else

hr = E_ACCESSDENIED;

CoTaskMemFree(pwszUser);

return hr;

}

STDMETHODIMP

ChatSession::GetStatements(IEnumString **ppes)

{

if (ppes == 0)

return E_INVALIDARG;

*ppes = new StatementEnumerator(this);

if (*ppes == 0)

return E_OUTOFMEMORY;

(*ppes)->AddRef;

return S_OK;

}

STDMETHODIMP

ChatSession::Advise(IChatSessionEvents *pEventSink,

DWORD *pdwReg)

{

HRESULT hr = S_OK;

if (pEventSink == 0 || pdwReg == 0)

return E_INVALIDARG;

LISTENER *pNew = new LISTENER;

if (pNew == 0)

return E_OUTOFMEMORY;

OLECHAR *pwszUser = GetCaller;

if (pwszUser)

{

Fire_OnNewUser(pwszUser);

ALock;

pNew->pwszUser = pwszUser;

if (pNew->pItf = pEventSink)

pEventSink->AddRef;

pNew->pNext = m_pHeadListeners;

if (m_pHeadListeners)

m_pHeadListeners->pPrev = pNew;

pNew->pPrev = 0;

m_pHeadListeners = pNew;

AUnlock;

}

else

{

delete pNew;

return E_OUTOFMEMORY;

}

*pdwReg = reinterpret_cast(pNew);

return hr;

}

STDMETHODIMP

ChatSession::Unadvise(DWORD dwReg)

{

if (dwReg == 0)

return E_INVALIDARG;

HRESULT hr = S_OK;

LISTENER *pThisNode = reinterpret_cast(dwReg);

ALock;

if (pThisNode->pPrev)

pThisNode->pPrev->pNext = pThisNode->pNext;

else

m_pHeadListeners = pThisNode->pNext;

if (pThisNode->pNext)

pThisNode->pNext->pPrev = pThisNode->pPrev;

if (pThisNode->pItf)

pThisNode->pItf->Release;

OLECHAR *pwszUser = pThisNode->pwszUser;

delete pThisNode;

AUnlock;

Fire_OnUserLeft(pwszUser);

CoTaskMemFree(pwszUser);

return hr;

}

// class StatementEnumerator ///////////////////

StatementEnumerator::StatementEnumerator(ChatSession *pThis)

: m_cRef(0),

m_pThis(pThis),

m_cursor(pThis->m_statements.begin)

{

m_pThis->AddRef;

InitializeCriticalSection(&m_csLock);

}

StatementEnumerator::~StatementEnumerator(void)

{

m_pThis->Release;

DeleteCriticalSection(&m_csLock);

}

// lock helpers (note that ChatSession is locked