Сущность технологии СОМ. Библиотека программиста
Шрифт:
{
m_pThis->Release;
DeleteCriticalSection(&m_csLock);
}
// lock helpers (note that ChatSession is locked
// simultaneously)
void
StatementEnumerator::Lock(void)
{
EnterCriticalSection(&m_csLock);
m_pThis->SLock;
}
void
StatementEnumerator::Unlock(void)
{
LeaveCriticalSection(&m_csLock);
m_pThis->SUnlock;
}
// IUnknown methods
STDMETHODIMP
StatementEnumerator::QueryInterface(REFIID riid, void **ppv)
{
if (riid == IID_IUnknown)
*ppv = static_cast<IEnumString*>(this);
else if (riid == IID_IEnumString)
*ppv = static_cast<IEnumString*>(this);
else
return (*ppv = 0), E_NOINTERFACE;
reinterpret_cast<IUnknown*>(*ppv)->AddRef;
return S_OK;
}
STDMETHODIMP_(ULONG)
StatementEnumerator::AddRef(void)
{
return InterlockedIncrement(&m_cRef);
}
STDMETHODIMP_(ULONG)
StatementEnumerator::Release(void)
{
LONG res = InterlockedDecrement(&m_cRef);
if (res == 0)
delete this;
return res;
}
// IEnumString methods
STDMETHODIMP
StatementEnumerator::Next(ULONG cElems, OLECHAR **rgElems,
ULONG *pcFetched)
{
if (pcFetched == 0 && cElems > 1)
return E_INVALIDARG;
ZeroMemory(rgElems, sizeof(OLECHAR*) * cElems);
Lock;
ULONG cActual = 0;
while (cActual < cElems
&& m_cursor != m_pThis->m_statements.end)
{
if (rgElems[cActual] = OLESTRDUP((*m_cursor).c_str))
{
m_cursor++;
cActual++;
}
else // allocation error, unwind
{
while (cActual > 0)
{
cActual–;
CoTaskMemFree(rgElems[cActual]);
rgElems[cActual] = 0;
}
break;
}
}
Unlock;
if (pcFetched)
*pcFetched = cActual;
return cElems == cActual ? S_OK : S_FALSE;
}
STDMETHODIMP
StatementEnumerator::Skip(ULONG cElems)
{
Lock;
ULONG cActual = 0;
while (cActual < cElems
&& m_cursor != m_pThis->m_statements.end)
{
m_cursor++;
cActual++;
}
Unlock;
return cElems == cActual ? S_OK : S_FALSE;
}
STDMETHODIMP
StatementEnumerator::Reset(void)
{
Lock;
m_cursor = m_pThis->m_statements.begin;
Unlock;
return S_OK;
}
STDMETHODIMP
StatementEnumerator::Clone(IEnumString **ppes)
{
if (ppes == 0)
return E_INVALIDARG;
if (*ppes = new StatementEnumerator(m_pThis))
return S_OK;
return E_OUTOFMEMORY;
}
// class ChatSessionClass /////////////////////
ChatSessionClass::ChatSessionClass(void)
: m_cStrongLocks(0)
{
InitializeCriticalSection(&m_csSessionLock);
}
ChatSessionClass::~ChatSessionClass(void)
{
DeleteCriticalSection(&m_csSessionLock);
}
void
ChatSessionClass::Lock(void)
{
EnterCriticalSection(&m_csSessionLock);
}
void
ChatSessionClass::Unlock(void)
{
LeaveCriticalSection(&m_csSessionLock);
}
// helper method to protect access to DeleteSession
// to only allow COMChat Admins to delete groups
bool
ChatSessionClass::CheckAccess(const OLECHAR *pwszUser)
{
if (wcscmp(pwszUser, L"anonymous") == 0)
return false;
TRUSTEEW trustee = {
0, NO_MULTIPLE_TRUSTEE, TRUSTEE_IS_NAME,
TRUSTEE_IS_USER, const_cast<OLECHAR*>(pwszUser)
};
BOOL bIsAllowed;
HRESULT hr = g_pacAdmins->IsAccessAllowed(&trustee,0,
COM_RIGHTS_EXECUTE,
&bIsAllowed);
if (FAILED(hr))
bIsAllowed = false;
return SUCCEEDED(hr) && bIsAllowed != FALSE;
}
// IUnknown methods
STDMETHODIMP
ChatSessionClass::QueryInterface(REFIID riid, void **ppv)
{
if (riid == IID_IUnknown)
*ppv = static_cast<IChatSessionManager*>(this);
else if (riid == IID_IChatSessionManager)
*ppv = static_cast<IChatSessionManager*>(this);
else if (riid == IID_IExternalConnection)
*ppv = static_cast<IExternalConnection*>(this);
else
return (*ppv = 0), E_NOINTERFACE;
reinterpret_cast<IUnknown*>(*ppv)->AddRef;
return S_OK;
}
STDMETHODIMP_(ULONG)
ChatSessionClass::AddRef(void)
{
return 2;
}
STDMETHODIMP_(ULONG)
ChatSessionClass::Release(void)
{
return 1;
}
// IExternalConnection methods
STDMETHODIMP_(DWORD)
ChatSessionClass::AddConnection(DWORD extconn, DWORD)
{
if (extconn & EXTCONN_STRONG)
{
ModuleLock;
return InterlockedIncrement(&m_cStrongLocks);
}
return 0;
}
STDMETHODIMP_(DWORD)
ChatSessionClass::ReleaseConnection(DWORD extconn, DWORD,
BOOL bLastReleaseKillsStub)
{
if (extconn & EXTCONN_STRONG)
{
LONG res = InterlockedDecrement(&m_cStrongLocks);
if (res == 0 && bLastReleaseKillsStub)
CoDisconnectObject(
static_cast<IExternalConnection*>(this), 0);
ModuleUnlock;
return res;
}
return 0;
}
// IChatSessionManager methods
STDMETHODIMP
ChatSessionClass::GetSessionNames(IEnumString **ppes)
{
if (ppes == 0)
return E_INVALIDARG;
if (*ppes = new SessionNamesEnumerator(this))
{
(*ppes)->AddRef;
return S_OK;
}
else