// perform a synchronous read request on this thread.
// Need to hold m_csFile while doing this (done in request object)
HRESULT
CAsyncIo::SyncReadAligned(
LONGLONG llPos,
LONG lLength,
BYTE * pBuffer,
LONG * pcbActual,
PVOID pvContext)
{
CheckPointer(pcbActual,E_POINTER);
if(!IsAligned(llPos) ||
!IsAligned(lLength) ||
!IsAligned((LONG_PTR) pBuffer))
{
return VFW_E_BADALIGN;
}
CAsyncRequest request;
m_pStream->Lock();
HRESULT hr = request.Request(this,
m_pStream,
llPos,
lLength,
TRUE,
pBuffer,
pvContext,
0);
if(SUCCEEDED(hr))
{
hr = request.Complete();
}
m_pStream->Unlock();
// return actual data length
*pcbActual = request.GetActualLength();
return hr;
}
HRESULT
CAsyncIo::SyncReadAligned(
LONGLONG llPos,
LONG lLength,
BYTE* pBuffer,
LONG* pcbActual,
PVOID pvContext
)
{
if (!IsAligned(llPos) ||
!IsAligned(lLength) ||
!IsAligned((LONG) pBuffer)) {
return VFW_E_BADALIGN;
}
CAsyncRequest request;
HRESULT hr = request.Request(
this,
m_pStream,
llPos,
lLength,
TRUE,
pBuffer,
pvContext,
0);
if (FAILED(hr)) {
return hr;
}
hr = request.Complete();
*pcbActual = request.GetActualLength();
return hr;
}
HRESULT
CAsyncIo::WaitForNext(
DWORD dwTimeout,
LPVOID *ppContext,
DWORD * pdwUser,
LONG* pcbActual)
{
*ppContext = NULL;
for (;;) {
if (!m_evDone.Wait(dwTimeout)) {
return VFW_E_TIMEOUT;
}
CAsyncRequest* pRequest = GetDoneItem();
if (pRequest) {
HRESULT hr = pRequest->GetHResult();
if (hr == S_FALSE) {
if ((pRequest->GetActualLength() +
pRequest->GetStart()) == Size()) {
hr = S_OK;
} else {
hr = E_FAIL;
}
}
*pcbActual = pRequest->GetActualLength();
*ppContext = pRequest->GetContext();
*pdwUser = pRequest->GetUser();
delete pRequest;
return hr;
} else {
CAutoLock lck(&m_csLists);
if (m_bFlushing && !m_bWaiting) {
return VFW_E_WRONG_STATE;
}
}
}
}
// wait for the next request to complete
HRESULT
CAsyncIo::WaitForNext(
DWORD dwTimeout,
LPVOID * ppContext,
DWORD_PTR * pdwUser,
LONG * pcbActual)
{
CheckPointer(ppContext,E_POINTER);
CheckPointer(pdwUser,E_POINTER);
CheckPointer(pcbActual,E_POINTER);
// some errors find a sample, others don't. Ensure that
// *ppContext is NULL if no sample found
*ppContext = NULL;
// wait until the event is set, but since we are not
// holding the critsec when waiting, we may need to re-wait
for(;;)
{
if(!m_evDone.Wait(dwTimeout))
{
// timeout occurred
return VFW_E_TIMEOUT;
}
// get next event from list
CAsyncRequest* pRequest = GetDoneItem();
if(pRequest)
{
// found a completed request
// check if ok
HRESULT hr = pRequest->GetHResult();
if(hr == S_FALSE)
{
LONGLONG llBytesToRead = 0, llAvailable = 0;
hr = m_pStream->Length(&llBytesToRead, &llAvailable);
if (SUCCEEDED(hr) &&
(pRequest->GetActualLength() + pRequest->GetStart() == llBytesToRead))
{
// this means the actual length was less than
// requested - may be ok if he aligned the end of file
hr = S_OK;
}
else
{
// it was an actual read error
hr = E_FAIL;
}
}
// return actual bytes read
*pcbActual = pRequest->GetActualLength();
// return his context
*ppContext = pRequest->GetContext();
*pdwUser = pRequest->GetUser();
delete pRequest;
return hr;
}
else
{
// Hold the critical section while checking the list state
CAutoLock lck(&m_csLists);
if(m_bFlushing && !m_bWaiting)
{
// can't block as we are between BeginFlush and EndFlush
// but note that if m_bWaiting is set, then there are some
// items not yet complete that we should block for.
return VFW_E_WRONG_STATE;
}
}
// done item was grabbed between completion and
// us locking m_csLists.
}
}