seekpt.cpp


//------------------------------------------------------------------------------
// File: SeekPT.cpp
//
// Desc: DirectShow base classes.
//
// Copyright (c) 1992-2001 Microsoft Corporation.  All rights reserved.
//------------------------------------------------------------------------------
 
 
#include "streams.h"
#include "seekpt.h"
 
//==================================================================
// CreateInstance
// This goes in the factory template table to create new instances
// If there is already a mapper instance - return that, else make one
// and save it in a static variable so that forever after we can return that.
//==================================================================
 
CUnknown * CSeekingPassThru::CreateInstance(__inout_opt LPUNKNOWN pUnk, __inout HRESULT *phr)
{
    return new CSeekingPassThru(NAME("Seeking PassThru"),pUnk, phr);
}
 
 
STDMETHODIMP CSeekingPassThru::NonDelegatingQueryInterface(REFIID riid, __deref_out void ** ppv)
{
    if (riid == IID_ISeekingPassThru) {
        return GetInterface((ISeekingPassThru *) this, ppv);
    } else {
        if (m_pPosPassThru &&
            (riid == IID_IMediaSeeking ||
             riid == IID_IMediaPosition)) {
            return m_pPosPassThru->NonDelegatingQueryInterface(riid,ppv);
        } else {
            return CUnknown::NonDelegatingQueryInterface(riid, ppv);
        }
    }
}
 
 
CSeekingPassThru::CSeekingPassThru( __in_opt LPCTSTR pName, __inout_opt LPUNKNOWN pUnk, __inout HRESULT *phr )
                            : CUnknown(pName, pUnk, phr),
                            m_pPosPassThru(NULL)
{
}
 
 
CSeekingPassThru::~CSeekingPassThru()
{
    delete m_pPosPassThru;
}
 
STDMETHODIMP CSeekingPassThru::Init(BOOL bRendererSeeking, IPin *pPin)
{
    HRESULT hr = NOERROR;
    if (m_pPosPassThru) {
        hr = E_FAIL;
    } else {
        m_pPosPassThru =
            bRendererSeeking ?
                new CRendererPosPassThru(
                    NAME("Render Seeking COM object"),
                    (IUnknown *)this,
                    &hr,
                    pPin) :
                new CPosPassThru(
                    NAME("Render Seeking COM object"),
                    (IUnknown *)this,
                    &hr,
                    pPin);
        if (!m_pPosPassThru) {
            hr = E_OUTOFMEMORY;
        } else {
            if (FAILED(hr)) {
                delete m_pPosPassThru;
                m_pPosPassThru = NULL;
            }
        }
    }
    return hr;
}
↑ V668 There is no sense in testing the 'm_pPosPassThru' pointer against null, as the memory was allocated using the 'new' operator. The exception will be generated in the case of memory allocation error.