CRTSESS.CPP

//-------------------------------------------------------------------- 
// Microsoft OLE DB Sample Provider 
// (C) Copyright 1994 - 1996 Microsoft Corporation.  All Rights Reserved. 
// 
// @doc 
// 
// @module CRTSESS.CPP | IDBCreateSession interface implementation 
// 
 
// Includes ------------------------------------------------------------------ 
 
#include "headers.h" 
 
 
// Code ---------------------------------------------------------------------- 
 
// CImpIDBCreateSession::CreateSession ------------------------------------------------ 
// 
// @mfunc Creates a new DB Session object from the DSO, and returns the 
// requested interface on the newly created object. 
// 
// @rdesc HRESULT 
//      @flag S_OK                  | The method succeeded. 
//      @flag E_INVALIDARG          | ppDBSession was NULL 
//      @flag DB_E_NOAGGREGATION    | pUnkOuter was not NULL (this object does not support 
//                                    being aggregated) 
//      @flag E_FAIL                | Provider-specific error. This provider can only create 
//                                    one DBSession 
//      @flag E_OUTOFMEMORY         | Out of memory 
//      @flag E_NOINTERFACE         | Could not obtain requested interface on DBSession object 
// 
STDMETHODIMP CImpIDBCreateSession::CreateSession 
    ( 
    IUnknown*   pUnkOuter,  //@parm IN | Controlling IUnknown if being aggregated  
    REFIID      riid,       //@parm IN | The ID of the interface  
    IUnknown**  ppDBSession //@parm OUT | A pointer to memory in which to return the interface pointer 
    ) 
{ 
    CDBSession* pDBSession = NULL; 
    HRESULT hr; 
 
    // check in-params and NULL out-params in case of error 
    if (ppDBSession) 
        *ppDBSession = NULL; 
    else 
        return ResultFromScode( E_INVALIDARG ); 
 
    if (pUnkOuter) 
        return ResultFromScode( DB_E_NOAGGREGATION ); 
 
    assert( m_pObj ); 
 
    // this Data Source object can only create 1 DBSession... 
    if (m_pObj->m_fDBSessionCreated) 
        return ResultFromScode( E_FAIL ); 
 
    // open a DBSession object 
    pDBSession = new CDBSession( NULL ); 
    if (!pDBSession) 
        return ResultFromScode( E_OUTOFMEMORY ); 
 
    // initialize the object 
    if (!pDBSession->FInit( m_pObj->m_szPath, m_pObj )) 
        { 
        delete pDBSession; 
        return ResultFromScode( E_FAIL ); 
        } 
 
    // get requested interface pointer on DBSession 
    hr = pDBSession->QueryInterface( riid, (void **) ppDBSession ); 
    if (FAILED( hr )) 
        { 
        delete pDBSession; 
        return ResultFromScode( hr ); 
        } 
 
    // all went well 
    m_pObj->m_fDBSessionCreated = TRUE; 
    return ResultFromScode( S_OK ); 
}