DATASRC.CPP

//-------------------------------------------------------------------- 
// Microsoft OLE DB Sample Provider 
// (C) Copyright 1994 - 1996 Microsoft Corporation.  All Rights Reserved. 
// 
// @doc 
// 
// @module DATASRC.CPP | CDataSource object implementation 
// 
// 
 
// Includes ------------------------------------------------------------------ 
 
#include "headers.h" 
 
 
// Code ---------------------------------------------------------------------- 
 
// CDataSource::CDataSource -------------------------------------------------- 
// 
// @mfunc Constructor for this class 
// 
// @rdesc NONE 
// 
CDataSource::CDataSource 
    ( 
    LPUNKNOWN pUnkOuter         //@parm IN | Outer Unkown Pointer 
    ) 
{ 
 
    //  Initialize simple member vars 
    m_cRef              = 0L; 
    m_pUnkOuter         = pUnkOuter; 
    *m_szPath           = '\0'; 
    m_fDSOInitialized   = FALSE; 
    m_fDBSessionCreated = FALSE; 
    m_pUtilProp         = NULL; 
 
    //  Initially, NULL all contained interfaces 
    m_pIDBInitialize    = NULL; 
    m_pIDBProperties= NULL; 
    m_pIDBInfo= NULL; 
m_pIDBCreateSession = NULL; 
 
    // Increment global object count. 
    OBJECT_CONSTRUCTED(); 
 
    return; 
} 
 
 
// CDataSource::~CDataSource ------------------------------------------------- 
// 
// @mfunc Destructor for this class 
// 
// @rdesc NONE 
// 
CDataSource:: ~CDataSource 
    ( 
    void 
    ) 
{ 
ULONGulRefCount; 
 
// Decrement the ref count on the data conversion object 
if( g_pIDataConvert ) 
{ 
ulRefCount = g_pIDataConvert->Release(); 
 
// Is it gone for good? 
if( !ulRefCount ) 
g_pIDataConvert = NULL; 
} 
 
    // Free properties management object 
    delete m_pUtilProp; 
 
    //  Free contained interfaces 
    delete m_pIDBInitialize; 
    delete m_pIDBProperties; 
    delete m_pIDBInfo; 
delete m_pIDBCreateSession; 
 
    // Decrement global object count. 
    OBJECT_DESTRUCTED(); 
 
    return; 
} 
 
 
// CDataSource::FInit -------------------------------------------------------- 
// 
// @mfunc Initialize the command Object 
// 
// @rdesc Did the Initialization Succeed 
//      @flag  TRUE | Initialization succeeded 
//      @flag  FALSE | Initialization failed 
// 
BOOL CDataSource::FInit 
    ( 
    void 
    ) 
{ 
HRESULThr; 
    LPUNKNOWN   pIUnknown = (LPUNKNOWN) this; 
 
    if (m_pUnkOuter) 
        pIUnknown = m_pUnkOuter; 
 
// Instantiate the data conversion service object 
if( !g_pIDataConvert ) 
{ 
hr = CoCreateInstance(CLSID_OLEDB_CONVERSIONLIBRARY, 
  NULL, 
  CLSCTX_INPROC_SERVER, 
  IID_IDataConvert, 
  (void **)&g_pIDataConvert); 
if( FAILED(hr) ) 
return FALSE; 
} 
else 
// Already instantiated, increment reference count 
g_pIDataConvert->AddRef(); 
 
    // Allocate properties management object 
    m_pUtilProp = new CUtilProp(); 
 
    //  Allocate contained interface objects 
    m_pIDBInitialize    = new CImpIDBInitialize( this, pIUnknown ); 
    m_pIDBProperties= new CImpIDBProperties( this, pIUnknown ); 
m_pIDBInfo= new CImpIDBInfo( this, pIUnknown ); 
    m_pIDBCreateSession = new CImpIDBCreateSession( this, pIUnknown ); 
 
    return (BOOL) (m_pIDBInitialize && 
   m_pIDBInfo && 
                   m_pIDBProperties&& 
                   m_pIDBCreateSession); 
} 
 
 
// CDataSource::QueryInterface ----------------------------------------------- 
// 
// @mfunc Returns a pointer to a specified interface. Callers use 
// QueryInterface to determine which interfaces the called object 
// supports. 
// 
// @rdesc HRESULT indicating the status of the method 
//      @flag S_OK          | Interface is supported and ppvObject is set. 
//      @flag E_NOINTERFACE | Interface is not supported by the object 
//      @flag E_INVALIDARG  | One or more arguments are invalid. 
// 
STDMETHODIMP CDataSource::QueryInterface 
    ( 
    REFIID riid,    //@parm IN | Interface ID of the interface being queried for. 
    LPVOID * ppv    //@parm OUT | Pointer to interface that was instantiated 
    ) 
{ 
    // Is the pointer bad? 
    if (ppv == NULL) 
        return ResultFromScode( E_INVALIDARG ); 
 
    //  Place NULL in *ppv in case of failure 
    *ppv = NULL; 
 
    //  This is the non-delegating IUnknown implementation 
    if (riid == IID_IUnknown) 
        *ppv = (LPVOID) this; 
    else if (riid == IID_IDBInitialize) 
        *ppv = (LPVOID) m_pIDBInitialize; 
else if (riid == IID_IDBInfo) 
*ppv = (LPVOID) m_pIDBInfo; 
else if (riid == IID_IDBProperties) 
        *ppv = (LPVOID) m_pIDBProperties; 
    else if (riid == IID_IDBCreateSession) 
        *ppv = (LPVOID) m_pIDBCreateSession; 
 
    //  If we're going to return an interface, AddRef it first 
    if (*ppv) 
        { 
        ((LPUNKNOWN) *ppv)->AddRef(); 
        return ResultFromScode( S_OK ); 
        } 
    else 
        return ResultFromScode( E_NOINTERFACE ); 
} 
 
 
// CDataSource::AddRef ------------------------------------------------------- 
// 
// @mfunc Increments a persistence count for the object 
// 
// @rdesc Current reference count 
// 
STDMETHODIMP_( ULONG ) CDataSource::AddRef 
     ( 
     void 
     ) 
{ 
    return ++m_cRef; 
} 
 
 
// CDataSource::Release ------------------------------------------------------ 
// 
// @mfunc Decrements a persistence count for the object and if 
// persistence count is 0, the object destroys itself. 
// 
// @rdesc Current reference count 
// 
STDMETHODIMP_( ULONG ) CDataSource::Release 
     ( 
     void 
     ) 
{ 
    if (!--m_cRef) 
        { 
        delete this; 
        return 0; 
        } 
 
    return m_cRef; 
}