275 lines
8.2 KiB
C++
275 lines
8.2 KiB
C++
//+---------------------------------------------------------------------------
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//
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// Microsoft Windows
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// Copyright (C) Microsoft Corporation, 1995-2000.
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//
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// File: SeqSer.cxx
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//
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// Contents: Sequential cursor for serial (unsorted) results.
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//
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// Classes: CSequentialSerial
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//
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// History: 05-Jun-95 KyleP Created
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// 14-JAN-97 KrishnaN Undefined CI_INETSRV and related changes
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//
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//----------------------------------------------------------------------------
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#include <pch.cxx>
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#pragma hdrstop
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#include "seqser.hxx"
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#include "rowman.hxx"
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// Rowset object Interfaces that support Ole DB error objects
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static const IID * apRowsetErrorIFs[] =
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{
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&IID_IAccessor,
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&IID_IColumnsInfo,
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&IID_IConvertType,
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&IID_IRowset,
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&IID_IRowsetInfo,
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//&IID_IRowsetWatchRegion,
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//&IID_IRowsetAsynch,
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&IID_IRowsetQueryStatus,
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//&IID_IColumnsRowset,
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&IID_IConnectionPointContainer,
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&IID_IRowsetIdentity,
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//&IID_IRowsetLocate,
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//&IID_IRowsetResynch,
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//&IID_IRowsetScroll,
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//&IID_IRowsetUpdate,
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//&IID_ISupportErrorInfo
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};
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static const ULONG cRowsetErrorIFs = sizeof(apRowsetErrorIFs)/sizeof(apRowsetErrorIFs[0]);
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//+---------------------------------------------------------------------------
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//
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// Member: CSequentialSerial::CSequentialSerial, public
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//
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// Synopsis: Constructor.
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//
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// Arguments: [pUnkOuter] -- outer unknown
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// [ppMyUnk] -- OUT: on return, filled with pointer to my
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// non-delegating IUnknown
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// [aChild] -- Child rowset(s)
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// [cChild] -- Count of rowsets in [aChild]
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// [Props] -- Rowset properties.
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// [cCol] -- Number of original columns.
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//
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// History: 05-Jun-95 KyleP Created.
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//
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//----------------------------------------------------------------------------
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CSequentialSerial::CSequentialSerial( IUnknown * pUnkOuter,
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IUnknown ** ppMyUnk,
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IRowset ** aChild,
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unsigned cChild,
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CMRowsetProps const & Props,
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unsigned cCol,
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CAccessorBag & aAccessors) :
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CDistributedRowset( pUnkOuter, ppMyUnk,
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aChild, cChild, Props, cCol,
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aAccessors, _DBErrorObj ),
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#pragma warning(disable : 4355) // 'this' in a constructor
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_DBErrorObj(* (IUnknown *) (IRowset *)this, _mutex ),
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#pragma warning(default : 4355) // 'this' in a constructor
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_iChild( 0 )
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{
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_DBErrorObj.SetInterfaceArray(cRowsetErrorIFs, apRowsetErrorIFs);
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}
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//+---------------------------------------------------------------------------
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//
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// Member: CSequentialSerial::~CSequentialSerial, public
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//
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// Synopsis: Virtual destructor.
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//
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// History: 05-Jun-95 KyleP Created.
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//
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//----------------------------------------------------------------------------
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CSequentialSerial::~CSequentialSerial()
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{
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}
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//+---------------------------------------------------------------------------
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//
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// Member: CSequentialSerial::_GetNextRows, protected
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//
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// Synopsis: Sequentially fetch rows
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//
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// Arguments: [hChapter] -- Chapter
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// [cRowsToSkip] -- Skip this many rows before beginning.
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// [cRows] -- Try to fetch this many rows.
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// [pcRowsObtained] -- Actually fetched this many.
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// [pphRows] -- Store HROWs here. Allocate memory if
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// [pphRows] is zero.
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//
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// History: 07-Apr-95 KyleP Created.
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//
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// Notes: Since every child cursor was given the same bindings, this
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// method can be resolved by any of the child cursors.
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//
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// Notes: Need to have Ole DB error handling here because we are translating
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// errors.
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//
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//----------------------------------------------------------------------------
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SCODE CSequentialSerial::_GetNextRows( HCHAPTER hChapter,
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DBROWOFFSET cRowsToSkip,
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DBROWCOUNT cRows,
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DBCOUNTITEM * pcRowsObtained,
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HROW * * pphRows )
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{
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_DBErrorObj.ClearErrorInfo();
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SCODE sc = S_OK;
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Win4Assert( 0 == hChapter && "Chapter support not yet implemented" );
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if (!pcRowsObtained || !pphRows)
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{
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vqDebugOut(( DEB_IERROR, "CSequentialSerial::GetNextRows: Invalid parameter(s).\n" ));
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return _DBErrorObj.PostHResult(E_INVALIDARG, IID_IRowset);
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}
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*pcRowsObtained = 0;
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if (0 == cRows) // nothing to fetch
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return S_OK;
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TRY
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{
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//
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// Don't support backwards fetch.
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//
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if ( cRows < 0 || cRowsToSkip < 0 )
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{
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return _DBErrorObj.PostHResult(DB_E_CANTFETCHBACKWARDS, IID_IRowset);
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}
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//
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// We may have to allocate memory, if the caller didn't.
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//
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XCoMem<HROW> xmem;
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if ( 0 == *pphRows )
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{
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xmem.Set( (HROW *)CoTaskMemAlloc( (ULONG) ( cRows * sizeof(HROW) ) ) );
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*pphRows = xmem.GetPointer();
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}
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if ( 0 == *pphRows )
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{
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vqDebugOut(( DEB_ERROR, "CSequentialSerial::GetNextRows: Out of memory.\n" ));
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THROW( CException( E_OUTOFMEMORY ) );
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}
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//
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// Fetch from current child.
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//
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ULONG cTotalRowsObtained = 0;
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while ( cTotalRowsObtained < (ULONG)cRows )
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{
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if ( _iChild >= _cChild )
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{
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sc = DB_S_ENDOFROWSET;
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break;
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}
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DBCOUNTITEM cRowsObtained;
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HROW * pStart = *pphRows + cTotalRowsObtained;
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sc = _aChild[_iChild]->GetNextRows( hChapter,
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cRowsToSkip,
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cRows - cTotalRowsObtained,
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&cRowsObtained,
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&pStart );
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Win4Assert( pStart == *pphRows + cTotalRowsObtained );
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cRowsToSkip = 0;
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if ( FAILED(sc) )
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{
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vqDebugOut(( DEB_ERROR, "Error 0x%x calling IRowset::GetNextRows\n", sc ));
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//
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// If we already have some rows, then we can't 'unfetch' them, so we have
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// to mask this error. Presumably it won't be transient and we'll get it
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// again later.
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//
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if ( cTotalRowsObtained > 0 )
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{
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sc = DB_S_ROWLIMITEXCEEDED;
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}
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break;
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}
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//
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// Convert HROWs into distributed HROWs.
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//
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for ( unsigned i = 0; i < cRowsObtained; i++ )
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{
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(*pphRows)[cTotalRowsObtained] = _RowManager.Add( _iChild, pStart[i] );
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cTotalRowsObtained++;
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}
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//
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// May have to move to next child cursor.
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//
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if ( sc == DB_S_ENDOFROWSET )
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{
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_iChild++;
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}
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else if ( 0 == cRowsObtained )
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{
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Win4Assert( ( DB_S_ROWLIMITEXCEEDED == sc ) ||
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( DB_S_STOPLIMITREACHED == sc ) );
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break;
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}
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}
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*pcRowsObtained = cTotalRowsObtained;
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xmem.Acquire();
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}
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CATCH( CException, e )
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{
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sc = e.GetErrorCode();
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}
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END_CATCH
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if (FAILED(sc))
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_DBErrorObj.PostHResult(sc, IID_IRowset);
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return sc;
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} //_GetNextRows
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//+---------------------------------------------------------------------------
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//
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// Member: CSequentialSerial::RestartPosition, public
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//
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// Synopsis: Reset cursor for GetNextRows
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//
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// Arguments: [hChapter] -- Chapter
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//
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// History: 22 Sep 98 VikasMan Created.
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//
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//----------------------------------------------------------------------------
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STDMETHODIMP CSequentialSerial::RestartPosition( HCHAPTER hChapter )
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{
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_iChild = 0;
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return CDistributedRowset::RestartPosition( hChapter );
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}
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