186 lines
5.6 KiB
C++
186 lines
5.6 KiB
C++
//+---------------------------------------------------------------------------
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//
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// Microsoft Windows
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// Copyright (C) Microsoft Corporation, 1996 - 2000.
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//
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// File: wqiter.hxx
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//
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// Contents: WEB Query iter class
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//
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// History: 96/Jan/3 DwightKr Created
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//
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//----------------------------------------------------------------------------
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#pragma once
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class CWQueryItem;
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class COutputFormat;
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const ULONG ITER_CACHE_SIZE = 20; // A guess at the avg max # rows per page
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const ULONG NUMBER_INLINE_COLS = 10;// Number of output columns to buffer
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// in-line. If cCols > 10, then we'll
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// have to allocate a buffer
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//+---------------------------------------------------------------------------
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//
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// Class: COutputColumn
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//
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// Purpose: The results of a single output column from an OLEDB query.
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//
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// History: 96/Jan/23 DwightKr Created
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//
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//----------------------------------------------------------------------------
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class COutputColumn
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{
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public:
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PROPVARIANT * GetVariant() { return _pVariant; }
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private:
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PROPVARIANT * _pVariant;
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};
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//+---------------------------------------------------------------------------
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//
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// Class CBaseQueryResultsIter - protocol class; all query result iterators
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// must inherit from this class
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//
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//----------------------------------------------------------------------------
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class CBaseQueryResultsIter
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{
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public:
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CBaseQueryResultsIter( CWQueryItem & item,
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HACCESSOR hAccessor,
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ULONG cCols );
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virtual ~CBaseQueryResultsIter();
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virtual void Init( CVariableSet & VariableSet, COutputFormat & outputFormat ) = 0;
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virtual void Next() = 0;
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virtual COutputColumn * GetRowData() = 0;
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BOOL AtEnd() { return _lRecordsToRetrieve == 0 &&
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_iCurrentCachedRow == _cRowsReturnedToCache; }
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LONG GetNextRecordNumber() const { return _lNextRecordNumber; }
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LONG GetFirstRecordNumber() const { return _lFirstRecordNumber; }
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LONG GetMaxRecordsPerPage() const { return _lMaxRecordsPerPage; }
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CVariableSet & GetVariableSet() const { return *_pVariableSet; }
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ULONG GetColumnCount() const { return _cColumns; }
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protected:
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void InitializeLocalVariables( CVariableSet & variableSet,
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COutputFormat & outputFormat );
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HROW _ahCachedRows[ITER_CACHE_SIZE]; // cached rows
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DBCOUNTITEM _cRowsReturnedToCache; // # rows in cache
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ULONG _iCurrentCachedRow; // current row in cache
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CWQueryItem & _item; // Query item we're iterating over
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COutputColumn * _pOutputColumns; // ptr to output columns
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COutputColumn _aOutputColumns[NUMBER_INLINE_COLS];
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HACCESSOR _hAccessor; // Accessor to query results
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LONG _cColumns; // # columns in query results
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LONG _lFirstRecordNumber; // # of first record available
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LONG _lNextRecordNumber; // # of next record available
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LONG _lMaxRecordsPerPage; // Max # records per page
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LONG _lRecordsToRetrieve; // # records remaining to read
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DBROWCOUNT _lTotalMatchedRecords; // # of records matching query
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CVariableSet * _pVariableSet; // Our replaceable parameters
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};
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//+---------------------------------------------------------------------------
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//
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// Class: CQueryResultsIter
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//
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// Purpose: A non-sequential iterator over a CQueryItem's query results
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//
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// History: 96/Jan/23 DwightKr Created
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//
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//----------------------------------------------------------------------------
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class CQueryResultsIter : public CBaseQueryResultsIter
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{
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INLINE_UNWIND(CQueryResultsIter)
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public:
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CQueryResultsIter( CWQueryItem & item,
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IRowsetScroll * pRowsetScroll,
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HACCESSOR hAccessor,
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ULONG cCols );
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~CQueryResultsIter();
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void Init( CVariableSet & VariableSet, COutputFormat & outputFormat );
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void Next();
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COutputColumn * GetRowData();
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private:
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void FillRowsetCache();
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void ReleaseRowsetCache();
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void InitializeLocalVariables( CVariableSet & variableSet,
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COutputFormat & outputFormat );
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IRowsetScroll * _pIRowsetScroll; // Rowset interface
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};
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//+---------------------------------------------------------------------------
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//
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// Class: CSeqQueryResultsIter
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//
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// Purpose: A sequential iterator over a CQueryItem's query results
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//
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// History: 96/Jan/23 DwightKr Created
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//
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//----------------------------------------------------------------------------
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class CSeqQueryResultsIter : public CBaseQueryResultsIter
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{
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INLINE_UNWIND(CSeqQueryResultsIter)
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public:
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CSeqQueryResultsIter( CWQueryItem & item,
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IRowset * pRowset,
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HACCESSOR hAccessor,
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ULONG cCols,
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ULONG ulNextRecordNumber );
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~CSeqQueryResultsIter();
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void Init( CVariableSet & VariableSet, COutputFormat & outputFormat );
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void Next();
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COutputColumn * GetRowData();
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private:
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void FillRowsetCache( ULONG cRowsToSkip );
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void ReleaseRowsetCache();
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void InitializeLocalVariables( CVariableSet & variableSet,
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COutputFormat & outputFormat );
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IRowset * _pIRowset;
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};
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void SetCGIVariables( CVariableSet & variableSet, CWebServer & webServer );
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