111 lines
3.6 KiB
C++
111 lines
3.6 KiB
C++
//+---------------------------------------------------------------------------
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//
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// Microsoft Windows
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// Copyright (C) Microsoft Corporation, 1995.
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//
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// File: DisAcc.hxx
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//
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// Contents: Distributed accessor class
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//
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// Classes: CDistributedAccessor
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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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#pragma once
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#include "accbase.hxx"
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//+---------------------------------------------------------------------------
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//
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// Class: CDistributedAccessor
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//
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// Purpose: Backing implementation for distributed HACCESSOR
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//
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// History: 05-Jun-95 KyleP Created.
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//
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// Notes: Most columns for a distributed query can just be fetched
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// from the appropriate child accessor. Bookmark is special.
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// a distributed bookmark contains 'hints' from all cursors.
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// It is because of these hints that CDistributedAccessor
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// needs to intercept calls to the child IRowset::GetData.
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//
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//----------------------------------------------------------------------------
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class CDistributedBookmarkAccessor;
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class CDistributedAccessor : public CAccessorBase
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{
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public:
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CDistributedAccessor( IRowset * * const aCursor,
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unsigned cCursor,
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DBACCESSORFLAGS dwAccessorFlags,
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DBCOUNTITEM cBindings,
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DBBINDING const * rgBindings,
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DBLENGTH cbRowWidth,
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DBBINDSTATUS rgStatus[],
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void * pCreator,
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DBBINDING const * rgAllBindings,
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DBCOUNTITEM cAllBindings );
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~CDistributedAccessor();
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SCODE GetBindings( DBACCESSORFLAGS * pdwAccessorFlags,
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DBCOUNTITEM * pcBindings,
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DBBINDING * * prgBindings );
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SCODE GetData( unsigned iChild, HROW hrow, void * pData );
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SCODE GetData( unsigned iChild, HROW * ahrow, void * pData );
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ULONG Release(); // override from base class (AddRef is same)
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void SetupBookmarkAccessor( CDistributedBookmarkAccessor * pDistBmkAcc,
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DBBINDSTATUS rgStatus[],
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DBORDINAL iBookmark,
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DBBKMARK cBookmark );
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private:
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//
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// Just for convenience. These could be passed in on every call.
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//
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IRowset * * const _aCursor;
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unsigned _cCursor;
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IAccessor * * _aIacc; // IAccessor corresponding to each IRowset
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//
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// 'Base' accessor. Everything but bookmark.
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//
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HACCESSOR * _ahaccBase; // One per rowset.
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//
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// Accessor to fetch bookmarks. Offsets increase for each child.
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// Binding may be a composite from several input bindings.
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// For example, if the client requests value (in DBBINDING[i])
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// and then length and status (in DBBINDING[j]) then _bindBmk
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// will fetch value, length, and status.
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//
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CDistributedBookmarkAccessor * _pDistBmkAcc;
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XArray<DBBINDING> _xAllBindings; // all the bindings for this accessor
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DBCOUNTITEM _cAllBindings; // count of all bindings
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DBACCESSORFLAGS _dwAccessorFlags; // Access Flags
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unsigned _cBookmarkOffsets; // Total # of bookmark bindings
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XArray<DBBINDING*> _xBookmarkOffsets;// Bookmark binding offsets into _rgAllBindings
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DBCOUNTITEM _cBookmark;
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};
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