149 lines
4.4 KiB
C++
149 lines
4.4 KiB
C++
//+---------------------------------------------------------------------------
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//
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// Microsoft Windows
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// Copyright (C) Microsoft Corporation, 1992 - 1992.
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//
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// File: mrshlist.hxx
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//
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// Contents: CMarshalList header
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//
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// Classes: CMarshalList
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//
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// History: 16-Mar-96 HenryLee Created
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//
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//----------------------------------------------------------------------------
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#ifndef __MRSHLIST_HXX__
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#define __MRSHLIST_HXX__
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#define POINTER_IDENTITY
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class CMarshalList; // forward declaration for SAFE macro
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SAFE_DFBASED_PTR(CBasedMarshalListPtr, CMarshalList);
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//+---------------------------------------------------------------------------
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//
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// Class: CMarshalList (ml)
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//
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// Purpose: Maintains a list of marshaled exposed objects that
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// represent the same storage or stream
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//
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// Interface: See below
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//
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// Notes: This class is intended to solve the "pointer identity"
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// problem. When an IStorage or IStream is passed as an
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// [in, out] RPC parameter, two marshal/unmarshalings occur,
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// one for the [in] side, and a reverse marshaling for
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// the [out] side. The previous algorithm always allocated
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// a new exposed object for every unmarshaling, so the
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// pointer going into an [in,out] call isn't the same
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// as the pointer returned from the call.
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//
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// This algorithm links the exposed objects together, each
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// link keyed by the ContextId (ProcessId). When unmarshaling,
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// this list is checked for a valid exposed object that
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// can be reused. If not, then a new exposed object
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// is allocated and inserted into the linked list.
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// Instances of this class must live in shared memory
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// in order for the list to traverse across processes
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//
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// History: 26-Mar-96 HenryLee Created
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//
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//----------------------------------------------------------------------------
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class CMarshalList
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{
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protected:
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inline CMarshalList ();
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inline ~CMarshalList ();
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public:
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inline CMarshalList * GetNextMarshal () const;
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inline void SetNextMarshal (CMarshalList *pml);
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inline ContextId GetContextId () const;
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CMarshalList * FindMarshal (ContextId ctxid) const;
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void AddMarshal (CMarshalList *pml);
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void RemoveMarshal (CMarshalList *pml);
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private:
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CBasedMarshalListPtr _pmlNext;
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ContextId _cntxid;
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};
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//+---------------------------------------------------------------------------
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//
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// Member: CMarshalList::CMarshalList, public
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//
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// Synopsis: Constructor
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//
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// History: 17-Mar-96 HenryLee Created
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//
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//----------------------------------------------------------------------------
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inline CMarshalList::CMarshalList ()
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{
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_pmlNext = P_TO_BP(CBasedMarshalListPtr, this);
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_cntxid = GetCurrentContextId();
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}
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//+---------------------------------------------------------------------------
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//
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// Member: CMarshalList::~CMarshalList, public
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//
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// Synopsis: Destructor
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//
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// History: 17-Mar-96 HenryLee Created
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//
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//----------------------------------------------------------------------------
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inline CMarshalList::~CMarshalList ()
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{
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RemoveMarshal(this);
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}
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//+---------------------------------------------------------------------------
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//
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// Member: CMarshalList::GetNext, public
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//
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// Synopsis: Returns the next element of the list
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//
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// History: 17-Mar-96 HenryLee Created
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//
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//----------------------------------------------------------------------------
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inline CMarshalList *CMarshalList::GetNextMarshal () const
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{
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return BP_TO_P(CMarshalList *, _pmlNext);
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}
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//+---------------------------------------------------------------------------
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//
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// Member: CMarshalList::SetNext, public
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//
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// Synopsis: Assigns the next element of the list
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//
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// History: 17-Mar-96 HenryLee Created
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//
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//----------------------------------------------------------------------------
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inline void CMarshalList::SetNextMarshal (CMarshalList *pml)
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{
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_pmlNext = P_TO_BP(CBasedMarshalListPtr, pml);
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}
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//+---------------------------------------------------------------------------
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//
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// Member: CMarshalList::GetContextId, public
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//
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// Synopsis: Returns the context id of the current element
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//
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// History: 17-Mar-96 HenryLee Created
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//
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//----------------------------------------------------------------------------
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inline ContextId CMarshalList::GetContextId () const
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{
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return _cntxid;
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}
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#endif // #ifndef __MRSHLIST_HXX__
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