Leaked source code of windows server 2003
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178 lines
4.9 KiB

/*++
Copyright (C) 1997-2000 Microsoft Corporation
Module Name:
MMFARENA.H
Abstract:
CArena derivative based on memory mapped files.
History:
a-raymcc 23-Apr-96 Created
paulall 23-Mar-98 Re-worked
--*/
#ifndef _MMFARENA_H_
#define _MMFARENA_H_
#include "corepol.h"
#include "FlexArry.h"
#if defined _WIN32
#define MMF_DELETED_MASK 0x80000000
#define MMF_REMOVE_DELETED_MASK 0x7FFFFFFF
#define MMF_DEBUG_DELETED_TAG 0xFFFFFFFF
#define MMF_DEBUG_INUSE_TAG 0xFEFEFEFE
#elif defined _WIN64
#define MMF_DELETED_MASK 0x8000000000000000
#define MMF_REMOVE_DELETED_MASK 0x7FFFFFFFFFFFFFFF
#define MMF_DEBUG_DELETED_TAG 0xFFFFFFFFFFFFFFFF
#define MMF_DEBUG_INUSE_TAG 0xFEFEFEFEFEFEFEFE
#endif
struct MMFOffsetItem;
#include "corex.h"
class DATABASE_FULL_EXCEPTION : public CX_Exception
{
};
//***************************************************************************
//
// struct MMF_ARENA_HEADER
//
// Root structure for MMF Arena. This is recorded on the disk
// image at the very beginning of the file.
//
//***************************************************************************
#pragma pack(4) // Require fixed aligment.
typedef struct
{
// Version used to create file
// vvvvvv MUST BE FIRST VALUE vvvvvvv
DWORD m_dwVersion; // <<<<<< MUST BE FIRST VALUE!
// ^^^^^^ MUST BE FIRST VALUE ^^^^^^^
DWORD m_dwGranularity; // Granularity of allocation
DWORD m_dwCurrentSize; // Current size of heap
DWORD m_dwMaxSize; // Max heap size, -1= no limit
DWORD m_dwGrowBy; // Bytes to grow by during out-of-heap
DWORD_PTR m_dwHeapExtent; // First unused address
DWORD_PTR m_dwEndOfHeap; // Last valid address + 1
DWORD_PTR m_dwFreeList; // NULL if empty
DWORD_PTR m_dwRootBlock; // Root block
DWORD m_dwSizeOfFirstPage; //Size of the first block
} MMF_ARENA_HEADER;
typedef struct
{
DWORD m_dwSize; //Size of block. Highest bit set when deleted.
} MMF_BLOCK_HEADER;
typedef struct
{
DWORD_PTR m_dwFLback; //previous free block in the chain, NULL if not deleted
DWORD m_dwCheckBlock[2];
} MMF_BLOCK_TRAILER;
typedef struct
{
DWORD_PTR m_dwFLnext; //Next free block in the chain
} MMF_BLOCK_DELETED;
typedef struct
{
DWORD m_dwSize; //Size of page
} MMF_PAGE_HEADER; //Page header... not there for first page.
#pragma pack() // Restore previous aligment.
//***************************************************************************
//
// class CMMFArena2
//
// Implements an offset-based heap over a memory-mapped file.
//
//***************************************************************************
class CMMFArena2
{
DWORD m_dwStatus;
HANDLE m_hFile;
MMF_ARENA_HEADER *m_pHeapDescriptor;
DWORD m_dwCursor;
DWORD m_dwMappingGranularity;
DWORD m_dwMaxPageSize;
CFlexArray m_OffsetManager;
//Retrieves the size of the block from the header and removes the deleted bit
DWORD GetSize(MMF_BLOCK_HEADER *pBlock) { return pBlock->m_dwSize & MMF_REMOVE_DELETED_MASK; }
//Validates a pointer
BOOL ValidateBlock(DWORD_PTR dwBlock)
#if (defined DEBUG || defined _DEBUG)
;
#pragma message("MMF heap validation enabled.")
#else
{ return TRUE;}
#endif
MMFOffsetItem *OpenBasePage(DWORD &dwSizeOfRepository);
MMFOffsetItem *OpenExistingPage(DWORD_PTR dwBaseOffset);
void ClosePage(MMFOffsetItem *pOffsetItem);
void CloseAllPages();
public:
enum { create_new, use_existing };
// Constructor.
CMMFArena2();
// Destructor.
~CMMFArena2();
//Methods to open an MMF
bool LoadMMF(const TCHAR *pszFile);
DWORD Size(DWORD_PTR dwBlock);
DWORD GetVersion() { return (m_pHeapDescriptor? m_pHeapDescriptor->m_dwVersion : 0); }
DWORD GetStatus() { return m_dwStatus; }
//Given an offset, returns a fixed up pointer
LPBYTE OffsetToPtr(DWORD_PTR dwOffset);
//Given a pointer, returns an offset from the start of the MMF
DWORD_PTR PtrToOffset(LPBYTE pBlock);
MMF_ARENA_HEADER *GetMMFHeader() { return m_pHeapDescriptor; }
};
//***************************************************************************
//
// Fixup helpers.
//
// These are all strongly type variations of the same thing: they fix
// up the based ptr to a dereferenceable pointer or take the ptr and
// fix it back down to an offset.
//
//***************************************************************************
extern CMMFArena2* g_pDbArena;
template <class T> T Fixup(T ptr)
{ return T(g_pDbArena->OffsetToPtr(DWORD_PTR(ptr))); }
template <class T> T Fixdown(T ptr)
{ return T(g_pDbArena->PtrToOffset(LPBYTE(ptr))); }
#endif