windows-nt/Source/XPSP1/NT/net/qos/psched/sys/refcnt.c

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2020-09-26 03:20:57 -05:00
/*++
Copyright (c) 1996-1999 Microsoft Corporation
Module Name:
refcnt.c
Abstract:
This module exports Reference Counting support functions. By
including a Reference Count Control Block (REF_CNT) in a
dynamic type, and using this API, a Reference scheme can be
implemented for that type.
Author:
Edward Buchwalter (v-edbuc) 14-Aug-1996
Revision History:
Shreedhar Madhavapeddi (ShreeM) 16-April-1999 Adapted for NT and GPC by ShreeM\MBert.
Rajesh Sundaram (rajeshsu) 05-Aug-1999 Adapted for psched.
--*/
//
// Include Files
//
#include "psched.h"
#pragma hdrstop
#define EXPAND_TAG(t) ((CHAR *)(&Tag))[0],((CHAR *)(&Tag))[1],((CHAR *)(&Tag))[2],((CHAR *)(&Tag))[3]
VOID
ReferenceInit
(
IN PREF_CNT pRefCnt,
PVOID InstanceHandle,
VOID (*DeleteHandler)( PVOID , BOOLEAN)
)
/*++
Routine Description:
ReferenceInit initializes and adds one reference to the
supplied Reference Control Block. If provided, an instance
handle and delete handler are saved for use by the ReferenceRemove
function when all references to the instance are removed.
Arguments:
pRefCnt - pointer to uninitialized Reference Control Block
InstanceHandle - handle to the managed instance.
DeleteHandler - pointer to delete function, NULL is OK.
Return Value:
The function's value is VOID.
--*/
{
ASSERT( pRefCnt );
// Set the reference to 1 and save the instance
// handle and the delete handler.
pRefCnt->Count = 0;
pRefCnt->Instance = InstanceHandle;
pRefCnt->DeleteHandler = DeleteHandler;
#if DBG
pRefCnt->Sig = REF_SIG;
RtlZeroMemory(pRefCnt->Tags, sizeof(REF_TAG) * TAG_CNT);
pRefCnt->Tags[0].Tag = 'LTOT';
CTEInitLock(&pRefCnt->Lock);
#endif
}
#if DBG
VOID
ReferenceAddDbg(PREF_CNT pRefCnt, ULONG Tag)
{
int i;
CTELockHandle hLock;
int TotalPerArray = 0;
ASSERT(pRefCnt->Sig == REF_SIG);
CTEGetLock(&pRefCnt->Lock, &hLock);
for (i = 1; i < TAG_CNT; i++)
{
if (pRefCnt->Tags[i].Tag == 0 || pRefCnt->Tags[i].Tag == Tag)
{
pRefCnt->Tags[i].Tag = Tag;
InterlockedIncrement(&pRefCnt->Tags[i].Count);
break;
}
}
ASSERT(i < TAG_CNT);
InterlockedIncrement(&pRefCnt->Tags[0].Count);
InterlockedIncrement(&pRefCnt->Count);
ASSERT(pRefCnt->Tags[0].Count == pRefCnt->Count);
// sanity check
/*
for (i = 1; i < TAG_CNT; i++)
{
if (pRefCnt->Tags[i].Tag != 0)
{
TotalPerArray += pRefCnt->Tags[i].Count;
continue;
}
}
ASSERT(TotalPerArray == pRefCnt->Tags[0].Count);
if (TotalPerArray != pRefCnt->Tags[0].Count)
{
DbgBreakPoint();
}
*/
CTEFreeLock(&pRefCnt->Lock, hLock);
}
VOID
ReferenceRemoveDbg(PREF_CNT pRefCnt, BOOLEAN LockHeld, ULONG Tag)
{
int i;
CTELockHandle hLock;
int TotalPerArray = 0;
BOOLEAN FoundIt = FALSE;
ASSERT(pRefCnt->Sig == REF_SIG);
CTEGetLock(&pRefCnt->Lock, &hLock);
for (i = 1; i < TAG_CNT; i++)
{
if (pRefCnt->Tags[i].Tag == Tag)
{
FoundIt = TRUE;
ASSERT(pRefCnt->Tags[i].Count > 0);
InterlockedDecrement(&pRefCnt->Tags[i].Count);
if (pRefCnt->Tags[i].Count == 0)
pRefCnt->Tags[i].Tag = Tag;
break;
}
}
ASSERT(FoundIt);
ASSERT(pRefCnt->Tags[0].Count > 0);
ASSERT(pRefCnt->Tags[0].Count == pRefCnt->Count);
InterlockedDecrement(&pRefCnt->Tags[0].Count);
if (InterlockedDecrement(&pRefCnt->Count) > 0 )
{
CTEFreeLock(&pRefCnt->Lock, hLock);
}
else if (pRefCnt->DeleteHandler)
{
CTEFreeLock(&pRefCnt->Lock, hLock);
(pRefCnt->DeleteHandler)( pRefCnt->Instance, LockHeld );
}
else
{
CTEFreeLock(&pRefCnt->Lock, hLock);
}
}
#endif