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Change SearchSysCache coding conventions so that a reference count is

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maintained for each cache entry.  A cache entry will not be freed until
the matching ReleaseSysCache call has been executed.  This eliminates
worries about cache entries getting dropped while still in use.  See
my posting to pg-hackers of even date for more info.
This commit is contained in:
Tom Lane
2000-11-16 22:30:52 +00:00
parent cff23842a4
commit a933ee38bb
95 changed files with 2672 additions and 2314 deletions
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100
src/backend/lib/dllist.c
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@ -2,7 +2,6 @@
*
* dllist.c
* this is a simple doubly linked list implementation
* replaces the old simplelists stuff
* the elements of the lists are void*
*
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
@ -10,7 +9,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/lib/dllist.c,v 1.18 2000/06/08 22:37:05 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/lib/dllist.c,v 1.19 2000/11/16 22:30:23 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -33,25 +32,33 @@ DLNewList(void)
{
Dllist *l;
l = malloc(sizeof(Dllist));
l = (Dllist *) malloc(sizeof(Dllist));
l->dll_head = 0;
l->dll_tail = 0;
return l;
}
/* free up a list and all the nodes in it --- but *not* whatever the nodes
void
DLInitList(Dllist *list)
{
list->dll_head = 0;
list->dll_tail = 0;
}
/*
* free up a list and all the nodes in it --- but *not* whatever the nodes
* might point to!
*/
void
DLFreeList(Dllist *l)
DLFreeList(Dllist *list)
{
Dlelem *curr;
while ((curr = DLRemHead(l)) != 0)
while ((curr = DLRemHead(list)) != 0)
free(curr);
free(l);
free(list);
}
Dlelem *
@ -59,7 +66,7 @@ DLNewElem(void *val)
{
Dlelem *e;
e = malloc(sizeof(Dlelem));
e = (Dlelem *) malloc(sizeof(Dlelem));
e->dle_next = 0;
e->dle_prev = 0;
e->dle_val = val;
@ -67,62 +74,21 @@ DLNewElem(void *val)
return e;
}
void
DLInitElem(Dlelem *e, void *val)
{
e->dle_next = 0;
e->dle_prev = 0;
e->dle_val = val;
e->dle_list = 0;
}
void
DLFreeElem(Dlelem *e)
{
free(e);
}
Dlelem *
DLGetHead(Dllist *l)
{
return l ? l->dll_head : 0;
}
/* get the value stored in the first element */
#ifdef NOT_USED
void *
DLGetHeadVal(Dllist *l)
{
Dlelem *e = DLGetHead(l);
return e ? e->dle_val : 0;
}
#endif
Dlelem *
DLGetTail(Dllist *l)
{
return l ? l->dll_tail : 0;
}
/* get the value stored in the last element */
#ifdef NOT_USED
void *
DLGetTailVal(Dllist *l)
{
Dlelem *e = DLGetTail(l);
return e ? e->dle_val : 0;
}
#endif
#ifdef NOT_USED
Dlelem *
DLGetPred(Dlelem *e) /* get predecessor */
{
return e ? e->dle_prev : 0;
}
#endif
Dlelem *
DLGetSucc(Dlelem *e) /* get successor */
{
return e ? e->dle_next : 0;
}
void
DLRemove(Dlelem *e)
{
@ -131,16 +97,16 @@ DLRemove(Dlelem *e)
if (e->dle_prev)
e->dle_prev->dle_next = e->dle_next;
else
/* must be the head element */
{
/* must be the head element */
Assert(e == l->dll_head);
l->dll_head = e->dle_next;
}
if (e->dle_next)
e->dle_next->dle_prev = e->dle_prev;
else
/* must be the tail element */
{
/* must be the tail element */
Assert(e == l->dll_tail);
l->dll_tail = e->dle_prev;
}
@ -194,12 +160,12 @@ DLRemHead(Dllist *l)
l->dll_head = result->dle_next;
result->dle_next = 0;
result->dle_list = 0;
if (result == l->dll_tail) /* if the head is also the tail */
l->dll_tail = 0;
result->dle_next = 0;
result->dle_list = 0;
return result;
}
@ -217,12 +183,12 @@ DLRemTail(Dllist *l)
l->dll_tail = result->dle_prev;
result->dle_prev = 0;
result->dle_list = 0;
if (result == l->dll_head) /* if the tail is also the head */
l->dll_head = 0;
result->dle_prev = 0;
result->dle_list = 0;
return result;
}
@ -241,8 +207,8 @@ DLMoveToFront(Dlelem *e)
if (e->dle_next)
e->dle_next->dle_prev = e->dle_prev;
else
/* must be the tail element */
{
/* must be the tail element */
Assert(e == l->dll_tail);
l->dll_tail = e->dle_prev;
}