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Reimplement the linked list data structure used throughout the backend.

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In the past, we used a 'Lispy' linked list implementation: a "list" was
merely a pointer to the head node of the list. The problem with that
design is that it makes lappend() and length() linear time. This patch
fixes that problem (and others) by maintaining a count of the list
length and a pointer to the tail node along with each head node pointer.
A "list" is now a pointer to a structure containing some meta-data
about the list; the head and tail pointers in that structure refer
to ListCell structures that maintain the actual linked list of nodes.

The function names of the list API have also been changed to, I hope,
be more logically consistent. By default, the old function names are
still available; they will be disabled-by-default once the rest of
the tree has been updated to use the new API names.
This commit is contained in:
Neil Conway
2004-05-26 04:41:50 +00:00
parent 18d0d10563
commit d0b4399d81
125 changed files with 3639 additions and 3038 deletions
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46
src/backend/commands/user.c
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@ -6,7 +6,7 @@
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/backend/commands/user.c,v 1.140 2004/05/06 16:59:16 momjian Exp $
* $PostgreSQL: pgsql/src/backend/commands/user.c,v 1.141 2004/05/26 04:41:12 neilc Exp $
*
*-------------------------------------------------------------------------
*/
@ -491,8 +491,8 @@ CreateUser(CreateUserStmt *stmt)
sysid_exists = false,
havesysid = false;
int max_id;
List *item,
*option;
ListCell *item;
ListCell *option;
char *password = NULL; /* PostgreSQL user password */
bool encrypt_password = Password_encryption; /* encrypt password? */
char encrypted_password[MD5_PASSWD_LEN + 1];
@ -715,7 +715,7 @@ CreateUser(CreateUserStmt *stmt)
ags.name = strVal(lfirst(item)); /* the group name to add
* this in */
ags.action = +1;
ags.listUsers = makeList1(makeInteger(sysid));
ags.listUsers = list_make1(makeInteger(sysid));
AlterGroup(&ags, "CREATE USER");
}
@ -746,7 +746,7 @@ AlterUser(AlterUserStmt *stmt)
TupleDesc pg_shadow_dsc;
HeapTuple tuple,
new_tuple;
List *option;
ListCell *option;
char *password = NULL; /* PostgreSQL user password */
bool encrypt_password = Password_encryption; /* encrypt password? */
char encrypted_password[MD5_PASSWD_LEN + 1];
@ -1017,7 +1017,7 @@ DropUser(DropUserStmt *stmt)
{
Relation pg_shadow_rel;
TupleDesc pg_shadow_dsc;
List *item;
ListCell *item;
if (!superuser())
ereport(ERROR,
@ -1122,7 +1122,7 @@ DropUser(DropUserStmt *stmt)
/* the group name from which to try to drop the user: */
ags.name = pstrdup(NameStr(((Form_pg_group) GETSTRUCT(tmp_tuple))->groname));
ags.action = -1;
ags.listUsers = makeList1(makeInteger(usesysid));
ags.listUsers = list_make1(makeInteger(usesysid));
AlterGroup(&ags, "DROP USER");
}
heap_endscan(scan);
@ -1283,9 +1283,9 @@ CreateGroup(CreateGroupStmt *stmt)
int max_id;
Datum new_record[Natts_pg_group];
char new_record_nulls[Natts_pg_group];
List *item,
*option,
*newlist = NIL;
ListCell *item;
ListCell *option;
List *newlist = NIL;
IdList *grolist;
int sysid = 0;
List *userElts = NIL;
@ -1397,8 +1397,8 @@ CreateGroup(CreateGroupStmt *stmt)
const char *groupuser = strVal(lfirst(item));
int32 userid = get_usesysid(groupuser);
if (!intMember(userid, newlist))
newlist = lappendi(newlist, userid);
if (!list_member_int(newlist, userid))
newlist = lappend_int(newlist, userid);
}
/* build an array to insert */
@ -1454,8 +1454,8 @@ AlterGroup(AlterGroupStmt *stmt, const char *tag)
IdList *oldarray;
Datum datum;
bool null;
List *newlist,
*item;
List *newlist;
ListCell *item;
/*
* Make sure the user can do this.
@ -1525,8 +1525,8 @@ AlterGroup(AlterGroupStmt *stmt, const char *tag)
sysid = 0; /* keep compiler quiet */
}
if (!intMember(sysid, newlist))
newlist = lappendi(newlist, sysid);
if (!list_member_int(newlist, sysid))
newlist = lappend_int(newlist, sysid);
}
/* Do the update */
@ -1565,8 +1565,8 @@ AlterGroup(AlterGroupStmt *stmt, const char *tag)
/* for dropuser we already know the uid */
sysid = intVal(lfirst(item));
}
if (intMember(sysid, newlist))
newlist = lremovei(sysid, newlist);
if (list_member_int(newlist, sysid))
newlist = list_delete_int(newlist, sysid);
else if (!is_dropuser)
ereport(WARNING,
(errcode(ERRCODE_WARNING),
@ -1636,9 +1636,9 @@ UpdateGroupMembership(Relation group_rel, HeapTuple group_tuple,
static IdList *
IdListToArray(List *members)
{
int nmembers = length(members);
int nmembers = list_length(members);
IdList *newarray;
List *item;
ListCell *item;
int i;
newarray = palloc(ARR_OVERHEAD(1) + nmembers * sizeof(int32));
@ -1650,7 +1650,7 @@ IdListToArray(List *members)
ARR_DIMS(newarray)[0] = nmembers; /* axis is this long */
i = 0;
foreach(item, members)
((int *) ARR_DATA_PTR(newarray))[i++] = lfirsti(item);
((int *) ARR_DATA_PTR(newarray))[i++] = lfirst_int(item);
return newarray;
}
@ -1679,8 +1679,8 @@ IdArrayToList(IdList *oldarray)
sysid = ((int32 *) ARR_DATA_PTR(oldarray))[i];
/* filter out any duplicates --- probably a waste of time */
if (!intMember(sysid, newlist))
newlist = lappendi(newlist, sysid);
if (!list_member_int(newlist, sysid))
newlist = lappend_int(newlist, sysid);
}
return newlist;