gecko-dev/db/btree/bt_open.c
1998-10-15 03:56:37 +00:00

349 lines
9.4 KiB
C

/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1996, 1997, 1998
* Sleepycat Software. All rights reserved.
*/
/*
* Copyright (c) 1990, 1993, 1994, 1995, 1996
* Keith Bostic. All rights reserved.
*/
/*
* Copyright (c) 1990, 1993, 1994, 1995
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Mike Olson.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "config.h"
#ifndef lint
static const char sccsid[] = "@(#)bt_open.c 10.27 (Sleepycat) 5/6/98";
#endif /* not lint */
/*
* Implementation of btree access method for 4.4BSD.
*
* The design here was originally based on that of the btree access method
* used in the Postgres database system at UC Berkeley. This implementation
* is wholly independent of the Postgres code.
*/
#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>
#include <errno.h>
#include <limits.h>
#include <string.h>
#endif
#include "db_int.h"
#include "db_page.h"
#include "btree.h"
static int __bam_keyalloc __P((BTREE *));
static int __bam_setmeta __P((DB *, BTREE *));
/*
* __bam_open --
* Open a btree.
*
* PUBLIC: int __bam_open __P((DB *, DBTYPE, DB_INFO *));
*/
int
__bam_open(dbp, type, dbinfo)
DB *dbp;
DBTYPE type;
DB_INFO *dbinfo;
{
BTREE *t;
int ret;
/* Allocate the btree internal structure. */
if ((t = (BTREE *)__db_calloc(1, sizeof(BTREE))) == NULL)
return (ENOMEM);
t->bt_sp = t->bt_csp = t->bt_stack;
t->bt_esp = t->bt_stack + sizeof(t->bt_stack) / sizeof(t->bt_stack[0]);
if ((type == DB_RECNO || F_ISSET(dbp, DB_BT_RECNUM)) &&
(ret = __bam_keyalloc(t)) != 0)
goto err;
/*
* Intention is to make sure all of the user's selections are okay
* here and then use them without checking.
*/
if (dbinfo != NULL) {
/* Minimum number of keys per page. */
if (dbinfo->bt_minkey == 0)
t->bt_minkey = DEFMINKEYPAGE;
else {
if (dbinfo->bt_minkey < 2)
goto einval;
t->bt_minkey = dbinfo->bt_minkey;
}
/* Maximum number of keys per page. */
if (dbinfo->bt_maxkey == 0)
t->bt_maxkey = 0;
else {
if (dbinfo->bt_maxkey < 1)
goto einval;
t->bt_maxkey = dbinfo->bt_maxkey;
}
/*
* If no comparison, use default comparison. If no comparison
* and no prefix, use default prefix. (We can't default the
* prefix if the user supplies a comparison routine; shortening
* the keys may break their comparison algorithm.)
*/
t->bt_compare = dbinfo->bt_compare == NULL ?
__bam_defcmp : dbinfo->bt_compare;
t->bt_prefix = dbinfo->bt_prefix == NULL ?
(dbinfo->bt_compare == NULL ?
__bam_defpfx : NULL) : dbinfo->bt_prefix;
} else {
t->bt_minkey = DEFMINKEYPAGE;
t->bt_compare = __bam_defcmp;
t->bt_prefix = __bam_defpfx;
}
/* Initialize the remaining fields of the DB. */
dbp->type = type;
dbp->internal = t;
dbp->cursor = __bam_cursor;
dbp->del = __bam_delete;
dbp->get = __bam_get;
dbp->put = __bam_put;
dbp->stat = __bam_stat;
dbp->sync = __bam_sync;
/*
* The btree data structure requires that at least two key/data pairs
* can fit on a page, but other than that there's no fixed requirement.
* Translate the minimum number of items into the bytes a key/data pair
* can use before being placed on an overflow page. We calculate for
* the worst possible alignment by assuming every item requires the
* maximum alignment for padding.
*
* Recno uses the btree bt_ovflsize value -- it's close enough.
*/
t->bt_ovflsize = (dbp->pgsize - P_OVERHEAD) / (t->bt_minkey * P_INDX)
- (BKEYDATA_PSIZE(0) + ALIGN(1, 4));
/* Create a root page if new tree. */
if ((ret = __bam_setmeta(dbp, t)) != 0)
goto err;
return (0);
einval: ret = EINVAL;
err: if (t != NULL) {
/* If we allocated room for key/data return, discard it. */
if (t->bt_rkey.data != NULL)
__db_free(t->bt_rkey.data);
FREE(t, sizeof(BTREE));
}
return (ret);
}
/*
* __bam_bdup --
* Create a BTREE handle for a threaded DB handle.
*
* PUBLIC: int __bam_bdup __P((DB *, DB *));
*/
int
__bam_bdup(orig, new)
DB *orig, *new;
{
BTREE *t, *ot;
int ret;
ot = orig->internal;
if ((t = (BTREE *)__db_calloc(1, sizeof(*t))) == NULL)
return (ENOMEM);
/*
* !!!
* Ignore the cursor queue, only the first DB has attached cursors.
*/
t->bt_sp = t->bt_csp = t->bt_stack;
t->bt_esp = t->bt_stack + sizeof(t->bt_stack) / sizeof(t->bt_stack[0]);
if ((orig->type == DB_RECNO || F_ISSET(orig, DB_BT_RECNUM)) &&
(ret = __bam_keyalloc(t)) != 0) {
FREE(t, sizeof(*t));
return (ret);
}
t->bt_maxkey = ot->bt_maxkey;
t->bt_minkey = ot->bt_minkey;
t->bt_compare = ot->bt_compare;
t->bt_prefix = ot->bt_prefix;
t->bt_ovflsize = ot->bt_ovflsize;
/*
* !!!
* The entire RECNO structure is shared. If it breaks, the application
* was misusing it to start with.
*/
t->bt_recno = ot->bt_recno;
new->internal = t;
return (0);
}
/*
* __bam_keyalloc --
* Allocate return memory for recno keys.
*/
static int
__bam_keyalloc(t)
BTREE *t;
{
/*
* Recno keys are always the same size, and we don't want to have
* to check for space on each return. Allocate it now.
*/
if ((t->bt_rkey.data = (void *)__db_malloc(sizeof(db_recno_t))) == NULL)
return (ENOMEM);
t->bt_rkey.ulen = sizeof(db_recno_t);
return (0);
}
/*
* __bam_setmeta --
* Check (and optionally create) a tree.
*/
static int
__bam_setmeta(dbp, t)
DB *dbp;
BTREE *t;
{
BTMETA *meta;
PAGE *root;
DB_LOCK metalock, rootlock;
db_pgno_t pgno;
int ret;
/* Get, and optionally create the metadata page. */
pgno = PGNO_METADATA;
if ((ret =
__bam_lget(dbp, 0, PGNO_METADATA, DB_LOCK_WRITE, &metalock)) != 0)
return (ret);
if ((ret =
__bam_pget(dbp, (PAGE **)&meta, &pgno, DB_MPOOL_CREATE)) != 0) {
(void)__BT_LPUT(dbp, metalock);
return (ret);
}
/*
* If the magic number is correct, we're not creating the tree.
* Correct any fields that may not be right. Note, all of the
* local flags were set by db_open(3).
*/
if (meta->magic != 0) {
t->bt_maxkey = meta->maxkey;
t->bt_minkey = meta->minkey;
(void)memp_fput(dbp->mpf, (PAGE *)meta, 0);
(void)__BT_LPUT(dbp, metalock);
return (0);
}
/* Initialize the tree structure metadata information. */
memset(meta, 0, sizeof(BTMETA));
ZERO_LSN(meta->lsn);
meta->pgno = PGNO_METADATA;
meta->magic = DB_BTREEMAGIC;
meta->version = DB_BTREEVERSION;
meta->pagesize = dbp->pgsize;
meta->maxkey = t->bt_maxkey;
meta->minkey = t->bt_minkey;
meta->free = PGNO_INVALID;
if (dbp->type == DB_RECNO)
F_SET(meta, BTM_RECNO);
if (F_ISSET(dbp, DB_AM_DUP))
F_SET(meta, BTM_DUP);
if (F_ISSET(dbp, DB_RE_FIXEDLEN))
F_SET(meta, BTM_FIXEDLEN);
if (F_ISSET(dbp, DB_BT_RECNUM))
F_SET(meta, BTM_RECNUM);
if (F_ISSET(dbp, DB_RE_RENUMBER))
F_SET(meta, BTM_RENUMBER);
memcpy(meta->uid, dbp->lock.fileid, DB_FILE_ID_LEN);
/* Create and initialize a root page. */
pgno = PGNO_ROOT;
if ((ret =
__bam_lget(dbp, 0, PGNO_ROOT, DB_LOCK_WRITE, &rootlock)) != 0)
return (ret);
if ((ret = __bam_pget(dbp, &root, &pgno, DB_MPOOL_CREATE)) != 0) {
(void)__BT_LPUT(dbp, rootlock);
return (ret);
}
P_INIT(root, dbp->pgsize, PGNO_ROOT, PGNO_INVALID,
PGNO_INVALID, 1, dbp->type == DB_RECNO ? P_LRECNO : P_LBTREE);
ZERO_LSN(root->lsn);
/* Release the metadata and root pages. */
if ((ret = memp_fput(dbp->mpf, (PAGE *)meta, DB_MPOOL_DIRTY)) != 0)
return (ret);
if ((ret = memp_fput(dbp->mpf, root, DB_MPOOL_DIRTY)) != 0)
return (ret);
/*
* Flush the metadata and root pages to disk -- since the user can't
* transaction protect open, the pages have to exist during recovery.
*
* XXX
* It's not useful to return not-yet-flushed here -- convert it to
* an error.
*/
if ((ret = memp_fsync(dbp->mpf)) == DB_INCOMPLETE)
ret = EINVAL;
/* Release the locks. */
(void)__BT_LPUT(dbp, metalock);
(void)__BT_LPUT(dbp, rootlock);
return (ret);
}