gecko-dev/db/hash/hash.c

1480 строки
38 KiB
C
Исходник Обычный вид История

1998-10-15 07:56:37 +04:00
/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1996, 1997, 1998
* Sleepycat Software. All rights reserved.
*/
/*
* Copyright (c) 1990, 1993, 1994
* Margo Seltzer. All rights reserved.
*/
/*
* Copyright (c) 1990, 1993, 1994
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Margo Seltzer.
*
* 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[] = "@(#)hash.c 10.45 (Sleepycat) 5/11/98";
#endif /* not lint */
#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#endif
#include "db_int.h"
#include "shqueue.h"
#include "db_page.h"
#include "db_am.h"
#include "db_ext.h"
#include "hash.h"
#include "log.h"
static int __ham_c_close __P((DBC *));
static int __ham_c_del __P((DBC *, u_int32_t));
static int __ham_c_get __P((DBC *, DBT *, DBT *, u_int32_t));
static int __ham_c_put __P((DBC *, DBT *, DBT *, u_int32_t));
static int __ham_c_init __P((DB *, DB_TXN *, DBC **));
static int __ham_cursor __P((DB *, DB_TXN *, DBC **));
static int __ham_delete __P((DB *, DB_TXN *, DBT *, u_int32_t));
static int __ham_dup_return __P((HTAB *, HASH_CURSOR *, DBT *, u_int32_t));
static int __ham_get __P((DB *, DB_TXN *, DBT *, DBT *, u_int32_t));
static void __ham_init_htab __P((HTAB *, u_int32_t, u_int32_t));
static int __ham_lookup __P((HTAB *,
HASH_CURSOR *, const DBT *, u_int32_t, db_lockmode_t));
static int __ham_overwrite __P((HTAB *, HASH_CURSOR *, DBT *));
static int __ham_put __P((DB *, DB_TXN *, DBT *, DBT *, u_int32_t));
static int __ham_sync __P((DB *, u_int32_t));
/************************** INTERFACE ROUTINES ***************************/
/* OPEN/CLOSE */
/*
* __ham_open --
*
* PUBLIC: int __ham_open __P((DB *, DB_INFO *));
*/
int
__ham_open(dbp, dbinfo)
DB *dbp;
DB_INFO *dbinfo;
{
DB_ENV *dbenv;
DBC *curs;
HTAB *hashp;
int file_existed, ret;
dbenv = dbp->dbenv;
if ((hashp = (HTAB *)__db_calloc(1, sizeof(HTAB))) == NULL)
return (ENOMEM);
hashp->dbp = dbp;
/* Set the hash function if specified by the user. */
if (dbinfo != NULL && dbinfo->h_hash != NULL)
hashp->hash = dbinfo->h_hash;
/*
* Initialize the remaining fields of the dbp. The type, close and
* fd functions are all set in db_open.
*/
dbp->internal = hashp;
dbp->cursor = __ham_cursor;
dbp->del = __ham_delete;
dbp->get = __ham_get;
dbp->put = __ham_put;
dbp->sync = __ham_sync;
/* If locking is turned on, lock the meta data page. */
if (F_ISSET(dbp, DB_AM_LOCKING)) {
dbp->lock.pgno = BUCKET_INVALID;
if ((ret = lock_get(dbenv->lk_info, dbp->locker,
0, &dbp->lock_dbt, DB_LOCK_READ, &hashp->hlock)) != 0) {
if (ret < 0)
ret = EAGAIN;
goto out;
}
}
/*
* Now, we can try to read the meta-data page and figure out
* if we set up locking and get the meta-data page properly.
* If this is a new file, initialize it, and put it back dirty.
*/
if ((ret = __ham_get_page(hashp->dbp, 0, (PAGE **)&hashp->hdr)) != 0)
goto out;
/* Initialize the hashp structure */
if (hashp->hdr->magic == DB_HASHMAGIC) {
file_existed = 1;
/* File exists, verify the data in the header. */
if (hashp->hash == NULL)
hashp->hash =
hashp->hdr->version < 5 ? __ham_func4 : __ham_func5;
if (hashp->hash(CHARKEY, sizeof(CHARKEY)) !=
hashp->hdr->h_charkey) {
__db_err(hashp->dbp->dbenv,
"hash: incompatible hash function");
ret = EINVAL;
goto out;
}
if (F_ISSET(hashp->hdr, DB_HASH_DUP))
F_SET(dbp, DB_AM_DUP);
} else {
/*
* File does not exist, we must initialize the header. If
* locking is enabled that means getting a write lock first.
*/
file_existed = 0;
if (F_ISSET(dbp, DB_AM_LOCKING) &&
((ret = lock_put(dbenv->lk_info, hashp->hlock)) != 0 ||
(ret = lock_get(dbenv->lk_info, dbp->locker, 0,
&dbp->lock_dbt, DB_LOCK_WRITE, &hashp->hlock)) != 0)) {
if (ret < 0)
ret = EAGAIN;
goto out;
}
__ham_init_htab(hashp,
dbinfo != NULL ? dbinfo->h_nelem : 0,
dbinfo != NULL ? dbinfo->h_ffactor : 0);
if (F_ISSET(dbp, DB_AM_DUP))
F_SET(hashp->hdr, DB_HASH_DUP);
if ((ret = __ham_dirty_page(hashp, (PAGE *)hashp->hdr)) != 0)
goto out;
}
/* Initialize the default cursor. */
__ham_c_init(dbp, NULL, &curs);
TAILQ_INSERT_TAIL(&dbp->curs_queue, curs, links);
/* Allocate memory for our split buffer. */
if ((hashp->split_buf = (PAGE *)__db_malloc(dbp->pgsize)) == NULL) {
ret = ENOMEM;
goto out;
}
#ifdef NO_STATISTICS_FOR_DB_ERR
__db_err(dbp->dbenv,
"%s%lx\n%s%ld\n%s%ld\n%s%ld\n%s%ld\n%s0x%lx\n%s0x%lx\n%s%ld\n%s%ld\n%s0x%lx",
"TABLE POINTER ", (long)hashp,
"BUCKET SIZE ", (long)hashp->hdr->pagesize,
"FILL FACTOR ", (long)hashp->hdr->ffactor,
"MAX BUCKET ", (long)hashp->hdr->max_bucket,
"OVFL POINT ", (long)hashp->hdr->ovfl_point,
"LAST FREED ", (long)hashp->hdr->last_freed,
"HIGH MASK ", (long)hashp->hdr->high_mask,
"LOW MASK ", (long)hashp->hdr->low_mask,
"NELEM ", (long)hashp->hdr->nelem,
"FLAGS ", (long)hashp->hdr->flags);
#endif
/* Release the meta data page */
(void)__ham_put_page(hashp->dbp, (PAGE *)hashp->hdr, 0);
if (F_ISSET(dbp, DB_AM_LOCKING) &&
(ret = lock_put(dbenv->lk_info, hashp->hlock)) != 0) {
if (ret < 0)
ret = EAGAIN;
goto out;
}
hashp->hlock = 0;
hashp->hdr = NULL;
/* Sync the file so that we know that the meta data goes to disk. */
if (!file_existed && (ret = dbp->sync(dbp, 0)) != 0)
goto out;
return (0);
out: (void)__ham_close(dbp);
return (ret);
}
/*
* PUBLIC: int __ham_close __P((DB *));
*/
int
__ham_close(dbp)
DB *dbp;
{
HTAB *hashp;
int ret, t_ret;
DEBUG_LWRITE(dbp, NULL, "ham_close", NULL, NULL, 0);
hashp = (HTAB *)dbp->internal;
ret = 0;
/* Free the split page. */
if (hashp->split_buf)
FREE(hashp->split_buf, dbp->pgsize);
if (hashp->hdr && (t_ret = __ham_put_page(hashp->dbp,
(PAGE *)hashp->hdr, 0)) != 0 && ret == 0)
ret = t_ret;
if (hashp->hlock && (t_ret = lock_put(hashp->dbp->dbenv->lk_info,
hashp->hlock)) != 0 && ret == 0)
ret = t_ret;
FREE(hashp, sizeof(HTAB));
dbp->internal = NULL;
return (ret);
}
/************************** LOCAL CREATION ROUTINES **********************/
/*
* Returns 0 on No Error
*/
static void
__ham_init_htab(hashp, nelem, ffactor)
HTAB *hashp;
u_int32_t nelem, ffactor;
{
int32_t l2, nbuckets;
memset(hashp->hdr, 0, sizeof(HASHHDR));
hashp->hdr->ffactor = ffactor;
hashp->hdr->pagesize = hashp->dbp->pgsize;
ZERO_LSN(hashp->hdr->lsn);
hashp->hdr->magic = DB_HASHMAGIC;
hashp->hdr->version = DB_HASHVERSION;
if (hashp->hash == NULL)
hashp->hash =
hashp->hdr->version < 5 ? __ham_func4 : __ham_func5;
hashp->hdr->h_charkey = hashp->hash(CHARKEY, sizeof(CHARKEY));
if (nelem != 0 && hashp->hdr->ffactor != 0) {
nelem = (nelem - 1) / hashp->hdr->ffactor + 1;
l2 = __db_log2(nelem > 2 ? nelem : 2);
} else
l2 = 2;
nbuckets = 1 << l2;
hashp->hdr->ovfl_point = l2;
hashp->hdr->last_freed = PGNO_INVALID;
hashp->hdr->max_bucket = hashp->hdr->high_mask = nbuckets - 1;
hashp->hdr->low_mask = (nbuckets >> 1) - 1;
memcpy(hashp->hdr->uid, hashp->dbp->lock.fileid, DB_FILE_ID_LEN);
}
/********************** DESTROY/CLOSE ROUTINES ************************/
/*
* Write modified pages to disk
*
* Returns:
* 0 == OK
* -1 ERROR
*/
static int
__ham_sync(dbp, flags)
DB *dbp;
u_int32_t flags;
{
int ret;
DEBUG_LWRITE(dbp, NULL, "ham_sync", NULL, NULL, flags);
if ((ret = __db_syncchk(dbp, flags)) != 0)
return (ret);
if (F_ISSET(dbp, DB_AM_RDONLY))
return (0);
if ((ret = memp_fsync(dbp->mpf)) == DB_INCOMPLETE)
ret = 0;
return (ret);
}
/*******************************SEARCH ROUTINES *****************************/
/*
* All the access routines return
*
* Returns:
* 0 on SUCCESS
* 1 to indicate an external ERROR (i.e. key not found, etc)
* -1 to indicate an internal ERROR (i.e. out of memory, etc)
*/
static int
__ham_get(dbp, txn, key, data, flags)
DB *dbp;
DB_TXN *txn;
DBT *key;
DBT *data;
u_int32_t flags;
{
DB *ldbp;
HTAB *hashp;
HASH_CURSOR *hcp;
int ret, t_ret;
DEBUG_LREAD(dbp, txn, "ham_get", key, NULL, flags);
if ((ret = __db_getchk(dbp, key, data, flags)) != 0)
return (ret);
ldbp = dbp;
if (F_ISSET(dbp, DB_AM_THREAD) &&
(ret = __db_gethandle(dbp, __ham_hdup, &ldbp)) != 0)
return (ret);
hashp = (HTAB *)ldbp->internal;
SET_LOCKER(ldbp, txn);
GET_META(ldbp, hashp);
hashp->hash_accesses++;
hcp = (HASH_CURSOR *)TAILQ_FIRST(&ldbp->curs_queue)->internal;
if ((ret = __ham_lookup(hashp, hcp, key, 0, DB_LOCK_READ)) == 0)
if (F_ISSET(hcp, H_OK))
ret = __ham_dup_return(hashp, hcp, data, DB_FIRST);
else /* Key was not found */
ret = DB_NOTFOUND;
if ((t_ret = __ham_item_done(hashp, hcp, 0)) != 0 && ret == 0)
ret = t_ret;
RELEASE_META(ldbp, hashp);
if (F_ISSET(dbp, DB_AM_THREAD))
__db_puthandle(ldbp);
return (ret);
}
static int
__ham_put(dbp, txn, key, data, flags)
DB *dbp;
DB_TXN *txn;
DBT *key;
DBT *data;
u_int32_t flags;
{
DB *ldbp;
DBT tmp_val, *myval;
HASH_CURSOR *hcp;
HTAB *hashp;
u_int32_t nbytes;
int ret, t_ret;
DEBUG_LWRITE(dbp, txn, "ham_put", key, data, flags);
if ((ret = __db_putchk(dbp, key, data,
flags, F_ISSET(dbp, DB_AM_RDONLY), F_ISSET(dbp, DB_AM_DUP))) != 0)
return (ret);
ldbp = dbp;
if (F_ISSET(dbp, DB_AM_THREAD) &&
(ret = __db_gethandle(dbp, __ham_hdup, &ldbp)) != 0)
return (ret);
hashp = (HTAB *)ldbp->internal;
SET_LOCKER(ldbp, txn);
GET_META(ldbp, hashp);
hcp = TAILQ_FIRST(&ldbp->curs_queue)->internal;
nbytes = (ISBIG(hashp, key->size) ? HOFFPAGE_PSIZE :
HKEYDATA_PSIZE(key->size)) +
(ISBIG(hashp, data->size) ? HOFFPAGE_PSIZE :
HKEYDATA_PSIZE(data->size));
hashp->hash_accesses++;
ret = __ham_lookup(hashp, hcp, key, nbytes, DB_LOCK_WRITE);
if (ret == DB_NOTFOUND) {
ret = 0;
if (hcp->seek_found_page != PGNO_INVALID &&
hcp->seek_found_page != hcp->pgno) {
if ((ret = __ham_item_done(hashp, hcp, 0)) != 0)
goto out;
hcp->pgno = hcp->seek_found_page;
hcp->bndx = NDX_INVALID;
}
if (F_ISSET(data, DB_DBT_PARTIAL) && data->doff != 0) {
/*
* Doing a partial put, but the key does not exist
* and we are not beginning the write at 0. We
* must create a data item padded up to doff and
* then write the new bytes represented by val.
*/
ret = __ham_init_dbt(&tmp_val, data->size + data->doff,
&hcp->big_data, &hcp->big_datalen);
if (ret == 0) {
memset(tmp_val.data, 0, data->doff);
memcpy((u_int8_t *)tmp_val.data + data->doff,
data->data, data->size);
myval = &tmp_val;
}
} else
myval = (DBT *)data;
if (ret == 0)
ret = __ham_add_el(hashp, hcp, key, myval, H_KEYDATA);
} else if (ret == 0 && F_ISSET(hcp, H_OK)) {
if (flags == DB_NOOVERWRITE)
ret = DB_KEYEXIST;
else if (F_ISSET(ldbp, DB_AM_DUP))
ret = __ham_add_dup(hashp, hcp, data, DB_KEYLAST);
else
ret = __ham_overwrite(hashp, hcp, data);
}
/* Free up all the cursor pages. */
if ((t_ret = __ham_item_done(hashp, hcp, ret == 0)) != 0 && ret == 0)
ret = t_ret;
/* Now check if we have to grow. */
out: if (ret == 0 && F_ISSET(hcp, H_EXPAND)) {
ret = __ham_expand_table(hashp);
F_CLR(hcp, H_EXPAND);
}
if ((t_ret = __ham_item_done(hashp, hcp, ret == 0)) != 0 && ret == 0)
ret = t_ret;
RELEASE_META(ldbp, hashp);
if (F_ISSET(dbp, DB_AM_THREAD))
__db_puthandle(ldbp);
return (ret);
}
static int
__ham_cursor(dbp, txnid, dbcp)
DB *dbp;
DB_TXN *txnid;
DBC **dbcp;
{
int ret;
DEBUG_LWRITE(dbp, txnid, "ham_cursor", NULL, NULL, 0);
if ((ret = __ham_c_init(dbp, txnid, dbcp)) != 0)
return (ret);
DB_THREAD_LOCK(dbp);
TAILQ_INSERT_TAIL(&dbp->curs_queue, *dbcp, links);
DB_THREAD_UNLOCK(dbp);
return (ret);
}
static int
__ham_c_init(dbp, txnid, dbcp)
DB *dbp;
DB_TXN *txnid;
DBC **dbcp;
{
DBC *db_curs;
HASH_CURSOR *new_curs;
if ((db_curs = (DBC *)__db_calloc(sizeof(DBC), 1)) == NULL)
return (ENOMEM);
if ((new_curs =
(HASH_CURSOR *)__db_calloc(sizeof(struct cursor_t), 1)) == NULL) {
FREE(db_curs, sizeof(DBC));
return (ENOMEM);
}
db_curs->internal = new_curs;
db_curs->c_close = __ham_c_close;
db_curs->c_del = __ham_c_del;
db_curs->c_get = __ham_c_get;
db_curs->c_put = __ham_c_put;
db_curs->txn = txnid;
db_curs->dbp = dbp;
new_curs->db_cursor = db_curs;
__ham_item_init(new_curs);
if (dbcp != NULL)
*dbcp = db_curs;
return (0);
}
static int
__ham_delete(dbp, txn, key, flags)
DB *dbp;
DB_TXN *txn;
DBT *key;
u_int32_t flags;
{
DB *ldbp;
HTAB *hashp;
HASH_CURSOR *hcp;
int ret, t_ret;
DEBUG_LWRITE(dbp, txn, "ham_delete", key, NULL, flags);
if ((ret =
__db_delchk(dbp, key, flags, F_ISSET(dbp, DB_AM_RDONLY))) != 0)
return (ret);
ldbp = dbp;
if (F_ISSET(dbp, DB_AM_THREAD) &&
(ret = __db_gethandle(dbp, __ham_hdup, &ldbp)) != 0)
return (ret);
hashp = (HTAB *)ldbp->internal;
SET_LOCKER(ldbp, txn);
GET_META(ldbp, hashp);
hcp = TAILQ_FIRST(&ldbp->curs_queue)->internal;
hashp->hash_accesses++;
if ((ret = __ham_lookup(hashp, hcp, key, 0, DB_LOCK_WRITE)) == 0)
if (F_ISSET(hcp, H_OK))
ret = __ham_del_pair(hashp, hcp, 1);
else
ret = DB_NOTFOUND;
if ((t_ret = __ham_item_done(hashp, hcp, ret == 0)) != 0 && ret == 0)
ret = t_ret;
RELEASE_META(ldbp, hashp);
if (F_ISSET(dbp, DB_AM_THREAD))
__db_puthandle(ldbp);
return (ret);
}
/* ****************** CURSORS ********************************** */
static int
__ham_c_close(cursor)
DBC *cursor;
{
DB *ldbp;
int ret;
DEBUG_LWRITE(cursor->dbp, cursor->txn, "ham_c_close", NULL, NULL, 0);
/*
* If the pagep, dpagep, and lock fields of the cursor are all NULL,
* then there really isn't a need to get a handle here. However,
* the normal case is that at least one of those fields is non-NULL,
* and putting those checks in here would couple the ham_item_done
* functionality with cursor close which would be pretty disgusting.
* Instead, we pay the overhead here of always getting the handle.
*/
ldbp = cursor->dbp;
if (F_ISSET(cursor->dbp, DB_AM_THREAD) &&
(ret = __db_gethandle(cursor->dbp, __ham_hdup, &ldbp)) != 0)
return (ret);
ret = __ham_c_iclose(ldbp, cursor);
if (F_ISSET(ldbp, DB_AM_THREAD))
__db_puthandle(ldbp);
return (ret);
}
/*
* __ham_c_iclose --
*
* Internal cursor close routine; assumes it is being passed the correct
* handle, rather than getting and putting a handle.
*
* PUBLIC: int __ham_c_iclose __P((DB *, DBC *));
*/
int
__ham_c_iclose(dbp, dbc)
DB *dbp;
DBC *dbc;
{
HASH_CURSOR *hcp;
HTAB *hashp;
int ret;
hashp = (HTAB *)dbp->internal;
hcp = (HASH_CURSOR *)dbc->internal;
ret = __ham_item_done(hashp, hcp, 0);
if (hcp->big_key)
FREE(hcp->big_key, hcp->big_keylen);
if (hcp->big_data)
FREE(hcp->big_data, hcp->big_datalen);
/*
* All cursors (except the default ones) are linked off the master.
* Therefore, when we close the cursor, we have to remove it from
* the master, not the local one.
* XXX I am always removing from the master; what about local cursors?
*/
DB_THREAD_LOCK(dbc->dbp);
TAILQ_REMOVE(&dbc->dbp->curs_queue, dbc, links);
DB_THREAD_UNLOCK(dbc->dbp);
FREE(hcp, sizeof(HASH_CURSOR));
FREE(dbc, sizeof(DBC));
return (ret);
}
static int
__ham_c_del(cursor, flags)
DBC *cursor;
u_int32_t flags;
{
DB *ldbp;
HASH_CURSOR *hcp;
HASH_CURSOR save_curs;
HTAB *hashp;
db_pgno_t ppgno, chg_pgno;
int ret, t_ret;
DEBUG_LWRITE(cursor->dbp, cursor->txn, "ham_c_del", NULL, NULL, flags);
ldbp = cursor->dbp;
if (F_ISSET(cursor->dbp, DB_AM_THREAD) &&
(ret = __db_gethandle(cursor->dbp, __ham_hdup, &ldbp)) != 0)
return (ret);
hashp = (HTAB *)ldbp->internal;
hcp = (HASH_CURSOR *)cursor->internal;
save_curs = *hcp;
if ((ret = __db_cdelchk(ldbp, flags,
F_ISSET(ldbp, DB_AM_RDONLY), IS_VALID(hcp))) != 0)
return (ret);
if (F_ISSET(hcp, H_DELETED))
return (DB_NOTFOUND);
SET_LOCKER(hashp->dbp, cursor->txn);
GET_META(hashp->dbp, hashp);
hashp->hash_accesses++;
if ((ret = __ham_get_cpage(hashp, hcp, DB_LOCK_WRITE)) != 0)
goto out;
if (F_ISSET(hcp, H_ISDUP) && hcp->dpgno != PGNO_INVALID) {
/*
* We are about to remove a duplicate from offpage.
*
* There are 4 cases.
* 1. We will remove an item on a page, but there are more
* items on that page.
* 2. We will remove the last item on a page, but there is a
* following page of duplicates.
* 3. We will remove the last item on a page, this page was the
* last page in a duplicate set, but there were dups before
* it.
* 4. We will remove the last item on a page, removing the last
* duplicate.
* In case 1 hcp->dpagep is unchanged.
* In case 2 hcp->dpagep comes back pointing to the next dup
* page.
* In case 3 hcp->dpagep comes back NULL.
* In case 4 hcp->dpagep comes back NULL.
*
* Case 4 results in deleting the pair off the master page.
* The normal code for doing this knows how to delete the
* duplicates, so we will handle this case in the normal code.
*/
ppgno = PREV_PGNO(hcp->dpagep);
if (ppgno == PGNO_INVALID &&
NEXT_PGNO(hcp->dpagep) == PGNO_INVALID &&
NUM_ENT(hcp->dpagep) == 1)
goto normal;
/* Remove item from duplicate page. */
chg_pgno = hcp->dpgno;
if ((ret = __db_drem(hashp->dbp,
&hcp->dpagep, hcp->dndx, __ham_del_page)) != 0)
goto out;
if (hcp->dpagep == NULL) {
if (ppgno != PGNO_INVALID) { /* Case 3 */
hcp->dpgno = ppgno;
if ((ret = __ham_get_cpage(hashp, hcp,
DB_LOCK_READ)) != 0)
goto out;
hcp->dndx = NUM_ENT(hcp->dpagep);
F_SET(hcp, H_DELETED);
} else { /* Case 4 */
ret = __ham_del_pair(hashp, hcp, 1);
hcp->dpgno = PGNO_INVALID;
/*
* Delpair updated the cursor queue, so we
* don't have to do that here.
*/
chg_pgno = PGNO_INVALID;
}
} else if (PGNO(hcp->dpagep) != hcp->dpgno) {
hcp->dndx = 0; /* Case 2 */
hcp->dpgno = PGNO(hcp->dpagep);
if (ppgno == PGNO_INVALID)
memcpy(HOFFDUP_PGNO(P_ENTRY(hcp->pagep,
H_DATAINDEX(hcp->bndx))),
&hcp->dpgno, sizeof(db_pgno_t));
F_SET(hcp, H_DELETED);
} else /* Case 1 */
F_SET(hcp, H_DELETED);
if (chg_pgno != PGNO_INVALID)
__ham_c_update(hcp, chg_pgno, 0, 0, 1);
} else if (F_ISSET(hcp, H_ISDUP)) { /* on page */
if (hcp->dup_off == 0 && DUP_SIZE(hcp->dup_len) ==
LEN_HDATA(hcp->pagep, hashp->hdr->pagesize, hcp->bndx))
ret = __ham_del_pair(hashp, hcp, 1);
else {
DBT repldbt;
repldbt.flags = 0;
F_SET(&repldbt, DB_DBT_PARTIAL);
repldbt.doff = hcp->dup_off;
repldbt.dlen = DUP_SIZE(hcp->dup_len);
repldbt.size = 0;
ret = __ham_replpair(hashp, hcp, &repldbt, 0);
hcp->dup_tlen -= DUP_SIZE(hcp->dup_len);
F_SET(hcp, H_DELETED);
__ham_c_update(hcp, hcp->pgno,
DUP_SIZE(hcp->dup_len), 0, 1);
}
} else
/* Not a duplicate */
normal: ret = __ham_del_pair(hashp, hcp, 1);
out: if ((t_ret = __ham_item_done(hashp, hcp, ret == 0)) != 0 && ret == 0)
ret = t_ret;
if (ret != 0)
*hcp = save_curs;
RELEASE_META(hashp->dbp, hashp);
if (F_ISSET(cursor->dbp, DB_AM_THREAD))
__db_puthandle(ldbp);
return (ret);
}
static int
__ham_c_get(cursor, key, data, flags)
DBC *cursor;
DBT *key;
DBT *data;
u_int32_t flags;
{
DB *ldbp;
HTAB *hashp;
HASH_CURSOR *hcp, save_curs;
int get_key, ret, t_ret;
DEBUG_LREAD(cursor->dbp, cursor->txn, "ham_c_get",
flags == DB_SET || flags == DB_SET_RANGE ? key : NULL,
NULL, flags);
ldbp = cursor->dbp;
if (F_ISSET(cursor->dbp, DB_AM_THREAD) &&
(ret = __db_gethandle(cursor->dbp, __ham_hdup, &ldbp)) != 0)
return (ret);
hashp = (HTAB *)(ldbp->internal);
hcp = (HASH_CURSOR *)cursor->internal;
save_curs = *hcp;
if ((ret =
__db_cgetchk(hashp->dbp, key, data, flags, IS_VALID(hcp))) != 0)
return (ret);
SET_LOCKER(hashp->dbp, cursor->txn);
GET_META(hashp->dbp, hashp);
hashp->hash_accesses++;
hcp->seek_size = 0;
ret = 0;
get_key = 1;
switch (flags) {
case DB_PREV:
if (hcp->bucket != BUCKET_INVALID) {
ret = __ham_item_prev(hashp, hcp, DB_LOCK_READ);
break;
}
/* FALLTHROUGH */
case DB_LAST:
ret = __ham_item_last(hashp, hcp, DB_LOCK_READ);
break;
case DB_FIRST:
ret = __ham_item_first(hashp, hcp, DB_LOCK_READ);
break;
case DB_NEXT:
if (hcp->bucket == BUCKET_INVALID)
hcp->bucket = 0;
ret = __ham_item_next(hashp, hcp, DB_LOCK_READ);
break;
case DB_SET:
case DB_SET_RANGE:
ret = __ham_lookup(hashp, hcp, key, 0, DB_LOCK_READ);
get_key = 0;
break;
case DB_CURRENT:
if (F_ISSET(hcp, H_DELETED)) {
ret = DB_KEYEMPTY;
goto out;
}
ret = __ham_item(hashp, hcp, DB_LOCK_READ);
break;
}
/*
* Must always enter this loop to do error handling and
* check for big key/data pair.
*/
while (1) {
if (ret != 0 && ret != DB_NOTFOUND)
goto out1;
else if (F_ISSET(hcp, H_OK)) {
/* Get the key. */
if (get_key && (ret = __db_ret(hashp->dbp, hcp->pagep,
H_KEYINDEX(hcp->bndx), key, &hcp->big_key,
&hcp->big_keylen)) != 0)
goto out1;
ret = __ham_dup_return(hashp, hcp, data, flags);
break;
} else if (!F_ISSET(hcp, H_NOMORE)) {
abort();
break;
}
/*
* Ran out of entries in a bucket; change buckets.
*/
switch (flags) {
case DB_LAST:
case DB_PREV:
ret = __ham_item_done(hashp, hcp, 0);
if (hcp->bucket == 0) {
ret = DB_NOTFOUND;
goto out1;
}
hcp->bucket--;
hcp->bndx = NDX_INVALID;
if (ret == 0)
ret = __ham_item_prev(hashp,
hcp, DB_LOCK_READ);
break;
case DB_FIRST:
case DB_NEXT:
ret = __ham_item_done(hashp, hcp, 0);
hcp->bndx = NDX_INVALID;
hcp->bucket++;
hcp->pgno = PGNO_INVALID;
hcp->pagep = NULL;
if (hcp->bucket > hashp->hdr->max_bucket) {
ret = DB_NOTFOUND;
goto out1;
}
if (ret == 0)
ret = __ham_item_next(hashp,
hcp, DB_LOCK_READ);
break;
case DB_SET:
case DB_SET_RANGE:
/* Key not found. */
ret = DB_NOTFOUND;
goto out1;
}
}
out1: if ((t_ret = __ham_item_done(hashp, hcp, 0)) != 0 && ret == 0)
ret = t_ret;
out: if (ret)
*hcp = save_curs;
RELEASE_META(hashp->dbp, hashp);
if (F_ISSET(cursor->dbp, DB_AM_THREAD))
__db_puthandle(ldbp);
return (ret);
}
static int
__ham_c_put(cursor, key, data, flags)
DBC *cursor;
DBT *key;
DBT *data;
u_int32_t flags;
{
DB *ldbp;
HASH_CURSOR *hcp, save_curs;
HTAB *hashp;
u_int32_t nbytes;
int ret, t_ret;
DEBUG_LWRITE(cursor->dbp, cursor->txn, "ham_c_put",
flags == DB_KEYFIRST || flags == DB_KEYLAST ? key : NULL,
data, flags);
ldbp = cursor->dbp;
if (F_ISSET(cursor->dbp, DB_AM_THREAD) &&
(ret = __db_gethandle(cursor->dbp, __ham_hdup, &ldbp)) != 0)
return (ret);
hashp = (HTAB *)(ldbp->internal);
hcp = (HASH_CURSOR *)cursor->internal;
save_curs = *hcp;
if ((ret = __db_cputchk(hashp->dbp, key, data, flags,
F_ISSET(ldbp, DB_AM_RDONLY), IS_VALID(hcp))) != 0)
return (ret);
if (F_ISSET(hcp, H_DELETED))
return (DB_NOTFOUND);
SET_LOCKER(hashp->dbp, cursor->txn);
GET_META(hashp->dbp, hashp);
ret = 0;
switch (flags) {
case DB_KEYLAST:
case DB_KEYFIRST:
nbytes = (ISBIG(hashp, key->size) ? HOFFPAGE_PSIZE :
HKEYDATA_PSIZE(key->size)) +
(ISBIG(hashp, data->size) ? HOFFPAGE_PSIZE :
HKEYDATA_PSIZE(data->size));
ret = __ham_lookup(hashp, hcp, key, nbytes, DB_LOCK_WRITE);
break;
case DB_BEFORE:
case DB_AFTER:
case DB_CURRENT:
ret = __ham_item(hashp, hcp, DB_LOCK_WRITE);
break;
}
if (ret == 0) {
if (flags == DB_CURRENT && !F_ISSET(ldbp, DB_AM_DUP))
ret = __ham_overwrite(hashp, hcp, data);
else
ret = __ham_add_dup(hashp, hcp, data, flags);
}
if (ret == 0 && F_ISSET(hcp, H_EXPAND)) {
ret = __ham_expand_table(hashp);
F_CLR(hcp, H_EXPAND);
}
if ((t_ret = __ham_item_done(hashp, hcp, ret == 0)) != 0 && ret == 0)
ret = t_ret;
if (ret != 0)
*hcp = save_curs;
RELEASE_META(hashp->dbp, hashp);
if (F_ISSET(cursor->dbp, DB_AM_THREAD))
__db_puthandle(ldbp);
return (ret);
}
/********************************* UTILITIES ************************/
/*
* __ham_expand_table --
*
* PUBLIC: int __ham_expand_table __P((HTAB *));
*/
int
__ham_expand_table(hashp)
HTAB *hashp;
{
DB_LSN new_lsn;
u_int32_t old_bucket, new_bucket, spare_ndx;
int ret;
ret = 0;
DIRTY_META(hashp, ret);
if (ret)
return (ret);
/*
* If the split point is about to increase, make sure that we
* have enough extra pages. The calculation here is weird.
* We'd like to do this after we've upped max_bucket, but it's
* too late then because we've logged the meta-data split. What
* we'll do between then and now is increment max bucket and then
* see what the log of one greater than that is; here we have to
* look at the log of max + 2. VERY NASTY STUFF.
*/
if (__db_log2(hashp->hdr->max_bucket + 2) > hashp->hdr->ovfl_point) {
/*
* We are about to shift the split point. Make sure that
* if the next doubling is going to be big (more than 8
* pages), we have some extra pages around.
*/
if (hashp->hdr->max_bucket + 1 >= 8 &&
hashp->hdr->spares[hashp->hdr->ovfl_point] <
hashp->hdr->spares[hashp->hdr->ovfl_point - 1] +
hashp->hdr->ovfl_point + 1)
__ham_init_ovflpages(hashp);
}
/* Now we can log the meta-data split. */
if (DB_LOGGING(hashp->dbp)) {
if ((ret = __ham_splitmeta_log(hashp->dbp->dbenv->lg_info,
(DB_TXN *)hashp->dbp->txn, &new_lsn, 0,
hashp->dbp->log_fileid,
hashp->hdr->max_bucket, hashp->hdr->ovfl_point,
hashp->hdr->spares[hashp->hdr->ovfl_point],
&hashp->hdr->lsn)) != 0)
return (ret);
hashp->hdr->lsn = new_lsn;
}
hashp->hash_expansions++;
new_bucket = ++hashp->hdr->max_bucket;
old_bucket = (hashp->hdr->max_bucket & hashp->hdr->low_mask);
/*
* If the split point is increasing, copy the current contents
* of the spare split bucket to the next bucket.
*/
spare_ndx = __db_log2(hashp->hdr->max_bucket + 1);
if (spare_ndx > hashp->hdr->ovfl_point) {
hashp->hdr->spares[spare_ndx] =
hashp->hdr->spares[hashp->hdr->ovfl_point];
hashp->hdr->ovfl_point = spare_ndx;
}
if (new_bucket > hashp->hdr->high_mask) {
/* Starting a new doubling */
hashp->hdr->low_mask = hashp->hdr->high_mask;
hashp->hdr->high_mask = new_bucket | hashp->hdr->low_mask;
}
if (BUCKET_TO_PAGE(hashp, new_bucket) > MAX_PAGES(hashp)) {
__db_err(hashp->dbp->dbenv,
"hash: Cannot allocate new bucket. Pages exhausted.");
return (ENOSPC);
}
/* Relocate records to the new bucket */
return (__ham_split_page(hashp, old_bucket, new_bucket));
}
/*
* PUBLIC: u_int32_t __ham_call_hash __P((HTAB *, u_int8_t *, int32_t));
*/
u_int32_t
__ham_call_hash(hashp, k, len)
HTAB *hashp;
u_int8_t *k;
int32_t len;
{
u_int32_t n, bucket;
n = (u_int32_t)hashp->hash(k, len);
bucket = n & hashp->hdr->high_mask;
if (bucket > hashp->hdr->max_bucket)
bucket = bucket & hashp->hdr->low_mask;
return (bucket);
}
/*
* Check for duplicates, and call __db_ret appropriately. Release
* everything held by the cursor.
*/
static int
__ham_dup_return(hashp, hcp, val, flags)
HTAB *hashp;
HASH_CURSOR *hcp;
DBT *val;
u_int32_t flags;
{
PAGE *pp;
DBT *myval, tmp_val;
db_indx_t ndx;
db_pgno_t pgno;
u_int8_t *hk, type;
int ret;
db_indx_t len;
/* Check for duplicate and return the first one. */
ndx = H_DATAINDEX(hcp->bndx);
type = HPAGE_TYPE(hcp->pagep, ndx);
pp = hcp->pagep;
myval = val;
/*
* There are 3 cases:
* 1. We are not in duplicate, simply call db_ret.
* 2. We are looking at keys and stumbled onto a duplicate.
* 3. We are in the middle of a duplicate set. (ISDUP set)
*/
/*
* Here we check for the case where we just stumbled onto a
* duplicate. In this case, we do initialization and then
* let the normal duplicate code handle it.
*/
if (!F_ISSET(hcp, H_ISDUP))
if (type == H_DUPLICATE) {
F_SET(hcp, H_ISDUP);
hcp->dup_tlen = LEN_HDATA(hcp->pagep,
hashp->hdr->pagesize, hcp->bndx);
hk = H_PAIRDATA(hcp->pagep, hcp->bndx);
if (flags == DB_LAST || flags == DB_PREV) {
hcp->dndx = 0;
hcp->dup_off = 0;
do {
memcpy(&len,
HKEYDATA_DATA(hk) + hcp->dup_off,
sizeof(db_indx_t));
hcp->dup_off += DUP_SIZE(len);
hcp->dndx++;
} while (hcp->dup_off < hcp->dup_tlen);
hcp->dup_off -= DUP_SIZE(len);
hcp->dndx--;
} else {
memcpy(&len,
HKEYDATA_DATA(hk), sizeof(db_indx_t));
hcp->dup_off = 0;
hcp->dndx = 0;
}
hcp->dup_len = len;
} else if (type == H_OFFDUP) {
F_SET(hcp, H_ISDUP);
memcpy(&pgno, HOFFDUP_PGNO(P_ENTRY(hcp->pagep, ndx)),
sizeof(db_pgno_t));
if (flags == DB_LAST || flags == DB_PREV) {
if ((ret = __db_dend(hashp->dbp,
pgno, &hcp->dpagep)) != 0)
return (ret);
hcp->dpgno = PGNO(hcp->dpagep);
hcp->dndx = NUM_ENT(hcp->dpagep) - 1;
} else if ((ret = __ham_next_cpage(hashp,
hcp, pgno, 0, H_ISDUP)) != 0)
return (ret);
}
/*
* Now, everything is initialized, grab a duplicate if
* necessary.
*/
if (F_ISSET(hcp, H_ISDUP))
if (hcp->dpgno != PGNO_INVALID) {
pp = hcp->dpagep;
ndx = hcp->dndx;
} else {
/*
* Copy the DBT in case we are retrieving into
* user memory and we need the parameters for
* it.
*/
memcpy(&tmp_val, val, sizeof(*val));
F_SET(&tmp_val, DB_DBT_PARTIAL);
tmp_val.dlen = hcp->dup_len;
tmp_val.doff = hcp->dup_off + sizeof(db_indx_t);
myval = &tmp_val;
}
/*
* Finally, if we had a duplicate, pp, ndx, and myval should be
* set appropriately.
*/
if ((ret = __db_ret(hashp->dbp, pp, ndx, myval, &hcp->big_data,
&hcp->big_datalen)) != 0)
return (ret);
/*
* In case we sent a temporary off to db_ret, set the real
* return values.
*/
val->data = myval->data;
val->size = myval->size;
return (0);
}
static int
__ham_overwrite(hashp, hcp, nval)
HTAB *hashp;
HASH_CURSOR *hcp;
DBT *nval;
{
DBT *myval, tmp_val;
u_int8_t *hk;
if (F_ISSET(hashp->dbp, DB_AM_DUP))
return (__ham_add_dup(hashp, hcp, nval, DB_KEYLAST));
else if (!F_ISSET(nval, DB_DBT_PARTIAL)) {
/* Put/overwrite */
memcpy(&tmp_val, nval, sizeof(*nval));
F_SET(&tmp_val, DB_DBT_PARTIAL);
tmp_val.doff = 0;
hk = H_PAIRDATA(hcp->pagep, hcp->bndx);
if (HPAGE_PTYPE(hk) == H_OFFPAGE)
memcpy(&tmp_val.dlen,
HOFFPAGE_TLEN(hk), sizeof(u_int32_t));
else
tmp_val.dlen = LEN_HDATA(hcp->pagep,
hashp->hdr->pagesize,hcp->bndx);
myval = &tmp_val;
} else /* Regular partial put */
myval = nval;
return (__ham_replpair(hashp, hcp, myval, 0));
}
/*
* Given a key and a cursor, sets the cursor to the page/ndx on which
* the key resides. If the key is found, the cursor H_OK flag is set
* and the pagep, bndx, pgno (dpagep, dndx, dpgno) fields are set.
* If the key is not found, the H_OK flag is not set. If the sought
* field is non-0, the pagep, bndx, pgno (dpagep, dndx, dpgno) fields
* are set indicating where an add might take place. If it is 0,
* non of the cursor pointer field are valid.
*/
static int
__ham_lookup(hashp, hcp, key, sought, mode)
HTAB *hashp;
HASH_CURSOR *hcp;
const DBT *key;
u_int32_t sought;
db_lockmode_t mode;
{
db_pgno_t pgno;
u_int32_t tlen;
int match, ret, t_ret;
u_int8_t *hk;
/*
* Set up cursor so that we're looking for space to add an item
* as we cycle through the pages looking for the key.
*/
if ((ret = __ham_item_reset(hashp, hcp)) != 0)
return (ret);
hcp->seek_size = sought;
hcp->bucket = __ham_call_hash(hashp, (u_int8_t *)key->data, key->size);
while (1) {
if ((ret = __ham_item_next(hashp, hcp, mode)) != 0)
return (ret);
if (F_ISSET(hcp, H_NOMORE))
break;
hk = H_PAIRKEY(hcp->pagep, hcp->bndx);
switch (HPAGE_PTYPE(hk)) {
case H_OFFPAGE:
memcpy(&tlen, HOFFPAGE_TLEN(hk), sizeof(u_int32_t));
if (tlen == key->size) {
memcpy(&pgno,
HOFFPAGE_PGNO(hk), sizeof(db_pgno_t));
match = __db_moff(hashp->dbp, key, pgno);
if (match == 0) {
F_SET(hcp, H_OK);
return (0);
}
}
break;
case H_KEYDATA:
if (key->size == LEN_HKEY(hcp->pagep,
hashp->hdr->pagesize, hcp->bndx) &&
memcmp(key->data,
HKEYDATA_DATA(hk), key->size) == 0) {
F_SET(hcp, H_OK);
return (0);
}
break;
case H_DUPLICATE:
case H_OFFDUP:
/*
* These are errors because keys are never
* duplicated, only data items are.
*/
return (__db_pgfmt(hashp->dbp, PGNO(hcp->pagep)));
}
hashp->hash_collisions++;
}
/*
* Item was not found, adjust cursor properly.
*/
if (sought != 0)
return (ret);
if ((t_ret = __ham_item_done(hashp, hcp, 0)) != 0 && ret == 0)
ret = t_ret;
return (ret);
}
/*
* Initialize a dbt using some possibly already allocated storage
* for items.
* PUBLIC: int __ham_init_dbt __P((DBT *, u_int32_t, void **, u_int32_t *));
*/
int
__ham_init_dbt(dbt, size, bufp, sizep)
DBT *dbt;
u_int32_t size;
void **bufp;
u_int32_t *sizep;
{
memset(dbt, 0, sizeof(*dbt));
if (*sizep < size) {
if ((*bufp = (void *)(*bufp == NULL ?
__db_malloc(size) : __db_realloc(*bufp, size))) == NULL) {
*sizep = 0;
return (ENOMEM);
}
*sizep = size;
}
dbt->data = *bufp;
dbt->size = size;
return (0);
}
/*
* Adjust the cursor after an insert or delete. The cursor passed is
* the one that was operated upon; we just need to check any of the
* others.
*
* len indicates the length of the item added/deleted
* add indicates if the item indicated by the cursor has just been
* added (add == 1) or deleted (add == 0).
* dup indicates if the addition occurred into a duplicate set.
*
* PUBLIC: void __ham_c_update
* PUBLIC: __P((HASH_CURSOR *, db_pgno_t, u_int32_t, int, int));
*/
void
__ham_c_update(hcp, chg_pgno, len, add, is_dup)
HASH_CURSOR *hcp;
db_pgno_t chg_pgno;
u_int32_t len;
int add, is_dup;
{
DBC *cp;
HTAB *hp;
HASH_CURSOR *lcp;
int page_deleted;
/*
* Regular adds are always at the end of a given page, so we never
* have to adjust anyone's cursor after a regular add.
*/
if (!is_dup && add)
return;
/*
* Determine if a page was deleted. If this is a regular update
* (i.e., not is_dup) then the deleted page's number will be that in
* chg_pgno, and the pgno in the cursor will be different. If this
* was an onpage-duplicate, then the same conditions apply. If this
* was an off-page duplicate, then we need to verify if hcp->dpgno
* is the same (no delete) or different (delete) than chg_pgno.
*/
if (!is_dup || hcp->dpgno == PGNO_INVALID)
page_deleted =
chg_pgno != PGNO_INVALID && chg_pgno != hcp->pgno;
else
page_deleted =
chg_pgno != PGNO_INVALID && chg_pgno != hcp->dpgno;
hp = hcp->db_cursor->dbp->master->internal;
DB_THREAD_LOCK(hp->dbp);
for (cp = TAILQ_FIRST(&hp->dbp->curs_queue); cp != NULL;
cp = TAILQ_NEXT(cp, links)) {
if (cp->internal == hcp)
continue;
lcp = (HASH_CURSOR *)cp->internal;
if (!is_dup && lcp->pgno != chg_pgno)
continue;
if (is_dup) {
if (F_ISSET(hcp, H_DELETED) && lcp->pgno != chg_pgno)
continue;
if (!F_ISSET(hcp, H_DELETED) && lcp->dpgno != chg_pgno)
continue;
}
if (page_deleted) {
if (is_dup) {
lcp->dpgno = hcp->dpgno;
lcp->dndx = hcp->dndx;
} else {
lcp->pgno = hcp->pgno;
lcp->bndx = hcp->bndx;
lcp->bucket = hcp->bucket;
}
F_CLR(lcp, H_ISDUP);
continue;
}
if (!is_dup && lcp->bndx > hcp->bndx)
lcp->bndx--;
else if (!is_dup && lcp->bndx == hcp->bndx)
F_SET(lcp, H_DELETED);
else if (is_dup && lcp->bndx == hcp->bndx) {
/* Assign dpgno in case there was page conversion. */
lcp->dpgno = hcp->dpgno;
if (add && lcp->dndx >= hcp->dndx )
lcp->dndx++;
else if (!add && lcp->dndx > hcp->dndx)
lcp->dndx--;
else if (!add && lcp->dndx == hcp->dndx)
F_SET(lcp, H_DELETED);
/* Now adjust on-page information. */
if (lcp->dpgno == PGNO_INVALID)
if (add) {
lcp->dup_tlen += len;
if (lcp->dndx > hcp->dndx)
lcp->dup_off += len;
} else {
lcp->dup_tlen -= len;
if (lcp->dndx > hcp->dndx)
lcp->dup_off -= len;
}
}
}
DB_THREAD_UNLOCK(hp->dbp);
}
/*
* __ham_hdup --
* This function gets called when we create a duplicate handle for a
* threaded DB. It should create the private part of the DB structure.
*
* PUBLIC: int __ham_hdup __P((DB *, DB *));
*/
int
__ham_hdup(orig, new)
DB *orig, *new;
{
DBC *curs;
HTAB *hashp;
int ret;
if ((hashp = (HTAB *)__db_malloc(sizeof(HTAB))) == NULL)
return (ENOMEM);
new->internal = hashp;
hashp->dbp = new;
hashp->hlock = 0;
hashp->hdr = NULL;
hashp->hash = ((HTAB *)orig->internal)->hash;
if ((hashp->split_buf = (PAGE *)__db_malloc(orig->pgsize)) == NULL)
return (ENOMEM);
hashp->local_errno = 0;
hashp->hash_accesses = 0;
hashp->hash_collisions = 0;
hashp->hash_expansions = 0;
hashp->hash_overflows = 0;
hashp->hash_bigpages = 0;
/* Initialize the cursor queue. */
ret = __ham_c_init(new, NULL, &curs);
TAILQ_INSERT_TAIL(&new->curs_queue, curs, links);
return (ret);
}