hash.c

这是linux下运行的mysql软件包,可用于linux 下安装 php + mysql + apach 的网络配置

/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996-2002
 *	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. 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 "db_config.h"

#ifndef lint
static const char revid[] = "$Id: hash.c,v 11.166 2002/08/06 06:11:25 bostic Exp $";
#endif /* not lint */

#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>

#include <stdlib.h>
#include <string.h>
#endif

#include "db_int.h"
#include "dbinc/db_page.h"
#include "dbinc/db_shash.h"
#include "dbinc/btree.h"
#include "dbinc/hash.h"
#include "dbinc/lock.h"

static int  __ham_bulk __P((DBC *, DBT *, u_int32_t));
static int  __ham_c_close __P((DBC *, db_pgno_t, int *));
static int  __ham_c_del __P((DBC *));
static int  __ham_c_destroy __P((DBC *));
static int  __ham_c_get __P((DBC *, DBT *, DBT *, u_int32_t, db_pgno_t *));
static int  __ham_c_put __P((DBC *, DBT *, DBT *, u_int32_t, db_pgno_t *));
static int  __ham_c_writelock __P((DBC *));
static int  __ham_dup_return __P((DBC *, DBT *, u_int32_t));
static int  __ham_expand_table __P((DBC *));
static int  __ham_lookup __P((DBC *,
		const DBT *, u_int32_t, db_lockmode_t, db_pgno_t *));
static int  __ham_overwrite __P((DBC *, DBT *, u_int32_t));

/*
 * __ham_quick_delete --
 *	When performing a DB->del operation that does not involve secondary
 *	indices and is not removing an off-page duplicate tree, we can
 *	speed things up substantially by removing the entire duplicate
 *	set, if any is present, in one operation, rather than by conjuring
 *	up and deleting each of the items individually.  (All are stored
 *	in one big HKEYDATA structure.)  We don't bother to distinguish
 *	on-page duplicate sets from single, non-dup items;  they're deleted
 *	in exactly the same way.
 *
 *	This function is called by __db_delete when the appropriate
 *	conditions are met, and it performs the delete in the optimized way.
 *
 *	The cursor should be set to the first item in the duplicate
 *	set, or to the sole key/data pair when the key does not have a
 *	duplicate set, before the function is called.
 *
 * PUBLIC: int __ham_quick_delete __P((DBC *));
 */
int
__ham_quick_delete(dbc)
	DBC *dbc;
{
	int ret, t_ret;

	if ((ret = __ham_get_meta(dbc)) != 0)
		return (ret);

	/* Assert that we're not using secondary indices. */
	DB_ASSERT(!F_ISSET(dbc->dbp, DB_AM_SECONDARY));
	/*
	 * We should assert that we're not a primary either, but that
	 * would require grabbing the dbp's mutex, so we don't bother.
	 */

	/* Assert that we're set, but not to an off-page duplicate. */
	DB_ASSERT(IS_INITIALIZED(dbc));
	DB_ASSERT(((HASH_CURSOR *)dbc->internal)->opd == NULL);

	ret = __ham_del_pair(dbc, 1);

	if ((t_ret = __ham_release_meta(dbc)) != 0 && ret == 0)
		ret = t_ret;

	return (ret);
}

/* ****************** CURSORS ********************************** */
/*
 * __ham_c_init --
 *	Initialize the hash-specific portion of a cursor.
 *
 * PUBLIC: int __ham_c_init __P((DBC *));
 */
int
__ham_c_init(dbc)
	DBC *dbc;
{
	DB_ENV *dbenv;
	HASH_CURSOR *new_curs;
	int ret;

	dbenv = dbc->dbp->dbenv;
	if ((ret = __os_calloc(dbenv,
	    1, sizeof(struct cursor_t), &new_curs)) != 0)
		return (ret);
	if ((ret = __os_malloc(dbenv,
	    dbc->dbp->pgsize, &new_curs->split_buf)) != 0) {
		__os_free(dbenv, new_curs);
		return (ret);
	}

	dbc->internal = (DBC_INTERNAL *) new_curs;
	dbc->c_close = __db_c_close;
	dbc->c_count = __db_c_count;
	dbc->c_del = __db_c_del;
	dbc->c_dup = __db_c_dup;
	dbc->c_get = dbc->c_real_get = __db_c_get;
	dbc->c_pget = __db_c_pget;
	dbc->c_put = __db_c_put;
	dbc->c_am_bulk = __ham_bulk;
	dbc->c_am_close = __ham_c_close;
	dbc->c_am_del = __ham_c_del;
	dbc->c_am_destroy = __ham_c_destroy;
	dbc->c_am_get = __ham_c_get;
	dbc->c_am_put = __ham_c_put;
	dbc->c_am_writelock = __ham_c_writelock;

	__ham_item_init(dbc);

	return (0);
}

/*
 * __ham_c_close --
 *	Close down the cursor from a single use.
 */
static int
__ham_c_close(dbc, root_pgno, rmroot)
	DBC *dbc;
	db_pgno_t root_pgno;
	int *rmroot;
{
	DB_MPOOLFILE *mpf;
	HASH_CURSOR *hcp;
	HKEYDATA *dp;
	int doroot, gotmeta, ret, t_ret;
	u_int32_t dirty;

	COMPQUIET(rmroot, 0);
	mpf = dbc->dbp->mpf;
	dirty = 0;
	doroot = gotmeta = ret = 0;
	hcp = (HASH_CURSOR *) dbc->internal;

	/* Check for off page dups. */
	if (dbc->internal->opd != NULL) {
		if ((ret = __ham_get_meta(dbc)) != 0)
			goto done;
		gotmeta = 1;
		if ((ret = __ham_get_cpage(dbc, DB_LOCK_READ)) != 0)
			goto out;
		dp = (HKEYDATA *)H_PAIRDATA(dbc->dbp, hcp->page, hcp->indx);

		/* If its not a dup we aborted before we changed it. */
		if (HPAGE_PTYPE(dp) == H_OFFDUP)
			memcpy(&root_pgno,
			    HOFFPAGE_PGNO(dp), sizeof(db_pgno_t));
		else
			root_pgno = PGNO_INVALID;

		if ((ret =
		    hcp->opd->c_am_close(hcp->opd, root_pgno, &doroot)) != 0)
			goto out;
		if (doroot != 0) {
			if ((ret = __ham_del_pair(dbc, 1)) != 0)
				goto out;
			dirty = DB_MPOOL_DIRTY;
		}
	}

out:	if (hcp->page != NULL && (t_ret =
	    mpf->put(mpf, hcp->page, dirty)) != 0 && ret == 0)
		ret = t_ret;
	if (gotmeta != 0 && (t_ret = __ham_release_meta(dbc)) != 0 && ret == 0)
		ret = t_ret;

done:
	__ham_item_init(dbc);
	return (ret);
}

/*
 * __ham_c_destroy --
 *	Cleanup the access method private part of a cursor.
 */
static int
__ham_c_destroy(dbc)
	DBC *dbc;
{
	HASH_CURSOR *hcp;

	hcp = (HASH_CURSOR *)dbc->internal;
	if (hcp->split_buf != NULL)
		__os_free(dbc->dbp->dbenv, hcp->split_buf);
	__os_free(dbc->dbp->dbenv, hcp);

	return (0);
}

/*
 * __ham_c_count --
 *	Return a count of on-page duplicates.
 *
 * PUBLIC: int __ham_c_count __P((DBC *, db_recno_t *));
 */
int
__ham_c_count(dbc, recnop)
	DBC *dbc;
	db_recno_t *recnop;
{
	DB *dbp;
	DB_MPOOLFILE *mpf;
	HASH_CURSOR *hcp;
	db_indx_t len;
	db_recno_t recno;
	int ret, t_ret;
	u_int8_t *p, *pend;

	dbp = dbc->dbp;
	mpf = dbp->mpf;
	hcp = (HASH_CURSOR *)dbc->internal;

	recno = 0;

	if ((ret = __ham_get_cpage(dbc, DB_LOCK_READ)) != 0)
		return (ret);

	switch (HPAGE_PTYPE(H_PAIRDATA(dbp, hcp->page, hcp->indx))) {
	case H_KEYDATA:
	case H_OFFPAGE:
		recno = 1;
		break;
	case H_DUPLICATE:
		p = HKEYDATA_DATA(H_PAIRDATA(dbp, hcp->page, hcp->indx));
		pend = p +
		    LEN_HDATA(dbp, hcp->page, dbp->pgsize, hcp->indx);
		for (; p < pend; recno++) {
			/* p may be odd, so copy rather than just dereffing */
			memcpy(&len, p, sizeof(db_indx_t));
			p += 2 * sizeof(db_indx_t) + len;
		}

		break;
	default:
		ret = __db_pgfmt(dbp->dbenv, hcp->pgno);
		goto err;
	}

	*recnop = recno;

err:	if ((t_ret = mpf->put(mpf, hcp->page, 0)) != 0 && ret == 0)
		ret = t_ret;
	hcp->page = NULL;
	return (ret);
}

static int
__ham_c_del(dbc)
	DBC *dbc;
{
	DB *dbp;
	DBT repldbt;
	DB_MPOOLFILE *mpf;
	HASH_CURSOR *hcp;
	int ret, t_ret;

	dbp = dbc->dbp;
	mpf = dbp->mpf;
	hcp = (HASH_CURSOR *)dbc->internal;

	if (F_ISSET(hcp, H_DELETED))
		return (DB_NOTFOUND);

	if ((ret = __ham_get_meta(dbc)) != 0)
		goto out;

	if ((ret = __ham_get_cpage(dbc, DB_LOCK_WRITE)) != 0)
		goto out;

	/* Off-page duplicates. */
	if (HPAGE_TYPE(dbp, hcp->page, H_DATAINDEX(hcp->indx)) == H_OFFDUP)
		goto out;

	if (F_ISSET(hcp, H_ISDUP)) { /* On-page duplicate. */
		if (hcp->dup_off == 0 &&
		    DUP_SIZE(hcp->dup_len) == LEN_HDATA(dbp, hcp->page,
		    hcp->hdr->dbmeta.pagesize, hcp->indx))
			ret = __ham_del_pair(dbc, 1);
		else {
			repldbt.flags = 0;
			F_SET(&repldbt, DB_DBT_PARTIAL);
			repldbt.doff = hcp->dup_off;
			repldbt.dlen = DUP_SIZE(hcp->dup_len);
			repldbt.size = 0;
			repldbt.data = HKEYDATA_DATA(H_PAIRDATA(dbp, hcp->page,
			    hcp->indx));
			if ((ret = __ham_replpair(dbc, &repldbt, 0)) == 0) {
				hcp->dup_tlen -= DUP_SIZE(hcp->dup_len);
				F_SET(hcp, H_DELETED);
				ret = __ham_c_update(dbc,
				    DUP_SIZE(hcp->dup_len), 0, 1);
			}
		}

	} else /* Not a duplicate */
		ret = __ham_del_pair(dbc, 1);

out:	if (hcp->page != NULL) {
		if ((t_ret = mpf->put(mpf,
		    hcp->page, ret == 0 ? DB_MPOOL_DIRTY : 0)) && ret == 0)
			ret = t_ret;
		hcp->page = NULL;
	}
	if ((t_ret = __ham_release_meta(dbc)) != 0 && ret == 0)
		ret = t_ret;
	return (ret);
}

/*
 * __ham_c_dup --
 *	Duplicate a hash cursor, such that the new one holds appropriate
 *	locks for the position of the original.
 *
 * PUBLIC: int __ham_c_dup __P((DBC *, DBC *));
 */
int
__ham_c_dup(orig_dbc, new_dbc)
	DBC *orig_dbc, *new_dbc;
{
	HASH_CURSOR *orig, *new;

	orig = (HASH_CURSOR *)orig_dbc->internal;
	new = (HASH_CURSOR *)new_dbc->internal;

	new->bucket = orig->bucket;
	new->lbucket = orig->lbucket;
	new->dup_off = orig->dup_off;
	new->dup_len = orig->dup_len;
	new->dup_tlen = orig->dup_tlen;

	if (F_ISSET(orig, H_DELETED))
		F_SET(new, H_DELETED);
	if (F_ISSET(orig, H_ISDUP))
		F_SET(new, H_ISDUP);

	/*
	 * If the old cursor held a lock and we're not in transactions, get one
	 * for the new one.   The reason that we don't need a new lock if we're
	 * in a transaction is because we already hold a lock and will continue
	 * to do so until commit, so there is no point in reaquiring it. We
	 * don't know if the old lock was a read or write lock, but it doesn't
	 * matter. We'll get a read lock.  We know that this locker already
	 * holds a lock of the correct type, so if we need a write lock and
	 * request it, we know that we'll get it.
	 */
	if (!LOCK_ISSET(orig->lock) || orig_dbc->txn != NULL)
		return (0);

	return (__ham_lock_bucket(new_dbc, DB_LOCK_READ));
}

static int
__ham_c_get(dbc, key, data, flags, pgnop)
	DBC *dbc;
	DBT *key;
	DBT *data;
	u_int32_t flags;
	db_pgno_t *pgnop;
{
	DB *dbp;
	DB_MPOOLFILE *mpf;
	HASH_CURSOR *hcp;
	db_lockmode_t lock_type;
	int get_key, ret, t_ret;

	hcp = (HASH_CURSOR *)dbc->internal;
	dbp = dbc->dbp;
	mpf = dbp->mpf;

	/* Clear OR'd in additional bits so we can check for flag equality. */
	if (F_ISSET(dbc, DBC_RMW))
		lock_type = DB_LOCK_WRITE;
	else
		lock_type = DB_LOCK_READ;

	if ((ret = __ham_get_meta(dbc)) != 0)
		return (ret);
	hcp->seek_size = 0;

	ret = 0;
	get_key = 1;
	switch (flags) {
	case DB_PREV_NODUP:
		F_SET(hcp, H_NEXT_NODUP);
		/* FALLTHROUGH */
	case DB_PREV:
		if (IS_INITIALIZED(dbc)) {
			ret = __ham_item_prev(dbc, lock_type, pgnop);
			break;
		}
		/* FALLTHROUGH */
	case DB_LAST:
		ret = __ham_item_last(dbc, lock_type, pgnop);
		break;
	case DB_NEXT_NODUP:
		F_SET(hcp, H_NEXT_NODUP);
		/* FALLTHROUGH */
	case DB_NEXT:
		if (IS_INITIALIZED(dbc)) {
			ret = __ham_item_next(dbc, lock_type, pgnop);
			break;
		}
		/* FALLTHROUGH */
	case DB_FIRST:
		ret = __ham_item_first(dbc, lock_type, pgnop);
		break;
	case DB_NEXT_DUP:
		/* cgetchk has already determined that the cursor is set. */
		F_SET(hcp, H_DUPONLY);
		ret = __ham_item_next(dbc, lock_type, pgnop);
		break;
	case DB_SET:
	case DB_SET_RANGE:
	case DB_GET_BOTH:
	case DB_GET_BOTH_RANGE:
		ret = __ham_lookup(dbc, key, 0, lock_type, pgnop);
		get_key = 0;
		break;
	case DB_GET_BOTHC:
		F_SET(hcp, H_DUPONLY);

		ret = __ham_item_next(dbc, lock_type, pgnop);
		get_key = 0;
		break;
	case DB_CURRENT:
		/* cgetchk has already determined that the cursor is set. */
		if (F_ISSET(hcp, H_DELETED)) {
			ret = DB_KEYEMPTY;
			goto err;
		}

		ret = __ham_item(dbc, lock_type, pgnop);
		break;
	}

	/*
	 * Must always enter this loop to do error handling and
	 * check for big key/data pair.
	 */
	for (;;) {
		if (ret != 0 && ret != DB_NOTFOUND)
			goto err;
		else if (F_ISSET(hcp, H_OK)) {
			if (*pgnop == PGNO_INVALID)
				ret = __ham_dup_return(dbc, data, flags);
			break;
		} else if (!F_ISSET(hcp, H_NOMORE)) {
			__db_err(dbp->dbenv,
			    "H_NOMORE returned to __ham_c_get");
			ret = EINVAL;
			break;
		}

		/*
		 * Ran out of entries in a bucket; change buckets.
		 */
		switch (flags) {
			case DB_LAST:
			case DB_PREV: