bt_put.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, 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. 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: bt_put.c,v 11.69 2002/08/06 06:11:12 bostic Exp $";
#endif /* not lint */

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

#include <string.h>
#endif

#include "db_int.h"
#include "dbinc/db_page.h"
#include "dbinc/btree.h"

static int __bam_build
	       __P((DBC *, u_int32_t, DBT *, PAGE *, u_int32_t, u_int32_t));
static int __bam_dup_convert __P((DBC *, PAGE *, u_int32_t));
static int __bam_ovput
	       __P((DBC *, u_int32_t, db_pgno_t, PAGE *, u_int32_t, DBT *));
static u_int32_t
	   __bam_partsize __P((DB *, u_int32_t, DBT *, PAGE *, u_int32_t));

/*
 * __bam_iitem --
 *	Insert an item into the tree.
 *
 * PUBLIC: int __bam_iitem __P((DBC *, DBT *, DBT *, u_int32_t, u_int32_t));
 */
int
__bam_iitem(dbc, key, data, op, flags)
	DBC *dbc;
	DBT *key, *data;
	u_int32_t op, flags;
{
	BKEYDATA *bk, bk_tmp;
	BTREE *t;
	BTREE_CURSOR *cp;
	DB *dbp;
	DBT bk_hdr, tdbt;
	DB_MPOOLFILE *mpf;
	PAGE *h;
	db_indx_t indx;
	u_int32_t data_size, have_bytes, need_bytes, needed;
	int cmp, bigkey, bigdata, dupadjust, padrec, replace, ret, was_deleted;

	COMPQUIET(bk, NULL);

	dbp = dbc->dbp;
	mpf = dbp->mpf;
	cp = (BTREE_CURSOR *)dbc->internal;
	t = dbp->bt_internal;
	h = cp->page;
	indx = cp->indx;
	dupadjust = replace = was_deleted = 0;

	/*
	 * Fixed-length records with partial puts: it's an error to specify
	 * anything other simple overwrite.
	 */
	if (F_ISSET(dbp, DB_AM_FIXEDLEN) &&
	    F_ISSET(data, DB_DBT_PARTIAL) && data->dlen != data->size) {
		data_size = data->size;
		goto len_err;
	}

	/*
	 * Figure out how much space the data will take, including if it's a
	 * partial record.
	 *
	 * Fixed-length records: it's an error to specify a record that's
	 * longer than the fixed-length, and we never require less than
	 * the fixed-length record size.
	 */
	data_size = F_ISSET(data, DB_DBT_PARTIAL) ?
	    __bam_partsize(dbp, op, data, h, indx) : data->size;
	padrec = 0;
	if (F_ISSET(dbp, DB_AM_FIXEDLEN)) {
		if (data_size > t->re_len) {
len_err:		__db_err(dbp->dbenv,
			    "Length improper for fixed length record %lu",
			    (u_long)data_size);
			return (EINVAL);
		}

		/* Records that are deleted anyway needn't be padded out. */
		if (!LF_ISSET(BI_DELETED) && data_size < t->re_len) {
			padrec = 1;
			data_size = t->re_len;
		}
	}

	/*
	 * Handle partial puts or short fixed-length records: build the
	 * real record.
	 */
	if (padrec || F_ISSET(data, DB_DBT_PARTIAL)) {
		tdbt = *data;
		if ((ret =
		    __bam_build(dbc, op, &tdbt, h, indx, data_size)) != 0)
			return (ret);
		data = &tdbt;
	}

	/*
	 * If the user has specified a duplicate comparison function, return
	 * an error if DB_CURRENT was specified and the replacement data
	 * doesn't compare equal to the current data.  This stops apps from
	 * screwing up the duplicate sort order.  We have to do this after
	 * we build the real record so that we're comparing the real items.
	 */
	if (op == DB_CURRENT && dbp->dup_compare != NULL) {
		if ((ret = __bam_cmp(dbp, data, h,
		    indx + (TYPE(h) == P_LBTREE ? O_INDX : 0),
		    dbp->dup_compare, &cmp)) != 0)
			return (ret);
		if (cmp != 0) {
			__db_err(dbp->dbenv,
			    "Current data differs from put data");
			return (EINVAL);
		}
	}

	/*
	 * If the key or data item won't fit on a page, we'll have to store
	 * them on overflow pages.
	 */
	needed = 0;
	bigdata = data_size > cp->ovflsize;
	switch (op) {
	case DB_KEYFIRST:
		/* We're adding a new key and data pair. */
		bigkey = key->size > cp->ovflsize;
		if (bigkey)
			needed += BOVERFLOW_PSIZE;
		else
			needed += BKEYDATA_PSIZE(key->size);
		if (bigdata)
			needed += BOVERFLOW_PSIZE;
		else
			needed += BKEYDATA_PSIZE(data_size);
		break;
	case DB_AFTER:
	case DB_BEFORE:
	case DB_CURRENT:
		/*
		 * We're either overwriting the data item of a key/data pair
		 * or we're creating a new on-page duplicate and only adding
		 * a data item.
		 *
		 * !!!
		 * We're not currently correcting for space reclaimed from
		 * already deleted items, but I don't think it's worth the
		 * complexity.
		 */
		bigkey = 0;
		if (op == DB_CURRENT) {
			bk = GET_BKEYDATA(dbp, h,
			    indx + (TYPE(h) == P_LBTREE ? O_INDX : 0));
			if (B_TYPE(bk->type) == B_KEYDATA)
				have_bytes = BKEYDATA_PSIZE(bk->len);
			else
				have_bytes = BOVERFLOW_PSIZE;
			need_bytes = 0;
		} else {
			have_bytes = 0;
			need_bytes = sizeof(db_indx_t);
		}
		if (bigdata)
			need_bytes += BOVERFLOW_PSIZE;
		else
			need_bytes += BKEYDATA_PSIZE(data_size);

		if (have_bytes < need_bytes)
			needed += need_bytes - have_bytes;
		break;
	default:
		return (__db_unknown_flag(dbp->dbenv, "__bam_iitem", op));
	}

	/*
	 * If there's not enough room, or the user has put a ceiling on the
	 * number of keys permitted in the page, split the page.
	 *
	 * XXX
	 * The t->bt_maxkey test here may be insufficient -- do we have to
	 * check in the btree split code, so we don't undo it there!?!?
	 */
	if (P_FREESPACE(dbp, h) < needed ||
	    (t->bt_maxkey != 0 && NUM_ENT(h) > t->bt_maxkey))
		return (DB_NEEDSPLIT);

	/*
	 * The code breaks it up into five cases:
	 *
	 * 1. Insert a new key/data pair.
	 * 2. Append a new data item (a new duplicate).
	 * 3. Insert a new data item (a new duplicate).
	 * 4. Delete and re-add the data item (overflow item).
	 * 5. Overwrite the data item.
	 */
	switch (op) {
	case DB_KEYFIRST:		/* 1. Insert a new key/data pair. */
		if (bigkey) {
			if ((ret = __bam_ovput(dbc,
			    B_OVERFLOW, PGNO_INVALID, h, indx, key)) != 0)
				return (ret);
		} else
			if ((ret = __db_pitem(dbc, h, indx,
			    BKEYDATA_SIZE(key->size), NULL, key)) != 0)
				return (ret);

		if ((ret = __bam_ca_di(dbc, PGNO(h), indx, 1)) != 0)
			return (ret);
		++indx;
		break;
	case DB_AFTER:			/* 2. Append a new data item. */
		if (TYPE(h) == P_LBTREE) {
			/* Copy the key for the duplicate and adjust cursors. */
			if ((ret =
			    __bam_adjindx(dbc, h, indx + P_INDX, indx, 1)) != 0)
				return (ret);
			if ((ret =
			    __bam_ca_di(dbc, PGNO(h), indx + P_INDX, 1)) != 0)
				return (ret);

			indx += 3;
			dupadjust = 1;

			cp->indx += 2;
		} else {
			++indx;
			cp->indx += 1;
		}
		break;
	case DB_BEFORE:			/* 3. Insert a new data item. */
		if (TYPE(h) == P_LBTREE) {
			/* Copy the key for the duplicate and adjust cursors. */
			if ((ret = __bam_adjindx(dbc, h, indx, indx, 1)) != 0)
				return (ret);
			if ((ret = __bam_ca_di(dbc, PGNO(h), indx, 1)) != 0)
				return (ret);

			++indx;
			dupadjust = 1;
		}
		break;
	case DB_CURRENT:
		 /*
		  * Clear the cursor's deleted flag.  The problem is that if
		  * we deadlock or fail while deleting the overflow item or
		  * replacing the non-overflow item, a subsequent cursor close
		  * will try and remove the item because the cursor's delete
		  * flag is set
		  */
		(void)__bam_ca_delete(dbp, PGNO(h), indx, 0);

		if (TYPE(h) == P_LBTREE) {
			++indx;
			dupadjust = 1;

			/*
			 * In a Btree deleted records aren't counted (deleted
			 * records are counted in a Recno because all accesses
			 * are based on record number).  If it's a Btree and
			 * it's a DB_CURRENT operation overwriting a previously
			 * deleted record, increment the record count.
			 */
			was_deleted = B_DISSET(bk->type);
		}

		/*
		 * 4. Delete and re-add the data item.
		 *
		 * If we're changing the type of the on-page structure, or we
		 * are referencing offpage items, we have to delete and then
		 * re-add the item.  We do not do any cursor adjustments here
		 * because we're going to immediately re-add the item into the
		 * same slot.
		 */
		if (bigdata || B_TYPE(bk->type) != B_KEYDATA) {
			if ((ret = __bam_ditem(dbc, h, indx)) != 0)
				return (ret);
			break;
		}

		/* 5. Overwrite the data item. */
		replace = 1;
		break;
	default:
		return (__db_unknown_flag(dbp->dbenv, "__bam_iitem", op));
	}

	/* Add the data. */
	if (bigdata) {
		/*
		 * We do not have to handle deleted (BI_DELETED) records
		 * in this case; the actual records should never be created.
		 */
		DB_ASSERT(!LF_ISSET(BI_DELETED));
		if ((ret = __bam_ovput(dbc,
		    B_OVERFLOW, PGNO_INVALID, h, indx, data)) != 0)
			return (ret);
	} else {
		if (LF_ISSET(BI_DELETED)) {
			B_TSET(bk_tmp.type, B_KEYDATA, 1);
			bk_tmp.len = data->size;
			bk_hdr.data = &bk_tmp;
			bk_hdr.size = SSZA(BKEYDATA, data);
			ret = __db_pitem(dbc, h, indx,
			    BKEYDATA_SIZE(data->size), &bk_hdr, data);
		} else if (replace)
			ret = __bam_ritem(dbc, h, indx, data);
		else
			ret = __db_pitem(dbc, h, indx,
			    BKEYDATA_SIZE(data->size), NULL, data);
		if (ret != 0)
			return (ret);
	}
	if ((ret = mpf->set(mpf, h, DB_MPOOL_DIRTY)) != 0)
		return (ret);

	/*
	 * Re-position the cursors if necessary and reset the current cursor
	 * to point to the new item.
	 */
	if (op != DB_CURRENT) {
		if ((ret = __bam_ca_di(dbc, PGNO(h), indx, 1)) != 0)
			return (ret);
		cp->indx = TYPE(h) == P_LBTREE ? indx - O_INDX : indx;
	}

	/*
	 * If we've changed the record count, update the tree.  There's no
	 * need to adjust the count if the operation not performed on the
	 * current record or when the current record was previously deleted.
	 */
	if (F_ISSET(cp, C_RECNUM) && (op != DB_CURRENT || was_deleted))
		if ((ret = __bam_adjust(dbc, 1)) != 0)
			return (ret);

	/*
	 * If a Btree leaf page is at least 50% full and we may have added or
	 * modified a duplicate data item, see if the set of duplicates takes
	 * up at least 25% of the space on the page.  If it does, move it onto
	 * its own page.
	 */
	if (dupadjust && P_FREESPACE(dbp, h) <= dbp->pgsize / 2) {
		if ((ret = __bam_dup_convert(dbc, h, indx - O_INDX)) != 0)
			return (ret);
	}

	/* If we've modified a recno file, set the flag. */
	if (dbc->dbtype == DB_RECNO)
		t->re_modified = 1;

	return (ret);
}

/*
 * __bam_partsize --
 *	Figure out how much space a partial data item is in total.
 */
static u_int32_t
__bam_partsize(dbp, op, data, h, indx)
	DB *dbp;
	u_int32_t op, indx;
	DBT *data;
	PAGE *h;
{
	BKEYDATA *bk;
	u_int32_t nbytes;

	/*
	 * If the record doesn't already exist, it's simply the data we're
	 * provided.
	 */
	if (op != DB_CURRENT)
		return (data->doff + data->size);

	/*
	 * Otherwise, it's the data provided plus any already existing data
	 * that we're not replacing.
	 */
	bk = GET_BKEYDATA(dbp, h, indx + (TYPE(h) == P_LBTREE ? O_INDX : 0));