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bt_get.c revision 1.12 
      1 /*	$NetBSD: bt_get.c,v 1.12 2008/09/10 17:52:35 joerg Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1990, 1993, 1994
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This code is derived from software contributed to Berkeley by
      8  * Mike Olson.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. Neither the name of the University nor the names of its contributors
     19  *    may be used to endorse or promote products derived from this software
     20  *    without specific prior written permission.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     32  * SUCH DAMAGE.
     33  */
     34 
     35 #include <sys/cdefs.h>
     36 __RCSID("$NetBSD: bt_get.c,v 1.12 2008/09/10 17:52:35 joerg Exp $");
     37 
     38 #include "namespace.h"
     39 #include <sys/types.h>
     40 
     41 #include <assert.h>
     42 #include <errno.h>
     43 #include <stddef.h>
     44 #include <stdio.h>
     45 
     46 #include <db.h>
     47 #include "btree.h"
     48 
     49 /*
     50  * __BT_GET -- Get a record from the btree.
     51  *
     52  * Parameters:
     53  *	dbp:	pointer to access method
     54  *	key:	key to find
     55  *	data:	data to return
     56  *	flag:	currently unused
     57  *
     58  * Returns:
     59  *	RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
     60  */
     61 int
     62 __bt_get(const DB *dbp, const DBT *key, DBT *data, u_int flags)
     63 {
     64 	BTREE *t;
     65 	EPG *e;
     66 	int exact, status;
     67 
     68 	t = dbp->internal;
     69 
     70 	/* Toss any page pinned across calls. */
     71 	if (t->bt_pinned != NULL) {
     72 		mpool_put(t->bt_mp, t->bt_pinned, 0);
     73 		t->bt_pinned = NULL;
     74 	}
     75 
     76 	/* Get currently doesn't take any flags. */
     77 	if (flags) {
     78 		errno = EINVAL;
     79 		return (RET_ERROR);
     80 	}
     81 
     82 	if ((e = __bt_search(t, key, &exact)) == NULL)
     83 		return (RET_ERROR);
     84 	if (!exact) {
     85 		mpool_put(t->bt_mp, e->page, 0);
     86 		return (RET_SPECIAL);
     87 	}
     88 
     89 	status = __bt_ret(t, e, NULL, NULL, data, &t->bt_rdata, 0);
     90 
     91 	/*
     92 	 * If the user is doing concurrent access, we copied the
     93 	 * key/data, toss the page.
     94 	 */
     95 	if (F_ISSET(t, B_DB_LOCK))
     96 		mpool_put(t->bt_mp, e->page, 0);
     97 	else
     98 		t->bt_pinned = e->page;
     99 	return (status);
    100 }
    101