bt_get.c revision 165903 
1/*-
2 * Copyright (c) 1990, 1993, 1994
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Mike Olson.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 4. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#if defined(LIBC_SCCS) && !defined(lint)
34static char sccsid[] = "@(#)bt_get.c	8.6 (Berkeley) 7/20/94";
35#endif /* LIBC_SCCS and not lint */
36#include <sys/cdefs.h>
37__FBSDID("$FreeBSD: head/lib/libc/db/btree/bt_get.c 165903 2007-01-09 00:28:16Z imp $");
38
39#include <sys/types.h>
40
41#include <errno.h>
42#include <stddef.h>
43#include <stdio.h>
44
45#include <db.h>
46#include "btree.h"
47
48/*
49 * __BT_GET -- Get a record from the btree.
50 *
51 * Parameters:
52 *	dbp:	pointer to access method
53 *	key:	key to find
54 *	data:	data to return
55 *	flag:	currently unused
56 *
57 * Returns:
58 *	RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
59 */
60int
61__bt_get(dbp, key, data, flags)
62	const DB *dbp;
63	const DBT *key;
64	DBT *data;
65	u_int flags;
66{
67	BTREE *t;
68	EPG *e;
69	int exact, status;
70
71	t = dbp->internal;
72
73	/* Toss any page pinned across calls. */
74	if (t->bt_pinned != NULL) {
75		mpool_put(t->bt_mp, t->bt_pinned, 0);
76		t->bt_pinned = NULL;
77	}
78
79	/* Get currently doesn't take any flags. */
80	if (flags) {
81		errno = EINVAL;
82		return (RET_ERROR);
83	}
84
85	if ((e = __bt_search(t, key, &exact)) == NULL)
86		return (RET_ERROR);
87	if (!exact) {
88		mpool_put(t->bt_mp, e->page, 0);
89		return (RET_SPECIAL);
90	}
91
92	status = __bt_ret(t, e, NULL, NULL, data, &t->bt_rdata, 0);
93
94	/*
95	 * If the user is doing concurrent access, we copied the
96	 * key/data, toss the page.
97	 */
98	if (F_ISSET(t, B_DB_LOCK))
99		mpool_put(t->bt_mp, e->page, 0);
100	else
101		t->bt_pinned = e->page;
102	return (status);
103}
104