bt_get.c revision 14273 
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 * 3. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by the University of
19 *	California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#if defined(LIBC_SCCS) && !defined(lint)
38static char sccsid[] = "@(#)bt_get.c	8.6 (Berkeley) 7/20/94";
39#endif /* LIBC_SCCS and not lint */
40
41#include <sys/types.h>
42
43#include <errno.h>
44#include <stddef.h>
45#include <stdio.h>
46
47#include <db.h>
48#include "btree.h"
49
50/*
51 * __BT_GET -- Get a record from the btree.
52 *
53 * Parameters:
54 *	dbp:	pointer to access method
55 *	key:	key to find
56 *	data:	data to return
57 *	flag:	currently unused
58 *
59 * Returns:
60 *	RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
61 */
62int
63__bt_get(dbp, key, data, flags)
64	const DB *dbp;
65	const DBT *key;
66	DBT *data;
67	u_int flags;
68{
69	BTREE *t;
70	EPG *e;
71	int exact, status;
72
73	t = dbp->internal;
74
75	/* Toss any page pinned across calls. */
76	if (t->bt_pinned != NULL) {
77		mpool_put(t->bt_mp, t->bt_pinned, 0);
78		t->bt_pinned = NULL;
79	}
80
81	/* Get currently doesn't take any flags. */
82	if (flags) {
83		errno = EINVAL;
84		return (RET_ERROR);
85	}
86
87	if ((e = __bt_search(t, key, &exact)) == NULL)
88		return (RET_ERROR);
89	if (!exact) {
90		mpool_put(t->bt_mp, e->page, 0);
91		return (RET_SPECIAL);
92	}
93
94	status = __bt_ret(t, e, NULL, NULL, data, &t->bt_rdata, 0);
95
96	/*
97	 * If the user is doing concurrent access, we copied the
98	 * key/data, toss the page.
99	 */
100	if (F_ISSET(t, B_DB_LOCK))
101		mpool_put(t->bt_mp, e->page, 0);
102	else
103		t->bt_pinned = e->page;
104	return (status);
105}
106