xref: /freebsd/lib/libc/db/btree/bt_get.c (revision b1f9167f94059fd55c630891d359bcff987bd7eb)
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)
34 static 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("$FreeBSD$");
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  */
60 int
61 __bt_get(const DB *dbp, const DBT *key, DBT *data, u_int flags)
62 {
63 	BTREE *t;
64 	EPG *e;
65 	int exact, status;
66 
67 	t = dbp->internal;
68 
69 	/* Toss any page pinned across calls. */
70 	if (t->bt_pinned != NULL) {
71 		mpool_put(t->bt_mp, t->bt_pinned, 0);
72 		t->bt_pinned = NULL;
73 	}
74 
75 	/* Get currently doesn't take any flags. */
76 	if (flags) {
77 		errno = EINVAL;
78 		return (RET_ERROR);
79 	}
80 
81 	if ((e = __bt_search(t, key, &exact)) == NULL)
82 		return (RET_ERROR);
83 	if (!exact) {
84 		mpool_put(t->bt_mp, e->page, 0);
85 		return (RET_SPECIAL);
86 	}
87 
88 	status = __bt_ret(t, e, NULL, NULL, data, &t->bt_rdata, 0);
89 
90 	/*
91 	 * If the user is doing concurrent access, we copied the
92 	 * key/data, toss the page.
93 	 */
94 	if (F_ISSET(t, B_DB_LOCK))
95 		mpool_put(t->bt_mp, e->page, 0);
96 	else
97 		t->bt_pinned = e->page;
98 	return (status);
99 }
100