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bt_get.c revision 1.1.1.2 
      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)
     38 static 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  */
     62 int
     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