db/btree/bt_get.c

   1 /*
   2  * Copyright (c) 2003 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*-
  26  * Copyright (c) 1990, 1993, 1994
  27  *      The Regents of the University of California.  All rights reserved.
  28  *
  29  * This code is derived from software contributed to Berkeley by
  30  * Mike Olson.
  31  *
  32  * Redistribution and use in source and binary forms, with or without
  33  * modification, are permitted provided that the following conditions
  34  * are met:
  35  * 1. Redistributions of source code must retain the above copyright
  36  *    notice, this list of conditions and the following disclaimer.
  37  * 2. Redistributions in binary form must reproduce the above copyright
  38  *    notice, this list of conditions and the following disclaimer in the
  39  *    documentation and/or other materials provided with the distribution.
  40  * 3. All advertising materials mentioning features or use of this software
  41  *    must display the following acknowledgement:
  42  *      This product includes software developed by the University of
  43  *      California, Berkeley and its contributors.
  44  * 4. Neither the name of the University nor the names of its contributors
  45  *    may be used to endorse or promote products derived from this software
  46  *    without specific prior written permission.
  47  *
  48  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  58  * SUCH DAMAGE.
  59  */
  60
  61 #if defined(LIBC_SCCS) && !defined(lint)
  62 static char sccsid[] = "@(#)bt_get.c    8.6 (Berkeley) 7/20/94";
  63 #endif /* LIBC_SCCS and not lint */
  64 #include <sys/cdefs.h>
  65
  66 #include <sys/types.h>
  67
  68 #include <errno.h>
  69 #include <stddef.h>
  70 #include <stdio.h>
  71
  72 #include <db.h>
  73 #include "btree.h"
  74
  75 /*
  76  * __BT_GET -- Get a record from the btree.
  77  *
  78  * Parameters:
  79  *      dbp:    pointer to access method
  80  *      key:    key to find
  81  *      data:   data to return
  82  *      flag:   currently unused
  83  *
  84  * Returns:
  85  *      RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
  86  */
  87 int
  88 __bt_get(dbp, key, data, flags)
  89         const DB *dbp;
  90         const DBT *key;
  91         DBT *data;
  92         u_int flags;
  93 {
  94         BTREE *t;
  95         EPG *e;
  96         int exact, status;
  97
  98         t = dbp->internal;
  99
 100         /* Toss any page pinned across calls. */
 101         if (t->bt_pinned != NULL) {
 102                 mpool_put(t->bt_mp, t->bt_pinned, 0);
 103                 t->bt_pinned = NULL;
 104         }
 105
 106         /* Get currently doesn't take any flags. */
 107         if (flags) {
 108                 errno = EINVAL;
 109                 return (RET_ERROR);
 110         }
 111
 112         if ((e = __bt_search(t, key, &exact)) == NULL)
 113                 return (RET_ERROR);
 114         if (!exact) {
 115                 mpool_put(t->bt_mp, e->page, 0);
 116                 return (RET_SPECIAL);
 117         }
 118
 119         status = __bt_ret(t, e, NULL, NULL, data, &t->bt_rdata, 0);
 120
 121         /*
 122          * If the user is doing concurrent access, we copied the
 123          * key/data, toss the page.
 124          */
 125         if (F_ISSET(t, B_DB_LOCK))
 126                 mpool_put(t->bt_mp, e->page, 0);
 127         else
 128                 t->bt_pinned = e->page;
 129         return (status);
 130 }