db/btree/bt_get.c

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