lib/libc/db/btree/bt_get.c

   1 /*      $NetBSD: bt_get.c,v 1.13 2008/09/11 12:58:00 joerg Exp $        */
   2
   3 /*-
   4  * Copyright (c) 1990, 1993, 1994
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Mike Olson.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #if HAVE_NBTOOL_CONFIG_H
  36 #include "nbtool_config.h"
  37 #endif
  38
  39 #include <sys/cdefs.h>
  40 __RCSID("$NetBSD: bt_get.c,v 1.13 2008/09/11 12:58:00 joerg Exp $");
  41
  42 #include "namespace.h"
  43 #include <sys/types.h>
  44
  45 #include <assert.h>
  46 #include <errno.h>
  47 #include <stddef.h>
  48 #include <stdio.h>
  49
  50 #include <db.h>
  51 #include "btree.h"
  52
  53 /*
  54  * __BT_GET -- Get a record from the btree.
  55  *
  56  * Parameters:
  57  *      dbp:    pointer to access method
  58  *      key:    key to find
  59  *      data:   data to return
  60  *      flag:   currently unused
  61  *
  62  * Returns:
  63  *      RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
  64  */
  65 int
  66 __bt_get(const DB *dbp, const DBT *key, DBT *data, u_int flags)
  67 {
  68         BTREE *t;
  69         EPG *e;
  70         int exact, status;
  71
  72         t = dbp->internal;
  73
  74         /* Toss any page pinned across calls. */
  75         if (t->bt_pinned != NULL) {
  76                 mpool_put(t->bt_mp, t->bt_pinned, 0);
  77                 t->bt_pinned = NULL;
  78         }
  79
  80         /* Get currently doesn't take any flags. */
  81         if (flags) {
  82                 errno = EINVAL;
  83                 return (RET_ERROR);
  84         }
  85
  86         if ((e = __bt_search(t, key, &exact)) == NULL)
  87                 return (RET_ERROR);
  88         if (!exact) {
  89                 mpool_put(t->bt_mp, e->page, 0);
  90                 return (RET_SPECIAL);
  91         }
  92
  93         status = __bt_ret(t, e, NULL, NULL, data, &t->bt_rdata, 0);
  94
  95         /*
  96          * If the user is doing concurrent access, we copied the
  97          * key/data, toss the page.
  98          */
  99         if (F_ISSET(t, B_DB_LOCK))
 100                 mpool_put(t->bt_mp, e->page, 0);
 101         else
 102                 t->bt_pinned = e->page;
 103         return (status);
 104 }