lib/libc/db/btree/bt_get.c

   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. 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  * @(#)bt_get.c 8.6 (Berkeley) 7/20/94
  33  * $DragonFly: src/lib/libc/db/btree/bt_get.c,v 1.4 2005/11/12 23:01:54 swildner Exp $
  34  */
  35
  36 #include <sys/types.h>
  37
  38 #include <errno.h>
  39 #include <stddef.h>
  40 #include <stdio.h>
  41
  42 #include <db.h>
  43 #include "btree.h"
  44
  45 /*
  46  * __BT_GET -- Get a record from the btree.
  47  *
  48  * Parameters:
  49  *      dbp:    pointer to access method
  50  *      key:    key to find
  51  *      data:   data to return
  52  *      flag:   currently unused
  53  *
  54  * Returns:
  55  *      RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key not found.
  56  */
  57 int
  58 __bt_get(const DB *dbp, const DBT *key, DBT *data, u_int flags)
  59 {
  60         BTREE *t;
  61         EPG *e;
  62         int exact, status;
  63
  64         t = dbp->internal;
  65
  66         /* Toss any page pinned across calls. */
  67         if (t->bt_pinned != NULL) {
  68                 mpool_put(t->bt_mp, t->bt_pinned, 0);
  69                 t->bt_pinned = NULL;
  70         }
  71
  72         /* Get currently doesn't take any flags. */
  73         if (flags) {
  74                 errno = EINVAL;
  75                 return (RET_ERROR);
  76         }
  77
  78         if ((e = __bt_search(t, key, &exact)) == NULL)
  79                 return (RET_ERROR);
  80         if (!exact) {
  81                 mpool_put(t->bt_mp, e->page, 0);
  82                 return (RET_SPECIAL);
  83         }
  84
  85         status = __bt_ret(t, e, NULL, NULL, data, &t->bt_rdata, 0);
  86
  87         /*
  88          * If the user is doing concurrent access, we copied the
  89          * key/data, toss the page.
  90          */
  91         if (F_ISSET(t, B_DB_LOCK))
  92                 mpool_put(t->bt_mp, e->page, 0);
  93         else
  94                 t->bt_pinned = e->page;
  95         return (status);
  96 }