main/db1-ast/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. 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 "../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 }