subversion/libsvn_fs_base/bdb/dbt.c

   1 /* dbt.c --- DBT-frobbing functions
   2  *
   3  * ====================================================================
   4  * Copyright (c) 2000-2004 CollabNet.  All rights reserved.
   5  *
   6  * This software is licensed as described in the file COPYING, which
   7  * you should have received as part of this distribution.  The terms
   8  * are also available at http://subversion.tigris.org/license-1.html.
   9  * If newer versions of this license are posted there, you may use a
  10  * newer version instead, at your option.
  11  *
  12  * This software consists of voluntary contributions made by many
  13  * individuals.  For exact contribution history, see the revision
  14  * history and logs, available at http://subversion.tigris.org/.
  15  * ====================================================================
  16  */
  17
  18 #include <stdlib.h>
  19 #include <string.h>
  20 #include <apr_pools.h>
  21
  22 #define APU_WANT_DB
  23 #include <apu_want.h>
  24
  25 #include "../id.h"
  26 #include "dbt.h"
  27
  28
  29 DBT *
  30 svn_fs_base__clear_dbt(DBT *dbt)
  31 {
  32   memset(dbt, 0, sizeof(*dbt));
  33
  34   return dbt;
  35 }
  36
  37
  38 DBT *svn_fs_base__nodata_dbt(DBT *dbt)
  39 {
  40   svn_fs_base__clear_dbt(dbt);
  41
  42   /* A `nodata' dbt is one which retrieves zero bytes from offset zero,
  43      and stores them in a zero-byte buffer in user-allocated memory.  */
  44   dbt->flags |= (DB_DBT_USERMEM | DB_DBT_PARTIAL);
  45   dbt->doff = dbt->dlen = 0;
  46
  47   return dbt;
  48 }
  49
  50
  51 DBT *
  52 svn_fs_base__set_dbt(DBT *dbt, const void *data, u_int32_t size)
  53 {
  54   svn_fs_base__clear_dbt(dbt);
  55
  56   dbt->data = (void *) data;
  57   dbt->size = size;
  58
  59   return dbt;
  60 }
  61
  62
  63 DBT *
  64 svn_fs_base__result_dbt(DBT *dbt)
  65 {
  66   svn_fs_base__clear_dbt(dbt);
  67   dbt->flags |= DB_DBT_MALLOC;
  68
  69   return dbt;
  70 }
  71
  72
  73 /* An APR pool cleanup function that simply applies `free' to its
  74    argument.  */
  75 static apr_status_t
  76 apr_free_cleanup(void *arg)
  77 {
  78   free(arg);
  79
  80   return 0;
  81 }
  82
  83
  84 DBT *
  85 svn_fs_base__track_dbt(DBT *dbt, apr_pool_t *pool)
  86 {
  87   if (dbt->data)
  88     apr_pool_cleanup_register(pool, dbt->data, apr_free_cleanup,
  89                               apr_pool_cleanup_null);
  90
  91   return dbt;
  92 }
  93
  94
  95 DBT *
  96 svn_fs_base__recno_dbt(DBT *dbt, db_recno_t *recno)
  97 {
  98   svn_fs_base__set_dbt(dbt, recno, sizeof(*recno));
  99   dbt->ulen = dbt->size;
 100   dbt->flags |= DB_DBT_USERMEM;
 101
 102   return dbt;
 103 }
 104
 105
 106 int
 107 svn_fs_base__compare_dbt(const DBT *a, const DBT *b)
 108 {
 109   int common_size = a->size > b->size ? b->size : a->size;
 110   int cmp = memcmp(a->data, b->data, common_size);
 111
 112   if (cmp)
 113     return cmp;
 114   else
 115     return a->size - b->size;
 116 }
 117
 118
 119 \f
 120 /* Building DBT's from interesting things.  */
 121
 122
 123 /* Set DBT to the unparsed form of ID; allocate memory from POOL.
 124    Return DBT.  */
 125 DBT *
 126 svn_fs_base__id_to_dbt(DBT *dbt,
 127                        const svn_fs_id_t *id,
 128                        apr_pool_t *pool)
 129 {
 130   svn_string_t *unparsed_id = svn_fs_base__id_unparse(id, pool);
 131   svn_fs_base__set_dbt(dbt, unparsed_id->data, unparsed_id->len);
 132   return dbt;
 133 }
 134
 135
 136 /* Set DBT to the unparsed form of SKEL; allocate memory from POOL.  */
 137 DBT *
 138 svn_fs_base__skel_to_dbt(DBT *dbt,
 139                          skel_t *skel,
 140                          apr_pool_t *pool)
 141 {
 142   svn_stringbuf_t *unparsed_skel = svn_fs_base__unparse_skel(skel, pool);
 143   svn_fs_base__set_dbt(dbt, unparsed_skel->data, unparsed_skel->len);
 144   return dbt;
 145 }
 146
 147
 148 /* Set DBT to the text of the null-terminated string STR.  DBT will
 149    refer to STR's storage.  Return DBT.  */
 150 DBT *
 151 svn_fs_base__str_to_dbt(DBT *dbt, const char *str)
 152 {
 153   svn_fs_base__set_dbt(dbt, str, strlen(str));
 154   return dbt;
 155 }