granicus.if.org Git - postgresql/blob - src/backend/utils/adt/tid.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * tid.c
   4  *        Functions for the built-in type tuple id
   5  *
   6  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  *
  10  * IDENTIFICATION
  11  *        $Header: /cvsroot/pgsql/src/backend/utils/adt/tid.c,v 1.17 2000/05/29 01:59:08 tgl Exp $
  12  *
  13  * NOTES
  14  *        input routine largely stolen from boxin().
  15  *
  16  *-------------------------------------------------------------------------
  17  */
  18
  19 #include "postgres.h"
  20
  21 #include "access/heapam.h"
  22 #include "utils/builtins.h"
  23
  24 #define LDELIM                  '('
  25 #define RDELIM                  ')'
  26 #define DELIM                   ','
  27 #define NTIDARGS                2
  28
  29 /* ----------------------------------------------------------------
  30  *              tidin
  31  * ----------------------------------------------------------------
  32  */
  33 ItemPointer
  34 tidin(const char *str)
  35 {
  36         const char *p,
  37                            *coord[NTIDARGS];
  38         int                     i;
  39         ItemPointer result;
  40
  41         BlockNumber blockNumber;
  42         OffsetNumber offsetNumber;
  43
  44         if (str == NULL)
  45                 return NULL;
  46
  47         for (i = 0, p = str; *p && i < NTIDARGS && *p != RDELIM; p++)
  48                 if (*p == DELIM || (*p == LDELIM && !i))
  49                         coord[i++] = p + 1;
  50
  51         /* if (i < NTIDARGS - 1) */
  52         if (i < NTIDARGS)
  53         {
  54                 elog(ERROR, "%s invalid tid format", str);
  55                 return NULL;
  56         }
  57
  58         blockNumber = (BlockNumber) atoi(coord[0]);
  59         offsetNumber = (OffsetNumber) atoi(coord[1]);
  60
  61         result = (ItemPointer) palloc(sizeof(ItemPointerData));
  62
  63         ItemPointerSet(result, blockNumber, offsetNumber);
  64
  65         return result;
  66 }
  67
  68 /* ----------------------------------------------------------------
  69  *              tidout
  70  * ----------------------------------------------------------------
  71  */
  72 char *
  73 tidout(ItemPointer itemPtr)
  74 {
  75         BlockNumber blockNumber;
  76         OffsetNumber offsetNumber;
  77         BlockId         blockId;
  78         char            buf[32];
  79         char       *str;
  80         static char *invalidTid = "()";
  81
  82         if (!itemPtr || !ItemPointerIsValid(itemPtr))
  83         {
  84                 str = palloc(strlen(invalidTid));
  85                 strcpy(str, invalidTid);
  86                 return str;
  87         }
  88
  89         blockId = &(itemPtr->ip_blkid);
  90
  91         blockNumber = BlockIdGetBlockNumber(blockId);
  92         offsetNumber = itemPtr->ip_posid;
  93
  94         sprintf(buf, "(%d,%d)", blockNumber, offsetNumber);
  95
  96         str = (char *) palloc(strlen(buf) + 1);
  97         strcpy(str, buf);
  98
  99         return str;
 100 }
 101
 102 /*****************************************************************************
 103  *       PUBLIC ROUTINES                                                                                                                 *
 104  *****************************************************************************/
 105
 106 bool
 107 tideq(ItemPointer arg1, ItemPointer arg2)
 108 {
 109         if ((!arg1) || (!arg2))
 110                 return false;
 111
 112         return (BlockIdGetBlockNumber(&(arg1->ip_blkid)) ==
 113                         BlockIdGetBlockNumber(&(arg2->ip_blkid)) &&
 114                         arg1->ip_posid == arg2->ip_posid);
 115 }
 116
 117 bool
 118 tidne(ItemPointer arg1, ItemPointer arg2)
 119 {
 120         if ((!arg1) || (!arg2))
 121                 return false;
 122         return (BlockIdGetBlockNumber(&(arg1->ip_blkid)) !=
 123                         BlockIdGetBlockNumber(&(arg2->ip_blkid)) ||
 124                         arg1->ip_posid != arg2->ip_posid);
 125 }
 126
 127 text *
 128 tid_text(ItemPointer tid)
 129 {
 130         char       *str;
 131
 132         if (!tid)
 133                 return (text *) NULL;
 134         str = tidout(tid);
 135
 136         return textin(str);
 137 }       /* tid_text() */
 138
 139 ItemPointer
 140 text_tid(const text *string)
 141 {
 142         ItemPointer result;
 143         char       *str;
 144
 145         if (!string)
 146                 return (ItemPointer) 0;
 147
 148         str = textout((text *) string);
 149         result = tidin(str);
 150         pfree(str);
 151
 152         return result;
 153 }       /* text_tid() */
 154
 155
 156 /*
 157  *      Functions to get latest tid of a specified tuple.
 158  *      Maybe these implementations is moved
 159  *      to another place
 160 */
 161 #include <utils/relcache.h>
 162 ItemPointer
 163 currtid_byreloid(Oid reloid, ItemPointer tid)
 164 {
 165         ItemPointer result = NULL,
 166                                 ret;
 167         Relation        rel;
 168
 169         result = (ItemPointer) palloc(sizeof(ItemPointerData));
 170         ItemPointerSetInvalid(result);
 171         if (rel = heap_open(reloid, AccessShareLock), rel)
 172         {
 173                 ret = heap_get_latest_tid(rel, SnapshotNow, tid);
 174                 if (ret)
 175                         ItemPointerCopy(ret, result);
 176                 heap_close(rel, AccessShareLock);
 177         }
 178         else
 179                 elog(ERROR, "Relation %u not found", reloid);
 180
 181         return result;
 182 }       /* currtid_byreloid() */
 183
 184 ItemPointer
 185 currtid_byrelname(const text *relname, ItemPointer tid)
 186 {
 187         ItemPointer result = NULL,
 188                                 ret;
 189         char       *str;
 190         Relation        rel;
 191
 192         if (!relname)
 193                 return result;
 194
 195         str = textout((text *) relname);
 196
 197         result = (ItemPointer) palloc(sizeof(ItemPointerData));
 198         ItemPointerSetInvalid(result);
 199         if (rel = heap_openr(str, AccessShareLock), rel)
 200         {
 201                 ret = heap_get_latest_tid(rel, SnapshotNow, tid);
 202                 if (ret)
 203                         ItemPointerCopy(ret, result);
 204                 heap_close(rel, AccessShareLock);
 205         }
 206         else
 207                 elog(ERROR, "Relation %s not found", textout((text *) relname));
 208         pfree(str);
 209
 210         return result;
 211 }       /* currtid_byrelname() */