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  * Copyright (c) 1994, Regents of the University of California
   7  *
   8  *
   9  * IDENTIFICATION
  10  *        $Header: /cvsroot/pgsql/src/backend/utils/adt/tid.c,v 1.14 2000/01/15 02:59:38 petere Exp $
  11  *
  12  * NOTES
  13  *        input routine largely stolen from boxin().
  14  *
  15  *-------------------------------------------------------------------------
  16  */
  17
  18 #include "postgres.h"
  19 #include "utils/builtins.h"
  20
  21 #define LDELIM                  '('
  22 #define RDELIM                  ')'
  23 #define DELIM                   ','
  24 #define NTIDARGS                2
  25
  26 /* ----------------------------------------------------------------
  27  *              tidin
  28  * ----------------------------------------------------------------
  29  */
  30 ItemPointer
  31 tidin(const char *str)
  32 {
  33         const   char       *p,
  34                            *coord[NTIDARGS];
  35         int                     i;
  36         ItemPointer result;
  37
  38         BlockNumber blockNumber;
  39         OffsetNumber offsetNumber;
  40
  41         if (str == NULL)
  42                 return NULL;
  43
  44         for (i = 0, p = str; *p && i < NTIDARGS && *p != RDELIM; p++)
  45                 if (*p == DELIM || (*p == LDELIM && !i))
  46                         coord[i++] = p + 1;
  47
  48         /* if (i < NTIDARGS - 1) */
  49         if (i < NTIDARGS)
  50         {
  51                 elog(ERROR, "%s invalid tid format", str);
  52                 return NULL;
  53         }
  54
  55         blockNumber = (BlockNumber) atoi(coord[0]);
  56         offsetNumber = (OffsetNumber) atoi(coord[1]);
  57
  58         result = (ItemPointer) palloc(sizeof(ItemPointerData));
  59
  60         ItemPointerSet(result, blockNumber, offsetNumber);
  61
  62         return result;
  63 }
  64
  65 /* ----------------------------------------------------------------
  66  *              tidout
  67  * ----------------------------------------------------------------
  68  */
  69 char *
  70 tidout(ItemPointer itemPtr)
  71 {
  72         BlockNumber blockNumber;
  73         OffsetNumber offsetNumber;
  74         BlockId         blockId;
  75         char            buf[32];
  76         char       *str;
  77         static char *invalidTid = "()";
  78
  79         if (!itemPtr || !ItemPointerIsValid(itemPtr))
  80         {
  81                 str = palloc(strlen(invalidTid));
  82                 strcpy(str, invalidTid);
  83                 return str;
  84         }
  85
  86         blockId = &(itemPtr->ip_blkid);
  87
  88         blockNumber = BlockIdGetBlockNumber(blockId);
  89         offsetNumber = itemPtr->ip_posid;
  90
  91         sprintf(buf, "(%d,%d)", blockNumber, offsetNumber);
  92
  93         str = (char *) palloc(strlen(buf) + 1);
  94         strcpy(str, buf);
  95
  96         return str;
  97 }
  98
  99 /*****************************************************************************
 100  *       PUBLIC ROUTINES                                                                                                                 *
 101  *****************************************************************************/
 102
 103 bool
 104 tideq(ItemPointer arg1, ItemPointer arg2)
 105 {
 106         if ((!arg1) || (!arg2))
 107         {
 108                 return false;
 109         }
 110
 111         return ( BlockIdGetBlockNumber(&(arg1->ip_blkid)) ==
 112                  BlockIdGetBlockNumber(&(arg2->ip_blkid)) &&
 113                  arg1->ip_posid == arg2->ip_posid );
 114 }
 115
 116 bool
 117 tidne(ItemPointer arg1, ItemPointer arg2)
 118 {
 119         if ((!arg1) || (!arg2))
 120         {
 121                 return false;
 122         }
 123         return ( BlockIdGetBlockNumber(&(arg1->ip_blkid)) !=
 124                  BlockIdGetBlockNumber(&(arg2->ip_blkid)) ||
 125                  arg1->ip_posid != arg2->ip_posid );
 126 }
 127
 128 text *
 129 tid_text(ItemPointer tid)
 130 {
 131         char       *str;
 132
 133         if (!tid)       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)    return (ItemPointer)0;
 146
 147         str = textout((text *) string);
 148         result = tidin(str);
 149         pfree(str);
 150
 151         return result;
 152 }       /* text_tid() */
 153
 154
 155 /*
 156  *      Functions to get latest tid of a specified tuple.
 157  *      Maybe these implementations is moved
 158  *      to another place
 159 */
 160 #include <utils/relcache.h>
 161 ItemPointer
 162 currtid_byreloid(Oid reloid, ItemPointer tid)
 163 {
 164         ItemPointer     result = NULL, ret;
 165         Relation        rel;
 166
 167         result = (ItemPointer) palloc(sizeof(ItemPointerData));
 168         ItemPointerSetInvalid(result);
 169         if (rel = heap_open(reloid, AccessShareLock), rel)
 170         {
 171                 ret = heap_get_latest_tid(rel, SnapshotNow, tid);
 172                 if (ret)
 173                         ItemPointerCopy(ret, result);
 174                 heap_close(rel, AccessShareLock);
 175         }
 176         else
 177                 elog(ERROR, "Relation %u not found", reloid);
 178
 179         return result;
 180 }       /* currtid_byreloid() */
 181
 182 ItemPointer
 183 currtid_byrelname(const text *relname, ItemPointer tid)
 184 {
 185         ItemPointer     result = NULL, ret;
 186         char            *str;
 187         Relation        rel;
 188
 189         if (!relname)   return result;
 190
 191         str = textout((text *) relname);
 192
 193         result = (ItemPointer) palloc(sizeof(ItemPointerData));
 194         ItemPointerSetInvalid(result);
 195         if (rel = heap_openr(str, AccessShareLock), rel)
 196         {
 197                 ret = heap_get_latest_tid(rel, SnapshotNow, tid);
 198                 if (ret)
 199                         ItemPointerCopy(ret, result);
 200                 heap_close(rel, AccessShareLock);
 201         }
 202         else
 203                 elog(ERROR, "Relation %s not found", textout((text *)relname));
 204         pfree(str);
 205
 206         return result;
 207 }       /* currtid_byrelname() */