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 1.19 2000/06/08 22:37:28 momjian 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 #ifdef NOT_USED
 118 bool
 119 tidne(ItemPointer arg1, ItemPointer arg2)
 120 {
 121         if ((!arg1) || (!arg2))
 122                 return false;
 123         return (BlockIdGetBlockNumber(&(arg1->ip_blkid)) !=
 124                         BlockIdGetBlockNumber(&(arg2->ip_blkid)) ||
 125                         arg1->ip_posid != arg2->ip_posid);
 126 }
 127 #endif
 128
 129 #ifdef NOT_USED
 130 text *
 131 tid_text(ItemPointer tid)
 132 {
 133         char       *str;
 134
 135         if (!tid)
 136                 return (text *) NULL;
 137         str = tidout(tid);
 138
 139         return textin(str);
 140 }       /* tid_text() */
 141 #endif
 142
 143 #ifdef NOT_USED
 144 ItemPointer
 145 text_tid(const text *string)
 146 {
 147         ItemPointer result;
 148         char       *str;
 149
 150         if (!string)
 151                 return (ItemPointer) 0;
 152
 153         str = textout((text *) string);
 154         result = tidin(str);
 155         pfree(str);
 156
 157         return result;
 158 }       /* text_tid() */
 159 #endif
 160
 161 /*
 162  *      Functions to get latest tid of a specified tuple.
 163  *      Maybe these implementations is moved
 164  *      to another place
 165 */
 166 ItemPointer
 167 currtid_byreloid(Oid reloid, ItemPointer tid)
 168 {
 169         ItemPointer result = NULL,
 170                                 ret;
 171         Relation        rel;
 172
 173         result = (ItemPointer) palloc(sizeof(ItemPointerData));
 174         ItemPointerSetInvalid(result);
 175         if (rel = heap_open(reloid, AccessShareLock), rel)
 176         {
 177                 ret = heap_get_latest_tid(rel, SnapshotNow, tid);
 178                 if (ret)
 179                         ItemPointerCopy(ret, result);
 180                 heap_close(rel, AccessShareLock);
 181         }
 182         else
 183                 elog(ERROR, "Relation %u not found", reloid);
 184
 185         return result;
 186 }       /* currtid_byreloid() */
 187
 188 ItemPointer
 189 currtid_byrelname(const text *relname, ItemPointer tid)
 190 {
 191         ItemPointer result = NULL,
 192                                 ret;
 193         char       *str;
 194         Relation        rel;
 195
 196         if (!relname)
 197                 return result;
 198
 199         str = textout((text *) relname);
 200
 201         result = (ItemPointer) palloc(sizeof(ItemPointerData));
 202         ItemPointerSetInvalid(result);
 203         if (rel = heap_openr(str, AccessShareLock), rel)
 204         {
 205                 ret = heap_get_latest_tid(rel, SnapshotNow, tid);
 206                 if (ret)
 207                         ItemPointerCopy(ret, result);
 208                 heap_close(rel, AccessShareLock);
 209         }
 210         else
 211                 elog(ERROR, "Relation %s not found", textout((text *) relname));
 212         pfree(str);
 213
 214         return result;
 215 }       /* currtid_byrelname() */