src/backend/access/common/scankey.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * scankey.c
   4  *        scan key support code
   5  *
   6  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  *
  10  * IDENTIFICATION
  11  *        $PostgreSQL$
  12  *
  13  *-------------------------------------------------------------------------
  14  */
  15 #include "postgres.h"
  16
  17 #include "access/skey.h"
  18
  19
  20 /*
  21  * ScanKeyEntryInitialize
  22  *              Initializes a scan key entry given all the field values.
  23  *              The target procedure is specified by OID (but can be invalid
  24  *              if SK_SEARCHNULL is set).
  25  *
  26  * Note: CurrentMemoryContext at call should be as long-lived as the ScanKey
  27  * itself, because that's what will be used for any subsidiary info attached
  28  * to the ScanKey's FmgrInfo record.
  29  */
  30 void
  31 ScanKeyEntryInitialize(ScanKey entry,
  32                                            int flags,
  33                                            AttrNumber attributeNumber,
  34                                            StrategyNumber strategy,
  35                                            Oid subtype,
  36                                            RegProcedure procedure,
  37                                            Datum argument)
  38 {
  39         entry->sk_flags = flags;
  40         entry->sk_attno = attributeNumber;
  41         entry->sk_strategy = strategy;
  42         entry->sk_subtype = subtype;
  43         entry->sk_argument = argument;
  44         if (RegProcedureIsValid(procedure))
  45                 fmgr_info(procedure, &entry->sk_func);
  46         else
  47         {
  48                 Assert(flags & SK_SEARCHNULL);
  49                 MemSet(&entry->sk_func, 0, sizeof(entry->sk_func));
  50         }
  51 }
  52
  53 /*
  54  * ScanKeyInit
  55  *              Shorthand version of ScanKeyEntryInitialize: flags and subtype
  56  *              are assumed to be zero (the usual value).
  57  *
  58  * This is the recommended version for hardwired lookups in system catalogs.
  59  * It cannot handle NULL arguments, unary operators, or nondefault operators,
  60  * but we need none of those features for most hardwired lookups.
  61  *
  62  * Note: CurrentMemoryContext at call should be as long-lived as the ScanKey
  63  * itself, because that's what will be used for any subsidiary info attached
  64  * to the ScanKey's FmgrInfo record.
  65  */
  66 void
  67 ScanKeyInit(ScanKey entry,
  68                         AttrNumber attributeNumber,
  69                         StrategyNumber strategy,
  70                         RegProcedure procedure,
  71                         Datum argument)
  72 {
  73         entry->sk_flags = 0;
  74         entry->sk_attno = attributeNumber;
  75         entry->sk_strategy = strategy;
  76         entry->sk_subtype = InvalidOid;
  77         entry->sk_argument = argument;
  78         fmgr_info(procedure, &entry->sk_func);
  79 }
  80
  81 /*
  82  * ScanKeyEntryInitializeWithInfo
  83  *              Initializes a scan key entry using an already-completed FmgrInfo
  84  *              function lookup record.
  85  *
  86  * Note: CurrentMemoryContext at call should be as long-lived as the ScanKey
  87  * itself, because that's what will be used for any subsidiary info attached
  88  * to the ScanKey's FmgrInfo record.
  89  */
  90 void
  91 ScanKeyEntryInitializeWithInfo(ScanKey entry,
  92                                                            int flags,
  93                                                            AttrNumber attributeNumber,
  94                                                            StrategyNumber strategy,
  95                                                            Oid subtype,
  96                                                            FmgrInfo *finfo,
  97                                                            Datum argument)
  98 {
  99         entry->sk_flags = flags;
 100         entry->sk_attno = attributeNumber;
 101         entry->sk_strategy = strategy;
 102         entry->sk_subtype = subtype;
 103         entry->sk_argument = argument;
 104         fmgr_info_copy(&entry->sk_func, finfo, CurrentMemoryContext);
 105 }