src/backend/access/common/scankey.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * scankey.c
   4  *        scan key support code
   5  *
   6  * Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  *
  10  * IDENTIFICATION
  11  *        src/backend/access/common/scankey.c
  12  *
  13  *-------------------------------------------------------------------------
  14  */
  15 #include "postgres.h"
  16
  17 #include "access/skey.h"
  18 #include "catalog/pg_collation.h"
  19
  20
  21 /*
  22  * ScanKeyEntryInitialize
  23  *              Initializes a scan key entry given all the field values.
  24  *              The target procedure is specified by OID (but can be invalid
  25  *              if SK_SEARCHNULL or SK_SEARCHNOTNULL is set).
  26  *
  27  * Note: CurrentMemoryContext at call should be as long-lived as the ScanKey
  28  * itself, because that's what will be used for any subsidiary info attached
  29  * to the ScanKey's FmgrInfo record.
  30  */
  31 void
  32 ScanKeyEntryInitialize(ScanKey entry,
  33                                            int flags,
  34                                            AttrNumber attributeNumber,
  35                                            StrategyNumber strategy,
  36                                            Oid subtype,
  37                                            Oid collation,
  38                                            RegProcedure procedure,
  39                                            Datum argument)
  40 {
  41         entry->sk_flags = flags;
  42         entry->sk_attno = attributeNumber;
  43         entry->sk_strategy = strategy;
  44         entry->sk_subtype = subtype;
  45         entry->sk_collation = collation;
  46         entry->sk_argument = argument;
  47         if (RegProcedureIsValid(procedure))
  48         {
  49                 fmgr_info(procedure, &entry->sk_func);
  50         }
  51         else
  52         {
  53                 Assert(flags & (SK_SEARCHNULL | SK_SEARCHNOTNULL));
  54                 MemSet(&entry->sk_func, 0, sizeof(entry->sk_func));
  55         }
  56 }
  57
  58 /*
  59  * ScanKeyInit
  60  *              Shorthand version of ScanKeyEntryInitialize: flags and subtype
  61  *              are assumed to be zero (the usual value), and collation is defaulted.
  62  *
  63  * This is the recommended version for hardwired lookups in system catalogs.
  64  * It cannot handle NULL arguments, unary operators, or nondefault operators,
  65  * but we need none of those features for most hardwired lookups.
  66  *
  67  * We set collation to C_COLLATION_OID always.  This is the correct value
  68  * for all collation-aware columns in system catalogs, and it will be ignored
  69  * for other column types, so it's not worth trying to be more finicky.
  70  *
  71  * Note: CurrentMemoryContext at call should be as long-lived as the ScanKey
  72  * itself, because that's what will be used for any subsidiary info attached
  73  * to the ScanKey's FmgrInfo record.
  74  */
  75 void
  76 ScanKeyInit(ScanKey entry,
  77                         AttrNumber attributeNumber,
  78                         StrategyNumber strategy,
  79                         RegProcedure procedure,
  80                         Datum argument)
  81 {
  82         entry->sk_flags = 0;
  83         entry->sk_attno = attributeNumber;
  84         entry->sk_strategy = strategy;
  85         entry->sk_subtype = InvalidOid;
  86         entry->sk_collation = C_COLLATION_OID;
  87         entry->sk_argument = argument;
  88         fmgr_info(procedure, &entry->sk_func);
  89 }
  90
  91 /*
  92  * ScanKeyEntryInitializeWithInfo
  93  *              Initializes a scan key entry using an already-completed FmgrInfo
  94  *              function lookup record.
  95  *
  96  * Note: CurrentMemoryContext at call should be as long-lived as the ScanKey
  97  * itself, because that's what will be used for any subsidiary info attached
  98  * to the ScanKey's FmgrInfo record.
  99  */
 100 void
 101 ScanKeyEntryInitializeWithInfo(ScanKey entry,
 102                                                            int flags,
 103                                                            AttrNumber attributeNumber,
 104                                                            StrategyNumber strategy,
 105                                                            Oid subtype,
 106                                                            Oid collation,
 107                                                            FmgrInfo *finfo,
 108                                                            Datum argument)
 109 {
 110         entry->sk_flags = flags;
 111         entry->sk_attno = attributeNumber;
 112         entry->sk_strategy = strategy;
 113         entry->sk_subtype = subtype;
 114         entry->sk_collation = collation;
 115         entry->sk_argument = argument;
 116         fmgr_info_copy(&entry->sk_func, finfo, CurrentMemoryContext);
 117 }