src/backend/catalog/pg_cast.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * pg_cast.c
   4  *        routines to support manipulation of the pg_cast relation
   5  *
   6  * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  *
  10  * IDENTIFICATION
  11  *        src/backend/catalog/pg_cast.c
  12  *
  13  *-------------------------------------------------------------------------
  14  */
  15 #include "postgres.h"
  16
  17 #include "access/htup_details.h"
  18 #include "access/table.h"
  19 #include "catalog/catalog.h"
  20 #include "catalog/dependency.h"
  21 #include "catalog/indexing.h"
  22 #include "catalog/objectaccess.h"
  23 #include "catalog/pg_cast.h"
  24 #include "catalog/pg_proc.h"
  25 #include "catalog/pg_type.h"
  26 #include "utils/builtins.h"
  27 #include "utils/rel.h"
  28 #include "utils/syscache.h"
  29
  30 /*
  31  * ----------------------------------------------------------------
  32  *              CastCreate
  33  *
  34  * Forms and inserts catalog tuples for a new cast being created.
  35  * Caller must have already checked privileges, and done consistency
  36  * checks on the given datatypes and cast function (if applicable).
  37  *
  38  * 'behavior' indicates the types of the dependencies that the new
  39  * cast will have on its input and output types and the cast function.
  40  * ----------------------------------------------------------------
  41  */
  42 ObjectAddress
  43 CastCreate(Oid sourcetypeid, Oid targettypeid, Oid funcid, char castcontext,
  44                    char castmethod, DependencyType behavior)
  45 {
  46         Relation        relation;
  47         HeapTuple       tuple;
  48         Oid                     castid;
  49         Datum           values[Natts_pg_cast];
  50         bool            nulls[Natts_pg_cast];
  51         ObjectAddress myself,
  52                                 referenced;
  53
  54         relation = table_open(CastRelationId, RowExclusiveLock);
  55
  56         /*
  57          * Check for duplicate.  This is just to give a friendly error message,
  58          * the unique index would catch it anyway (so no need to sweat about race
  59          * conditions).
  60          */
  61         tuple = SearchSysCache2(CASTSOURCETARGET,
  62                                                         ObjectIdGetDatum(sourcetypeid),
  63                                                         ObjectIdGetDatum(targettypeid));
  64         if (HeapTupleIsValid(tuple))
  65                 ereport(ERROR,
  66                                 (errcode(ERRCODE_DUPLICATE_OBJECT),
  67                                  errmsg("cast from type %s to type %s already exists",
  68                                                 format_type_be(sourcetypeid),
  69                                                 format_type_be(targettypeid))));
  70
  71         /* ready to go */
  72         castid = GetNewOidWithIndex(relation, CastOidIndexId, Anum_pg_cast_oid);
  73         values[Anum_pg_cast_oid - 1] = ObjectIdGetDatum(castid);
  74         values[Anum_pg_cast_castsource - 1] = ObjectIdGetDatum(sourcetypeid);
  75         values[Anum_pg_cast_casttarget - 1] = ObjectIdGetDatum(targettypeid);
  76         values[Anum_pg_cast_castfunc - 1] = ObjectIdGetDatum(funcid);
  77         values[Anum_pg_cast_castcontext - 1] = CharGetDatum(castcontext);
  78         values[Anum_pg_cast_castmethod - 1] = CharGetDatum(castmethod);
  79
  80         MemSet(nulls, false, sizeof(nulls));
  81
  82         tuple = heap_form_tuple(RelationGetDescr(relation), values, nulls);
  83
  84         CatalogTupleInsert(relation, tuple);
  85
  86         /* make dependency entries */
  87         myself.classId = CastRelationId;
  88         myself.objectId = castid;
  89         myself.objectSubId = 0;
  90
  91         /* dependency on source type */
  92         referenced.classId = TypeRelationId;
  93         referenced.objectId = sourcetypeid;
  94         referenced.objectSubId = 0;
  95         recordDependencyOn(&myself, &referenced, behavior);
  96
  97         /* dependency on target type */
  98         referenced.classId = TypeRelationId;
  99         referenced.objectId = targettypeid;
 100         referenced.objectSubId = 0;
 101         recordDependencyOn(&myself, &referenced, behavior);
 102
 103         /* dependency on function */
 104         if (OidIsValid(funcid))
 105         {
 106                 referenced.classId = ProcedureRelationId;
 107                 referenced.objectId = funcid;
 108                 referenced.objectSubId = 0;
 109                 recordDependencyOn(&myself, &referenced, behavior);
 110         }
 111
 112         /* dependency on extension */
 113         recordDependencyOnCurrentExtension(&myself, false);
 114
 115         /* Post creation hook for new cast */
 116         InvokeObjectPostCreateHook(CastRelationId, castid, 0);
 117
 118         heap_freetuple(tuple);
 119
 120         table_close(relation, RowExclusiveLock);
 121
 122         return myself;
 123 }