src/backend/catalog/pg_conversion.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * pg_conversion.c
   4  *        routines to support manipulation of the pg_conversion relation
   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/heapam.h"
  18 #include "access/sysattr.h"
  19 #include "catalog/dependency.h"
  20 #include "catalog/indexing.h"
  21 #include "catalog/pg_conversion.h"
  22 #include "catalog/pg_conversion_fn.h"
  23 #include "catalog/pg_namespace.h"
  24 #include "catalog/pg_proc.h"
  25 #include "mb/pg_wchar.h"
  26 #include "miscadmin.h"
  27 #include "utils/acl.h"
  28 #include "utils/builtins.h"
  29 #include "utils/fmgroids.h"
  30 #include "utils/rel.h"
  31 #include "utils/syscache.h"
  32 #include "utils/tqual.h"
  33
  34 /*
  35  * ConversionCreate
  36  *
  37  * Add a new tuple to pg_conversion.
  38  */
  39 Oid
  40 ConversionCreate(const char *conname, Oid connamespace,
  41                                  Oid conowner,
  42                                  int32 conforencoding, int32 contoencoding,
  43                                  Oid conproc, bool def)
  44 {
  45         int                     i;
  46         Relation        rel;
  47         TupleDesc       tupDesc;
  48         HeapTuple       tup;
  49         bool            nulls[Natts_pg_conversion];
  50         Datum           values[Natts_pg_conversion];
  51         NameData        cname;
  52         Oid                     oid;
  53         ObjectAddress myself,
  54                                 referenced;
  55
  56         /* sanity checks */
  57         if (!conname)
  58                 elog(ERROR, "no conversion name supplied");
  59
  60         /* make sure there is no existing conversion of same name */
  61         if (SearchSysCacheExists(CONNAMENSP,
  62                                                          PointerGetDatum(conname),
  63                                                          ObjectIdGetDatum(connamespace),
  64                                                          0, 0))
  65                 ereport(ERROR,
  66                                 (errcode(ERRCODE_DUPLICATE_OBJECT),
  67                                  errmsg("conversion \"%s\" already exists", conname)));
  68
  69         if (def)
  70         {
  71                 /*
  72                  * make sure there is no existing default <for encoding><to encoding>
  73                  * pair in this name space
  74                  */
  75                 if (FindDefaultConversion(connamespace,
  76                                                                   conforencoding,
  77                                                                   contoencoding))
  78                         ereport(ERROR,
  79                                         (errcode(ERRCODE_DUPLICATE_OBJECT),
  80                                          errmsg("default conversion for %s to %s already exists",
  81                                                         pg_encoding_to_char(conforencoding),
  82                                                         pg_encoding_to_char(contoencoding))));
  83         }
  84
  85         /* open pg_conversion */
  86         rel = heap_open(ConversionRelationId, RowExclusiveLock);
  87         tupDesc = rel->rd_att;
  88
  89         /* initialize nulls and values */
  90         for (i = 0; i < Natts_pg_conversion; i++)
  91         {
  92                 nulls[i] = false;
  93                 values[i] = (Datum) NULL;
  94         }
  95
  96         /* form a tuple */
  97         namestrcpy(&cname, conname);
  98         values[Anum_pg_conversion_conname - 1] = NameGetDatum(&cname);
  99         values[Anum_pg_conversion_connamespace - 1] = ObjectIdGetDatum(connamespace);
 100         values[Anum_pg_conversion_conowner - 1] = ObjectIdGetDatum(conowner);
 101         values[Anum_pg_conversion_conforencoding - 1] = Int32GetDatum(conforencoding);
 102         values[Anum_pg_conversion_contoencoding - 1] = Int32GetDatum(contoencoding);
 103         values[Anum_pg_conversion_conproc - 1] = ObjectIdGetDatum(conproc);
 104         values[Anum_pg_conversion_condefault - 1] = BoolGetDatum(def);
 105
 106         tup = heap_form_tuple(tupDesc, values, nulls);
 107
 108         /* insert a new tuple */
 109         oid = simple_heap_insert(rel, tup);
 110         Assert(OidIsValid(oid));
 111
 112         /* update the index if any */
 113         CatalogUpdateIndexes(rel, tup);
 114
 115         myself.classId = ConversionRelationId;
 116         myself.objectId = HeapTupleGetOid(tup);
 117         myself.objectSubId = 0;
 118
 119         /* create dependency on conversion procedure */
 120         referenced.classId = ProcedureRelationId;
 121         referenced.objectId = conproc;
 122         referenced.objectSubId = 0;
 123         recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
 124
 125         /* create dependency on namespace */
 126         referenced.classId = NamespaceRelationId;
 127         referenced.objectId = connamespace;
 128         referenced.objectSubId = 0;
 129         recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
 130
 131         /* create dependency on owner */
 132         recordDependencyOnOwner(ConversionRelationId, HeapTupleGetOid(tup),
 133                                                         conowner);
 134
 135         heap_freetuple(tup);
 136         heap_close(rel, RowExclusiveLock);
 137
 138         return oid;
 139 }
 140
 141 /*
 142  * RemoveConversionById
 143  *
 144  * Remove a tuple from pg_conversion by Oid. This function is solely
 145  * called inside catalog/dependency.c
 146  */
 147 void
 148 RemoveConversionById(Oid conversionOid)
 149 {
 150         Relation        rel;
 151         HeapTuple       tuple;
 152         HeapScanDesc scan;
 153         ScanKeyData scanKeyData;
 154
 155         ScanKeyInit(&scanKeyData,
 156                                 ObjectIdAttributeNumber,
 157                                 BTEqualStrategyNumber, F_OIDEQ,
 158                                 ObjectIdGetDatum(conversionOid));
 159
 160         /* open pg_conversion */
 161         rel = heap_open(ConversionRelationId, RowExclusiveLock);
 162
 163         scan = heap_beginscan(rel, SnapshotNow,
 164                                                   1, &scanKeyData);
 165
 166         /* search for the target tuple */
 167         if (HeapTupleIsValid(tuple = heap_getnext(scan, ForwardScanDirection)))
 168                 simple_heap_delete(rel, &tuple->t_self);
 169         else
 170                 elog(ERROR, "could not find tuple for conversion %u", conversionOid);
 171         heap_endscan(scan);
 172         heap_close(rel, RowExclusiveLock);
 173 }
 174
 175 /*
 176  * FindDefaultConversion
 177  *
 178  * Find "default" conversion proc by for_encoding and to_encoding in the
 179  * given namespace.
 180  *
 181  * If found, returns the procedure's oid, otherwise InvalidOid.  Note that
 182  * you get the procedure's OID not the conversion's OID!
 183  */
 184 Oid
 185 FindDefaultConversion(Oid name_space, int32 for_encoding, int32 to_encoding)
 186 {
 187         CatCList   *catlist;
 188         HeapTuple       tuple;
 189         Form_pg_conversion body;
 190         Oid                     proc = InvalidOid;
 191         int                     i;
 192
 193         catlist = SearchSysCacheList(CONDEFAULT, 3,
 194                                                                  ObjectIdGetDatum(name_space),
 195                                                                  Int32GetDatum(for_encoding),
 196                                                                  Int32GetDatum(to_encoding),
 197                                                                  0);
 198
 199         for (i = 0; i < catlist->n_members; i++)
 200         {
 201                 tuple = &catlist->members[i]->tuple;
 202                 body = (Form_pg_conversion) GETSTRUCT(tuple);
 203                 if (body->condefault)
 204                 {
 205                         proc = body->conproc;
 206                         break;
 207                 }
 208         }
 209         ReleaseSysCacheList(catlist);
 210         return proc;
 211 }
 212
 213 /*
 214  * FindConversion
 215  *
 216  * Find conversion by namespace and conversion name.
 217  * Returns conversion OID.
 218  */
 219 Oid
 220 FindConversion(const char *conname, Oid connamespace)
 221 {
 222         HeapTuple       tuple;
 223         Oid                     procoid;
 224         Oid                     conoid;
 225         AclResult       aclresult;
 226
 227         /* search pg_conversion by connamespace and conversion name */
 228         tuple = SearchSysCache(CONNAMENSP,
 229                                                    PointerGetDatum(conname),
 230                                                    ObjectIdGetDatum(connamespace),
 231                                                    0, 0);
 232         if (!HeapTupleIsValid(tuple))
 233                 return InvalidOid;
 234
 235         procoid = ((Form_pg_conversion) GETSTRUCT(tuple))->conproc;
 236         conoid = HeapTupleGetOid(tuple);
 237
 238         ReleaseSysCache(tuple);
 239
 240         /* Check we have execute rights for the function */
 241         aclresult = pg_proc_aclcheck(procoid, GetUserId(), ACL_EXECUTE);
 242         if (aclresult != ACLCHECK_OK)
 243                 return InvalidOid;
 244
 245         return conoid;
 246 }