granicus.if.org Git - postgresql/blob - 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) 1996-2004, PostgreSQL Global Development Group
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  *
  10  * IDENTIFICATION
  11  *        $PostgreSQL: pgsql/src/backend/catalog/pg_conversion.c,v 1.19 2004/08/29 04:12:28 momjian Exp $
  12  *
  13  *-------------------------------------------------------------------------
  14  */
  15 #include "postgres.h"
  16
  17 #include "access/heapam.h"
  18 #include "catalog/catname.h"
  19 #include "catalog/dependency.h"
  20 #include "catalog/indexing.h"
  21 #include "catalog/pg_class.h"
  22 #include "catalog/pg_conversion.h"
  23 #include "catalog/namespace.h"
  24 #include "utils/builtins.h"
  25 #include "utils/lsyscache.h"
  26 #include "utils/syscache.h"
  27 #include "utils/catcache.h"
  28 #include "mb/pg_wchar.h"
  29 #include "utils/fmgroids.h"
  30 #include "utils/acl.h"
  31 #include "miscadmin.h"
  32
  33 /*
  34  * ConversionCreate
  35  *
  36  * Add a new tuple to pg_conversion.
  37  */
  38 Oid
  39 ConversionCreate(const char *conname, Oid connamespace,
  40                                  AclId conowner,
  41                                  int32 conforencoding, int32 contoencoding,
  42                                  Oid conproc, bool def)
  43 {
  44         int                     i;
  45         Relation        rel;
  46         TupleDesc       tupDesc;
  47         HeapTuple       tup;
  48         char            nulls[Natts_pg_conversion];
  49         Datum           values[Natts_pg_conversion];
  50         NameData        cname;
  51         Oid                     oid;
  52         ObjectAddress myself,
  53                                 referenced;
  54
  55         /* sanity checks */
  56         if (!conname)
  57                 elog(ERROR, "no conversion name supplied");
  58
  59         /* make sure there is no existing conversion of same name */
  60         if (SearchSysCacheExists(CONNAMENSP,
  61                                                          PointerGetDatum(conname),
  62                                                          ObjectIdGetDatum(connamespace),
  63                                                          0, 0))
  64                 ereport(ERROR,
  65                                 (errcode(ERRCODE_DUPLICATE_OBJECT),
  66                                  errmsg("conversion \"%s\" already exists", conname)));
  67
  68         if (def)
  69         {
  70                 /*
  71                  * make sure there is no existing default <for encoding><to
  72                  * encoding> pair in this name space
  73                  */
  74                 if (FindDefaultConversion(connamespace,
  75                                                                   conforencoding,
  76                                                                   contoencoding))
  77                         ereport(ERROR,
  78                                         (errcode(ERRCODE_DUPLICATE_OBJECT),
  79                                  errmsg("default conversion for %s to %s already exists",
  80                                                 pg_encoding_to_char(conforencoding),
  81                                                 pg_encoding_to_char(contoencoding))));
  82         }
  83
  84         /* open pg_conversion */
  85         rel = heap_openr(ConversionRelationName, RowExclusiveLock);
  86         tupDesc = rel->rd_att;
  87
  88         /* initialize nulls and values */
  89         for (i = 0; i < Natts_pg_conversion; i++)
  90         {
  91                 nulls[i] = ' ';
  92                 values[i] = (Datum) NULL;
  93         }
  94
  95         /* form a tuple */
  96         namestrcpy(&cname, conname);
  97         values[Anum_pg_conversion_conname - 1] = NameGetDatum(&cname);
  98         values[Anum_pg_conversion_connamespace - 1] = ObjectIdGetDatum(connamespace);
  99         values[Anum_pg_conversion_conowner - 1] = Int32GetDatum(conowner);
 100         values[Anum_pg_conversion_conforencoding - 1] = Int32GetDatum(conforencoding);
 101         values[Anum_pg_conversion_contoencoding - 1] = Int32GetDatum(contoencoding);
 102         values[Anum_pg_conversion_conproc - 1] = ObjectIdGetDatum(conproc);
 103         values[Anum_pg_conversion_condefault - 1] = BoolGetDatum(def);
 104
 105         tup = heap_formtuple(tupDesc, values, nulls);
 106
 107         /* insert a new tuple */
 108         oid = simple_heap_insert(rel, tup);
 109         Assert(OidIsValid(oid));
 110
 111         /* update the index if any */
 112         CatalogUpdateIndexes(rel, tup);
 113
 114         myself.classId = RelationGetRelid(rel);
 115         myself.objectId = HeapTupleGetOid(tup);
 116         myself.objectSubId = 0;
 117
 118         /* create dependency on conversion procedure */
 119         referenced.classId = RelOid_pg_proc;
 120         referenced.objectId = conproc;
 121         referenced.objectSubId = 0;
 122         recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
 123
 124         heap_freetuple(tup);
 125         heap_close(rel, RowExclusiveLock);
 126
 127         return oid;
 128 }
 129
 130 /*
 131  * ConversionDrop
 132  *
 133  * Drop a conversion after doing permission checks.
 134  */
 135 void
 136 ConversionDrop(Oid conversionOid, DropBehavior behavior)
 137 {
 138         HeapTuple       tuple;
 139         ObjectAddress object;
 140
 141         tuple = SearchSysCache(CONOID,
 142                                                    ObjectIdGetDatum(conversionOid),
 143                                                    0, 0, 0);
 144         if (!HeapTupleIsValid(tuple))
 145                 elog(ERROR, "cache lookup failed for conversion %u", conversionOid);
 146
 147         if (!superuser() &&
 148                 ((Form_pg_conversion) GETSTRUCT(tuple))->conowner != GetUserId())
 149                 aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CONVERSION,
 150                           NameStr(((Form_pg_conversion) GETSTRUCT(tuple))->conname));
 151
 152         ReleaseSysCache(tuple);
 153
 154         /*
 155          * Do the deletion
 156          */
 157         object.classId = get_system_catalog_relid(ConversionRelationName);
 158         object.objectId = conversionOid;
 159         object.objectSubId = 0;
 160
 161         performDeletion(&object, behavior);
 162 }
 163
 164 /*
 165  * RemoveConversionById
 166  *
 167  * Remove a tuple from pg_conversion by Oid. This function is solely
 168  * called inside catalog/dependency.c
 169  */
 170 void
 171 RemoveConversionById(Oid conversionOid)
 172 {
 173         Relation        rel;
 174         TupleDesc       tupDesc;
 175         HeapTuple       tuple;
 176         HeapScanDesc scan;
 177         ScanKeyData scanKeyData;
 178
 179         ScanKeyInit(&scanKeyData,
 180                                 ObjectIdAttributeNumber,
 181                                 BTEqualStrategyNumber, F_OIDEQ,
 182                                 ObjectIdGetDatum(conversionOid));
 183
 184         /* open pg_conversion */
 185         rel = heap_openr(ConversionRelationName, RowExclusiveLock);
 186         tupDesc = rel->rd_att;
 187
 188         scan = heap_beginscan(rel, SnapshotNow,
 189                                                   1, &scanKeyData);
 190
 191         /* search for the target tuple */
 192         if (HeapTupleIsValid(tuple = heap_getnext(scan, ForwardScanDirection)))
 193                 simple_heap_delete(rel, &tuple->t_self);
 194         else
 195                 elog(ERROR, "could not find tuple for conversion %u", conversionOid);
 196         heap_endscan(scan);
 197         heap_close(rel, RowExclusiveLock);
 198 }
 199
 200 /*
 201  * FindDefaultConversion
 202  *
 203  * Find "default" conversion proc by for_encoding and to_encoding in the
 204  * given namespace.
 205  *
 206  * If found, returns the procedure's oid, otherwise InvalidOid.  Note that
 207  * you get the procedure's OID not the conversion's OID!
 208  */
 209 Oid
 210 FindDefaultConversion(Oid name_space, int32 for_encoding, int32 to_encoding)
 211 {
 212         CatCList   *catlist;
 213         HeapTuple       tuple;
 214         Form_pg_conversion body;
 215         Oid                     proc = InvalidOid;
 216         int                     i;
 217
 218         catlist = SearchSysCacheList(CONDEFAULT, 3,
 219                                                                  ObjectIdGetDatum(name_space),
 220                                                                  Int32GetDatum(for_encoding),
 221                                                                  Int32GetDatum(to_encoding),
 222                                                                  0);
 223
 224         for (i = 0; i < catlist->n_members; i++)
 225         {
 226                 tuple = &catlist->members[i]->tuple;
 227                 body = (Form_pg_conversion) GETSTRUCT(tuple);
 228                 if (body->condefault)
 229                 {
 230                         proc = body->conproc;
 231                         break;
 232                 }
 233         }
 234         ReleaseSysCacheList(catlist);
 235         return proc;
 236 }
 237
 238 /*
 239  * FindConversion
 240  *
 241  * Find conversion by namespace and conversion name.
 242  * Returns conversion OID.
 243  */
 244 Oid
 245 FindConversion(const char *conname, Oid connamespace)
 246 {
 247         HeapTuple       tuple;
 248         Oid                     procoid;
 249         Oid                     conoid;
 250         AclResult       aclresult;
 251
 252         /* search pg_conversion by connamespace and conversion name */
 253         tuple = SearchSysCache(CONNAMENSP,
 254                                                    PointerGetDatum(conname),
 255                                                    ObjectIdGetDatum(connamespace),
 256                                                    0, 0);
 257         if (!HeapTupleIsValid(tuple))
 258                 return InvalidOid;
 259
 260         procoid = ((Form_pg_conversion) GETSTRUCT(tuple))->conproc;
 261         conoid = HeapTupleGetOid(tuple);
 262
 263         ReleaseSysCache(tuple);
 264
 265         /* Check we have execute rights for the function */
 266         aclresult = pg_proc_aclcheck(procoid, GetUserId(), ACL_EXECUTE);
 267         if (aclresult != ACLCHECK_OK)
 268                 return InvalidOid;
 269
 270         return conoid;
 271 }
 272
 273 /*
 274  * Execute SQL99's CONVERT function.
 275  *
 276  * CONVERT <left paren> <character value expression>
 277  * USING <form-of-use conversion name> <right paren>
 278  *
 279  * TEXT convert_using(TEXT string, TEXT conversion_name)
 280  */
 281 Datum
 282 pg_convert_using(PG_FUNCTION_ARGS)
 283 {
 284         text       *string = PG_GETARG_TEXT_P(0);
 285         text       *conv_name = PG_GETARG_TEXT_P(1);
 286         text       *retval;
 287         List       *parsed_name;
 288         Oid                     convoid;
 289         HeapTuple       tuple;
 290         Form_pg_conversion body;
 291         unsigned char *str;
 292         unsigned char *result;
 293         int                     len;
 294
 295         /* Convert input string to null-terminated form */
 296         len = VARSIZE(string) - VARHDRSZ;
 297         str = palloc(len + 1);
 298         memcpy(str, VARDATA(string), len);
 299         *(str + len) = '\0';
 300
 301         /* Look up the conversion name */
 302         parsed_name = textToQualifiedNameList(conv_name, "convert_using");
 303         convoid = FindConversionByName(parsed_name);
 304         if (!OidIsValid(convoid))
 305                 ereport(ERROR,
 306                                 (errcode(ERRCODE_UNDEFINED_OBJECT),
 307                                  errmsg("conversion \"%s\" does not exist",
 308                                                 NameListToString(parsed_name))));
 309
 310         tuple = SearchSysCache(CONOID,
 311                                                    ObjectIdGetDatum(convoid),
 312                                                    0, 0, 0);
 313         if (!HeapTupleIsValid(tuple))
 314                 elog(ERROR, "cache lookup failed for conversion %u", convoid);
 315         body = (Form_pg_conversion) GETSTRUCT(tuple);
 316
 317         /* Temporary result area should be more than big enough */
 318         result = palloc(len * 4 + 1);
 319
 320         OidFunctionCall5(body->conproc,
 321                                          Int32GetDatum(body->conforencoding),
 322                                          Int32GetDatum(body->contoencoding),
 323                                          CStringGetDatum(str),
 324                                          CStringGetDatum(result),
 325                                          Int32GetDatum(len));
 326
 327         ReleaseSysCache(tuple);
 328
 329         /*
 330          * build text result structure. we cannot use textin() here, since
 331          * textin assumes that input string encoding is same as database
 332          * encoding.
 333          */
 334         len = strlen(result) + VARHDRSZ;
 335         retval = palloc(len);
 336         VARATT_SIZEP(retval) = len;
 337         memcpy(VARDATA(retval), result, len - VARHDRSZ);
 338
 339         pfree(result);
 340         pfree(str);
 341
 342         PG_RETURN_TEXT_P(retval);
 343 }