granicus.if.org Git - postgresql/blob - src/backend/utils/fmgr/funcapi.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * funcapi.c
   4  *        Utility and convenience functions for fmgr functions that return
   5  *        sets and/or composite types.
   6  *
   7  * Copyright (c) 2002-2012, PostgreSQL Global Development Group
   8  *
   9  * IDENTIFICATION
  10  *        src/backend/utils/fmgr/funcapi.c
  11  *
  12  *-------------------------------------------------------------------------
  13  */
  14 #include "postgres.h"
  15
  16 #include "catalog/namespace.h"
  17 #include "catalog/pg_proc.h"
  18 #include "catalog/pg_type.h"
  19 #include "funcapi.h"
  20 #include "nodes/nodeFuncs.h"
  21 #include "parser/parse_coerce.h"
  22 #include "utils/array.h"
  23 #include "utils/builtins.h"
  24 #include "utils/lsyscache.h"
  25 #include "utils/memutils.h"
  26 #include "utils/rel.h"
  27 #include "utils/syscache.h"
  28 #include "utils/typcache.h"
  29
  30
  31 static void shutdown_MultiFuncCall(Datum arg);
  32 static TypeFuncClass internal_get_result_type(Oid funcid,
  33                                                  Node *call_expr,
  34                                                  ReturnSetInfo *rsinfo,
  35                                                  Oid *resultTypeId,
  36                                                  TupleDesc *resultTupleDesc);
  37 static bool resolve_polymorphic_tupdesc(TupleDesc tupdesc,
  38                                                         oidvector *declared_args,
  39                                                         Node *call_expr);
  40 static TypeFuncClass get_type_func_class(Oid typid);
  41
  42
  43 /*
  44  * init_MultiFuncCall
  45  * Create an empty FuncCallContext data structure
  46  * and do some other basic Multi-function call setup
  47  * and error checking
  48  */
  49 FuncCallContext *
  50 init_MultiFuncCall(PG_FUNCTION_ARGS)
  51 {
  52         FuncCallContext *retval;
  53
  54         /*
  55          * Bail if we're called in the wrong context
  56          */
  57         if (fcinfo->resultinfo == NULL || !IsA(fcinfo->resultinfo, ReturnSetInfo))
  58                 ereport(ERROR,
  59                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
  60                                  errmsg("set-valued function called in context that cannot accept a set")));
  61
  62         if (fcinfo->flinfo->fn_extra == NULL)
  63         {
  64                 /*
  65                  * First call
  66                  */
  67                 ReturnSetInfo *rsi = (ReturnSetInfo *) fcinfo->resultinfo;
  68                 MemoryContext multi_call_ctx;
  69
  70                 /*
  71                  * Create a suitably long-lived context to hold cross-call data
  72                  */
  73                 multi_call_ctx = AllocSetContextCreate(fcinfo->flinfo->fn_mcxt,
  74                                                                                            "SRF multi-call context",
  75                                                                                            ALLOCSET_SMALL_MINSIZE,
  76                                                                                            ALLOCSET_SMALL_INITSIZE,
  77                                                                                            ALLOCSET_SMALL_MAXSIZE);
  78
  79                 /*
  80                  * Allocate suitably long-lived space and zero it
  81                  */
  82                 retval = (FuncCallContext *)
  83                         MemoryContextAllocZero(multi_call_ctx,
  84                                                                    sizeof(FuncCallContext));
  85
  86                 /*
  87                  * initialize the elements
  88                  */
  89                 retval->call_cntr = 0;
  90                 retval->max_calls = 0;
  91                 retval->slot = NULL;
  92                 retval->user_fctx = NULL;
  93                 retval->attinmeta = NULL;
  94                 retval->tuple_desc = NULL;
  95                 retval->multi_call_memory_ctx = multi_call_ctx;
  96
  97                 /*
  98                  * save the pointer for cross-call use
  99                  */
 100                 fcinfo->flinfo->fn_extra = retval;
 101
 102                 /*
 103                  * Ensure we will get shut down cleanly if the exprcontext is not run
 104                  * to completion.
 105                  */
 106                 RegisterExprContextCallback(rsi->econtext,
 107                                                                         shutdown_MultiFuncCall,
 108                                                                         PointerGetDatum(fcinfo->flinfo));
 109         }
 110         else
 111         {
 112                 /* second and subsequent calls */
 113                 elog(ERROR, "init_MultiFuncCall cannot be called more than once");
 114
 115                 /* never reached, but keep compiler happy */
 116                 retval = NULL;
 117         }
 118
 119         return retval;
 120 }
 121
 122 /*
 123  * per_MultiFuncCall
 124  *
 125  * Do Multi-function per-call setup
 126  */
 127 FuncCallContext *
 128 per_MultiFuncCall(PG_FUNCTION_ARGS)
 129 {
 130         FuncCallContext *retval = (FuncCallContext *) fcinfo->flinfo->fn_extra;
 131
 132         /*
 133          * Clear the TupleTableSlot, if present.  This is for safety's sake: the
 134          * Slot will be in a long-lived context (it better be, if the
 135          * FuncCallContext is pointing to it), but in most usage patterns the
 136          * tuples stored in it will be in the function's per-tuple context. So at
 137          * the beginning of each call, the Slot will hold a dangling pointer to an
 138          * already-recycled tuple.      We clear it out here.
 139          *
 140          * Note: use of retval->slot is obsolete as of 8.0, and we expect that it
 141          * will always be NULL.  This is just here for backwards compatibility in
 142          * case someone creates a slot anyway.
 143          */
 144         if (retval->slot != NULL)
 145                 ExecClearTuple(retval->slot);
 146
 147         return retval;
 148 }
 149
 150 /*
 151  * end_MultiFuncCall
 152  * Clean up after init_MultiFuncCall
 153  */
 154 void
 155 end_MultiFuncCall(PG_FUNCTION_ARGS, FuncCallContext *funcctx)
 156 {
 157         ReturnSetInfo *rsi = (ReturnSetInfo *) fcinfo->resultinfo;
 158
 159         /* Deregister the shutdown callback */
 160         UnregisterExprContextCallback(rsi->econtext,
 161                                                                   shutdown_MultiFuncCall,
 162                                                                   PointerGetDatum(fcinfo->flinfo));
 163
 164         /* But use it to do the real work */
 165         shutdown_MultiFuncCall(PointerGetDatum(fcinfo->flinfo));
 166 }
 167
 168 /*
 169  * shutdown_MultiFuncCall
 170  * Shutdown function to clean up after init_MultiFuncCall
 171  */
 172 static void
 173 shutdown_MultiFuncCall(Datum arg)
 174 {
 175         FmgrInfo   *flinfo = (FmgrInfo *) DatumGetPointer(arg);
 176         FuncCallContext *funcctx = (FuncCallContext *) flinfo->fn_extra;
 177
 178         /* unbind from flinfo */
 179         flinfo->fn_extra = NULL;
 180
 181         /*
 182          * Delete context that holds all multi-call data, including the
 183          * FuncCallContext itself
 184          */
 185         MemoryContextDelete(funcctx->multi_call_memory_ctx);
 186 }
 187
 188
 189 /*
 190  * get_call_result_type
 191  *              Given a function's call info record, determine the kind of datatype
 192  *              it is supposed to return.  If resultTypeId isn't NULL, *resultTypeId
 193  *              receives the actual datatype OID (this is mainly useful for scalar
 194  *              result types).  If resultTupleDesc isn't NULL, *resultTupleDesc
 195  *              receives a pointer to a TupleDesc when the result is of a composite
 196  *              type, or NULL when it's a scalar result.
 197  *
 198  * One hard case that this handles is resolution of actual rowtypes for
 199  * functions returning RECORD (from either the function's OUT parameter
 200  * list, or a ReturnSetInfo context node).      TYPEFUNC_RECORD is returned
 201  * only when we couldn't resolve the actual rowtype for lack of information.
 202  *
 203  * The other hard case that this handles is resolution of polymorphism.
 204  * We will never return polymorphic pseudotypes (ANYELEMENT etc), either
 205  * as a scalar result type or as a component of a rowtype.
 206  *
 207  * This function is relatively expensive --- in a function returning set,
 208  * try to call it only the first time through.
 209  */
 210 TypeFuncClass
 211 get_call_result_type(FunctionCallInfo fcinfo,
 212                                          Oid *resultTypeId,
 213                                          TupleDesc *resultTupleDesc)
 214 {
 215         return internal_get_result_type(fcinfo->flinfo->fn_oid,
 216                                                                         fcinfo->flinfo->fn_expr,
 217                                                                         (ReturnSetInfo *) fcinfo->resultinfo,
 218                                                                         resultTypeId,
 219                                                                         resultTupleDesc);
 220 }
 221
 222 /*
 223  * get_expr_result_type
 224  *              As above, but work from a calling expression node tree
 225  */
 226 TypeFuncClass
 227 get_expr_result_type(Node *expr,
 228                                          Oid *resultTypeId,
 229                                          TupleDesc *resultTupleDesc)
 230 {
 231         TypeFuncClass result;
 232
 233         if (expr && IsA(expr, FuncExpr))
 234                 result = internal_get_result_type(((FuncExpr *) expr)->funcid,
 235                                                                                   expr,
 236                                                                                   NULL,
 237                                                                                   resultTypeId,
 238                                                                                   resultTupleDesc);
 239         else if (expr && IsA(expr, OpExpr))
 240                 result = internal_get_result_type(get_opcode(((OpExpr *) expr)->opno),
 241                                                                                   expr,
 242                                                                                   NULL,
 243                                                                                   resultTypeId,
 244                                                                                   resultTupleDesc);
 245         else
 246         {
 247                 /* handle as a generic expression; no chance to resolve RECORD */
 248                 Oid                     typid = exprType(expr);
 249
 250                 if (resultTypeId)
 251                         *resultTypeId = typid;
 252                 if (resultTupleDesc)
 253                         *resultTupleDesc = NULL;
 254                 result = get_type_func_class(typid);
 255                 if (result == TYPEFUNC_COMPOSITE && resultTupleDesc)
 256                         *resultTupleDesc = lookup_rowtype_tupdesc_copy(typid, -1);
 257         }
 258
 259         return result;
 260 }
 261
 262 /*
 263  * get_func_result_type
 264  *              As above, but work from a function's OID only
 265  *
 266  * This will not be able to resolve pure-RECORD results nor polymorphism.
 267  */
 268 TypeFuncClass
 269 get_func_result_type(Oid functionId,
 270                                          Oid *resultTypeId,
 271                                          TupleDesc *resultTupleDesc)
 272 {
 273         return internal_get_result_type(functionId,
 274                                                                         NULL,
 275                                                                         NULL,
 276                                                                         resultTypeId,
 277                                                                         resultTupleDesc);
 278 }
 279
 280 /*
 281  * internal_get_result_type -- workhorse code implementing all the above
 282  *
 283  * funcid must always be supplied.      call_expr and rsinfo can be NULL if not
 284  * available.  We will return TYPEFUNC_RECORD, and store NULL into
 285  * *resultTupleDesc, if we cannot deduce the complete result rowtype from
 286  * the available information.
 287  */
 288 static TypeFuncClass
 289 internal_get_result_type(Oid funcid,
 290                                                  Node *call_expr,
 291                                                  ReturnSetInfo *rsinfo,
 292                                                  Oid *resultTypeId,
 293                                                  TupleDesc *resultTupleDesc)
 294 {
 295         TypeFuncClass result;
 296         HeapTuple       tp;
 297         Form_pg_proc procform;
 298         Oid                     rettype;
 299         TupleDesc       tupdesc;
 300
 301         /* First fetch the function's pg_proc row to inspect its rettype */
 302         tp = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
 303         if (!HeapTupleIsValid(tp))
 304                 elog(ERROR, "cache lookup failed for function %u", funcid);
 305         procform = (Form_pg_proc) GETSTRUCT(tp);
 306
 307         rettype = procform->prorettype;
 308
 309         /* Check for OUT parameters defining a RECORD result */
 310         tupdesc = build_function_result_tupdesc_t(tp);
 311         if (tupdesc)
 312         {
 313                 /*
 314                  * It has OUT parameters, so it's basically like a regular composite
 315                  * type, except we have to be able to resolve any polymorphic OUT
 316                  * parameters.
 317                  */
 318                 if (resultTypeId)
 319                         *resultTypeId = rettype;
 320
 321                 if (resolve_polymorphic_tupdesc(tupdesc,
 322                                                                                 &procform->proargtypes,
 323                                                                                 call_expr))
 324                 {
 325                         if (tupdesc->tdtypeid == RECORDOID &&
 326                                 tupdesc->tdtypmod < 0)
 327                                 assign_record_type_typmod(tupdesc);
 328                         if (resultTupleDesc)
 329                                 *resultTupleDesc = tupdesc;
 330                         result = TYPEFUNC_COMPOSITE;
 331                 }
 332                 else
 333                 {
 334                         if (resultTupleDesc)
 335                                 *resultTupleDesc = NULL;
 336                         result = TYPEFUNC_RECORD;
 337                 }
 338
 339                 ReleaseSysCache(tp);
 340
 341                 return result;
 342         }
 343
 344         /*
 345          * If scalar polymorphic result, try to resolve it.
 346          */
 347         if (IsPolymorphicType(rettype))
 348         {
 349                 Oid                     newrettype = exprType(call_expr);
 350
 351                 if (newrettype == InvalidOid)   /* this probably should not happen */
 352                         ereport(ERROR,
 353                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
 354                                          errmsg("could not determine actual result type for function \"%s\" declared to return type %s",
 355                                                         NameStr(procform->proname),
 356                                                         format_type_be(rettype))));
 357                 rettype = newrettype;
 358         }
 359
 360         if (resultTypeId)
 361                 *resultTypeId = rettype;
 362         if (resultTupleDesc)
 363                 *resultTupleDesc = NULL;        /* default result */
 364
 365         /* Classify the result type */
 366         result = get_type_func_class(rettype);
 367         switch (result)
 368         {
 369                 case TYPEFUNC_COMPOSITE:
 370                         if (resultTupleDesc)
 371                                 *resultTupleDesc = lookup_rowtype_tupdesc_copy(rettype, -1);
 372                         /* Named composite types can't have any polymorphic columns */
 373                         break;
 374                 case TYPEFUNC_SCALAR:
 375                         break;
 376                 case TYPEFUNC_RECORD:
 377                         /* We must get the tupledesc from call context */
 378                         if (rsinfo && IsA(rsinfo, ReturnSetInfo) &&
 379                                 rsinfo->expectedDesc != NULL)
 380                         {
 381                                 result = TYPEFUNC_COMPOSITE;
 382                                 if (resultTupleDesc)
 383                                         *resultTupleDesc = rsinfo->expectedDesc;
 384                                 /* Assume no polymorphic columns here, either */
 385                         }
 386                         break;
 387                 default:
 388                         break;
 389         }
 390
 391         ReleaseSysCache(tp);
 392
 393         return result;
 394 }
 395
 396 /*
 397  * Given the result tuple descriptor for a function with OUT parameters,
 398  * replace any polymorphic columns (ANYELEMENT etc) with correct data types
 399  * deduced from the input arguments. Returns TRUE if able to deduce all types,
 400  * FALSE if not.
 401  */
 402 static bool
 403 resolve_polymorphic_tupdesc(TupleDesc tupdesc, oidvector *declared_args,
 404                                                         Node *call_expr)
 405 {
 406         int                     natts = tupdesc->natts;
 407         int                     nargs = declared_args->dim1;
 408         bool            have_anyelement_result = false;
 409         bool            have_anyarray_result = false;
 410         bool            have_anyrange_result = false;
 411         bool            have_anynonarray = false;
 412         bool            have_anyenum = false;
 413         Oid                     anyelement_type = InvalidOid;
 414         Oid                     anyarray_type = InvalidOid;
 415         Oid                     anyrange_type = InvalidOid;
 416         Oid                     anycollation = InvalidOid;
 417         int                     i;
 418
 419         /* See if there are any polymorphic outputs; quick out if not */
 420         for (i = 0; i < natts; i++)
 421         {
 422                 switch (tupdesc->attrs[i]->atttypid)
 423                 {
 424                         case ANYELEMENTOID:
 425                                 have_anyelement_result = true;
 426                                 break;
 427                         case ANYARRAYOID:
 428                                 have_anyarray_result = true;
 429                                 break;
 430                         case ANYNONARRAYOID:
 431                                 have_anyelement_result = true;
 432                                 have_anynonarray = true;
 433                                 break;
 434                         case ANYENUMOID:
 435                                 have_anyelement_result = true;
 436                                 have_anyenum = true;
 437                                 break;
 438                         case ANYRANGEOID:
 439                                 have_anyrange_result = true;
 440                                 break;
 441                         default:
 442                                 break;
 443                 }
 444         }
 445         if (!have_anyelement_result && !have_anyarray_result &&
 446                 !have_anyrange_result)
 447                 return true;
 448
 449         /*
 450          * Otherwise, extract actual datatype(s) from input arguments.  (We assume
 451          * the parser already validated consistency of the arguments.)
 452          */
 453         if (!call_expr)
 454                 return false;                   /* no hope */
 455
 456         for (i = 0; i < nargs; i++)
 457         {
 458                 switch (declared_args->values[i])
 459                 {
 460                         case ANYELEMENTOID:
 461                         case ANYNONARRAYOID:
 462                         case ANYENUMOID:
 463                                 if (!OidIsValid(anyelement_type))
 464                                         anyelement_type = get_call_expr_argtype(call_expr, i);
 465                                 break;
 466                         case ANYARRAYOID:
 467                                 if (!OidIsValid(anyarray_type))
 468                                         anyarray_type = get_call_expr_argtype(call_expr, i);
 469                                 break;
 470                         case ANYRANGEOID:
 471                                 if (!OidIsValid(anyrange_type))
 472                                         anyrange_type = get_call_expr_argtype(call_expr, i);
 473                                 break;
 474                         default:
 475                                 break;
 476                 }
 477         }
 478
 479         /* If nothing found, parser messed up */
 480         if (!OidIsValid(anyelement_type) && !OidIsValid(anyarray_type) &&
 481                 !OidIsValid(anyrange_type))
 482                 return false;
 483
 484         /* If needed, deduce one polymorphic type from others */
 485         if (have_anyelement_result && !OidIsValid(anyelement_type))
 486         {
 487                 if (OidIsValid(anyarray_type))
 488                         anyelement_type = resolve_generic_type(ANYELEMENTOID,
 489                                                                                                    anyarray_type,
 490                                                                                                    ANYARRAYOID);
 491                 if (OidIsValid(anyrange_type))
 492                 {
 493                         Oid                     subtype = resolve_generic_type(ANYELEMENTOID,
 494                                                                                                            anyrange_type,
 495                                                                                                            ANYRANGEOID);
 496
 497                         /* check for inconsistent array and range results */
 498                         if (OidIsValid(anyelement_type) && anyelement_type != subtype)
 499                                 return false;
 500                         anyelement_type = subtype;
 501                 }
 502         }
 503
 504         if (have_anyarray_result && !OidIsValid(anyarray_type))
 505                 anyarray_type = resolve_generic_type(ANYARRAYOID,
 506                                                                                          anyelement_type,
 507                                                                                          ANYELEMENTOID);
 508
 509         /*
 510          * We can't deduce a range type from other polymorphic inputs, because
 511          * there may be multiple range types for the same subtype.
 512          */
 513         if (have_anyrange_result && !OidIsValid(anyrange_type))
 514                 return false;
 515
 516         /* Enforce ANYNONARRAY if needed */
 517         if (have_anynonarray && type_is_array(anyelement_type))
 518                 return false;
 519
 520         /* Enforce ANYENUM if needed */
 521         if (have_anyenum && !type_is_enum(anyelement_type))
 522                 return false;
 523
 524         /*
 525          * Identify the collation to use for polymorphic OUT parameters. (It'll
 526          * necessarily be the same for both anyelement and anyarray.)  Note that
 527          * range types are not collatable, so any possible internal collation of a
 528          * range type is not considered here.
 529          */
 530         if (OidIsValid(anyelement_type))
 531                 anycollation = get_typcollation(anyelement_type);
 532         else if (OidIsValid(anyarray_type))
 533                 anycollation = get_typcollation(anyarray_type);
 534
 535         if (OidIsValid(anycollation))
 536         {
 537                 /*
 538                  * The types are collatable, so consider whether to use a nondefault
 539                  * collation.  We do so if we can identify the input collation used
 540                  * for the function.
 541                  */
 542                 Oid                     inputcollation = exprInputCollation(call_expr);
 543
 544                 if (OidIsValid(inputcollation))
 545                         anycollation = inputcollation;
 546         }
 547
 548         /* And finally replace the tuple column types as needed */
 549         for (i = 0; i < natts; i++)
 550         {
 551                 switch (tupdesc->attrs[i]->atttypid)
 552                 {
 553                         case ANYELEMENTOID:
 554                         case ANYNONARRAYOID:
 555                         case ANYENUMOID:
 556                                 TupleDescInitEntry(tupdesc, i + 1,
 557                                                                    NameStr(tupdesc->attrs[i]->attname),
 558                                                                    anyelement_type,
 559                                                                    -1,
 560                                                                    0);
 561                                 TupleDescInitEntryCollation(tupdesc, i + 1, anycollation);
 562                                 break;
 563                         case ANYARRAYOID:
 564                                 TupleDescInitEntry(tupdesc, i + 1,
 565                                                                    NameStr(tupdesc->attrs[i]->attname),
 566                                                                    anyarray_type,
 567                                                                    -1,
 568                                                                    0);
 569                                 TupleDescInitEntryCollation(tupdesc, i + 1, anycollation);
 570                                 break;
 571                         case ANYRANGEOID:
 572                                 TupleDescInitEntry(tupdesc, i + 1,
 573                                                                    NameStr(tupdesc->attrs[i]->attname),
 574                                                                    anyrange_type,
 575                                                                    -1,
 576                                                                    0);
 577                                 /* no collation should be attached to a range type */
 578                                 break;
 579                         default:
 580                                 break;
 581                 }
 582         }
 583
 584         return true;
 585 }
 586
 587 /*
 588  * Given the declared argument types and modes for a function, replace any
 589  * polymorphic types (ANYELEMENT etc) with correct data types deduced from the
 590  * input arguments.  Returns TRUE if able to deduce all types, FALSE if not.
 591  * This is the same logic as resolve_polymorphic_tupdesc, but with a different
 592  * argument representation.
 593  *
 594  * argmodes may be NULL, in which case all arguments are assumed to be IN mode.
 595  */
 596 bool
 597 resolve_polymorphic_argtypes(int numargs, Oid *argtypes, char *argmodes,
 598                                                          Node *call_expr)
 599 {
 600         bool            have_anyelement_result = false;
 601         bool            have_anyarray_result = false;
 602         bool            have_anyrange_result = false;
 603         Oid                     anyelement_type = InvalidOid;
 604         Oid                     anyarray_type = InvalidOid;
 605         Oid                     anyrange_type = InvalidOid;
 606         int                     inargno;
 607         int                     i;
 608
 609         /* First pass: resolve polymorphic inputs, check for outputs */
 610         inargno = 0;
 611         for (i = 0; i < numargs; i++)
 612         {
 613                 char            argmode = argmodes ? argmodes[i] : PROARGMODE_IN;
 614
 615                 switch (argtypes[i])
 616                 {
 617                         case ANYELEMENTOID:
 618                         case ANYNONARRAYOID:
 619                         case ANYENUMOID:
 620                                 if (argmode == PROARGMODE_OUT || argmode == PROARGMODE_TABLE)
 621                                         have_anyelement_result = true;
 622                                 else
 623                                 {
 624                                         if (!OidIsValid(anyelement_type))
 625                                         {
 626                                                 anyelement_type = get_call_expr_argtype(call_expr,
 627                                                                                                                                 inargno);
 628                                                 if (!OidIsValid(anyelement_type))
 629                                                         return false;
 630                                         }
 631                                         argtypes[i] = anyelement_type;
 632                                 }
 633                                 break;
 634                         case ANYARRAYOID:
 635                                 if (argmode == PROARGMODE_OUT || argmode == PROARGMODE_TABLE)
 636                                         have_anyarray_result = true;
 637                                 else
 638                                 {
 639                                         if (!OidIsValid(anyarray_type))
 640                                         {
 641                                                 anyarray_type = get_call_expr_argtype(call_expr,
 642                                                                                                                           inargno);
 643                                                 if (!OidIsValid(anyarray_type))
 644                                                         return false;
 645                                         }
 646                                         argtypes[i] = anyarray_type;
 647                                 }
 648                                 break;
 649                         case ANYRANGEOID:
 650                                 if (argmode == PROARGMODE_OUT || argmode == PROARGMODE_TABLE)
 651                                         have_anyrange_result = true;
 652                                 else
 653                                 {
 654                                         if (!OidIsValid(anyrange_type))
 655                                         {
 656                                                 anyrange_type = get_call_expr_argtype(call_expr,
 657                                                                                                                           inargno);
 658                                                 if (!OidIsValid(anyrange_type))
 659                                                         return false;
 660                                         }
 661                                         argtypes[i] = anyrange_type;
 662                                 }
 663                                 break;
 664                         default:
 665                                 break;
 666                 }
 667                 if (argmode != PROARGMODE_OUT && argmode != PROARGMODE_TABLE)
 668                         inargno++;
 669         }
 670
 671         /* Done? */
 672         if (!have_anyelement_result && !have_anyarray_result &&
 673                 !have_anyrange_result)
 674                 return true;
 675
 676         /* If no input polymorphics, parser messed up */
 677         if (!OidIsValid(anyelement_type) && !OidIsValid(anyarray_type) &&
 678                 !OidIsValid(anyrange_type))
 679                 return false;
 680
 681         /* If needed, deduce one polymorphic type from others */
 682         if (have_anyelement_result && !OidIsValid(anyelement_type))
 683         {
 684                 if (OidIsValid(anyarray_type))
 685                         anyelement_type = resolve_generic_type(ANYELEMENTOID,
 686                                                                                                    anyarray_type,
 687                                                                                                    ANYARRAYOID);
 688                 if (OidIsValid(anyrange_type))
 689                 {
 690                         Oid                     subtype = resolve_generic_type(ANYELEMENTOID,
 691                                                                                                            anyrange_type,
 692                                                                                                            ANYRANGEOID);
 693
 694                         /* check for inconsistent array and range results */
 695                         if (OidIsValid(anyelement_type) && anyelement_type != subtype)
 696                                 return false;
 697                         anyelement_type = subtype;
 698                 }
 699         }
 700
 701         if (have_anyarray_result && !OidIsValid(anyarray_type))
 702                 anyarray_type = resolve_generic_type(ANYARRAYOID,
 703                                                                                          anyelement_type,
 704                                                                                          ANYELEMENTOID);
 705
 706         /*
 707          * We can't deduce a range type from other polymorphic inputs, because
 708          * there may be multiple range types for the same subtype.
 709          */
 710         if (have_anyrange_result && !OidIsValid(anyrange_type))
 711                 return false;
 712
 713         /* XXX do we need to enforce ANYNONARRAY or ANYENUM here?  I think not */
 714
 715         /* And finally replace the output column types as needed */
 716         for (i = 0; i < numargs; i++)
 717         {
 718                 switch (argtypes[i])
 719                 {
 720                         case ANYELEMENTOID:
 721                         case ANYNONARRAYOID:
 722                         case ANYENUMOID:
 723                                 argtypes[i] = anyelement_type;
 724                                 break;
 725                         case ANYARRAYOID:
 726                                 argtypes[i] = anyarray_type;
 727                                 break;
 728                         case ANYRANGEOID:
 729                                 argtypes[i] = anyrange_type;
 730                                 break;
 731                         default:
 732                                 break;
 733                 }
 734         }
 735
 736         return true;
 737 }
 738
 739 /*
 740  * get_type_func_class
 741  *              Given the type OID, obtain its TYPEFUNC classification.
 742  *
 743  * This is intended to centralize a bunch of formerly ad-hoc code for
 744  * classifying types.  The categories used here are useful for deciding
 745  * how to handle functions returning the datatype.
 746  */
 747 static TypeFuncClass
 748 get_type_func_class(Oid typid)
 749 {
 750         switch (get_typtype(typid))
 751         {
 752                 case TYPTYPE_COMPOSITE:
 753                         return TYPEFUNC_COMPOSITE;
 754                 case TYPTYPE_BASE:
 755                 case TYPTYPE_DOMAIN:
 756                 case TYPTYPE_ENUM:
 757                 case TYPTYPE_RANGE:
 758                         return TYPEFUNC_SCALAR;
 759                 case TYPTYPE_PSEUDO:
 760                         if (typid == RECORDOID)
 761                                 return TYPEFUNC_RECORD;
 762
 763                         /*
 764                          * We treat VOID and CSTRING as legitimate scalar datatypes,
 765                          * mostly for the convenience of the JDBC driver (which wants to
 766                          * be able to do "SELECT * FROM foo()" for all legitimately
 767                          * user-callable functions).
 768                          */
 769                         if (typid == VOIDOID || typid == CSTRINGOID)
 770                                 return TYPEFUNC_SCALAR;
 771                         return TYPEFUNC_OTHER;
 772         }
 773         /* shouldn't get here, probably */
 774         return TYPEFUNC_OTHER;
 775 }
 776
 777
 778 /*
 779  * get_func_arg_info
 780  *
 781  * Fetch info about the argument types, names, and IN/OUT modes from the
 782  * pg_proc tuple.  Return value is the total number of arguments.
 783  * Other results are palloc'd.  *p_argtypes is always filled in, but
 784  * *p_argnames and *p_argmodes will be set NULL in the default cases
 785  * (no names, and all IN arguments, respectively).
 786  *
 787  * Note that this function simply fetches what is in the pg_proc tuple;
 788  * it doesn't do any interpretation of polymorphic types.
 789  */
 790 int
 791 get_func_arg_info(HeapTuple procTup,
 792                                   Oid **p_argtypes, char ***p_argnames, char **p_argmodes)
 793 {
 794         Form_pg_proc procStruct = (Form_pg_proc) GETSTRUCT(procTup);
 795         Datum           proallargtypes;
 796         Datum           proargmodes;
 797         Datum           proargnames;
 798         bool            isNull;
 799         ArrayType  *arr;
 800         int                     numargs;
 801         Datum      *elems;
 802         int                     nelems;
 803         int                     i;
 804
 805         /* First discover the total number of parameters and get their types */
 806         proallargtypes = SysCacheGetAttr(PROCOID, procTup,
 807                                                                          Anum_pg_proc_proallargtypes,
 808                                                                          &isNull);
 809         if (!isNull)
 810         {
 811                 /*
 812                  * We expect the arrays to be 1-D arrays of the right types; verify
 813                  * that.  For the OID and char arrays, we don't need to use
 814                  * deconstruct_array() since the array data is just going to look like
 815                  * a C array of values.
 816                  */
 817                 arr = DatumGetArrayTypeP(proallargtypes);               /* ensure not toasted */
 818                 numargs = ARR_DIMS(arr)[0];
 819                 if (ARR_NDIM(arr) != 1 ||
 820                         numargs < 0 ||
 821                         ARR_HASNULL(arr) ||
 822                         ARR_ELEMTYPE(arr) != OIDOID)
 823                         elog(ERROR, "proallargtypes is not a 1-D Oid array");
 824                 Assert(numargs >= procStruct->pronargs);
 825                 *p_argtypes = (Oid *) palloc(numargs * sizeof(Oid));
 826                 memcpy(*p_argtypes, ARR_DATA_PTR(arr),
 827                            numargs * sizeof(Oid));
 828         }
 829         else
 830         {
 831                 /* If no proallargtypes, use proargtypes */
 832                 numargs = procStruct->proargtypes.dim1;
 833                 Assert(numargs == procStruct->pronargs);
 834                 *p_argtypes = (Oid *) palloc(numargs * sizeof(Oid));
 835                 memcpy(*p_argtypes, procStruct->proargtypes.values,
 836                            numargs * sizeof(Oid));
 837         }
 838
 839         /* Get argument names, if available */
 840         proargnames = SysCacheGetAttr(PROCOID, procTup,
 841                                                                   Anum_pg_proc_proargnames,
 842                                                                   &isNull);
 843         if (isNull)
 844                 *p_argnames = NULL;
 845         else
 846         {
 847                 deconstruct_array(DatumGetArrayTypeP(proargnames),
 848                                                   TEXTOID, -1, false, 'i',
 849                                                   &elems, NULL, &nelems);
 850                 if (nelems != numargs)  /* should not happen */
 851                         elog(ERROR, "proargnames must have the same number of elements as the function has arguments");
 852                 *p_argnames = (char **) palloc(sizeof(char *) * numargs);
 853                 for (i = 0; i < numargs; i++)
 854                         (*p_argnames)[i] = TextDatumGetCString(elems[i]);
 855         }
 856
 857         /* Get argument modes, if available */
 858         proargmodes = SysCacheGetAttr(PROCOID, procTup,
 859                                                                   Anum_pg_proc_proargmodes,
 860                                                                   &isNull);
 861         if (isNull)
 862                 *p_argmodes = NULL;
 863         else
 864         {
 865                 arr = DatumGetArrayTypeP(proargmodes);  /* ensure not toasted */
 866                 if (ARR_NDIM(arr) != 1 ||
 867                         ARR_DIMS(arr)[0] != numargs ||
 868                         ARR_HASNULL(arr) ||
 869                         ARR_ELEMTYPE(arr) != CHAROID)
 870                         elog(ERROR, "proargmodes is not a 1-D char array");
 871                 *p_argmodes = (char *) palloc(numargs * sizeof(char));
 872                 memcpy(*p_argmodes, ARR_DATA_PTR(arr),
 873                            numargs * sizeof(char));
 874         }
 875
 876         return numargs;
 877 }
 878
 879
 880 /*
 881  * get_func_input_arg_names
 882  *
 883  * Extract the names of input arguments only, given a function's
 884  * proargnames and proargmodes entries in Datum form.
 885  *
 886  * Returns the number of input arguments, which is the length of the
 887  * palloc'd array returned to *arg_names.  Entries for unnamed args
 888  * are set to NULL.  You don't get anything if proargnames is NULL.
 889  */
 890 int
 891 get_func_input_arg_names(Datum proargnames, Datum proargmodes,
 892                                                  char ***arg_names)
 893 {
 894         ArrayType  *arr;
 895         int                     numargs;
 896         Datum      *argnames;
 897         char       *argmodes;
 898         char      **inargnames;
 899         int                     numinargs;
 900         int                     i;
 901
 902         /* Do nothing if null proargnames */
 903         if (proargnames == PointerGetDatum(NULL))
 904         {
 905                 *arg_names = NULL;
 906                 return 0;
 907         }
 908
 909         /*
 910          * We expect the arrays to be 1-D arrays of the right types; verify that.
 911          * For proargmodes, we don't need to use deconstruct_array() since the
 912          * array data is just going to look like a C array of values.
 913          */
 914         arr = DatumGetArrayTypeP(proargnames);          /* ensure not toasted */
 915         if (ARR_NDIM(arr) != 1 ||
 916                 ARR_HASNULL(arr) ||
 917                 ARR_ELEMTYPE(arr) != TEXTOID)
 918                 elog(ERROR, "proargnames is not a 1-D text array");
 919         deconstruct_array(arr, TEXTOID, -1, false, 'i',
 920                                           &argnames, NULL, &numargs);
 921         if (proargmodes != PointerGetDatum(NULL))
 922         {
 923                 arr = DatumGetArrayTypeP(proargmodes);  /* ensure not toasted */
 924                 if (ARR_NDIM(arr) != 1 ||
 925                         ARR_DIMS(arr)[0] != numargs ||
 926                         ARR_HASNULL(arr) ||
 927                         ARR_ELEMTYPE(arr) != CHAROID)
 928                         elog(ERROR, "proargmodes is not a 1-D char array");
 929                 argmodes = (char *) ARR_DATA_PTR(arr);
 930         }
 931         else
 932                 argmodes = NULL;
 933
 934         /* zero elements probably shouldn't happen, but handle it gracefully */
 935         if (numargs <= 0)
 936         {
 937                 *arg_names = NULL;
 938                 return 0;
 939         }
 940
 941         /* extract input-argument names */
 942         inargnames = (char **) palloc(numargs * sizeof(char *));
 943         numinargs = 0;
 944         for (i = 0; i < numargs; i++)
 945         {
 946                 if (argmodes == NULL ||
 947                         argmodes[i] == PROARGMODE_IN ||
 948                         argmodes[i] == PROARGMODE_INOUT ||
 949                         argmodes[i] == PROARGMODE_VARIADIC)
 950                 {
 951                         char       *pname = TextDatumGetCString(argnames[i]);
 952
 953                         if (pname[0] != '\0')
 954                                 inargnames[numinargs] = pname;
 955                         else
 956                                 inargnames[numinargs] = NULL;
 957                         numinargs++;
 958                 }
 959         }
 960
 961         *arg_names = inargnames;
 962         return numinargs;
 963 }
 964
 965
 966 /*
 967  * get_func_result_name
 968  *
 969  * If the function has exactly one output parameter, and that parameter
 970  * is named, return the name (as a palloc'd string).  Else return NULL.
 971  *
 972  * This is used to determine the default output column name for functions
 973  * returning scalar types.
 974  */
 975 char *
 976 get_func_result_name(Oid functionId)
 977 {
 978         char       *result;
 979         HeapTuple       procTuple;
 980         Datum           proargmodes;
 981         Datum           proargnames;
 982         bool            isnull;
 983         ArrayType  *arr;
 984         int                     numargs;
 985         char       *argmodes;
 986         Datum      *argnames;
 987         int                     numoutargs;
 988         int                     nargnames;
 989         int                     i;
 990
 991         /* First fetch the function's pg_proc row */
 992         procTuple = SearchSysCache1(PROCOID, ObjectIdGetDatum(functionId));
 993         if (!HeapTupleIsValid(procTuple))
 994                 elog(ERROR, "cache lookup failed for function %u", functionId);
 995
 996         /* If there are no named OUT parameters, return NULL */
 997         if (heap_attisnull(procTuple, Anum_pg_proc_proargmodes) ||
 998                 heap_attisnull(procTuple, Anum_pg_proc_proargnames))
 999                 result = NULL;
1000         else
1001         {
1002                 /* Get the data out of the tuple */
1003                 proargmodes = SysCacheGetAttr(PROCOID, procTuple,
1004                                                                           Anum_pg_proc_proargmodes,
1005                                                                           &isnull);
1006                 Assert(!isnull);
1007                 proargnames = SysCacheGetAttr(PROCOID, procTuple,
1008                                                                           Anum_pg_proc_proargnames,
1009                                                                           &isnull);
1010                 Assert(!isnull);
1011
1012                 /*
1013                  * We expect the arrays to be 1-D arrays of the right types; verify
1014                  * that.  For the char array, we don't need to use deconstruct_array()
1015                  * since the array data is just going to look like a C array of
1016                  * values.
1017                  */
1018                 arr = DatumGetArrayTypeP(proargmodes);  /* ensure not toasted */
1019                 numargs = ARR_DIMS(arr)[0];
1020                 if (ARR_NDIM(arr) != 1 ||
1021                         numargs < 0 ||
1022                         ARR_HASNULL(arr) ||
1023                         ARR_ELEMTYPE(arr) != CHAROID)
1024                         elog(ERROR, "proargmodes is not a 1-D char array");
1025                 argmodes = (char *) ARR_DATA_PTR(arr);
1026                 arr = DatumGetArrayTypeP(proargnames);  /* ensure not toasted */
1027                 if (ARR_NDIM(arr) != 1 ||
1028                         ARR_DIMS(arr)[0] != numargs ||
1029                         ARR_HASNULL(arr) ||
1030                         ARR_ELEMTYPE(arr) != TEXTOID)
1031                         elog(ERROR, "proargnames is not a 1-D text array");
1032                 deconstruct_array(arr, TEXTOID, -1, false, 'i',
1033                                                   &argnames, NULL, &nargnames);
1034                 Assert(nargnames == numargs);
1035
1036                 /* scan for output argument(s) */
1037                 result = NULL;
1038                 numoutargs = 0;
1039                 for (i = 0; i < numargs; i++)
1040                 {
1041                         if (argmodes[i] == PROARGMODE_IN ||
1042                                 argmodes[i] == PROARGMODE_VARIADIC)
1043                                 continue;
1044                         Assert(argmodes[i] == PROARGMODE_OUT ||
1045                                    argmodes[i] == PROARGMODE_INOUT ||
1046                                    argmodes[i] == PROARGMODE_TABLE);
1047                         if (++numoutargs > 1)
1048                         {
1049                                 /* multiple out args, so forget it */
1050                                 result = NULL;
1051                                 break;
1052                         }
1053                         result = TextDatumGetCString(argnames[i]);
1054                         if (result == NULL || result[0] == '\0')
1055                         {
1056                                 /* Parameter is not named, so forget it */
1057                                 result = NULL;
1058                                 break;
1059                         }
1060                 }
1061         }
1062
1063         ReleaseSysCache(procTuple);
1064
1065         return result;
1066 }
1067
1068
1069 /*
1070  * build_function_result_tupdesc_t
1071  *
1072  * Given a pg_proc row for a function, return a tuple descriptor for the
1073  * result rowtype, or NULL if the function does not have OUT parameters.
1074  *
1075  * Note that this does not handle resolution of polymorphic types;
1076  * that is deliberate.
1077  */
1078 TupleDesc
1079 build_function_result_tupdesc_t(HeapTuple procTuple)
1080 {
1081         Form_pg_proc procform = (Form_pg_proc) GETSTRUCT(procTuple);
1082         Datum           proallargtypes;
1083         Datum           proargmodes;
1084         Datum           proargnames;
1085         bool            isnull;
1086
1087         /* Return NULL if the function isn't declared to return RECORD */
1088         if (procform->prorettype != RECORDOID)
1089                 return NULL;
1090
1091         /* If there are no OUT parameters, return NULL */
1092         if (heap_attisnull(procTuple, Anum_pg_proc_proallargtypes) ||
1093                 heap_attisnull(procTuple, Anum_pg_proc_proargmodes))
1094                 return NULL;
1095
1096         /* Get the data out of the tuple */
1097         proallargtypes = SysCacheGetAttr(PROCOID, procTuple,
1098                                                                          Anum_pg_proc_proallargtypes,
1099                                                                          &isnull);
1100         Assert(!isnull);
1101         proargmodes = SysCacheGetAttr(PROCOID, procTuple,
1102                                                                   Anum_pg_proc_proargmodes,
1103                                                                   &isnull);
1104         Assert(!isnull);
1105         proargnames = SysCacheGetAttr(PROCOID, procTuple,
1106                                                                   Anum_pg_proc_proargnames,
1107                                                                   &isnull);
1108         if (isnull)
1109                 proargnames = PointerGetDatum(NULL);    /* just to be sure */
1110
1111         return build_function_result_tupdesc_d(proallargtypes,
1112                                                                                    proargmodes,
1113                                                                                    proargnames);
1114 }
1115
1116 /*
1117  * build_function_result_tupdesc_d
1118  *
1119  * Build a RECORD function's tupledesc from the pg_proc proallargtypes,
1120  * proargmodes, and proargnames arrays.  This is split out for the
1121  * convenience of ProcedureCreate, which needs to be able to compute the
1122  * tupledesc before actually creating the function.
1123  *
1124  * Returns NULL if there are not at least two OUT or INOUT arguments.
1125  */
1126 TupleDesc
1127 build_function_result_tupdesc_d(Datum proallargtypes,
1128                                                                 Datum proargmodes,
1129                                                                 Datum proargnames)
1130 {
1131         TupleDesc       desc;
1132         ArrayType  *arr;
1133         int                     numargs;
1134         Oid                *argtypes;
1135         char       *argmodes;
1136         Datum      *argnames = NULL;
1137         Oid                *outargtypes;
1138         char      **outargnames;
1139         int                     numoutargs;
1140         int                     nargnames;
1141         int                     i;
1142
1143         /* Can't have output args if columns are null */
1144         if (proallargtypes == PointerGetDatum(NULL) ||
1145                 proargmodes == PointerGetDatum(NULL))
1146                 return NULL;
1147
1148         /*
1149          * We expect the arrays to be 1-D arrays of the right types; verify that.
1150          * For the OID and char arrays, we don't need to use deconstruct_array()
1151          * since the array data is just going to look like a C array of values.
1152          */
1153         arr = DatumGetArrayTypeP(proallargtypes);       /* ensure not toasted */
1154         numargs = ARR_DIMS(arr)[0];
1155         if (ARR_NDIM(arr) != 1 ||
1156                 numargs < 0 ||
1157                 ARR_HASNULL(arr) ||
1158                 ARR_ELEMTYPE(arr) != OIDOID)
1159                 elog(ERROR, "proallargtypes is not a 1-D Oid array");
1160         argtypes = (Oid *) ARR_DATA_PTR(arr);
1161         arr = DatumGetArrayTypeP(proargmodes);          /* ensure not toasted */
1162         if (ARR_NDIM(arr) != 1 ||
1163                 ARR_DIMS(arr)[0] != numargs ||
1164                 ARR_HASNULL(arr) ||
1165                 ARR_ELEMTYPE(arr) != CHAROID)
1166                 elog(ERROR, "proargmodes is not a 1-D char array");
1167         argmodes = (char *) ARR_DATA_PTR(arr);
1168         if (proargnames != PointerGetDatum(NULL))
1169         {
1170                 arr = DatumGetArrayTypeP(proargnames);  /* ensure not toasted */
1171                 if (ARR_NDIM(arr) != 1 ||
1172                         ARR_DIMS(arr)[0] != numargs ||
1173                         ARR_HASNULL(arr) ||
1174                         ARR_ELEMTYPE(arr) != TEXTOID)
1175                         elog(ERROR, "proargnames is not a 1-D text array");
1176                 deconstruct_array(arr, TEXTOID, -1, false, 'i',
1177                                                   &argnames, NULL, &nargnames);
1178                 Assert(nargnames == numargs);
1179         }
1180
1181         /* zero elements probably shouldn't happen, but handle it gracefully */
1182         if (numargs <= 0)
1183                 return NULL;
1184
1185         /* extract output-argument types and names */
1186         outargtypes = (Oid *) palloc(numargs * sizeof(Oid));
1187         outargnames = (char **) palloc(numargs * sizeof(char *));
1188         numoutargs = 0;
1189         for (i = 0; i < numargs; i++)
1190         {
1191                 char       *pname;
1192
1193                 if (argmodes[i] == PROARGMODE_IN ||
1194                         argmodes[i] == PROARGMODE_VARIADIC)
1195                         continue;
1196                 Assert(argmodes[i] == PROARGMODE_OUT ||
1197                            argmodes[i] == PROARGMODE_INOUT ||
1198                            argmodes[i] == PROARGMODE_TABLE);
1199                 outargtypes[numoutargs] = argtypes[i];
1200                 if (argnames)
1201                         pname = TextDatumGetCString(argnames[i]);
1202                 else
1203                         pname = NULL;
1204                 if (pname == NULL || pname[0] == '\0')
1205                 {
1206                         /* Parameter is not named, so gin up a column name */
1207                         pname = (char *) palloc(32);
1208                         snprintf(pname, 32, "column%d", numoutargs + 1);
1209                 }
1210                 outargnames[numoutargs] = pname;
1211                 numoutargs++;
1212         }
1213
1214         /*
1215          * If there is no output argument, or only one, the function does not
1216          * return tuples.
1217          */
1218         if (numoutargs < 2)
1219                 return NULL;
1220
1221         desc = CreateTemplateTupleDesc(numoutargs, false);
1222         for (i = 0; i < numoutargs; i++)
1223         {
1224                 TupleDescInitEntry(desc, i + 1,
1225                                                    outargnames[i],
1226                                                    outargtypes[i],
1227                                                    -1,
1228                                                    0);
1229         }
1230
1231         return desc;
1232 }
1233
1234
1235 /*
1236  * RelationNameGetTupleDesc
1237  *
1238  * Given a (possibly qualified) relation name, build a TupleDesc.
1239  *
1240  * Note: while this works as advertised, it's seldom the best way to
1241  * build a tupdesc for a function's result type.  It's kept around
1242  * only for backwards compatibility with existing user-written code.
1243  */
1244 TupleDesc
1245 RelationNameGetTupleDesc(const char *relname)
1246 {
1247         RangeVar   *relvar;
1248         Relation        rel;
1249         TupleDesc       tupdesc;
1250         List       *relname_list;
1251
1252         /* Open relation and copy the tuple description */
1253         relname_list = stringToQualifiedNameList(relname);
1254         relvar = makeRangeVarFromNameList(relname_list);
1255         rel = relation_openrv(relvar, AccessShareLock);
1256         tupdesc = CreateTupleDescCopy(RelationGetDescr(rel));
1257         relation_close(rel, AccessShareLock);
1258
1259         return tupdesc;
1260 }
1261
1262 /*
1263  * TypeGetTupleDesc
1264  *
1265  * Given a type Oid, build a TupleDesc.  (In most cases you should be
1266  * using get_call_result_type or one of its siblings instead of this
1267  * routine, so that you can handle OUT parameters, RECORD result type,
1268  * and polymorphic results.)
1269  *
1270  * If the type is composite, *and* a colaliases List is provided, *and*
1271  * the List is of natts length, use the aliases instead of the relation
1272  * attnames.  (NB: this usage is deprecated since it may result in
1273  * creation of unnecessary transient record types.)
1274  *
1275  * If the type is a base type, a single item alias List is required.
1276  */
1277 TupleDesc
1278 TypeGetTupleDesc(Oid typeoid, List *colaliases)
1279 {
1280         TypeFuncClass functypclass = get_type_func_class(typeoid);
1281         TupleDesc       tupdesc = NULL;
1282
1283         /*
1284          * Build a suitable tupledesc representing the output rows
1285          */
1286         if (functypclass == TYPEFUNC_COMPOSITE)
1287         {
1288                 /* Composite data type, e.g. a table's row type */
1289                 tupdesc = lookup_rowtype_tupdesc_copy(typeoid, -1);
1290
1291                 if (colaliases != NIL)
1292                 {
1293                         int                     natts = tupdesc->natts;
1294                         int                     varattno;
1295
1296                         /* does the list length match the number of attributes? */
1297                         if (list_length(colaliases) != natts)
1298                                 ereport(ERROR,
1299                                                 (errcode(ERRCODE_DATATYPE_MISMATCH),
1300                                                  errmsg("number of aliases does not match number of columns")));
1301
1302                         /* OK, use the aliases instead */
1303                         for (varattno = 0; varattno < natts; varattno++)
1304                         {
1305                                 char       *label = strVal(list_nth(colaliases, varattno));
1306
1307                                 if (label != NULL)
1308                                         namestrcpy(&(tupdesc->attrs[varattno]->attname), label);
1309                         }
1310
1311                         /* The tuple type is now an anonymous record type */
1312                         tupdesc->tdtypeid = RECORDOID;
1313                         tupdesc->tdtypmod = -1;
1314                 }
1315         }
1316         else if (functypclass == TYPEFUNC_SCALAR)
1317         {
1318                 /* Base data type, i.e. scalar */
1319                 char       *attname;
1320
1321                 /* the alias list is required for base types */
1322                 if (colaliases == NIL)
1323                         ereport(ERROR,
1324                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
1325                                          errmsg("no column alias was provided")));
1326
1327                 /* the alias list length must be 1 */
1328                 if (list_length(colaliases) != 1)
1329                         ereport(ERROR,
1330                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
1331                           errmsg("number of aliases does not match number of columns")));
1332
1333                 /* OK, get the column alias */
1334                 attname = strVal(linitial(colaliases));
1335
1336                 tupdesc = CreateTemplateTupleDesc(1, false);
1337                 TupleDescInitEntry(tupdesc,
1338                                                    (AttrNumber) 1,
1339                                                    attname,
1340                                                    typeoid,
1341                                                    -1,
1342                                                    0);
1343         }
1344         else if (functypclass == TYPEFUNC_RECORD)
1345         {
1346                 /* XXX can't support this because typmod wasn't passed in ... */
1347                 ereport(ERROR,
1348                                 (errcode(ERRCODE_DATATYPE_MISMATCH),
1349                                  errmsg("could not determine row description for function returning record")));
1350         }
1351         else
1352         {
1353                 /* crummy error message, but parser should have caught this */
1354                 elog(ERROR, "function in FROM has unsupported return type");
1355         }
1356
1357         return tupdesc;
1358 }