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) 2002-2007, PostgreSQL Global Development Group
   8  *
   9  * IDENTIFICATION
  10  *        $PostgreSQL: pgsql/src/backend/utils/fmgr/funcapi.c,v 1.32 2007/01/05 22:19:43 momjian Exp $
  11  *
  12  *-------------------------------------------------------------------------
  13  */
  14 #include "postgres.h"
  15
  16 #include "access/heapam.h"
  17 #include "catalog/namespace.h"
  18 #include "catalog/pg_proc.h"
  19 #include "catalog/pg_type.h"
  20 #include "funcapi.h"
  21 #include "parser/parse_coerce.h"
  22 #include "parser/parse_expr.h"
  23 #include "utils/array.h"
  24 #include "utils/builtins.h"
  25 #include "utils/lsyscache.h"
  26 #include "utils/syscache.h"
  27 #include "utils/typcache.h"
  28
  29
  30 static void shutdown_MultiFuncCall(Datum arg);
  31 static TypeFuncClass internal_get_result_type(Oid funcid,
  32                                                  Node *call_expr,
  33                                                  ReturnSetInfo *rsinfo,
  34                                                  Oid *resultTypeId,
  35                                                  TupleDesc *resultTupleDesc);
  36 static bool resolve_polymorphic_tupdesc(TupleDesc tupdesc,
  37                                                         oidvector *declared_args,
  38                                                         Node *call_expr);
  39 static TypeFuncClass get_type_func_class(Oid typid);
  40
  41
  42 /*
  43  * init_MultiFuncCall
  44  * Create an empty FuncCallContext data structure
  45  * and do some other basic Multi-function call setup
  46  * and error checking
  47  */
  48 FuncCallContext *
  49 init_MultiFuncCall(PG_FUNCTION_ARGS)
  50 {
  51         FuncCallContext *retval;
  52
  53         /*
  54          * Bail if we're called in the wrong context
  55          */
  56         if (fcinfo->resultinfo == NULL || !IsA(fcinfo->resultinfo, ReturnSetInfo))
  57                 ereport(ERROR,
  58                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
  59                                  errmsg("set-valued function called in context that cannot accept a set")));
  60
  61         if (fcinfo->flinfo->fn_extra == NULL)
  62         {
  63                 /*
  64                  * First call
  65                  */
  66                 ReturnSetInfo *rsi = (ReturnSetInfo *) fcinfo->resultinfo;
  67
  68                 /*
  69                  * Allocate suitably long-lived space and zero it
  70                  */
  71                 retval = (FuncCallContext *)
  72                         MemoryContextAllocZero(fcinfo->flinfo->fn_mcxt,
  73                                                                    sizeof(FuncCallContext));
  74
  75                 /*
  76                  * initialize the elements
  77                  */
  78                 retval->call_cntr = 0;
  79                 retval->max_calls = 0;
  80                 retval->slot = NULL;
  81                 retval->user_fctx = NULL;
  82                 retval->attinmeta = NULL;
  83                 retval->tuple_desc = NULL;
  84                 retval->multi_call_memory_ctx = fcinfo->flinfo->fn_mcxt;
  85
  86                 /*
  87                  * save the pointer for cross-call use
  88                  */
  89                 fcinfo->flinfo->fn_extra = retval;
  90
  91                 /*
  92                  * Ensure we will get shut down cleanly if the exprcontext is not run
  93                  * to completion.
  94                  */
  95                 RegisterExprContextCallback(rsi->econtext,
  96                                                                         shutdown_MultiFuncCall,
  97                                                                         PointerGetDatum(fcinfo->flinfo));
  98         }
  99         else
 100         {
 101                 /* second and subsequent calls */
 102                 elog(ERROR, "init_MultiFuncCall may not be called more than once");
 103
 104                 /* never reached, but keep compiler happy */
 105                 retval = NULL;
 106         }
 107
 108         return retval;
 109 }
 110
 111 /*
 112  * per_MultiFuncCall
 113  *
 114  * Do Multi-function per-call setup
 115  */
 116 FuncCallContext *
 117 per_MultiFuncCall(PG_FUNCTION_ARGS)
 118 {
 119         FuncCallContext *retval = (FuncCallContext *) fcinfo->flinfo->fn_extra;
 120
 121         /*
 122          * Clear the TupleTableSlot, if present.  This is for safety's sake: the
 123          * Slot will be in a long-lived context (it better be, if the
 124          * FuncCallContext is pointing to it), but in most usage patterns the
 125          * tuples stored in it will be in the function's per-tuple context. So at
 126          * the beginning of each call, the Slot will hold a dangling pointer to an
 127          * already-recycled tuple.      We clear it out here.
 128          *
 129          * Note: use of retval->slot is obsolete as of 8.0, and we expect that it
 130          * will always be NULL.  This is just here for backwards compatibility in
 131          * case someone creates a slot anyway.
 132          */
 133         if (retval->slot != NULL)
 134                 ExecClearTuple(retval->slot);
 135
 136         return retval;
 137 }
 138
 139 /*
 140  * end_MultiFuncCall
 141  * Clean up after init_MultiFuncCall
 142  */
 143 void
 144 end_MultiFuncCall(PG_FUNCTION_ARGS, FuncCallContext *funcctx)
 145 {
 146         ReturnSetInfo *rsi = (ReturnSetInfo *) fcinfo->resultinfo;
 147
 148         /* Deregister the shutdown callback */
 149         UnregisterExprContextCallback(rsi->econtext,
 150                                                                   shutdown_MultiFuncCall,
 151                                                                   PointerGetDatum(fcinfo->flinfo));
 152
 153         /* But use it to do the real work */
 154         shutdown_MultiFuncCall(PointerGetDatum(fcinfo->flinfo));
 155 }
 156
 157 /*
 158  * shutdown_MultiFuncCall
 159  * Shutdown function to clean up after init_MultiFuncCall
 160  */
 161 static void
 162 shutdown_MultiFuncCall(Datum arg)
 163 {
 164         FmgrInfo   *flinfo = (FmgrInfo *) DatumGetPointer(arg);
 165         FuncCallContext *funcctx = (FuncCallContext *) flinfo->fn_extra;
 166
 167         /* unbind from flinfo */
 168         flinfo->fn_extra = NULL;
 169
 170         /*
 171          * Caller is responsible to free up memory for individual struct elements
 172          * other than att_in_funcinfo and elements.
 173          */
 174         if (funcctx->attinmeta != NULL)
 175                 pfree(funcctx->attinmeta);
 176
 177         pfree(funcctx);
 178 }
 179
 180
 181 /*
 182  * get_call_result_type
 183  *              Given a function's call info record, determine the kind of datatype
 184  *              it is supposed to return.  If resultTypeId isn't NULL, *resultTypeId
 185  *              receives the actual datatype OID (this is mainly useful for scalar
 186  *              result types).  If resultTupleDesc isn't NULL, *resultTupleDesc
 187  *              receives a pointer to a TupleDesc when the result is of a composite
 188  *              type, or NULL when it's a scalar result.
 189  *
 190  * One hard case that this handles is resolution of actual rowtypes for
 191  * functions returning RECORD (from either the function's OUT parameter
 192  * list, or a ReturnSetInfo context node).      TYPEFUNC_RECORD is returned
 193  * only when we couldn't resolve the actual rowtype for lack of information.
 194  *
 195  * The other hard case that this handles is resolution of polymorphism.
 196  * We will never return ANYELEMENT or ANYARRAY, either as a scalar result
 197  * type or as a component of a rowtype.
 198  *
 199  * This function is relatively expensive --- in a function returning set,
 200  * try to call it only the first time through.
 201  */
 202 TypeFuncClass
 203 get_call_result_type(FunctionCallInfo fcinfo,
 204                                          Oid *resultTypeId,
 205                                          TupleDesc *resultTupleDesc)
 206 {
 207         return internal_get_result_type(fcinfo->flinfo->fn_oid,
 208                                                                         fcinfo->flinfo->fn_expr,
 209                                                                         (ReturnSetInfo *) fcinfo->resultinfo,
 210                                                                         resultTypeId,
 211                                                                         resultTupleDesc);
 212 }
 213
 214 /*
 215  * get_expr_result_type
 216  *              As above, but work from a calling expression node tree
 217  */
 218 TypeFuncClass
 219 get_expr_result_type(Node *expr,
 220                                          Oid *resultTypeId,
 221                                          TupleDesc *resultTupleDesc)
 222 {
 223         TypeFuncClass result;
 224
 225         if (expr && IsA(expr, FuncExpr))
 226                 result = internal_get_result_type(((FuncExpr *) expr)->funcid,
 227                                                                                   expr,
 228                                                                                   NULL,
 229                                                                                   resultTypeId,
 230                                                                                   resultTupleDesc);
 231         else if (expr && IsA(expr, OpExpr))
 232                 result = internal_get_result_type(get_opcode(((OpExpr *) expr)->opno),
 233                                                                                   expr,
 234                                                                                   NULL,
 235                                                                                   resultTypeId,
 236                                                                                   resultTupleDesc);
 237         else
 238         {
 239                 /* handle as a generic expression; no chance to resolve RECORD */
 240                 Oid                     typid = exprType(expr);
 241
 242                 if (resultTypeId)
 243                         *resultTypeId = typid;
 244                 if (resultTupleDesc)
 245                         *resultTupleDesc = NULL;
 246                 result = get_type_func_class(typid);
 247                 if (result == TYPEFUNC_COMPOSITE && resultTupleDesc)
 248                         *resultTupleDesc = lookup_rowtype_tupdesc_copy(typid, -1);
 249         }
 250
 251         return result;
 252 }
 253
 254 /*
 255  * get_func_result_type
 256  *              As above, but work from a function's OID only
 257  *
 258  * This will not be able to resolve pure-RECORD results nor polymorphism.
 259  */
 260 TypeFuncClass
 261 get_func_result_type(Oid functionId,
 262                                          Oid *resultTypeId,
 263                                          TupleDesc *resultTupleDesc)
 264 {
 265         return internal_get_result_type(functionId,
 266                                                                         NULL,
 267                                                                         NULL,
 268                                                                         resultTypeId,
 269                                                                         resultTupleDesc);
 270 }
 271
 272 /*
 273  * internal_get_result_type -- workhorse code implementing all the above
 274  *
 275  * funcid must always be supplied.      call_expr and rsinfo can be NULL if not
 276  * available.  We will return TYPEFUNC_RECORD, and store NULL into
 277  * *resultTupleDesc, if we cannot deduce the complete result rowtype from
 278  * the available information.
 279  */
 280 static TypeFuncClass
 281 internal_get_result_type(Oid funcid,
 282                                                  Node *call_expr,
 283                                                  ReturnSetInfo *rsinfo,
 284                                                  Oid *resultTypeId,
 285                                                  TupleDesc *resultTupleDesc)
 286 {
 287         TypeFuncClass result;
 288         HeapTuple       tp;
 289         Form_pg_proc procform;
 290         Oid                     rettype;
 291         TupleDesc       tupdesc;
 292
 293         /* First fetch the function's pg_proc row to inspect its rettype */
 294         tp = SearchSysCache(PROCOID,
 295                                                 ObjectIdGetDatum(funcid),
 296                                                 0, 0, 0);
 297         if (!HeapTupleIsValid(tp))
 298                 elog(ERROR, "cache lookup failed for function %u", funcid);
 299         procform = (Form_pg_proc) GETSTRUCT(tp);
 300
 301         rettype = procform->prorettype;
 302
 303         /* Check for OUT parameters defining a RECORD result */
 304         tupdesc = build_function_result_tupdesc_t(tp);
 305         if (tupdesc)
 306         {
 307                 /*
 308                  * It has OUT parameters, so it's basically like a regular composite
 309                  * type, except we have to be able to resolve any polymorphic OUT
 310                  * parameters.
 311                  */
 312                 if (resultTypeId)
 313                         *resultTypeId = rettype;
 314
 315                 if (resolve_polymorphic_tupdesc(tupdesc,
 316                                                                                 &procform->proargtypes,
 317                                                                                 call_expr))
 318                 {
 319                         if (tupdesc->tdtypeid == RECORDOID &&
 320                                 tupdesc->tdtypmod < 0)
 321                                 assign_record_type_typmod(tupdesc);
 322                         if (resultTupleDesc)
 323                                 *resultTupleDesc = tupdesc;
 324                         result = TYPEFUNC_COMPOSITE;
 325                 }
 326                 else
 327                 {
 328                         if (resultTupleDesc)
 329                                 *resultTupleDesc = NULL;
 330                         result = TYPEFUNC_RECORD;
 331                 }
 332
 333                 ReleaseSysCache(tp);
 334
 335                 return result;
 336         }
 337
 338         /*
 339          * If scalar polymorphic result, try to resolve it.
 340          */
 341         if (rettype == ANYARRAYOID || rettype == ANYELEMENTOID)
 342         {
 343                 Oid                     newrettype = exprType(call_expr);
 344
 345                 if (newrettype == InvalidOid)   /* this probably should not happen */
 346                         ereport(ERROR,
 347                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
 348                                          errmsg("could not determine actual result type for function \"%s\" declared to return type %s",
 349                                                         NameStr(procform->proname),
 350                                                         format_type_be(rettype))));
 351                 rettype = newrettype;
 352         }
 353
 354         if (resultTypeId)
 355                 *resultTypeId = rettype;
 356         if (resultTupleDesc)
 357                 *resultTupleDesc = NULL;        /* default result */
 358
 359         /* Classify the result type */
 360         result = get_type_func_class(rettype);
 361         switch (result)
 362         {
 363                 case TYPEFUNC_COMPOSITE:
 364                         if (resultTupleDesc)
 365                                 *resultTupleDesc = lookup_rowtype_tupdesc_copy(rettype, -1);
 366                         /* Named composite types can't have any polymorphic columns */
 367                         break;
 368                 case TYPEFUNC_SCALAR:
 369                         break;
 370                 case TYPEFUNC_RECORD:
 371                         /* We must get the tupledesc from call context */
 372                         if (rsinfo && IsA(rsinfo, ReturnSetInfo) &&
 373                                 rsinfo->expectedDesc != NULL)
 374                         {
 375                                 result = TYPEFUNC_COMPOSITE;
 376                                 if (resultTupleDesc)
 377                                         *resultTupleDesc = rsinfo->expectedDesc;
 378                                 /* Assume no polymorphic columns here, either */
 379                         }
 380                         break;
 381                 default:
 382                         break;
 383         }
 384
 385         ReleaseSysCache(tp);
 386
 387         return result;
 388 }
 389
 390 /*
 391  * Given the result tuple descriptor for a function with OUT parameters,
 392  * replace any polymorphic columns (ANYELEMENT/ANYARRAY) with correct data
 393  * types deduced from the input arguments.      Returns TRUE if able to deduce
 394  * all types, FALSE if not.
 395  */
 396 static bool
 397 resolve_polymorphic_tupdesc(TupleDesc tupdesc, oidvector *declared_args,
 398                                                         Node *call_expr)
 399 {
 400         int                     natts = tupdesc->natts;
 401         int                     nargs = declared_args->dim1;
 402         bool            have_anyelement_result = false;
 403         bool            have_anyarray_result = false;
 404         Oid                     anyelement_type = InvalidOid;
 405         Oid                     anyarray_type = InvalidOid;
 406         int                     i;
 407
 408         /* See if there are any polymorphic outputs; quick out if not */
 409         for (i = 0; i < natts; i++)
 410         {
 411                 switch (tupdesc->attrs[i]->atttypid)
 412                 {
 413                         case ANYELEMENTOID:
 414                                 have_anyelement_result = true;
 415                                 break;
 416                         case ANYARRAYOID:
 417                                 have_anyarray_result = true;
 418                                 break;
 419                         default:
 420                                 break;
 421                 }
 422         }
 423         if (!have_anyelement_result && !have_anyarray_result)
 424                 return true;
 425
 426         /*
 427          * Otherwise, extract actual datatype(s) from input arguments.  (We assume
 428          * the parser already validated consistency of the arguments.)
 429          */
 430         if (!call_expr)
 431                 return false;                   /* no hope */
 432
 433         for (i = 0; i < nargs; i++)
 434         {
 435                 switch (declared_args->values[i])
 436                 {
 437                         case ANYELEMENTOID:
 438                                 if (!OidIsValid(anyelement_type))
 439                                         anyelement_type = get_call_expr_argtype(call_expr, i);
 440                                 break;
 441                         case ANYARRAYOID:
 442                                 if (!OidIsValid(anyarray_type))
 443                                         anyarray_type = get_call_expr_argtype(call_expr, i);
 444                                 break;
 445                         default:
 446                                 break;
 447                 }
 448         }
 449
 450         /* If nothing found, parser messed up */
 451         if (!OidIsValid(anyelement_type) && !OidIsValid(anyarray_type))
 452                 return false;
 453
 454         /* If needed, deduce one polymorphic type from the other */
 455         if (have_anyelement_result && !OidIsValid(anyelement_type))
 456                 anyelement_type = resolve_generic_type(ANYELEMENTOID,
 457                                                                                            anyarray_type,
 458                                                                                            ANYARRAYOID);
 459         if (have_anyarray_result && !OidIsValid(anyarray_type))
 460                 anyarray_type = resolve_generic_type(ANYARRAYOID,
 461                                                                                          anyelement_type,
 462                                                                                          ANYELEMENTOID);
 463
 464         /* And finally replace the tuple column types as needed */
 465         for (i = 0; i < natts; i++)
 466         {
 467                 switch (tupdesc->attrs[i]->atttypid)
 468                 {
 469                         case ANYELEMENTOID:
 470                                 TupleDescInitEntry(tupdesc, i + 1,
 471                                                                    NameStr(tupdesc->attrs[i]->attname),
 472                                                                    anyelement_type,
 473                                                                    -1,
 474                                                                    0);
 475                                 break;
 476                         case ANYARRAYOID:
 477                                 TupleDescInitEntry(tupdesc, i + 1,
 478                                                                    NameStr(tupdesc->attrs[i]->attname),
 479                                                                    anyarray_type,
 480                                                                    -1,
 481                                                                    0);
 482                                 break;
 483                         default:
 484                                 break;
 485                 }
 486         }
 487
 488         return true;
 489 }
 490
 491 /*
 492  * Given the declared argument types and modes for a function,
 493  * replace any polymorphic types (ANYELEMENT/ANYARRAY) with correct data
 494  * types deduced from the input arguments.      Returns TRUE if able to deduce
 495  * all types, FALSE if not.  This is the same logic as
 496  * resolve_polymorphic_tupdesc, but with a different argument representation.
 497  *
 498  * argmodes may be NULL, in which case all arguments are assumed to be IN mode.
 499  */
 500 bool
 501 resolve_polymorphic_argtypes(int numargs, Oid *argtypes, char *argmodes,
 502                                                          Node *call_expr)
 503 {
 504         bool            have_anyelement_result = false;
 505         bool            have_anyarray_result = false;
 506         Oid                     anyelement_type = InvalidOid;
 507         Oid                     anyarray_type = InvalidOid;
 508         int                     inargno;
 509         int                     i;
 510
 511         /* First pass: resolve polymorphic inputs, check for outputs */
 512         inargno = 0;
 513         for (i = 0; i < numargs; i++)
 514         {
 515                 char            argmode = argmodes ? argmodes[i] : PROARGMODE_IN;
 516
 517                 switch (argtypes[i])
 518                 {
 519                         case ANYELEMENTOID:
 520                                 if (argmode == PROARGMODE_OUT)
 521                                         have_anyelement_result = true;
 522                                 else
 523                                 {
 524                                         if (!OidIsValid(anyelement_type))
 525                                         {
 526                                                 anyelement_type = get_call_expr_argtype(call_expr,
 527                                                                                                                                 inargno);
 528                                                 if (!OidIsValid(anyelement_type))
 529                                                         return false;
 530                                         }
 531                                         argtypes[i] = anyelement_type;
 532                                 }
 533                                 break;
 534                         case ANYARRAYOID:
 535                                 if (argmode == PROARGMODE_OUT)
 536                                         have_anyarray_result = true;
 537                                 else
 538                                 {
 539                                         if (!OidIsValid(anyarray_type))
 540                                         {
 541                                                 anyarray_type = get_call_expr_argtype(call_expr,
 542                                                                                                                           inargno);
 543                                                 if (!OidIsValid(anyarray_type))
 544                                                         return false;
 545                                         }
 546                                         argtypes[i] = anyarray_type;
 547                                 }
 548                                 break;
 549                         default:
 550                                 break;
 551                 }
 552                 if (argmode != PROARGMODE_OUT)
 553                         inargno++;
 554         }
 555
 556         /* Done? */
 557         if (!have_anyelement_result && !have_anyarray_result)
 558                 return true;
 559
 560         /* If no input polymorphics, parser messed up */
 561         if (!OidIsValid(anyelement_type) && !OidIsValid(anyarray_type))
 562                 return false;
 563
 564         /* If needed, deduce one polymorphic type from the other */
 565         if (have_anyelement_result && !OidIsValid(anyelement_type))
 566                 anyelement_type = resolve_generic_type(ANYELEMENTOID,
 567                                                                                            anyarray_type,
 568                                                                                            ANYARRAYOID);
 569         if (have_anyarray_result && !OidIsValid(anyarray_type))
 570                 anyarray_type = resolve_generic_type(ANYARRAYOID,
 571                                                                                          anyelement_type,
 572                                                                                          ANYELEMENTOID);
 573
 574         /* And finally replace the output column types as needed */
 575         for (i = 0; i < numargs; i++)
 576         {
 577                 switch (argtypes[i])
 578                 {
 579                         case ANYELEMENTOID:
 580                                 argtypes[i] = anyelement_type;
 581                                 break;
 582                         case ANYARRAYOID:
 583                                 argtypes[i] = anyarray_type;
 584                                 break;
 585                         default:
 586                                 break;
 587                 }
 588         }
 589
 590         return true;
 591 }
 592
 593 /*
 594  * get_type_func_class
 595  *              Given the type OID, obtain its TYPEFUNC classification.
 596  *
 597  * This is intended to centralize a bunch of formerly ad-hoc code for
 598  * classifying types.  The categories used here are useful for deciding
 599  * how to handle functions returning the datatype.
 600  */
 601 static TypeFuncClass
 602 get_type_func_class(Oid typid)
 603 {
 604         switch (get_typtype(typid))
 605         {
 606                 case 'c':
 607                         return TYPEFUNC_COMPOSITE;
 608                 case 'b':
 609                 case 'd':
 610                         return TYPEFUNC_SCALAR;
 611                 case 'p':
 612                         if (typid == RECORDOID)
 613                                 return TYPEFUNC_RECORD;
 614
 615                         /*
 616                          * We treat VOID and CSTRING as legitimate scalar datatypes,
 617                          * mostly for the convenience of the JDBC driver (which wants to
 618                          * be able to do "SELECT * FROM foo()" for all legitimately
 619                          * user-callable functions).
 620                          */
 621                         if (typid == VOIDOID || typid == CSTRINGOID)
 622                                 return TYPEFUNC_SCALAR;
 623                         return TYPEFUNC_OTHER;
 624         }
 625         /* shouldn't get here, probably */
 626         return TYPEFUNC_OTHER;
 627 }
 628
 629
 630 /*
 631  * get_func_arg_info
 632  *
 633  * Fetch info about the argument types, names, and IN/OUT modes from the
 634  * pg_proc tuple.  Return value is the total number of arguments.
 635  * Other results are palloc'd.  *p_argtypes is always filled in, but
 636  * *p_argnames and *p_argmodes will be set NULL in the default cases
 637  * (no names, and all IN arguments, respectively).
 638  *
 639  * Note that this function simply fetches what is in the pg_proc tuple;
 640  * it doesn't do any interpretation of polymorphic types.
 641  */
 642 int
 643 get_func_arg_info(HeapTuple procTup,
 644                                   Oid **p_argtypes, char ***p_argnames, char **p_argmodes)
 645 {
 646         Form_pg_proc procStruct = (Form_pg_proc) GETSTRUCT(procTup);
 647         Datum           proallargtypes;
 648         Datum           proargmodes;
 649         Datum           proargnames;
 650         bool            isNull;
 651         ArrayType  *arr;
 652         int                     numargs;
 653         Datum      *elems;
 654         int                     nelems;
 655         int                     i;
 656
 657         /* First discover the total number of parameters and get their types */
 658         proallargtypes = SysCacheGetAttr(PROCOID, procTup,
 659                                                                          Anum_pg_proc_proallargtypes,
 660                                                                          &isNull);
 661         if (!isNull)
 662         {
 663                 /*
 664                  * We expect the arrays to be 1-D arrays of the right types; verify
 665                  * that.  For the OID and char arrays, we don't need to use
 666                  * deconstruct_array() since the array data is just going to look like
 667                  * a C array of values.
 668                  */
 669                 arr = DatumGetArrayTypeP(proallargtypes);               /* ensure not toasted */
 670                 numargs = ARR_DIMS(arr)[0];
 671                 if (ARR_NDIM(arr) != 1 ||
 672                         numargs < 0 ||
 673                         ARR_HASNULL(arr) ||
 674                         ARR_ELEMTYPE(arr) != OIDOID)
 675                         elog(ERROR, "proallargtypes is not a 1-D Oid array");
 676                 Assert(numargs >= procStruct->pronargs);
 677                 *p_argtypes = (Oid *) palloc(numargs * sizeof(Oid));
 678                 memcpy(*p_argtypes, ARR_DATA_PTR(arr),
 679                            numargs * sizeof(Oid));
 680         }
 681         else
 682         {
 683                 /* If no proallargtypes, use proargtypes */
 684                 numargs = procStruct->proargtypes.dim1;
 685                 Assert(numargs == procStruct->pronargs);
 686                 *p_argtypes = (Oid *) palloc(numargs * sizeof(Oid));
 687                 memcpy(*p_argtypes, procStruct->proargtypes.values,
 688                            numargs * sizeof(Oid));
 689         }
 690
 691         /* Get argument names, if available */
 692         proargnames = SysCacheGetAttr(PROCOID, procTup,
 693                                                                   Anum_pg_proc_proargnames,
 694                                                                   &isNull);
 695         if (isNull)
 696                 *p_argnames = NULL;
 697         else
 698         {
 699                 deconstruct_array(DatumGetArrayTypeP(proargnames),
 700                                                   TEXTOID, -1, false, 'i',
 701                                                   &elems, NULL, &nelems);
 702                 if (nelems != numargs)  /* should not happen */
 703                         elog(ERROR, "proargnames must have the same number of elements as the function has arguments");
 704                 *p_argnames = (char **) palloc(sizeof(char *) * numargs);
 705                 for (i = 0; i < numargs; i++)
 706                         (*p_argnames)[i] = DatumGetCString(DirectFunctionCall1(textout,
 707                                                                                                                                    elems[i]));
 708         }
 709
 710         /* Get argument modes, if available */
 711         proargmodes = SysCacheGetAttr(PROCOID, procTup,
 712                                                                   Anum_pg_proc_proargmodes,
 713                                                                   &isNull);
 714         if (isNull)
 715                 *p_argmodes = NULL;
 716         else
 717         {
 718                 arr = DatumGetArrayTypeP(proargmodes);  /* ensure not toasted */
 719                 if (ARR_NDIM(arr) != 1 ||
 720                         ARR_DIMS(arr)[0] != numargs ||
 721                         ARR_HASNULL(arr) ||
 722                         ARR_ELEMTYPE(arr) != CHAROID)
 723                         elog(ERROR, "proargmodes is not a 1-D char array");
 724                 *p_argmodes = (char *) palloc(numargs * sizeof(char));
 725                 memcpy(*p_argmodes, ARR_DATA_PTR(arr),
 726                            numargs * sizeof(char));
 727         }
 728
 729         return numargs;
 730 }
 731
 732
 733 /*
 734  * get_func_result_name
 735  *
 736  * If the function has exactly one output parameter, and that parameter
 737  * is named, return the name (as a palloc'd string).  Else return NULL.
 738  *
 739  * This is used to determine the default output column name for functions
 740  * returning scalar types.
 741  */
 742 char *
 743 get_func_result_name(Oid functionId)
 744 {
 745         char       *result;
 746         HeapTuple       procTuple;
 747         Datum           proargmodes;
 748         Datum           proargnames;
 749         bool            isnull;
 750         ArrayType  *arr;
 751         int                     numargs;
 752         char       *argmodes;
 753         Datum      *argnames;
 754         int                     numoutargs;
 755         int                     nargnames;
 756         int                     i;
 757
 758         /* First fetch the function's pg_proc row */
 759         procTuple = SearchSysCache(PROCOID,
 760                                                            ObjectIdGetDatum(functionId),
 761                                                            0, 0, 0);
 762         if (!HeapTupleIsValid(procTuple))
 763                 elog(ERROR, "cache lookup failed for function %u", functionId);
 764
 765         /* If there are no named OUT parameters, return NULL */
 766         if (heap_attisnull(procTuple, Anum_pg_proc_proargmodes) ||
 767                 heap_attisnull(procTuple, Anum_pg_proc_proargnames))
 768                 result = NULL;
 769         else
 770         {
 771                 /* Get the data out of the tuple */
 772                 proargmodes = SysCacheGetAttr(PROCOID, procTuple,
 773                                                                           Anum_pg_proc_proargmodes,
 774                                                                           &isnull);
 775                 Assert(!isnull);
 776                 proargnames = SysCacheGetAttr(PROCOID, procTuple,
 777                                                                           Anum_pg_proc_proargnames,
 778                                                                           &isnull);
 779                 Assert(!isnull);
 780
 781                 /*
 782                  * We expect the arrays to be 1-D arrays of the right types; verify
 783                  * that.  For the char array, we don't need to use deconstruct_array()
 784                  * since the array data is just going to look like a C array of
 785                  * values.
 786                  */
 787                 arr = DatumGetArrayTypeP(proargmodes);  /* ensure not toasted */
 788                 numargs = ARR_DIMS(arr)[0];
 789                 if (ARR_NDIM(arr) != 1 ||
 790                         numargs < 0 ||
 791                         ARR_HASNULL(arr) ||
 792                         ARR_ELEMTYPE(arr) != CHAROID)
 793                         elog(ERROR, "proargmodes is not a 1-D char array");
 794                 argmodes = (char *) ARR_DATA_PTR(arr);
 795                 arr = DatumGetArrayTypeP(proargnames);  /* ensure not toasted */
 796                 if (ARR_NDIM(arr) != 1 ||
 797                         ARR_DIMS(arr)[0] != numargs ||
 798                         ARR_HASNULL(arr) ||
 799                         ARR_ELEMTYPE(arr) != TEXTOID)
 800                         elog(ERROR, "proargnames is not a 1-D text array");
 801                 deconstruct_array(arr, TEXTOID, -1, false, 'i',
 802                                                   &argnames, NULL, &nargnames);
 803                 Assert(nargnames == numargs);
 804
 805                 /* scan for output argument(s) */
 806                 result = NULL;
 807                 numoutargs = 0;
 808                 for (i = 0; i < numargs; i++)
 809                 {
 810                         if (argmodes[i] == PROARGMODE_IN)
 811                                 continue;
 812                         Assert(argmodes[i] == PROARGMODE_OUT ||
 813                                    argmodes[i] == PROARGMODE_INOUT);
 814                         if (++numoutargs > 1)
 815                         {
 816                                 /* multiple out args, so forget it */
 817                                 result = NULL;
 818                                 break;
 819                         }
 820                         result = DatumGetCString(DirectFunctionCall1(textout,
 821                                                                                                                  argnames[i]));
 822                         if (result == NULL || result[0] == '\0')
 823                         {
 824                                 /* Parameter is not named, so forget it */
 825                                 result = NULL;
 826                                 break;
 827                         }
 828                 }
 829         }
 830
 831         ReleaseSysCache(procTuple);
 832
 833         return result;
 834 }
 835
 836
 837 /*
 838  * build_function_result_tupdesc_t
 839  *
 840  * Given a pg_proc row for a function, return a tuple descriptor for the
 841  * result rowtype, or NULL if the function does not have OUT parameters.
 842  *
 843  * Note that this does not handle resolution of ANYELEMENT/ANYARRAY types;
 844  * that is deliberate.
 845  */
 846 TupleDesc
 847 build_function_result_tupdesc_t(HeapTuple procTuple)
 848 {
 849         Form_pg_proc procform = (Form_pg_proc) GETSTRUCT(procTuple);
 850         Datum           proallargtypes;
 851         Datum           proargmodes;
 852         Datum           proargnames;
 853         bool            isnull;
 854
 855         /* Return NULL if the function isn't declared to return RECORD */
 856         if (procform->prorettype != RECORDOID)
 857                 return NULL;
 858
 859         /* If there are no OUT parameters, return NULL */
 860         if (heap_attisnull(procTuple, Anum_pg_proc_proallargtypes) ||
 861                 heap_attisnull(procTuple, Anum_pg_proc_proargmodes))
 862                 return NULL;
 863
 864         /* Get the data out of the tuple */
 865         proallargtypes = SysCacheGetAttr(PROCOID, procTuple,
 866                                                                          Anum_pg_proc_proallargtypes,
 867                                                                          &isnull);
 868         Assert(!isnull);
 869         proargmodes = SysCacheGetAttr(PROCOID, procTuple,
 870                                                                   Anum_pg_proc_proargmodes,
 871                                                                   &isnull);
 872         Assert(!isnull);
 873         proargnames = SysCacheGetAttr(PROCOID, procTuple,
 874                                                                   Anum_pg_proc_proargnames,
 875                                                                   &isnull);
 876         if (isnull)
 877                 proargnames = PointerGetDatum(NULL);    /* just to be sure */
 878
 879         return build_function_result_tupdesc_d(proallargtypes,
 880                                                                                    proargmodes,
 881                                                                                    proargnames);
 882 }
 883
 884 /*
 885  * build_function_result_tupdesc_d
 886  *
 887  * Build a RECORD function's tupledesc from the pg_proc proallargtypes,
 888  * proargmodes, and proargnames arrays.  This is split out for the
 889  * convenience of ProcedureCreate, which needs to be able to compute the
 890  * tupledesc before actually creating the function.
 891  *
 892  * Returns NULL if there are not at least two OUT or INOUT arguments.
 893  */
 894 TupleDesc
 895 build_function_result_tupdesc_d(Datum proallargtypes,
 896                                                                 Datum proargmodes,
 897                                                                 Datum proargnames)
 898 {
 899         TupleDesc       desc;
 900         ArrayType  *arr;
 901         int                     numargs;
 902         Oid                *argtypes;
 903         char       *argmodes;
 904         Datum      *argnames = NULL;
 905         Oid                *outargtypes;
 906         char      **outargnames;
 907         int                     numoutargs;
 908         int                     nargnames;
 909         int                     i;
 910
 911         /* Can't have output args if columns are null */
 912         if (proallargtypes == PointerGetDatum(NULL) ||
 913                 proargmodes == PointerGetDatum(NULL))
 914                 return NULL;
 915
 916         /*
 917          * We expect the arrays to be 1-D arrays of the right types; verify that.
 918          * For the OID and char arrays, we don't need to use deconstruct_array()
 919          * since the array data is just going to look like a C array of values.
 920          */
 921         arr = DatumGetArrayTypeP(proallargtypes);       /* ensure not toasted */
 922         numargs = ARR_DIMS(arr)[0];
 923         if (ARR_NDIM(arr) != 1 ||
 924                 numargs < 0 ||
 925                 ARR_HASNULL(arr) ||
 926                 ARR_ELEMTYPE(arr) != OIDOID)
 927                 elog(ERROR, "proallargtypes is not a 1-D Oid array");
 928         argtypes = (Oid *) ARR_DATA_PTR(arr);
 929         arr = DatumGetArrayTypeP(proargmodes);          /* ensure not toasted */
 930         if (ARR_NDIM(arr) != 1 ||
 931                 ARR_DIMS(arr)[0] != numargs ||
 932                 ARR_HASNULL(arr) ||
 933                 ARR_ELEMTYPE(arr) != CHAROID)
 934                 elog(ERROR, "proargmodes is not a 1-D char array");
 935         argmodes = (char *) ARR_DATA_PTR(arr);
 936         if (proargnames != PointerGetDatum(NULL))
 937         {
 938                 arr = DatumGetArrayTypeP(proargnames);  /* ensure not toasted */
 939                 if (ARR_NDIM(arr) != 1 ||
 940                         ARR_DIMS(arr)[0] != numargs ||
 941                         ARR_HASNULL(arr) ||
 942                         ARR_ELEMTYPE(arr) != TEXTOID)
 943                         elog(ERROR, "proargnames is not a 1-D text array");
 944                 deconstruct_array(arr, TEXTOID, -1, false, 'i',
 945                                                   &argnames, NULL, &nargnames);
 946                 Assert(nargnames == numargs);
 947         }
 948
 949         /* zero elements probably shouldn't happen, but handle it gracefully */
 950         if (numargs <= 0)
 951                 return NULL;
 952
 953         /* extract output-argument types and names */
 954         outargtypes = (Oid *) palloc(numargs * sizeof(Oid));
 955         outargnames = (char **) palloc(numargs * sizeof(char *));
 956         numoutargs = 0;
 957         for (i = 0; i < numargs; i++)
 958         {
 959                 char       *pname;
 960
 961                 if (argmodes[i] == PROARGMODE_IN)
 962                         continue;
 963                 Assert(argmodes[i] == PROARGMODE_OUT ||
 964                            argmodes[i] == PROARGMODE_INOUT);
 965                 outargtypes[numoutargs] = argtypes[i];
 966                 if (argnames)
 967                         pname = DatumGetCString(DirectFunctionCall1(textout, argnames[i]));
 968                 else
 969                         pname = NULL;
 970                 if (pname == NULL || pname[0] == '\0')
 971                 {
 972                         /* Parameter is not named, so gin up a column name */
 973                         pname = (char *) palloc(32);
 974                         snprintf(pname, 32, "column%d", numoutargs + 1);
 975                 }
 976                 outargnames[numoutargs] = pname;
 977                 numoutargs++;
 978         }
 979
 980         /*
 981          * If there is no output argument, or only one, the function does not
 982          * return tuples.
 983          */
 984         if (numoutargs < 2)
 985                 return NULL;
 986
 987         desc = CreateTemplateTupleDesc(numoutargs, false);
 988         for (i = 0; i < numoutargs; i++)
 989         {
 990                 TupleDescInitEntry(desc, i + 1,
 991                                                    outargnames[i],
 992                                                    outargtypes[i],
 993                                                    -1,
 994                                                    0);
 995         }
 996
 997         return desc;
 998 }
 999
1000
1001 /*
1002  * RelationNameGetTupleDesc
1003  *
1004  * Given a (possibly qualified) relation name, build a TupleDesc.
1005  *
1006  * Note: while this works as advertised, it's seldom the best way to
1007  * build a tupdesc for a function's result type.  It's kept around
1008  * only for backwards compatibility with existing user-written code.
1009  */
1010 TupleDesc
1011 RelationNameGetTupleDesc(const char *relname)
1012 {
1013         RangeVar   *relvar;
1014         Relation        rel;
1015         TupleDesc       tupdesc;
1016         List       *relname_list;
1017
1018         /* Open relation and copy the tuple description */
1019         relname_list = stringToQualifiedNameList(relname, "RelationNameGetTupleDesc");
1020         relvar = makeRangeVarFromNameList(relname_list);
1021         rel = relation_openrv(relvar, AccessShareLock);
1022         tupdesc = CreateTupleDescCopy(RelationGetDescr(rel));
1023         relation_close(rel, AccessShareLock);
1024
1025         return tupdesc;
1026 }
1027
1028 /*
1029  * TypeGetTupleDesc
1030  *
1031  * Given a type Oid, build a TupleDesc.  (In most cases you should be
1032  * using get_call_result_type or one of its siblings instead of this
1033  * routine, so that you can handle OUT parameters, RECORD result type,
1034  * and polymorphic results.)
1035  *
1036  * If the type is composite, *and* a colaliases List is provided, *and*
1037  * the List is of natts length, use the aliases instead of the relation
1038  * attnames.  (NB: this usage is deprecated since it may result in
1039  * creation of unnecessary transient record types.)
1040  *
1041  * If the type is a base type, a single item alias List is required.
1042  */
1043 TupleDesc
1044 TypeGetTupleDesc(Oid typeoid, List *colaliases)
1045 {
1046         TypeFuncClass functypclass = get_type_func_class(typeoid);
1047         TupleDesc       tupdesc = NULL;
1048
1049         /*
1050          * Build a suitable tupledesc representing the output rows
1051          */
1052         if (functypclass == TYPEFUNC_COMPOSITE)
1053         {
1054                 /* Composite data type, e.g. a table's row type */
1055                 tupdesc = lookup_rowtype_tupdesc_copy(typeoid, -1);
1056
1057                 if (colaliases != NIL)
1058                 {
1059                         int                     natts = tupdesc->natts;
1060                         int                     varattno;
1061
1062                         /* does the list length match the number of attributes? */
1063                         if (list_length(colaliases) != natts)
1064                                 ereport(ERROR,
1065                                                 (errcode(ERRCODE_DATATYPE_MISMATCH),
1066                                                  errmsg("number of aliases does not match number of columns")));
1067
1068                         /* OK, use the aliases instead */
1069                         for (varattno = 0; varattno < natts; varattno++)
1070                         {
1071                                 char       *label = strVal(list_nth(colaliases, varattno));
1072
1073                                 if (label != NULL)
1074                                         namestrcpy(&(tupdesc->attrs[varattno]->attname), label);
1075                         }
1076
1077                         /* The tuple type is now an anonymous record type */
1078                         tupdesc->tdtypeid = RECORDOID;
1079                         tupdesc->tdtypmod = -1;
1080                 }
1081         }
1082         else if (functypclass == TYPEFUNC_SCALAR)
1083         {
1084                 /* Base data type, i.e. scalar */
1085                 char       *attname;
1086
1087                 /* the alias list is required for base types */
1088                 if (colaliases == NIL)
1089                         ereport(ERROR,
1090                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
1091                                          errmsg("no column alias was provided")));
1092
1093                 /* the alias list length must be 1 */
1094                 if (list_length(colaliases) != 1)
1095                         ereport(ERROR,
1096                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
1097                           errmsg("number of aliases does not match number of columns")));
1098
1099                 /* OK, get the column alias */
1100                 attname = strVal(linitial(colaliases));
1101
1102                 tupdesc = CreateTemplateTupleDesc(1, false);
1103                 TupleDescInitEntry(tupdesc,
1104                                                    (AttrNumber) 1,
1105                                                    attname,
1106                                                    typeoid,
1107                                                    -1,
1108                                                    0);
1109         }
1110         else if (functypclass == TYPEFUNC_RECORD)
1111         {
1112                 /* XXX can't support this because typmod wasn't passed in ... */
1113                 ereport(ERROR,
1114                                 (errcode(ERRCODE_DATATYPE_MISMATCH),
1115                                  errmsg("could not determine row description for function returning record")));
1116         }
1117         else
1118         {
1119                 /* crummy error message, but parser should have caught this */
1120                 elog(ERROR, "function in FROM has unsupported return type");
1121         }
1122
1123         return tupdesc;
1124 }