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) 2002-2008, PostgreSQL Global Development Group
   8  *
   9  * IDENTIFICATION
  10  *        $PostgreSQL: pgsql/src/backend/utils/fmgr/funcapi.c,v 1.37 2008/01/01 19:45:53 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 cannot 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 polymorphic pseudotypes (ANYELEMENT etc), either
 197  * as a scalar result 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 (IsPolymorphicType(rettype))
 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 etc) with correct data types
 393  * deduced from the input arguments. Returns TRUE if able to deduce all types,
 394  * 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         bool            have_anynonarray = false;
 405         bool            have_anyenum = false;
 406         Oid                     anyelement_type = InvalidOid;
 407         Oid                     anyarray_type = InvalidOid;
 408         int                     i;
 409
 410         /* See if there are any polymorphic outputs; quick out if not */
 411         for (i = 0; i < natts; i++)
 412         {
 413                 switch (tupdesc->attrs[i]->atttypid)
 414                 {
 415                         case ANYELEMENTOID:
 416                                 have_anyelement_result = true;
 417                                 break;
 418                         case ANYARRAYOID:
 419                                 have_anyarray_result = true;
 420                                 break;
 421                         case ANYNONARRAYOID:
 422                                 have_anyelement_result = true;
 423                                 have_anynonarray = true;
 424                                 break;
 425                         case ANYENUMOID:
 426                                 have_anyelement_result = true;
 427                                 have_anyenum = true;
 428                                 break;
 429                         default:
 430                                 break;
 431                 }
 432         }
 433         if (!have_anyelement_result && !have_anyarray_result)
 434                 return true;
 435
 436         /*
 437          * Otherwise, extract actual datatype(s) from input arguments.  (We assume
 438          * the parser already validated consistency of the arguments.)
 439          */
 440         if (!call_expr)
 441                 return false;                   /* no hope */
 442
 443         for (i = 0; i < nargs; i++)
 444         {
 445                 switch (declared_args->values[i])
 446                 {
 447                         case ANYELEMENTOID:
 448                         case ANYNONARRAYOID:
 449                         case ANYENUMOID:
 450                                 if (!OidIsValid(anyelement_type))
 451                                         anyelement_type = get_call_expr_argtype(call_expr, i);
 452                                 break;
 453                         case ANYARRAYOID:
 454                                 if (!OidIsValid(anyarray_type))
 455                                         anyarray_type = get_call_expr_argtype(call_expr, i);
 456                                 break;
 457                         default:
 458                                 break;
 459                 }
 460         }
 461
 462         /* If nothing found, parser messed up */
 463         if (!OidIsValid(anyelement_type) && !OidIsValid(anyarray_type))
 464                 return false;
 465
 466         /* If needed, deduce one polymorphic type from the other */
 467         if (have_anyelement_result && !OidIsValid(anyelement_type))
 468                 anyelement_type = resolve_generic_type(ANYELEMENTOID,
 469                                                                                            anyarray_type,
 470                                                                                            ANYARRAYOID);
 471         if (have_anyarray_result && !OidIsValid(anyarray_type))
 472                 anyarray_type = resolve_generic_type(ANYARRAYOID,
 473                                                                                          anyelement_type,
 474                                                                                          ANYELEMENTOID);
 475
 476         /* Enforce ANYNONARRAY if needed */
 477         if (have_anynonarray && type_is_array(anyelement_type))
 478                 return false;
 479
 480         /* Enforce ANYENUM if needed */
 481         if (have_anyenum && !type_is_enum(anyelement_type))
 482                 return false;
 483
 484         /* And finally replace the tuple column types as needed */
 485         for (i = 0; i < natts; i++)
 486         {
 487                 switch (tupdesc->attrs[i]->atttypid)
 488                 {
 489                         case ANYELEMENTOID:
 490                         case ANYNONARRAYOID:
 491                         case ANYENUMOID:
 492                                 TupleDescInitEntry(tupdesc, i + 1,
 493                                                                    NameStr(tupdesc->attrs[i]->attname),
 494                                                                    anyelement_type,
 495                                                                    -1,
 496                                                                    0);
 497                                 break;
 498                         case ANYARRAYOID:
 499                                 TupleDescInitEntry(tupdesc, i + 1,
 500                                                                    NameStr(tupdesc->attrs[i]->attname),
 501                                                                    anyarray_type,
 502                                                                    -1,
 503                                                                    0);
 504                                 break;
 505                         default:
 506                                 break;
 507                 }
 508         }
 509
 510         return true;
 511 }
 512
 513 /*
 514  * Given the declared argument types and modes for a function, replace any
 515  * polymorphic types (ANYELEMENT etc) with correct data types deduced from the
 516  * input arguments.  Returns TRUE if able to deduce all types, FALSE if not.
 517  * This is the same logic as resolve_polymorphic_tupdesc, but with a different
 518  * argument representation.
 519  *
 520  * argmodes may be NULL, in which case all arguments are assumed to be IN mode.
 521  */
 522 bool
 523 resolve_polymorphic_argtypes(int numargs, Oid *argtypes, char *argmodes,
 524                                                          Node *call_expr)
 525 {
 526         bool            have_anyelement_result = false;
 527         bool            have_anyarray_result = false;
 528         Oid                     anyelement_type = InvalidOid;
 529         Oid                     anyarray_type = InvalidOid;
 530         int                     inargno;
 531         int                     i;
 532
 533         /* First pass: resolve polymorphic inputs, check for outputs */
 534         inargno = 0;
 535         for (i = 0; i < numargs; i++)
 536         {
 537                 char            argmode = argmodes ? argmodes[i] : PROARGMODE_IN;
 538
 539                 switch (argtypes[i])
 540                 {
 541                         case ANYELEMENTOID:
 542                         case ANYNONARRAYOID:
 543                         case ANYENUMOID:
 544                                 if (argmode == PROARGMODE_OUT)
 545                                         have_anyelement_result = true;
 546                                 else
 547                                 {
 548                                         if (!OidIsValid(anyelement_type))
 549                                         {
 550                                                 anyelement_type = get_call_expr_argtype(call_expr,
 551                                                                                                                                 inargno);
 552                                                 if (!OidIsValid(anyelement_type))
 553                                                         return false;
 554                                         }
 555                                         argtypes[i] = anyelement_type;
 556                                 }
 557                                 break;
 558                         case ANYARRAYOID:
 559                                 if (argmode == PROARGMODE_OUT)
 560                                         have_anyarray_result = true;
 561                                 else
 562                                 {
 563                                         if (!OidIsValid(anyarray_type))
 564                                         {
 565                                                 anyarray_type = get_call_expr_argtype(call_expr,
 566                                                                                                                           inargno);
 567                                                 if (!OidIsValid(anyarray_type))
 568                                                         return false;
 569                                         }
 570                                         argtypes[i] = anyarray_type;
 571                                 }
 572                                 break;
 573                         default:
 574                                 break;
 575                 }
 576                 if (argmode != PROARGMODE_OUT)
 577                         inargno++;
 578         }
 579
 580         /* Done? */
 581         if (!have_anyelement_result && !have_anyarray_result)
 582                 return true;
 583
 584         /* If no input polymorphics, parser messed up */
 585         if (!OidIsValid(anyelement_type) && !OidIsValid(anyarray_type))
 586                 return false;
 587
 588         /* If needed, deduce one polymorphic type from the other */
 589         if (have_anyelement_result && !OidIsValid(anyelement_type))
 590                 anyelement_type = resolve_generic_type(ANYELEMENTOID,
 591                                                                                            anyarray_type,
 592                                                                                            ANYARRAYOID);
 593         if (have_anyarray_result && !OidIsValid(anyarray_type))
 594                 anyarray_type = resolve_generic_type(ANYARRAYOID,
 595                                                                                          anyelement_type,
 596                                                                                          ANYELEMENTOID);
 597
 598         /* XXX do we need to enforce ANYNONARRAY or ANYENUM here?  I think not */
 599
 600         /* And finally replace the output column types as needed */
 601         for (i = 0; i < numargs; i++)
 602         {
 603                 switch (argtypes[i])
 604                 {
 605                         case ANYELEMENTOID:
 606                         case ANYNONARRAYOID:
 607                         case ANYENUMOID:
 608                                 argtypes[i] = anyelement_type;
 609                                 break;
 610                         case ANYARRAYOID:
 611                                 argtypes[i] = anyarray_type;
 612                                 break;
 613                         default:
 614                                 break;
 615                 }
 616         }
 617
 618         return true;
 619 }
 620
 621 /*
 622  * get_type_func_class
 623  *              Given the type OID, obtain its TYPEFUNC classification.
 624  *
 625  * This is intended to centralize a bunch of formerly ad-hoc code for
 626  * classifying types.  The categories used here are useful for deciding
 627  * how to handle functions returning the datatype.
 628  */
 629 static TypeFuncClass
 630 get_type_func_class(Oid typid)
 631 {
 632         switch (get_typtype(typid))
 633         {
 634                 case TYPTYPE_COMPOSITE:
 635                         return TYPEFUNC_COMPOSITE;
 636                 case TYPTYPE_BASE:
 637                 case TYPTYPE_DOMAIN:
 638                 case TYPTYPE_ENUM:
 639                         return TYPEFUNC_SCALAR;
 640                 case TYPTYPE_PSEUDO:
 641                         if (typid == RECORDOID)
 642                                 return TYPEFUNC_RECORD;
 643
 644                         /*
 645                          * We treat VOID and CSTRING as legitimate scalar datatypes,
 646                          * mostly for the convenience of the JDBC driver (which wants to
 647                          * be able to do "SELECT * FROM foo()" for all legitimately
 648                          * user-callable functions).
 649                          */
 650                         if (typid == VOIDOID || typid == CSTRINGOID)
 651                                 return TYPEFUNC_SCALAR;
 652                         return TYPEFUNC_OTHER;
 653         }
 654         /* shouldn't get here, probably */
 655         return TYPEFUNC_OTHER;
 656 }
 657
 658
 659 /*
 660  * get_func_arg_info
 661  *
 662  * Fetch info about the argument types, names, and IN/OUT modes from the
 663  * pg_proc tuple.  Return value is the total number of arguments.
 664  * Other results are palloc'd.  *p_argtypes is always filled in, but
 665  * *p_argnames and *p_argmodes will be set NULL in the default cases
 666  * (no names, and all IN arguments, respectively).
 667  *
 668  * Note that this function simply fetches what is in the pg_proc tuple;
 669  * it doesn't do any interpretation of polymorphic types.
 670  */
 671 int
 672 get_func_arg_info(HeapTuple procTup,
 673                                   Oid **p_argtypes, char ***p_argnames, char **p_argmodes)
 674 {
 675         Form_pg_proc procStruct = (Form_pg_proc) GETSTRUCT(procTup);
 676         Datum           proallargtypes;
 677         Datum           proargmodes;
 678         Datum           proargnames;
 679         bool            isNull;
 680         ArrayType  *arr;
 681         int                     numargs;
 682         Datum      *elems;
 683         int                     nelems;
 684         int                     i;
 685
 686         /* First discover the total number of parameters and get their types */
 687         proallargtypes = SysCacheGetAttr(PROCOID, procTup,
 688                                                                          Anum_pg_proc_proallargtypes,
 689                                                                          &isNull);
 690         if (!isNull)
 691         {
 692                 /*
 693                  * We expect the arrays to be 1-D arrays of the right types; verify
 694                  * that.  For the OID and char arrays, we don't need to use
 695                  * deconstruct_array() since the array data is just going to look like
 696                  * a C array of values.
 697                  */
 698                 arr = DatumGetArrayTypeP(proallargtypes);               /* ensure not toasted */
 699                 numargs = ARR_DIMS(arr)[0];
 700                 if (ARR_NDIM(arr) != 1 ||
 701                         numargs < 0 ||
 702                         ARR_HASNULL(arr) ||
 703                         ARR_ELEMTYPE(arr) != OIDOID)
 704                         elog(ERROR, "proallargtypes is not a 1-D Oid array");
 705                 Assert(numargs >= procStruct->pronargs);
 706                 *p_argtypes = (Oid *) palloc(numargs * sizeof(Oid));
 707                 memcpy(*p_argtypes, ARR_DATA_PTR(arr),
 708                            numargs * sizeof(Oid));
 709         }
 710         else
 711         {
 712                 /* If no proallargtypes, use proargtypes */
 713                 numargs = procStruct->proargtypes.dim1;
 714                 Assert(numargs == procStruct->pronargs);
 715                 *p_argtypes = (Oid *) palloc(numargs * sizeof(Oid));
 716                 memcpy(*p_argtypes, procStruct->proargtypes.values,
 717                            numargs * sizeof(Oid));
 718         }
 719
 720         /* Get argument names, if available */
 721         proargnames = SysCacheGetAttr(PROCOID, procTup,
 722                                                                   Anum_pg_proc_proargnames,
 723                                                                   &isNull);
 724         if (isNull)
 725                 *p_argnames = NULL;
 726         else
 727         {
 728                 deconstruct_array(DatumGetArrayTypeP(proargnames),
 729                                                   TEXTOID, -1, false, 'i',
 730                                                   &elems, NULL, &nelems);
 731                 if (nelems != numargs)  /* should not happen */
 732                         elog(ERROR, "proargnames must have the same number of elements as the function has arguments");
 733                 *p_argnames = (char **) palloc(sizeof(char *) * numargs);
 734                 for (i = 0; i < numargs; i++)
 735                         (*p_argnames)[i] = DatumGetCString(DirectFunctionCall1(textout,
 736                                                                                                                                    elems[i]));
 737         }
 738
 739         /* Get argument modes, if available */
 740         proargmodes = SysCacheGetAttr(PROCOID, procTup,
 741                                                                   Anum_pg_proc_proargmodes,
 742                                                                   &isNull);
 743         if (isNull)
 744                 *p_argmodes = NULL;
 745         else
 746         {
 747                 arr = DatumGetArrayTypeP(proargmodes);  /* ensure not toasted */
 748                 if (ARR_NDIM(arr) != 1 ||
 749                         ARR_DIMS(arr)[0] != numargs ||
 750                         ARR_HASNULL(arr) ||
 751                         ARR_ELEMTYPE(arr) != CHAROID)
 752                         elog(ERROR, "proargmodes is not a 1-D char array");
 753                 *p_argmodes = (char *) palloc(numargs * sizeof(char));
 754                 memcpy(*p_argmodes, ARR_DATA_PTR(arr),
 755                            numargs * sizeof(char));
 756         }
 757
 758         return numargs;
 759 }
 760
 761
 762 /*
 763  * get_func_result_name
 764  *
 765  * If the function has exactly one output parameter, and that parameter
 766  * is named, return the name (as a palloc'd string).  Else return NULL.
 767  *
 768  * This is used to determine the default output column name for functions
 769  * returning scalar types.
 770  */
 771 char *
 772 get_func_result_name(Oid functionId)
 773 {
 774         char       *result;
 775         HeapTuple       procTuple;
 776         Datum           proargmodes;
 777         Datum           proargnames;
 778         bool            isnull;
 779         ArrayType  *arr;
 780         int                     numargs;
 781         char       *argmodes;
 782         Datum      *argnames;
 783         int                     numoutargs;
 784         int                     nargnames;
 785         int                     i;
 786
 787         /* First fetch the function's pg_proc row */
 788         procTuple = SearchSysCache(PROCOID,
 789                                                            ObjectIdGetDatum(functionId),
 790                                                            0, 0, 0);
 791         if (!HeapTupleIsValid(procTuple))
 792                 elog(ERROR, "cache lookup failed for function %u", functionId);
 793
 794         /* If there are no named OUT parameters, return NULL */
 795         if (heap_attisnull(procTuple, Anum_pg_proc_proargmodes) ||
 796                 heap_attisnull(procTuple, Anum_pg_proc_proargnames))
 797                 result = NULL;
 798         else
 799         {
 800                 /* Get the data out of the tuple */
 801                 proargmodes = SysCacheGetAttr(PROCOID, procTuple,
 802                                                                           Anum_pg_proc_proargmodes,
 803                                                                           &isnull);
 804                 Assert(!isnull);
 805                 proargnames = SysCacheGetAttr(PROCOID, procTuple,
 806                                                                           Anum_pg_proc_proargnames,
 807                                                                           &isnull);
 808                 Assert(!isnull);
 809
 810                 /*
 811                  * We expect the arrays to be 1-D arrays of the right types; verify
 812                  * that.  For the char array, we don't need to use deconstruct_array()
 813                  * since the array data is just going to look like a C array of
 814                  * values.
 815                  */
 816                 arr = DatumGetArrayTypeP(proargmodes);  /* ensure not toasted */
 817                 numargs = ARR_DIMS(arr)[0];
 818                 if (ARR_NDIM(arr) != 1 ||
 819                         numargs < 0 ||
 820                         ARR_HASNULL(arr) ||
 821                         ARR_ELEMTYPE(arr) != CHAROID)
 822                         elog(ERROR, "proargmodes is not a 1-D char array");
 823                 argmodes = (char *) ARR_DATA_PTR(arr);
 824                 arr = DatumGetArrayTypeP(proargnames);  /* ensure not toasted */
 825                 if (ARR_NDIM(arr) != 1 ||
 826                         ARR_DIMS(arr)[0] != numargs ||
 827                         ARR_HASNULL(arr) ||
 828                         ARR_ELEMTYPE(arr) != TEXTOID)
 829                         elog(ERROR, "proargnames is not a 1-D text array");
 830                 deconstruct_array(arr, TEXTOID, -1, false, 'i',
 831                                                   &argnames, NULL, &nargnames);
 832                 Assert(nargnames == numargs);
 833
 834                 /* scan for output argument(s) */
 835                 result = NULL;
 836                 numoutargs = 0;
 837                 for (i = 0; i < numargs; i++)
 838                 {
 839                         if (argmodes[i] == PROARGMODE_IN)
 840                                 continue;
 841                         Assert(argmodes[i] == PROARGMODE_OUT ||
 842                                    argmodes[i] == PROARGMODE_INOUT);
 843                         if (++numoutargs > 1)
 844                         {
 845                                 /* multiple out args, so forget it */
 846                                 result = NULL;
 847                                 break;
 848                         }
 849                         result = DatumGetCString(DirectFunctionCall1(textout,
 850                                                                                                                  argnames[i]));
 851                         if (result == NULL || result[0] == '\0')
 852                         {
 853                                 /* Parameter is not named, so forget it */
 854                                 result = NULL;
 855                                 break;
 856                         }
 857                 }
 858         }
 859
 860         ReleaseSysCache(procTuple);
 861
 862         return result;
 863 }
 864
 865
 866 /*
 867  * build_function_result_tupdesc_t
 868  *
 869  * Given a pg_proc row for a function, return a tuple descriptor for the
 870  * result rowtype, or NULL if the function does not have OUT parameters.
 871  *
 872  * Note that this does not handle resolution of polymorphic types;
 873  * that is deliberate.
 874  */
 875 TupleDesc
 876 build_function_result_tupdesc_t(HeapTuple procTuple)
 877 {
 878         Form_pg_proc procform = (Form_pg_proc) GETSTRUCT(procTuple);
 879         Datum           proallargtypes;
 880         Datum           proargmodes;
 881         Datum           proargnames;
 882         bool            isnull;
 883
 884         /* Return NULL if the function isn't declared to return RECORD */
 885         if (procform->prorettype != RECORDOID)
 886                 return NULL;
 887
 888         /* If there are no OUT parameters, return NULL */
 889         if (heap_attisnull(procTuple, Anum_pg_proc_proallargtypes) ||
 890                 heap_attisnull(procTuple, Anum_pg_proc_proargmodes))
 891                 return NULL;
 892
 893         /* Get the data out of the tuple */
 894         proallargtypes = SysCacheGetAttr(PROCOID, procTuple,
 895                                                                          Anum_pg_proc_proallargtypes,
 896                                                                          &isnull);
 897         Assert(!isnull);
 898         proargmodes = SysCacheGetAttr(PROCOID, procTuple,
 899                                                                   Anum_pg_proc_proargmodes,
 900                                                                   &isnull);
 901         Assert(!isnull);
 902         proargnames = SysCacheGetAttr(PROCOID, procTuple,
 903                                                                   Anum_pg_proc_proargnames,
 904                                                                   &isnull);
 905         if (isnull)
 906                 proargnames = PointerGetDatum(NULL);    /* just to be sure */
 907
 908         return build_function_result_tupdesc_d(proallargtypes,
 909                                                                                    proargmodes,
 910                                                                                    proargnames);
 911 }
 912
 913 /*
 914  * build_function_result_tupdesc_d
 915  *
 916  * Build a RECORD function's tupledesc from the pg_proc proallargtypes,
 917  * proargmodes, and proargnames arrays.  This is split out for the
 918  * convenience of ProcedureCreate, which needs to be able to compute the
 919  * tupledesc before actually creating the function.
 920  *
 921  * Returns NULL if there are not at least two OUT or INOUT arguments.
 922  */
 923 TupleDesc
 924 build_function_result_tupdesc_d(Datum proallargtypes,
 925                                                                 Datum proargmodes,
 926                                                                 Datum proargnames)
 927 {
 928         TupleDesc       desc;
 929         ArrayType  *arr;
 930         int                     numargs;
 931         Oid                *argtypes;
 932         char       *argmodes;
 933         Datum      *argnames = NULL;
 934         Oid                *outargtypes;
 935         char      **outargnames;
 936         int                     numoutargs;
 937         int                     nargnames;
 938         int                     i;
 939
 940         /* Can't have output args if columns are null */
 941         if (proallargtypes == PointerGetDatum(NULL) ||
 942                 proargmodes == PointerGetDatum(NULL))
 943                 return NULL;
 944
 945         /*
 946          * We expect the arrays to be 1-D arrays of the right types; verify that.
 947          * For the OID and char arrays, we don't need to use deconstruct_array()
 948          * since the array data is just going to look like a C array of values.
 949          */
 950         arr = DatumGetArrayTypeP(proallargtypes);       /* ensure not toasted */
 951         numargs = ARR_DIMS(arr)[0];
 952         if (ARR_NDIM(arr) != 1 ||
 953                 numargs < 0 ||
 954                 ARR_HASNULL(arr) ||
 955                 ARR_ELEMTYPE(arr) != OIDOID)
 956                 elog(ERROR, "proallargtypes is not a 1-D Oid array");
 957         argtypes = (Oid *) ARR_DATA_PTR(arr);
 958         arr = DatumGetArrayTypeP(proargmodes);          /* ensure not toasted */
 959         if (ARR_NDIM(arr) != 1 ||
 960                 ARR_DIMS(arr)[0] != numargs ||
 961                 ARR_HASNULL(arr) ||
 962                 ARR_ELEMTYPE(arr) != CHAROID)
 963                 elog(ERROR, "proargmodes is not a 1-D char array");
 964         argmodes = (char *) ARR_DATA_PTR(arr);
 965         if (proargnames != PointerGetDatum(NULL))
 966         {
 967                 arr = DatumGetArrayTypeP(proargnames);  /* ensure not toasted */
 968                 if (ARR_NDIM(arr) != 1 ||
 969                         ARR_DIMS(arr)[0] != numargs ||
 970                         ARR_HASNULL(arr) ||
 971                         ARR_ELEMTYPE(arr) != TEXTOID)
 972                         elog(ERROR, "proargnames is not a 1-D text array");
 973                 deconstruct_array(arr, TEXTOID, -1, false, 'i',
 974                                                   &argnames, NULL, &nargnames);
 975                 Assert(nargnames == numargs);
 976         }
 977
 978         /* zero elements probably shouldn't happen, but handle it gracefully */
 979         if (numargs <= 0)
 980                 return NULL;
 981
 982         /* extract output-argument types and names */
 983         outargtypes = (Oid *) palloc(numargs * sizeof(Oid));
 984         outargnames = (char **) palloc(numargs * sizeof(char *));
 985         numoutargs = 0;
 986         for (i = 0; i < numargs; i++)
 987         {
 988                 char       *pname;
 989
 990                 if (argmodes[i] == PROARGMODE_IN)
 991                         continue;
 992                 Assert(argmodes[i] == PROARGMODE_OUT ||
 993                            argmodes[i] == PROARGMODE_INOUT);
 994                 outargtypes[numoutargs] = argtypes[i];
 995                 if (argnames)
 996                         pname = DatumGetCString(DirectFunctionCall1(textout, argnames[i]));
 997                 else
 998                         pname = NULL;
 999                 if (pname == NULL || pname[0] == '\0')
1000                 {
1001                         /* Parameter is not named, so gin up a column name */
1002                         pname = (char *) palloc(32);
1003                         snprintf(pname, 32, "column%d", numoutargs + 1);
1004                 }
1005                 outargnames[numoutargs] = pname;
1006                 numoutargs++;
1007         }
1008
1009         /*
1010          * If there is no output argument, or only one, the function does not
1011          * return tuples.
1012          */
1013         if (numoutargs < 2)
1014                 return NULL;
1015
1016         desc = CreateTemplateTupleDesc(numoutargs, false);
1017         for (i = 0; i < numoutargs; i++)
1018         {
1019                 TupleDescInitEntry(desc, i + 1,
1020                                                    outargnames[i],
1021                                                    outargtypes[i],
1022                                                    -1,
1023                                                    0);
1024         }
1025
1026         return desc;
1027 }
1028
1029
1030 /*
1031  * RelationNameGetTupleDesc
1032  *
1033  * Given a (possibly qualified) relation name, build a TupleDesc.
1034  *
1035  * Note: while this works as advertised, it's seldom the best way to
1036  * build a tupdesc for a function's result type.  It's kept around
1037  * only for backwards compatibility with existing user-written code.
1038  */
1039 TupleDesc
1040 RelationNameGetTupleDesc(const char *relname)
1041 {
1042         RangeVar   *relvar;
1043         Relation        rel;
1044         TupleDesc       tupdesc;
1045         List       *relname_list;
1046
1047         /* Open relation and copy the tuple description */
1048         relname_list = stringToQualifiedNameList(relname);
1049         relvar = makeRangeVarFromNameList(relname_list);
1050         rel = relation_openrv(relvar, AccessShareLock);
1051         tupdesc = CreateTupleDescCopy(RelationGetDescr(rel));
1052         relation_close(rel, AccessShareLock);
1053
1054         return tupdesc;
1055 }
1056
1057 /*
1058  * TypeGetTupleDesc
1059  *
1060  * Given a type Oid, build a TupleDesc.  (In most cases you should be
1061  * using get_call_result_type or one of its siblings instead of this
1062  * routine, so that you can handle OUT parameters, RECORD result type,
1063  * and polymorphic results.)
1064  *
1065  * If the type is composite, *and* a colaliases List is provided, *and*
1066  * the List is of natts length, use the aliases instead of the relation
1067  * attnames.  (NB: this usage is deprecated since it may result in
1068  * creation of unnecessary transient record types.)
1069  *
1070  * If the type is a base type, a single item alias List is required.
1071  */
1072 TupleDesc
1073 TypeGetTupleDesc(Oid typeoid, List *colaliases)
1074 {
1075         TypeFuncClass functypclass = get_type_func_class(typeoid);
1076         TupleDesc       tupdesc = NULL;
1077
1078         /*
1079          * Build a suitable tupledesc representing the output rows
1080          */
1081         if (functypclass == TYPEFUNC_COMPOSITE)
1082         {
1083                 /* Composite data type, e.g. a table's row type */
1084                 tupdesc = lookup_rowtype_tupdesc_copy(typeoid, -1);
1085
1086                 if (colaliases != NIL)
1087                 {
1088                         int                     natts = tupdesc->natts;
1089                         int                     varattno;
1090
1091                         /* does the list length match the number of attributes? */
1092                         if (list_length(colaliases) != natts)
1093                                 ereport(ERROR,
1094                                                 (errcode(ERRCODE_DATATYPE_MISMATCH),
1095                                                  errmsg("number of aliases does not match number of columns")));
1096
1097                         /* OK, use the aliases instead */
1098                         for (varattno = 0; varattno < natts; varattno++)
1099                         {
1100                                 char       *label = strVal(list_nth(colaliases, varattno));
1101
1102                                 if (label != NULL)
1103                                         namestrcpy(&(tupdesc->attrs[varattno]->attname), label);
1104                         }
1105
1106                         /* The tuple type is now an anonymous record type */
1107                         tupdesc->tdtypeid = RECORDOID;
1108                         tupdesc->tdtypmod = -1;
1109                 }
1110         }
1111         else if (functypclass == TYPEFUNC_SCALAR)
1112         {
1113                 /* Base data type, i.e. scalar */
1114                 char       *attname;
1115
1116                 /* the alias list is required for base types */
1117                 if (colaliases == NIL)
1118                         ereport(ERROR,
1119                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
1120                                          errmsg("no column alias was provided")));
1121
1122                 /* the alias list length must be 1 */
1123                 if (list_length(colaliases) != 1)
1124                         ereport(ERROR,
1125                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
1126                           errmsg("number of aliases does not match number of columns")));
1127
1128                 /* OK, get the column alias */
1129                 attname = strVal(linitial(colaliases));
1130
1131                 tupdesc = CreateTemplateTupleDesc(1, false);
1132                 TupleDescInitEntry(tupdesc,
1133                                                    (AttrNumber) 1,
1134                                                    attname,
1135                                                    typeoid,
1136                                                    -1,
1137                                                    0);
1138         }
1139         else if (functypclass == TYPEFUNC_RECORD)
1140         {
1141                 /* XXX can't support this because typmod wasn't passed in ... */
1142                 ereport(ERROR,
1143                                 (errcode(ERRCODE_DATATYPE_MISMATCH),
1144                                  errmsg("could not determine row description for function returning record")));
1145         }
1146         else
1147         {
1148                 /* crummy error message, but parser should have caught this */
1149                 elog(ERROR, "function in FROM has unsupported return type");
1150         }
1151
1152         return tupdesc;
1153 }