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) 2002-2009, PostgreSQL Global Development Group
   8  *
   9  * IDENTIFICATION
  10  *        $PostgreSQL: pgsql/src/backend/utils/fmgr/funcapi.c,v 1.45 2009/06/11 14:49:05 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 "nodes/nodeFuncs.h"
  22 #include "parser/parse_coerce.h"
  23 #include "utils/array.h"
  24 #include "utils/builtins.h"
  25 #include "utils/lsyscache.h"
  26 #include "utils/memutils.h"
  27 #include "utils/syscache.h"
  28 #include "utils/typcache.h"
  29
  30
  31 static void shutdown_MultiFuncCall(Datum arg);
  32 static TypeFuncClass internal_get_result_type(Oid funcid,
  33                                                  Node *call_expr,
  34                                                  ReturnSetInfo *rsinfo,
  35                                                  Oid *resultTypeId,
  36                                                  TupleDesc *resultTupleDesc);
  37 static bool resolve_polymorphic_tupdesc(TupleDesc tupdesc,
  38                                                         oidvector *declared_args,
  39                                                         Node *call_expr);
  40 static TypeFuncClass get_type_func_class(Oid typid);
  41
  42
  43 /*
  44  * init_MultiFuncCall
  45  * Create an empty FuncCallContext data structure
  46  * and do some other basic Multi-function call setup
  47  * and error checking
  48  */
  49 FuncCallContext *
  50 init_MultiFuncCall(PG_FUNCTION_ARGS)
  51 {
  52         FuncCallContext *retval;
  53
  54         /*
  55          * Bail if we're called in the wrong context
  56          */
  57         if (fcinfo->resultinfo == NULL || !IsA(fcinfo->resultinfo, ReturnSetInfo))
  58                 ereport(ERROR,
  59                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
  60                                  errmsg("set-valued function called in context that cannot accept a set")));
  61
  62         if (fcinfo->flinfo->fn_extra == NULL)
  63         {
  64                 /*
  65                  * First call
  66                  */
  67                 ReturnSetInfo *rsi = (ReturnSetInfo *) fcinfo->resultinfo;
  68                 MemoryContext multi_call_ctx;
  69
  70                 /*
  71                  * Create a suitably long-lived context to hold cross-call data
  72                  */
  73                 multi_call_ctx = AllocSetContextCreate(fcinfo->flinfo->fn_mcxt,
  74                                                                                            "SRF multi-call context",
  75                                                                                            ALLOCSET_SMALL_MINSIZE,
  76                                                                                            ALLOCSET_SMALL_INITSIZE,
  77                                                                                            ALLOCSET_SMALL_MAXSIZE);
  78
  79                 /*
  80                  * Allocate suitably long-lived space and zero it
  81                  */
  82                 retval = (FuncCallContext *)
  83                         MemoryContextAllocZero(multi_call_ctx,
  84                                                                    sizeof(FuncCallContext));
  85
  86                 /*
  87                  * initialize the elements
  88                  */
  89                 retval->call_cntr = 0;
  90                 retval->max_calls = 0;
  91                 retval->slot = NULL;
  92                 retval->user_fctx = NULL;
  93                 retval->attinmeta = NULL;
  94                 retval->tuple_desc = NULL;
  95                 retval->multi_call_memory_ctx = multi_call_ctx;
  96
  97                 /*
  98                  * save the pointer for cross-call use
  99                  */
 100                 fcinfo->flinfo->fn_extra = retval;
 101
 102                 /*
 103                  * Ensure we will get shut down cleanly if the exprcontext is not run
 104                  * to completion.
 105                  */
 106                 RegisterExprContextCallback(rsi->econtext,
 107                                                                         shutdown_MultiFuncCall,
 108                                                                         PointerGetDatum(fcinfo->flinfo));
 109         }
 110         else
 111         {
 112                 /* second and subsequent calls */
 113                 elog(ERROR, "init_MultiFuncCall cannot be called more than once");
 114
 115                 /* never reached, but keep compiler happy */
 116                 retval = NULL;
 117         }
 118
 119         return retval;
 120 }
 121
 122 /*
 123  * per_MultiFuncCall
 124  *
 125  * Do Multi-function per-call setup
 126  */
 127 FuncCallContext *
 128 per_MultiFuncCall(PG_FUNCTION_ARGS)
 129 {
 130         FuncCallContext *retval = (FuncCallContext *) fcinfo->flinfo->fn_extra;
 131
 132         /*
 133          * Clear the TupleTableSlot, if present.  This is for safety's sake: the
 134          * Slot will be in a long-lived context (it better be, if the
 135          * FuncCallContext is pointing to it), but in most usage patterns the
 136          * tuples stored in it will be in the function's per-tuple context. So at
 137          * the beginning of each call, the Slot will hold a dangling pointer to an
 138          * already-recycled tuple.      We clear it out here.
 139          *
 140          * Note: use of retval->slot is obsolete as of 8.0, and we expect that it
 141          * will always be NULL.  This is just here for backwards compatibility in
 142          * case someone creates a slot anyway.
 143          */
 144         if (retval->slot != NULL)
 145                 ExecClearTuple(retval->slot);
 146
 147         return retval;
 148 }
 149
 150 /*
 151  * end_MultiFuncCall
 152  * Clean up after init_MultiFuncCall
 153  */
 154 void
 155 end_MultiFuncCall(PG_FUNCTION_ARGS, FuncCallContext *funcctx)
 156 {
 157         ReturnSetInfo *rsi = (ReturnSetInfo *) fcinfo->resultinfo;
 158
 159         /* Deregister the shutdown callback */
 160         UnregisterExprContextCallback(rsi->econtext,
 161                                                                   shutdown_MultiFuncCall,
 162                                                                   PointerGetDatum(fcinfo->flinfo));
 163
 164         /* But use it to do the real work */
 165         shutdown_MultiFuncCall(PointerGetDatum(fcinfo->flinfo));
 166 }
 167
 168 /*
 169  * shutdown_MultiFuncCall
 170  * Shutdown function to clean up after init_MultiFuncCall
 171  */
 172 static void
 173 shutdown_MultiFuncCall(Datum arg)
 174 {
 175         FmgrInfo   *flinfo = (FmgrInfo *) DatumGetPointer(arg);
 176         FuncCallContext *funcctx = (FuncCallContext *) flinfo->fn_extra;
 177
 178         /* unbind from flinfo */
 179         flinfo->fn_extra = NULL;
 180
 181         /*
 182          * Delete context that holds all multi-call data, including the
 183          * FuncCallContext itself
 184          */
 185         MemoryContextDelete(funcctx->multi_call_memory_ctx);
 186 }
 187
 188
 189 /*
 190  * get_call_result_type
 191  *              Given a function's call info record, determine the kind of datatype
 192  *              it is supposed to return.  If resultTypeId isn't NULL, *resultTypeId
 193  *              receives the actual datatype OID (this is mainly useful for scalar
 194  *              result types).  If resultTupleDesc isn't NULL, *resultTupleDesc
 195  *              receives a pointer to a TupleDesc when the result is of a composite
 196  *              type, or NULL when it's a scalar result.
 197  *
 198  * One hard case that this handles is resolution of actual rowtypes for
 199  * functions returning RECORD (from either the function's OUT parameter
 200  * list, or a ReturnSetInfo context node).      TYPEFUNC_RECORD is returned
 201  * only when we couldn't resolve the actual rowtype for lack of information.
 202  *
 203  * The other hard case that this handles is resolution of polymorphism.
 204  * We will never return polymorphic pseudotypes (ANYELEMENT etc), either
 205  * as a scalar result type or as a component of a rowtype.
 206  *
 207  * This function is relatively expensive --- in a function returning set,
 208  * try to call it only the first time through.
 209  */
 210 TypeFuncClass
 211 get_call_result_type(FunctionCallInfo fcinfo,
 212                                          Oid *resultTypeId,
 213                                          TupleDesc *resultTupleDesc)
 214 {
 215         return internal_get_result_type(fcinfo->flinfo->fn_oid,
 216                                                                         fcinfo->flinfo->fn_expr,
 217                                                                         (ReturnSetInfo *) fcinfo->resultinfo,
 218                                                                         resultTypeId,
 219                                                                         resultTupleDesc);
 220 }
 221
 222 /*
 223  * get_expr_result_type
 224  *              As above, but work from a calling expression node tree
 225  */
 226 TypeFuncClass
 227 get_expr_result_type(Node *expr,
 228                                          Oid *resultTypeId,
 229                                          TupleDesc *resultTupleDesc)
 230 {
 231         TypeFuncClass result;
 232
 233         if (expr && IsA(expr, FuncExpr))
 234                 result = internal_get_result_type(((FuncExpr *) expr)->funcid,
 235                                                                                   expr,
 236                                                                                   NULL,
 237                                                                                   resultTypeId,
 238                                                                                   resultTupleDesc);
 239         else if (expr && IsA(expr, OpExpr))
 240                 result = internal_get_result_type(get_opcode(((OpExpr *) expr)->opno),
 241                                                                                   expr,
 242                                                                                   NULL,
 243                                                                                   resultTypeId,
 244                                                                                   resultTupleDesc);
 245         else
 246         {
 247                 /* handle as a generic expression; no chance to resolve RECORD */
 248                 Oid                     typid = exprType(expr);
 249
 250                 if (resultTypeId)
 251                         *resultTypeId = typid;
 252                 if (resultTupleDesc)
 253                         *resultTupleDesc = NULL;
 254                 result = get_type_func_class(typid);
 255                 if (result == TYPEFUNC_COMPOSITE && resultTupleDesc)
 256                         *resultTupleDesc = lookup_rowtype_tupdesc_copy(typid, -1);
 257         }
 258
 259         return result;
 260 }
 261
 262 /*
 263  * get_func_result_type
 264  *              As above, but work from a function's OID only
 265  *
 266  * This will not be able to resolve pure-RECORD results nor polymorphism.
 267  */
 268 TypeFuncClass
 269 get_func_result_type(Oid functionId,
 270                                          Oid *resultTypeId,
 271                                          TupleDesc *resultTupleDesc)
 272 {
 273         return internal_get_result_type(functionId,
 274                                                                         NULL,
 275                                                                         NULL,
 276                                                                         resultTypeId,
 277                                                                         resultTupleDesc);
 278 }
 279
 280 /*
 281  * internal_get_result_type -- workhorse code implementing all the above
 282  *
 283  * funcid must always be supplied.      call_expr and rsinfo can be NULL if not
 284  * available.  We will return TYPEFUNC_RECORD, and store NULL into
 285  * *resultTupleDesc, if we cannot deduce the complete result rowtype from
 286  * the available information.
 287  */
 288 static TypeFuncClass
 289 internal_get_result_type(Oid funcid,
 290                                                  Node *call_expr,
 291                                                  ReturnSetInfo *rsinfo,
 292                                                  Oid *resultTypeId,
 293                                                  TupleDesc *resultTupleDesc)
 294 {
 295         TypeFuncClass result;
 296         HeapTuple       tp;
 297         Form_pg_proc procform;
 298         Oid                     rettype;
 299         TupleDesc       tupdesc;
 300
 301         /* First fetch the function's pg_proc row to inspect its rettype */
 302         tp = SearchSysCache(PROCOID,
 303                                                 ObjectIdGetDatum(funcid),
 304                                                 0, 0, 0);
 305         if (!HeapTupleIsValid(tp))
 306                 elog(ERROR, "cache lookup failed for function %u", funcid);
 307         procform = (Form_pg_proc) GETSTRUCT(tp);
 308
 309         rettype = procform->prorettype;
 310
 311         /* Check for OUT parameters defining a RECORD result */
 312         tupdesc = build_function_result_tupdesc_t(tp);
 313         if (tupdesc)
 314         {
 315                 /*
 316                  * It has OUT parameters, so it's basically like a regular composite
 317                  * type, except we have to be able to resolve any polymorphic OUT
 318                  * parameters.
 319                  */
 320                 if (resultTypeId)
 321                         *resultTypeId = rettype;
 322
 323                 if (resolve_polymorphic_tupdesc(tupdesc,
 324                                                                                 &procform->proargtypes,
 325                                                                                 call_expr))
 326                 {
 327                         if (tupdesc->tdtypeid == RECORDOID &&
 328                                 tupdesc->tdtypmod < 0)
 329                                 assign_record_type_typmod(tupdesc);
 330                         if (resultTupleDesc)
 331                                 *resultTupleDesc = tupdesc;
 332                         result = TYPEFUNC_COMPOSITE;
 333                 }
 334                 else
 335                 {
 336                         if (resultTupleDesc)
 337                                 *resultTupleDesc = NULL;
 338                         result = TYPEFUNC_RECORD;
 339                 }
 340
 341                 ReleaseSysCache(tp);
 342
 343                 return result;
 344         }
 345
 346         /*
 347          * If scalar polymorphic result, try to resolve it.
 348          */
 349         if (IsPolymorphicType(rettype))
 350         {
 351                 Oid                     newrettype = exprType(call_expr);
 352
 353                 if (newrettype == InvalidOid)   /* this probably should not happen */
 354                         ereport(ERROR,
 355                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
 356                                          errmsg("could not determine actual result type for function \"%s\" declared to return type %s",
 357                                                         NameStr(procform->proname),
 358                                                         format_type_be(rettype))));
 359                 rettype = newrettype;
 360         }
 361
 362         if (resultTypeId)
 363                 *resultTypeId = rettype;
 364         if (resultTupleDesc)
 365                 *resultTupleDesc = NULL;        /* default result */
 366
 367         /* Classify the result type */
 368         result = get_type_func_class(rettype);
 369         switch (result)
 370         {
 371                 case TYPEFUNC_COMPOSITE:
 372                         if (resultTupleDesc)
 373                                 *resultTupleDesc = lookup_rowtype_tupdesc_copy(rettype, -1);
 374                         /* Named composite types can't have any polymorphic columns */
 375                         break;
 376                 case TYPEFUNC_SCALAR:
 377                         break;
 378                 case TYPEFUNC_RECORD:
 379                         /* We must get the tupledesc from call context */
 380                         if (rsinfo && IsA(rsinfo, ReturnSetInfo) &&
 381                                 rsinfo->expectedDesc != NULL)
 382                         {
 383                                 result = TYPEFUNC_COMPOSITE;
 384                                 if (resultTupleDesc)
 385                                         *resultTupleDesc = rsinfo->expectedDesc;
 386                                 /* Assume no polymorphic columns here, either */
 387                         }
 388                         break;
 389                 default:
 390                         break;
 391         }
 392
 393         ReleaseSysCache(tp);
 394
 395         return result;
 396 }
 397
 398 /*
 399  * Given the result tuple descriptor for a function with OUT parameters,
 400  * replace any polymorphic columns (ANYELEMENT etc) with correct data types
 401  * deduced from the input arguments. Returns TRUE if able to deduce all types,
 402  * FALSE if not.
 403  */
 404 static bool
 405 resolve_polymorphic_tupdesc(TupleDesc tupdesc, oidvector *declared_args,
 406                                                         Node *call_expr)
 407 {
 408         int                     natts = tupdesc->natts;
 409         int                     nargs = declared_args->dim1;
 410         bool            have_anyelement_result = false;
 411         bool            have_anyarray_result = false;
 412         bool            have_anynonarray = false;
 413         bool            have_anyenum = false;
 414         Oid                     anyelement_type = InvalidOid;
 415         Oid                     anyarray_type = InvalidOid;
 416         int                     i;
 417
 418         /* See if there are any polymorphic outputs; quick out if not */
 419         for (i = 0; i < natts; i++)
 420         {
 421                 switch (tupdesc->attrs[i]->atttypid)
 422                 {
 423                         case ANYELEMENTOID:
 424                                 have_anyelement_result = true;
 425                                 break;
 426                         case ANYARRAYOID:
 427                                 have_anyarray_result = true;
 428                                 break;
 429                         case ANYNONARRAYOID:
 430                                 have_anyelement_result = true;
 431                                 have_anynonarray = true;
 432                                 break;
 433                         case ANYENUMOID:
 434                                 have_anyelement_result = true;
 435                                 have_anyenum = true;
 436                                 break;
 437                         default:
 438                                 break;
 439                 }
 440         }
 441         if (!have_anyelement_result && !have_anyarray_result)
 442                 return true;
 443
 444         /*
 445          * Otherwise, extract actual datatype(s) from input arguments.  (We assume
 446          * the parser already validated consistency of the arguments.)
 447          */
 448         if (!call_expr)
 449                 return false;                   /* no hope */
 450
 451         for (i = 0; i < nargs; i++)
 452         {
 453                 switch (declared_args->values[i])
 454                 {
 455                         case ANYELEMENTOID:
 456                         case ANYNONARRAYOID:
 457                         case ANYENUMOID:
 458                                 if (!OidIsValid(anyelement_type))
 459                                         anyelement_type = get_call_expr_argtype(call_expr, i);
 460                                 break;
 461                         case ANYARRAYOID:
 462                                 if (!OidIsValid(anyarray_type))
 463                                         anyarray_type = get_call_expr_argtype(call_expr, i);
 464                                 break;
 465                         default:
 466                                 break;
 467                 }
 468         }
 469
 470         /* If nothing found, parser messed up */
 471         if (!OidIsValid(anyelement_type) && !OidIsValid(anyarray_type))
 472                 return false;
 473
 474         /* If needed, deduce one polymorphic type from the other */
 475         if (have_anyelement_result && !OidIsValid(anyelement_type))
 476                 anyelement_type = resolve_generic_type(ANYELEMENTOID,
 477                                                                                            anyarray_type,
 478                                                                                            ANYARRAYOID);
 479         if (have_anyarray_result && !OidIsValid(anyarray_type))
 480                 anyarray_type = resolve_generic_type(ANYARRAYOID,
 481                                                                                          anyelement_type,
 482                                                                                          ANYELEMENTOID);
 483
 484         /* Enforce ANYNONARRAY if needed */
 485         if (have_anynonarray && type_is_array(anyelement_type))
 486                 return false;
 487
 488         /* Enforce ANYENUM if needed */
 489         if (have_anyenum && !type_is_enum(anyelement_type))
 490                 return false;
 491
 492         /* And finally replace the tuple column types as needed */
 493         for (i = 0; i < natts; i++)
 494         {
 495                 switch (tupdesc->attrs[i]->atttypid)
 496                 {
 497                         case ANYELEMENTOID:
 498                         case ANYNONARRAYOID:
 499                         case ANYENUMOID:
 500                                 TupleDescInitEntry(tupdesc, i + 1,
 501                                                                    NameStr(tupdesc->attrs[i]->attname),
 502                                                                    anyelement_type,
 503                                                                    -1,
 504                                                                    0);
 505                                 break;
 506                         case ANYARRAYOID:
 507                                 TupleDescInitEntry(tupdesc, i + 1,
 508                                                                    NameStr(tupdesc->attrs[i]->attname),
 509                                                                    anyarray_type,
 510                                                                    -1,
 511                                                                    0);
 512                                 break;
 513                         default:
 514                                 break;
 515                 }
 516         }
 517
 518         return true;
 519 }
 520
 521 /*
 522  * Given the declared argument types and modes for a function, replace any
 523  * polymorphic types (ANYELEMENT etc) with correct data types deduced from the
 524  * input arguments.  Returns TRUE if able to deduce all types, FALSE if not.
 525  * This is the same logic as resolve_polymorphic_tupdesc, but with a different
 526  * argument representation.
 527  *
 528  * argmodes may be NULL, in which case all arguments are assumed to be IN mode.
 529  */
 530 bool
 531 resolve_polymorphic_argtypes(int numargs, Oid *argtypes, char *argmodes,
 532                                                          Node *call_expr)
 533 {
 534         bool            have_anyelement_result = false;
 535         bool            have_anyarray_result = false;
 536         Oid                     anyelement_type = InvalidOid;
 537         Oid                     anyarray_type = InvalidOid;
 538         int                     inargno;
 539         int                     i;
 540
 541         /* First pass: resolve polymorphic inputs, check for outputs */
 542         inargno = 0;
 543         for (i = 0; i < numargs; i++)
 544         {
 545                 char            argmode = argmodes ? argmodes[i] : PROARGMODE_IN;
 546
 547                 switch (argtypes[i])
 548                 {
 549                         case ANYELEMENTOID:
 550                         case ANYNONARRAYOID:
 551                         case ANYENUMOID:
 552                                 if (argmode == PROARGMODE_OUT || argmode == PROARGMODE_TABLE)
 553                                         have_anyelement_result = true;
 554                                 else
 555                                 {
 556                                         if (!OidIsValid(anyelement_type))
 557                                         {
 558                                                 anyelement_type = get_call_expr_argtype(call_expr,
 559                                                                                                                                 inargno);
 560                                                 if (!OidIsValid(anyelement_type))
 561                                                         return false;
 562                                         }
 563                                         argtypes[i] = anyelement_type;
 564                                 }
 565                                 break;
 566                         case ANYARRAYOID:
 567                                 if (argmode == PROARGMODE_OUT || argmode == PROARGMODE_TABLE)
 568                                         have_anyarray_result = true;
 569                                 else
 570                                 {
 571                                         if (!OidIsValid(anyarray_type))
 572                                         {
 573                                                 anyarray_type = get_call_expr_argtype(call_expr,
 574                                                                                                                           inargno);
 575                                                 if (!OidIsValid(anyarray_type))
 576                                                         return false;
 577                                         }
 578                                         argtypes[i] = anyarray_type;
 579                                 }
 580                                 break;
 581                         default:
 582                                 break;
 583                 }
 584                 if (argmode != PROARGMODE_OUT && argmode != PROARGMODE_TABLE)
 585                         inargno++;
 586         }
 587
 588         /* Done? */
 589         if (!have_anyelement_result && !have_anyarray_result)
 590                 return true;
 591
 592         /* If no input polymorphics, parser messed up */
 593         if (!OidIsValid(anyelement_type) && !OidIsValid(anyarray_type))
 594                 return false;
 595
 596         /* If needed, deduce one polymorphic type from the other */
 597         if (have_anyelement_result && !OidIsValid(anyelement_type))
 598                 anyelement_type = resolve_generic_type(ANYELEMENTOID,
 599                                                                                            anyarray_type,
 600                                                                                            ANYARRAYOID);
 601         if (have_anyarray_result && !OidIsValid(anyarray_type))
 602                 anyarray_type = resolve_generic_type(ANYARRAYOID,
 603                                                                                          anyelement_type,
 604                                                                                          ANYELEMENTOID);
 605
 606         /* XXX do we need to enforce ANYNONARRAY or ANYENUM here?  I think not */
 607
 608         /* And finally replace the output column types as needed */
 609         for (i = 0; i < numargs; i++)
 610         {
 611                 switch (argtypes[i])
 612                 {
 613                         case ANYELEMENTOID:
 614                         case ANYNONARRAYOID:
 615                         case ANYENUMOID:
 616                                 argtypes[i] = anyelement_type;
 617                                 break;
 618                         case ANYARRAYOID:
 619                                 argtypes[i] = anyarray_type;
 620                                 break;
 621                         default:
 622                                 break;
 623                 }
 624         }
 625
 626         return true;
 627 }
 628
 629 /*
 630  * get_type_func_class
 631  *              Given the type OID, obtain its TYPEFUNC classification.
 632  *
 633  * This is intended to centralize a bunch of formerly ad-hoc code for
 634  * classifying types.  The categories used here are useful for deciding
 635  * how to handle functions returning the datatype.
 636  */
 637 static TypeFuncClass
 638 get_type_func_class(Oid typid)
 639 {
 640         switch (get_typtype(typid))
 641         {
 642                 case TYPTYPE_COMPOSITE:
 643                         return TYPEFUNC_COMPOSITE;
 644                 case TYPTYPE_BASE:
 645                 case TYPTYPE_DOMAIN:
 646                 case TYPTYPE_ENUM:
 647                         return TYPEFUNC_SCALAR;
 648                 case TYPTYPE_PSEUDO:
 649                         if (typid == RECORDOID)
 650                                 return TYPEFUNC_RECORD;
 651
 652                         /*
 653                          * We treat VOID and CSTRING as legitimate scalar datatypes,
 654                          * mostly for the convenience of the JDBC driver (which wants to
 655                          * be able to do "SELECT * FROM foo()" for all legitimately
 656                          * user-callable functions).
 657                          */
 658                         if (typid == VOIDOID || typid == CSTRINGOID)
 659                                 return TYPEFUNC_SCALAR;
 660                         return TYPEFUNC_OTHER;
 661         }
 662         /* shouldn't get here, probably */
 663         return TYPEFUNC_OTHER;
 664 }
 665
 666
 667 /*
 668  * get_func_arg_info
 669  *
 670  * Fetch info about the argument types, names, and IN/OUT modes from the
 671  * pg_proc tuple.  Return value is the total number of arguments.
 672  * Other results are palloc'd.  *p_argtypes is always filled in, but
 673  * *p_argnames and *p_argmodes will be set NULL in the default cases
 674  * (no names, and all IN arguments, respectively).
 675  *
 676  * Note that this function simply fetches what is in the pg_proc tuple;
 677  * it doesn't do any interpretation of polymorphic types.
 678  */
 679 int
 680 get_func_arg_info(HeapTuple procTup,
 681                                   Oid **p_argtypes, char ***p_argnames, char **p_argmodes)
 682 {
 683         Form_pg_proc procStruct = (Form_pg_proc) GETSTRUCT(procTup);
 684         Datum           proallargtypes;
 685         Datum           proargmodes;
 686         Datum           proargnames;
 687         bool            isNull;
 688         ArrayType  *arr;
 689         int                     numargs;
 690         Datum      *elems;
 691         int                     nelems;
 692         int                     i;
 693
 694         /* First discover the total number of parameters and get their types */
 695         proallargtypes = SysCacheGetAttr(PROCOID, procTup,
 696                                                                          Anum_pg_proc_proallargtypes,
 697                                                                          &isNull);
 698         if (!isNull)
 699         {
 700                 /*
 701                  * We expect the arrays to be 1-D arrays of the right types; verify
 702                  * that.  For the OID and char arrays, we don't need to use
 703                  * deconstruct_array() since the array data is just going to look like
 704                  * a C array of values.
 705                  */
 706                 arr = DatumGetArrayTypeP(proallargtypes);               /* ensure not toasted */
 707                 numargs = ARR_DIMS(arr)[0];
 708                 if (ARR_NDIM(arr) != 1 ||
 709                         numargs < 0 ||
 710                         ARR_HASNULL(arr) ||
 711                         ARR_ELEMTYPE(arr) != OIDOID)
 712                         elog(ERROR, "proallargtypes is not a 1-D Oid array");
 713                 Assert(numargs >= procStruct->pronargs);
 714                 *p_argtypes = (Oid *) palloc(numargs * sizeof(Oid));
 715                 memcpy(*p_argtypes, ARR_DATA_PTR(arr),
 716                            numargs * sizeof(Oid));
 717         }
 718         else
 719         {
 720                 /* If no proallargtypes, use proargtypes */
 721                 numargs = procStruct->proargtypes.dim1;
 722                 Assert(numargs == procStruct->pronargs);
 723                 *p_argtypes = (Oid *) palloc(numargs * sizeof(Oid));
 724                 memcpy(*p_argtypes, procStruct->proargtypes.values,
 725                            numargs * sizeof(Oid));
 726         }
 727
 728         /* Get argument names, if available */
 729         proargnames = SysCacheGetAttr(PROCOID, procTup,
 730                                                                   Anum_pg_proc_proargnames,
 731                                                                   &isNull);
 732         if (isNull)
 733                 *p_argnames = NULL;
 734         else
 735         {
 736                 deconstruct_array(DatumGetArrayTypeP(proargnames),
 737                                                   TEXTOID, -1, false, 'i',
 738                                                   &elems, NULL, &nelems);
 739                 if (nelems != numargs)  /* should not happen */
 740                         elog(ERROR, "proargnames must have the same number of elements as the function has arguments");
 741                 *p_argnames = (char **) palloc(sizeof(char *) * numargs);
 742                 for (i = 0; i < numargs; i++)
 743                         (*p_argnames)[i] = TextDatumGetCString(elems[i]);
 744         }
 745
 746         /* Get argument modes, if available */
 747         proargmodes = SysCacheGetAttr(PROCOID, procTup,
 748                                                                   Anum_pg_proc_proargmodes,
 749                                                                   &isNull);
 750         if (isNull)
 751                 *p_argmodes = NULL;
 752         else
 753         {
 754                 arr = DatumGetArrayTypeP(proargmodes);  /* ensure not toasted */
 755                 if (ARR_NDIM(arr) != 1 ||
 756                         ARR_DIMS(arr)[0] != numargs ||
 757                         ARR_HASNULL(arr) ||
 758                         ARR_ELEMTYPE(arr) != CHAROID)
 759                         elog(ERROR, "proargmodes is not a 1-D char array");
 760                 *p_argmodes = (char *) palloc(numargs * sizeof(char));
 761                 memcpy(*p_argmodes, ARR_DATA_PTR(arr),
 762                            numargs * sizeof(char));
 763         }
 764
 765         return numargs;
 766 }
 767
 768
 769 /*
 770  * get_func_result_name
 771  *
 772  * If the function has exactly one output parameter, and that parameter
 773  * is named, return the name (as a palloc'd string).  Else return NULL.
 774  *
 775  * This is used to determine the default output column name for functions
 776  * returning scalar types.
 777  */
 778 char *
 779 get_func_result_name(Oid functionId)
 780 {
 781         char       *result;
 782         HeapTuple       procTuple;
 783         Datum           proargmodes;
 784         Datum           proargnames;
 785         bool            isnull;
 786         ArrayType  *arr;
 787         int                     numargs;
 788         char       *argmodes;
 789         Datum      *argnames;
 790         int                     numoutargs;
 791         int                     nargnames;
 792         int                     i;
 793
 794         /* First fetch the function's pg_proc row */
 795         procTuple = SearchSysCache(PROCOID,
 796                                                            ObjectIdGetDatum(functionId),
 797                                                            0, 0, 0);
 798         if (!HeapTupleIsValid(procTuple))
 799                 elog(ERROR, "cache lookup failed for function %u", functionId);
 800
 801         /* If there are no named OUT parameters, return NULL */
 802         if (heap_attisnull(procTuple, Anum_pg_proc_proargmodes) ||
 803                 heap_attisnull(procTuple, Anum_pg_proc_proargnames))
 804                 result = NULL;
 805         else
 806         {
 807                 /* Get the data out of the tuple */
 808                 proargmodes = SysCacheGetAttr(PROCOID, procTuple,
 809                                                                           Anum_pg_proc_proargmodes,
 810                                                                           &isnull);
 811                 Assert(!isnull);
 812                 proargnames = SysCacheGetAttr(PROCOID, procTuple,
 813                                                                           Anum_pg_proc_proargnames,
 814                                                                           &isnull);
 815                 Assert(!isnull);
 816
 817                 /*
 818                  * We expect the arrays to be 1-D arrays of the right types; verify
 819                  * that.  For the char array, we don't need to use deconstruct_array()
 820                  * since the array data is just going to look like a C array of
 821                  * values.
 822                  */
 823                 arr = DatumGetArrayTypeP(proargmodes);  /* ensure not toasted */
 824                 numargs = ARR_DIMS(arr)[0];
 825                 if (ARR_NDIM(arr) != 1 ||
 826                         numargs < 0 ||
 827                         ARR_HASNULL(arr) ||
 828                         ARR_ELEMTYPE(arr) != CHAROID)
 829                         elog(ERROR, "proargmodes is not a 1-D char array");
 830                 argmodes = (char *) ARR_DATA_PTR(arr);
 831                 arr = DatumGetArrayTypeP(proargnames);  /* ensure not toasted */
 832                 if (ARR_NDIM(arr) != 1 ||
 833                         ARR_DIMS(arr)[0] != numargs ||
 834                         ARR_HASNULL(arr) ||
 835                         ARR_ELEMTYPE(arr) != TEXTOID)
 836                         elog(ERROR, "proargnames is not a 1-D text array");
 837                 deconstruct_array(arr, TEXTOID, -1, false, 'i',
 838                                                   &argnames, NULL, &nargnames);
 839                 Assert(nargnames == numargs);
 840
 841                 /* scan for output argument(s) */
 842                 result = NULL;
 843                 numoutargs = 0;
 844                 for (i = 0; i < numargs; i++)
 845                 {
 846                         if (argmodes[i] == PROARGMODE_IN ||
 847                                 argmodes[i] == PROARGMODE_VARIADIC)
 848                                 continue;
 849                         Assert(argmodes[i] == PROARGMODE_OUT ||
 850                                    argmodes[i] == PROARGMODE_INOUT ||
 851                                    argmodes[i] == PROARGMODE_TABLE);
 852                         if (++numoutargs > 1)
 853                         {
 854                                 /* multiple out args, so forget it */
 855                                 result = NULL;
 856                                 break;
 857                         }
 858                         result = TextDatumGetCString(argnames[i]);
 859                         if (result == NULL || result[0] == '\0')
 860                         {
 861                                 /* Parameter is not named, so forget it */
 862                                 result = NULL;
 863                                 break;
 864                         }
 865                 }
 866         }
 867
 868         ReleaseSysCache(procTuple);
 869
 870         return result;
 871 }
 872
 873
 874 /*
 875  * build_function_result_tupdesc_t
 876  *
 877  * Given a pg_proc row for a function, return a tuple descriptor for the
 878  * result rowtype, or NULL if the function does not have OUT parameters.
 879  *
 880  * Note that this does not handle resolution of polymorphic types;
 881  * that is deliberate.
 882  */
 883 TupleDesc
 884 build_function_result_tupdesc_t(HeapTuple procTuple)
 885 {
 886         Form_pg_proc procform = (Form_pg_proc) GETSTRUCT(procTuple);
 887         Datum           proallargtypes;
 888         Datum           proargmodes;
 889         Datum           proargnames;
 890         bool            isnull;
 891
 892         /* Return NULL if the function isn't declared to return RECORD */
 893         if (procform->prorettype != RECORDOID)
 894                 return NULL;
 895
 896         /* If there are no OUT parameters, return NULL */
 897         if (heap_attisnull(procTuple, Anum_pg_proc_proallargtypes) ||
 898                 heap_attisnull(procTuple, Anum_pg_proc_proargmodes))
 899                 return NULL;
 900
 901         /* Get the data out of the tuple */
 902         proallargtypes = SysCacheGetAttr(PROCOID, procTuple,
 903                                                                          Anum_pg_proc_proallargtypes,
 904                                                                          &isnull);
 905         Assert(!isnull);
 906         proargmodes = SysCacheGetAttr(PROCOID, procTuple,
 907                                                                   Anum_pg_proc_proargmodes,
 908                                                                   &isnull);
 909         Assert(!isnull);
 910         proargnames = SysCacheGetAttr(PROCOID, procTuple,
 911                                                                   Anum_pg_proc_proargnames,
 912                                                                   &isnull);
 913         if (isnull)
 914                 proargnames = PointerGetDatum(NULL);    /* just to be sure */
 915
 916         return build_function_result_tupdesc_d(proallargtypes,
 917                                                                                    proargmodes,
 918                                                                                    proargnames);
 919 }
 920
 921 /*
 922  * build_function_result_tupdesc_d
 923  *
 924  * Build a RECORD function's tupledesc from the pg_proc proallargtypes,
 925  * proargmodes, and proargnames arrays.  This is split out for the
 926  * convenience of ProcedureCreate, which needs to be able to compute the
 927  * tupledesc before actually creating the function.
 928  *
 929  * Returns NULL if there are not at least two OUT or INOUT arguments.
 930  */
 931 TupleDesc
 932 build_function_result_tupdesc_d(Datum proallargtypes,
 933                                                                 Datum proargmodes,
 934                                                                 Datum proargnames)
 935 {
 936         TupleDesc       desc;
 937         ArrayType  *arr;
 938         int                     numargs;
 939         Oid                *argtypes;
 940         char       *argmodes;
 941         Datum      *argnames = NULL;
 942         Oid                *outargtypes;
 943         char      **outargnames;
 944         int                     numoutargs;
 945         int                     nargnames;
 946         int                     i;
 947
 948         /* Can't have output args if columns are null */
 949         if (proallargtypes == PointerGetDatum(NULL) ||
 950                 proargmodes == PointerGetDatum(NULL))
 951                 return NULL;
 952
 953         /*
 954          * We expect the arrays to be 1-D arrays of the right types; verify that.
 955          * For the OID and char arrays, we don't need to use deconstruct_array()
 956          * since the array data is just going to look like a C array of values.
 957          */
 958         arr = DatumGetArrayTypeP(proallargtypes);       /* ensure not toasted */
 959         numargs = ARR_DIMS(arr)[0];
 960         if (ARR_NDIM(arr) != 1 ||
 961                 numargs < 0 ||
 962                 ARR_HASNULL(arr) ||
 963                 ARR_ELEMTYPE(arr) != OIDOID)
 964                 elog(ERROR, "proallargtypes is not a 1-D Oid array");
 965         argtypes = (Oid *) ARR_DATA_PTR(arr);
 966         arr = DatumGetArrayTypeP(proargmodes);          /* ensure not toasted */
 967         if (ARR_NDIM(arr) != 1 ||
 968                 ARR_DIMS(arr)[0] != numargs ||
 969                 ARR_HASNULL(arr) ||
 970                 ARR_ELEMTYPE(arr) != CHAROID)
 971                 elog(ERROR, "proargmodes is not a 1-D char array");
 972         argmodes = (char *) ARR_DATA_PTR(arr);
 973         if (proargnames != PointerGetDatum(NULL))
 974         {
 975                 arr = DatumGetArrayTypeP(proargnames);  /* ensure not toasted */
 976                 if (ARR_NDIM(arr) != 1 ||
 977                         ARR_DIMS(arr)[0] != numargs ||
 978                         ARR_HASNULL(arr) ||
 979                         ARR_ELEMTYPE(arr) != TEXTOID)
 980                         elog(ERROR, "proargnames is not a 1-D text array");
 981                 deconstruct_array(arr, TEXTOID, -1, false, 'i',
 982                                                   &argnames, NULL, &nargnames);
 983                 Assert(nargnames == numargs);
 984         }
 985
 986         /* zero elements probably shouldn't happen, but handle it gracefully */
 987         if (numargs <= 0)
 988                 return NULL;
 989
 990         /* extract output-argument types and names */
 991         outargtypes = (Oid *) palloc(numargs * sizeof(Oid));
 992         outargnames = (char **) palloc(numargs * sizeof(char *));
 993         numoutargs = 0;
 994         for (i = 0; i < numargs; i++)
 995         {
 996                 char       *pname;
 997
 998                 if (argmodes[i] == PROARGMODE_IN ||
 999                         argmodes[i] == PROARGMODE_VARIADIC)
1000                         continue;
1001                 Assert(argmodes[i] == PROARGMODE_OUT ||
1002                            argmodes[i] == PROARGMODE_INOUT ||
1003                            argmodes[i] == PROARGMODE_TABLE);
1004                 outargtypes[numoutargs] = argtypes[i];
1005                 if (argnames)
1006                         pname = TextDatumGetCString(argnames[i]);
1007                 else
1008                         pname = NULL;
1009                 if (pname == NULL || pname[0] == '\0')
1010                 {
1011                         /* Parameter is not named, so gin up a column name */
1012                         pname = (char *) palloc(32);
1013                         snprintf(pname, 32, "column%d", numoutargs + 1);
1014                 }
1015                 outargnames[numoutargs] = pname;
1016                 numoutargs++;
1017         }
1018
1019         /*
1020          * If there is no output argument, or only one, the function does not
1021          * return tuples.
1022          */
1023         if (numoutargs < 2)
1024                 return NULL;
1025
1026         desc = CreateTemplateTupleDesc(numoutargs, false);
1027         for (i = 0; i < numoutargs; i++)
1028         {
1029                 TupleDescInitEntry(desc, i + 1,
1030                                                    outargnames[i],
1031                                                    outargtypes[i],
1032                                                    -1,
1033                                                    0);
1034         }
1035
1036         return desc;
1037 }
1038
1039
1040 /*
1041  * RelationNameGetTupleDesc
1042  *
1043  * Given a (possibly qualified) relation name, build a TupleDesc.
1044  *
1045  * Note: while this works as advertised, it's seldom the best way to
1046  * build a tupdesc for a function's result type.  It's kept around
1047  * only for backwards compatibility with existing user-written code.
1048  */
1049 TupleDesc
1050 RelationNameGetTupleDesc(const char *relname)
1051 {
1052         RangeVar   *relvar;
1053         Relation        rel;
1054         TupleDesc       tupdesc;
1055         List       *relname_list;
1056
1057         /* Open relation and copy the tuple description */
1058         relname_list = stringToQualifiedNameList(relname);
1059         relvar = makeRangeVarFromNameList(relname_list);
1060         rel = relation_openrv(relvar, AccessShareLock);
1061         tupdesc = CreateTupleDescCopy(RelationGetDescr(rel));
1062         relation_close(rel, AccessShareLock);
1063
1064         return tupdesc;
1065 }
1066
1067 /*
1068  * TypeGetTupleDesc
1069  *
1070  * Given a type Oid, build a TupleDesc.  (In most cases you should be
1071  * using get_call_result_type or one of its siblings instead of this
1072  * routine, so that you can handle OUT parameters, RECORD result type,
1073  * and polymorphic results.)
1074  *
1075  * If the type is composite, *and* a colaliases List is provided, *and*
1076  * the List is of natts length, use the aliases instead of the relation
1077  * attnames.  (NB: this usage is deprecated since it may result in
1078  * creation of unnecessary transient record types.)
1079  *
1080  * If the type is a base type, a single item alias List is required.
1081  */
1082 TupleDesc
1083 TypeGetTupleDesc(Oid typeoid, List *colaliases)
1084 {
1085         TypeFuncClass functypclass = get_type_func_class(typeoid);
1086         TupleDesc       tupdesc = NULL;
1087
1088         /*
1089          * Build a suitable tupledesc representing the output rows
1090          */
1091         if (functypclass == TYPEFUNC_COMPOSITE)
1092         {
1093                 /* Composite data type, e.g. a table's row type */
1094                 tupdesc = lookup_rowtype_tupdesc_copy(typeoid, -1);
1095
1096                 if (colaliases != NIL)
1097                 {
1098                         int                     natts = tupdesc->natts;
1099                         int                     varattno;
1100
1101                         /* does the list length match the number of attributes? */
1102                         if (list_length(colaliases) != natts)
1103                                 ereport(ERROR,
1104                                                 (errcode(ERRCODE_DATATYPE_MISMATCH),
1105                                                  errmsg("number of aliases does not match number of columns")));
1106
1107                         /* OK, use the aliases instead */
1108                         for (varattno = 0; varattno < natts; varattno++)
1109                         {
1110                                 char       *label = strVal(list_nth(colaliases, varattno));
1111
1112                                 if (label != NULL)
1113                                         namestrcpy(&(tupdesc->attrs[varattno]->attname), label);
1114                         }
1115
1116                         /* The tuple type is now an anonymous record type */
1117                         tupdesc->tdtypeid = RECORDOID;
1118                         tupdesc->tdtypmod = -1;
1119                 }
1120         }
1121         else if (functypclass == TYPEFUNC_SCALAR)
1122         {
1123                 /* Base data type, i.e. scalar */
1124                 char       *attname;
1125
1126                 /* the alias list is required for base types */
1127                 if (colaliases == NIL)
1128                         ereport(ERROR,
1129                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
1130                                          errmsg("no column alias was provided")));
1131
1132                 /* the alias list length must be 1 */
1133                 if (list_length(colaliases) != 1)
1134                         ereport(ERROR,
1135                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
1136                           errmsg("number of aliases does not match number of columns")));
1137
1138                 /* OK, get the column alias */
1139                 attname = strVal(linitial(colaliases));
1140
1141                 tupdesc = CreateTemplateTupleDesc(1, false);
1142                 TupleDescInitEntry(tupdesc,
1143                                                    (AttrNumber) 1,
1144                                                    attname,
1145                                                    typeoid,
1146                                                    -1,
1147                                                    0);
1148         }
1149         else if (functypclass == TYPEFUNC_RECORD)
1150         {
1151                 /* XXX can't support this because typmod wasn't passed in ... */
1152                 ereport(ERROR,
1153                                 (errcode(ERRCODE_DATATYPE_MISMATCH),
1154                                  errmsg("could not determine row description for function returning record")));
1155         }
1156         else
1157         {
1158                 /* crummy error message, but parser should have caught this */
1159                 elog(ERROR, "function in FROM has unsupported return type");
1160         }
1161
1162         return tupdesc;
1163 }