src/backend/catalog/pg_proc.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * pg_proc.c
   4  *        routines to support manipulation of the pg_proc relation
   5  *
   6  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  *
  10  * IDENTIFICATION
  11  *        $PostgreSQL: pgsql/src/backend/catalog/pg_proc.c,v 1.125 2005/03/29 19:44:23 tgl Exp $
  12  *
  13  *-------------------------------------------------------------------------
  14  */
  15 #include "postgres.h"
  16
  17 #include "access/heapam.h"
  18 #include "catalog/catname.h"
  19 #include "catalog/dependency.h"
  20 #include "catalog/indexing.h"
  21 #include "catalog/pg_proc.h"
  22 #include "catalog/pg_type.h"
  23 #include "executor/functions.h"
  24 #include "miscadmin.h"
  25 #include "mb/pg_wchar.h"
  26 #include "parser/parse_type.h"
  27 #include "tcop/pquery.h"
  28 #include "tcop/tcopprot.h"
  29 #include "utils/acl.h"
  30 #include "utils/builtins.h"
  31 #include "utils/lsyscache.h"
  32 #include "utils/syscache.h"
  33
  34
  35 /* GUC parameter */
  36 bool            check_function_bodies = true;
  37
  38
  39 Datum           fmgr_internal_validator(PG_FUNCTION_ARGS);
  40 Datum           fmgr_c_validator(PG_FUNCTION_ARGS);
  41 Datum           fmgr_sql_validator(PG_FUNCTION_ARGS);
  42
  43 static Datum create_parameternames_array(int parameterCount,
  44                                                         const char *parameterNames[]);
  45 static void sql_function_parse_error_callback(void *arg);
  46 static int match_prosrc_to_query(const char *prosrc, const char *queryText,
  47                                           int cursorpos);
  48 static bool match_prosrc_to_literal(const char *prosrc, const char *literal,
  49                                                 int cursorpos, int *newcursorpos);
  50
  51
  52 /* ----------------------------------------------------------------
  53  *              ProcedureCreate
  54  * ----------------------------------------------------------------
  55  */
  56 Oid
  57 ProcedureCreate(const char *procedureName,
  58                                 Oid procNamespace,
  59                                 bool replace,
  60                                 bool returnsSet,
  61                                 Oid returnType,
  62                                 Oid languageObjectId,
  63                                 Oid languageValidator,
  64                                 const char *prosrc,
  65                                 const char *probin,
  66                                 bool isAgg,
  67                                 bool security_definer,
  68                                 bool isStrict,
  69                                 char volatility,
  70                                 int parameterCount,
  71                                 const Oid *parameterTypes,
  72                                 const char *parameterNames[])
  73 {
  74         int                     i;
  75         Relation        rel;
  76         HeapTuple       tup;
  77         HeapTuple       oldtup;
  78         char            nulls[Natts_pg_proc];
  79         Datum           values[Natts_pg_proc];
  80         char            replaces[Natts_pg_proc];
  81         oidvector  *proargtypes;
  82         Datum           namesarray;
  83         Oid                     relid;
  84         NameData        procname;
  85         TupleDesc       tupDesc;
  86         Oid                     retval;
  87         bool            is_update;
  88         ObjectAddress myself,
  89                                 referenced;
  90
  91         /*
  92          * sanity checks
  93          */
  94         Assert(PointerIsValid(prosrc));
  95         Assert(PointerIsValid(probin));
  96
  97         if (parameterCount < 0 || parameterCount > FUNC_MAX_ARGS)
  98                 ereport(ERROR,
  99                                 (errcode(ERRCODE_TOO_MANY_ARGUMENTS),
 100                                  errmsg("functions cannot have more than %d arguments",
 101                                                 FUNC_MAX_ARGS)));
 102
 103         /*
 104          * Do not allow return type ANYARRAY or ANYELEMENT unless at least one
 105          * argument is also ANYARRAY or ANYELEMENT
 106          */
 107         if (returnType == ANYARRAYOID || returnType == ANYELEMENTOID)
 108         {
 109                 bool            genericParam = false;
 110
 111                 for (i = 0; i < parameterCount; i++)
 112                 {
 113                         if (parameterTypes[i] == ANYARRAYOID ||
 114                                 parameterTypes[i] == ANYELEMENTOID)
 115                         {
 116                                 genericParam = true;
 117                                 break;
 118                         }
 119                 }
 120
 121                 if (!genericParam)
 122                         ereport(ERROR,
 123                                         (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
 124                                          errmsg("cannot determine result data type"),
 125                                          errdetail("A function returning \"anyarray\" or \"anyelement\" must have at least one argument of either type.")));
 126         }
 127
 128         /* Convert param types to oidvector */
 129         /* (Probably we should make caller pass it this way to start with) */
 130         proargtypes = buildoidvector(parameterTypes, parameterCount);
 131
 132         /* Process param names, if given */
 133         namesarray = create_parameternames_array(parameterCount, parameterNames);
 134
 135         /*
 136          * don't allow functions of complex types that have the same name as
 137          * existing attributes of the type
 138          */
 139         if (parameterCount == 1 && OidIsValid(parameterTypes[0]) &&
 140                 (relid = typeidTypeRelid(parameterTypes[0])) != InvalidOid &&
 141                 get_attnum(relid, procedureName) != InvalidAttrNumber)
 142                 ereport(ERROR,
 143                                 (errcode(ERRCODE_DUPLICATE_COLUMN),
 144                                  errmsg("\"%s\" is already an attribute of type %s",
 145                                                 procedureName, format_type_be(parameterTypes[0]))));
 146
 147         /*
 148          * All seems OK; prepare the data to be inserted into pg_proc.
 149          */
 150
 151         for (i = 0; i < Natts_pg_proc; ++i)
 152         {
 153                 nulls[i] = ' ';
 154                 values[i] = (Datum) 0;
 155                 replaces[i] = 'r';
 156         }
 157
 158         namestrcpy(&procname, procedureName);
 159         values[Anum_pg_proc_proname - 1] = NameGetDatum(&procname);
 160         values[Anum_pg_proc_pronamespace - 1] = ObjectIdGetDatum(procNamespace);
 161         values[Anum_pg_proc_proowner - 1] = Int32GetDatum(GetUserId());
 162         values[Anum_pg_proc_prolang - 1] = ObjectIdGetDatum(languageObjectId);
 163         values[Anum_pg_proc_proisagg - 1] = BoolGetDatum(isAgg);
 164         values[Anum_pg_proc_prosecdef - 1] = BoolGetDatum(security_definer);
 165         values[Anum_pg_proc_proisstrict - 1] = BoolGetDatum(isStrict);
 166         values[Anum_pg_proc_proretset - 1] = BoolGetDatum(returnsSet);
 167         values[Anum_pg_proc_provolatile - 1] = CharGetDatum(volatility);
 168         values[Anum_pg_proc_pronargs - 1] = UInt16GetDatum(parameterCount);
 169         values[Anum_pg_proc_prorettype - 1] = ObjectIdGetDatum(returnType);
 170         values[Anum_pg_proc_proargtypes - 1] = PointerGetDatum(proargtypes);
 171         /* XXX for now, just null out the new columns */
 172         nulls[Anum_pg_proc_proallargtypes - 1] = 'n';
 173         nulls[Anum_pg_proc_proargmodes - 1] = 'n';
 174         if (namesarray != PointerGetDatum(NULL))
 175                 values[Anum_pg_proc_proargnames - 1] = namesarray;
 176         else
 177                 nulls[Anum_pg_proc_proargnames - 1] = 'n';
 178         values[Anum_pg_proc_prosrc - 1] = DirectFunctionCall1(textin,
 179                                                                           CStringGetDatum(prosrc));
 180         values[Anum_pg_proc_probin - 1] = DirectFunctionCall1(textin,
 181                                                                           CStringGetDatum(probin));
 182         /* start out with empty permissions */
 183         nulls[Anum_pg_proc_proacl - 1] = 'n';
 184
 185         rel = heap_openr(ProcedureRelationName, RowExclusiveLock);
 186         tupDesc = RelationGetDescr(rel);
 187
 188         /* Check for pre-existing definition */
 189         oldtup = SearchSysCache(PROCNAMEARGSNSP,
 190                                                         PointerGetDatum(procedureName),
 191                                                         PointerGetDatum(proargtypes),
 192                                                         ObjectIdGetDatum(procNamespace),
 193                                                         0);
 194
 195         if (HeapTupleIsValid(oldtup))
 196         {
 197                 /* There is one; okay to replace it? */
 198                 Form_pg_proc oldproc = (Form_pg_proc) GETSTRUCT(oldtup);
 199
 200                 if (!replace)
 201                         ereport(ERROR,
 202                                         (errcode(ERRCODE_DUPLICATE_FUNCTION),
 203                                          errmsg("function \"%s\" already exists with same argument types",
 204                                                         procedureName)));
 205                 if (GetUserId() != oldproc->proowner && !superuser())
 206                         aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_PROC,
 207                                                    procedureName);
 208
 209                 /*
 210                  * Not okay to change the return type of the existing proc, since
 211                  * existing rules, views, etc may depend on the return type.
 212                  */
 213                 if (returnType != oldproc->prorettype ||
 214                         returnsSet != oldproc->proretset)
 215                         ereport(ERROR,
 216                                         (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
 217                                 errmsg("cannot change return type of existing function"),
 218                                          errhint("Use DROP FUNCTION first.")));
 219
 220                 /* Can't change aggregate status, either */
 221                 if (oldproc->proisagg != isAgg)
 222                 {
 223                         if (oldproc->proisagg)
 224                                 ereport(ERROR,
 225                                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 226                                                  errmsg("function \"%s\" is an aggregate",
 227                                                                 procedureName)));
 228                         else
 229                                 ereport(ERROR,
 230                                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 231                                                  errmsg("function \"%s\" is not an aggregate",
 232                                                                 procedureName)));
 233                 }
 234
 235                 /* do not change existing ownership or permissions, either */
 236                 replaces[Anum_pg_proc_proowner - 1] = ' ';
 237                 replaces[Anum_pg_proc_proacl - 1] = ' ';
 238
 239                 /* Okay, do it... */
 240                 tup = heap_modifytuple(oldtup, tupDesc, values, nulls, replaces);
 241                 simple_heap_update(rel, &tup->t_self, tup);
 242
 243                 ReleaseSysCache(oldtup);
 244                 is_update = true;
 245         }
 246         else
 247         {
 248                 /* Creating a new procedure */
 249                 tup = heap_formtuple(tupDesc, values, nulls);
 250                 simple_heap_insert(rel, tup);
 251                 is_update = false;
 252         }
 253
 254         /* Need to update indexes for either the insert or update case */
 255         CatalogUpdateIndexes(rel, tup);
 256
 257         retval = HeapTupleGetOid(tup);
 258
 259         /*
 260          * Create dependencies for the new function.  If we are updating an
 261          * existing function, first delete any existing pg_depend entries.
 262          */
 263         if (is_update)
 264                 deleteDependencyRecordsFor(RelOid_pg_proc, retval);
 265
 266         myself.classId = RelOid_pg_proc;
 267         myself.objectId = retval;
 268         myself.objectSubId = 0;
 269
 270         /* dependency on namespace */
 271         referenced.classId = get_system_catalog_relid(NamespaceRelationName);
 272         referenced.objectId = procNamespace;
 273         referenced.objectSubId = 0;
 274         recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
 275
 276         /* dependency on implementation language */
 277         referenced.classId = get_system_catalog_relid(LanguageRelationName);
 278         referenced.objectId = languageObjectId;
 279         referenced.objectSubId = 0;
 280         recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
 281
 282         /* dependency on return type */
 283         referenced.classId = RelOid_pg_type;
 284         referenced.objectId = returnType;
 285         referenced.objectSubId = 0;
 286         recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
 287
 288         /* dependency on input types */
 289         for (i = 0; i < parameterCount; i++)
 290         {
 291                 referenced.classId = RelOid_pg_type;
 292                 referenced.objectId = parameterTypes[i];
 293                 referenced.objectSubId = 0;
 294                 recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
 295         }
 296
 297         heap_freetuple(tup);
 298
 299         heap_close(rel, RowExclusiveLock);
 300
 301         /* Verify function body */
 302         if (OidIsValid(languageValidator))
 303         {
 304                 /* Advance command counter so new tuple can be seen by validator */
 305                 CommandCounterIncrement();
 306                 OidFunctionCall1(languageValidator, ObjectIdGetDatum(retval));
 307         }
 308
 309         return retval;
 310 }
 311
 312
 313 /*
 314  * create_parameternames_array - build proargnames value from an array
 315  * of C strings.  Returns a NULL pointer if no names provided.
 316  */
 317 static Datum
 318 create_parameternames_array(int parameterCount, const char *parameterNames[])
 319 {
 320         Datum           elems[FUNC_MAX_ARGS];
 321         bool            found = false;
 322         ArrayType  *names;
 323         int                     i;
 324
 325         if (!parameterNames)
 326                 return PointerGetDatum(NULL);
 327
 328         for (i = 0; i < parameterCount; i++)
 329         {
 330                 const char *s = parameterNames[i];
 331
 332                 if (s && *s)
 333                         found = true;
 334                 else
 335                         s = "";
 336
 337                 elems[i] = DirectFunctionCall1(textin, CStringGetDatum(s));
 338         }
 339
 340         if (!found)
 341                 return PointerGetDatum(NULL);
 342
 343         names = construct_array(elems, parameterCount, TEXTOID, -1, false, 'i');
 344
 345         return PointerGetDatum(names);
 346 }
 347
 348
 349
 350 /*
 351  * Validator for internal functions
 352  *
 353  * Check that the given internal function name (the "prosrc" value) is
 354  * a known builtin function.
 355  */
 356 Datum
 357 fmgr_internal_validator(PG_FUNCTION_ARGS)
 358 {
 359         Oid                     funcoid = PG_GETARG_OID(0);
 360         HeapTuple       tuple;
 361         Form_pg_proc proc;
 362         bool            isnull;
 363         Datum           tmp;
 364         char       *prosrc;
 365
 366         /*
 367          * We do not honor check_function_bodies since it's unlikely the
 368          * function name will be found later if it isn't there now.
 369          */
 370
 371         tuple = SearchSysCache(PROCOID,
 372                                                    ObjectIdGetDatum(funcoid),
 373                                                    0, 0, 0);
 374         if (!HeapTupleIsValid(tuple))
 375                 elog(ERROR, "cache lookup failed for function %u", funcoid);
 376         proc = (Form_pg_proc) GETSTRUCT(tuple);
 377
 378         tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_prosrc, &isnull);
 379         if (isnull)
 380                 elog(ERROR, "null prosrc");
 381         prosrc = DatumGetCString(DirectFunctionCall1(textout, tmp));
 382
 383         if (fmgr_internal_function(prosrc) == InvalidOid)
 384                 ereport(ERROR,
 385                                 (errcode(ERRCODE_UNDEFINED_FUNCTION),
 386                                  errmsg("there is no built-in function named \"%s\"",
 387                                                 prosrc)));
 388
 389         ReleaseSysCache(tuple);
 390
 391         PG_RETURN_VOID();
 392 }
 393
 394
 395
 396 /*
 397  * Validator for C language functions
 398  *
 399  * Make sure that the library file exists, is loadable, and contains
 400  * the specified link symbol. Also check for a valid function
 401  * information record.
 402  */
 403 Datum
 404 fmgr_c_validator(PG_FUNCTION_ARGS)
 405 {
 406         Oid                     funcoid = PG_GETARG_OID(0);
 407         void       *libraryhandle;
 408         HeapTuple       tuple;
 409         Form_pg_proc proc;
 410         bool            isnull;
 411         Datum           tmp;
 412         char       *prosrc;
 413         char       *probin;
 414
 415         /*
 416          * It'd be most consistent to skip the check if
 417          * !check_function_bodies, but the purpose of that switch is to be
 418          * helpful for pg_dump loading, and for pg_dump loading it's much
 419          * better if we *do* check.
 420          */
 421
 422         tuple = SearchSysCache(PROCOID,
 423                                                    ObjectIdGetDatum(funcoid),
 424                                                    0, 0, 0);
 425         if (!HeapTupleIsValid(tuple))
 426                 elog(ERROR, "cache lookup failed for function %u", funcoid);
 427         proc = (Form_pg_proc) GETSTRUCT(tuple);
 428
 429         tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_prosrc, &isnull);
 430         if (isnull)
 431                 elog(ERROR, "null prosrc");
 432         prosrc = DatumGetCString(DirectFunctionCall1(textout, tmp));
 433
 434         tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_probin, &isnull);
 435         if (isnull)
 436                 elog(ERROR, "null probin");
 437         probin = DatumGetCString(DirectFunctionCall1(textout, tmp));
 438
 439         (void) load_external_function(probin, prosrc, true, &libraryhandle);
 440         (void) fetch_finfo_record(libraryhandle, prosrc);
 441
 442         ReleaseSysCache(tuple);
 443
 444         PG_RETURN_VOID();
 445 }
 446
 447
 448 /*
 449  * Validator for SQL language functions
 450  *
 451  * Parse it here in order to be sure that it contains no syntax errors.
 452  */
 453 Datum
 454 fmgr_sql_validator(PG_FUNCTION_ARGS)
 455 {
 456         Oid                     funcoid = PG_GETARG_OID(0);
 457         HeapTuple       tuple;
 458         Form_pg_proc proc;
 459         List       *querytree_list;
 460         bool            isnull;
 461         Datum           tmp;
 462         char       *prosrc;
 463         ErrorContextCallback sqlerrcontext;
 464         char            functyptype;
 465         bool            haspolyarg;
 466         int                     i;
 467
 468         tuple = SearchSysCache(PROCOID,
 469                                                    ObjectIdGetDatum(funcoid),
 470                                                    0, 0, 0);
 471         if (!HeapTupleIsValid(tuple))
 472                 elog(ERROR, "cache lookup failed for function %u", funcoid);
 473         proc = (Form_pg_proc) GETSTRUCT(tuple);
 474
 475         functyptype = get_typtype(proc->prorettype);
 476
 477         /* Disallow pseudotype result */
 478         /* except for RECORD, VOID, ANYARRAY, or ANYELEMENT */
 479         if (functyptype == 'p' &&
 480                 proc->prorettype != RECORDOID &&
 481                 proc->prorettype != VOIDOID &&
 482                 proc->prorettype != ANYARRAYOID &&
 483                 proc->prorettype != ANYELEMENTOID)
 484                 ereport(ERROR,
 485                                 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
 486                                  errmsg("SQL functions cannot return type %s",
 487                                                 format_type_be(proc->prorettype))));
 488
 489         /* Disallow pseudotypes in arguments */
 490         /* except for ANYARRAY or ANYELEMENT */
 491         haspolyarg = false;
 492         for (i = 0; i < proc->pronargs; i++)
 493         {
 494                 if (get_typtype(proc->proargtypes.values[i]) == 'p')
 495                 {
 496                         if (proc->proargtypes.values[i] == ANYARRAYOID ||
 497                                 proc->proargtypes.values[i] == ANYELEMENTOID)
 498                                 haspolyarg = true;
 499                         else
 500                                 ereport(ERROR,
 501                                                 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
 502                                  errmsg("SQL functions cannot have arguments of type %s",
 503                                                 format_type_be(proc->proargtypes.values[i]))));
 504                 }
 505         }
 506
 507         /* Postpone body checks if !check_function_bodies */
 508         if (check_function_bodies)
 509         {
 510                 tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_prosrc, &isnull);
 511                 if (isnull)
 512                         elog(ERROR, "null prosrc");
 513
 514                 prosrc = DatumGetCString(DirectFunctionCall1(textout, tmp));
 515
 516                 /*
 517                  * Setup error traceback support for ereport().
 518                  */
 519                 sqlerrcontext.callback = sql_function_parse_error_callback;
 520                 sqlerrcontext.arg = tuple;
 521                 sqlerrcontext.previous = error_context_stack;
 522                 error_context_stack = &sqlerrcontext;
 523
 524                 /*
 525                  * We can't do full prechecking of the function definition if
 526                  * there are any polymorphic input types, because actual datatypes
 527                  * of expression results will be unresolvable.  The check will be
 528                  * done at runtime instead.
 529                  *
 530                  * We can run the text through the raw parser though; this will at
 531                  * least catch silly syntactic errors.
 532                  */
 533                 if (!haspolyarg)
 534                 {
 535                         querytree_list = pg_parse_and_rewrite(prosrc,
 536                                                                                                   proc->proargtypes.values,
 537                                                                                                   proc->pronargs);
 538                         (void) check_sql_fn_retval(proc->prorettype, functyptype,
 539                                                                            querytree_list, NULL);
 540                 }
 541                 else
 542                         querytree_list = pg_parse_query(prosrc);
 543
 544                 error_context_stack = sqlerrcontext.previous;
 545         }
 546
 547         ReleaseSysCache(tuple);
 548
 549         PG_RETURN_VOID();
 550 }
 551
 552 /*
 553  * Error context callback for handling errors in SQL function definitions
 554  */
 555 static void
 556 sql_function_parse_error_callback(void *arg)
 557 {
 558         HeapTuple       tuple = (HeapTuple) arg;
 559         Form_pg_proc proc = (Form_pg_proc) GETSTRUCT(tuple);
 560         bool            isnull;
 561         Datum           tmp;
 562         char       *prosrc;
 563
 564         /* See if it's a syntax error; if so, transpose to CREATE FUNCTION */
 565         tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_prosrc, &isnull);
 566         if (isnull)
 567                 elog(ERROR, "null prosrc");
 568         prosrc = DatumGetCString(DirectFunctionCall1(textout, tmp));
 569
 570         if (!function_parse_error_transpose(prosrc))
 571         {
 572                 /* If it's not a syntax error, push info onto context stack */
 573                 errcontext("SQL function \"%s\"", NameStr(proc->proname));
 574         }
 575
 576         pfree(prosrc);
 577 }
 578
 579 /*
 580  * Adjust a syntax error occurring inside the function body of a CREATE
 581  * FUNCTION command.  This can be used by any function validator, not only
 582  * for SQL-language functions.  It is assumed that the syntax error position
 583  * is initially relative to the function body string (as passed in).  If
 584  * possible, we adjust the position to reference the original CREATE command;
 585  * if we can't manage that, we set up an "internal query" syntax error instead.
 586  *
 587  * Returns true if a syntax error was processed, false if not.
 588  */
 589 bool
 590 function_parse_error_transpose(const char *prosrc)
 591 {
 592         int                     origerrposition;
 593         int                     newerrposition;
 594         const char *queryText;
 595
 596         /*
 597          * Nothing to do unless we are dealing with a syntax error that has a
 598          * cursor position.
 599          *
 600          * Some PLs may prefer to report the error position as an internal error
 601          * to begin with, so check that too.
 602          */
 603         origerrposition = geterrposition();
 604         if (origerrposition <= 0)
 605         {
 606                 origerrposition = getinternalerrposition();
 607                 if (origerrposition <= 0)
 608                         return false;
 609         }
 610
 611         /* We can get the original query text from the active portal (hack...) */
 612         Assert(ActivePortal && ActivePortal->status == PORTAL_ACTIVE);
 613         queryText = ActivePortal->sourceText;
 614
 615         /* Try to locate the prosrc in the original text */
 616         newerrposition = match_prosrc_to_query(prosrc, queryText, origerrposition);
 617
 618         if (newerrposition > 0)
 619         {
 620                 /* Successful, so fix error position to reference original query */
 621                 errposition(newerrposition);
 622                 /* Get rid of any report of the error as an "internal query" */
 623                 internalerrposition(0);
 624                 internalerrquery(NULL);
 625         }
 626         else
 627         {
 628                 /*
 629                  * If unsuccessful, convert the position to an internal position
 630                  * marker and give the function text as the internal query.
 631                  */
 632                 errposition(0);
 633                 internalerrposition(origerrposition);
 634                 internalerrquery(prosrc);
 635         }
 636
 637         return true;
 638 }
 639
 640 /*
 641  * Try to locate the string literal containing the function body in the
 642  * given text of the CREATE FUNCTION command.  If successful, return the
 643  * character (not byte) index within the command corresponding to the
 644  * given character index within the literal.  If not successful, return 0.
 645  */
 646 static int
 647 match_prosrc_to_query(const char *prosrc, const char *queryText,
 648                                           int cursorpos)
 649 {
 650         /*
 651          * Rather than fully parsing the CREATE FUNCTION command, we just scan
 652          * the command looking for $prosrc$ or 'prosrc'.  This could be fooled
 653          * (though not in any very probable scenarios), so fail if we find
 654          * more than one match.
 655          */
 656         int                     prosrclen = strlen(prosrc);
 657         int                     querylen = strlen(queryText);
 658         int                     matchpos = 0;
 659         int                     curpos;
 660         int                     newcursorpos;
 661
 662         for (curpos = 0; curpos < querylen - prosrclen; curpos++)
 663         {
 664                 if (queryText[curpos] == '$' &&
 665                         strncmp(prosrc, &queryText[curpos + 1], prosrclen) == 0 &&
 666                         queryText[curpos + 1 + prosrclen] == '$')
 667                 {
 668                         /*
 669                          * Found a $foo$ match.  Since there are no embedded quoting
 670                          * characters in a dollar-quoted literal, we don't have to do
 671                          * any fancy arithmetic; just offset by the starting position.
 672                          */
 673                         if (matchpos)
 674                                 return 0;               /* multiple matches, fail */
 675                         matchpos = pg_mbstrlen_with_len(queryText, curpos + 1)
 676                                 + cursorpos;
 677                 }
 678                 else if (queryText[curpos] == '\'' &&
 679                                  match_prosrc_to_literal(prosrc, &queryText[curpos + 1],
 680                                                                                  cursorpos, &newcursorpos))
 681                 {
 682                         /*
 683                          * Found a 'foo' match.  match_prosrc_to_literal() has
 684                          * adjusted for any quotes or backslashes embedded in the
 685                          * literal.
 686                          */
 687                         if (matchpos)
 688                                 return 0;               /* multiple matches, fail */
 689                         matchpos = pg_mbstrlen_with_len(queryText, curpos + 1)
 690                                 + newcursorpos;
 691                 }
 692         }
 693
 694         return matchpos;
 695 }
 696
 697 /*
 698  * Try to match the given source text to a single-quoted literal.
 699  * If successful, adjust newcursorpos to correspond to the character
 700  * (not byte) index corresponding to cursorpos in the source text.
 701  *
 702  * At entry, literal points just past a ' character.  We must check for the
 703  * trailing quote.
 704  */
 705 static bool
 706 match_prosrc_to_literal(const char *prosrc, const char *literal,
 707                                                 int cursorpos, int *newcursorpos)
 708 {
 709         int                     newcp = cursorpos;
 710         int                     chlen;
 711
 712         /*
 713          * This implementation handles backslashes and doubled quotes in the
 714          * string literal.      It does not handle the SQL syntax for literals
 715          * continued across line boundaries.
 716          *
 717          * We do the comparison a character at a time, not a byte at a time, so
 718          * that we can do the correct cursorpos math.
 719          */
 720         while (*prosrc)
 721         {
 722                 cursorpos--;                    /* characters left before cursor */
 723
 724                 /*
 725                  * Check for backslashes and doubled quotes in the literal; adjust
 726                  * newcp when one is found before the cursor.
 727                  */
 728                 if (*literal == '\\')
 729                 {
 730                         literal++;
 731                         if (cursorpos > 0)
 732                                 newcp++;
 733                 }
 734                 else if (*literal == '\'')
 735                 {
 736                         if (literal[1] != '\'')
 737                                 return false;
 738                         literal++;
 739                         if (cursorpos > 0)
 740                                 newcp++;
 741                 }
 742                 chlen = pg_mblen(prosrc);
 743                 if (strncmp(prosrc, literal, chlen) != 0)
 744                         return false;
 745                 prosrc += chlen;
 746                 literal += chlen;
 747         }
 748
 749         *newcursorpos = newcp;
 750
 751         if (*literal == '\'' && literal[1] != '\'')
 752                 return true;
 753         return false;
 754 }