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Sourcecode: postgresql-8.4 version File versions

pg_proc.c

/*-------------------------------------------------------------------------
 *
 * pg_proc.c
 *      routines to support manipulation of the pg_proc relation
 *
 * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *      $PostgreSQL: pgsql/src/backend/catalog/pg_proc.c,v 1.164 2009/06/11 14:48:55 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include "access/heapam.h"
#include "access/xact.h"
#include "catalog/dependency.h"
#include "catalog/indexing.h"
#include "catalog/pg_language.h"
#include "catalog/pg_namespace.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_proc_fn.h"
#include "catalog/pg_type.h"
#include "executor/functions.h"
#include "funcapi.h"
#include "mb/pg_wchar.h"
#include "miscadmin.h"
#include "nodes/nodeFuncs.h"
#include "parser/parse_type.h"
#include "tcop/pquery.h"
#include "tcop/tcopprot.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"


Datum       fmgr_internal_validator(PG_FUNCTION_ARGS);
Datum       fmgr_c_validator(PG_FUNCTION_ARGS);
Datum       fmgr_sql_validator(PG_FUNCTION_ARGS);

static void sql_function_parse_error_callback(void *arg);
static int match_prosrc_to_query(const char *prosrc, const char *queryText,
                                int cursorpos);
static bool match_prosrc_to_literal(const char *prosrc, const char *literal,
                                    int cursorpos, int *newcursorpos);


/* ----------------------------------------------------------------
 *          ProcedureCreate
 *
 * Note: allParameterTypes, parameterModes, parameterNames, and proconfig
 * are either arrays of the proper types or NULL.  We declare them Datum,
 * not "ArrayType *", to avoid importing array.h into pg_proc_fn.h.
 * ----------------------------------------------------------------
 */
Oid
ProcedureCreate(const char *procedureName,
                        Oid procNamespace,
                        bool replace,
                        bool returnsSet,
                        Oid returnType,
                        Oid languageObjectId,
                        Oid languageValidator,
                        const char *prosrc,
                        const char *probin,
                        bool isAgg,
                        bool isWindowFunc,
                        bool security_definer,
                        bool isStrict,
                        char volatility,
                        oidvector *parameterTypes,
                        Datum allParameterTypes,
                        Datum parameterModes,
                        Datum parameterNames,
                        List *parameterDefaults,
                        Datum proconfig,
                        float4 procost,
                        float4 prorows)
{
      Oid               retval;
      int               parameterCount;
      int               allParamCount;
      Oid            *allParams;
      bool        genericInParam = false;
      bool        genericOutParam = false;
      bool        internalInParam = false;
      bool        internalOutParam = false;
      Oid               variadicType = InvalidOid;
      Relation    rel;
      HeapTuple   tup;
      HeapTuple   oldtup;
      bool        nulls[Natts_pg_proc];
      Datum       values[Natts_pg_proc];
      bool        replaces[Natts_pg_proc];
      Oid               relid;
      NameData    procname;
      TupleDesc   tupDesc;
      bool        is_update;
      ObjectAddress myself,
                        referenced;
      int               i;

      /*
       * sanity checks
       */
      Assert(PointerIsValid(prosrc));

      parameterCount = parameterTypes->dim1;
      if (parameterCount < 0 || parameterCount > FUNC_MAX_ARGS)
            ereport(ERROR,
                        (errcode(ERRCODE_TOO_MANY_ARGUMENTS),
                         errmsg_plural("functions cannot have more than %d argument",
                                             "functions cannot have more than %d arguments",
                                             FUNC_MAX_ARGS,
                                             FUNC_MAX_ARGS)));
      /* note: the above is correct, we do NOT count output arguments */

      if (allParameterTypes != PointerGetDatum(NULL))
      {
            /*
             * We expect the array to be a 1-D OID array; verify that. We don't
             * need to use deconstruct_array() since the array data is just going
             * to look like a C array of OID values.
             */
            ArrayType  *allParamArray = (ArrayType *) DatumGetPointer(allParameterTypes);

            allParamCount = ARR_DIMS(allParamArray)[0];
            if (ARR_NDIM(allParamArray) != 1 ||
                  allParamCount <= 0 ||
                  ARR_HASNULL(allParamArray) ||
                  ARR_ELEMTYPE(allParamArray) != OIDOID)
                  elog(ERROR, "allParameterTypes is not a 1-D Oid array");
            allParams = (Oid *) ARR_DATA_PTR(allParamArray);
            Assert(allParamCount >= parameterCount);
            /* we assume caller got the contents right */
      }
      else
      {
            allParamCount = parameterCount;
            allParams = parameterTypes->values;
      }

      /*
       * Do not allow polymorphic return type unless at least one input argument
       * is polymorphic.      Also, do not allow return type INTERNAL unless at
       * least one input argument is INTERNAL.
       */
      for (i = 0; i < parameterCount; i++)
      {
            switch (parameterTypes->values[i])
            {
                  case ANYARRAYOID:
                  case ANYELEMENTOID:
                  case ANYNONARRAYOID:
                  case ANYENUMOID:
                        genericInParam = true;
                        break;
                  case INTERNALOID:
                        internalInParam = true;
                        break;
            }
      }

      if (allParameterTypes != PointerGetDatum(NULL))
      {
            for (i = 0; i < allParamCount; i++)
            {
                  /*
                   * We don't bother to distinguish input and output params here, so
                   * if there is, say, just an input INTERNAL param then we will
                   * still set internalOutParam.      This is OK since we don't really
                   * care.
                   */
                  switch (allParams[i])
                  {
                        case ANYARRAYOID:
                        case ANYELEMENTOID:
                        case ANYNONARRAYOID:
                        case ANYENUMOID:
                              genericOutParam = true;
                              break;
                        case INTERNALOID:
                              internalOutParam = true;
                              break;
                  }
            }
      }

      if ((IsPolymorphicType(returnType) || genericOutParam)
            && !genericInParam)
            ereport(ERROR,
                        (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
                         errmsg("cannot determine result data type"),
                         errdetail("A function returning a polymorphic type must have at least one polymorphic argument.")));

      if ((returnType == INTERNALOID || internalOutParam) && !internalInParam)
            ereport(ERROR,
                        (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
                         errmsg("unsafe use of pseudo-type \"internal\""),
                         errdetail("A function returning \"internal\" must have at least one \"internal\" argument.")));

      /*
       * don't allow functions of complex types that have the same name as
       * existing attributes of the type
       */
      if (parameterCount == 1 &&
            OidIsValid(parameterTypes->values[0]) &&
            (relid = typeidTypeRelid(parameterTypes->values[0])) != InvalidOid &&
            get_attnum(relid, procedureName) != InvalidAttrNumber)
            ereport(ERROR,
                        (errcode(ERRCODE_DUPLICATE_COLUMN),
                         errmsg("\"%s\" is already an attribute of type %s",
                                    procedureName,
                                    format_type_be(parameterTypes->values[0]))));

      if (parameterModes != PointerGetDatum(NULL))
      {
            /*
             * We expect the array to be a 1-D CHAR array; verify that. We don't
             * need to use deconstruct_array() since the array data is just going
             * to look like a C array of char values.
             */
            ArrayType  *modesArray = (ArrayType *) DatumGetPointer(parameterModes);
            char     *modes;

            if (ARR_NDIM(modesArray) != 1 ||
                  ARR_DIMS(modesArray)[0] != allParamCount ||
                  ARR_HASNULL(modesArray) ||
                  ARR_ELEMTYPE(modesArray) != CHAROID)
                  elog(ERROR, "parameterModes is not a 1-D char array");
            modes = (char *) ARR_DATA_PTR(modesArray);

            /*
             * Only the last input parameter can be variadic; if it is, save its
             * element type.  Errors here are just elog since caller should have
             * checked this already.
             */
            for (i = 0; i < allParamCount; i++)
            {
                  switch (modes[i])
                  {
                        case PROARGMODE_IN:
                        case PROARGMODE_INOUT:
                              if (OidIsValid(variadicType))
                                    elog(ERROR, "variadic parameter must be last");
                              break;
                        case PROARGMODE_OUT:
                        case PROARGMODE_TABLE:
                              /* okay */
                              break;
                        case PROARGMODE_VARIADIC:
                              if (OidIsValid(variadicType))
                                    elog(ERROR, "variadic parameter must be last");
                              switch (allParams[i])
                              {
                                    case ANYOID:
                                          variadicType = ANYOID;
                                          break;
                                    case ANYARRAYOID:
                                          variadicType = ANYELEMENTOID;
                                          break;
                                    default:
                                          variadicType = get_element_type(allParams[i]);
                                          if (!OidIsValid(variadicType))
                                                elog(ERROR, "variadic parameter is not an array");
                                          break;
                              }
                              break;
                        default:
                              elog(ERROR, "invalid parameter mode '%c'", modes[i]);
                              break;
                  }
            }
      }

      /*
       * All seems OK; prepare the data to be inserted into pg_proc.
       */

      for (i = 0; i < Natts_pg_proc; ++i)
      {
            nulls[i] = false;
            values[i] = (Datum) 0;
            replaces[i] = true;
      }

      namestrcpy(&procname, procedureName);
      values[Anum_pg_proc_proname - 1] = NameGetDatum(&procname);
      values[Anum_pg_proc_pronamespace - 1] = ObjectIdGetDatum(procNamespace);
      values[Anum_pg_proc_proowner - 1] = ObjectIdGetDatum(GetUserId());
      values[Anum_pg_proc_prolang - 1] = ObjectIdGetDatum(languageObjectId);
      values[Anum_pg_proc_procost - 1] = Float4GetDatum(procost);
      values[Anum_pg_proc_prorows - 1] = Float4GetDatum(prorows);
      values[Anum_pg_proc_provariadic - 1] = ObjectIdGetDatum(variadicType);
      values[Anum_pg_proc_proisagg - 1] = BoolGetDatum(isAgg);
      values[Anum_pg_proc_proiswindow - 1] = BoolGetDatum(isWindowFunc);
      values[Anum_pg_proc_prosecdef - 1] = BoolGetDatum(security_definer);
      values[Anum_pg_proc_proisstrict - 1] = BoolGetDatum(isStrict);
      values[Anum_pg_proc_proretset - 1] = BoolGetDatum(returnsSet);
      values[Anum_pg_proc_provolatile - 1] = CharGetDatum(volatility);
      values[Anum_pg_proc_pronargs - 1] = UInt16GetDatum(parameterCount);
      values[Anum_pg_proc_pronargdefaults - 1] = UInt16GetDatum(list_length(parameterDefaults));
      values[Anum_pg_proc_prorettype - 1] = ObjectIdGetDatum(returnType);
      values[Anum_pg_proc_proargtypes - 1] = PointerGetDatum(parameterTypes);
      if (allParameterTypes != PointerGetDatum(NULL))
            values[Anum_pg_proc_proallargtypes - 1] = allParameterTypes;
      else
            nulls[Anum_pg_proc_proallargtypes - 1] = true;
      if (parameterModes != PointerGetDatum(NULL))
            values[Anum_pg_proc_proargmodes - 1] = parameterModes;
      else
            nulls[Anum_pg_proc_proargmodes - 1] = true;
      if (parameterNames != PointerGetDatum(NULL))
            values[Anum_pg_proc_proargnames - 1] = parameterNames;
      else
            nulls[Anum_pg_proc_proargnames - 1] = true;
      if (parameterDefaults != NIL)
            values[Anum_pg_proc_proargdefaults - 1] = CStringGetTextDatum(nodeToString(parameterDefaults));
      else
            nulls[Anum_pg_proc_proargdefaults - 1] = true;
      values[Anum_pg_proc_prosrc - 1] = CStringGetTextDatum(prosrc);
      if (probin)
            values[Anum_pg_proc_probin - 1] = CStringGetTextDatum(probin);
      else
            nulls[Anum_pg_proc_probin - 1] = true;
      if (proconfig != PointerGetDatum(NULL))
            values[Anum_pg_proc_proconfig - 1] = proconfig;
      else
            nulls[Anum_pg_proc_proconfig - 1] = true;
      /* start out with empty permissions */
      nulls[Anum_pg_proc_proacl - 1] = true;

      rel = heap_open(ProcedureRelationId, RowExclusiveLock);
      tupDesc = RelationGetDescr(rel);

      /* Check for pre-existing definition */
      oldtup = SearchSysCache(PROCNAMEARGSNSP,
                                          PointerGetDatum(procedureName),
                                          PointerGetDatum(parameterTypes),
                                          ObjectIdGetDatum(procNamespace),
                                          0);

      if (HeapTupleIsValid(oldtup))
      {
            /* There is one; okay to replace it? */
            Form_pg_proc oldproc = (Form_pg_proc) GETSTRUCT(oldtup);

            if (!replace)
                  ereport(ERROR,
                              (errcode(ERRCODE_DUPLICATE_FUNCTION),
                  errmsg("function \"%s\" already exists with same argument types",
                           procedureName)));
            if (!pg_proc_ownercheck(HeapTupleGetOid(oldtup), GetUserId()))
                  aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_PROC,
                                       procedureName);

            /*
             * Not okay to change the return type of the existing proc, since
             * existing rules, views, etc may depend on the return type.
             */
            if (returnType != oldproc->prorettype ||
                  returnsSet != oldproc->proretset)
                  ereport(ERROR,
                              (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
                               errmsg("cannot change return type of existing function"),
                               errhint("Use DROP FUNCTION first.")));

            /*
             * If it returns RECORD, check for possible change of record type
             * implied by OUT parameters
             */
            if (returnType == RECORDOID)
            {
                  TupleDesc   olddesc;
                  TupleDesc   newdesc;

                  olddesc = build_function_result_tupdesc_t(oldtup);
                  newdesc = build_function_result_tupdesc_d(allParameterTypes,
                                                                                parameterModes,
                                                                                parameterNames);
                  if (olddesc == NULL && newdesc == NULL)
                         /* ok, both are runtime-defined RECORDs */ ;
                  else if (olddesc == NULL || newdesc == NULL ||
                               !equalTupleDescs(olddesc, newdesc))
                        ereport(ERROR,
                                    (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
                              errmsg("cannot change return type of existing function"),
                        errdetail("Row type defined by OUT parameters is different."),
                                     errhint("Use DROP FUNCTION first.")));
            }

            /*
             * If there are existing defaults, check compatibility: redefinition
             * must not remove any defaults nor change their types.  (Removing a
             * default might cause a function to fail to satisfy an existing call.
             * Changing type would only be possible if the associated parameter is
             * polymorphic, and in such cases a change of default type might alter
             * the resolved output type of existing calls.)
             */
            if (oldproc->pronargdefaults != 0)
            {
                  Datum       proargdefaults;
                  bool        isnull;
                  List     *oldDefaults;
                  ListCell   *oldlc;
                  ListCell   *newlc;

                  if (list_length(parameterDefaults) < oldproc->pronargdefaults)
                        ereport(ERROR,
                                    (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
                                     errmsg("cannot remove parameter defaults from existing function"),
                                     errhint("Use DROP FUNCTION first.")));

                  proargdefaults = SysCacheGetAttr(PROCNAMEARGSNSP, oldtup,
                                                                   Anum_pg_proc_proargdefaults,
                                                                   &isnull);
                  Assert(!isnull);
                  oldDefaults = (List *) stringToNode(TextDatumGetCString(proargdefaults));
                  Assert(IsA(oldDefaults, List));
                  Assert(list_length(oldDefaults) == oldproc->pronargdefaults);

                  /* new list can have more defaults than old, advance over 'em */
                  newlc = list_head(parameterDefaults);
                  for (i = list_length(parameterDefaults) - oldproc->pronargdefaults;
                         i > 0;
                         i--)
                        newlc = lnext(newlc);

                  foreach(oldlc, oldDefaults)
                  {
                        Node     *oldDef = (Node *) lfirst(oldlc);
                        Node     *newDef = (Node *) lfirst(newlc);

                        if (exprType(oldDef) != exprType(newDef))
                              ereport(ERROR,
                                          (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
                                           errmsg("cannot change data type of existing parameter default value"),
                                           errhint("Use DROP FUNCTION first.")));
                        newlc = lnext(newlc);
                  }
            }

            /* Can't change aggregate or window-function status, either */
            if (oldproc->proisagg != isAgg)
            {
                  if (oldproc->proisagg)
                        ereport(ERROR,
                                    (errcode(ERRCODE_WRONG_OBJECT_TYPE),
                                     errmsg("function \"%s\" is an aggregate function",
                                                procedureName)));
                  else
                        ereport(ERROR,
                                    (errcode(ERRCODE_WRONG_OBJECT_TYPE),
                                 errmsg("function \"%s\" is not an aggregate function",
                                            procedureName)));
            }
            if (oldproc->proiswindow != isWindowFunc)
            {
                  if (oldproc->proiswindow)
                        ereport(ERROR,
                                    (errcode(ERRCODE_WRONG_OBJECT_TYPE),
                                     errmsg("function \"%s\" is a window function",
                                                procedureName)));
                  else
                        ereport(ERROR,
                                    (errcode(ERRCODE_WRONG_OBJECT_TYPE),
                                     errmsg("function \"%s\" is not a window function",
                                                procedureName)));
            }

            /* do not change existing ownership or permissions, either */
            replaces[Anum_pg_proc_proowner - 1] = false;
            replaces[Anum_pg_proc_proacl - 1] = false;

            /* Okay, do it... */
            tup = heap_modify_tuple(oldtup, tupDesc, values, nulls, replaces);
            simple_heap_update(rel, &tup->t_self, tup);

            ReleaseSysCache(oldtup);
            is_update = true;
      }
      else
      {
            /* Creating a new procedure */
            tup = heap_form_tuple(tupDesc, values, nulls);
            simple_heap_insert(rel, tup);
            is_update = false;
      }

      /* Need to update indexes for either the insert or update case */
      CatalogUpdateIndexes(rel, tup);

      retval = HeapTupleGetOid(tup);

      /*
       * Create dependencies for the new function.  If we are updating an
       * existing function, first delete any existing pg_depend entries.
       */
      if (is_update)
      {
            deleteDependencyRecordsFor(ProcedureRelationId, retval);
            deleteSharedDependencyRecordsFor(ProcedureRelationId, retval, 0);
      }

      myself.classId = ProcedureRelationId;
      myself.objectId = retval;
      myself.objectSubId = 0;

      /* dependency on namespace */
      referenced.classId = NamespaceRelationId;
      referenced.objectId = procNamespace;
      referenced.objectSubId = 0;
      recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);

      /* dependency on implementation language */
      referenced.classId = LanguageRelationId;
      referenced.objectId = languageObjectId;
      referenced.objectSubId = 0;
      recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);

      /* dependency on return type */
      referenced.classId = TypeRelationId;
      referenced.objectId = returnType;
      referenced.objectSubId = 0;
      recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);

      /* dependency on parameter types */
      for (i = 0; i < allParamCount; i++)
      {
            referenced.classId = TypeRelationId;
            referenced.objectId = allParams[i];
            referenced.objectSubId = 0;
            recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
      }

      /* dependency on owner */
      recordDependencyOnOwner(ProcedureRelationId, retval, GetUserId());

      heap_freetuple(tup);

      heap_close(rel, RowExclusiveLock);

      /* Verify function body */
      if (OidIsValid(languageValidator))
      {
            /* Advance command counter so new tuple can be seen by validator */
            CommandCounterIncrement();
            OidFunctionCall1(languageValidator, ObjectIdGetDatum(retval));
      }

      return retval;
}



/*
 * Validator for internal functions
 *
 * Check that the given internal function name (the "prosrc" value) is
 * a known builtin function.
 */
Datum
fmgr_internal_validator(PG_FUNCTION_ARGS)
{
      Oid               funcoid = PG_GETARG_OID(0);
      HeapTuple   tuple;
      Form_pg_proc proc;
      bool        isnull;
      Datum       tmp;
      char     *prosrc;

      /*
       * We do not honor check_function_bodies since it's unlikely the function
       * name will be found later if it isn't there now.
       */

      tuple = SearchSysCache(PROCOID,
                                       ObjectIdGetDatum(funcoid),
                                       0, 0, 0);
      if (!HeapTupleIsValid(tuple))
            elog(ERROR, "cache lookup failed for function %u", funcoid);
      proc = (Form_pg_proc) GETSTRUCT(tuple);

      tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_prosrc, &isnull);
      if (isnull)
            elog(ERROR, "null prosrc");
      prosrc = TextDatumGetCString(tmp);

      if (fmgr_internal_function(prosrc) == InvalidOid)
            ereport(ERROR,
                        (errcode(ERRCODE_UNDEFINED_FUNCTION),
                         errmsg("there is no built-in function named \"%s\"",
                                    prosrc)));

      ReleaseSysCache(tuple);

      PG_RETURN_VOID();
}



/*
 * Validator for C language functions
 *
 * Make sure that the library file exists, is loadable, and contains
 * the specified link symbol. Also check for a valid function
 * information record.
 */
Datum
fmgr_c_validator(PG_FUNCTION_ARGS)
{
      Oid               funcoid = PG_GETARG_OID(0);
      void     *libraryhandle;
      HeapTuple   tuple;
      Form_pg_proc proc;
      bool        isnull;
      Datum       tmp;
      char     *prosrc;
      char     *probin;

      /*
       * It'd be most consistent to skip the check if !check_function_bodies,
       * but the purpose of that switch is to be helpful for pg_dump loading,
       * and for pg_dump loading it's much better if we *do* check.
       */

      tuple = SearchSysCache(PROCOID,
                                       ObjectIdGetDatum(funcoid),
                                       0, 0, 0);
      if (!HeapTupleIsValid(tuple))
            elog(ERROR, "cache lookup failed for function %u", funcoid);
      proc = (Form_pg_proc) GETSTRUCT(tuple);

      tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_prosrc, &isnull);
      if (isnull)
            elog(ERROR, "null prosrc for C function %u", funcoid);
      prosrc = TextDatumGetCString(tmp);

      tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_probin, &isnull);
      if (isnull)
            elog(ERROR, "null probin for C function %u", funcoid);
      probin = TextDatumGetCString(tmp);

      (void) load_external_function(probin, prosrc, true, &libraryhandle);
      (void) fetch_finfo_record(libraryhandle, prosrc);

      ReleaseSysCache(tuple);

      PG_RETURN_VOID();
}


/*
 * Validator for SQL language functions
 *
 * Parse it here in order to be sure that it contains no syntax errors.
 */
Datum
fmgr_sql_validator(PG_FUNCTION_ARGS)
{
      Oid               funcoid = PG_GETARG_OID(0);
      HeapTuple   tuple;
      Form_pg_proc proc;
      List     *querytree_list;
      bool        isnull;
      Datum       tmp;
      char     *prosrc;
      ErrorContextCallback sqlerrcontext;
      bool        haspolyarg;
      int               i;

      tuple = SearchSysCache(PROCOID,
                                       ObjectIdGetDatum(funcoid),
                                       0, 0, 0);
      if (!HeapTupleIsValid(tuple))
            elog(ERROR, "cache lookup failed for function %u", funcoid);
      proc = (Form_pg_proc) GETSTRUCT(tuple);

      /* Disallow pseudotype result */
      /* except for RECORD, VOID, or polymorphic */
      if (get_typtype(proc->prorettype) == TYPTYPE_PSEUDO &&
            proc->prorettype != RECORDOID &&
            proc->prorettype != VOIDOID &&
            !IsPolymorphicType(proc->prorettype))
            ereport(ERROR,
                        (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
                         errmsg("SQL functions cannot return type %s",
                                    format_type_be(proc->prorettype))));

      /* Disallow pseudotypes in arguments */
      /* except for polymorphic */
      haspolyarg = false;
      for (i = 0; i < proc->pronargs; i++)
      {
            if (get_typtype(proc->proargtypes.values[i]) == TYPTYPE_PSEUDO)
            {
                  if (IsPolymorphicType(proc->proargtypes.values[i]))
                        haspolyarg = true;
                  else
                        ereport(ERROR,
                                    (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
                               errmsg("SQL functions cannot have arguments of type %s",
                                          format_type_be(proc->proargtypes.values[i]))));
            }
      }

      /* Postpone body checks if !check_function_bodies */
      if (check_function_bodies)
      {
            tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_prosrc, &isnull);
            if (isnull)
                  elog(ERROR, "null prosrc");

            prosrc = TextDatumGetCString(tmp);

            /*
             * Setup error traceback support for ereport().
             */
            sqlerrcontext.callback = sql_function_parse_error_callback;
            sqlerrcontext.arg = tuple;
            sqlerrcontext.previous = error_context_stack;
            error_context_stack = &sqlerrcontext;

            /*
             * We can't do full prechecking of the function definition if there
             * are any polymorphic input types, because actual datatypes of
             * expression results will be unresolvable.  The check will be done at
             * runtime instead.
             *
             * We can run the text through the raw parser though; this will at
             * least catch silly syntactic errors.
             */
            if (!haspolyarg)
            {
                  querytree_list = pg_parse_and_rewrite(prosrc,
                                                                          proc->proargtypes.values,
                                                                          proc->pronargs);
                  (void) check_sql_fn_retval(funcoid, proc->prorettype,
                                                         querytree_list,
                                                         false, NULL);
            }
            else
                  querytree_list = pg_parse_query(prosrc);

            error_context_stack = sqlerrcontext.previous;
      }

      ReleaseSysCache(tuple);

      PG_RETURN_VOID();
}

/*
 * Error context callback for handling errors in SQL function definitions
 */
static void
sql_function_parse_error_callback(void *arg)
{
      HeapTuple   tuple = (HeapTuple) arg;
      Form_pg_proc proc = (Form_pg_proc) GETSTRUCT(tuple);
      bool        isnull;
      Datum       tmp;
      char     *prosrc;

      /* See if it's a syntax error; if so, transpose to CREATE FUNCTION */
      tmp = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_prosrc, &isnull);
      if (isnull)
            elog(ERROR, "null prosrc");
      prosrc = TextDatumGetCString(tmp);

      if (!function_parse_error_transpose(prosrc))
      {
            /* If it's not a syntax error, push info onto context stack */
            errcontext("SQL function \"%s\"", NameStr(proc->proname));
      }

      pfree(prosrc);
}

/*
 * Adjust a syntax error occurring inside the function body of a CREATE
 * FUNCTION command.  This can be used by any function validator, not only
 * for SQL-language functions.      It is assumed that the syntax error position
 * is initially relative to the function body string (as passed in).  If
 * possible, we adjust the position to reference the original CREATE command;
 * if we can't manage that, we set up an "internal query" syntax error instead.
 *
 * Returns true if a syntax error was processed, false if not.
 */
bool
function_parse_error_transpose(const char *prosrc)
{
      int               origerrposition;
      int               newerrposition;
      const char *queryText;

      /*
       * Nothing to do unless we are dealing with a syntax error that has a
       * cursor position.
       *
       * Some PLs may prefer to report the error position as an internal error
       * to begin with, so check that too.
       */
      origerrposition = geterrposition();
      if (origerrposition <= 0)
      {
            origerrposition = getinternalerrposition();
            if (origerrposition <= 0)
                  return false;
      }

      /* We can get the original query text from the active portal (hack...) */
      Assert(ActivePortal && ActivePortal->status == PORTAL_ACTIVE);
      queryText = ActivePortal->sourceText;

      /* Try to locate the prosrc in the original text */
      newerrposition = match_prosrc_to_query(prosrc, queryText, origerrposition);

      if (newerrposition > 0)
      {
            /* Successful, so fix error position to reference original query */
            errposition(newerrposition);
            /* Get rid of any report of the error as an "internal query" */
            internalerrposition(0);
            internalerrquery(NULL);
      }
      else
      {
            /*
             * If unsuccessful, convert the position to an internal position
             * marker and give the function text as the internal query.
             */
            errposition(0);
            internalerrposition(origerrposition);
            internalerrquery(prosrc);
      }

      return true;
}

/*
 * Try to locate the string literal containing the function body in the
 * given text of the CREATE FUNCTION command.  If successful, return the
 * character (not byte) index within the command corresponding to the
 * given character index within the literal.  If not successful, return 0.
 */
static int
match_prosrc_to_query(const char *prosrc, const char *queryText,
                                int cursorpos)
{
      /*
       * Rather than fully parsing the CREATE FUNCTION command, we just scan the
       * command looking for $prosrc$ or 'prosrc'.  This could be fooled (though
       * not in any very probable scenarios), so fail if we find more than one
       * match.
       */
      int               prosrclen = strlen(prosrc);
      int               querylen = strlen(queryText);
      int               matchpos = 0;
      int               curpos;
      int               newcursorpos;

      for (curpos = 0; curpos < querylen - prosrclen; curpos++)
      {
            if (queryText[curpos] == '$' &&
                  strncmp(prosrc, &queryText[curpos + 1], prosrclen) == 0 &&
                  queryText[curpos + 1 + prosrclen] == '$')
            {
                  /*
                   * Found a $foo$ match.  Since there are no embedded quoting
                   * characters in a dollar-quoted literal, we don't have to do any
                   * fancy arithmetic; just offset by the starting position.
                   */
                  if (matchpos)
                        return 0;         /* multiple matches, fail */
                  matchpos = pg_mbstrlen_with_len(queryText, curpos + 1)
                        + cursorpos;
            }
            else if (queryText[curpos] == '\'' &&
                         match_prosrc_to_literal(prosrc, &queryText[curpos + 1],
                                                             cursorpos, &newcursorpos))
            {
                  /*
                   * Found a 'foo' match.  match_prosrc_to_literal() has adjusted
                   * for any quotes or backslashes embedded in the literal.
                   */
                  if (matchpos)
                        return 0;         /* multiple matches, fail */
                  matchpos = pg_mbstrlen_with_len(queryText, curpos + 1)
                        + newcursorpos;
            }
      }

      return matchpos;
}

/*
 * Try to match the given source text to a single-quoted literal.
 * If successful, adjust newcursorpos to correspond to the character
 * (not byte) index corresponding to cursorpos in the source text.
 *
 * At entry, literal points just past a ' character.  We must check for the
 * trailing quote.
 */
static bool
match_prosrc_to_literal(const char *prosrc, const char *literal,
                                    int cursorpos, int *newcursorpos)
{
      int               newcp = cursorpos;
      int               chlen;

      /*
       * This implementation handles backslashes and doubled quotes in the
       * string literal.      It does not handle the SQL syntax for literals
       * continued across line boundaries.
       *
       * We do the comparison a character at a time, not a byte at a time, so
       * that we can do the correct cursorpos math.
       */
      while (*prosrc)
      {
            cursorpos--;                  /* characters left before cursor */

            /*
             * Check for backslashes and doubled quotes in the literal; adjust
             * newcp when one is found before the cursor.
             */
            if (*literal == '\\')
            {
                  literal++;
                  if (cursorpos > 0)
                        newcp++;
            }
            else if (*literal == '\'')
            {
                  if (literal[1] != '\'')
                        goto fail;
                  literal++;
                  if (cursorpos > 0)
                        newcp++;
            }
            chlen = pg_mblen(prosrc);
            if (strncmp(prosrc, literal, chlen) != 0)
                  goto fail;
            prosrc += chlen;
            literal += chlen;
      }

      if (*literal == '\'' && literal[1] != '\'')
      {
            /* success */
            *newcursorpos = newcp;
            return true;
      }

fail:
      /* Must set *newcursorpos to suppress compiler warning */
      *newcursorpos = newcp;
      return false;
}

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