text: /*-------------------------------------------------------------------------
   *
   * pg_proc.c
   *	  routines to support manipulation of the pg_proc relation
   *
   * Portions Copyright (c) 1996-2011, PostgreSQL Global Development Group
   * Portions Copyright (c) 1994, Regents of the University of California
   *
   *
   * IDENTIFICATION
   *	  src/backend/catalog/pg_proc.c
   *
   *-------------------------------------------------------------------------
   */
  #include "postgres.h"
  
  #include "access/heapam.h"
  #include "access/xact.h"
  #include "catalog/dependency.h"
  #include "catalog/indexing.h"
  #include "catalog/objectaccess.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);
  
  typedef struct
  {
  	char	   *proname;
  	char	   *prosrc;
  } parse_error_callback_arg;
  
  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;
  	Oid			proowner = GetUserId();
  	Acl		   *proacl = NULL;
  	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;
  			}
  		}
  	}
  
  	/* Guard against a case the planner doesn't handle yet */
  	if (isWindowFunc && parameterDefaults != NIL)
  		ereport(ERROR,
  				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
  				 errmsg("window functions cannot have default arguments")));
  
  	/*
  	 * 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(proowner);
  	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;
  	/* proacl will be determined later */
  
  	rel = heap_open(ProcedureRelationId, RowExclusiveLock);
  	tupDesc = RelationGetDescr(rel);
  
  	/* Check for pre-existing definition */
  	oldtup = SearchSysCache3(PROCNAMEARGSNSP,
  							 PointerGetDatum(procedureName),
  							 PointerGetDatum(parameterTypes),
  							 ObjectIdGetDatum(procNamespace));
  
  	if (HeapTupleIsValid(oldtup))
  	{
  		/* There is one; okay to replace it? */
  		Form_pg_proc oldproc = (Form_pg_proc) GETSTRUCT(oldtup);
  		Datum		proargnames;
  		bool		isnull;
  
  		if (!replace)
  			ereport(ERROR,
  					(errcode(ERRCODE_DUPLICATE_FUNCTION),
  			errmsg("function \"%s\" already exists with same argument types",
  				   procedureName)));
  		if (!pg_proc_ownercheck(HeapTupleGetOid(oldtup), proowner))
  			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 were any named input parameters, check to make sure the
  		 * names have not been changed, as this could break existing calls. We
  		 * allow adding names to formerly unnamed parameters, though.
  		 */
  		proargnames = SysCacheGetAttr(PROCNAMEARGSNSP, oldtup,
  									  Anum_pg_proc_proargnames,
  									  &isnull);
  		if (!isnull)
  		{
  			Datum		proargmodes;
  			char	  **old_arg_names;
  			char	  **new_arg_names;
  			int			n_old_arg_names;
  			int			n_new_arg_names;
  			int			j;
  
  			proargmodes = SysCacheGetAttr(PROCNAMEARGSNSP, oldtup,
  										  Anum_pg_proc_proargmodes,
  										  &isnull);
  			if (isnull)
  				proargmodes = PointerGetDatum(NULL);	/* just to be sure */
  
  			n_old_arg_names = get_func_input_arg_names(proargnames,
  													   proargmodes,
  													   &old_arg_names);
  			n_new_arg_names = get_func_input_arg_names(parameterNames,
  													   parameterModes,
  													   &new_arg_names);
  			for (j = 0; j < n_old_arg_names; j++)
  			{
  				if (old_arg_names[j] == NULL)
  					continue;
  				if (j >= n_new_arg_names || new_arg_names[j] == NULL ||
  					strcmp(old_arg_names[j], new_arg_names[j]) != 0)
  					ereport(ERROR,
  							(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
  					   errmsg("cannot change name of input parameter \"%s\"",
  							  old_arg_names[j]),
  							 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;
  			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.  Note
  		 * dependency-update code below has to agree with this decision.
  		 */
  		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 */
  
  		/* First, get default permissions and set up proacl */
  		proacl = get_user_default_acl(ACL_OBJECT_FUNCTION, proowner,
  									  procNamespace);
  		if (proacl != NULL)
  			values[Anum_pg_proc_proacl - 1] = PointerGetDatum(proacl);
  		else
  			nulls[Anum_pg_proc_proacl - 1] = true;
  
  		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.
  	 * (However, since we are not changing ownership or permissions, the
  	 * shared dependencies do *not* need to change, and we leave them alone.)
  	 */
  	if (is_update)
  		deleteDependencyRecordsFor(ProcedureRelationId, retval, true);
  
  	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 parameter default expressions */
  	if (parameterDefaults)
  		recordDependencyOnExpr(&myself, (Node *) parameterDefaults,
  							   NIL, DEPENDENCY_NORMAL);
  
  	/* dependency on owner */
  	if (!is_update)
  		recordDependencyOnOwner(ProcedureRelationId, retval, proowner);
  
  	/* dependency on any roles mentioned in ACL */
  	if (!is_update && proacl != NULL)
  	{
  		int			nnewmembers;
  		Oid		   *newmembers;
  
  		nnewmembers = aclmembers(proacl, &newmembers);
  		updateAclDependencies(ProcedureRelationId, retval, 0,
  							  proowner,
  							  0, NULL,
  							  nnewmembers, newmembers);
  	}
  
  	/* dependency on extension */
  	recordDependencyOnCurrentExtension(&myself, is_update);
  
  	heap_freetuple(tup);
  
  	/* Post creation hook for new function */
  	InvokeObjectAccessHook(OAT_POST_CREATE, ProcedureRelationId, retval, 0);
  
  	heap_close(rel, RowExclusiveLock);
  
  	/* Verify function body */
  	if (OidIsValid(languageValidator))
  	{
  		ArrayType  *set_items = NULL;
  		int			save_nestlevel = 0;
  
  		/* Advance command counter so new tuple can be seen by validator */
  		CommandCounterIncrement();
  
  		/*
  		 * Set per-function configuration parameters so that the validation is
  		 * done with the environment the function expects.  However, if
  		 * check_function_bodies is off, we don't do this, because that would
  		 * create dump ordering hazards that pg_dump doesn't know how to deal
  		 * with.  (For example, a SET clause might refer to a not-yet-created
  		 * text search configuration.)	This means that the validator
  		 * shouldn't complain about anything that might depend on a GUC
  		 * parameter when check_function_bodies is off.
  		 */
  		if (check_function_bodies)
  		{
  			set_items = (ArrayType *) DatumGetPointer(proconfig);
  			if (set_items)		/* Need a new GUC nesting level */
  			{
  				save_nestlevel = NewGUCNestLevel();
  				ProcessGUCArray(set_items,
  								(superuser() ? PGC_SUSET : PGC_USERSET),
  								PGC_S_SESSION,
  								GUC_ACTION_SAVE);
  			}
  		}
  
  		OidFunctionCall1(languageValidator, ObjectIdGetDatum(retval));
  
  		if (set_items)
  			AtEOXact_GUC(true, save_nestlevel);
  	}
  
  	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;
  	bool		isnull;
  	Datum		tmp;
  	char	   *prosrc;
  
  	if (!CheckFunctionValidatorAccess(fcinfo->flinfo->fn_oid, funcoid))
  		PG_RETURN_VOID();
  
  	/*
  	 * 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 = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcoid));
  	if (!HeapTupleIsValid(tuple))
  		elog(ERROR, "cache lookup failed for function %u", funcoid);
  
  	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;
  	bool		isnull;
  	Datum		tmp;
  	char	   *prosrc;
  	char	   *probin;
  
  	if (!CheckFunctionValidatorAccess(fcinfo->flinfo->fn_oid, funcoid))
  		PG_RETURN_VOID();
  
  	/*
  	 * 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 = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcoid));
  	if (!HeapTupleIsValid(tuple))
  		elog(ERROR, "cache lookup failed for function %u", funcoid);
  
  	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	   *raw_parsetree_list;
  	List	   *querytree_list;
  	ListCell   *lc;
  	bool		isnull;
  	Datum		tmp;
  	char	   *prosrc;
  	parse_error_callback_arg callback_arg;
  	ErrorContextCallback sqlerrcontext;
  	bool		haspolyarg;
  	int			i;
  
  	if (!CheckFunctionValidatorAccess(fcinfo->flinfo->fn_oid, funcoid))
  		PG_RETURN_VOID();
  
  	tuple = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcoid));
  	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().
  		 */
  		callback_arg.proname = NameStr(proc->proname);
  		callback_arg.prosrc = prosrc;
  
  		sqlerrcontext.callback = sql_function_parse_error_callback;
  		sqlerrcontext.arg = (void *) &callback_arg;
  		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.
  		 */
  		raw_parsetree_list = pg_parse_query(prosrc);
  
  		if (!haspolyarg)
  		{
  			/*
  			 * OK to do full precheck: analyze and rewrite the queries, then
  			 * verify the result type.
  			 */
  			SQLFunctionParseInfoPtr pinfo;
  
  			/* But first, set up parameter information */
  			pinfo = prepare_sql_fn_parse_info(tuple, NULL, InvalidOid);
  
  			querytree_list = NIL;
  			foreach(lc, raw_parsetree_list)
  			{
  				Node	   *parsetree = (Node *) lfirst(lc);
  				List	   *querytree_sublist;
  
  				querytree_sublist = pg_analyze_and_rewrite_params(parsetree,
  																  prosrc,
  									   (ParserSetupHook) sql_fn_parser_setup,
  																  pinfo);
  				querytree_list = list_concat(querytree_list,
  											 querytree_sublist);
  			}
  
  			(void) check_sql_fn_retval(funcoid, proc->prorettype,
  									   querytree_list,
  									   NULL, NULL);
  		}
  
  		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)
  {
  	parse_error_callback_arg *callback_arg = (parse_error_callback_arg *) arg;
  
  	/* See if it's a syntax error; if so, transpose to CREATE FUNCTION */
  	if (!function_parse_error_transpose(callback_arg->prosrc))
  	{
  		/* If it's not a syntax error, push info onto context stack */
  		errcontext("SQL function \"%s\"", callback_arg->proname);
  	}
  }
  
  /*
   * Adjust a syntax error occurring inside the function body of a CREATE
   * FUNCTION or DO command.  This can be used by any function validator or
   * anonymous-block handler, 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 command text; 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 or DO 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 original 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;
  }
  