Пример #1
0
/*
 *	Parse a function call
 *
 *	For historical reasons, Postgres tries to treat the notations tab.col
 *	and col(tab) as equivalent: if a single-argument function call has an
 *	argument of complex type and the (unqualified) function name matches
 *	any attribute of the type, we take it as a column projection.  Conversely
 *	a function of a single complex-type argument can be written like a
 *	column reference, allowing functions to act like computed columns.
 *
 *	Hence, both cases come through here.  The is_column parameter tells us
 *	which syntactic construct is actually being dealt with, but this is
 *	intended to be used only to deliver an appropriate error message,
 *	not to affect the semantics.  When is_column is true, we should have
 *	a single argument (the putative table), unqualified function name
 *	equal to the column name, and no aggregate or variadic decoration.
 *
 *	The argument expressions (in fargs) must have been transformed already.
 */
Node *
ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
				  bool agg_star, bool agg_distinct, bool func_variadic,
				  WindowDef *over, bool is_column, int location)
{
	Oid			rettype;
	Oid			funcid;
	ListCell   *l;
	ListCell   *nextl;
	Node	   *first_arg = NULL;
	int			nargs;
	int			nargsplusdefs;
	Oid			actual_arg_types[FUNC_MAX_ARGS];
	Oid		   *declared_arg_types;
	List	   *argdefaults;
	Node	   *retval;
	bool		retset;
	int			nvargs;
	FuncDetailCode fdresult;

	/*
	 * Most of the rest of the parser just assumes that functions do not have
	 * more than FUNC_MAX_ARGS parameters.	We have to test here to protect
	 * against array overruns, etc.  Of course, this may not be a function,
	 * but the test doesn't hurt.
	 */
	if (list_length(fargs) > FUNC_MAX_ARGS)
		ereport(ERROR,
				(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
			 errmsg_plural("cannot pass more than %d argument to a function",
						   "cannot pass more than %d arguments to a function",
						   FUNC_MAX_ARGS,
						   FUNC_MAX_ARGS),
				 parser_errposition(pstate, location)));

	/*
	 * Extract arg type info in preparation for function lookup.
	 *
	 * If any arguments are Param markers of type VOID, we discard them from
	 * the parameter list.	This is a hack to allow the JDBC driver to not
	 * have to distinguish "input" and "output" parameter symbols while
	 * parsing function-call constructs.  We can't use foreach() because we
	 * may modify the list ...
	 */
	nargs = 0;
	for (l = list_head(fargs); l != NULL; l = nextl)
	{
		Node	   *arg = lfirst(l);
		Oid			argtype = exprType(arg);

		nextl = lnext(l);

		if (argtype == VOIDOID && IsA(arg, Param) &&!is_column)
		{
			fargs = list_delete_ptr(fargs, arg);
			continue;
		}

		actual_arg_types[nargs++] = argtype;
	}

	if (fargs)
	{
		first_arg = linitial(fargs);
		Assert(first_arg != NULL);
	}

	/*
	 * Check for column projection: if function has one argument, and that
	 * argument is of complex type, and function name is not qualified, then
	 * the "function call" could be a projection.  We also check that there
	 * wasn't any aggregate or variadic decoration.
	 */
	if (nargs == 1 && !agg_star && !agg_distinct && over == NULL &&
		!func_variadic && list_length(funcname) == 1)
	{
		Oid			argtype = actual_arg_types[0];

		if (argtype == RECORDOID || ISCOMPLEX(argtype))
		{
			retval = ParseComplexProjection(pstate,
											strVal(linitial(funcname)),
											first_arg,
											location);
			if (retval)
				return retval;

			/*
			 * If ParseComplexProjection doesn't recognize it as a projection,
			 * just press on.
			 */
		}
	}

	/*
	 * Okay, it's not a column projection, so it must really be a function.
	 * func_get_detail looks up the function in the catalogs, does
	 * disambiguation for polymorphic functions, handles inheritance, and
	 * returns the funcid and type and set or singleton status of the
	 * function's return value.  It also returns the true argument types to
	 * the function.  In the case of a variadic function call, the reported
	 * "true" types aren't really what is in pg_proc: the variadic argument is
	 * replaced by a suitable number of copies of its element type.  We'll fix
	 * it up below.  We may also have to deal with default arguments.
	 */
	fdresult = func_get_detail(funcname, fargs, nargs, actual_arg_types,
							   !func_variadic, true,
							   &funcid, &rettype, &retset, &nvargs,
							   &declared_arg_types, &argdefaults);
	if (fdresult == FUNCDETAIL_COERCION)
	{
		/*
		 * We interpreted it as a type coercion. coerce_type can handle these
		 * cases, so why duplicate code...
		 */
		return coerce_type(pstate, linitial(fargs),
						   actual_arg_types[0], rettype, -1,
						   COERCION_EXPLICIT, COERCE_EXPLICIT_CALL, location);
	}
	else if (fdresult == FUNCDETAIL_NORMAL)
	{
		/*
		 * Normal function found; was there anything indicating it must be an
		 * aggregate?
		 */
		if (agg_star)
			ereport(ERROR,
					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
			   errmsg("%s(*) specified, but %s is not an aggregate function",
					  NameListToString(funcname),
					  NameListToString(funcname)),
					 parser_errposition(pstate, location)));
		if (agg_distinct)
			ereport(ERROR,
					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
			errmsg("DISTINCT specified, but %s is not an aggregate function",
				   NameListToString(funcname)),
					 parser_errposition(pstate, location)));
		if (over)
			ereport(ERROR,
					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
					 errmsg("OVER specified, but %s is not a window function nor an aggregate function",
							NameListToString(funcname)),
					 parser_errposition(pstate, location)));
	}
	else if (!(fdresult == FUNCDETAIL_AGGREGATE ||
			   fdresult == FUNCDETAIL_WINDOWFUNC))
	{
		/*
		 * Oops.  Time to die.
		 *
		 * If we are dealing with the attribute notation rel.function, give an
		 * error message that is appropriate for that case.
		 */
		if (is_column)
		{
			Assert(nargs == 1);
			Assert(list_length(funcname) == 1);
			unknown_attribute(pstate, first_arg, strVal(linitial(funcname)),
							  location);
		}

		/*
		 * Else generate a detailed complaint for a function
		 */
		if (fdresult == FUNCDETAIL_MULTIPLE)
			ereport(ERROR,
					(errcode(ERRCODE_AMBIGUOUS_FUNCTION),
					 errmsg("function %s is not unique",
							func_signature_string(funcname, nargs,
												  actual_arg_types)),
					 errhint("Could not choose a best candidate function. "
							 "You might need to add explicit type casts."),
					 parser_errposition(pstate, location)));
		else
			ereport(ERROR,
					(errcode(ERRCODE_UNDEFINED_FUNCTION),
					 errmsg("function %s does not exist",
							func_signature_string(funcname, nargs,
												  actual_arg_types)),
			errhint("No function matches the given name and argument types. "
					"You might need to add explicit type casts."),
					 parser_errposition(pstate, location)));
	}

	/*
	 * If there are default arguments, we have to include their types in
	 * actual_arg_types for the purpose of checking generic type consistency.
	 * However, we do NOT put them into the generated parse node, because
	 * their actual values might change before the query gets run.	The
	 * planner has to insert the up-to-date values at plan time.
	 */
	nargsplusdefs = nargs;
	foreach(l, argdefaults)
	{
		Node	   *expr = (Node *) lfirst(l);

		/* probably shouldn't happen ... */
		if (nargsplusdefs >= FUNC_MAX_ARGS)
			ereport(ERROR,
					(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
			 errmsg_plural("cannot pass more than %d argument to a function",
						   "cannot pass more than %d arguments to a function",
						   FUNC_MAX_ARGS,
						   FUNC_MAX_ARGS),
					 parser_errposition(pstate, location)));

		actual_arg_types[nargsplusdefs++] = exprType(expr);
	}
Пример #2
0
/*
 *	Parse a function call
 *
 *	For historical reasons, Postgres tries to treat the notations tab.col
 *	and col(tab) as equivalent: if a single-argument function call has an
 *	argument of complex type and the (unqualified) function name matches
 *	any attribute of the type, we take it as a column projection.  Conversely
 *	a function of a single complex-type argument can be written like a
 *	column reference, allowing functions to act like computed columns.
 *
 *	Hence, both cases come through here.  The is_column parameter tells us
 *	which syntactic construct is actually being dealt with, but this is
 *	intended to be used only to deliver an appropriate error message,
 *	not to affect the semantics.  When is_column is true, we should have
 *	a single argument (the putative table), unqualified function name
 *	equal to the column name, and no aggregate decoration.
 *
 *	The argument expressions (in fargs) must have been transformed already.
 */
Node *
ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
				  bool agg_star, bool agg_distinct, bool is_column)
{
	Oid			rettype;
	Oid			funcid;
	ListCell   *l;
	Node	   *first_arg = NULL;
	int			nargs = list_length(fargs);
	int			argn;
	Oid			actual_arg_types[FUNC_MAX_ARGS];
	Oid		   *declared_arg_types;
	Node	   *retval;
	bool		retset;
	FuncDetailCode fdresult;

	/*
	 * Most of the rest of the parser just assumes that functions do not
	 * have more than FUNC_MAX_ARGS parameters.  We have to test here to
	 * protect against array overruns, etc.  Of course, this may not be a
	 * function, but the test doesn't hurt.
	 */
	if (nargs > FUNC_MAX_ARGS)
		ereport(ERROR,
				(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
			   errmsg("cannot pass more than %d arguments to a function",
					  FUNC_MAX_ARGS)));

	if (fargs)
	{
		first_arg = linitial(fargs);
		Assert(first_arg != NULL);
	}

	/*
	 * Check for column projection: if function has one argument, and that
	 * argument is of complex type, and function name is not qualified,
	 * then the "function call" could be a projection.	We also check that
	 * there wasn't any aggregate decoration.
	 */
	if (nargs == 1 && !agg_star && !agg_distinct && list_length(funcname) == 1)
	{
		Oid			argtype = exprType(first_arg);

		if (argtype == RECORDOID || ISCOMPLEX(argtype))
		{
			retval = ParseComplexProjection(pstate,
											strVal(linitial(funcname)),
											first_arg);
			if (retval)
				return retval;

			/*
			 * If ParseComplexProjection doesn't recognize it as a
			 * projection, just press on.
			 */
		}
	}

	/*
	 * Okay, it's not a column projection, so it must really be a
	 * function. Extract arg type info in preparation for function lookup.
	 */
	MemSet(actual_arg_types, 0, FUNC_MAX_ARGS * sizeof(Oid));

	argn = 0;
	foreach(l, fargs)
	{
		Node	   *arg = lfirst(l);

		actual_arg_types[argn++] = exprType(arg);
	}