funcapi.c

来自「postgresql8.3.4源码,开源数据库」· C语言 代码 · 共 1,163 行 · 第 1/3 页

			break;
		default:
			break;
	}

	ReleaseSysCache(tp);

	return result;
}

/*
 * Given the result tuple descriptor for a function with OUT parameters,
 * replace any polymorphic columns (ANYELEMENT etc) with correct data types
 * deduced from the input arguments. Returns TRUE if able to deduce all types,
 * FALSE if not.
 */
static bool
resolve_polymorphic_tupdesc(TupleDesc tupdesc, oidvector *declared_args,
							Node *call_expr)
{
	int			natts = tupdesc->natts;
	int			nargs = declared_args->dim1;
	bool		have_anyelement_result = false;
	bool		have_anyarray_result = false;
	bool		have_anynonarray = false;
	bool		have_anyenum = false;
	Oid			anyelement_type = InvalidOid;
	Oid			anyarray_type = InvalidOid;
	int			i;

	/* See if there are any polymorphic outputs; quick out if not */
	for (i = 0; i < natts; i++)
	{
		switch (tupdesc->attrs[i]->atttypid)
		{
			case ANYELEMENTOID:
				have_anyelement_result = true;
				break;
			case ANYARRAYOID:
				have_anyarray_result = true;
				break;
			case ANYNONARRAYOID:
				have_anyelement_result = true;
				have_anynonarray = true;
				break;
			case ANYENUMOID:
				have_anyelement_result = true;
				have_anyenum = true;
				break;
			default:
				break;
		}
	}
	if (!have_anyelement_result && !have_anyarray_result)
		return true;

	/*
	 * Otherwise, extract actual datatype(s) from input arguments.	(We assume
	 * the parser already validated consistency of the arguments.)
	 */
	if (!call_expr)
		return false;			/* no hope */

	for (i = 0; i < nargs; i++)
	{
		switch (declared_args->values[i])
		{
			case ANYELEMENTOID:
			case ANYNONARRAYOID:
			case ANYENUMOID:
				if (!OidIsValid(anyelement_type))
					anyelement_type = get_call_expr_argtype(call_expr, i);
				break;
			case ANYARRAYOID:
				if (!OidIsValid(anyarray_type))
					anyarray_type = get_call_expr_argtype(call_expr, i);
				break;
			default:
				break;
		}
	}

	/* If nothing found, parser messed up */
	if (!OidIsValid(anyelement_type) && !OidIsValid(anyarray_type))
		return false;

	/* If needed, deduce one polymorphic type from the other */
	if (have_anyelement_result && !OidIsValid(anyelement_type))
		anyelement_type = resolve_generic_type(ANYELEMENTOID,
											   anyarray_type,
											   ANYARRAYOID);
	if (have_anyarray_result && !OidIsValid(anyarray_type))
		anyarray_type = resolve_generic_type(ANYARRAYOID,
											 anyelement_type,
											 ANYELEMENTOID);

	/* Enforce ANYNONARRAY if needed */
	if (have_anynonarray && type_is_array(anyelement_type))
		return false;

	/* Enforce ANYENUM if needed */
	if (have_anyenum && !type_is_enum(anyelement_type))
		return false;

	/* And finally replace the tuple column types as needed */
	for (i = 0; i < natts; i++)
	{
		switch (tupdesc->attrs[i]->atttypid)
		{
			case ANYELEMENTOID:
			case ANYNONARRAYOID:
			case ANYENUMOID:
				TupleDescInitEntry(tupdesc, i + 1,
								   NameStr(tupdesc->attrs[i]->attname),
								   anyelement_type,
								   -1,
								   0);
				break;
			case ANYARRAYOID:
				TupleDescInitEntry(tupdesc, i + 1,
								   NameStr(tupdesc->attrs[i]->attname),
								   anyarray_type,
								   -1,
								   0);
				break;
			default:
				break;
		}
	}

	return true;
}

/*
 * Given the declared argument types and modes for a function, replace any
 * polymorphic types (ANYELEMENT etc) with correct data types deduced from the
 * input arguments.  Returns TRUE if able to deduce all types, FALSE if not.
 * This is the same logic as resolve_polymorphic_tupdesc, but with a different
 * argument representation.
 *
 * argmodes may be NULL, in which case all arguments are assumed to be IN mode.
 */
bool
resolve_polymorphic_argtypes(int numargs, Oid *argtypes, char *argmodes,
							 Node *call_expr)
{
	bool		have_anyelement_result = false;
	bool		have_anyarray_result = false;
	Oid			anyelement_type = InvalidOid;
	Oid			anyarray_type = InvalidOid;
	int			inargno;
	int			i;

	/* First pass: resolve polymorphic inputs, check for outputs */
	inargno = 0;
	for (i = 0; i < numargs; i++)
	{
		char		argmode = argmodes ? argmodes[i] : PROARGMODE_IN;

		switch (argtypes[i])
		{
			case ANYELEMENTOID:
			case ANYNONARRAYOID:
			case ANYENUMOID:
				if (argmode == PROARGMODE_OUT)
					have_anyelement_result = true;
				else
				{
					if (!OidIsValid(anyelement_type))
					{
						anyelement_type = get_call_expr_argtype(call_expr,
																inargno);
						if (!OidIsValid(anyelement_type))
							return false;
					}
					argtypes[i] = anyelement_type;
				}
				break;
			case ANYARRAYOID:
				if (argmode == PROARGMODE_OUT)
					have_anyarray_result = true;
				else
				{
					if (!OidIsValid(anyarray_type))
					{
						anyarray_type = get_call_expr_argtype(call_expr,
															  inargno);
						if (!OidIsValid(anyarray_type))
							return false;
					}
					argtypes[i] = anyarray_type;
				}
				break;
			default:
				break;
		}
		if (argmode != PROARGMODE_OUT)
			inargno++;
	}

	/* Done? */
	if (!have_anyelement_result && !have_anyarray_result)
		return true;

	/* If no input polymorphics, parser messed up */
	if (!OidIsValid(anyelement_type) && !OidIsValid(anyarray_type))
		return false;

	/* If needed, deduce one polymorphic type from the other */
	if (have_anyelement_result && !OidIsValid(anyelement_type))
		anyelement_type = resolve_generic_type(ANYELEMENTOID,
											   anyarray_type,
											   ANYARRAYOID);
	if (have_anyarray_result && !OidIsValid(anyarray_type))
		anyarray_type = resolve_generic_type(ANYARRAYOID,
											 anyelement_type,
											 ANYELEMENTOID);

	/* XXX do we need to enforce ANYNONARRAY or ANYENUM here?  I think not */

	/* And finally replace the output column types as needed */
	for (i = 0; i < numargs; i++)
	{
		switch (argtypes[i])
		{
			case ANYELEMENTOID:
			case ANYNONARRAYOID:
			case ANYENUMOID:
				argtypes[i] = anyelement_type;
				break;
			case ANYARRAYOID:
				argtypes[i] = anyarray_type;
				break;
			default:
				break;
		}
	}

	return true;
}

/*
 * get_type_func_class
 *		Given the type OID, obtain its TYPEFUNC classification.
 *
 * This is intended to centralize a bunch of formerly ad-hoc code for
 * classifying types.  The categories used here are useful for deciding
 * how to handle functions returning the datatype.
 */
static TypeFuncClass
get_type_func_class(Oid typid)
{
	switch (get_typtype(typid))
	{
		case TYPTYPE_COMPOSITE:
			return TYPEFUNC_COMPOSITE;
		case TYPTYPE_BASE:
		case TYPTYPE_DOMAIN:
		case TYPTYPE_ENUM:
			return TYPEFUNC_SCALAR;
		case TYPTYPE_PSEUDO:
			if (typid == RECORDOID)
				return TYPEFUNC_RECORD;

			/*
			 * We treat VOID and CSTRING as legitimate scalar datatypes,
			 * mostly for the convenience of the JDBC driver (which wants to
			 * be able to do "SELECT * FROM foo()" for all legitimately
			 * user-callable functions).
			 */
			if (typid == VOIDOID || typid == CSTRINGOID)
				return TYPEFUNC_SCALAR;
			return TYPEFUNC_OTHER;
	}
	/* shouldn't get here, probably */
	return TYPEFUNC_OTHER;
}


/*
 * get_func_arg_info
 *
 * Fetch info about the argument types, names, and IN/OUT modes from the
 * pg_proc tuple.  Return value is the total number of arguments.
 * Other results are palloc'd.  *p_argtypes is always filled in, but
 * *p_argnames and *p_argmodes will be set NULL in the default cases
 * (no names, and all IN arguments, respectively).
 *
 * Note that this function simply fetches what is in the pg_proc tuple;
 * it doesn't do any interpretation of polymorphic types.
 */
int
get_func_arg_info(HeapTuple procTup,
				  Oid **p_argtypes, char ***p_argnames, char **p_argmodes)
{
	Form_pg_proc procStruct = (Form_pg_proc) GETSTRUCT(procTup);
	Datum		proallargtypes;
	Datum		proargmodes;
	Datum		proargnames;
	bool		isNull;
	ArrayType  *arr;
	int			numargs;
	Datum	   *elems;
	int			nelems;
	int			i;

	/* First discover the total number of parameters and get their types */
	proallargtypes = SysCacheGetAttr(PROCOID, procTup,
									 Anum_pg_proc_proallargtypes,
									 &isNull);
	if (!isNull)
	{
		/*
		 * We expect the arrays to be 1-D arrays of the right types; verify
		 * that.  For the OID and char arrays, we don't need to use
		 * deconstruct_array() since the array data is just going to look like
		 * a C array of values.
		 */
		arr = DatumGetArrayTypeP(proallargtypes);		/* ensure not toasted */
		numargs = ARR_DIMS(arr)[0];
		if (ARR_NDIM(arr) != 1 ||
			numargs < 0 ||
			ARR_HASNULL(arr) ||
			ARR_ELEMTYPE(arr) != OIDOID)
			elog(ERROR, "proallargtypes is not a 1-D Oid array");
		Assert(numargs >= procStruct->pronargs);
		*p_argtypes = (Oid *) palloc(numargs * sizeof(Oid));
		memcpy(*p_argtypes, ARR_DATA_PTR(arr),
			   numargs * sizeof(Oid));
	}
	else
	{
		/* If no proallargtypes, use proargtypes */
		numargs = procStruct->proargtypes.dim1;
		Assert(numargs == procStruct->pronargs);
		*p_argtypes = (Oid *) palloc(numargs * sizeof(Oid));
		memcpy(*p_argtypes, procStruct->proargtypes.values,
			   numargs * sizeof(Oid));
	}

	/* Get argument names, if available */
	proargnames = SysCacheGetAttr(PROCOID, procTup,
								  Anum_pg_proc_proargnames,
								  &isNull);
	if (isNull)
		*p_argnames = NULL;
	else
	{
		deconstruct_array(DatumGetArrayTypeP(proargnames),
						  TEXTOID, -1, false, 'i',
						  &elems, NULL, &nelems);
		if (nelems != numargs)	/* should not happen */
			elog(ERROR, "proargnames must have the same number of elements as the function has arguments");
		*p_argnames = (char **) palloc(sizeof(char *) * numargs);
		for (i = 0; i < numargs; i++)
			(*p_argnames)[i] = DatumGetCString(DirectFunctionCall1(textout,
																   elems[i]));
	}

	/* Get argument modes, if available */
	proargmodes = SysCacheGetAttr(PROCOID, procTup,
								  Anum_pg_proc_proargmodes,
								  &isNull);
	if (isNull)
		*p_argmodes = NULL;
	else
	{
		arr = DatumGetArrayTypeP(proargmodes);	/* ensure not toasted */
		if (ARR_NDIM(arr) != 1 ||
			ARR_DIMS(arr)[0] != numargs ||
			ARR_HASNULL(arr) ||
			ARR_ELEMTYPE(arr) != CHAROID)
			elog(ERROR, "proargmodes is not a 1-D char array");
		*p_argmodes = (char *) palloc(numargs * sizeof(char));
		memcpy(*p_argmodes, ARR_DATA_PTR(arr),
			   numargs * sizeof(char));
	}

	return numargs;
}


/*
 * get_func_result_name
 *
 * If the function has exactly one output parameter, and that parameter
 * is named, return the name (as a palloc'd string).  Else return NULL.
 *