fmgr.c

来自「postgresql8.3.4源码,开源数据库」· C语言 代码 · 共 2,224 行 · 第 1/4 页

	fcinfo.arg[0] = arg1;
	fcinfo.arg[1] = arg2;
	fcinfo.arg[2] = arg3;
	fcinfo.arg[3] = arg4;
	fcinfo.arg[4] = arg5;
	fcinfo.arg[5] = arg6;
	fcinfo.argnull[0] = false;
	fcinfo.argnull[1] = false;
	fcinfo.argnull[2] = false;
	fcinfo.argnull[3] = false;
	fcinfo.argnull[4] = false;
	fcinfo.argnull[5] = false;

	result = FunctionCallInvoke(&fcinfo);

	/* Check for null result, since caller is clearly not expecting one */
	if (fcinfo.isnull)
		elog(ERROR, "function %u returned NULL", flinfo.fn_oid);

	return result;
}

Datum
OidFunctionCall7(Oid functionId, Datum arg1, Datum arg2,
				 Datum arg3, Datum arg4, Datum arg5,
				 Datum arg6, Datum arg7)
{
	FmgrInfo	flinfo;
	FunctionCallInfoData fcinfo;
	Datum		result;

	fmgr_info(functionId, &flinfo);

	InitFunctionCallInfoData(fcinfo, &flinfo, 7, NULL, NULL);

	fcinfo.arg[0] = arg1;
	fcinfo.arg[1] = arg2;
	fcinfo.arg[2] = arg3;
	fcinfo.arg[3] = arg4;
	fcinfo.arg[4] = arg5;
	fcinfo.arg[5] = arg6;
	fcinfo.arg[6] = arg7;
	fcinfo.argnull[0] = false;
	fcinfo.argnull[1] = false;
	fcinfo.argnull[2] = false;
	fcinfo.argnull[3] = false;
	fcinfo.argnull[4] = false;
	fcinfo.argnull[5] = false;
	fcinfo.argnull[6] = false;

	result = FunctionCallInvoke(&fcinfo);

	/* Check for null result, since caller is clearly not expecting one */
	if (fcinfo.isnull)
		elog(ERROR, "function %u returned NULL", flinfo.fn_oid);

	return result;
}

Datum
OidFunctionCall8(Oid functionId, Datum arg1, Datum arg2,
				 Datum arg3, Datum arg4, Datum arg5,
				 Datum arg6, Datum arg7, Datum arg8)
{
	FmgrInfo	flinfo;
	FunctionCallInfoData fcinfo;
	Datum		result;

	fmgr_info(functionId, &flinfo);

	InitFunctionCallInfoData(fcinfo, &flinfo, 8, NULL, NULL);

	fcinfo.arg[0] = arg1;
	fcinfo.arg[1] = arg2;
	fcinfo.arg[2] = arg3;
	fcinfo.arg[3] = arg4;
	fcinfo.arg[4] = arg5;
	fcinfo.arg[5] = arg6;
	fcinfo.arg[6] = arg7;
	fcinfo.arg[7] = arg8;
	fcinfo.argnull[0] = false;
	fcinfo.argnull[1] = false;
	fcinfo.argnull[2] = false;
	fcinfo.argnull[3] = false;
	fcinfo.argnull[4] = false;
	fcinfo.argnull[5] = false;
	fcinfo.argnull[6] = false;
	fcinfo.argnull[7] = false;

	result = FunctionCallInvoke(&fcinfo);

	/* Check for null result, since caller is clearly not expecting one */
	if (fcinfo.isnull)
		elog(ERROR, "function %u returned NULL", flinfo.fn_oid);

	return result;
}

Datum
OidFunctionCall9(Oid functionId, Datum arg1, Datum arg2,
				 Datum arg3, Datum arg4, Datum arg5,
				 Datum arg6, Datum arg7, Datum arg8,
				 Datum arg9)
{
	FmgrInfo	flinfo;
	FunctionCallInfoData fcinfo;
	Datum		result;

	fmgr_info(functionId, &flinfo);

	InitFunctionCallInfoData(fcinfo, &flinfo, 9, NULL, NULL);

	fcinfo.arg[0] = arg1;
	fcinfo.arg[1] = arg2;
	fcinfo.arg[2] = arg3;
	fcinfo.arg[3] = arg4;
	fcinfo.arg[4] = arg5;
	fcinfo.arg[5] = arg6;
	fcinfo.arg[6] = arg7;
	fcinfo.arg[7] = arg8;
	fcinfo.arg[8] = arg9;
	fcinfo.argnull[0] = false;
	fcinfo.argnull[1] = false;
	fcinfo.argnull[2] = false;
	fcinfo.argnull[3] = false;
	fcinfo.argnull[4] = false;
	fcinfo.argnull[5] = false;
	fcinfo.argnull[6] = false;
	fcinfo.argnull[7] = false;
	fcinfo.argnull[8] = false;

	result = FunctionCallInvoke(&fcinfo);

	/* Check for null result, since caller is clearly not expecting one */
	if (fcinfo.isnull)
		elog(ERROR, "function %u returned NULL", flinfo.fn_oid);

	return result;
}


/*
 * Special cases for convenient invocation of datatype I/O functions.
 */

/*
 * Call a previously-looked-up datatype input function.
 *
 * "str" may be NULL to indicate we are reading a NULL.  In this case
 * the caller should assume the result is NULL, but we'll call the input
 * function anyway if it's not strict.  So this is almost but not quite
 * the same as FunctionCall3.
 */
Datum
InputFunctionCall(FmgrInfo *flinfo, char *str, Oid typioparam, int32 typmod)
{
	FunctionCallInfoData fcinfo;
	Datum		result;

	if (str == NULL && flinfo->fn_strict)
		return (Datum) 0;		/* just return null result */

	InitFunctionCallInfoData(fcinfo, flinfo, 3, NULL, NULL);

	fcinfo.arg[0] = CStringGetDatum(str);
	fcinfo.arg[1] = ObjectIdGetDatum(typioparam);
	fcinfo.arg[2] = Int32GetDatum(typmod);
	fcinfo.argnull[0] = (str == NULL);
	fcinfo.argnull[1] = false;
	fcinfo.argnull[2] = false;

	result = FunctionCallInvoke(&fcinfo);

	/* Should get null result if and only if str is NULL */
	if (str == NULL)
	{
		if (!fcinfo.isnull)
			elog(ERROR, "input function %u returned non-NULL",
				 fcinfo.flinfo->fn_oid);
	}
	else
	{
		if (fcinfo.isnull)
			elog(ERROR, "input function %u returned NULL",
				 fcinfo.flinfo->fn_oid);
	}

	return result;
}

/*
 * Call a previously-looked-up datatype output function.
 *
 * Do not call this on NULL datums.
 *
 * This is mere window dressing for FunctionCall1, but its use is recommended
 * anyway so that code invoking output functions can be identified easily.
 */
char *
OutputFunctionCall(FmgrInfo *flinfo, Datum val)
{
	return DatumGetCString(FunctionCall1(flinfo, val));
}

/*
 * Call a previously-looked-up datatype binary-input function.
 *
 * "buf" may be NULL to indicate we are reading a NULL.  In this case
 * the caller should assume the result is NULL, but we'll call the receive
 * function anyway if it's not strict.  So this is almost but not quite
 * the same as FunctionCall3.
 */
Datum
ReceiveFunctionCall(FmgrInfo *flinfo, StringInfo buf,
					Oid typioparam, int32 typmod)
{
	FunctionCallInfoData fcinfo;
	Datum		result;

	if (buf == NULL && flinfo->fn_strict)
		return (Datum) 0;		/* just return null result */

	InitFunctionCallInfoData(fcinfo, flinfo, 3, NULL, NULL);

	fcinfo.arg[0] = PointerGetDatum(buf);
	fcinfo.arg[1] = ObjectIdGetDatum(typioparam);
	fcinfo.arg[2] = Int32GetDatum(typmod);
	fcinfo.argnull[0] = (buf == NULL);
	fcinfo.argnull[1] = false;
	fcinfo.argnull[2] = false;

	result = FunctionCallInvoke(&fcinfo);

	/* Should get null result if and only if buf is NULL */
	if (buf == NULL)
	{
		if (!fcinfo.isnull)
			elog(ERROR, "receive function %u returned non-NULL",
				 fcinfo.flinfo->fn_oid);
	}
	else
	{
		if (fcinfo.isnull)
			elog(ERROR, "receive function %u returned NULL",
				 fcinfo.flinfo->fn_oid);
	}

	return result;
}

/*
 * Call a previously-looked-up datatype binary-output function.
 *
 * Do not call this on NULL datums.
 *
 * This is little more than window dressing for FunctionCall1, but its use is
 * recommended anyway so that code invoking output functions can be identified
 * easily.	Note however that it does guarantee a non-toasted result.
 */
bytea *
SendFunctionCall(FmgrInfo *flinfo, Datum val)
{
	return DatumGetByteaP(FunctionCall1(flinfo, val));
}

/*
 * As above, for I/O functions identified by OID.  These are only to be used
 * in seldom-executed code paths.  They are not only slow but leak memory.
 */
Datum
OidInputFunctionCall(Oid functionId, char *str, Oid typioparam, int32 typmod)
{
	FmgrInfo	flinfo;

	fmgr_info(functionId, &flinfo);
	return InputFunctionCall(&flinfo, str, typioparam, typmod);
}

char *
OidOutputFunctionCall(Oid functionId, Datum val)
{
	FmgrInfo	flinfo;

	fmgr_info(functionId, &flinfo);
	return OutputFunctionCall(&flinfo, val);
}

Datum
OidReceiveFunctionCall(Oid functionId, StringInfo buf,
					   Oid typioparam, int32 typmod)
{
	FmgrInfo	flinfo;

	fmgr_info(functionId, &flinfo);
	return ReceiveFunctionCall(&flinfo, buf, typioparam, typmod);
}

bytea *
OidSendFunctionCall(Oid functionId, Datum val)
{
	FmgrInfo	flinfo;

	fmgr_info(functionId, &flinfo);
	return SendFunctionCall(&flinfo, val);
}


/*
 * !!! OLD INTERFACE !!!
 *
 * fmgr() is the only remaining vestige of the old-style caller support
 * functions.  It's no longer used anywhere in the Postgres distribution,
 * but we should leave it around for a release or two to ease the transition
 * for user-supplied C functions.  OidFunctionCallN() replaces it for new
 * code.
 *
 * DEPRECATED, DO NOT USE IN NEW CODE
 */
char *
fmgr(Oid procedureId,...)
{
	FmgrInfo	flinfo;
	FunctionCallInfoData fcinfo;
	int			n_arguments;
	Datum		result;

	fmgr_info(procedureId, &flinfo);

	MemSet(&fcinfo, 0, sizeof(fcinfo));
	fcinfo.flinfo = &flinfo;
	fcinfo.nargs = flinfo.fn_nargs;
	n_arguments = fcinfo.nargs;

	if (n_arguments > 0)
	{
		va_list		pvar;
		int			i;

		if (n_arguments > FUNC_MAX_ARGS)
			ereport(ERROR,
					(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
			 errmsg("function %u has too many arguments (%d, maximum is %d)",
					flinfo.fn_oid, n_arguments, FUNC_MAX_ARGS)));
		va_start(pvar, procedureId);
		for (i = 0; i < n_arguments; i++)
			fcinfo.arg[i] = (Datum) va_arg(pvar, char *);
		va_end(pvar);
	}

	result = FunctionCallInvoke(&fcinfo);

	/* Check for null result, since caller is clearly not expecting one */
	if (fcinfo.isnull)
		elog(ERROR, "function %u returned NULL", flinfo.fn_oid);

	return (char *) result;
}


/*-------------------------------------------------------------------------
 *		Support routines for standard pass-by-reference datatypes
 *
 * Note: at some point, at least on some platforms, these might become
 * pass-by-value types.  Obviously Datum must be >= 8 bytes to allow
 * int64 or float8 to be pass-by-value.  I think that Float4GetDatum
 * and Float8GetDatum will need to be out-of-line routines anyway,
 * since just casting from float to Datum will not do the right thing;
 * some kind of trick with pointer-casting or a union will be needed.
 *-------------------------------------------------------------------------
 */

Datum
Int64GetDatum(int64 X)
{
#ifndef INT64_IS_BUSTED
	int64	   *retval = (int64 *) palloc(sizeof(int64));

	*retval = X;
	return PointerGetDatum(retval);
#else							/* INT64_IS_BUSTED */

	/*
	 * On a machine with no 64-bit-int C datatype, sizeof(int64) will not be
	 * 8, but we want Int64GetDatum to return an 8-byte object anyway, with
	 * zeroes in the unused bits.  This is needed so that, for example, hash
	 * join of int8 will behave properly.
	 */
	int64	   *retval = (int64 *) palloc0(Max(sizeof(int64), 8));

	*retval = X;
	return PointerGetDatum(retval);
#endif   /* INT64_IS_BUSTED */
}

Datum
Float4GetDatum(float4 X)
{
	float4	   *retval = (float4 *) palloc(sizeof(float4));

	*retval = X;
	return PointerGetDatum(retval);
}

Datum
Float8GetDatum(float8 X)
{
	float8	   *retval = (float8 *) palloc(sizeof(float8));

	*retval = X;
	return PointerGetDatum(retval);
}

/*-------------------------------------------------------------------------
 *		Support routines for toastable datatypes
 *-------------------------------------------------------------------------
 */

struct varlena *
pg_detoast_datum(struct varlena * datum)
{
	if (VARATT_IS_EXTENDED(datum))
		return heap_tuple_untoast_attr(datum);
	else
		return datum;
}

struct varlena *
pg_detoast_datum_copy(struct varlena * datum)
{
	if (VARATT_IS_EXTENDED(datum))
		return heap_tuple_untoast_attr(datum);
	else
	{
		/* Make a modifiable copy of the varlena object */
		Size		len = VARSIZE(datum);
		struct varlena *result = (struct varlena *) palloc(len);

		memcpy(result, datum, len);
		return result;
	}
}

struct varlena *
pg_detoast_datum_slice(struct varlena * datum, int32 first, int32 count)
{
	/* Only get the specified portion from the toast rel */
	return heap_tuple_untoast_attr_slice(datum, first, count);
}

struct varlena *
pg_detoast_datum_packed(struct varlena * datum)
{
	if (VARATT_IS_COMPRESSED(datum) || VARATT_IS_EXTERNAL(datum))
		return heap_tuple_untoast_attr(datum);
	else
		return datum;
}

/*-------------------------------------------------------------------------
 *		Support routines for extracting info from fn_expr parse tree
 *
 * These are needed by polymorphic functions, which accept multiple possible
 * input types and need help from the parser to know what they've got.
 *-------------------------------------------------------------------------
 */

/*
 * Get the actual type OID of the function return type
 *
 * Returns InvalidOid if information is not available
 */
Oid
get_fn_expr_rettype(FmgrInfo *flinfo)
{
	Node	   *expr;

	/*
	 * can't return anything useful if we have no FmgrInfo or if its fn_expr
	 * node has not been initialized
	 */
	if (!flinfo || !flinfo->fn_expr)
		return InvalidOid;

	expr = flinfo->fn_expr;

	return exprType(expr);
}

/*
 * Get the actual type OID of a specific function argument (counting from 0)
 *
 * Returns InvalidOid if information is not available
 */
Oid
get_fn_expr_argtype(FmgrInfo *flinfo, int argnum)
{
	/*
	 * can't return anything useful if we have no FmgrInfo or if its fn_expr
	 * node has not been initialized
	 */
	if (!flinfo || !flinfo->fn_expr)
		return InvalidOid;

	return get_call_expr_argtype(flinfo->fn_expr, argnum);
}

/*
 * Get the actual type OID of a specific function argument (counting from 0),
 * but working from the calling expression tree instead of FmgrInfo
 *
 * Returns InvalidOid if information is not available
 */
Oid
get_call_expr_argtype(Node *expr, int argnum)
{
	List	   *args;
	Oid			argtype;

	if (expr == NULL)
		return InvalidOid;

	if (IsA(expr, FuncExpr))
		args = ((FuncExpr *) expr)->args;
	else if (IsA(expr, OpExpr))
		args = ((OpExpr *) expr)->args;
	else if (IsA(expr, DistinctExpr))
		args = ((DistinctExpr *) expr)->args;
	else if (IsA(expr, ScalarArrayOpExpr))
		args = ((ScalarArrayOpExpr *) expr)->args;
	else if (IsA(expr, ArrayCoerceExpr))
		args = list_make1(((ArrayCoerceExpr *) expr)->arg);
	else if (IsA(expr, NullIfExpr))
		args = ((NullIfExpr *) expr)->args;
	else
		return InvalidOid;

	if (argnum < 0 || argnum >= list_length(args))
		return InvalidOid;

	argtype = exprType((Node *) list_nth(args, argnum));

	/*
	 * special hack for ScalarArrayOpExpr and ArrayCoerceExpr: what the
	 * underlying function will actually get passed is the element type of the
	 * array.
	 */
	if (IsA(expr, ScalarArrayOpExpr) &&
		argnum == 1)
		argtype = get_element_type(argtype);
	else if (IsA(expr, ArrayCoerceExpr) &&
			 argnum == 0)
		argtype = get_element_type(argtype);

	return argtype;
}