regproc.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

	 * certainly there are no schemas other than pg_catalog).
	 */
	if (IsBootstrapProcessingMode())
	{
		int			matches = 0;
		Relation	hdesc;
		ScanKeyData skey[1];
		SysScanDesc sysscan;
		HeapTuple	tuple;

		ScanKeyInit(&skey[0],
					Anum_pg_operator_oprname,
					BTEqualStrategyNumber, F_NAMEEQ,
					CStringGetDatum(opr_name_or_oid));

		hdesc = heap_open(OperatorRelationId, AccessShareLock);
		sysscan = systable_beginscan(hdesc, OperatorNameNspIndexId, true,
									 SnapshotNow, 1, skey);

		while (HeapTupleIsValid(tuple = systable_getnext(sysscan)))
		{
			result = HeapTupleGetOid(tuple);
			if (++matches > 1)
				break;
		}

		systable_endscan(sysscan);
		heap_close(hdesc, AccessShareLock);

		if (matches == 0)
			ereport(ERROR,
					(errcode(ERRCODE_UNDEFINED_FUNCTION),
					 errmsg("operator does not exist: %s", opr_name_or_oid)));
		else if (matches > 1)
			ereport(ERROR,
					(errcode(ERRCODE_AMBIGUOUS_FUNCTION),
					 errmsg("more than one operator named %s",
							opr_name_or_oid)));

		PG_RETURN_OID(result);
	}

	/*
	 * Normal case: parse the name into components and see if it matches any
	 * pg_operator entries in the current search path.
	 */
	names = stringToQualifiedNameList(opr_name_or_oid, "regoperin");
	clist = OpernameGetCandidates(names, '\0');

	if (clist == NULL)
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_FUNCTION),
				 errmsg("operator does not exist: %s", opr_name_or_oid)));
	else if (clist->next != NULL)
		ereport(ERROR,
				(errcode(ERRCODE_AMBIGUOUS_FUNCTION),
				 errmsg("more than one operator named %s",
						opr_name_or_oid)));

	result = clist->oid;

	PG_RETURN_OID(result);
}

/*
 * regoperout		- converts operator OID to "opr_name"
 */
Datum
regoperout(PG_FUNCTION_ARGS)
{
	Oid			oprid = PG_GETARG_OID(0);
	char	   *result;
	HeapTuple	opertup;

	if (oprid == InvalidOid)
	{
		result = pstrdup("0");
		PG_RETURN_CSTRING(result);
	}

	opertup = SearchSysCache(OPEROID,
							 ObjectIdGetDatum(oprid),
							 0, 0, 0);

	if (HeapTupleIsValid(opertup))
	{
		Form_pg_operator operform = (Form_pg_operator) GETSTRUCT(opertup);
		char	   *oprname = NameStr(operform->oprname);

		/*
		 * In bootstrap mode, skip the fancy namespace stuff and just return
		 * the oper name.  (This path is only needed for debugging output
		 * anyway.)
		 */
		if (IsBootstrapProcessingMode())
			result = pstrdup(oprname);
		else
		{
			FuncCandidateList clist;

			/*
			 * Would this oper be found (uniquely!) by regoperin? If not,
			 * qualify it.
			 */
			clist = OpernameGetCandidates(list_make1(makeString(oprname)),
										  '\0');
			if (clist != NULL && clist->next == NULL &&
				clist->oid == oprid)
				result = pstrdup(oprname);
			else
			{
				const char *nspname;

				nspname = get_namespace_name(operform->oprnamespace);
				nspname = quote_identifier(nspname);
				result = (char *) palloc(strlen(nspname) + strlen(oprname) + 2);
				sprintf(result, "%s.%s", nspname, oprname);
			}
		}

		ReleaseSysCache(opertup);
	}
	else
	{
		/*
		 * If OID doesn't match any pg_operator entry, return it numerically
		 */
		result = (char *) palloc(NAMEDATALEN);
		snprintf(result, NAMEDATALEN, "%u", oprid);
	}

	PG_RETURN_CSTRING(result);
}

/*
 *		regoperrecv			- converts external binary format to regoper
 */
Datum
regoperrecv(PG_FUNCTION_ARGS)
{
	/* Exactly the same as oidrecv, so share code */
	return oidrecv(fcinfo);
}

/*
 *		regopersend			- converts regoper to binary format
 */
Datum
regopersend(PG_FUNCTION_ARGS)
{
	/* Exactly the same as oidsend, so share code */
	return oidsend(fcinfo);
}


/*
 * regoperatorin		- converts "oprname(args)" to operator OID
 *
 * We also accept a numeric OID, for symmetry with the output routine.
 *
 * '0' signifies unknown (OID 0).  In all other cases, the input must
 * match an existing pg_operator entry.
 */
Datum
regoperatorin(PG_FUNCTION_ARGS)
{
	char	   *opr_name_or_oid = PG_GETARG_CSTRING(0);
	Oid			result = InvalidOid;
	List	   *names;
	int			nargs;
	Oid			argtypes[FUNC_MAX_ARGS];
	char		oprkind;
	FuncCandidateList clist;

	/* '0' ? */
	if (strcmp(opr_name_or_oid, "0") == 0)
		PG_RETURN_OID(InvalidOid);

	/* Numeric OID? */
	if (opr_name_or_oid[0] >= '0' &&
		opr_name_or_oid[0] <= '9' &&
		strspn(opr_name_or_oid, "0123456789") == strlen(opr_name_or_oid))
	{
		result = DatumGetObjectId(DirectFunctionCall1(oidin,
										  CStringGetDatum(opr_name_or_oid)));
		PG_RETURN_OID(result);
	}

	/*
	 * Else it's a name and arguments.  Parse the name and arguments, look up
	 * potential matches in the current namespace search list, and scan to see
	 * which one exactly matches the given argument types.	(There will not be
	 * more than one match.)
	 *
	 * XXX at present, this code will not work in bootstrap mode, hence this
	 * datatype cannot be used for any system column that needs to receive
	 * data during bootstrap.
	 */
	parseNameAndArgTypes(opr_name_or_oid, "regoperatorin", true,
						 &names, &nargs, argtypes);
	if (nargs == 1)
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_PARAMETER),
				 errmsg("missing argument"),
				 errhint("Use NONE to denote the missing argument of a unary operator.")));
	if (nargs != 2)
		ereport(ERROR,
				(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
				 errmsg("too many arguments"),
				 errhint("Provide two argument types for operator.")));

	if (argtypes[0] == InvalidOid)
		oprkind = 'l';
	else if (argtypes[1] == InvalidOid)
		oprkind = 'r';
	else
		oprkind = 'b';

	clist = OpernameGetCandidates(names, oprkind);

	for (; clist; clist = clist->next)
	{
		if (memcmp(clist->args, argtypes, 2 * sizeof(Oid)) == 0)
			break;
	}

	if (clist == NULL)
		ereport(ERROR,
				(errcode(ERRCODE_UNDEFINED_FUNCTION),
				 errmsg("operator does not exist: %s", opr_name_or_oid)));

	result = clist->oid;

	PG_RETURN_OID(result);
}

/*
 * format_operator		- converts operator OID to "opr_name(args)"
 *
 * This exports the useful functionality of regoperatorout for use
 * in other backend modules.  The result is a palloc'd string.
 */
char *
format_operator(Oid operator_oid)
{
	char	   *result;
	HeapTuple	opertup;

	opertup = SearchSysCache(OPEROID,
							 ObjectIdGetDatum(operator_oid),
							 0, 0, 0);

	if (HeapTupleIsValid(opertup))
	{
		Form_pg_operator operform = (Form_pg_operator) GETSTRUCT(opertup);
		char	   *oprname = NameStr(operform->oprname);
		char	   *nspname;
		StringInfoData buf;

		/* XXX no support here for bootstrap mode */

		initStringInfo(&buf);

		/*
		 * Would this oper be found (given the right args) by regoperatorin?
		 * If not, we need to qualify it.
		 */
		if (!OperatorIsVisible(operator_oid))
		{
			nspname = get_namespace_name(operform->oprnamespace);
			appendStringInfo(&buf, "%s.",
							 quote_identifier(nspname));
		}

		appendStringInfo(&buf, "%s(", oprname);

		if (operform->oprleft)
			appendStringInfo(&buf, "%s,",
							 format_type_be(operform->oprleft));
		else
			appendStringInfo(&buf, "NONE,");

		if (operform->oprright)
			appendStringInfo(&buf, "%s)",
							 format_type_be(operform->oprright));
		else
			appendStringInfo(&buf, "NONE)");

		result = buf.data;

		ReleaseSysCache(opertup);
	}
	else
	{
		/*
		 * If OID doesn't match any pg_operator entry, return it numerically
		 */
		result = (char *) palloc(NAMEDATALEN);
		snprintf(result, NAMEDATALEN, "%u", operator_oid);
	}

	return result;
}

/*
 * regoperatorout		- converts operator OID to "opr_name(args)"
 */
Datum
regoperatorout(PG_FUNCTION_ARGS)
{
	Oid			oprid = PG_GETARG_OID(0);
	char	   *result;

	if (oprid == InvalidOid)
		result = pstrdup("0");
	else
		result = format_operator(oprid);

	PG_RETURN_CSTRING(result);
}

/*
 *		regoperatorrecv			- converts external binary format to regoperator
 */
Datum
regoperatorrecv(PG_FUNCTION_ARGS)
{
	/* Exactly the same as oidrecv, so share code */
	return oidrecv(fcinfo);
}

/*
 *		regoperatorsend			- converts regoperator to binary format
 */
Datum
regoperatorsend(PG_FUNCTION_ARGS)
{
	/* Exactly the same as oidsend, so share code */
	return oidsend(fcinfo);
}


/*
 * regclassin		- converts "classname" to class OID
 *
 * We also accept a numeric OID, for symmetry with the output routine.
 *
 * '-' signifies unknown (OID 0).  In all other cases, the input must
 * match an existing pg_class entry.
 */
Datum
regclassin(PG_FUNCTION_ARGS)
{
	char	   *class_name_or_oid = PG_GETARG_CSTRING(0);
	Oid			result = InvalidOid;
	List	   *names;

	/* '-' ? */
	if (strcmp(class_name_or_oid, "-") == 0)
		PG_RETURN_OID(InvalidOid);

	/* Numeric OID? */
	if (class_name_or_oid[0] >= '0' &&
		class_name_or_oid[0] <= '9' &&
		strspn(class_name_or_oid, "0123456789") == strlen(class_name_or_oid))
	{
		result = DatumGetObjectId(DirectFunctionCall1(oidin,
										CStringGetDatum(class_name_or_oid)));
		PG_RETURN_OID(result);
	}

	/* Else it's a name, possibly schema-qualified */

	/*
	 * In bootstrap mode we assume the given name is not schema-qualified, and
	 * just search pg_class for a match.  This is needed for initializing
	 * other system catalogs (pg_namespace may not exist yet, and certainly
	 * there are no schemas other than pg_catalog).
	 */
	if (IsBootstrapProcessingMode())
	{
		Relation	hdesc;
		ScanKeyData skey[1];
		SysScanDesc sysscan;
		HeapTuple	tuple;

		ScanKeyInit(&skey[0],
					Anum_pg_class_relname,
					BTEqualStrategyNumber, F_NAMEEQ,
					CStringGetDatum(class_name_or_oid));

		hdesc = heap_open(RelationRelationId, AccessShareLock);
		sysscan = systable_beginscan(hdesc, ClassNameNspIndexId, true,
									 SnapshotNow, 1, skey);

		if (HeapTupleIsValid(tuple = systable_getnext(sysscan)))
			result = HeapTupleGetOid(tuple);
		else
			ereport(ERROR,
					(errcode(ERRCODE_UNDEFINED_TABLE),
			   errmsg("relation \"%s\" does not exist", class_name_or_oid)));

		/* We assume there can be only one match */

		systable_endscan(sysscan);
		heap_close(hdesc, AccessShareLock);

		PG_RETURN_OID(result);
	}

	/*
	 * Normal case: parse the name into components and see if it matches any
	 * pg_class entries in the current search path.
	 */
	names = stringToQualifiedNameList(class_name_or_oid, "regclassin");

	result = RangeVarGetRelid(makeRangeVarFromNameList(names), false);

	PG_RETURN_OID(result);
}

/*
 * regclassout		- converts class OID to "class_name"
 */
Datum
regclassout(PG_FUNCTION_ARGS)
{
	Oid			classid = PG_GETARG_OID(0);
	char	   *result;
	HeapTuple	classtup;

	if (classid == InvalidOid)
	{