/*
 *	PROGRAM:	JRD Access Method
 *	MODULE:		rlck.cpp
 *	DESCRIPTION:	Record and Relation Lock Manager
 *
 * The contents of this file are subject to the Interbase Public
 * License Version 1.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy
 * of the License at http://www.Inprise.com/IPL.html
 *
 * Software distributed under the License is distributed on an
 * "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express
 * or implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * The Original Code was created by Inprise Corporation
 * and its predecessors. Portions created by Inprise Corporation are
 * Copyright (C) Inprise Corporation.
 *
 * All Rights Reserved.
 * Contributor(s): ______________________________________.
 * 2001.07.06 Sean Leyne - Code Cleanup, removed "#ifdef READONLY_DATABASE"
 *                         conditionals, as the engine now fully supports
 *                         readonly databases.
 */

#include "firebird.h"
#include "../jrd/tra.h"
#include "../jrd/lck.h"
#include "../jrd/err_proto.h"
#include "../jrd/lck_proto.h"
#include "../jrd/rlck_proto.h"

using namespace Jrd;
using namespace Firebird;

Lock* RLCK_reserve_relation(thread_db* tdbb, jrd_tra* transaction, jrd_rel* relation, bool write_flag)
{
/**************************************
 *
 *	R L C K _ r e s e r v e _ r e l a t i o n
 *
 **************************************
 *
 * Functional description
 *	Lock a relation within a transaction.  If the relation
 *	is already locked at a lower level, upgrade the lock.
 *
 **************************************/
	SET_TDBB(tdbb);

	if (transaction->tra_flags & TRA_system)
		return NULL;

	// hvlad: virtual relations always writable, all kind of GTT's are writable
	// at read-only transactions at read-write databases, GTT's with ON COMMIT
	// DELETE ROWS clause is writable at read-only databases.

	if (write_flag && tdbb->getDatabase()->readOnly() &&
		!relation->isVirtual() && !(relation->rel_flags & REL_temp_tran))
	{
		ERR_post(Arg::Gds(isc_read_only_database));
	}

	if (write_flag && (transaction->tra_flags & TRA_readonly) &&
		!relation->isVirtual() && !relation->isTemporary())
	{
		ERR_post(Arg::Gds(isc_read_only_trans));
	}

	Lock* lock = RLCK_transaction_relation_lock(tdbb, transaction, relation);

	// Next, figure out what kind of lock we need

	USHORT level;
	if (transaction->tra_flags & TRA_degree3)
	{
		if (write_flag)
			level = LCK_EX;
		else
			level = LCK_PR;
	}
	else
	{
		if (write_flag)
			level = LCK_SW;
		else
			level = LCK_none;
	}

	// If the lock is already "good enough", we're done

	if (level <= lock->lck_logical)
		return lock;

	// Get lock

	USHORT result;
	if (lock->lck_logical)
		result = LCK_convert(tdbb, lock, level, transaction->getLockWait());
	else
		result = LCK_lock(tdbb, lock, level, transaction->getLockWait());
	if (!result)
		ERR_punt();

	return lock;
}


Lock* RLCK_transaction_relation_lock(thread_db* tdbb, jrd_tra* transaction, jrd_rel* relation)
{
/**************************************
 *
 *	R L C K _ t r a n s a c t i o n _ r e l a t i o n _ l o c k
 *
 **************************************
 *
 * Functional description
 *	Take out a relation lock within the context of
 *	a transaction.
 *
 **************************************/
	SET_TDBB(tdbb);

	const ULONG relId = relation->rel_id;

	Lock* lock;
	vec<Lock*>* vector = transaction->tra_relation_locks;
	if (vector && (relId < vector->count()) && (lock = (*vector)[relId]))
	{
		return lock;
	}

	vector = transaction->tra_relation_locks =
		vec<Lock*>::newVector(*transaction->tra_pool, transaction->tra_relation_locks, relId + 1);

	const USHORT relLockLen = relation->getRelLockKeyLength();
	lock = FB_NEW_RPT(*transaction->tra_pool, relLockLen) Lock(tdbb, relLockLen, LCK_relation);
	relation->getRelLockKey(tdbb, &lock->lck_key.lck_string[0]);
	// enter all relation locks into the intra-process lock manager and treat
	// them as compatible within the attachment according to IPLM rules
	lock->lck_compatible = tdbb->getAttachment();
	// for relations locked within a transaction, add a second level of
	// compatibility within the intra-process lock manager which specifies
	// that relation locks are incompatible with locks taken out by other
	// transactions, if a transaction is specified
	lock->lck_compatible2 = transaction;

	(*vector)[relId] = lock;

	return lock;
}