tikhomirov@610: /*
tikhomirov@610:  * Copyright (c) 2013 TMate Software Ltd
tikhomirov@610:  *  
tikhomirov@610:  * This program is free software; you can redistribute it and/or modify
tikhomirov@610:  * it under the terms of the GNU General Public License as published by
tikhomirov@610:  * the Free Software Foundation; version 2 of the License.
tikhomirov@610:  *
tikhomirov@610:  * This program is distributed in the hope that it will be useful,
tikhomirov@610:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
tikhomirov@610:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
tikhomirov@610:  * GNU General Public License for more details.
tikhomirov@610:  *
tikhomirov@610:  * For information on how to redistribute this software under
tikhomirov@610:  * the terms of a license other than GNU General Public License
tikhomirov@610:  * contact TMate Software at support@hg4j.com
tikhomirov@610:  */
tikhomirov@610: package org.tmatesoft.hg.internal;
tikhomirov@610: 
tikhomirov@610: import org.tmatesoft.hg.core.Nodeid;
tikhomirov@610: import org.tmatesoft.hg.core.SessionContext;
tikhomirov@610: import org.tmatesoft.hg.repo.HgRepository;
tikhomirov@628: import org.tmatesoft.hg.repo.HgRuntimeException;
tikhomirov@610: 
tikhomirov@610: /**
tikhomirov@610:  * Track changes to a repository based on recent changelog revision.
tikhomirov@610:  * TODO shall be merged with {@link RevlogChangeMonitor} and {@link FileChangeMonitor} into 
tikhomirov@610:  * a single facility available from {@link SessionContext}
tikhomirov@610:  * 
tikhomirov@610:  * @author Artem Tikhomirov
tikhomirov@610:  * @author TMate Software Ltd.
tikhomirov@610:  */
tikhomirov@610: public class ChangelogMonitor {
tikhomirov@610: 	private final HgRepository repo;
tikhomirov@610: 	private int changelogRevCount = -1;
tikhomirov@610: 	private Nodeid changelogLastRev = null;
tikhomirov@610: 	
tikhomirov@610: 	public ChangelogMonitor(HgRepository hgRepo) {
tikhomirov@610: 		repo = hgRepo;
tikhomirov@610: 	}
tikhomirov@610: 	
tikhomirov@610: 	// memorize the state of the repository's changelog
tikhomirov@628: 	public void touch() throws HgRuntimeException {
tikhomirov@610: 		changelogRevCount = repo.getChangelog().getRevisionCount();
tikhomirov@610: 		changelogLastRev = safeGetRevision(changelogRevCount-1);
tikhomirov@610: 	}
tikhomirov@610: 	
tikhomirov@610: 	// if present state doesn't match the one we remember
tikhomirov@628: 	public boolean isChanged() throws HgRuntimeException {
tikhomirov@610: 		int rc = repo.getChangelog().getRevisionCount();
tikhomirov@610: 		if (rc != changelogRevCount) {
tikhomirov@610: 			return true;
tikhomirov@610: 		}
tikhomirov@610: 		Nodeid r = safeGetRevision(rc-1);
tikhomirov@610: 		return !r.equals(changelogLastRev);
tikhomirov@610: 	}
tikhomirov@610: 	
tikhomirov@610: 	// handles empty repository case
tikhomirov@628: 	private Nodeid safeGetRevision(int revIndex) throws HgRuntimeException {
tikhomirov@610: 		if (revIndex >= 0) {
tikhomirov@610: 			return repo.getChangelog().getRevision(revIndex);
tikhomirov@610: 		}
tikhomirov@610: 		return Nodeid.NULL;
tikhomirov@610: 	}
tikhomirov@610: }