tikhomirov@607: /*
tikhomirov@607:  * Copyright (c) 2013 TMate Software Ltd
tikhomirov@607:  *  
tikhomirov@607:  * This program is free software; you can redistribute it and/or modify
tikhomirov@607:  * it under the terms of the GNU General Public License as published by
tikhomirov@607:  * the Free Software Foundation; version 2 of the License.
tikhomirov@607:  *
tikhomirov@607:  * This program is distributed in the hope that it will be useful,
tikhomirov@607:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
tikhomirov@607:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
tikhomirov@607:  * GNU General Public License for more details.
tikhomirov@607:  *
tikhomirov@607:  * For information on how to redistribute this software under
tikhomirov@607:  * the terms of a license other than GNU General Public License
tikhomirov@607:  * contact TMate Software at support@hg4j.com
tikhomirov@607:  */
tikhomirov@607: package org.tmatesoft.hg.internal;
tikhomirov@607: 
tikhomirov@607: import java.io.File;
tikhomirov@607: import java.util.WeakHashMap;
tikhomirov@607: 
tikhomirov@607: /**
tikhomirov@607:  * Detect changes to revlog files. Not a general file change monitoring as we utilize the fact revlogs are append-only (and even in case
tikhomirov@607:  * of stripped-off tail revisions, with e.g. mq, detection approach is still valid).
tikhomirov@607:  * 
tikhomirov@607:  * @author Artem Tikhomirov
tikhomirov@607:  * @author TMate Software Ltd.
tikhomirov@607:  */
tikhomirov@607: public class RevlogChangeMonitor {
tikhomirov@607: 	
tikhomirov@607: 	private final WeakHashMap<File, Long> lastKnownSize;
tikhomirov@621: 	private final WeakHashMap<File, Long> lastKnownTime;
tikhomirov@607: 	private final File soleFile;
tikhomirov@621: 	private long soleFileSize = -1;
tikhomirov@621: 	private long soleFileTime = -1;
tikhomirov@607: 	
tikhomirov@621: 	// use single for multiple files. TODO [1.2] repository/session context shall provide
tikhomirov@607: 	// alternative (configurable) implementations, so that Java7 users may supply better one
tikhomirov@607: 	public RevlogChangeMonitor() {
tikhomirov@607: 		lastKnownSize = new WeakHashMap<File, Long>();
tikhomirov@621: 		lastKnownTime= new WeakHashMap<File, Long>();
tikhomirov@607: 		soleFile = null;
tikhomirov@607: 	}
tikhomirov@607: 	
tikhomirov@607: 	public RevlogChangeMonitor(File f) {
tikhomirov@607: 		assert f != null;
tikhomirov@621: 		lastKnownSize = lastKnownTime = null;
tikhomirov@607: 		soleFile = f;
tikhomirov@607: 	}
tikhomirov@607: 	
tikhomirov@607: 	public void touch(File f) {
tikhomirov@607: 		assert f != null;
tikhomirov@607: 		if (lastKnownSize == null) {
tikhomirov@607: 			assert f == soleFile;
tikhomirov@621: 			soleFileSize = f.length();
tikhomirov@621: 			soleFileTime = f.lastModified();
tikhomirov@607: 		} else {
tikhomirov@607: 			lastKnownSize.put(f, f.length());
tikhomirov@621: 			lastKnownTime.put(f, f.lastModified());
tikhomirov@607: 		}
tikhomirov@607: 	}
tikhomirov@607: 	
tikhomirov@607: 	public boolean hasChanged(File f) {
tikhomirov@607: 		assert f != null;
tikhomirov@607: 		if (lastKnownSize == null) {
tikhomirov@607: 			assert f == soleFile;
tikhomirov@621: 			return soleFileSize != f.length() || soleFileTime != f.lastModified();
tikhomirov@607: 		} else {
tikhomirov@607: 			Long lastSize = lastKnownSize.get(f);
tikhomirov@621: 			Long lastTime = lastKnownTime.get(f);
tikhomirov@621: 			if (lastSize == null || lastTime == null) {
tikhomirov@607: 				return true;
tikhomirov@607: 			}
tikhomirov@621: 			return f.length() != lastSize || f.lastModified() != lastTime;
tikhomirov@607: 		}
tikhomirov@607: 	}
tikhomirov@607: }