kitaev@213: /*
kitaev@213:  * Copyright (c) 2011 TMate Software Ltd
kitaev@213:  *  
kitaev@213:  * This program is free software; you can redistribute it and/or modify
kitaev@213:  * it under the terms of the GNU General Public License as published by
kitaev@213:  * the Free Software Foundation; version 2 of the License.
kitaev@213:  *
kitaev@213:  * This program is distributed in the hope that it will be useful,
kitaev@213:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
kitaev@213:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
kitaev@213:  * GNU General Public License for more details.
kitaev@213:  *
kitaev@213:  * For information on how to redistribute this software under
kitaev@213:  * the terms of a license other than GNU General Public License
kitaev@213:  * contact TMate Software at support@hg4j.com
kitaev@213:  */
kitaev@213: package org.tmatesoft.hg.util;
kitaev@213: 
kitaev@213: import java.lang.ref.SoftReference;
kitaev@213: import java.util.WeakHashMap;
kitaev@213: 
kitaev@213: 
kitaev@213: /**
kitaev@213:  * Produces path from strings and caches result for reuse
kitaev@213:  * 
kitaev@213:  * @author Artem Tikhomirov
kitaev@213:  * @author TMate Software Ltd.
kitaev@213:  */
kitaev@213: public class PathPool implements Path.Source {
kitaev@213: 	private final WeakHashMap<String, SoftReference<Path>> cache;
kitaev@213: 	private final PathRewrite pathRewrite;
kitaev@213: 	
kitaev@213: 	public PathPool(PathRewrite rewrite) {
kitaev@213: 		pathRewrite = rewrite;
kitaev@213: 		cache = new WeakHashMap<String, SoftReference<Path>>();
kitaev@213: 	}
kitaev@213: 
kitaev@213: 	public Path path(String p) {
kitaev@213: 		p = pathRewrite.rewrite(p);
kitaev@213: 		return get(p, true);
kitaev@213: 	}
kitaev@213: 
kitaev@213: 	// pipes path object through cache to reuse instance, if possible
kitaev@213: 	public Path path(Path p) {
kitaev@213: 		String s = pathRewrite.rewrite(p.toString());
kitaev@213: 		Path cached = get(s, false);
kitaev@213: 		if (cached == null) {
kitaev@213: 			cache.put(s, new SoftReference<Path>(cached = p));
kitaev@213: 		}
kitaev@213: 		return cached;
kitaev@213: 	}
kitaev@213: 
kitaev@213: 	// XXX what would be parent of an empty path?
kitaev@213: 	// Path shall have similar functionality
kitaev@213: 	public Path parent(Path path) {
kitaev@213: 		if (path.length() == 0) {
kitaev@213: 			throw new IllegalArgumentException();
kitaev@213: 		}
kitaev@213: 		for (int i = path.length() - 2 /*if path represents a dir, trailing char is slash, skip*/; i >= 0; i--) {
kitaev@213: 			if (path.charAt(i) == '/') {
kitaev@213: 				return get(path.subSequence(0, i+1).toString(), true);
kitaev@213: 			}
kitaev@213: 		}
kitaev@213: 		return get("", true);
kitaev@213: 	}
kitaev@213: 
kitaev@213: 	private Path get(String p, boolean create) {
kitaev@213: 		SoftReference<Path> sr = cache.get(p);
kitaev@213: 		Path path = sr == null ? null : sr.get();
kitaev@213: 		if (path == null) {
kitaev@213: 			if (create) {
kitaev@213: 				path = Path.create(p);
kitaev@213: 				cache.put(p, new SoftReference<Path>(path));
kitaev@213: 			} else if (sr != null) {
kitaev@213: 				// cached path no longer used, clear cache entry - do not wait for RefQueue to step in
kitaev@213: 				cache.remove(p);
kitaev@213: 			}
kitaev@213: 		} 
kitaev@213: 		return path;
kitaev@213: 	}
kitaev@213: }