tikhomirov@64: /*
tikhomirov@431:  * Copyright (c) 2011-2012 TMate Software Ltd
tikhomirov@64:  *  
tikhomirov@64:  * This program is free software; you can redistribute it and/or modify
tikhomirov@64:  * it under the terms of the GNU General Public License as published by
tikhomirov@64:  * the Free Software Foundation; version 2 of the License.
tikhomirov@64:  *
tikhomirov@64:  * This program is distributed in the hope that it will be useful,
tikhomirov@64:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
tikhomirov@64:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
tikhomirov@64:  * GNU General Public License for more details.
tikhomirov@64:  *
tikhomirov@64:  * For information on how to redistribute this software under
tikhomirov@64:  * the terms of a license other than GNU General Public License
tikhomirov@102:  * contact TMate Software at support@hg4j.com
tikhomirov@64:  */
tikhomirov@431: package org.tmatesoft.hg.internal;
tikhomirov@64: 
tikhomirov@64: import java.lang.ref.SoftReference;
tikhomirov@64: import java.util.WeakHashMap;
tikhomirov@64: 
tikhomirov@431: import org.tmatesoft.hg.util.Convertor;
tikhomirov@431: import org.tmatesoft.hg.util.Path;
tikhomirov@431: import org.tmatesoft.hg.util.PathRewrite;
tikhomirov@431: 
tikhomirov@64: 
tikhomirov@64: /**
tikhomirov@431:  * Produces path from strings and caches (weakly) result for reuse
tikhomirov@141:  * 
tikhomirov@64:  * @author Artem Tikhomirov
tikhomirov@64:  * @author TMate Software Ltd.
tikhomirov@64:  */
tikhomirov@431: public class PathPool implements Path.Source, Convertor<Path> {
tikhomirov@431: 	private final WeakHashMap<CharSequence, SoftReference<Path>> cache;
tikhomirov@64: 	private final PathRewrite pathRewrite;
tikhomirov@64: 	
tikhomirov@64: 	public PathPool(PathRewrite rewrite) {
tikhomirov@64: 		pathRewrite = rewrite;
tikhomirov@431: 		cache = new WeakHashMap<CharSequence, SoftReference<Path>>();
tikhomirov@64: 	}
tikhomirov@64: 
tikhomirov@431: 	/*
tikhomirov@431: 	 * (non-Javadoc)
tikhomirov@431: 	 * @see org.tmatesoft.hg.util.Path.Source#path(java.lang.CharSequence)
tikhomirov@431: 	 */
tikhomirov@431: 	public Path path(CharSequence p) {
tikhomirov@431: 		if (p instanceof Path) {
tikhomirov@431: 			return asPath((Path) p);
tikhomirov@431: 		}
tikhomirov@431: 		p = pathRewrite.rewrite(p);
tikhomirov@141: 		return get(p, true);
tikhomirov@141: 	}
tikhomirov@141: 
tikhomirov@431: 	/*
tikhomirov@431: 	 * (non-Javadoc)
tikhomirov@431: 	 * @see org.tmatesoft.hg.util.Convertor#mangle(java.lang.Object)
tikhomirov@431: 	 */
tikhomirov@431: 	public Path mangle(Path p) {
tikhomirov@431: 		return asPath(p);
tikhomirov@431: 	}
tikhomirov@431: 
tikhomirov@141: 	// pipes path object through cache to reuse instance, if possible
tikhomirov@231: 	// TODO unify with Pool<Path>
tikhomirov@431: 	private Path asPath(Path p) {
tikhomirov@431: 		CharSequence s = pathRewrite.rewrite(p.toString());
tikhomirov@431: 		// rewrite string, not path to avoid use of Path object as key
tikhomirov@431: 		// in case pathRewrite does nothing and returns supplied instance
tikhomirov@431: 		//
tikhomirov@141: 		Path cached = get(s, false);
tikhomirov@141: 		if (cached == null) {
tikhomirov@141: 			cache.put(s, new SoftReference<Path>(cached = p));
tikhomirov@64: 		}
tikhomirov@141: 		return cached;
tikhomirov@64: 	}
tikhomirov@64: 
tikhomirov@64: 	// XXX what would be parent of an empty path?
tikhomirov@64: 	// Path shall have similar functionality
tikhomirov@64: 	public Path parent(Path path) {
tikhomirov@64: 		if (path.length() == 0) {
tikhomirov@64: 			throw new IllegalArgumentException();
tikhomirov@64: 		}
tikhomirov@64: 		for (int i = path.length() - 2 /*if path represents a dir, trailing char is slash, skip*/; i >= 0; i--) {
tikhomirov@64: 			if (path.charAt(i) == '/') {
tikhomirov@64: 				return get(path.subSequence(0, i+1).toString(), true);
tikhomirov@64: 			}
tikhomirov@64: 		}
tikhomirov@64: 		return get("", true);
tikhomirov@64: 	}
tikhomirov@231: 	
tikhomirov@231: 	// invoke when path pool is no longer in use, to ease gc work
tikhomirov@231: 	public void clear() {
tikhomirov@231: 		cache.clear();
tikhomirov@231: 	}
tikhomirov@64: 
tikhomirov@431: 	private Path get(CharSequence p, boolean create) {
tikhomirov@64: 		SoftReference<Path> sr = cache.get(p);
tikhomirov@64: 		Path path = sr == null ? null : sr.get();
tikhomirov@64: 		if (path == null) {
tikhomirov@64: 			if (create) {
tikhomirov@64: 				path = Path.create(p);
tikhomirov@64: 				cache.put(p, new SoftReference<Path>(path));
tikhomirov@64: 			} else if (sr != null) {
tikhomirov@64: 				// cached path no longer used, clear cache entry - do not wait for RefQueue to step in
tikhomirov@64: 				cache.remove(p);
tikhomirov@64: 			}
tikhomirov@64: 		} 
tikhomirov@64: 		return path;
tikhomirov@64: 	}
tikhomirov@64: }