Mercurial > jhg
view src/org/tmatesoft/hg/internal/PathPool.java @ 506:27398bbfd543
Experiment to add a facility to check working files for actual changes
author | Artem Tikhomirov <tikhomirov.artem@gmail.com> |
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date | Fri, 30 Nov 2012 22:52:39 +0100 (2012-11-30) |
parents | 12f668401613 |
children |
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/* * Copyright (c) 2011-2012 TMate Software Ltd * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; version 2 of the License. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * For information on how to redistribute this software under * the terms of a license other than GNU General Public License * contact TMate Software at support@hg4j.com */ package org.tmatesoft.hg.internal; import java.lang.ref.SoftReference; import java.util.WeakHashMap; import org.tmatesoft.hg.util.Convertor; import org.tmatesoft.hg.util.Path; import org.tmatesoft.hg.util.PathRewrite; /** * Produces path from strings and caches (weakly) result for reuse * * @author Artem Tikhomirov * @author TMate Software Ltd. */ public class PathPool implements Path.Source, Convertor<Path> { private final WeakHashMap<CharSequence, SoftReference<Path>> cache; private final PathRewrite pathRewrite; public PathPool(PathRewrite rewrite) { pathRewrite = rewrite; cache = new WeakHashMap<CharSequence, SoftReference<Path>>(); } /* * (non-Javadoc) * @see org.tmatesoft.hg.util.Path.Source#path(java.lang.CharSequence) */ public Path path(CharSequence p) { if (p instanceof Path) { return asPath((Path) p); } p = pathRewrite.rewrite(p); return get(p, true); } /* * (non-Javadoc) * @see org.tmatesoft.hg.util.Convertor#mangle(java.lang.Object) */ public Path mangle(Path p) { return asPath(p); } // pipes path object through cache to reuse instance, if possible // TODO unify with Pool<Path> private Path asPath(Path p) { CharSequence s = pathRewrite.rewrite(p.toString()); // rewrite string, not path to avoid use of Path object as key // in case pathRewrite does nothing and returns supplied instance // Path cached = get(s, false); if (cached == null) { cache.put(s, new SoftReference<Path>(cached = p)); } return cached; } // XXX what would be parent of an empty path? // Path shall have similar functionality public Path parent(Path path) { if (path.length() == 0) { throw new IllegalArgumentException(); } for (int i = path.length() - 2 /*if path represents a dir, trailing char is slash, skip*/; i >= 0; i--) { if (path.charAt(i) == '/') { return get(path.subSequence(0, i+1).toString(), true); } } return get("", true); } // invoke when path pool is no longer in use, to ease gc work public void clear() { cache.clear(); } private Path get(CharSequence p, boolean create) { SoftReference<Path> sr = cache.get(p); Path path = sr == null ? null : sr.get(); if (path == null) { if (create) { path = Path.create(p); cache.put(p, new SoftReference<Path>(path)); } else if (sr != null) { // cached path no longer used, clear cache entry - do not wait for RefQueue to step in cache.remove(p); } } return path; } }