--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hg4j/src/main/java/org/tmatesoft/hg/repo/HgIgnore.java	Tue May 10 10:52:53 2011 +0200
@@ -0,0 +1,134 @@
+/*
+ * Copyright (c) 2010-2011 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.repo;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.regex.Pattern;
+
+import org.tmatesoft.hg.util.Path;
+
+/**
+ * Handling of ignored paths according to .hgignore configuration
+ * 
+ * @author Artem Tikhomirov
+ * @author TMate Software Ltd.
+ */
+public class HgIgnore {
+
+	private List<Pattern> entries;
+
+	HgIgnore() {
+		entries = Collections.emptyList();
+	}
+
+	/* package-local */void read(File hgignoreFile) throws IOException {
+		if (!hgignoreFile.exists()) {
+			return;
+		}
+		ArrayList<Pattern> result = new ArrayList<Pattern>(entries); // start with existing
+		String syntax = "regex"; // or "glob"
+		BufferedReader fr = new BufferedReader(new FileReader(hgignoreFile));
+		String line;
+		while ((line = fr.readLine()) != null) {
+			line = line.trim();
+			if (line.startsWith("syntax:")) {
+				syntax = line.substring("syntax:".length()).trim();
+				if (!"regex".equals(syntax) && !"glob".equals(syntax)) {
+					throw new IllegalStateException(line);
+				}
+			} else if (line.length() > 0) {
+				// shall I account for local paths in the file (i.e.
+				// back-slashed on windows)?
+				int x;
+				if ((x = line.indexOf('#')) >= 0) {
+					line = line.substring(0, x).trim();
+					if (line.length() == 0) {
+						continue;
+					}
+				}
+				if ("glob".equals(syntax)) {
+					// hgignore(5)
+					// (http://www.selenic.com/mercurial/hgignore.5.html) says slashes '\' are escape characters,
+					// hence no special  treatment of Windows path
+					// however, own attempts make me think '\' on Windows are not treated as escapes
+					line = glob2regex(line);
+				}
+				result.add(Pattern.compile(line)); // case-sensitive
+			}
+		}
+		result.trimToSize();
+		entries = result;
+	}
+
+	// note, #isIgnored(), even if queried for directories and returned positive reply, may still get
+	// a file from that ignored folder to get examined. Thus, patterns like "bin" shall match not only a folder,
+	// but any file under that folder as well
+	// Alternatively, file walker may memorize folder is ignored and uses this information for all nested files. However,
+	// this approach would require walker (a) return directories (b) provide nesting information. This may become
+	// troublesome when one walks not over io.File, but Eclipse's IResource or any other custom VFS.
+	//
+	//
+	// might be interesting, although looks like of no direct use in my case 
+	// @see http://stackoverflow.com/questions/1247772/is-there-an-equivalent-of-java-util-regex-for-glob-type-patterns
+	private String glob2regex(String line) {
+		assert line.length() > 0;
+		StringBuilder sb = new StringBuilder(line.length() + 10);
+		sb.append('^'); // help avoid matcher.find() to match 'bin' pattern in the middle of the filename
+		int start = 0, end = line.length() - 1;
+		// '*' at the beginning and end of a line are useless for Pattern
+		// XXX although how about **.txt - such globs can be seen in a config, are they valid for HgIgnore?
+		while (start <= end && line.charAt(start) == '*') start++;
+		while (end > start && line.charAt(end) == '*') end--;
+
+		for (int i = start; i <= end; i++) {
+			char ch = line.charAt(i);
+			if (ch == '.' || ch == '\\') {
+				sb.append('\\');
+			} else if (ch == '?') {
+				// simple '.' substitution might work out, however, more formally 
+				// a char class seems more appropriate to avoid accidentally
+				// matching a subdirectory with ? char (i.e. /a/b?d against /a/bad, /a/bed and /a/b/d)
+				// @see http://pubs.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_13_03
+				// quote: "The slash character in a pathname shall be explicitly matched by using one or more slashes in the pattern; 
+				// it shall neither be matched by the asterisk or question-mark special characters nor by a bracket expression" 
+				sb.append("[^/]");
+				continue;
+			} else if (ch == '*') {
+				sb.append("[^/]*?");
+				continue;
+			}
+			sb.append(ch);
+		}
+		return sb.toString();
+	}
+
+	// TODO use PathGlobMatcher
+	public boolean isIgnored(Path path) {
+		for (Pattern p : entries) {
+			if (p.matcher(path).find()) {
+				return true;
+			}
+		}
+		return false;
+	}
+}