--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/org/tmatesoft/hg/util/RegularFileStats.java	Wed Mar 21 20:40:28 2012 +0100
@@ -0,0 +1,157 @@
+/*
+ * Copyright (c) 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.util;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.TreeMap;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.tmatesoft.hg.internal.Internals;
+import org.tmatesoft.hg.internal.ProcessExecHelper;
+
+/**
+ * Utility to collect executable files and symbolic links in a directory.
+ * 
+ * 
+ * Not public as present approach (expect file but collect once per directory) may need to be made explicit
+ * 
+ * TODO post-1.0 Add Linux-specific set of tests (similar to my test-flags repository, with symlink, executable and regular file,
+ * and few revisions where link and exec flags change. +testcase when link points to non-existing file (shall not report as missing, 
+ * iow either FileInfo.exist() shall respect symlinks or WCSC account for )
+ * 
+ * TODO post-1.0 Add extraction of link modification time, see RegularFileInfo#lastModified()
+ * 
+ * @author Artem Tikhomirov
+ * @author Tmate Software Ltd.
+ */
+/*package-local*/ class RegularFileStats {
+	private boolean isExec, isSymlink;
+	private String symlinkValue;
+	private final List<String> command;
+	private final ProcessExecHelper execHelper;
+	private final Matcher linkMatcher, execMatcher;
+	
+	
+	// directory name to (short link name -> link target)
+	private Map<String, Map<String, String>> dir2links = new TreeMap<String, Map<String, String>>();
+	// directory name to set of executable file short names
+	private Map<String, Set<String>> dir2execs = new TreeMap<String, Set<String>>();
+
+
+	RegularFileStats() {
+		if (Internals.runningOnWindows()) {
+			// XXX this implementation is not yet tested against any Windows repository, 
+			// only against sample dir listings. As long as Mercurial doesn't handle Windows
+			// links, we don't really need this
+			command = Arrays.asList("cmd", "/c", "dir");
+			// Windows patterns need to work against full directory listing (I didn't find a way 
+			// to list single file with its attributes like SYMLINK) 
+			Pattern pLink = Pattern.compile("^\\S+.*\\s+<SYMLINK>\\s+(\\S.*)\\s+\\[(.+)\\]$", Pattern.MULTILINE);
+			Pattern pExec = Pattern.compile("^\\S+.*\\s+\\d+\\s+(\\S.*\\.exe)$", Pattern.MULTILINE);
+			linkMatcher = pLink.matcher("");
+			execMatcher = pExec.matcher("");
+		} else {
+			command = Arrays.asList("/bin/ls", "-l", "-Q"); // -Q is essential to get quoted name - the only way to
+			// tell exact file name (which may start or end with spaces.
+			Pattern pLink = Pattern.compile("^lrwxrwxrwx\\s.*\\s\"(.*)\"\\s+->\\s+\"(.*)\"$", Pattern.MULTILINE);
+			// pLink: group(1) is full name if single file listing (ls -l /usr/bin/java) and short name if directory listing (ls -l /usr/bin)
+			//        group(2) is link target
+			Pattern pExec = Pattern.compile("^-..[sx]..[sx]..[sx]\\s.*\\s\"(.+)\"$", Pattern.MULTILINE);
+			// pExec: group(1) is name of executable file
+			linkMatcher = pLink.matcher("");
+			execMatcher = pExec.matcher("");
+		}
+		execHelper = new ProcessExecHelper();
+	}
+
+	public void init(File f) {
+		// can't check isFile because Java would say false for a symlink with non-existing target
+		if (f.isDirectory()) {
+			// perhaps, shall just collect stats for all files and set false to exec/link flags?
+			throw new IllegalArgumentException(); // FIXME EXCEPTIONS
+		}
+		final String dirName = f.getParentFile().getAbsolutePath();
+		final String fileName = f.getName();
+		Map<String, String> links = dir2links.get(dirName);
+		Set<String> execs = dir2execs.get(dirName);
+		if (links == null || execs == null) {
+			try {
+				ArrayList<String> cmd = new ArrayList<String>(command);
+				cmd.add(dirName);
+				CharSequence result = execHelper.exec(cmd);
+				
+				if (execMatcher.reset(result).find()) {
+					execs = new HashSet<String>();
+					do {
+						execs.add(execMatcher.group(1));
+					} while (execMatcher.find());
+				} else {
+					execs = Collections.emptySet(); // indicate we tried and found nothing
+				}
+				if (linkMatcher.reset(result).find()) {
+					links = new HashMap<String, String>();
+					do {
+						links.put(linkMatcher.group(1), linkMatcher.group(2));
+					} while (linkMatcher.find());
+				} else {
+					links = Collections.emptyMap();
+				}
+				dir2links.put(dirName, links);
+				dir2execs.put(dirName, execs);
+			} catch (InterruptedException ex) {
+				// try again? ensure not too long? stop right away?
+				// FIXME EXCEPTIONS
+				throw new RuntimeException();
+			} catch (IOException ex) {
+				// FIXME EXCEPTIONS perhaps, fail silently indicating false for both x and l?
+				throw new RuntimeException();
+			}
+		}
+		isExec = execs.contains(fileName);
+		isSymlink = links.containsKey(fileName);
+		if (isSymlink) {
+			symlinkValue = links.get(fileName);
+		} else {
+			symlinkValue = null;
+		}
+	}
+
+	public boolean isExecutable() {
+		return isExec;
+	}
+	
+	public boolean isSymlink() {
+		return isSymlink;
+	}
+
+	public String getSymlinkTarget() {
+		if (isSymlink) {
+			return symlinkValue;
+		}
+		throw new UnsupportedOperationException();
+	}
+}