--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/org/tmatesoft/hg/core/HgCatCommand.java	Wed Feb 16 20:47:56 2011 +0100
@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 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.core;
+
+import static org.tmatesoft.hg.repo.HgRepository.BAD_REVISION;
+import static org.tmatesoft.hg.repo.HgRepository.TIP;
+
+import java.io.FileNotFoundException;
+
+import org.tmatesoft.hg.repo.HgDataFile;
+import org.tmatesoft.hg.repo.HgRepository;
+import org.tmatesoft.hg.util.ByteChannel;
+
+/**
+ * Command to obtain content of a file, 'hg cat' counterpart. 
+ * 
+ * @author Artem Tikhomirov
+ * @author TMate Software Ltd.
+ */
+public class HgCatCommand {
+
+	private final HgRepository repo;
+	private Path file;
+	private int localRevision = TIP;
+	private Nodeid revision;
+
+	public HgCatCommand(HgRepository hgRepo) {
+		repo = hgRepo;
+	}
+
+	public HgCatCommand file(Path fname) {
+		file = fname;
+		return this;
+	}
+
+	// rev can't be WORKING_COPY (if allowed, need to implement in #execute())
+	public HgCatCommand revision(int rev) {
+		localRevision = rev;
+		revision = null;
+		return this;
+	}
+	
+	public HgCatCommand revision(Nodeid nodeid) {
+		revision = nodeid;
+		localRevision = BAD_REVISION;
+		return this;
+	}
+
+	public void execute(ByteChannel sink) throws Exception /*TODO own exception type*/ {
+		if (localRevision == BAD_REVISION && revision == null) {
+			throw new IllegalArgumentException("Either local file revision number or nodeid shall be specified");
+		}
+		if (file == null) {
+			throw new IllegalArgumentException("Name of the file is missing");
+		}
+		if (sink == null) {
+			throw new IllegalArgumentException();
+		}
+		HgDataFile dataFile = repo.getFileNode(file);
+		if (!dataFile.exists()) {
+			throw new FileNotFoundException();
+		}
+		int revToExtract;
+		if (revision != null) {
+			revToExtract = dataFile.getLocalRevision(revision);
+		} else {
+			revToExtract = localRevision;
+		}
+		dataFile.content(revToExtract, sink, true);
+	}
+}