--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/org/tmatesoft/hg/internal/LifecycleBridge.java	Fri Dec 21 21:20:26 2012 +0100
@@ -0,0 +1,92 @@
+/*
+ * 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.internal;
+
+import org.tmatesoft.hg.util.CancelSupport;
+import org.tmatesoft.hg.util.CancelledException;
+import org.tmatesoft.hg.util.ProgressSupport;
+
+/**
+ * Bridge low-level life-cycle ({@link Lifecycle}) API with high-level one ({@link ProgressSupport} and {@link CancelSupport}).
+ * 
+ * @author Artem Tikhomirov
+ * @author TMate Software Ltd.
+ */
+public class LifecycleBridge implements Lifecycle {
+	private final ProgressSupport progressHelper;
+	private final CancelSupport cancelSupport;
+	// may be null unless #start() is invoked
+	private Callback receiver;
+	private CancelledException cancellation;
+
+	
+	public LifecycleBridge(ProgressSupport progress, CancelSupport cancel) {
+		progressHelper = progress;
+		cancelSupport = cancel;
+	}
+
+	public void start(int count, Callback callback, Object token) {
+		receiver = callback;
+		if (progressHelper != null) {
+			progressHelper.start(count);
+		}
+	}
+
+	public void finish(Object token) {
+		if (progressHelper != null) {
+			progressHelper.done();
+		}
+		receiver = null;
+	}
+
+	// XXX SHALL work without start/finish sequence because
+	// HgLogCommand invokes ChangesetTransformer#next directly (i.e. not from
+	// inside a library's #range() or similar) to process changesets in unnatural order.
+	public void nextStep() {
+		if (progressHelper != null) {
+			progressHelper.worked(1);
+		}
+		if (cancelSupport == null) {
+			return;
+		}
+		try { 
+			cancelSupport.checkCancelled();
+		} catch (CancelledException ex) {
+			if (receiver != null) {
+				receiver.stop();
+			}
+			cancellation = ex;
+		}
+	}
+
+	public void stop() {
+		if (receiver != null) {
+			receiver.stop();
+		}
+	}
+	
+	/**
+	 * @return <code>true</code> iff {@link CancelledException} was thrown and catched. Forced stop doesn't count
+	 */
+	public boolean isCancelled() {
+		return cancellation != null;
+	}
+	
+	public CancelledException getCancelOrigin() {
+		return cancellation;
+	}
+}
\ No newline at end of file