--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dwt/internal/Lock.d	Sat Aug 09 17:00:02 2008 +0200
@@ -0,0 +1,92 @@
+/*******************************************************************************
+ * Copyright (c) 2000, 2005 IBM Corporation and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ *
+ * Port to the D programming language:
+ *     Frank Benoit <benoit@tionex.de>
+ *******************************************************************************/
+module dwt.internal.Lock;
+
+import tango.core.Thread;
+import tango.core.sync.Mutex;
+import tango.core.sync.Condition;
+import tango.core.Exception;
+
+import dwt.dwthelper.utils;
+
+/**
+ * Instance of this represent a recursive monitor.
+ */
+public class Lock
+{
+    int count, waitCount;
+    Thread owner;
+    Mutex mutex;
+    Condition cond;
+
+    public this ()
+    {
+        mutex = new Mutex;
+        cond = new Condition(mutex);
+    }
+
+    /**
+     * Locks the monitor and returns the lock count. If
+     * the lock is owned by another thread, wait until
+     * the lock is released.
+     *
+     * @return the lock count
+     */
+    public int lock ()
+    {
+        synchronized (mutex)
+        {
+            Thread current = Thread.getThis();
+            if (owner !is current)
+            {
+                waitCount++;
+                while (count > 0)
+                {
+                    try
+                    {
+                        cond.wait();
+                    }
+                    catch (SyncException e)
+                    {
+                    /* Wait forever, just like synchronized blocks */
+                    }
+                }
+                --waitCount;
+                owner = current;
+            }
+            return ++count;
+        }
+    }
+
+    /**
+     * Unlocks the monitor. If the current thread is not
+     * the monitor owner, do nothing.
+     */
+    public void unlock ()
+    {
+        synchronized (mutex)
+        {
+            Thread current = Thread.getThis();
+            if (owner is current)
+            {
+                if (--count is 0)
+                {
+                    owner = null;
+                    if (waitCount > 0)
+                        cond.notifyAll();
+                }
+            }
+        }
+    }
+}