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diff --git a/util/concurrency/synchronization.h b/util/concurrency/synchronization.h
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+// synchronization.h
+
+/*    Copyright 2010 10gen Inc.
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+
+#pragma once
+
+#include <boost/thread/condition.hpp>
+#include "mutex.h"
+
+namespace mongo {
+
+    /*
+     * A class to establish a synchronization point between two threads. One thread is the waiter and one is
+     * the notifier. After the notification event, both proceed normally.
+     *
+     * This class is thread-safe.
+     */
+    class Notification {
+    public:
+        Notification();
+        ~Notification();
+
+        /*
+         * Blocks until the method 'notifyOne()' is called.
+         */
+        void waitToBeNotified();
+
+        /*
+         * Notifies the waiter of '*this' that it can proceed.  Can only be called once.
+         */
+        void notifyOne();
+
+    private:
+        mongo::mutex _mutex;          // protects state below
+        bool _notified;               // was notifyOne() issued?
+        boost::condition _condition;  // cond over _notified being true
+    };
+
+    /** establishes a synchronization point between threads. N threads are waits and one is notifier.
+        threadsafe.
+    */
+    class NotifyAll : boost::noncopyable {
+    public:
+        NotifyAll();
+
+        /** awaits the next notifyAll() call by another thread. notifications that precede this
+            call are ignored -- we are looking for a fresh event.
+        */
+        void wait();
+
+        /** may be called multiple times. notifies all waiters */
+        void notifyAll();
+
+    private:
+        mongo::mutex _mutex;
+        unsigned long long _counter;
+        boost::condition _condition;
+    };
+
+} // namespace mongo