client/BlockingQueue.h, sys/ConcurrentQueue.h: merged to sys/BlockingQueue.h

 - updated all users 	  

qpid/Exception.h: Removed unimplemented clone() function.


git-svn-id: https://svn.apache.org/repos/asf/incubator/qpid/trunk/qpid@589857 13f79535-47bb-0310-9956-ffa450edef68

3 files changed, 140 insertions, 126 deletions

diff --git a/cpp/src/qpid/sys/BlockingQueue.h b/cpp/src/qpid/sys/BlockingQueue.h
new file mode 100644
index 0000000000..65196dbd9c
--- /dev/null
+++ b/cpp/src/qpid/sys/BlockingQueue.h
@@ -0,0 +1,127 @@
+#ifndef QPID_SYS_BLOCKINGQUEUE_H
+#define QPID_SYS_BLOCKINGQUEUE_H
+
+/*
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ *
+ */
+
+#include "Waitable.h"
+
+#include <queue>
+
+namespace qpid {
+namespace sys {
+
+struct QueueClosed {};
+
+template <class T>
+class BlockingQueue
+{
+    sys::Waitable lock;
+    std::queue<T> queue;
+    bool closed;
+
+public:
+    BlockingQueue() : closed(false) {}
+    ~BlockingQueue() { close(); }
+
+    /** Block until there is a value to pop */
+    T pop()
+    {
+        Waitable::ScopedLock l(lock);
+        if (!queueWait()) throw QueueClosed();
+        return popInternal();
+    }
+
+    /** Non-blocking pop. If there is a value set outValue and return
+     * true, else return false;
+     */
+    bool tryPop(T& outValue) {
+        Waitable::ScopedLock l(lock);
+        if (queue.empty()) return false;
+        outValue = popInternal();
+        return true;
+    }
+
+    /** Non-blocking pop. If there is a value return it, else return
+     * valueIfEmpty.
+     */
+    T tryPop(const T& valueIfEmpty=T()) {
+        T result=valueIfEmpty;
+        tryPop(result);
+        return result;
+    }
+
+    /** Push a value onto the queue */
+    void push(const T& t)
+    {
+        Waitable::ScopedLock l(lock);
+        queue.push(t);
+        queueNotify(0);
+    }
+
+    /**
+     * Close the queue. Throws QueueClosed in threads waiting in pop().
+     * Blocks till all waiting threads have been notified.
+     */ 
+    void close()
+    {
+        Waitable::ScopedLock l(lock);
+        if (!closed) {
+            closed = true;
+            lock.notifyAll();
+            lock.waitWaiters(); // Ensure no threads are still waiting.
+        }
+    }
+
+    /** Open a closed queue. */
+    void open() {
+        Waitable::ScopedLock l(lock);
+        closed=false;
+    }
+
+  private:
+
+    void queueNotify(size_t ignore) {
+        if (!queue.empty() && lock.hasWaiters()>ignore)
+            lock.notify();      // Notify another waiter.
+    }
+
+    bool queueWait() {
+        Waitable::ScopedWait w(lock);
+        while (!closed && queue.empty())
+            lock.wait();
+        return !queue.empty();
+    }
+
+    T popInternal() {
+        T t=queue.front();
+        queue.pop();
+        queueNotify(1);
+        return t;
+    }
+    
+};
+
+}}
+
+
+
+#endif  /*!QPID_SYS_BLOCKINGQUEUE_H*/
diff --git a/cpp/src/qpid/sys/ConcurrentQueue.h b/cpp/src/qpid/sys/ConcurrentQueue.h
deleted file mode 100644
index 43e82cadce..0000000000
--- a/cpp/src/qpid/sys/ConcurrentQueue.h
+++ /dev/null
@@ -1,111 +0,0 @@
-#ifndef QPID_SYS_CONCURRENTQUEUE_H
-#define QPID_SYS_CONCURRENTQUEUE_H
-
-/*
- *
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you 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.
- *
- */
-
-#include "qpid/sys/Waitable.h"
-#include "qpid/sys/ScopedIncrement.h"
-
-#include <boost/bind.hpp>
-
-#include <deque>
-
-namespace qpid {
-namespace sys {
-
-/**
- * Thread-safe queue that allows threads to push items onto
- * the queue concurrently with threads popping items off the
- * queue.
- *
- * Also allows consuming threads to wait until an item is available.
- */
-template <class T> class ConcurrentQueue : public Waitable {
-  public:
-    struct ShutdownException {};
-    
-    ConcurrentQueue() : shutdownFlag(false) {}
-
-    /** Waiting threads are notified by ~Waitable */
-    ~ConcurrentQueue() { shutdown(); }
-
-    bool shutdown(bool wait=true) {
-        ScopedLock l(lock);
-        if (!shutdownFlag) {
-            shutdownFlag=true;
-            lock.notifyAll();
-            if (wait) lock.waitAll();
-            shutdownFlag=true;
-            return true;
-        }
-        return false;
-    }
-
-    /** Push a data item onto the back of the queue */
-    void push(const T& data) {
-        Mutex::ScopedLock l(lock);
-        queue.push_back(data);
-        lock.notify();
-    }
-
-    /** If the queue is non-empty, pop the front item into data and
-     * return true. If the queue is empty, return false
-     */
-    bool tryPop(T& data) {
-        Mutex::ScopedLock l(lock);
-        if (shutdownFlag || queue.empty())
-            return false;
-        data = queue.front();
-        queue.pop_front();
-        return true;
-    }
-
-    /** Wait for a data item to be available.
-     * Return false if shut down.
-     */
-    bool waitPop(T& data) {
-        ScopedLock l(lock);
-        {
-            ScopedWait(*this);
-            while (!shutdownFlag && queue.empty())
-                lock.wait();
-        }
-        if (queue.empty())
-            return false;
-        data = queue.front();
-        queue.pop_front();
-        return true;
-    }
-
-    bool isShutdown() { ScopedLock l(lock); return shutdownFlag; }
-    
-  protected:
-    Waitable lock;
-  private:
-    std::deque<T> queue;
-    bool shutdownFlag;
-};
-
-}} // namespace qpid::sys
-
-
-#endif  /*!QPID_SYS_CONCURRENTQUEUE_H*/
diff --git a/cpp/src/qpid/sys/Waitable.h b/cpp/src/qpid/sys/Waitable.h
index eb71a1d742..37392ed761 100644
--- a/cpp/src/qpid/sys/Waitable.h
+++ b/cpp/src/qpid/sys/Waitable.h
@@ -29,9 +29,9 @@ namespace qpid {
 namespace sys {
 
 /**
- * A monitor that keeps track of waiting threads.
- * Threads that use a WaitLock are counted as waiters, threads that
- * use a normal ScopedLock are not considered waiters.
+ * A monitor that keeps track of waiting threads.  Threads declare a
+ * ScopedWait around wait() inside a ScopedLock to be considered
+ * waiters.
  */
 class Waitable : public Monitor {
   public:
@@ -43,24 +43,22 @@ class Waitable : public Monitor {
     struct ScopedWait {
         Waitable& w;
         ScopedWait(Waitable& w_) : w(w_) { ++w.waiters; }
-        ~ScopedWait() { --w.waiters; w.notifyAll(); }
+        ~ScopedWait() { if (--w.waiters==0) w.notifyAll(); }
     };
 
-    /** Block till all waiters have finished waiting.
-     * The calling thread does not count as a waiter.
+    /** Block till there are no more ScopedWaits.
      *@pre Must be called inside a ScopedLock but NOT a ScopedWait.
      */
-    bool waitAll(Duration timeout=TIME_INFINITE) {
-        AbsTime deadline(now(), timeout);
-        while (waiters > 0) {
-            if (!wait(deadline)) {
-                assert(timeout != TIME_INFINITE);
-                return false;
-            }
-        }
-        return true;
+    void waitWaiters() {
+        while (waiters != 0) 
+            wait();
     }
 
+    /** Returns the number of outstanding ScopedWaits.
+     * Must be called with the lock held.
+     */
+    size_t hasWaiters() { return waiters; }
+    
   private:
   friend struct ScopedWait;
     size_t waiters;