1 files changed, 40 insertions, 7 deletions

diff --git a/cpp/src/qpid/broker/Queue.cpp b/cpp/src/qpid/broker/Queue.cpp
index 90b0d4cc52..42c678cb68 100644
--- a/cpp/src/qpid/broker/Queue.cpp
+++ b/cpp/src/qpid/broker/Queue.cpp
@@ -103,7 +103,8 @@ Queue::Queue(const string& _name, bool _autodelete,
     eventMgr(0),
     insertSeqNo(0),
     broker(b),
-    deleted(false)
+    deleted(false),
+    barrier(*this)
 {
     if (parent != 0 && broker != 0) {
         ManagementAgent* agent = broker->getManagementAgent();
@@ -718,14 +719,17 @@ void Queue::setLastNodeFailure()
     }
 }
 
+
 // return true if store exists, 
 bool Queue::enqueue(TransactionContext* ctxt, boost::intrusive_ptr<Message> msg, bool suppressPolicyCheck)
 {
+    ScopedUse u(barrier);
+    if (!u.acquired) return false;
+
     if (policy.get() && !suppressPolicyCheck) {
         Messages dequeues;
         {
             Mutex::ScopedLock locker(messageLock);
-            if (deleted) return false;
             policy->tryEnqueue(msg);
             policy->getPendingDequeues(dequeues);
         }
@@ -765,9 +769,12 @@ void Queue::enqueueAborted(boost::intrusive_ptr<Message> msg)
 // return true if store exists, 
 bool Queue::dequeue(TransactionContext* ctxt, const QueuedMessage& msg)
 {
+    ScopedUse u(barrier);
+    if (!u.acquired) return false;
+
     {
         Mutex::ScopedLock locker(messageLock);
-        if (deleted || !isEnqueued(msg)) return false;
+        if (!isEnqueued(msg)) return false;
         if (!ctxt) { 
             dequeued(msg);
         }
@@ -893,10 +900,10 @@ void Queue::destroy()
             popAndDequeue();
         }
         alternateExchange->decAlternateUsers();
-        deleted = true;
     }
 
     if (store) {
+        barrier.destroy();
         store->flush(*this);
         store->destroy(*this);
         store = 0;//ensure we make no more calls to the store for this queue
@@ -1172,8 +1179,34 @@ void Queue::checkNotDeleted()
     }
 }
 
-bool Queue::isValid()
+void Queue::flush()
 {
-    Mutex::ScopedLock locker(messageLock);
-    return !deleted;
+    ScopedUse u(barrier);
+    if (u.acquired && store) store->flush(*this);
+}
+
+Queue::UsageBarrier::UsageBarrier(Queue& q) : parent(q), count(0) {}
+
+bool Queue::UsageBarrier::acquire()
+{
+    Monitor::ScopedLock l(parent.messageLock);
+    if (parent.deleted) {
+        return false;
+    } else {
+        ++count;
+        return true;
+    }
+}
+
+void Queue::UsageBarrier::release()
+{
+    Monitor::ScopedLock l(parent.messageLock);
+    if (--count == 0) parent.messageLock.notifyAll();
+}
+
+void Queue::UsageBarrier::destroy()
+{
+    Monitor::ScopedLock l(parent.messageLock);
+    parent.deleted = true;
+    while (count) parent.messageLock.wait();
 }