From ebb59131b198b693c5774dd51656fec520ddd770 Mon Sep 17 00:00:00 2001
From: Alan Conway <aconway@apache.org>
Date: Fri, 12 Sep 2008 18:07:47 +0000
Subject: Added ClusterMap and test. Moved PollableCondition, PollableQueue to
 sys.

git-svn-id: https://svn.apache.org/repos/asf/incubator/qpid/trunk/qpid@694758 13f79535-47bb-0310-9956-ffa450edef68
---
 cpp/src/qpid/sys/PollableQueue.h | 56 +++++++++++++++++++++++++++++-----------
 1 file changed, 41 insertions(+), 15 deletions(-)

(limited to 'cpp/src/qpid/sys')

diff --git a/cpp/src/qpid/sys/PollableQueue.h b/cpp/src/qpid/sys/PollableQueue.h
index 2e5d3a0d3d..153ae31135 100644
--- a/cpp/src/qpid/sys/PollableQueue.h
+++ b/cpp/src/qpid/sys/PollableQueue.h
@@ -24,7 +24,7 @@
 
 #include "qpid/sys/PollableCondition.h"
 #include "qpid/sys/Dispatcher.h"
-#include "qpid/sys/Mutex.h"
+#include "qpid/sys/Monitor.h"
 #include <boost/function.hpp>
 #include <boost/bind.hpp>
 #include <algorithm>
@@ -54,58 +54,84 @@ class PollableQueue {
     /** Callback to process a range of items. */
     typedef boost::function<void (const iterator&, const iterator&)> Callback;
 
-    /** Functor tempalate to create a Callback from a functor that handles a single item. */
+    /** @see forEach() */
     template <class F> struct ForEach {
         F handleOne;
         ForEach(const F& f) : handleOne(f) {}
         void operator()(const iterator& i, const iterator& j) const { std::for_each(i, j, handleOne); }
     };
-    /** Function to create ForEach instances */
+
+    /** Create a range callback from a functor that processes a single item. */
     template <class F> static ForEach<F> forEach(const F& f) { return ForEach<F>(f); }
     
     /** When the queue is selected by the poller, values are passed to callback cb. */
     explicit PollableQueue(const Callback& cb);
 
     /** Push a value onto the queue. Thread safe */
-    void push(const T& t) { ScopedLock l(lock); queue.push_back(t); condition.set(); }
+    void push(const T& t);
 
     /** Start polling. */ 
-    void start(const boost::shared_ptr<sys::Poller>& poller) { handle.startWatch(poller); }
+    void start(const boost::shared_ptr<sys::Poller>& poller);
 
-    /** Stop polling. */
-    void stop() { handle.stopWatch(); }
+    /** Stop polling and wait for the current callback, if any, to complete. */
+    void stop();
     
   private:
-    typedef sys::Mutex::ScopedLock ScopedLock;
-    typedef sys::Mutex::ScopedUnlock ScopedUnlock;
+    typedef sys::Monitor::ScopedLock ScopedLock;
+    typedef sys::Monitor::ScopedUnlock ScopedUnlock;
 
     void dispatch(sys::DispatchHandle&);
     
-    sys::Mutex lock;
+    sys::Monitor lock;
     Callback callback;
     PollableCondition condition;
     sys::DispatchHandle handle;
     Queue queue;
     Queue batch;
+    bool dispatching, stopped;
 };
 
 template <class T> PollableQueue<T>::PollableQueue(const Callback& cb) // FIXME aconway 2008-08-12: 
     : callback(cb),
-      handle(condition, boost::bind(&PollableQueue<T>::dispatch, this, _1), 0, 0)
+      handle(condition, boost::bind(&PollableQueue<T>::dispatch, this, _1), 0, 0),
+      dispatching(false), stopped(true)
 {}
 
+template <class T> void PollableQueue<T>::start(const boost::shared_ptr<sys::Poller>& poller) {
+    ScopedLock l(lock);
+    stopped = false;
+    handle.startWatch(poller);
+}
+
+template <class T> void PollableQueue<T>::push(const T& t) {
+    ScopedLock l(lock);
+    queue.push_back(t);
+    condition.set();
+}
+
 template <class T> void PollableQueue<T>::dispatch(sys::DispatchHandle& h) {
-    ScopedLock l(lock);         // Lock for concurrent push() 
-    batch.clear();
-    batch.swap(queue);
+    ScopedLock l(lock);
+    if (stopped) return;
+    dispatching = true;
     condition.clear();
+    batch.clear();
+    batch.swap(queue);          // Snapshot of current queue contents.
     {
         // Process outside the lock to allow concurrent push.
         ScopedUnlock u(lock);
         callback(batch.begin(), batch.end()); 
-        h.rewatch();
     }
     batch.clear();
+    dispatching = false;
+    if (stopped) lock.notifyAll();
+    else h.rewatch();
+}
+
+template <class T> void PollableQueue<T>::stop() {
+    ScopedLock l(lock);
+    handle.stopWatch();
+    stopped = true;
+    while (dispatching) lock.wait();
 }
 
 }} // namespace qpid::sys
-- 
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