Posix EventChannel implementation using epoll. Placeholder for kevents.

Dynamic thread pool EventChannelThreads to serve EventChannel.
Misc cleanup/enhancements.


git-svn-id: https://svn.apache.org/repos/asf/incubator/qpid/trunk/qpid@480582 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 119 insertions, 0 deletions

diff --git a/cpp/src/qpid/posix/EventChannelThreads.cpp b/cpp/src/qpid/posix/EventChannelThreads.cpp
new file mode 100644
index 0000000000..f97efd17e8
--- /dev/null
+++ b/cpp/src/qpid/posix/EventChannelThreads.cpp
@@ -0,0 +1,119 @@
+/*
+ *
+ * Copyright (c) 2006 The Apache Software Foundation
+ *
+ * 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.
+ *
+ */
+
+#include "EventChannelThreads.h"
+#include <qpid/sys/Runnable.h>
+#include <iostream>
+using namespace std;
+#include <boost/bind.hpp>
+
+namespace qpid {
+namespace sys {
+
+EventChannelThreads::shared_ptr EventChannelThreads::create(
+    EventChannel::shared_ptr ec)
+{
+    return EventChannelThreads::shared_ptr(new EventChannelThreads(ec));
+}
+
+EventChannelThreads::EventChannelThreads(EventChannel::shared_ptr ec) :
+    channel(ec), nWaiting(0), state(RUNNING)
+{
+    // TODO aconway 2006-11-15: Estimate initial threads based on CPUs.
+    addThread();
+}
+
+EventChannelThreads::~EventChannelThreads() {
+    shutdown();
+    join();
+}
+
+void EventChannelThreads::shutdown() 
+{
+    ScopedLock lock(*this);
+    if (state != RUNNING)       // Already shutting down.
+        return;
+    for (size_t i = 0; i < workers.size(); ++i) {
+        channel->postEvent(terminate);
+    }
+    state = TERMINATE_SENT;
+    notify();                // Wake up one join() thread.
+}
+
+void EventChannelThreads::join() 
+{
+    {
+        ScopedLock lock(*this);
+        while (state == RUNNING)    // Wait for shutdown to start.
+            wait();
+        if (state == SHUTDOWN)      // Shutdown is complete
+            return;
+        if (state == JOINING) {
+            // Someone else is doing the join.
+            while (state != SHUTDOWN)
+                wait();
+            return;
+        }
+        // I'm the  joining thread
+        assert(state == TERMINATE_SENT); 
+        state = JOINING; 
+    } // Drop the lock.
+
+    for (size_t i = 0; i < workers.size(); ++i) {
+        assert(state == JOINING); // Only this thread can change JOINING.
+        workers[i].join();
+    }
+    state = SHUTDOWN;
+    notifyAll();                // Notify other join() threaeds.
+}
+
+void EventChannelThreads::addThread() {
+    ScopedLock l(*this);
+    workers.push_back(Thread(*this));
+}
+
+void EventChannelThreads::run()
+{
+    // Start life waiting. Decrement on exit.
+    AtomicCount::ScopedIncrement inc(nWaiting);
+    try {
+        while (true) {
+            Event* e = channel->getEvent(); 
+            assert(e != 0);
+            if (e == &terminate) {
+                return;
+            }
+            AtomicCount::ScopedDecrement dec(nWaiting);
+            // I'm no longer waiting, make sure someone is.
+            if (dec == 0)
+                addThread();
+            e->dispatch();
+        }
+    }
+    catch (const std::exception& e) {
+        // TODO aconway 2006-11-15: need better logging across the board.
+        std::cerr << "EventChannelThreads::run() caught: " << e.what()
+                  << std::endl;
+    }
+    catch (...) {
+        std::cerr << "EventChannelThreads::run() caught unknown exception."
+                  << std::endl;
+    }
+}
+
+}}