1 files changed, 179 insertions, 0 deletions
diff --git a/cpp/src/qpid/sys/Timer.cpp b/cpp/src/qpid/sys/Timer.cpp
new file mode 100644
index 0000000000..c18fd93538
--- /dev/null
+++ b/cpp/src/qpid/sys/Timer.cpp
@@ -0,0 +1,179 @@
+/*
+ *
+ * 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/Timer.h"
+#include "qpid/sys/Mutex.h"
+#include "qpid/log/Statement.h"
+
+#include <numeric>
+
+using boost::intrusive_ptr;
+using std::max;
+
+namespace qpid {
+namespace sys {
+
+TimerTask::TimerTask(Duration timeout) :
+    sortTime(AbsTime::FarFuture()),
+    period(timeout),
+    nextFireTime(AbsTime::now(), timeout),
+    cancelled(false)
+{}
+
+TimerTask::TimerTask(AbsTime time) :
+    sortTime(AbsTime::FarFuture()),
+    period(0),
+    nextFireTime(time),
+    cancelled(false)
+{}
+
+TimerTask::~TimerTask() {}
+
+bool TimerTask::readyToFire() const {
+    return !(nextFireTime > AbsTime::now());
+}
+
+void TimerTask::fireTask() {
+    cancelled = true;
+    fire();
+}
+
+// This can only be used to setup the next fire time. After the Timer has already fired
+void TimerTask::setupNextFire() {
+    if (period && readyToFire()) {
+        nextFireTime = max(AbsTime::now(), AbsTime(nextFireTime, period));
+        cancelled = false;
+    } else {
+        QPID_LOG(error, "Couldn't setup next timer firing: " << Duration(nextFireTime, AbsTime::now()) << "[" << period << "]");
+    }
+}
+
+// Only allow tasks to be delayed
+void TimerTask::restart() { nextFireTime = max(nextFireTime, AbsTime(AbsTime::now(), period)); }
+
+void TimerTask::cancel() {
+    ScopedLock<Mutex> l(callbackLock);
+    cancelled = true;
+}
+
+Timer::Timer() :
+    active(false) 
+{
+    start();
+}
+
+Timer::~Timer() 
+{
+    stop();
+}
+
+// TODO AStitcher 21/08/09 The threshholds for emitting warnings are a little arbitrary
+void Timer::run()
+{
+    Monitor::ScopedLock l(monitor);
+    while (active) {
+        if (tasks.empty()) {
+            monitor.wait();
+        } else {
+            intrusive_ptr<TimerTask> t = tasks.top();
+            tasks.pop();
+            assert(!(t->nextFireTime < t->sortTime));
+
+            // warn on extreme lateness
+            AbsTime start(AbsTime::now());
+            Duration delay(t->sortTime, start);
+            {
+            ScopedLock<Mutex> l(t->callbackLock);
+            if (t->cancelled) {
+                if (delay > 500 * TIME_MSEC) {
+                    QPID_LOG(debug, "cancelled Timer woken up " << delay / TIME_MSEC << "ms late");
+                }
+                continue;
+            } else if(Duration(t->nextFireTime, start) >= 0) {
+                Monitor::ScopedUnlock u(monitor);
+                t->fireTask();
+                // Warn on callback overrun
+                AbsTime end(AbsTime::now());
+                Duration overrun(tasks.top()->nextFireTime, end);
+                bool late = delay > 50 * TIME_MSEC;
+                bool overran = overrun > 2 * TIME_MSEC;
+                if (late)
+                if (overran) {
+                    QPID_LOG(warning,
+                        "Timer woken up " << delay / TIME_MSEC << "ms late, "
+                        "overrunning by " << overrun / TIME_MSEC << "ms [taking "
+                        << Duration(start, end) << "]");
+                } else {
+                    QPID_LOG(warning, "Timer woken up " << delay / TIME_MSEC << "ms late");
+                } else if (overran) {
+                    QPID_LOG(warning,
+                        "Timer callback overran by " << overrun / TIME_MSEC << "ms [taking "
+                        << Duration(start, end) << "]");
+                }
+                continue;
+            } else {
+                // If the timer was adjusted into the future it might no longer
+                // be the next event, so push and then get top to make sure
+                // You can only push events into the future
+                t->sortTime = t->nextFireTime;
+                tasks.push(t);
+            }
+            }
+            monitor.wait(tasks.top()->sortTime);
+        }
+    }
+}
+
+void Timer::add(intrusive_ptr<TimerTask> task)
+{
+    Monitor::ScopedLock l(monitor);
+    task->sortTime = task->nextFireTime;
+    tasks.push(task);
+    monitor.notify();
+}
+
+void Timer::start()
+{
+    Monitor::ScopedLock l(monitor);
+    if (!active) {
+        active = true;
+        runner = Thread(this);
+    }
+}
+
+void Timer::stop()
+{
+    {
+        Monitor::ScopedLock l(monitor);
+        if (!active) return;
+        active = false;
+        monitor.notifyAll();
+    }
+    runner.join();
+}
+
+bool operator<(const intrusive_ptr<TimerTask>& a,
+                       const intrusive_ptr<TimerTask>& b)
+{
+    // Lower priority if time is later
+    return a.get() && b.get() && a->sortTime > b->sortTime;
+}
+
+}}