1 files changed, 89 insertions, 0 deletions
diff --git a/qpid/cpp/src/qpid/sys/AggregateOutput.cpp b/qpid/cpp/src/qpid/sys/AggregateOutput.cpp
new file mode 100644
index 0000000000..773ea68e55
--- /dev/null
+++ b/qpid/cpp/src/qpid/sys/AggregateOutput.cpp
@@ -0,0 +1,89 @@
+/*
+ *
+ * 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/AggregateOutput.h"
+#include "qpid/log/Statement.h"
+#include <algorithm>
+
+namespace qpid {
+namespace sys {
+
+AggregateOutput::AggregateOutput() : busy(false) {}
+
+namespace {
+// Clear the busy flag and notify waiting threads in destructor.
+struct ScopedBusy {
+    bool& flag;
+    Monitor& monitor;
+    ScopedBusy(bool& f, Monitor& m) : flag(f), monitor(m) { f = true; }
+    ~ScopedBusy() { flag = false; monitor.notifyAll(); }
+};
+}
+
+bool AggregateOutput::doOutput() {
+    Mutex::ScopedLock l(lock);
+    ScopedBusy sb(busy, lock);
+
+    while (!tasks.empty()) {
+        OutputTask* t=tasks.front();
+        tasks.pop_front();
+        taskSet.erase(t);
+        bool didOutput;
+        {
+            // Allow concurrent call to addOutputTask.
+            // removeOutputTask will wait till !busy before removing a task.
+            Mutex::ScopedUnlock u(lock);
+            didOutput = t->doOutput();
+        }
+        if (didOutput) {
+            if (taskSet.insert(t).second) {
+                tasks.push_back(t);
+            }
+            return true;
+        }
+    }
+    return false;
+}
+  
+void AggregateOutput::addOutputTask(OutputTask* task) {
+    Mutex::ScopedLock l(lock);
+    if (taskSet.insert(task).second) {
+        tasks.push_back(task);
+    }
+}
+
+void AggregateOutput::removeOutputTask(OutputTask* task) {
+    Mutex::ScopedLock l(lock);
+    while (busy) lock.wait();
+    taskSet.erase(task);
+    tasks.erase(std::remove(tasks.begin(), tasks.end(), task), tasks.end());
+}
+  
+void AggregateOutput::removeAll()
+{
+    Mutex::ScopedLock l(lock);
+    while (busy) lock.wait();
+    taskSet.clear();
+    tasks.clear();
+}
+  
+
+}} // namespace qpid::sys