1 files changed, 140 insertions, 0 deletions
diff --git a/qpid/cpp/src/qpid/ha/QueueGuard.cpp b/qpid/cpp/src/qpid/ha/QueueGuard.cpp
new file mode 100644
index 0000000000..1f4ff4e48b
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+++ b/qpid/cpp/src/qpid/ha/QueueGuard.cpp
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+/*
+ *
+ * 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 "QueueGuard.h"
+#include "ReplicatingSubscription.h"
+#include "qpid/broker/Queue.h"
+#include "qpid/broker/QueuedMessage.h"
+#include "qpid/broker/QueueObserver.h"
+#include "qpid/log/Statement.h"
+#include <boost/bind.hpp>
+#include <sstream>
+
+namespace qpid {
+namespace ha {
+
+using namespace broker;
+using sys::Mutex;
+using framing::SequenceNumber;
+using framing::SequenceSet;
+
+class QueueGuard::QueueObserver : public broker::QueueObserver
+{
+  public:
+    QueueObserver(QueueGuard& g) : guard(g) {}
+    void enqueued(const broker::QueuedMessage& qm) { guard.enqueued(qm); }
+    void dequeued(const broker::QueuedMessage& qm) { guard.dequeued(qm); }
+    void acquired(const broker::QueuedMessage&) {}
+    void requeued(const broker::QueuedMessage&) {}
+  private:
+    QueueGuard& guard;
+};
+
+
+
+QueueGuard::QueueGuard(broker::Queue& q, const BrokerInfo& info)
+    : queue(q), subscription(0), range(q)
+{
+    // NOTE: The QueueGuard is created before the queue becomes active: either
+    // when a backup is promoted, or when a new queue is created on the primary.
+    std::ostringstream os;
+    os << "Primary guard " << queue.getName() << "@" << info.getLogId() << ": ";
+    logPrefix = os.str();
+    observer.reset(new QueueObserver(*this));
+    queue.addObserver(observer);
+}
+
+QueueGuard::~QueueGuard() { cancel(); }
+
+// NOTE: Called with message lock held.
+void QueueGuard::enqueued(const QueuedMessage& qm) {
+    assert(qm.queue == &queue);
+    // Delay completion
+    QPID_LOG(trace, logPrefix << "Delayed completion of " << qm);
+    qm.payload->getIngressCompletion().startCompleter();
+    {
+        Mutex::ScopedLock l(lock);
+        assert(!delayed.contains(qm.position));
+        delayed += qm.position;
+    }
+}
+
+// NOTE: Called with message lock held.
+void QueueGuard::dequeued(const QueuedMessage& qm) {
+    assert(qm.queue == &queue);
+    QPID_LOG(trace, logPrefix << "Dequeued " << qm);
+    ReplicatingSubscription* rs=0;
+    {
+        Mutex::ScopedLock l(lock);
+        rs = subscription;
+    }
+    if (rs) rs->dequeued(qm);
+    complete(qm);
+}
+
+void QueueGuard::cancel() {
+    queue.removeObserver(observer);
+    {
+        Mutex::ScopedLock l(lock);
+        if (delayed.empty()) return; // No need if no delayed messages.
+    }
+    // FIXME aconway 2012-06-15: optimize, only messages in delayed set.
+    queue.eachMessage(boost::bind(&QueueGuard::complete, this, _1));
+}
+
+void QueueGuard::attach(ReplicatingSubscription& rs) {
+    Mutex::ScopedLock l(lock);
+     subscription = &rs;
+}
+
+namespace {
+void completeBefore(QueueGuard* guard, SequenceNumber position, const QueuedMessage& qm) {
+    if (qm.position <= position) guard->complete(qm);
+}
+}
+
+bool QueueGuard::subscriptionStart(SequenceNumber position) {
+   // Complete any messages before or at the ReplicatingSubscription start position.
+    if (!delayed.empty() && delayed.front() <= position) {
+        // FIXME aconway 2012-06-15: queue iteration, only messages in delayed
+        queue.eachMessage(boost::bind(&completeBefore, this, position, _1));
+    }
+    return position >= range.back;
+}
+
+void QueueGuard::complete(const QueuedMessage& qm) {
+    assert(qm.queue == &queue);
+    {
+        Mutex::ScopedLock l(lock);
+        // The same message can be completed twice, by
+        // ReplicatingSubscription::acknowledged and dequeued. Remove it
+        // from the set so we only call finishCompleter() once
+        if (delayed.contains(qm.position))
+            delayed -= qm.position;
+        else
+            return;
+    }
+    QPID_LOG(trace, logPrefix << "Completed " << qm);
+    qm.payload->getIngressCompletion().finishCompleter();
+}
+
+// FIXME aconway 2012-06-04: TODO support for timeout.
+
+}} // namespaces qpid::ha