QPID-3603: Introduced RemoteBackup to track backup status.

The primary creates RemoteBackup object for each connected or expected
backup. On first being promoted, the new primary has a RemoteBackup
for each of the known backups at the time of the failure.

The RemoteBackup manages queue guards for its backup and
tracks it's readiness.

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk/qpid@1349540 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 30 insertions, 6 deletions

diff --git a/cpp/src/qpid/ha/QueueGuard.cpp b/cpp/src/qpid/ha/QueueGuard.cpp
index 55dc6b0d50..5ea4c8e6f8 100644
--- a/cpp/src/qpid/ha/QueueGuard.cpp
+++ b/cpp/src/qpid/ha/QueueGuard.cpp
@@ -22,6 +22,7 @@
 #include "ReplicatingSubscription.h"
 #include "qpid/broker/Queue.h"
 #include "qpid/broker/QueuedMessage.h"
+#include "qpid/broker/QueueObserver.h"
 #include "qpid/log/Statement.h"
 #include <sstream>
 
@@ -31,19 +32,33 @@ namespace ha {
 using namespace broker;
 using sys::Mutex;
 
+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)
 {
     // Set a log prefix message that identifies the remote broker.
     std::ostringstream os;
-    os << "HA subscription " << queue.getName() << "@" << info.getLogId() << ": ";
+    os << "HA guard " << queue.getName() << "@" << info.getLogId() << ": ";
     logPrefix = os.str();
+    observer.reset(new QueueObserver(*this));
+    queue.addObserver(observer);
+    readyPosition = queue.getPosition(); // Must set after addObserver()
 }
 
-void QueueGuard::initialize() {
-    Mutex::ScopedLock l(lock);
-    queue.addObserver(shared_from_this());
-}
+QueueGuard::~QueueGuard() { cancel(); }
 
 void QueueGuard::enqueued(const QueuedMessage& qm) {
     // Delay completion
@@ -69,7 +84,11 @@ void QueueGuard::dequeued(const QueuedMessage& qm) {
 }
 
 void QueueGuard::cancel() {
-    queue.removeObserver(shared_from_this());
+    queue.removeObserver(observer);
+    {
+        sys::Mutex::ScopedLock l(lock);
+        if (delayed.empty()) return; // No need if no delayed messages.
+    }
     queue.eachMessage(boost::bind(&QueueGuard::complete, this, _1));
 }
 
@@ -94,6 +113,11 @@ void QueueGuard::complete(const QueuedMessage& qm) {
     complete(qm, l);
 }
 
+framing::SequenceNumber QueueGuard::getReadyPosition() {
+    // No lock, readyPosition is immutable.
+    return readyPosition;
+}
+
 // FIXME aconway 2012-06-04: TODO support for timeout.
 
 }} // namespaces qpid::ha