From f61e1ef7589da893b9b54448224dc0961515eb40 Mon Sep 17 00:00:00 2001
From: Alan Conway <aconway@apache.org>
Date: Fri, 26 Oct 2007 19:48:31 +0000
Subject: Session resume support in client & broker: Client can resume a
 session after voluntary suspend() or network failure. Frames lost in network
 failure are automatically re-transmitted for transparent re-connection.

client::Session improvements:
 - Locking to avoid races between network & user threads.
 - Replaced client::StateManager with sys::StateMonitor - avoid heap allocation.

qpid::Exception clean up:
 - use QPID_MSG consistently to format exception messages.
 - throw typed exceptions (in reply_exceptions.h) for AMQP exceptions.
 - re-throw correct typed exception on client for exceptions from broker.
 - Removed QpidError.h

rubygen/templates/constants.rb:
 - constants.h: Added FOO_CLASS_ID and FOO_BAR_METHOD_ID constants.
 - reply_constants.h: Added throwReplyException(code, text)

log::Logger:
 - Fixed shutdown race in Statement::~Initializer()


git-svn-id: https://svn.apache.org/repos/asf/incubator/qpid/trunk/qpid@588761 13f79535-47bb-0310-9956-ffa450edef68
---
 cpp/src/qpid/framing/SessionState.h | 127 ++++++++++++++++++++++++++++++++++++
 1 file changed, 127 insertions(+)
 create mode 100644 cpp/src/qpid/framing/SessionState.h

(limited to 'cpp/src/qpid/framing/SessionState.h')

diff --git a/cpp/src/qpid/framing/SessionState.h b/cpp/src/qpid/framing/SessionState.h
new file mode 100644
index 0000000000..66fc083d3f
--- /dev/null
+++ b/cpp/src/qpid/framing/SessionState.h
@@ -0,0 +1,127 @@
+#ifndef QPID_FRAMING_SESSIONSTATE_H
+#define QPID_FRAMING_SESSIONSTATE_H
+
+/*
+ *
+ * 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/framing/SequenceNumber.h"
+#include "qpid/framing/Uuid.h"
+#include "qpid/framing/AMQFrame.h"
+
+#include <boost/optional.hpp>
+
+#include <deque>
+
+namespace qpid {
+namespace framing {
+
+/**
+ * Session state common to client and broker.
+ * Implements session ack/resume protcools.
+ *
+ * A SessionState is always associated with an _open_ session (attached or
+ * suspended) it is destroyed when the session is closed.
+ *
+ * A template to make it protocol independent and easy to test.
+ */
+class SessionState
+{
+  public:
+    typedef std::vector<AMQFrame> Replay;
+
+    /** States of a session. */
+    enum State {
+        SUSPENDED, ///< Suspended, detached from any channel.
+        RESUMING, ///< Resuming: waiting for initial ack from peer.
+        ATTACHED ///< Attached to channel and operating normally.
+    };
+
+    /**
+     *Create a newly opened active session.
+     *@param ackInterval send/solicit an ack whenever N unacked frames
+     * have been received/sent.
+     *@pre ackInterval > 0
+     */
+    SessionState(uint32_t ackInterval=1, const framing::Uuid& id=framing::Uuid(true));
+
+    const framing::Uuid& getId() const { return id; }
+    State getState() const { return state; }
+    
+    /** Received incoming L3 frame.
+     * @return SequenceNumber if an ack should be sent, empty otherwise.
+     * SessionState assumes that acks are sent whenever it returns
+     * a seq. number.
+     */
+    boost::optional<SequenceNumber> received(const AMQFrame&);
+
+    /** Sent outgoing L3 frame.
+     *@return true if solicit-ack should be sent. Note the SessionState
+     *assumes that a solicit-ack is sent every time it returns true.
+     */
+    bool sent(const AMQFrame&);
+
+    /** Received normal incoming ack. */
+    void receivedAck(SequenceNumber);
+
+    /** Frames to replay 
+     *@pre getState()==ATTACHED
+     */
+    Replay replay();
+
+    /** Suspend the session. */
+    void suspend();
+
+    /** Start resume protocol for the session.
+     *@returns sequence number to ack immediately.  */
+    SequenceNumber resuming();
+
+    /** About to send an unscheduled ack, e.g. to respond to a solicit-ack.
+     * 
+     * Note: when received() returns a sequence number this function
+     * should not be called. SessionState assumes that the ack is sent
+     * every time received() returns a sequence number.
+     */
+    SequenceNumber sendingAck();
+
+    SequenceNumber getLastSent() const { return lastSent; }
+    SequenceNumber getLastReceived() const { return lastReceived; }
+  private:
+    typedef std::deque<AMQFrame> Unacked;
+
+    bool sendingSolicit();
+
+    State state;
+    framing::Uuid id;
+    Unacked unackedOut;
+    SequenceNumber lastReceived;
+    SequenceNumber lastSent;
+    uint32_t ackInterval;
+    SequenceNumber sendAckAt;
+    SequenceNumber solicitAckAt;
+    bool ackSolicited;
+    bool suspending;
+};
+
+
+}} // namespace qpid::common
+
+
+#endif  /*!QPID_FRAMING_SESSIONSTATE_H*/
-- 
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