Simplify SessionState, preparing for session thread safety fixes.

git-svn-id: https://svn.apache.org/repos/asf/incubator/qpid/trunk@590751 13f79535-47bb-0310-9956-ffa450edef68

7 files changed, 15 insertions, 53 deletions

diff --git a/qpid/cpp/src/qpid/broker/SessionHandler.cpp b/qpid/cpp/src/qpid/broker/SessionHandler.cpp
index 49492ffed1..1d0e67f6ab 100644
--- a/qpid/cpp/src/qpid/broker/SessionHandler.cpp
+++ b/qpid/cpp/src/qpid/broker/SessionHandler.cpp
@@ -38,7 +38,8 @@ SessionHandler::SessionHandler(Connection& c, ChannelId ch)
       connection(c), channel(ch, &c.getOutput()),
       proxy(out),               // Via my own handleOut() for L2 data.
       peerSession(channel),     // Direct to channel for L2 commands.
-      ignoring(false) {}
+      ignoring(false),
+      resuming(false) {}
 
 SessionHandler::~SessionHandler() {}
 
@@ -114,7 +115,8 @@ void  SessionHandler::resume(const Uuid& id) {
     assertClosed("resume");
     session = connection.broker.getSessionManager().resume(id);
     session->attach(*this);
-    SequenceNumber seq = session->resuming();
+    resuming=true;
+    SequenceNumber seq = session->sendingAck();
     peerSession.attached(session->getId(), session->getTimeout());
     proxy.getSession().ack(seq, SequenceNumberSet());
 }
@@ -148,7 +150,7 @@ void  SessionHandler::closed(uint16_t replyCode, const string& replyText) {
 }
 
 void SessionHandler::localSuspend() {
-    if (session.get() && session->getState() == SessionState::ATTACHED) {
+    if (session.get()) {
         session->detach();
         connection.broker.getSessionManager().suspend(session);
     }
@@ -166,7 +168,8 @@ void  SessionHandler::ack(uint32_t     cumulativeSeenMark,
                           const SequenceNumberSet& /*seenFrameSet*/)
 {
     assertAttached("ack");
-    if (session->getState() == SessionState::RESUMING) {
+    if (resuming) {
+        resuming=false;
         session->receivedAck(cumulativeSeenMark);
         framing::SessionState::Replay replay=session->replay();
         std::for_each(replay.begin(), replay.end(),
diff --git a/qpid/cpp/src/qpid/broker/SessionHandler.h b/qpid/cpp/src/qpid/broker/SessionHandler.h
index 9a68ddb46f..52f64779d4 100644
--- a/qpid/cpp/src/qpid/broker/SessionHandler.h
+++ b/qpid/cpp/src/qpid/broker/SessionHandler.h
@@ -92,6 +92,7 @@ class SessionHandler : public framing::FrameHandler::InOutHandler,
     framing::AMQP_ClientProxy proxy;
     framing::AMQP_ClientProxy::Session peerSession;
     bool ignoring;
+    bool resuming;
     std::auto_ptr<SessionState> session;
 };
 
diff --git a/qpid/cpp/src/qpid/broker/SessionManager.cpp b/qpid/cpp/src/qpid/broker/SessionManager.cpp
index f12ebc6db1..5bdc572491 100644
--- a/qpid/cpp/src/qpid/broker/SessionManager.cpp
+++ b/qpid/cpp/src/qpid/broker/SessionManager.cpp
@@ -56,7 +56,6 @@ std::auto_ptr<SessionState>  SessionManager::open(
 void  SessionManager::suspend(std::auto_ptr<SessionState> session) {
     Mutex::ScopedLock l(lock);
     active.erase(session->getId());
-    session->suspend();
     session->expiry = AbsTime(now(),session->getTimeout()*TIME_SEC);
     suspended.push_back(session.release()); // In expiry order
     eraseExpired();
diff --git a/qpid/cpp/src/qpid/client/SessionCore.cpp b/qpid/cpp/src/qpid/client/SessionCore.cpp
index f7f0f52dba..30df574716 100644
--- a/qpid/cpp/src/qpid/client/SessionCore.cpp
+++ b/qpid/cpp/src/qpid/client/SessionCore.cpp
@@ -52,7 +52,6 @@ inline void SessionCore::invariant() const {
         break;
       case RESUMING:
         assert(session);
-        assert(session->getState() == SessionState::RESUMING);
         assert(code==REPLY_SUCCESS);
         assert(connection);
         assert(channel.get());
@@ -143,7 +142,6 @@ void SessionCore::doSuspend(int code, const std::string& text) {
     if (state != CLOSED) {
         invariant();
         detach(code, text);
-        session->suspend();
         setState(SUSPENDED);
     }
 }
@@ -202,7 +200,7 @@ void SessionCore::resume(shared_ptr<ConnectionImpl> c) {
         if (state==OPEN)
             doSuspend(REPLY_SUCCESS, OK);
         check(state==SUSPENDED, COMMAND_INVALID, QPID_MSG("Session cannot be resumed."));
-        SequenceNumber sendAck=session->resuming();
+        SequenceNumber sendAck=session->sendingAck();
         attaching(c);
         proxy.resume(getId());
         waitFor(OPEN);
diff --git a/qpid/cpp/src/qpid/framing/SessionState.cpp b/qpid/cpp/src/qpid/framing/SessionState.cpp
index 8056f4a523..7e905bdf63 100644
--- a/qpid/cpp/src/qpid/framing/SessionState.cpp
+++ b/qpid/cpp/src/qpid/framing/SessionState.cpp
@@ -33,7 +33,6 @@ namespace qpid {
 namespace framing {
 
 SessionState::SessionState(uint32_t ack,  const Uuid& uuid) :
-    state(ATTACHED),
     id(uuid),
     lastReceived(-1),
     lastSent(-1),
@@ -45,7 +44,6 @@ SessionState::SessionState(uint32_t ack,  const Uuid& uuid) :
 {}
 
 SessionState::SessionState(const Uuid& uuid) :
-    state(ATTACHED),
     id(uuid),
     lastReceived(-1),
     lastSent(-1),
@@ -65,10 +63,6 @@ bool isSessionCommand(const AMQFrame& f) {
 boost::optional<SequenceNumber> SessionState::received(const AMQFrame& f) {
     if (isSessionCommand(f))
         return boost::none;
-    if (state==RESUMING)
-        throw CommandInvalidException(
-            QPID_MSG("Invalid frame: Resuming session, expected session-ack"));
-    assert(state = ATTACHED);
     ++lastReceived;
     QPID_LOG(trace, "Recv # "<< lastReceived << " " << id);
     if (ackInterval && lastReceived == sendAckAt)
@@ -85,7 +79,6 @@ bool SessionState::sent(const AMQFrame& f) {
     ++lastSent;
     QPID_LOG(trace, "Sent # "<< lastSent << " " << id);
     return ackInterval &&
-        (state!=RESUMING) &&
         (lastSent == solicitAckAt) &&
         sendingSolicit();
 }
@@ -97,8 +90,6 @@ SessionState::Replay SessionState::replay() {
 }
 
 void SessionState::receivedAck(SequenceNumber acked) {
-    if (state==RESUMING) state=ATTACHED;
-    assert(state==ATTACHED);
      if (lastSent < acked)
         throw InvalidArgumentException("Invalid sequence number in ack");
     size_t keep = lastSent - acked;
@@ -113,22 +104,10 @@ SequenceNumber SessionState::sendingAck() {
 }
 
 bool SessionState::sendingSolicit() {
-    assert(state == ATTACHED);
     if (ackSolicited)
         return false;
     solicitAckAt = lastSent + ackInterval;
     return ackInterval != 0;
 }
 
-SequenceNumber SessionState::resuming() {
-    if (!resumable)
-        throw InternalErrorException("Session is not resumable");
-    state = RESUMING;
-    return sendingAck();
-}
-
-void SessionState::suspend() {
-    state = SUSPENDED;
-}
-
 }} // namespace qpid::framing
diff --git a/qpid/cpp/src/qpid/framing/SessionState.h b/qpid/cpp/src/qpid/framing/SessionState.h
index 361c960db1..5034de4e94 100644
--- a/qpid/cpp/src/qpid/framing/SessionState.h
+++ b/qpid/cpp/src/qpid/framing/SessionState.h
@@ -35,7 +35,10 @@ namespace framing {
 
 /**
  * Session state common to client and broker.
- * Stores replay frames, implements session ack/resume protcools.
+ * 
+ * Stores data needed to resume a session: replay frames, implements
+ * session ack/resume protcools. Stores handler chains for the session,
+ * handlers may themselves store state.
  *
  * A SessionState is always associated with an _open_ session (attached or
  * suspended) it is destroyed when the session is closed.
@@ -46,13 +49,6 @@ 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
@@ -60,7 +56,8 @@ class SessionState
      * 
      * N=0 disables voluntary send/solict ack.
      */
-    SessionState(uint32_t ackInterval, const framing::Uuid& id=framing::Uuid(true));
+    SessionState(uint32_t ackInterval,
+                 const framing::Uuid& id=framing::Uuid(true));
 
     /**
      * Create a non-resumable session. Does not store session frames,
@@ -69,7 +66,6 @@ class SessionState
     SessionState(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.
@@ -92,13 +88,6 @@ class SessionState
      */
     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
@@ -115,9 +104,7 @@ class SessionState
 
     bool sendingSolicit();
 
-    State state;
     framing::Uuid id;
-
     Unacked unackedOut;
     SequenceNumber lastReceived;
     SequenceNumber lastSent;
diff --git a/qpid/cpp/src/tests/SessionState.cpp b/qpid/cpp/src/tests/SessionState.cpp
index c8d912801e..19a146c759 100644
--- a/qpid/cpp/src/tests/SessionState.cpp
+++ b/qpid/cpp/src/tests/SessionState.cpp
@@ -97,21 +97,16 @@ BOOST_AUTO_TEST_CASE(testReplay) {
     // Replay of all frames.
     SessionState session(100);
     sent(session, "abc"); 
-    session.suspend(); session.resuming();
     session.receivedAck(-1);
     BOOST_CHECK_EQUAL(replayChars(session.replay()), "abc");
 
     // Replay with acks
     session.receivedAck(0); // ack a.
-    session.suspend();
-    session.resuming();
     session.receivedAck(1); // ack b.
     BOOST_CHECK_EQUAL(replayChars(session.replay()), "c");
 
     // Replay after further frames.
     sent(session, "def");
-    session.suspend();
-    session.resuming();
     session.receivedAck(3);
     BOOST_CHECK_EQUAL(replayChars(session.replay()), "ef");