cpp/src/qpid/client/SessionImpl.cpp

/*
 *
 * 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/client/SessionImpl.h"

#include "qpid/client/ConnectionImpl.h"
#include "qpid/client/Future.h"

#include "qpid/framing/all_method_bodies.h"
#include "qpid/framing/ClientInvoker.h"
#include "qpid/framing/enum.h"
#include "qpid/framing/FrameSet.h"
#include "qpid/framing/AMQFrame.h"
#include "qpid/framing/MethodContent.h"
#include "qpid/framing/SequenceSet.h"
#include "qpid/framing/reply_exceptions.h"
#include "qpid/framing/DeliveryProperties.h"
#include "qpid/log/Statement.h"
#include "qpid/sys/IntegerTypes.h"

#include <boost/bind.hpp>
#include <boost/shared_ptr.hpp>

namespace { const std::string EMPTY; }

namespace qpid {
namespace client {

using namespace qpid::framing;
using namespace qpid::framing::session; //for detach codes

typedef sys::Monitor::ScopedLock  Lock;
typedef sys::Monitor::ScopedUnlock  UnLock;
typedef sys::ScopedLock<sys::Semaphore>  Acquire;


SessionImpl::SessionImpl(const std::string& name, boost::shared_ptr<ConnectionImpl> conn)
    : state(INACTIVE),
      detachedLifetime(0),
      maxFrameSize(conn->getNegotiatedSettings().maxFrameSize),
      id(conn->getNegotiatedSettings().username, name.empty() ? Uuid(true).str() : name),
      connection(conn),
      ioHandler(*this),
      proxy(ioHandler),
      nextIn(0),
      nextOut(0)
{
    channel.next = connection.get();
}

SessionImpl::~SessionImpl() {
    {
        Lock l(state);
        if (state != DETACHED && state != DETACHING) {
            QPID_LOG(warning, "Session was not closed cleanly: " << id);
            // Inform broker but don't wait for detached as that deadlocks.
            // The detached will be ignored as the channel will be invalid.
            try { detach(); } catch (...) {}    // ignore errors.
            setState(DETACHED);
            handleClosed();
            state.waitWaiters();
        }
    }
    connection->erase(channel);
}


FrameSet::shared_ptr SessionImpl::get() // user thread
{
    // No lock here: pop does a blocking wait.
    return demux.getDefault()->pop();
}

const SessionId SessionImpl::getId() const //user thread
{
    return id; //id is immutable
}

void SessionImpl::open(uint32_t timeout) // user thread
{
    Lock l(state);
    if (state == INACTIVE) {
        setState(ATTACHING);
        proxy.attach(id.getName(), false);
        waitFor(ATTACHED);
        //TODO: timeout will not be set locally until get response to
        //confirm, should we wait for that?
        setTimeout(timeout);
        proxy.commandPoint(nextOut, 0);
    } else {
        throw Exception("Open already called for this session");
    }
}

void SessionImpl::close() //user thread
{
    Lock l(state);
    // close() must be idempotent and no-throw as it will often be called in destructors.
    if (state != DETACHED && state != DETACHING) {
        try {
            if (detachedLifetime) setTimeout(0);
            detach();
            waitFor(DETACHED);
        } catch (...) {}
        setState(DETACHED);
    }
}

void SessionImpl::resume(boost::shared_ptr<ConnectionImpl>) // user thread
{
    throw NotImplementedException("Resume not yet implemented by client!");
}

void SessionImpl::suspend() //user thread
{
    Lock l(state);
    detach();
}

void SessionImpl::detach() //call with lock held
{
    if (state == ATTACHED) {
        setState(DETACHING);
        proxy.detach(id.getName());
    }
}


uint16_t SessionImpl::getChannel() const // user thread
{
    return channel;
}

void SessionImpl::setChannel(uint16_t c) // user thread
{
    //channel will only ever be set when session is detached (and
    //about to be resumed)
    channel = c;
}

Demux& SessionImpl::getDemux()
{
    return demux;
}

void SessionImpl::waitForCompletion(const SequenceNumber& id)
{
    Lock l(state);
    sys::Waitable::ScopedWait w(state);
    waitForCompletionImpl(id);
}

void SessionImpl::waitForCompletionImpl(const SequenceNumber& id) //call with lock held
{
    while (incompleteOut.contains(id)) {
        checkOpen();
        state.wait();
    }
}

bool SessionImpl::isComplete(const SequenceNumber& id)
{
    Lock l(state);
    return !incompleteOut.contains(id);
}

struct IsCompleteUpTo
{
    const SequenceNumber& id;
    bool result;

    IsCompleteUpTo(const SequenceNumber& _id) : id(_id), result(true) {}
    void operator()(const SequenceNumber& start, const SequenceNumber&)
    {
        if (start <= id) result = false;
    }

};

bool SessionImpl::isCompleteUpTo(const SequenceNumber& id)
{
    Lock l(state);
    //return false if incompleteOut contains anything less than id,
    //true otherwise
    IsCompleteUpTo f(id);
    incompleteIn.for_each(f);
    return f.result;
}

framing::SequenceNumber SessionImpl::getCompleteUpTo()
{
    SequenceNumber firstIncomplete;
    {
        Lock l(state);
        firstIncomplete = incompleteIn.front();
    }
    return --firstIncomplete;
}

struct MarkCompleted
{
    const SequenceNumber& id;
    SequenceSet& completedIn;

    MarkCompleted(const SequenceNumber& _id, SequenceSet& set) : id(_id), completedIn(set) {}

    void operator()(const SequenceNumber& start, const SequenceNumber& end)
    {
        if (id >= end) {
            completedIn.add(start, end);
        } else if (id >= start) {
            completedIn.add(start, id);
        }
    }

};

void SessionImpl::markCompleted(const SequenceSet& ids, bool notifyPeer)
{
    Lock l(state);
    incompleteIn.remove(ids);
    completedIn.add(ids);
    if (notifyPeer) {
        sendCompletion();
    }
}

void SessionImpl::markCompleted(const SequenceNumber& id, bool cumulative, bool notifyPeer)
{
    Lock l(state);
    if (cumulative) {
        //everything in incompleteIn less than or equal to id is now complete
        MarkCompleted f(id, completedIn);
        incompleteIn.for_each(f);
        //make sure id itself is in
        completedIn.add(id);
        //then remove anything thats completed from the incomplete set
        incompleteIn.remove(completedIn);
    } else if (incompleteIn.contains(id)) {
        incompleteIn.remove(id);
        completedIn.add(id);
    }
    if (notifyPeer) {
        sendCompletion();
    }
}

void SessionImpl::setException(const sys::ExceptionHolder& ex) {
    Lock l(state);
    setExceptionLH(ex);
}

void SessionImpl::setExceptionLH(const sys::ExceptionHolder& ex) { // Call with lock held.
    exceptionHolder = ex;
    setState(DETACHED);
}

/**
 * Called by ConnectionImpl to notify active sessions when connection
 * is explictly closed
 */
void SessionImpl::connectionClosed(uint16_t code, const std::string& text)  {
    setException(createConnectionException(code, text));
    handleClosed();
}

/**
 * Called by ConnectionImpl to notify active sessions when connection
 * is disconnected
 */
void SessionImpl::connectionBroke(const std::string& _text) {
    setException(sys::ExceptionHolder(new TransportFailure(_text)));
    handleClosed();
}

Future SessionImpl::send(const AMQBody& command)
{
    return sendCommand(command);
}

Future SessionImpl::send(const AMQBody& command, const MethodContent& content)
{
    return sendCommand(command, &content);
}

namespace {
// Functor for FrameSet::map to send header + content frames but, not method frames.
struct SendContentFn {
    FrameHandler& handler;
    void operator()(const AMQFrame& f) {
        if (!f.getMethod())
            handler(const_cast<AMQFrame&>(f));
    }
    SendContentFn(FrameHandler& h) : handler(h) {}
};

}

Future SessionImpl::send(const AMQBody& command, const FrameSet& content) {
    Acquire a(sendLock);
    SequenceNumber id = nextOut++;
    {
        Lock l(state);
        checkOpen();
        incompleteOut.add(id);
    }
    Future f(id);
    if (command.getMethod()->resultExpected()) {
        Lock l(state);
        //result listener must be set before the command is sent
        f.setFutureResult(results.listenForResult(id));
    }
    AMQFrame frame(command);
    frame.setEof(false);
    handleOut(frame);
    SendContentFn send(out);
    content.map(send);
    return f;
}

void SessionImpl::sendRawFrame(AMQFrame& frame) {
    Acquire a(sendLock);
    handleOut(frame);
}

Future SessionImpl::sendCommand(const AMQBody& command, const MethodContent* content)
{
    Acquire a(sendLock);
    SequenceNumber id = nextOut++;
    {
        Lock l(state);
        checkOpen();
        incompleteOut.add(id);
    }
    Future f(id);
    if (command.getMethod()->resultExpected()) {
        Lock l(state);
        //result listener must be set before the command is sent
        f.setFutureResult(results.listenForResult(id));
    }
    AMQFrame frame(command);
    if (content) {
        frame.setEof(false);
    }
    handleOut(frame);
    if (content) {
        sendContent(*content);
    }
    return f;
}

void SessionImpl::sendContent(const MethodContent& content)
{
    AMQFrame header(content.getHeader());

    header.setFirstSegment(false);
    uint64_t data_length = content.getData().length();
    if(data_length > 0){
        header.setLastSegment(false);
        handleOut(header);
        /*Note: end of frame marker included in overhead but not in size*/
        const uint32_t frag_size = maxFrameSize - AMQFrame::frameOverhead();

        if(data_length < frag_size){
            AMQFrame frame((AMQContentBody(content.getData())));
            frame.setFirstSegment(false);
            handleOut(frame);
        }else{
            uint32_t offset = 0;
            uint32_t remaining = data_length - offset;
            while (remaining > 0) {
                uint32_t length = remaining > frag_size ? frag_size : remaining;
                std::string frag(content.getData().substr(offset, length));
                AMQFrame frame((AMQContentBody(frag)));
                frame.setFirstSegment(false);
                frame.setLastSegment(true);
                if (offset > 0) {
                    frame.setFirstFrame(false);
                }
                offset += length;
                remaining = data_length - offset;
                if (remaining) {
                    frame.setLastFrame(false);
                }
                handleOut(frame);
            }
        }
    } else {
        handleOut(header);
    }
}


bool isMessageMethod(AMQMethodBody* method)
{
    return method->isA<MessageTransferBody>();
}

bool isMessageMethod(AMQBody* body)
{
    AMQMethodBody* method=body->getMethod();
    return method && isMessageMethod(method);
}

bool isContentFrame(AMQFrame& frame)
{
    AMQBody* body = frame.getBody();
    uint8_t type = body->type();
    return type == HEADER_BODY || type == CONTENT_BODY || isMessageMethod(body);
}

void SessionImpl::handleIn(AMQFrame& frame) // network thread
{
    try {
        if (invoke(static_cast<SessionHandler&>(*this), *frame.getBody())) {
            ;
        } else if (invoke(static_cast<ExecutionHandler&>(*this), *frame.getBody())) {
            //make sure the command id sequence and completion
            //tracking takes account of execution commands
            Lock l(state);
            completedIn.add(nextIn++);
        } else {
            //if not handled by this class, its for the application:
            deliver(frame);
        }
    }
    catch (const SessionException& e) {
        setException(createSessionException(e.code, e.getMessage()));
    }
    catch (const ChannelException& e) {
        setException(createChannelException(e.code, e.getMessage()));
    }
}

void SessionImpl::handleOut(AMQFrame& frame) // user thread
{
    sendFrame(frame, true);
}

void SessionImpl::proxyOut(AMQFrame& frame) // network thread
{
    //Note: this case is treated slightly differently that command
    //frames sent by application; session controls should not be
    //blocked by bounds checking on the outgoing frame queue.
    sendFrame(frame, false);
}

void SessionImpl::sendFrame(AMQFrame& frame, bool canBlock)
{
    connection->expand(frame.encodedSize(), canBlock);
    channel.handle(frame);
}

void SessionImpl::deliver(AMQFrame& frame) // network thread
{
    if (!arriving) {
        arriving = FrameSet::shared_ptr(new FrameSet(nextIn++));
    }
    arriving->append(frame);
    if (arriving->isComplete()) {
        //message.transfers will be marked completed only when 'acked'
        //as completion affects flow control; other commands will be
        //considered completed as soon as processed here
        if (arriving->isA<MessageTransferBody>()) {
            Lock l(state);
            incompleteIn.add(arriving->getId());
        } else {
            Lock l(state);
            completedIn.add(arriving->getId());
        }
        demux.handle(arriving);
        arriving.reset();
    }
}

//control handler methods (called by network thread when controls are
//received from peer):

void SessionImpl::attach(const std::string& /*name*/, bool /*force*/)
{
    throw NotImplementedException("Client does not support attach");
}

void SessionImpl::attached(const std::string& _name)
{
    Lock l(state);
    if (id.getName() != _name) throw InternalErrorException("Incorrect session name");
    setState(ATTACHED);
}

void SessionImpl::detach(const std::string& _name)
{
    Lock l(state);
    if (id.getName() != _name) throw InternalErrorException("Incorrect session name");
    setState(DETACHED);
    QPID_LOG(info, "Session detached by peer: " << id);
    proxy.detached(_name, DETACH_CODE_NORMAL);
    handleClosed();
}

void SessionImpl::detached(const std::string& _name, uint8_t _code) {
    Lock l(state);
    if (id.getName() != _name) throw InternalErrorException("Incorrect session name");
    setState(DETACHED);
    if (_code) {
        //TODO: make sure this works with execution.exception - don't
        //want to overwrite the code from that
        setExceptionLH(createChannelException(_code, "Session detached by peer"));
        QPID_LOG(error, exceptionHolder.what());
    }
    if (detachedLifetime == 0) {
        handleClosed();
}
}

void SessionImpl::requestTimeout(uint32_t t)
{
    Lock l(state);
    detachedLifetime = t;
    proxy.timeout(t);
}

void SessionImpl::timeout(uint32_t t)
{
    Lock l(state);
    detachedLifetime = t;
}

void SessionImpl::commandPoint(const framing::SequenceNumber& id, uint64_t offset)
{
    if (offset) throw NotImplementedException("Non-zero byte offset not yet supported for command-point");

    Lock l(state);
    nextIn = id;
}

void SessionImpl::expected(const framing::SequenceSet& commands, const framing::Array& fragments)
{
    if (!commands.empty() || fragments.encodedSize()) {
        throw NotImplementedException("Session resumption not yet supported");
    }
}

void SessionImpl::confirmed(const framing::SequenceSet& /*commands*/, const framing::Array& /*fragments*/)
{
    //don't really care too much about this yet
}

void SessionImpl::completed(const framing::SequenceSet& commands, bool timelyReply)
{
    Lock l(state);
    incompleteOut.remove(commands);
    state.notifyAll();//notify any waiters of completion
    completedOut.add(commands);
    //notify any waiting results of completion
    results.completed(commands);

    if (timelyReply) {
        proxy.knownCompleted(completedOut);
        completedOut.clear();
    }
}

void SessionImpl::knownCompleted(const framing::SequenceSet& commands)
{
    Lock l(state);
    completedIn.remove(commands);
}

void SessionImpl::flush(bool expected, bool confirmed, bool completed)
{
    Lock l(state);
    if (expected) {
        proxy.expected(SequenceSet(nextIn), Array());
    }
    if (confirmed) {
        proxy.confirmed(completedIn, Array());
    }
    if (completed) {
        proxy.completed(completedIn, true);
    }
}

void SessionImpl::sendCompletion()
{
    Lock l(state);
    sendCompletionImpl();
}

void SessionImpl::sendFlush()
{
    Lock l(state);
    proxy.flush(false, false, true);
}

void SessionImpl::sendCompletionImpl()
{
    proxy.completed(completedIn, completedIn.span() > 1000);
}

void SessionImpl::gap(const framing::SequenceSet& /*commands*/)
{
    throw NotImplementedException("gap not yet supported");
}

void SessionImpl::sync() {}

void SessionImpl::result(const framing::SequenceNumber& commandId, const std::string& value)
{
    Lock l(state);
    results.received(commandId, value);
}

void SessionImpl::exception(uint16_t errorCode,
                            const framing::SequenceNumber& commandId,
                            uint8_t classCode,
                            uint8_t commandCode,
                            uint8_t /*fieldIndex*/,
                            const std::string& description,
                            const framing::FieldTable& /*errorInfo*/)
{
    Lock l(state);
    setExceptionLH(createSessionException(errorCode, description));
    QPID_LOG(warning, "Exception received from broker: " << exceptionHolder.what()
             << " [caused by " << commandId << " " << classCode << ":" << commandCode << "]");

    if (detachedLifetime)
        setTimeout(0);
}

//private utility methods:

inline void SessionImpl::setState(State s) //call with lock held
{
    state = s;
}

inline void SessionImpl::waitFor(State s) //call with lock held
{
    // We can be DETACHED at any time
    if (s == DETACHED) state.waitFor(DETACHED);
    else state.waitFor(States(s, DETACHED));
    check();
}

void SessionImpl::check() const  //call with lock held.
{
    exceptionHolder.raise();
}

void SessionImpl::checkOpen() const  //call with lock held.
{
    check();
    if (state != ATTACHED) {
        throw NotAttachedException(QPID_MSG("Session " << getId() << " isn't attached"));
    }
}

void SessionImpl::assertOpen() const
{
    Lock l(state);
    checkOpen();
}

bool SessionImpl::hasError() const
{
    Lock l(state);
    return !exceptionHolder.empty();
}

void SessionImpl::handleClosed()
{
    demux.close(exceptionHolder.empty() ?
                sys::ExceptionHolder(new ClosedException()) : exceptionHolder);
    results.close();
}

uint32_t SessionImpl::setTimeout(uint32_t seconds) {
    proxy.requestTimeout(seconds);
    // FIXME aconway 2008-10-07: wait for timeout response from broker
    // and use value retured by broker.
    detachedLifetime = seconds;
    return detachedLifetime;
}

uint32_t SessionImpl::getTimeout() const {
    return detachedLifetime;
}

boost::shared_ptr<ConnectionImpl> SessionImpl::getConnection()
{
    return connection;
}

}}