RC9/qpid/cpp/src/qpid/broker/MessageBuilder.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 "MessageBuilder.h"

#include "Message.h"
#include "MessageStore.h"
#include "NullMessageStore.h"
#include "qpid/framing/AMQFrame.h"
#include "qpid/framing/reply_exceptions.h"

using boost::intrusive_ptr;
using namespace qpid::broker;
using namespace qpid::framing;

namespace 
{
    std::string type_str(uint8_t type);
}
MessageBuilder::MessageBuilder(MessageStore* const _store, uint64_t _stagingThreshold) : 
    state(DORMANT), store(_store), stagingThreshold(_stagingThreshold), staging(false) {}

void MessageBuilder::handle(AMQFrame& frame)
{
    uint8_t type = frame.getBody()->type();
    switch(state) {
    case METHOD:
        checkType(METHOD_BODY, type);
        state = HEADER;
        break;
    case HEADER:
        if (type == CONTENT_BODY) {
            //TODO: rethink how to handle non-existent headers(?)...
            //didn't get a header: add in a dummy
            AMQFrame header;
            header.setBody(AMQHeaderBody());
            header.setBof(false);
            header.setEof(false);
            message->getFrames().append(header);            
        } else if (type != HEADER_BODY) {
            throw CommandInvalidException(
                QPID_MSG("Invalid frame sequence for message, expected header or content got " 
                         << type_str(type) << ")"));
        }
        state = CONTENT;
        break;
    case CONTENT:
        checkType(CONTENT_BODY, type);
        break;
    default:
        throw CommandInvalidException(QPID_MSG("Invalid frame sequence for message (state=" << state << ")"));
    }
    if (staging) {
        intrusive_ptr<const PersistableMessage> cpmsg = boost::static_pointer_cast<const PersistableMessage>(message);
        store->appendContent(cpmsg, frame.castBody<AMQContentBody>()->getData());
    } else {
        message->getFrames().append(frame);
        //have we reached the staging limit? if so stage message and release content
        if (state == CONTENT 
            && stagingThreshold 
            && message->getFrames().getContentSize() >= stagingThreshold
            && !NullMessageStore::isNullStore(store)) 
        {
            message->releaseContent(store); 
            staging = true;
        }
    }
}

void MessageBuilder::end()
{
    message = 0;
    state = DORMANT;
    staging = false;
}

void MessageBuilder::start(const SequenceNumber& id)
{
    message = intrusive_ptr<Message>(new Message(id));
    state = METHOD;
    staging = false;
}

namespace {

const std::string HEADER_BODY_S = "HEADER";
const std::string METHOD_BODY_S = "METHOD";
const std::string CONTENT_BODY_S = "CONTENT";
const std::string HEARTBEAT_BODY_S = "HEARTBEAT";
const std::string UNKNOWN = "unknown";

std::string type_str(uint8_t type) 
{
    switch(type) {
    case METHOD_BODY: return METHOD_BODY_S;
    case HEADER_BODY: return HEADER_BODY_S;
    case CONTENT_BODY: return CONTENT_BODY_S;
    case HEARTBEAT_BODY: return HEARTBEAT_BODY_S;
    }
    return UNKNOWN;
}

}

void MessageBuilder::checkType(uint8_t expected, uint8_t actual)
{
    if (expected != actual) {
        throw CommandInvalidException(QPID_MSG("Invalid frame sequence for message (expected " 
                                               << type_str(expected) << " got " << type_str(actual) << ")"));
    }
}