BundleStreamBuf.cpp

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/*
 * BundleStreamBuf.cpp
 *
 * Copyright (C) 2011 IBR, TU Braunschweig
 *
 * Written-by: Johannes Morgenroth <morgenroth@ibr.cs.tu-bs.de>
 *
 * Licensed 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 "BundleStreamBuf.h"
#include "core/BundleCore.h"
#include <ibrdtn/data/StreamBlock.h>
#include <ibrcommon/Logger.h>
#include <ibrcommon/TimeMeasurement.h>

namespace dtn
{
        namespace api
        {
                BundleStreamBuf::BundleStreamBuf(BundleStreamBufCallback &callback, const dtn::data::Length chunk_size, bool wait_seq_zero)
                 : _callback(callback), _in_buf(BUFF_SIZE), _out_buf(BUFF_SIZE),
                   _chunk_size(chunk_size), _chunk_payload(ibrcommon::BLOB::create()), _chunk_offset(0), _in_seq(0),
                   _out_seq(0), _streaming(wait_seq_zero), _first_chunk(true), _last_chunk_received(false), _timeout_receive(0)
                {
                        // Initialize get pointer.  This should be zero so that underflow is called upon first read.
                        setg(0, 0, 0);
                        setp(&_in_buf[0], &_in_buf[BUFF_SIZE - 1]);
                }

                BundleStreamBuf::~BundleStreamBuf()
                {
                }

                int BundleStreamBuf::sync()
                {
                        int ret = std::char_traits<char>::eq_int_type(this->overflow(
                                        std::char_traits<char>::eof()), std::char_traits<char>::eof()) ? -1
                                        : 0;

                        // send the current chunk and clear it
                        flushPayload(true);

                        return ret;
                }

                std::char_traits<char>::int_type BundleStreamBuf::overflow(std::char_traits<char>::int_type c)
                {
                        char *ibegin = &_in_buf[0];
                        char *iend = pptr();

                        // mark the buffer as free
                        setp(&_in_buf[0], &_in_buf[0] + BUFF_SIZE - 1);

                        if (!std::char_traits<char>::eq_int_type(c, std::char_traits<char>::eof()))
                        {
                                *iend++ = std::char_traits<char>::to_char_type(c);
                        }

                        // if there is nothing to send, just return
                        if ((iend - ibegin) == 0)
                        {
                                return std::char_traits<char>::not_eof(c);
                        }

                        // copy data into the bundles payload
                        BundleStreamBuf::append(_chunk_payload, &_in_buf[0], iend - ibegin);

                        // if size exceeds chunk limit, send it
                        if (_chunk_payload.iostream().size() > static_cast<std::streamsize>(_chunk_size))
                        {
                                flushPayload();
                        }

                        return std::char_traits<char>::not_eof(c);
                }

                void BundleStreamBuf::flushPayload(bool final)
                {
                        // do not send a bundle if there are no bytes buffered
                        // and no bundle has been sent before
                        if ((_first_chunk) && (_chunk_payload.iostream().size() == 0))
                        {
                                return;
                        }

                        // create an empty bundle
                        dtn::data::Bundle b;

                        dtn::data::StreamBlock &block = b.push_front<dtn::data::StreamBlock>();
                        block.setSequenceNumber(_out_seq);
                        if (final) block.set(dtn::data::StreamBlock::STREAM_END, true);
                        block.set(dtn::data::StreamBlock::STREAM_BEGIN, _first_chunk);
                        if (_first_chunk) _first_chunk = false;

                        // add tmp payload to the bundle
                        b.push_back(_chunk_payload);

                        // send the current chunk
                        _callback.put(b);

                        // and clear the payload
                        _chunk_payload = ibrcommon::BLOB::create();

                        // increment the sequence number
                        _out_seq++;
                }

                void BundleStreamBuf::setChunkSize(const dtn::data::Length &size)
                {
                        _chunk_size = size;
                }

                void BundleStreamBuf::setTimeout(const dtn::data::Timeout &timeout)
                {
                        _timeout_receive = timeout;
                }

                void BundleStreamBuf::append(ibrcommon::BLOB::Reference &ref, const char* data, const dtn::data::Length &length)
                {
                        ibrcommon::BLOB::iostream stream = ref.iostream();
                        (*stream).seekp(0, ios::end);
                        (*stream).write(data, length);
                }

                std::char_traits<char>::int_type BundleStreamBuf::underflow()
                {
                        // return with EOF if the last chunk was received
                        if (_last_chunk_received)
                        {
                                return std::char_traits<char>::eof();
                        }

                        // receive chunks until the next sequence number is received
                        while (_chunks.empty())
                        {
                                // request the next bundle
                                dtn::data::MetaBundle b = _callback.get();

                                IBRCOMMON_LOGGER_DEBUG_TAG("BundleStreamBuf", 40) << "bundle received" << IBRCOMMON_LOGGER_ENDL;

                                // create a chunk object
                                Chunk c(b);

                                if (c._seq >= _in_seq)
                                {
                                        IBRCOMMON_LOGGER_DEBUG_TAG("BundleStreamBuf", 40) << "bundle accepted, seq. no. " << c._seq << IBRCOMMON_LOGGER_ENDL;
                                        _chunks.insert(c);
                                }
                        }

                        ibrcommon::TimeMeasurement tm;
                        tm.start();

                        // while not the right sequence number received -> wait
                        while (_in_seq != (*_chunks.begin())._seq)
                        {
                                try {
                                        // request the next bundle
                                        dtn::data::MetaBundle b = _callback.get(_timeout_receive);
                                        IBRCOMMON_LOGGER_DEBUG_TAG("BundleStreamBuf", 40) << "bundle received" << IBRCOMMON_LOGGER_ENDL;

                                        // create a chunk object
                                        Chunk c(b);

                                        if (c._seq >= _in_seq)
                                        {
                                                IBRCOMMON_LOGGER_DEBUG_TAG("BundleStreamBuf", 40) << "bundle accepted, seq. no. " << c._seq << IBRCOMMON_LOGGER_ENDL;
                                                _chunks.insert(c);
                                        }
                                } catch (std::exception&) {
                                        // timed out
                                }

                                tm.stop();
                                if (((_timeout_receive > 0) && (tm.getSeconds() > _timeout_receive)) || !_streaming)
                                {
                                        // skip the missing bundles and proceed with the last received one
                                        _in_seq = (*_chunks.begin())._seq;

                                        // set streaming to active
                                        _streaming = true;
                                }
                        }

                        IBRCOMMON_LOGGER_DEBUG_TAG("BundleStreamBuf", 40) << "read the payload" << IBRCOMMON_LOGGER_ENDL;

                        // get the first chunk in the buffer
                        const Chunk &c = (*_chunks.begin());

                        if (c._meta != _current_bundle)
                        {
                                // load the bundle from storage
                                dtn::storage::BundleStorage &storage = dtn::core::BundleCore::getInstance().getStorage();
                                _current_bundle = storage.get(c._meta);

                                // process the bundle block (security, compression, ...)
                                dtn::core::BundleCore::processBlocks(_current_bundle);
                        }

                        const dtn::data::PayloadBlock &payload = _current_bundle.find<dtn::data::PayloadBlock>();
                        ibrcommon::BLOB::Reference r = payload.getBLOB();

                        bool end_of_stream = false;
                        std::streamsize bytes = 0;

                        // lock the stream while reading from it
                        {
                                // get stream lock
                                ibrcommon::BLOB::iostream stream = r.iostream();

                                // jump to the offset position
                                (*stream).seekg(_chunk_offset, ios::beg);

                                // copy the data of the last received bundle into the buffer
                                (*stream).read(&_out_buf[0], BUFF_SIZE);

                                // get the read bytes
                                bytes = (*stream).gcount();

                                // check for end of stream
                                end_of_stream = (*stream).eof();
                        }

                        if (end_of_stream)
                        {
                                // bundle consumed
                //              std::cerr << std::endl << "# " << c._seq << std::endl << std::flush;

                                // check if this was the last chunk
                                if (c._last)
                                {
                                        _last_chunk_received = true;
                                }

                                // set bundle as delivered
                                _callback.delivered(c._meta);

                                // delete the last chunk
                                _chunks.erase(c);

                                // reset the chunk offset
                                _chunk_offset = 0;

                                // increment sequence number
                                _in_seq++;

                                // if no more bytes are read, get the next bundle -> call underflow() recursive
                                if (bytes == 0)
                                {
                                        return underflow();
                                }
                        }
                        else
                        {
                                // increment the chunk offset
                                _chunk_offset += bytes;
                        }

                        // Since the input buffer content is now valid (or is new)
                        // the get pointer should be initialized (or reset).
                        setg(&_out_buf[0], &_out_buf[0], &_out_buf[0] + bytes);

                        return std::char_traits<char>::not_eof(_out_buf[0]);
                }

                BundleStreamBuf::Chunk::Chunk(const dtn::data::MetaBundle &m)
                 : _meta(m), _seq(0), _first(false), _last(false)
                {
                        dtn::storage::BundleStorage &storage = dtn::core::BundleCore::getInstance().getStorage();
                        dtn::data::Bundle bundle = storage.get(_meta);

                        try {
                                const dtn::data::StreamBlock &block = bundle.find<dtn::data::StreamBlock>();
                                _seq = block.getSequenceNumber();
                                _first = block.get(dtn::data::StreamBlock::STREAM_BEGIN);
                                _last = block.get(dtn::data::StreamBlock::STREAM_END);
                        } catch (const dtn::data::Bundle::NoSuchBlockFoundException&) { }
                }

                BundleStreamBuf::Chunk::~Chunk()
                {
                }

                bool BundleStreamBuf::Chunk::operator==(const Chunk& other) const
                {
                        return (_seq == other._seq);
                }

                bool BundleStreamBuf::Chunk::operator<(const Chunk& other) const
                {
                        return (_seq < other._seq);
                }
        } /* namespace data */
} /* namespace dtn */