DataStorage.cpp

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/*
 * DataStorage.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 "storage/DataStorage.h"
#include <typeinfo>
#include <sstream>
#include <iomanip>
#include <list>

#include <string.h>
#include <stdlib.h>
#include <iostream>
#include <fstream>
#include <cstring>
#include <cerrno>

namespace dtn
{
        namespace storage
        {
                DataStorage::Hash::Hash()
                 : value("this-hash-value-is-empty")
                {}

                DataStorage::Hash::Hash(const std::string &v)
                 : value(v)
                {
                }

                DataStorage::Hash::Hash(const DataStorage::Container &container)
                 : value(container.getId())
                { }

                DataStorage::Hash::Hash(const ibrcommon::File &file) : value(file.getBasename()) {}
                DataStorage::Hash::~Hash() {}

                bool DataStorage::Hash::operator!=(const DataStorage::Hash &other) const
                {
                        return (value != other.value);
                }

                bool DataStorage::Hash::operator==(const DataStorage::Hash &other) const
                {
                        return (value == other.value);
                }

                bool DataStorage::Hash::operator<(const DataStorage::Hash &other) const
                {
                        return (value < other.value);
                }

                DataStorage::istream::istream(ibrcommon::Mutex &mutex, const ibrcommon::File &file)
                 : ibrcommon::File(file), _stream(NULL), _lock(mutex)
                {
                        _lock.enter();
                        _stream = new std::ifstream(getPath().c_str(), ios_base::in | ios_base::binary);
                }

                DataStorage::istream::~istream()
                {
                        if (_stream != NULL)
                        {
                                delete _stream;
                                _lock.leave();
                        }
                }

                std::istream& DataStorage::istream::operator*()
                { return *_stream; }

                DataStorage::DataStorage(Callback &callback, const ibrcommon::File &path, unsigned int write_buffer, bool initialize)
                 : _callback(callback), _path(path), _tasks(), _store_sem(write_buffer), _store_limited(write_buffer > 0), _faulty(false)
                // limit the number of bundles in the write buffer
                {
                        // initialize the storage
                        if (initialize)
                        {
                                if (_path.exists())
                                {
                                        // remove all files in the path
                                        std::list<ibrcommon::File> files;
                                        _path.getFiles(files);

                                        for (std::list<ibrcommon::File>::iterator iter = files.begin(); iter != files.end(); ++iter)
                                        {
                                                (*iter).remove(true);
                                        }
                                }
                                else
                                {
                                        // create the path
                                        ibrcommon::File::createDirectory(_path);
                                }
                        }
                }

                DataStorage::~DataStorage()
                {
                        _tasks.abort();
                        join();

                        // delete all task objects
                        try {
                                while (true)
                                {
                                        Task *t = _tasks.getnpop(false);
                                        delete t;
                                }
                        } catch (const ibrcommon::QueueUnblockedException&) {
                                // exit
                        }
                }

                void DataStorage::reset()
                {
                        JoinableThread::reset();
                }

                void DataStorage::setFaulty(bool mode)
                {
                        _faulty = mode;
                }

                void DataStorage::iterateAll()
                {
                        std::list<ibrcommon::File> files;
                        _path.getFiles(files);

                        for (std::list<ibrcommon::File>::const_iterator iter = files.begin(); iter != files.end(); ++iter)
                        {
                                if (!(*iter).isSystem() && !(*iter).isDirectory())
                                {
                                        DataStorage::Hash hash(*iter);
                                        DataStorage::istream stream(_global_mutex, *iter);

                                        _callback.iterateDataStorage(hash, stream);
                                }
                        }
                }

                void DataStorage::store(const DataStorage::Hash &hash, DataStorage::Container *data)
                {
                        // wait for resources
                        if (_store_limited) _store_sem.wait();

                        // put the task into the queue
                        _tasks.push( new StoreDataTask(hash, data) );
                }

                const DataStorage::Hash DataStorage::store(DataStorage::Container *data)
                {
                        // create a corresponding hash
                        DataStorage::Hash hash(*data);
                        store(hash, data);
                        return hash;
                }

                DataStorage::istream DataStorage::retrieve(const DataStorage::Hash &hash) throw (DataNotAvailableException)
                {
                        ibrcommon::File file = _path.get(hash.value);

                        if (!file.exists())
                        {
                                throw DataNotAvailableException("file " + file.getPath() + " not found");
                        }

                        return DataStorage::istream(_global_mutex, file);
                }

                void DataStorage::remove(const DataStorage::Hash &hash)
                {
                        _tasks.push( new RemoveDataTask(hash) );
                }

                void DataStorage::wait()
                {
                        _tasks.wait(ibrcommon::Queue< Task* >::QUEUE_EMPTY);
                }

                void DataStorage::__cancellation() throw ()
                {
                        _tasks.abort();
                }

                void DataStorage::run() throw ()
                {
                        try {
                                while (true)
                                {
                                        Task *t = _tasks.get(true);

                                        try {
                                                StoreDataTask &store = dynamic_cast<StoreDataTask&>(*t);

                                                try {
                                                        ibrcommon::File destination = _path.get(store.hash.value);

                                                        {
                                                                ibrcommon::MutexLock l(_global_mutex);
                                                                std::ofstream stream(destination.getPath().c_str(), ios::out | ios::binary | ios::trunc);

                                                                // check the streams health
                                                                if (!stream.good() || _faulty)
                                                                {
                                                                        std::stringstream ss; ss << "unable to open filestream [" << std::strerror(errno) << "]";
                                                                        throw ibrcommon::IOException(ss.str());
                                                                }

                                                                store._container->serialize(stream);
                                                                stream.close();
                                                        }

                                                        // release resources
                                                        if (_store_limited) _store_sem.post();

                                                        // notify the stored item
                                                        _callback.eventDataStorageStored(store.hash);
                                                } catch (const ibrcommon::Exception &ex) {
                                                        // release resources
                                                        if (_store_limited) _store_sem.post();

                                                        // notify the fail of store action
                                                        _callback.eventDataStorageStoreFailed(store.hash, ex);
                                                }
                                        } catch (const std::bad_cast&) {
                                        }

                                        try {
                                                RemoveDataTask &remove = dynamic_cast<RemoveDataTask&>(*t);

                                                try {
                                                        ibrcommon::File destination = _path.get(remove.hash.value);
                                                        {
                                                                ibrcommon::MutexLock l(_global_mutex);
                                                                if (!destination.exists())
                                                                {
                                                                        throw DataNotAvailableException();
                                                                }
                                                                destination.remove();
                                                        }
                                                        _callback.eventDataStorageRemoved(remove.hash);
                                                } catch (const ibrcommon::Exception &ex) {
                                                        _callback.eventDataStorageRemoveFailed(remove.hash, ex);
                                                }
                                        } catch (const std::bad_cast&) {

                                        }

                                        delete t;
                                        _tasks.pop();
                                }
                        } catch (const ibrcommon::QueueUnblockedException&) {
                                // exit
                        }
                }

                DataStorage::Container::~Container() {}
                DataStorage::Task::~Task() {}

                DataStorage::StoreDataTask::StoreDataTask(const Hash &h, Container *c)
                 : hash(h), _container(c)
                {}

                DataStorage::StoreDataTask::~StoreDataTask()
                {
                }

                DataStorage::RemoveDataTask::RemoveDataTask(const Hash &h) : hash(h)
                {}

                DataStorage::RemoveDataTask::~RemoveDataTask()
                {
                }
        }
}