BLOB.cpp

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/*
 * BLOB.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 "ibrcommon/data/BLOB.h"
#include "ibrcommon/thread/MutexLock.h"
#include "ibrcommon/Exceptions.h"
#include "ibrcommon/Logger.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <cstring>
#include <cerrno>
#include <vector>

#ifdef __DEVELOPMENT_ASSERTIONS__
#include <cassert>
#endif

namespace ibrcommon
{
        // maximum of concurrent opened files
        ibrcommon::Semaphore BLOB::_filelimit(10);

        // default BLOB provider - memory based; auto deletion enabled
        ibrcommon::BLOB::ProviderRef BLOB::provider(new ibrcommon::MemoryBLOBProvider(), true);

        BLOB::BLOB()
        { }

        BLOB::~BLOB()
        {
        }

        std::ostream& BLOB::copy(std::ostream &output, std::istream &input, const std::streamsize size, const size_t buffer_size)
        {
                // read payload
                std::vector<char> buffer(buffer_size);

                size_t remain = size;

                while (remain > 0)
                {
                        // something bad happened, abort!
                        if (input.bad())
                        {
                                std::stringstream errmsg; errmsg << "input stream went bad [" << std::strerror(errno) << "]; " << (size-remain) << " of " << size << " bytes copied";
                                throw ibrcommon::IOException(errmsg.str());
                        }

                        // reached EOF too early
                        if (input.eof())
                        {
                                std::stringstream errmsg; errmsg << "input stream reached EOF [" << std::strerror(errno) << "]; " << (size-remain) << " of " << size << " bytes copied";
                                throw ibrcommon::IOException(errmsg.str());
                        }

                        // check if the destination stream is ok
                        if (output.bad())
                        {
                                std::stringstream errmsg; errmsg << "output stream went bad [" << std::strerror(errno) << "]; " << (size-remain) << " of " << size << " bytes copied";
                                throw ibrcommon::IOException(errmsg.str());
                        }

                        // retry if the read failed
                        if (input.fail())
                        {
                                IBRCOMMON_LOGGER_TAG("BLOB::copy", warning) << "input stream failed [" << std::strerror(errno) << "]; " << (size-remain) << " of " << size << " bytes copied" << IBRCOMMON_LOGGER_ENDL;
                                input.clear();
                        }

                        // if the last write failed, then retry
                        if (output.fail())
                        {
                                IBRCOMMON_LOGGER_TAG("BLOB::copy", warning) << "output stream failed [" << std::strerror(errno) << "]; " << (size-remain) << " of " << size << " bytes copied" << IBRCOMMON_LOGGER_ENDL;
                                output.clear();
                        }
                        else
                        {
                                // read the full buffer size of less?
                                if (remain > buffer_size)
                                {
                                        input.read(&buffer[0], buffer_size);
                                }
                                else
                                {
                                        input.read(&buffer[0], remain);
                                }

                                // retry if the read failed
                                if (!input.eof() && input.fail()) continue;
                        }

                        // write the bytes to the BLOB
                        output.write(&buffer[0], input.gcount());

                        // shrink the remaining bytes by the red bytes
                        remain -= input.gcount();
                }

                return output;
        }

        ibrcommon::BLOB::Reference BLOB::create()
        {
                return ibrcommon::BLOB::provider.create();
        }

        ibrcommon::BLOB::Reference BLOB::open(const ibrcommon::File &f)
        {
                return ibrcommon::BLOB::Reference(new ibrcommon::FileBLOB(f));
        }

        void BLOB::changeProvider(BLOB::Provider *p, bool auto_delete)
        {
                ibrcommon::BLOB::provider.change(p, auto_delete);
        }

        BLOB::Provider::~Provider()
        { }

        BLOB::ProviderRef::ProviderRef(Provider *provider, bool auto_delete)
         : _provider(provider), _auto_delete(auto_delete)
        {
        }

        BLOB::ProviderRef::~ProviderRef()
        {
                if (_auto_delete)
                {
                        delete _provider;
                }
        }

        void BLOB::ProviderRef::change(BLOB::Provider *p, bool auto_delete)
        {
                if (_auto_delete)
                {
                        delete _provider;
                }

                _provider = p;
                _auto_delete = auto_delete;
        }

        BLOB::Reference BLOB::ProviderRef::create()
        {
                return _provider->create();
        }

        MemoryBLOBProvider::MemoryBLOBProvider()
        {
        }

        MemoryBLOBProvider::~MemoryBLOBProvider()
        {
        }

        ibrcommon::BLOB::Reference MemoryBLOBProvider::create()
        {
                return StringBLOB::create();
        }

        FileBLOBProvider::FileBLOBProvider(const File &path)
         : _tmppath(path)
        {
        }

        FileBLOBProvider::~FileBLOBProvider()
        {
        }

        ibrcommon::BLOB::Reference FileBLOBProvider::create()
        {
                return ibrcommon::BLOB::Reference(new TmpFileBLOB(_tmppath));
        }

        BLOB::Reference::Reference(const Reference &ref)
         : _blob(ref._blob)
        {
        }

        BLOB::Reference::~Reference()
        {
        }

        BLOB::iostream BLOB::Reference::iostream()
        {
                return BLOB::iostream(*_blob);
        }

        BLOB::Reference::Reference(BLOB *blob)
         : _blob(blob)
        {
        }

        const BLOB& BLOB::Reference::operator*() const
        {
                return *_blob;
        }

        BLOB::Reference MemoryBLOBProvider::StringBLOB::create()
        {
                BLOB::Reference ref(new MemoryBLOBProvider::StringBLOB());
                return ref;
        }

        void MemoryBLOBProvider::StringBLOB::clear()
        {
                _stringstream.str("");
        }

        MemoryBLOBProvider::StringBLOB::StringBLOB()
         : BLOB(), _stringstream()
        {

        }

        MemoryBLOBProvider::StringBLOB::~StringBLOB()
        {
        }

        void MemoryBLOBProvider::StringBLOB::open()
        {
                // set pointer to the beginning of the stream and remove any error flags
                _stringstream.clear();
                _stringstream.seekp(0);
                _stringstream.seekg(0);
        }

        void MemoryBLOBProvider::StringBLOB::close()
        {
        }

        std::streamsize MemoryBLOBProvider::StringBLOB::__get_size()
        {
                // store current position
                std::streamoff pos = _stringstream.tellg();

                _stringstream.seekg(0, std::ios_base::end);
                std::streamoff size = _stringstream.tellg();
                _stringstream.seekg(pos);

                return static_cast<std::streamsize>(size);
        }

        void FileBLOB::clear()
        {
                throw ibrcommon::IOException("clear is not possible on a read only file");
        }

        FileBLOB::FileBLOB(const File &f)
         : ibrcommon::BLOB(), _filestream(), _file(f)
        {
                if (!f.exists())
                {
                        throw ibrcommon::FileNotExistsException(f);
                }
        }

        FileBLOB::~FileBLOB()
        {
        }

        void FileBLOB::open()
        {
                BLOB::_filelimit.wait();

                // open the file
                _filestream.open(_file.getPath().c_str(), ios::in|ios::binary);

                if (!_filestream.is_open())
                {
                        throw ibrcommon::CanNotOpenFileException(_file);
                }
        }

        void FileBLOB::close()
        {
                // close the file
                _filestream.close();

                BLOB::_filelimit.post();
        }

        std::streamsize FileBLOB::__get_size()
        {
                return _file.size();
        }

        void FileBLOBProvider::TmpFileBLOB::clear()
        {
                // close the file
                _filestream.close();

                // open temporary file
                _filestream.open(_tmpfile.getPath().c_str(), ios::in | ios::out | ios::trunc | ios::binary );

                if (!_filestream.is_open())
                {
                        IBRCOMMON_LOGGER_TAG("TmpFileBLOB::clear", error) << "can not open temporary file " << _tmpfile.getPath() << IBRCOMMON_LOGGER_ENDL;
                        throw ibrcommon::CanNotOpenFileException(_tmpfile);
                }
        }

        FileBLOBProvider::TmpFileBLOB::TmpFileBLOB(const File &tmppath)
         : BLOB(), _filestream(), _fd(0), _tmpfile(tmppath, "blob")
        {
        }

        FileBLOBProvider::TmpFileBLOB::~TmpFileBLOB()
        {
                // delete the file if the last reference is destroyed
                _tmpfile.remove();
        }

        void FileBLOBProvider::TmpFileBLOB::open()
        {
                BLOB::_filelimit.wait();

                // open temporary file
                _filestream.open(_tmpfile.getPath().c_str(), ios::in | ios::out | ios::binary );

                if (!_filestream.is_open())
                {
                        IBRCOMMON_LOGGER_TAG("TmpFileBLOB::open", error) << "can not open temporary file " << _tmpfile.getPath() << IBRCOMMON_LOGGER_ENDL;
                        throw ibrcommon::CanNotOpenFileException(_tmpfile);
                }
        }

        void FileBLOBProvider::TmpFileBLOB::close()
        {
                // flush the filestream
                _filestream.flush();

                // close the file
                _filestream.close();

                BLOB::_filelimit.post();
        }

        std::streamsize FileBLOBProvider::TmpFileBLOB::__get_size()
        {
                return _tmpfile.size();
        }
}