lmdbal/storage.hpp

/*
 * Squawk messenger. 
 * Copyright (C) 2019 Yury Gubich <blue@macaw.me>
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#ifndef CORE_STORAGE_HPP
#define CORE_STORAGE_HPP

#include <QStandardPaths>
#include <QDir>

#include "storage.h"
#include <cstring>

template <class K, class V>
Core::Storage<K, V>::Storage(const QString& p_name):
    name(p_name),
    opened(false),
    environment(),
    base()
{
}

template <class K, class V>
Core::Storage<K, V>::~Storage()
{
    close();
}

template <class K, class V>
void Core::Storage<K, V>::open()
{
    if (!opened) {
        mdb_env_create(&environment);
        QString path(QStandardPaths::writableLocation(QStandardPaths::CacheLocation));
        path += "/" + name;
        QDir cache(path);
        
        if (!cache.exists()) {
            bool res = cache.mkpath(path);
            if (!res) {
                throw Directory(path.toStdString());
            }
        }
        
        mdb_env_set_maxdbs(environment, 1);
        mdb_env_set_mapsize(environment, 10UL * 1024UL * 1024UL);
        mdb_env_open(environment, path.toStdString().c_str(), 0, 0664);
        
        MDB_txn *txn;
        mdb_txn_begin(environment, NULL, 0, &txn);
        mdb_dbi_open(txn, "base", MDB_CREATE, &base);
        mdb_txn_commit(txn);
        opened = true;
    }
}

template <class K, class V>
void Core::Storage<K, V>::close()
{
    if (opened) {
        mdb_dbi_close(environment, base);
        mdb_env_close(environment);
        opened = false;
    }
}

template <class K, class V>
void Core::Storage<K, V>::addRecord(const K& key, const V& value)
{
    if (!opened) {
        throw Closed("addRecord", name.toStdString());
    }
    QByteArray ba;
    QDataStream ds(&ba, QIODevice::WriteOnly);
    ds << value;
    
    MDB_val lmdbKey, lmdbData;
    lmdbKey << key;

    lmdbData.mv_size = ba.size();
    lmdbData.mv_data = (uint8_t*)ba.data();
    MDB_txn *txn;
    mdb_txn_begin(environment, NULL, 0, &txn);
    int rc;
    rc = mdb_put(txn, base, &lmdbKey, &lmdbData, MDB_NOOVERWRITE);
    if (rc != 0) {
        mdb_txn_abort(txn);
        if (rc == MDB_KEYEXIST) {
            throw Exist(name.toStdString(), std::to_string(key));
        } else {
            throw Unknown(name.toStdString(), mdb_strerror(rc));
        }
    } else {
        mdb_txn_commit(txn);
    }
}

template <class K, class V>
void Core::Storage<K, V>::changeRecord(const K& key, const V& value)
{
    if (!opened) {
        throw Closed("changeRecord", name.toStdString());
    }

    QByteArray ba;
    QDataStream ds(&ba, QIODevice::WriteOnly);
    ds << value;
    
    MDB_val lmdbKey, lmdbData;
    lmdbKey << key;
    lmdbData.mv_size = ba.size();
    lmdbData.mv_data = (uint8_t*)ba.data();
    MDB_txn *txn;
    mdb_txn_begin(environment, NULL, 0, &txn);
    int rc;
    rc = mdb_put(txn, base, &lmdbKey, &lmdbData, 0);
    if (rc != 0) {
        mdb_txn_abort(txn);
        if (rc) {
            throw Unknown(name.toStdString(), mdb_strerror(rc));
        }
    } else {
        mdb_txn_commit(txn);
    }
}

template <class K, class V>
V Core::Storage<K, V>::getRecord(const K& key) const
{
    if (!opened) {
        throw Closed("addElement", name.toStdString());
    }
    
    MDB_val lmdbKey, lmdbData;
    lmdbKey << key;
    
    MDB_txn *txn;
    int rc;
    mdb_txn_begin(environment, NULL, MDB_RDONLY, &txn);
    rc = mdb_get(txn, base, &lmdbKey, &lmdbData);
    if (rc) {
        mdb_txn_abort(txn);
        if (rc == MDB_NOTFOUND) {
            throw NotFound(std::to_string(key), name.toStdString());
        } else {
            throw Unknown(name.toStdString(), mdb_strerror(rc));
        }
    } else {
        QByteArray ba((char*)lmdbData.mv_data, lmdbData.mv_size);
        QDataStream ds(&ba, QIODevice::ReadOnly);
        V value;
        ds >> value;
        mdb_txn_abort(txn);

        return value;
    }
}

template <class K, class V>
void Core::Storage<K, V>::removeRecord(const K& key)
{
    if (!opened) {
        throw Closed("addElement", name.toStdString());
    }
    
    MDB_val lmdbKey;
    lmdbKey << key;
    
    MDB_txn *txn;
    int rc;
    mdb_txn_begin(environment, NULL, 0, &txn);
    rc = mdb_del(txn, base, &lmdbKey, NULL);
    if (rc) {
        mdb_txn_abort(txn);
        if (rc == MDB_NOTFOUND) {
            throw NotFound(std::to_string(key), name.toStdString());
        } else {
            throw Unknown(name.toStdString(), mdb_strerror(rc));
        }
    } else {
        mdb_txn_commit(txn);
    }
}

template <class K, class V>
QString Core::Storage<K, V>::getName() const {
    return name;}

MDB_val& operator << (MDB_val& data, const QString& value) {
    QByteArray ba = value.toUtf8();
    data.mv_size = ba.size();
    data.mv_data = ba.data();
    return data;
}
MDB_val& operator >> (MDB_val& data, QString& value) {
    value = QString::fromUtf8((const char*)data.mv_data, data.mv_size);
    return data;
}

MDB_val& operator << (MDB_val& data, uint32_t& value) {
    data.mv_size = 4;
    data.mv_data = &value;
    return data;
}
MDB_val& operator >> (MDB_val& data, uint32_t& value) {
    std::memcpy(&value, data.mv_data, data.mv_size);
    return data;
}

std::string std::to_string(const QString& str) {
    return str.toStdString();
}
#endif //CORE_STORAGE_HPP