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#pragma once
#include <string>
#include <functional>
#include <memory>
namespace libdb {
extern "C" {
#include <db.h>
}
}
namespace crepe {
/**
* \brief Berkeley DB facade
*
* Berkeley DB is a simple key-value database that stores arbitrary data as
* both key and value. This facade uses STL strings as keys/values.
*/
class DB {
public:
/**
* \param path The path of the database (created if nonexistant)
*/
DB(const std::string & path);
virtual ~DB() = default;
public:
/**
* \brief Get a value from the database, or throw an exception
*
* \param key The value key
*
* \return The value
*
* \throws Exception if value is not found in DB or other error occurs
*/
std::string get(const std::string & key);
/**
* \brief Set (create or overwrite) a value in the database
*
* \param key The value key
* \param value The value to store
*
* \throws Exception if an error occurs
*/
void set(const std::string & key, const std::string & value);
/**
* \brief Check if a key exists in the database
*
* \param key The value key
*
* \returns True if the key exists, or false if it does not
*/
bool has(const std::string & key) noexcept;
private:
//! RAII wrapper around \c DB struct
std::unique_ptr<libdb::DB, std::function<void(libdb::DB *)>> db;
//! RAII wrapper around \c DBC struct
std::unique_ptr<libdb::DBC, std::function<void(libdb::DBC *)>> cursor;
private:
/**
* \brief Convert an STL string to DBT (data base thang)
*
* \param thing Input data
* \return \c DBT with the same data as input \c thing
*/
libdb::DBT to_thing(const std::string & thing) const noexcept;
};
}
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