//! db modules

 //!

 //! This library provides types and builder functions for working with

 //! databases. Currently the only backend supported is RocksDB.

 #![feature(associated_type_defaults)]

 use obj::Configure;

 #[cfg(feature = "rocksdb")]

 pub use rocksdb;

 use std::path::PathBuf;

 mod err;

 pub use err::{Error, Result};

 #[cfg(test)]

 mod tests;

 pub trait Db {

   #[cfg(feature = "rocksdb")]

   type DB = rocksdb::DB;

   #[cfg(not(feature = "rocksdb"))]

   type DB;

   fn db_init(&self) -> Result<Self::DB>;

   fn db_init_mut(&mut self) -> Result<()>;

   fn db_open(&self) -> Result<()>;

   fn db_close(&self) -> Result<()>;

   fn db_close_mut(&mut self) -> Result<()>;

   fn db_query(&self) -> Result<()>;

   fn db_transaction(&self) -> Result<()>;

 }

 pub trait DbConfigExt: Configure {

   fn db_path(self) -> Option<PathBuf>;

   fn db_user(self) -> Option<String>;

   fn set_db_config_value(&mut self, key: &str, val: &str) -> Option<String>;

   fn get_db_config_value(self, key: &str) -> Option<String>;

 }