redis_rocksdb 0.3.9

use rocksdb::{DBAccess, DBIteratorWithThreadMode};

use crate::RrError;

/// 是对db的抽象，减少在事务与不带事务时，重复的代码，如果想要更好的性能，那么可以不使用这层实现
pub trait WrapDb {
	type Db: DBAccess;
	fn get(&self, key: &[u8]) -> Result<Option<Vec<u8>>, RrError>;
	fn put(&self, key: &[u8], value: &[u8]) -> Result<(), RrError>;
	fn delete(&self, key: &[u8]) -> Result<(), RrError>;
	/// 判断key是否存在， true存在，false不存在
	fn exist(&self, key: &[u8]) -> Result<bool, RrError>;
	/// 为了区分方法与字段，增加get
	fn get_db(&self) -> &Self::Db;
	fn prefix_iterator<'b: 'c, 'c>(&'b self, prefix: &[u8]) -> DBIteratorWithThreadMode<'c, Self::Db>;
}