Crate vsdb

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VSDB is a ‘Git’ in the form of KV-database.

Based on the powerful version control function of VSDB, you can easily give your data structure the ability to version management.

Make everything versioned !!

Highlights

Support Git-like verison operations, such as:
- Create countless branches and merge them to their parents
- Rolling back a ‘branch’ to a specified historical ‘version’
- Querying the historical value of a key on the specified ‘branch’
Most APIs is similar as the coresponding data structures in the standard library
- Use Vecx just like Vec
- Use Mapx just like HashMap
- Use MapxOrd just like BTreeMap
- …

Practical scenarios

Process CheckTx, DeliverTx, Commit … in ‘Tendermint ABCI’
Handle folk chain branches, e.g.:
- Handling ‘chain folk’ or ‘uncle blocks’ in non-deterministic consensus like ‘POW’
- Handle temporary ‘chain folk’ in a hybrid consensus like ‘Babe + Grandpa’(substrate)
Support some special APIs of ‘ETH Web3’ in the form of ‘trial run’
…

the #[derive(Vs)] macro can be applied to structures whose internal fields are all types defined in VSDB (primitive types and their collections are also supported), but can not be applied to nesting wrapper among VSDB-types, we recommend you to use the multi-key APIs if you indeed require these functions(better performance also), or you will have to implement the VsMgmt trait manually.

This data structure can be handled correctly by #[derive(Vs)]:

use std::collections::{
    HashMap, HashSet, BTreeSet, VecDeque, LinkedList
};
use std::sync::atomic::AtomicU64;
use std::marker::PhantomData;
use ruc::*;
use vsdb::{
    BranchName, VersionName, ParentBranchName,
    MapxVs, MapxOrdVs, OrphanVs, VsMgmt, Vs,
    VecxVs, impl_vs_methods_nope
};

#[derive(Vs)]
struct GoodCase<K, T> {
    a: VecxVs<i64>,
    b: SubItem0,
    c: SubItem1,
    d: SubItem2,
    e: u8,
    f: Vec<i16>,
    g: VecDeque<i64>,
    h: BTreeSet<u16>,
    i: HashMap<K, AtomicU64>,
    j: HashSet<i32>,
    k: LinkedList<()>,
    l: Box<dyn AsRef<bool>>,
    m: Box<dyn AsRef<[Vec<u128>]>>,
    n: PhantomData<T>,
}

#[derive(Vs)]
struct SubItem0(MapxVs<u8, u8>, VecxVs<u8>);

#[derive(Vs)]
struct SubItem1 {
    a: OrphanVs<i16>,
    b: MapxOrdVs<String, u8>
}

#[derive(Vs)]
struct SubItem2 {
    a: i8,
    b: u128
}

// // A nope implementation of `VsMgmt` for custom stateless types.
// // the `#[derive(Vs)]` on 'SubItem2' is same as this implementation.
// impl VsMgmt for SubItem2 {
//     impl_vs_methods_nope!();
// }

But this one can NOT be handled correctly by #[derive(Vs)]:

use vsdb::{Vs, VecxVs, MapxVs};
use ruc::*;

// It can be compiled, but the result is wrong !
// The versioned methods of the inner 'MapxVs<u8, u8>' will missing,
// We recommend you to use the 'multi-key' APIs of VSDB, or
// you will have to implement the 'VsMgmt' trait manually.
#[derive(Vs)]
struct BadCase {
    a: VecxVs<MapxVs<u8, u8>>,
}

Please check the multi-key functions if you have requirements of the above or similar scenes.

Compilation features

[default] sled_engine, use sled as the backend database
- Faster compilation speed
- Support for compiling into a statically linked object
rocks_engine, use rocksdb as the backend database
- Faster running speed
- Can not be compiled into a statically linked object
[default] json_codec, use serde_json as the codec
- Better generality and compatibility
bcs_codec, use bcs as the codec
- Faster running speed
- Created by the ‘Libre’ project of Facebook
- Security reinforcement for blockchain scenarios
[default] derive, enable the Vs procedural macro
compress, enable compression in the backend database
extra_types, implement VsMgmt for some common extra types
- For example: H256 and H160 of the primitive-types crate