Anchor Pallet, On-chain Linked List

Anchor is an On-chain Linked List pallet for substrate, it is based on substrate transfer extension.
You can storage data on chain by anchor, as this way, it is a On-chain Key-value Storage.
Anchor is also can be treaded as Name Service, you can own special anchor name by initializing it.

Overview

Terminology

Anchor: The name saved in AnchorOwner storage. You can treaded it as the domain on anchor chain.
Protocol: Custom protocol, 256 bytes max.
Raw: Any data you want to storage on chain.

Unit Test

The unit test follow the substrate standard. Just change directory to frame/anchor, then run unit test as follow command.

    cargo clean
    cargo test

Compatibility

Compiled successful on https://github.com/paritytech/substrate/releases/tag/monthly-2023-02

Exposed Methods

set_anchor

Set anchor data function. There are two conditions. If the target anchor exsists, will check the ownership, then update the data. Otherwise, will initialize a new anchor.

    pub fn set_anchor(
      origin: OriginFor<T>,   //default
      key: Vec<u8>,           //Anchor name
      raw: Vec<u8>,           //raw data to storage
      protocol: Vec<u8>,      //data protocol, used to decide how to decode raw data
      pre:T::BlockNumber      //the previous block number which storage anchor data
    ) -> DispatchResult {
      // code here.
      Ok(())
    }

sell_anchor

Set the anchor on selling, two ways can be supported.

sell anchor freely
sell anchor to target account

    pub fn sell_anchor(
      origin: OriginFor<T>,   //default
      key: Vec<u8>,           //Anchor name
      cost: u32,              //unit accuracy
      target:<T::Lookup as StaticLookup>::Source  //target buyer SS58 address. If the same as owner, can be sold to anyone.
    ) -> DispatchResult {
      // code here.
      Ok(())
    }

unsell_anchor

Revoke the selling status.

    pub fn unsell_anchor(
      origin: OriginFor<T>,   //default
      key: Vec<u8>,           //Anchor name
    ) -> DispatchResult {
      // code here.
      Ok(())
    }

buy_anchor

Buy the selling anchor.

    pub fn buy_anchor(
        origin: OriginFor<T>,    //default
      key: Vec<u8>,            //Anchor name
    ) -> DispatchResult {
      // code here.
      Ok(())
    }

Storages

AnchorOwner

  // (T::AccountId,T::BlockNumber)
  //  T::AccountId, the anchor owner ss58 address
  //  T::BlockNumber, last block number when updated data successfully.
  pub(super) type AnchorOwner<T: Config> = StorageMap < 
      _, 
      Twox64Concat,
      Vec<u8>,                        //anchor name
      (T::AccountId,T::BlockNumber)   //check the head lines
  >;

SellList

  // (T::AccountId, u32,T::AccountId)
  // T::AccountId, the anchor owner ss58 address
  // u32, the sell price for the anchor
  // T::AccountId, the target buyer. If the same as owner, it is free to buy.
  pub(super) type SellList<T: Config> = StorageMap<
      _,
      Twox64Concat,
      Vec<u8>,                            //anchor name
      (T::AccountId,u32,T::AccountId)     //check the head lines
  >;

Events

AnchorToSell

When an anchor is set to selling status, will trigger this event.

  #[pallet::event]
  #[pallet::generate_deposit(pub(super) fn deposit_event)]
  pub enum Event<T: Config> {
    AnchorToSell(T::AccountId,u32,T::AccountId),  //(owner, price , target)
  }

doutv / pallet-anchor