API: Staking

Contract overview

Bios.sol - is the main kernel smartcontract with all the logic about consensus and staking. Its based on the QueueHelper that brings queue implementation code.

Functions

  • function freeze() payable public

Stake the specified amount of tokens. The value is on the contract account and thus inaccessible to the sender. Input parameter : “msg.value” the value to be staked. Output parameter : none

  • function melt(uint224 val) public

Unstake the specified value of tokens. The value is put to the melting queue and can be withdrawn after freezeGap. Input parameter : “val” - value to unstake. Output parameter : none

  • function withdraw() public

Withdraw the previously unstaked amount of tokens provided the freezeGap time had passed since its unstake. Every ‘unstake’ call must match ‘withdraw’ call. Takes the latest melting queue element and transfers its tokens amoun to the sender’s account. Input parameter : none Output parameter : none

  • function getFreeMeltingSlots() view public returns (uint8)

Service function, calculates the number of queue elements (slots) is aviable in the melting conveyer for the sender’s account. Every unstake call consumes a slot, every withdrawal releases it. Input parameter : none Output parameter : uint8 - slots number

  • function getMeltingHead() view public returns (uint224 stake, uint32 timestamp)

Service function, calculates the latest melting conveyer slot to bewithdrawn first. Return Stake and timestamp pair, where stake is the amount of money unstaked and timestamp is the time of the unstake call. Input parameter : none Output parameter : uint8 - stake Output parameter : uint8 - timestamp

  • function getFreeMeltingSlots() view public returns (uint8)

Service function, calculates the number of queue elements (slots) is aviable in the melting conveyer for the sender’s account. Every unstake call consumes a slot, every withdrawal releases it. Input parameter : none Output parameter : uint8 - number of free slots that could be used for the unstaking

  • function getMeltingHead() view public returns (uint224 stake, uint32 timestamp)

Service function, calculates the latest melting conveyer slot to be withdrawn first. Input parameter : none Output parameter : uint224 stake, uint32 timestamp - pair, where stake is the amount of money unstaked and timestamp is the time of the unstake call.

API Usage Example

Below you can see typical JS example of usage Bios.sol smartcontract.

  const gatewayUrl = 'http://148.251.152.112:18545/';  // url to the Papyrus testnet
  const biosAddress = '0x142ac51e2b05a107c1482f4832b73c5bc55b6fd5'; // Address of the Bios contract in the network

  const ether = 10 ** 18;
  let contract;
  let account;
  let web3;

  web3 = new Web3(window.web3.currentProvider);
  const accounts = await web3.eth.getAccounts();
  account = accounts[0];
  const netId = await web3.eth.net.getId();
  const balance = await web3.eth.getBalance(account);
  contract = new web3.eth.Contract(abi, biosAddress);

  //lets freeze some tokens
  contract.methods.freeze().send({ from: account, gas: 0, value })

  //lets unfreeze some tokens
  contract.methods.melt(value).send({ from: account, gas: 0 })

  //After freeze gap time - lets unfreeze our tokens
  contract.methods.withdraw().send({ from: account, gas: 100000 })