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Pool

config.rs

Stores all relevant contract parameters.
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#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, JsonSchema)]
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pub struct Config {
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pub this: CanonicalAddr,
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pub owner: CanonicalAddr,
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pub beneficiary: CanonicalAddr,
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pub moneymarket: CanonicalAddr,
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pub atoken: CanonicalAddr,
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pub stable_denom: String,
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pub dp_token: CanonicalAddr,
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}
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this: the address of this pool contract.
owner: the owner address of this pool contract.
beneficiary: the address of which all interest collected from principal deposits are sent to. could be a single address, or a contract address that oversees additional distribution logic.
moneymarket: the address of the Anchor money market contract to accept deposits.
atoken: the address of the aUST token contract.
stable_denom: base Terra stablecoin denomination of this pool to be deposited to Anchor, i.e. uusd.
dp_token: the address of the DP token contract minted by this pool.
​

contract.rs

Defines logic entry points for InitMsg, HandleMsg and QueryMsg calls.
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pub fn init<S: Storage, A: Api, Q: Querier>(
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deps: &mut Extern<S, A, Q>,
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env: Env,
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msg: InitMsg,
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) -> StdResult<InitResponse> {
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let sender = env.message.sender;
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let raw_sender = deps.api.canonical_address(&sender)?;
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​
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let mut config = config::Config {
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this: deps.api.canonical_address(&env.contract.address)?,
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owner: raw_sender,
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beneficiary: deps.api.canonical_address(&msg.beneficiary)?,
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fee_collector: deps.api.canonical_address(&msg.fee_collector)?,
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exchange_rate_feeder: deps.api.canonical_address(&msg.exchange_rate_feeder)?,
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moneymarket: deps.api.canonical_address(&msg.moneymarket)?,
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stable_denom: String::default(),
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atoken: CanonicalAddr::default(),
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dp_token: CanonicalAddr::default(),
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};
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​
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let market_config = querier::anchor::config(deps, &config.moneymarket)?;
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​
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config.stable_denom = market_config.stable_denom.clone();
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config.atoken = deps.api.canonical_address(&market_config.aterra_contract)?;
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​
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config::store(&mut deps.storage, &config)?;
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​
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Ok(InitResponse {
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messages: vec![CosmosMsg::Wasm(WasmMsg::Instantiate {
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code_id: msg.dp_code_id,
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send: vec![],
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label: None,
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msg: to_binary(&Cw20InitMsg {
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name: format!("Deposit Token - {}", msg.pool_name),
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symbol: "PylonDP".to_string(),
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decimals: 6u8,
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initial_balances: vec![],
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mint: Some(MinterResponse {
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minter: env.contract.address.clone(),
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cap: None,
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}),
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init_hook: Some(Cw20InitHook {
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contract_addr: env.contract.address,
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msg: to_binary(&HandleMsg::RegisterDPToken {})?,
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}),
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})?,
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})],
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log: vec![],
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})
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}
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Initializes a new pool contract. Updates data storage as defined with config.rs, and initializes a new DP token contract linked to this pool contract.
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pub fn handle<S: Storage, A: Api, Q: Querier>(
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deps: &mut Extern<S, A, Q>,
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env: Env,
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msg: HandleMsg,
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) -> StdResult<HandleResponse> {
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match msg {
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HandleMsg::Receive(msg) => CoreHandler::receive(deps, env, msg),
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HandleMsg::Deposit {} => CoreHandler::deposit(deps, env),
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HandleMsg::ClaimReward {} => CoreHandler::claim_reward(deps, env),
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HandleMsg::RegisterDPToken {} => CoreHandler::register_dp_token(deps, env),
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}
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}
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​
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Defines HandleMsg endpoints. Calls the following functions per HandleMsg:
  • Receive(msg) : calls receive(deps, env, msg) defined under handler_exec.rs.
  • Deposit {} : calls deposit(deps, env) defined under handler_exec.rs.
  • ClaimReward {} : calls claim_reward(deps, env) defined under handler_exec.rs.
  • [INTERNAL] RegisterDPToken {} : calls register_dp_token(deps, env) defined under handler_exec.rs.
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pub fn query<S: Storage, A: Api, Q: Querier>(
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deps: &Extern<S, A, Q>,
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msg: QueryMsg,
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) -> StdResult<Binary> {
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match msg {
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QueryMsg::DepositAmountOf { owner } => QueryHandler::deposit_amount(deps, owner), // dp_token.balanceOf(msg.sender)
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QueryMsg::TotalDepositAmount {} => QueryHandler::total_deposit_amount(deps), // dp_token.totalSupply()
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QueryMsg::Config {} => QueryHandler::config(deps), // config
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QueryMsg::ClaimableReward {} => QueryHandler::claimable_reward(deps), // config.strategy.reward()
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}
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}
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​
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Defines QueryMsg endpoints. Calls the following functions per QueryMsg:
  • DepositAmountOf { owner } : calls deposit_amount(deps, owner) defined under handler_query.rs; returns the current DP token balance of the sender of this message.
  • TotalDepositAmount {} : calls total_deposit_amount(deps) defined under handler_query.rs; returns the total DP token balanced linked to this pool contract.
  • Config {} : calls config(deps) defined under handler/query.rs; returns the following:
    • beneficiary: returns the current beneficiary address set for this pool contract.
    • moneymarket: returns the Anchor money market contract set for this pool contract to call for deposit_stable and redeem_stable messages. For further information regarding logic of the Anchor money market, please refer to Anchor Protocol's official documentation.
    • stable_denom: returns the current Terra stablecoin denomination that the underlying Anchor money market contract accepts.
    • anchor_token: returns the aToken contract address that the underlying Anchor money market contract returns on deposits.
    • dp_token: returns the DP token contract address minted by this pool contract on new deposits.
  • GetClaimableReward {} : calls claimable_reward(deps) defined under handler_query.rs; returns all claimable UST rewards for all UST deposits held by this pool.
​

handler/core.rs

Defines core contract execution logic. Functions are as follows:
  • receive: defines a CW-20 token contract receive hook, which is executed when a Pylon DP token is sent to this Pylon pool.
  • deposit: deposits UST to this Pylon pool, deposits them to Anchor, and mints Pylon DP tokens back to the depositor.
  • redeem: consecutively called on a CW-20 receive call. Burns received DP tokens, retrieves equivalent amounts of UST from Anchor, and returns principal UST deposits excluding any interest generated.
  • claim_reward: claims any remaining interest remaining in the pool, and sends them over to the beneficiary address. Interest is calculated as (total_aust_amount * exchange_rate) - (total_dp_balance)
  • register_dp_token: registers a DP token contract controlled by this Pylon deposit pool for new DP token mints/burns on deposits/redemptions.
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pub fn receive<S: Storage, A: Api, Q: Querier>(
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deps: &Extern<S, A, Q>,
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env: Env,
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cw20_msg: Cw20ReceiveMsg,
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) -> StdResult<HandleResponse> {
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let sender = env.message.sender.clone();
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if let Some(msg) = cw20_msg.msg {
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match from_binary(&msg)? {
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Cw20HookMsg::Redeem {} => {
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// only asset contract can execute this message
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let config: config::Config = config::read(&deps.storage)?;
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if deps.api.canonical_address(&sender)? != config.dp_token {
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return Err(StdError::unauthorized());
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}
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​
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redeem(deps, env, cw20_msg.sender, cw20_msg.amount)
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}
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}
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} else {
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Err(StdError::generic_err(
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"Invalid request: \"redeem\" message not included in request",
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))
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}
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}
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​
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If a CW-20 transfer to this contract includes a Redeem {} Cw20HookMsg:
  • checks if the sender of this HookMsg is the registered DP token address (i.e. not any other token contract address being sent to this pool) - return unauthorized() error if not, else continue
  • if passed, call redeem(deps, _env, cw20_msg.sender, cw20_msg.amount)
If a Redeem {} message is not included with this function call, return an invalid_request error.
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pub fn deposit<S: Storage, A: Api, Q: Querier>(
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deps: &Extern<S, A, Q>,
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env: Env,
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) -> StdResult<HandleResponse> {
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let config = config::read(&deps.storage)?;
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​
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// check deposit
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let received: Uint256 = env
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.message
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.sent_funds
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.iter()
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.find(|c| c.denom == config.stable_denom)
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.map(|c| Uint256::from(c.amount))
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.unwrap_or_else(Uint256::zero);
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​
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if received.is_zero() {
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return Err(StdError::generic_err(format!(
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"Pool: insufficient token amount {}",
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config.stable_denom,
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)));
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}
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​
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let deposit_amount = deduct_tax(
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deps,
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Coin {
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denom: config.stable_denom.clone(),
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amount: received.into(),
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},
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)?
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.amount;
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​
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Ok(HandleResponse {
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messages: [
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querier::feeder::update_msg(deps, &config.exchange_rate_feeder, &config.dp_token)?,
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querier::anchor::deposit_stable_msg(
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deps,
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&config.moneymarket,
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&config.stable_denom,
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deposit_amount,
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)?,
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vec![CosmosMsg::Wasm(WasmMsg::Execute {
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contract_addr: deps.api.human_address(&config.dp_token)?,
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msg: to_binary(&Cw20HandleMsg::Mint {
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recipient: env.message.sender.clone(),
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amount: deposit_amount,
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})?,
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send: vec![],
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})],
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]
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.concat(),
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log: vec![
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log("action", "deposit"),
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log("sender", env.message.sender),
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log("amount", deposit_amount.to_string()),
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],
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data: None,
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})
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}
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​
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Sending native Terra stablecoins (UST) with this MsgExecuteContract call:
  • Check how much deposits have been made to this pool contract for stable_denom.
    • If there are no deposits, return a generic_err.
  • Issue a HandleResponse issuing the following messages:
    • call deposit_stable from the Anchor money market contract for deposit_amount units of stable_denom(e.g. 100 UST). aUST will be returned from the Anchor money market contract to this pool contract.
    • issue another MsgExecuteContract call that mints deposit_amount units of Pylon DP tokens for this particular pool to the caller.
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pub fn redeem<S: Storage, A: Api, Q: Querier>(
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deps: &Extern<S, A, Q>,
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env: Env,
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sender: HumanAddr,
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amount: Uint128,
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) -> StdResult<HandleResponse> {
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let config = config::read(&deps.storage)?;
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​
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let (market_redeem_amount, pool_redeem_amount, _) =
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querier::pool::calculate_return_amount(deps, &config, Uint256::from(amount))?;
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​
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Ok(HandleResponse {
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messages: [
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querier::feeder::update_msg(deps, &config.exchange_rate_feeder, &config.dp_token)?,
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vec![CosmosMsg::Wasm(WasmMsg::Execute {
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contract_addr: deps.api.human_address(&config.dp_token)?,
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msg: to_binary(&Cw20HandleMsg::Burn { amount })?,
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send: vec![],
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})],
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querier::anchor::redeem_stable_msg(
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deps,
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&config.moneymarket,
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&config.atoken,
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market_redeem_amount.into(),
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)?,
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vec![CosmosMsg::Bank(BankMsg::Send {
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from_address: env.contract.address,
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to_address: sender,
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amount: vec![pool_redeem_amount.clone()],
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})],
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]
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.concat(),
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log: vec![
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log("action", "redeem"),
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log("sender", env.message.sender),
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log("amount", pool_redeem_amount.amount),
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],
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data: None,
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})
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}
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​
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When a Redeem {} Cw20HookMsg is called:
  • Query the current epoch_state from the Anchor money market.
  • Calculate how much aUST needs to be redeemed back to UST to maintain principle: dp_token_balance / epoch_state.exchange_rate
  • Calculate how much Terra tax is charged during redemptions. As tax is charged for every Terra stablecoin MsgSends on the Terra blockchain, deduct_tax should be called twice, as there are two cases when Terra tax is charged for UST transfers during redemptions:
    • when UST is transferred from the Anchor money market to this Pylon pool contract
    • when UST is transferred from this Pylon pool contract to the user's wallet
  • Issue a HandleResponse containing the following messages:
    • burn amount units of DP tokens for this Pylon pool.
    • redeem market_redeem_amount aUST (calculated as dp_token_balance / epoch_state.exchange_rate) for pool_redeem_amount UST.
    • MsgSends pool_redeem_amount back to the caller of this contract
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pub fn claim_reward<S: Storage, A: Api, Q: Querier>(
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deps: &Extern<S, A, Q>,
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env: Env,
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) -> StdResult<HandleResponse> {
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// calculate (total_aust_amount * exchange_rate) - (total_dp_balance)
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let config = config::read(&deps.storage)?;
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if config.beneficiary != deps.api.canonical_address(&env.message.sender)? {
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return Err(StdError::unauthorized());
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}
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​
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let (reward_amount, fee_amount) =
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querier::pool::calculate_reward_amount(deps, &config, Option::from(env.block.time))?;
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let (market_redeem_amount, _, _) =
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querier::pool::calculate_return_amount(deps, &config, reward_amount.add(fee_amount))?;
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let (_, beneficiary_redeem_amount, _) =
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querier::pool::calculate_return_amount(deps, &config, reward_amount)?;
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let (_, collector_redeem_amount, _) =
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querier::pool::calculate_return_amount(deps, &config, fee_amount)?;
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​
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Ok(HandleResponse {
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messages: [
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querier::feeder::update_msg(deps, &config.exchange_rate_feeder, &config.dp_token)?,
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querier::anchor::redeem_stable_msg(
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deps,
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&config.moneymarket,
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&config.atoken,
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market_redeem_amount.into(),
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)?,
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vec![
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CosmosMsg::Bank(BankMsg::Send {
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from_address: env.contract.address.clone(),
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to_address: deps.api.human_address(&config.beneficiary)?,
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amount: vec![beneficiary_redeem_amount.clone()],
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}),
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CosmosMsg::Bank(BankMsg::Send {
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from_address: env.contract.address.clone(),
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to_address: deps.api.human_address(&config.fee_collector)?,
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amount: vec![collector_redeem_amount.clone()],
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}),
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],
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]
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.concat(),
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log: vec![
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log("action", "claim_reward"),
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log("sender", env.message.sender),
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log("amount", beneficiary_redeem_amount.amount),
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log("fee", collector_redeem_amount.amount),
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],
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data: None,
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})
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}
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​
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On a ClaimReward {} HandleMsg call:
  • calculate how much aUST should be redeemed: (total_aust_amount * exchange_rate) - (total_dp_balance)
  • apply a virtual exchange rate queryable from the Pylon Exchange Rate contract. This effectively re-calculates how much UST should be claimed excluding MINE token buybacks, which is sent to the Collector contract.
  • calculates how much UST should be redeemed for:
    • market_redeem_amount : amount of aUST for redemptions before Terra blockchain tax for both beneficiary and collector. returns Uint256.
    • beneficiary_redeem_amount : amount of aUST for redemptions after Terra blockchain tax for beneficiary. returns a Coin object.
    • collector_redeem_amount : amount of aUST for redemptions after Terra blockchain tax for collector, sent to the Collector contract for buybacks. returns a Coin object.
  • Issue a HandleResponse that includes the following messages:
    • update virtual exchange rate
    • redeem market_redeem_amount aUST from Anchor
    • send beneficiary_redeem_amount to beneficiary account
    • send collector_redeem_amount to Collector contract
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Last modified 11mo ago
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Contents
config.rs
contract.rs
handler/core.rs