Deposits and transfers

Deposits, balances, and transfers

Focus: one XELIS vault contract that credits deposits and lets users withdraw their own balance.

deposit_vault.slx


const BALANCES_KEY: string = "balances"
 
hook constructor() -> u64 {
    let storage: Storage = Storage::new()
    let balances: map<Address, u64> = {}
    storage.store(BALANCES_KEY, balances)
    return 0
}
 
fn balances() -> map<Address, u64> {
    let storage: Storage = Storage::new()
    return storage.load(BALANCES_KEY).unwrap_or({})
}
 
entry deposit_xel() -> u64 {
    let asset: Hash = get_xelis_asset()
    let amount: u64 = get_deposit_for_asset(asset).unwrap_or(0)
    require(amount > 0, "attach a XELIS deposit")
 
    let sender: Address = Transaction::current().unwrap().source()
    let ledger: map<Address, u64> = balances()
    let current: u64 = ledger.get(sender).unwrap_or(0)
    ledger.insert(sender, current + amount)
 
    let storage: Storage = Storage::new()
    storage.store(BALANCES_KEY, ledger)
    return current + amount
}
 
entry withdraw_xel(amount: u64) -> u64 {
    let asset: Hash = get_xelis_asset()
    let sender: Address = Transaction::current().unwrap().source()
    let ledger: map<Address, u64> = balances()
    let current: u64 = ledger.get(sender).unwrap_or(0)
 
    require(amount > 0 && current >= amount, "insufficient balance")
 
    let remaining: u64 = current - amount
    if remaining == 0 {
        ledger.shift_remove(sender)
    } else {
        ledger.insert(sender, remaining)
    }
 
    let storage: Storage = Storage::new()
    storage.store(BALANCES_KEY, ledger)
    require(transfer(sender, amount, asset), "transfer failed")
    return remaining
}

How it works

BALANCES_KEY stores a map<Address, u64> ledger in persistent storage.
constructor() initializes the ledger so later entries can load the same shape.
balances() is a small helper that loads the ledger and falls back to an empty map.
deposit_xel() reads the attached XELIS deposit with get_deposit_for_asset, credits the sender, stores the ledger, and returns the new balance.
withdraw_xel(amount) checks the sender’s recorded balance, updates or removes the ledger entry, transfers XELIS back with transfer, and returns the remaining balance.