Sov-ESDT-Safe

Whether an External Owned Account (EOA) like an user wallet or another smart contract the procedure is simple. An address will be able to perform a multi tokens transfer with various types of tokens:

• Fungible Tokens
• (Dynamic) Non-Fungible Tokens
• (Dynamic) Semi-Fungible Tokens
• (Dynamic) Meta ESDT Tokens

When making the deposit, the user specifies:

1. A destination address
2. TransferData if the execution contains a smart contract call, which contains gas, function and arguments

Sovereign Chain to Main Chain transfer flow

1. User deposits token to the Sov-ESDT-Safe smart contract.
2. Outgoing Operations are created at the end of the round.
3. Validators sign all the outgoing Operations.
4. Leader sends Operations to the Sovereign Bridge Service.
5. Sovereign Bridge Service sends the Operations to the Header-Verifier for registration and verification, and then to Mvx-ESDT-Safe for execution.
6. At the end of the execution success/fail, a confirmation event will be added which will be received in Sovereign through the observer and then the cross chain transfer will be completed.

Deposit Endpoint

    #[payable("*")]
    #[endpoint]
    fn deposit(
        &self,
        to: ManagedAddress,
        optional_transfer_data: OptionalValueTransferDataTuple<Self::Api>,
    )

As you can see both the Mvx-ESDT-Safe and Sov-ESDT-Safe smart contracts have the deposit endpoint. At a high level, the process is the same, depositing funds or calling other smart contracts. The main differences are when each payments is processed. Since the Sov-ESDT-Safe smart contract doesn't have the storage mapper for the native token, the payments won't be verified if they include any payment with the native token. The enabled checks are the same:

• If the token is whitelisted or not blacklisted, in that case the tokens can be transferred.
• If the fee is enabled, the smart contract assures that the fee is paid.
• If there are maximum 10 transfers in the transaction.

If the deposit also includes the optional_transfer_data parameter it will also have some extra checks regarding the cross-chain execution of endpoints:

• The gas limit must be under the specified limit.
• The endpoint that has to be executed is not blacklisted.

At the end of the deposit endpoint, all the extra tokens will be refunded to the caller and an event will be emitted since the bridging process is complete.

#[event("deposit")]
fn deposit_event(
    &self,
    #[indexed] dest_address: &ManagedAddress,
    #[indexed] tokens: &MultiValueEncoded<MultiValue3<TokenIdentifier, u64, EsdtTokenData>>,
    event_data: OperationData<Self::Api>,
)

This log event will emit the destination address and the tokens which will be transferred to the Sovereign Chain.

note

The source code for the endpoint can be found here.