scilla_version 0 (***************************************************) (* Associated library *) (***************************************************) import BoolUtils ListUtils IntUtils library FungibleToken let one_msg = fun (msg : Message) => let nil_msg = Nil {Message} in Cons {Message} msg nil_msg let two_msgs = fun (msg1 : Message) => fun (msg2 : Message) => let msgs_tmp = one_msg msg2 in Cons {Message} msg1 msgs_tmp (* Error events *) type Error = | CodeNotOwner | CodeIsSender | CodeNotApprovedOperator | CodeNotApprovedSpender | CodeNoBalance | CodeInsufficientFunds | CodeInsufficientAllowanceOrFunds let make_error = fun (result : Error) => let result_code = match result with | CodeNotOwner => Int32 -1 | CodeIsSender => Int32 -2 | CodeNotApprovedOperator => Int32 -3 | CodeNotApprovedSpender => Int32 -4 | CodeNoBalance => Int32 -5 | CodeInsufficientFunds => Int32 -6 | CodeInsufficientAllowanceOrFunds => Int32 -7 end in { _exception : "Error"; code : result_code } let zero = Uint128 0 (* Dummy user-defined ADT *) type Unit = | Unit let min_int = fun (a : Uint128) => fun (b : Uint128) => let min = builtin lt a b in match min with | True => a | False => b end (* A util function to test equality *) let f_eq = fun (a : ByStr20) => fun (b : ByStr20) => builtin eq a b (* Instantiate a type function to test membership in a list *) let is_default_operator = @list_mem ByStr20 let get_val = fun (some_val: Option Uint128) => match some_val with | Some val => val | None => zero end (***************************************************) (* The contract definition *) (***************************************************) contract FungibleToken ( contract_owner: ByStr20, name : String, symbol: String, decimals: Uint32, default_operators : List ByStr20, init_supply : Uint128 ) (* Mutable fields *) field total_supply : Uint128 = init_supply field balances: Map ByStr20 Uint128 = let emp_map = Emp ByStr20 Uint128 in builtin put emp_map contract_owner init_supply field operators: Map ByStr20 (Map ByStr20 Unit) = Emp ByStr20 (Map ByStr20 Unit) field revoked_default_operators : Map ByStr20 (Map ByStr20 Unit) = Emp ByStr20 (Map ByStr20 Unit) field allowances: Map ByStr20 (Map ByStr20 Uint128) = Emp ByStr20 (Map ByStr20 Uint128) (**************************************) (* Procedures *) (**************************************) procedure ThrowError(err : Error) e = make_error err; throw e end procedure IsOwner(address: ByStr20) is_owner = builtin eq contract_owner address; match is_owner with | True => | False => err = CodeNotOwner; ThrowError err end end procedure IsNotSender(address: ByStr20) is_sender = builtin eq _sender address; match is_sender with | True => err = CodeIsSender; ThrowError err | False => end end procedure IsApprovedOperator(token_owner: ByStr20, operator: ByStr20) is_operator_approved <- exists operators[token_owner][operator]; is_default_operator = is_default_operator f_eq operator default_operators; is_revoked_operator <- exists revoked_default_operators[token_owner][operator]; is_default_operator_approved = let is_not_revoked_operator = negb is_revoked_operator in andb is_not_revoked_operator is_default_operator; is_approved = orb is_operator_approved is_default_operator_approved; match is_approved with | True => | False => err = CodeNotApprovedOperator; ThrowError err end end procedure AuthorizedMint(recipient: ByStr20, amount: Uint128) some_bal <- balances[recipient]; bal = get_val some_bal; new_balance = builtin add amount bal; balances[recipient] := new_balance; current_total_supply <- total_supply; new_total_supply = builtin add current_total_supply amount; total_supply := new_total_supply; e = {_eventname: "Minted"; minter: _sender; recipient: recipient; amount: amount}; event e end procedure AuthorizedBurnIfSufficientBalance(from: ByStr20, amount: Uint128) get_bal <- balances[from]; match get_bal with | Some bal => can_burn = uint128_le amount bal; match can_burn with | True => (* Subtract amount from from *) new_balance = builtin sub bal amount; balances[from] := new_balance; current_total_supply <- total_supply; new_total_supply = builtin sub current_total_supply amount; total_supply := new_total_supply; e = {_eventname: "Burnt"; burner: _sender; burn_account: from; amount: amount}; event e | False => err = CodeInsufficientFunds; ThrowError err end | None => err = CodeNoBalance; ThrowError err end end procedure AuthorizedMoveIfSufficientBalance(from: ByStr20, to: ByStr20, amount: Uint128) get_from_bal <- balances[from]; match get_from_bal with | Some bal => can_do = uint128_le amount bal; match can_do with | True => (* Subtract amount from from and add it to to address *) new_from_bal = builtin sub bal amount; balances[from] := new_from_bal; (* Adds amount to to address *) get_to_bal <- balances[to]; new_to_bal = match get_to_bal with | Some bal => builtin add bal amount | None => amount end; balances[to] := new_to_bal | False => (* Balance not sufficient *) err = CodeInsufficientFunds; ThrowError err end | None => err = CodeNoBalance; ThrowError err end end (***************************************) (* Transitions *) (***************************************) (* Getter transitions *) (* @dev: Check if an address is an operator or default operator of a token_owner. Throw if not. *) (* @param operator: Address of a potential operator. *) (* @param token_owner: Address of a token_owner. *) transition IsOperatorFor(token_owner: ByStr20, operator: ByStr20) IsApprovedOperator token_owner operator; msg_to_sender = {_tag : "IsOperatorForCallBack"; _recipient : _sender; _amount : zero; token_owner: token_owner; operator : operator}; msgs = one_msg msg_to_sender; send msgs end (* Optional transitions *) (* @dev: Mint new tokens. Only contract_owner can mint. *) (* @param recipient: Address of the recipient whose balance is to increase. *) (* @param amount: Number of tokens to be minted. *) transition Mint(recipient: ByStr20, amount: Uint128) IsOwner _sender; AuthorizedMint recipient amount; (* Prevent sending to a contract address that does not support transfers of token *) msg_to_recipient = {_tag : "RecipientAcceptMint"; _recipient : recipient; _amount : zero; minter : _sender; recipient : recipient; amount : amount}; msg_to_sender = {_tag : "MintSuccessCallBack"; _recipient : _sender; _amount : zero; minter : _sender; recipient : recipient; amount : amount}; msgs = two_msgs msg_to_recipient msg_to_sender; send msgs end (* @dev: Burn existing tokens. Only contract_owner can burn. *) (* @param burn_account: Address of the token_owner whose balance is to decrease. *) (* @param amount: Number of tokens to be burned. *) transition Burn(burn_account: ByStr20, amount: Uint128) IsOwner _sender; AuthorizedBurnIfSufficientBalance burn_account amount; msg_to_sender = {_tag : "BurnSuccessCallBack"; _recipient : _sender; _amount : zero; burner : _sender; burn_account : burn_account; amount : amount}; msgs = one_msg msg_to_sender; send msgs end (* Compulsory interface transitions *) (* @dev: Make an address an operator of the caller. *) (* @param operator: Address to be authorize as operator or *) (* Re-authorize as default_operator. Cannot be calling address. *) transition AuthorizeOperator(operator: ByStr20) IsNotSender operator; (* Re-authorize default_operator if exists *) delete revoked_default_operators[_sender][operator]; (* Authorize new operator if not default_operator *) verdad = Unit; operators[_sender][operator] := verdad; e = {_eventname : "AuthorizeOperatorSuccess"; authorizer : _sender; authorized_operator : operator}; event e end (* @dev: Revoke an address from being an operator or default_operator of the caller. *) (* @param operator: Address to be removed as operator or default_operator. *) transition RevokeOperator(operator: ByStr20) IsApprovedOperator _sender operator; (* Remove operator if exists *) delete operators[_sender][operator]; (* Revoke default_operator if exists *) verdad = Unit; revoked_default_operators[_sender][operator] := verdad; e = {_eventname : "RevokeOperatorSuccess"; revoker : _sender; revoked_operator : operator}; event e end (* @dev: Increase the allowance of an approved_spender over the caller tokens. Only token_owner allowed to invoke. *) (* param spender: Address of the designated approved_spender. *) (* param amount: Number of tokens to be increased as allowance for the approved_spender. *) transition IncreaseAllowance(spender: ByStr20, amount: Uint128) IsNotSender spender; some_current_allowance <- allowances[_sender][spender]; current_allowance = get_val some_current_allowance; new_allowance = builtin add current_allowance amount; allowances[_sender][spender] := new_allowance; e = {_eventname : "IncreasedAllowance"; token_owner : _sender; spender: spender; new_allowance : new_allowance}; event e end (* @dev: Decrease the allowance of an approved_spender over the caller tokens. Only token_owner allowed to invoke. *) (* param spender: Address of the designated approved_spender. *) (* param amount: Number of tokens to be decreased as allowance for the approved_spender. *) transition DecreaseAllowance(spender: ByStr20, amount: Uint128) IsNotSender spender; some_current_allowance <- allowances[_sender][spender]; current_allowance = get_val some_current_allowance; new_allowance = let amount_le_allowance = uint128_le amount current_allowance in match amount_le_allowance with | True => builtin sub current_allowance amount | False => zero end; allowances[_sender][spender] := new_allowance; e = {_eventname : "DecreasedAllowance"; token_owner : _sender; spender: spender; new_allowance : new_allowance}; event e end (* @dev: Moves an amount tokens from _sender to the recipient. Used by token_owner. *) (* @dev: Balance of recipient will increase. Balance of _sender will decrease. *) (* @param to: Address of the recipient whose balance is increased. *) (* @param amount: Amount of tokens to be sent. *) transition Transfer(to: ByStr20, amount: Uint128) AuthorizedMoveIfSufficientBalance _sender to amount; e = {_eventname : "TransferSuccess"; sender : _sender; recipient : to; amount : amount}; event e; (* Prevent sending to a contract address that does not support transfers of token *) msg_to_recipient = {_tag : "RecipientAcceptTransfer"; _recipient : to; _amount : zero; sender : _sender; recipient : to; amount : amount}; msg_to_sender = {_tag : "TransferSuccessCallBack"; _recipient : _sender; _amount : zero; sender : _sender; recipient : to; amount : amount}; msgs = two_msgs msg_to_recipient msg_to_sender; send msgs end (* @dev: Moves amount tokens from token_owner to recipient. _sender must be an operator of token_owner. *) (* @dev: Balance of recipient will increase. Balance of token_owner will decrease. *) (* @param from: Address of the token_owner whose balance is decreased. *) (* @param to: Address of the recipient whose balance is increased. *) (* @param amount: Amount of tokens to be sent. *) transition OperatorSend(from: ByStr20, to: ByStr20, amount: Uint128) IsApprovedOperator from _sender; AuthorizedMoveIfSufficientBalance from to amount; e = {_eventname : "OperatorSendSuccess"; initiator : _sender; sender : from; recipient : to; amount : amount}; event e; (* Prevent sending to a contract address that does not support transfers of token *) msg_to_recipient = {_tag : "RecipientAcceptOperatorSend"; _recipient : to; _amount : zero; initiator : _sender; sender : from; recipient : to; amount : amount}; msg_to_sender = {_tag : "OperatorSendSuccessCallBack"; _recipient : _sender; _amount : zero; initiator : _sender; sender : from; recipient : to; amount : amount}; msgs = two_msgs msg_to_recipient msg_to_sender; send msgs end (* @dev: Move a given amount of tokens from one address to another using the allowance mechanism. The caller must be an approved_spender. *) (* @dev: Balance of recipient will increase. Balance of token_owner will decrease. *) (* @param from: Address of the token_owner whose balance is decreased. *) (* @param to: Address of the recipient whose balance is increased. *) (* @param amount: Amount of tokens to be transferred. *) transition TransferFrom(from: ByStr20, to: ByStr20, amount: Uint128) get_bal <- balances[from]; match get_bal with | Some bal => get_spender_allowed <- allowances[from][_sender]; match get_spender_allowed with | Some allowed => min = min_int bal allowed; can_do = uint128_le amount min; match can_do with | True => AuthorizedMoveIfSufficientBalance from to amount; e = {_eventname : "TransferFromSuccess"; initiator : _sender; sender : from; recipient : to; amount : amount}; event e; new_allowed = builtin sub allowed amount; allowances[from][_sender] := new_allowed; (* Prevent sending to a contract address that does not support transfers of token *) msg_to_recipient = {_tag : "RecipientAcceptTransferFrom"; _recipient : to; _amount : zero; initiator : _sender; sender : from; recipient : to; amount : amount}; msg_to_sender = {_tag : "TransferFromSuccessCallBack"; _recipient : _sender; _amount : zero; initiator : _sender; sender : from; recipient : to; amount : amount}; msgs = two_msgs msg_to_recipient msg_to_sender; send msgs | False => err = CodeInsufficientAllowanceOrFunds; ThrowError err end | None => err = CodeNotApprovedSpender; ThrowError err end | None => err = CodeNoBalance; ThrowError err end end

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