// SPDX-License-Identifier: GPL-3.0 // // :+#####%%%%%%%%%%%%%%+ // .-*@@@%+.:+%@@@@@%%#***%@@%= // :=*%@@@#=. :#@@% *@@@%= // .-+*%@%*-.:+%@@@@@@+. -*+: .=#. :%@@@%- // :=*@@@@%%@@@@@@@@@%@@@- .=#@@@%@%= =@@@@#. // -=+#%@@%#*=:. :%@@@@%. -*@@#*@@@@@@@#=:- *@@@@+ // =@@%=:. :=: *@@@@@%#- =%*%@@@@#+-. =+ :%@@@%- // -@@%. .+@@@ =+=-. @@#- +@@@%- =@@@@%: // :@@@. .+@@#%: : .=*=-::.-%@@@+*@@= +@@@@#. // %@@: +@%%* =%@@@@@@@@@@@#. .*@%- +@@@@*. // #@@= .+@@@@%:=*@@@@@- :%@%: .*@@@@+ // *@@* +@@@#-@@%-:%@@* +@@#. :%@@@@- // -@@% .:-=++*##%%%@@@@@@@@@@@@*. :@+.@@@%: .#@@+ =@@@@#: // .@@@*-+*#%%%@@@@@@@@@@@@@@@@%%#**@@%@@@. *@=*@@# :#@%= .#@@@@#- // -%@@@@@@@@@@@@@@@*+==-:-@@@= *@# .#@*-=*@@@@%= -%@@@* =@@@@@%- // -+%@@@#. %@%%= -@@:+@: -@@* *@@*-:: -%@@%=. .*@@@@@# // *@@@* +@* *@@##@@- #@*@@+ -@@= . :+@@@#: .-+@@@%+- // +@@@%*@@:..=@@@@* .@@@* .#@#. .=+- .=%@@@*. :+#@@@@*=: // =@@@@%@@@@@@@@@@@@@@@@@@@@@@%- :+#*. :*@@@%=. .=#@@@@%+: // .%@@= ..... .=#@@+. .#@@@*: -*%@@@@%+. // +@@#+===---:::... .=%@@*- +@@@+. -*@@@@@%+. // -@@@@@@@@@@@@@@@@@@@@@@%@@@@= -@@@+ -#@@@@@#=. // ..:::---===+++***###%%%@@@#- .#@@+ -*@@@@@#=. // @@@@@@+. +@@*. .+@@@@@%=. // -@@@@@= =@@%: -#@@@@%+. // +@@@@@. =@@@= .+@@@@@*: // #@@@@#:%@@#. :*@@@@#- // @@@@@%@@@= :#@@@@+. // :@@@@@@@#.:#@@@%- // +@@@@@@-.*@@@*: // #@@@@#.=@@@+. // @@@@+-%@%= // :@@@#%@%= // +@@@@%- // :#%%= // /** * NOTICE * * The T-REX software is licensed under a proprietary license or the GPL v.3. * If you choose to receive it under the GPL v.3 license, the following applies: * T-REX is a suite of smart contracts implementing the ERC-3643 standard and * developed by Tokeny to manage and transfer financial assets on EVM blockchains * * Copyright (C) 2023, Tokeny sàrl. * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see . */ pragma solidity 0.8.17; import "../BasicCompliance.sol"; /** * this feature allows to require the pre-validation of a transfer before allowing it to be executed * This feature is also known as "conditional transfers" feature */ abstract contract ApproveTransfer is BasicCompliance { /// Mapping of transfersApproved mapping(bytes32 => bool) private _transfersApproved; /** * this event is emitted when a transfer is approved * the event is emitted by the `approveTransfer` and `approveAndTransfer` functions * `_from` is the address of the transfer sender * `_to` is the address of the transfer receiver * `_amount` is the amount of tokens that `_from` is allowed to send to `_to` * note that the approved transfer has to be exactly of the approved amount `_amount` * `_token` is the address of the token that is allowed to be transferred */ event TransferApproved(address _from, address _to, uint _amount, address _token); /** * this event is emitted when a transfer approval is removed * the event is emitted by the `removeApproval` function * `_from` is the address of the transfer sender * `_to` is the address of the transfer receiver * `_amount` is the amount of tokens that `_from` was allowed to send to `_to` * `_token` is the address of the token that was allowed to be transferred */ event ApprovalRemoved(address _from, address _to, uint _amount, address _token); /** * @dev removes approval on a transfer previously approved * requires the transfer to be previously approved * once a transfer approval is removed, the sender is not allowed to execute it anymore * @param _from the address of the transfer sender * @param _to the address of the transfer receiver * @param _amount the amount of tokens that `_from` was allowed to send to `_to` * Only Admin can call this function, i.e. owner of compliance contract OR token agent * emits an `ApprovalRemoved` event */ function removeApproval(address _from, address _to, uint _amount) external onlyAdmin { bytes32 transferId = _calculateTransferID (_from, _to, _amount, address(tokenBound)); require(_transfersApproved[transferId], "transfer not approved yet"); _transfersApproved[transferId] = false; emit ApprovalRemoved(_from, _to, _amount, address(tokenBound)); } /** * @dev Approves a transfer and execute it immediately * As the function calls `transferFrom` on the token contract, the compliance contract, which is de facto sender of * that function call has to be allowed to make such a call, i.e. the allowance should be >= `_amount` with * Compliance contract address being the spender address * @param _from the address of the transfer sender * @param _to the address of the transfer receiver * @param _amount the amount of tokens that `_from` would send to `_to` * Only Admin can call this function, i.e. owner of compliance contract OR token agent * emits a `TransferApproved` event, an `ApprovalRemoved` event and a `Transfer` event */ function approveAndTransfer(address _from, address _to, uint _amount) external { approveTransfer(_from, _to, _amount); tokenBound.transferFrom(_from, _to, _amount); } /** * @dev Approves a transfer * once a transfer is approved, the sender is allowed to execute it * @param _from the address of the transfer sender * @param _to the address of the transfer receiver * @param _amount the amount of tokens that `_from` would send to `_to` * Only Admin can call this function, i.e. owner of compliance contract OR token agent * emits a `TransferApproved` event */ function approveTransfer(address _from, address _to, uint _amount) public onlyAdmin { bytes32 transferId = _calculateTransferID (_from, _to, _amount, address(tokenBound)); require(!_transfersApproved[transferId], "transfer already approved"); _transfersApproved[transferId] = true; emit TransferApproved(_from, _to, _amount, address(tokenBound)); } /** * @dev check on the compliance status of a transaction. * If the check returns TRUE, the transfer is allowed to be executed, if the check returns FALSE, the compliance * feature will block the transfer execution * The check will verify if the transferID corresponding to the parameters of the transfer corresponds to a * pre-approved transfer or not, and will return TRUE or FALSE according to the approval status of the said transfer * If `_from` is a token agent, the transfer will pass whatever the approval status may be as agents bypass this * compliance feature. * @param _from the address of the transfer sender * @param _to the address of the transfer receiver * @param _value the amount of tokens that `_from` would send to `_to` */ function complianceCheckOnApproveTransfer(address _from, address _to, uint256 _value) public view returns (bool) { if (!isTokenAgent(_from)) { bytes32 transferId = _calculateTransferID (_from, _to, _value, address(tokenBound)); if (!_transfersApproved[transferId]){ return false; } } return true; } /** * @dev state update of the compliance feature post-transfer. * calls the `_transferProcessed` function to update approval status post-transfer * @param _from the address of the transfer sender * @param _to the address of the transfer receiver * @param _value the amount of tokens that `_from` sent to `_to` * internal function, can be called only from the functions of the Compliance smart contract */ function _transferActionOnApproveTransfer(address _from, address _to, uint256 _value) internal { _transferProcessed(_from, _to, _value); } /** * @dev state update of the compliance feature post-minting. * this compliance feature doesn't require state update post-minting * @param _to the address of the minting beneficiary * @param _value the amount of tokens minted on `_to` wallet * internal function, can be called only from the functions of the Compliance smart contract */ // solhint-disable-next-line no-empty-blocks function _creationActionOnApproveTransfer(address _to, uint256 _value) internal {} /** * @dev state update of the compliance feature post-burning. * this compliance feature doesn't require state update post-burning * @param _from the wallet address on which tokens burnt * @param _value the amount of tokens burnt from `_from` wallet * internal function, can be called only from the functions of the Compliance smart contract */ // solhint-disable-next-line no-empty-blocks function _destructionActionOnApproveTransfer(address _from, uint256 _value) internal {} /** * @dev updates the approval status of a transfer post-execution * once an approved transfer is executed, the sender is not allowed to execute it anymore * @param _from the address of the transfer sender * @param _to the address of the transfer receiver * @param _amount the amount of tokens that `_from` was allowed to send to `_to` * internal function, can be called only from the functions of the Compliance smart contract * emits an `ApprovalRemoved` event if transfer was pre-approved, i.e. if function call was done by a regular * token holder, token agents bypassing the approval requirements */ function _transferProcessed(address _from, address _to, uint _amount) internal { bytes32 transferId = _calculateTransferID (_from, _to, _amount, address(tokenBound)); if (_transfersApproved[transferId]) { _transfersApproved[transferId] = false; emit ApprovalRemoved(_from, _to, _amount, address(tokenBound)); } } /** * @dev Calculates the ID of a transfer * transfer IDs are used to identify which transfer is approved and which is not at compliance contract level * @param _from the address of the transfer sender * @param _to the address of the transfer receiver * @param _amount the amount of tokens that `_from` would send to `_to` * @param _token the address of the token that would be transferred * returns the transferId of the transfer */ function _calculateTransferID ( address _from, address _to, uint _amount, address _token ) internal pure returns (bytes32){ bytes32 transferId = keccak256(abi.encode(_from, _to, _amount, _token)); return transferId; } }