Contract Name:
VotingEscrow
Contract Source Code:
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (governance/utils/IVotes.sol)
pragma solidity ^0.8.0;
/**
* @dev Common interface for {ERC20Votes}, {ERC721Votes}, and other {Votes}-enabled contracts.
*
* _Available since v4.5._
*/
interface IVotes {
/**
* @dev Emitted when an account changes their delegate.
*/
event DelegateChanged(address indexed delegator, address indexed fromDelegate, address indexed toDelegate);
/**
* @dev Emitted when a token transfer or delegate change results in changes to a delegate's number of votes.
*/
event DelegateVotesChanged(address indexed delegate, uint256 previousBalance, uint256 newBalance);
/**
* @dev Returns the current amount of votes that `account` has.
*/
function getVotes(address account) external view returns (uint256);
/**
* @dev Returns the amount of votes that `account` had at the end of a past block (`blockNumber`).
*/
function getPastVotes(address account, uint256 blockNumber) external view returns (uint256);
/**
* @dev Returns the total supply of votes available at the end of a past block (`blockNumber`).
*
* NOTE: This value is the sum of all available votes, which is not necessarily the sum of all delegated votes.
* Votes that have not been delegated are still part of total supply, even though they would not participate in a
* vote.
*/
function getPastTotalSupply(uint256 blockNumber) external view returns (uint256);
/**
* @dev Returns the delegate that `account` has chosen.
*/
function delegates(address account) external view returns (address);
/**
* @dev Delegates votes from the sender to `delegatee`.
*/
function delegate(address delegatee) external;
/**
* @dev Delegates votes from signer to `delegatee`.
*/
function delegateBySig(
address delegatee,
uint256 nonce,
uint256 expiry,
uint8 v,
bytes32 r,
bytes32 s
) external;
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (proxy/utils/Initializable.sol)
pragma solidity ^0.8.2;
import "../../utils/Address.sol";
/**
* @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
* behind a proxy. Since proxied contracts do not make use of a constructor, it's common to move constructor logic to an
* external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
* function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
*
* The initialization functions use a version number. Once a version number is used, it is consumed and cannot be
* reused. This mechanism prevents re-execution of each "step" but allows the creation of new initialization steps in
* case an upgrade adds a module that needs to be initialized.
*
* For example:
*
* [.hljs-theme-light.nopadding]
* ```
* contract MyToken is ERC20Upgradeable {
* function initialize() initializer public {
* __ERC20_init("MyToken", "MTK");
* }
* }
* contract MyTokenV2 is MyToken, ERC20PermitUpgradeable {
* function initializeV2() reinitializer(2) public {
* __ERC20Permit_init("MyToken");
* }
* }
* ```
*
* TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
* possible by providing the encoded function call as the `_data` argument to {ERC1967Proxy-constructor}.
*
* CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
* that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
*
* [CAUTION]
* ====
* Avoid leaving a contract uninitialized.
*
* An uninitialized contract can be taken over by an attacker. This applies to both a proxy and its implementation
* contract, which may impact the proxy. To prevent the implementation contract from being used, you should invoke
* the {_disableInitializers} function in the constructor to automatically lock it when it is deployed:
*
* [.hljs-theme-light.nopadding]
* ```
* /// @custom:oz-upgrades-unsafe-allow constructor
* constructor() {
* _disableInitializers();
* }
* ```
* ====
*/
abstract contract Initializable {
/**
* @dev Indicates that the contract has been initialized.
* @custom:oz-retyped-from bool
*/
uint8 private _initialized;
/**
* @dev Indicates that the contract is in the process of being initialized.
*/
bool private _initializing;
/**
* @dev Triggered when the contract has been initialized or reinitialized.
*/
event Initialized(uint8 version);
/**
* @dev A modifier that defines a protected initializer function that can be invoked at most once. In its scope,
* `onlyInitializing` functions can be used to initialize parent contracts.
*
* Similar to `reinitializer(1)`, except that functions marked with `initializer` can be nested in the context of a
* constructor.
*
* Emits an {Initialized} event.
*/
modifier initializer() {
bool isTopLevelCall = !_initializing;
require(
(isTopLevelCall && _initialized < 1) || (!Address.isContract(address(this)) && _initialized == 1),
"Initializable: contract is already initialized"
);
_initialized = 1;
if (isTopLevelCall) {
_initializing = true;
}
_;
if (isTopLevelCall) {
_initializing = false;
emit Initialized(1);
}
}
/**
* @dev A modifier that defines a protected reinitializer function that can be invoked at most once, and only if the
* contract hasn't been initialized to a greater version before. In its scope, `onlyInitializing` functions can be
* used to initialize parent contracts.
*
* A reinitializer may be used after the original initialization step. This is essential to configure modules that
* are added through upgrades and that require initialization.
*
* When `version` is 1, this modifier is similar to `initializer`, except that functions marked with `reinitializer`
* cannot be nested. If one is invoked in the context of another, execution will revert.
*
* Note that versions can jump in increments greater than 1; this implies that if multiple reinitializers coexist in
* a contract, executing them in the right order is up to the developer or operator.
*
* WARNING: setting the version to 255 will prevent any future reinitialization.
*
* Emits an {Initialized} event.
*/
modifier reinitializer(uint8 version) {
require(!_initializing && _initialized < version, "Initializable: contract is already initialized");
_initialized = version;
_initializing = true;
_;
_initializing = false;
emit Initialized(version);
}
/**
* @dev Modifier to protect an initialization function so that it can only be invoked by functions with the
* {initializer} and {reinitializer} modifiers, directly or indirectly.
*/
modifier onlyInitializing() {
require(_initializing, "Initializable: contract is not initializing");
_;
}
/**
* @dev Locks the contract, preventing any future reinitialization. This cannot be part of an initializer call.
* Calling this in the constructor of a contract will prevent that contract from being initialized or reinitialized
* to any version. It is recommended to use this to lock implementation contracts that are designed to be called
* through proxies.
*
* Emits an {Initialized} event the first time it is successfully executed.
*/
function _disableInitializers() internal virtual {
require(!_initializing, "Initializable: contract is initializing");
if (_initialized < type(uint8).max) {
_initialized = type(uint8).max;
emit Initialized(type(uint8).max);
}
}
/**
* @dev Internal function that returns the initialized version. Returns `_initialized`
*/
function _getInitializedVersion() internal view returns (uint8) {
return _initialized;
}
/**
* @dev Internal function that returns the initialized version. Returns `_initializing`
*/
function _isInitializing() internal view returns (bool) {
return _initializing;
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Metadata.sol)
pragma solidity ^0.8.0;
import "../IERC721.sol";
/**
* @title ERC-721 Non-Fungible Token Standard, optional metadata extension
* @dev See https://eips.ethereum.org/EIPS/eip-721
*/
interface IERC721Metadata is IERC721 {
/**
* @dev Returns the token collection name.
*/
function name() external view returns (string memory);
/**
* @dev Returns the token collection symbol.
*/
function symbol() external view returns (string memory);
/**
* @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
*/
function tokenURI(uint256 tokenId) external view returns (string memory);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (token/ERC721/IERC721.sol)
pragma solidity ^0.8.0;
import "../../utils/introspection/IERC165.sol";
/**
* @dev Required interface of an ERC721 compliant contract.
*/
interface IERC721 is IERC165 {
/**
* @dev Emitted when `tokenId` token is transferred from `from` to `to`.
*/
event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);
/**
* @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
*/
event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);
/**
* @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
*/
event ApprovalForAll(address indexed owner, address indexed operator, bool approved);
/**
* @dev Returns the number of tokens in ``owner``'s account.
*/
function balanceOf(address owner) external view returns (uint256 balance);
/**
* @dev Returns the owner of the `tokenId` token.
*
* Requirements:
*
* - `tokenId` must exist.
*/
function ownerOf(uint256 tokenId) external view returns (address owner);
/**
* @dev Safely transfers `tokenId` token from `from` to `to`.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `tokenId` token must exist and be owned by `from`.
* - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
*
* Emits a {Transfer} event.
*/
function safeTransferFrom(
address from,
address to,
uint256 tokenId,
bytes calldata data
) external;
/**
* @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
* are aware of the ERC721 protocol to prevent tokens from being forever locked.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `tokenId` token must exist and be owned by `from`.
* - If the caller is not `from`, it must have been allowed to move this token by either {approve} or {setApprovalForAll}.
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
*
* Emits a {Transfer} event.
*/
function safeTransferFrom(
address from,
address to,
uint256 tokenId
) external;
/**
* @dev Transfers `tokenId` token from `from` to `to`.
*
* WARNING: Note that the caller is responsible to confirm that the recipient is capable of receiving ERC721
* or else they may be permanently lost. Usage of {safeTransferFrom} prevents loss, though the caller must
* understand this adds an external call which potentially creates a reentrancy vulnerability.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `tokenId` token must be owned by `from`.
* - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
*
* Emits a {Transfer} event.
*/
function transferFrom(
address from,
address to,
uint256 tokenId
) external;
/**
* @dev Gives permission to `to` to transfer `tokenId` token to another account.
* The approval is cleared when the token is transferred.
*
* Only a single account can be approved at a time, so approving the zero address clears previous approvals.
*
* Requirements:
*
* - The caller must own the token or be an approved operator.
* - `tokenId` must exist.
*
* Emits an {Approval} event.
*/
function approve(address to, uint256 tokenId) external;
/**
* @dev Approve or remove `operator` as an operator for the caller.
* Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
*
* Requirements:
*
* - The `operator` cannot be the caller.
*
* Emits an {ApprovalForAll} event.
*/
function setApprovalForAll(address operator, bool _approved) external;
/**
* @dev Returns the account approved for `tokenId` token.
*
* Requirements:
*
* - `tokenId` must exist.
*/
function getApproved(uint256 tokenId) external view returns (address operator);
/**
* @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
*
* See {setApprovalForAll}
*/
function isApprovedForAll(address owner, address operator) external view returns (bool);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC721/IERC721Receiver.sol)
pragma solidity ^0.8.0;
/**
* @title ERC721 token receiver interface
* @dev Interface for any contract that wants to support safeTransfers
* from ERC721 asset contracts.
*/
interface IERC721Receiver {
/**
* @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
* by `operator` from `from`, this function is called.
*
* It must return its Solidity selector to confirm the token transfer.
* If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
*
* The selector can be obtained in Solidity with `IERC721Receiver.onERC721Received.selector`.
*/
function onERC721Received(
address operator,
address from,
uint256 tokenId,
bytes calldata data
) external returns (bytes4);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (utils/Address.sol)
pragma solidity ^0.8.1;
/**
* @dev Collection of functions related to the address type
*/
library Address {
/**
* @dev Returns true if `account` is a contract.
*
* [IMPORTANT]
* ====
* It is unsafe to assume that an address for which this function returns
* false is an externally-owned account (EOA) and not a contract.
*
* Among others, `isContract` will return false for the following
* types of addresses:
*
* - an externally-owned account
* - a contract in construction
* - an address where a contract will be created
* - an address where a contract lived, but was destroyed
* ====
*
* [IMPORTANT]
* ====
* You shouldn't rely on `isContract` to protect against flash loan attacks!
*
* Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
* like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
* constructor.
* ====
*/
function isContract(address account) internal view returns (bool) {
// This method relies on extcodesize/address.code.length, which returns 0
// for contracts in construction, since the code is only stored at the end
// of the constructor execution.
return account.code.length > 0;
}
/**
* @dev Replacement for Solidity's `transfer`: sends `amount` wei to
* `recipient`, forwarding all available gas and reverting on errors.
*
* https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
* of certain opcodes, possibly making contracts go over the 2300 gas limit
* imposed by `transfer`, making them unable to receive funds via
* `transfer`. {sendValue} removes this limitation.
*
* https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
*
* IMPORTANT: because control is transferred to `recipient`, care must be
* taken to not create reentrancy vulnerabilities. Consider using
* {ReentrancyGuard} or the
* https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
*/
function sendValue(address payable recipient, uint256 amount) internal {
require(address(this).balance >= amount, "Address: insufficient balance");
(bool success, ) = recipient.call{value: amount}("");
require(success, "Address: unable to send value, recipient may have reverted");
}
/**
* @dev Performs a Solidity function call using a low level `call`. A
* plain `call` is an unsafe replacement for a function call: use this
* function instead.
*
* If `target` reverts with a revert reason, it is bubbled up by this
* function (like regular Solidity function calls).
*
* Returns the raw returned data. To convert to the expected return value,
* use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
*
* Requirements:
*
* - `target` must be a contract.
* - calling `target` with `data` must not revert.
*
* _Available since v3.1._
*/
function functionCall(address target, bytes memory data) internal returns (bytes memory) {
return functionCallWithValue(target, data, 0, "Address: low-level call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
* `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCall(
address target,
bytes memory data,
string memory errorMessage
) internal returns (bytes memory) {
return functionCallWithValue(target, data, 0, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but also transferring `value` wei to `target`.
*
* Requirements:
*
* - the calling contract must have an ETH balance of at least `value`.
* - the called Solidity function must be `payable`.
*
* _Available since v3.1._
*/
function functionCallWithValue(
address target,
bytes memory data,
uint256 value
) internal returns (bytes memory) {
return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
}
/**
* @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
* with `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCallWithValue(
address target,
bytes memory data,
uint256 value,
string memory errorMessage
) internal returns (bytes memory) {
require(address(this).balance >= value, "Address: insufficient balance for call");
(bool success, bytes memory returndata) = target.call{value: value}(data);
return verifyCallResultFromTarget(target, success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
return functionStaticCall(target, data, "Address: low-level static call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(
address target,
bytes memory data,
string memory errorMessage
) internal view returns (bytes memory) {
(bool success, bytes memory returndata) = target.staticcall(data);
return verifyCallResultFromTarget(target, success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
return functionDelegateCall(target, data, "Address: low-level delegate call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(
address target,
bytes memory data,
string memory errorMessage
) internal returns (bytes memory) {
(bool success, bytes memory returndata) = target.delegatecall(data);
return verifyCallResultFromTarget(target, success, returndata, errorMessage);
}
/**
* @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
* the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
*
* _Available since v4.8._
*/
function verifyCallResultFromTarget(
address target,
bool success,
bytes memory returndata,
string memory errorMessage
) internal view returns (bytes memory) {
if (success) {
if (returndata.length == 0) {
// only check isContract if the call was successful and the return data is empty
// otherwise we already know that it was a contract
require(isContract(target), "Address: call to non-contract");
}
return returndata;
} else {
_revert(returndata, errorMessage);
}
}
/**
* @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
* revert reason or using the provided one.
*
* _Available since v4.3._
*/
function verifyCallResult(
bool success,
bytes memory returndata,
string memory errorMessage
) internal pure returns (bytes memory) {
if (success) {
return returndata;
} else {
_revert(returndata, errorMessage);
}
}
function _revert(bytes memory returndata, string memory errorMessage) private pure {
// Look for revert reason and bubble it up if present
if (returndata.length > 0) {
// The easiest way to bubble the revert reason is using memory via assembly
/// @solidity memory-safe-assembly
assembly {
let returndata_size := mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)
pragma solidity ^0.8.0;
/**
* @dev Interface of the ERC165 standard, as defined in the
* https://eips.ethereum.org/EIPS/eip-165[EIP].
*
* Implementers can declare support of contract interfaces, which can then be
* queried by others ({ERC165Checker}).
*
* For an implementation, see {ERC165}.
*/
interface IERC165 {
/**
* @dev Returns true if this contract implements the interface defined by
* `interfaceId`. See the corresponding
* https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
* to learn more about how these ids are created.
*
* This function call must use less than 30 000 gas.
*/
function supportsInterface(bytes4 interfaceId) external view returns (bool);
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.13;
interface IERC20 {
function totalSupply() external view returns (uint256);
function transfer(address recipient, uint amount) external returns (bool);
function decimals() external view returns (uint8);
function symbol() external view returns (string memory);
function balanceOf(address) external view returns (uint);
function transferFrom(address sender, address recipient, uint amount) external returns (bool);
function allowance(address owner, address spender) external view returns (uint);
function approve(address spender, uint value) external returns (bool);
event Transfer(address indexed from, address indexed to, uint value);
event Approval(address indexed owner, address indexed spender, uint value);
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.13;
interface IVeArtProxy {
function _tokenURI(uint _tokenId, uint _balanceOf, uint _locked_end, uint _value) external pure returns (string memory output);
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.13;
interface IVotingEscrow {
struct Point {
int128 bias;
int128 slope; // # -dweight / dt
uint256 ts;
uint256 blk; // block
}
struct LockedBalance {
int128 amount;
uint start;
uint end;
}
function create_lock_for(uint _value, uint _lock_duration, address _to) external returns (uint);
function locked(uint id) external view returns(LockedBalance memory);
function tokenOfOwnerByIndex(address _owner, uint _tokenIndex) external view returns (uint);
function token() external view returns (address);
function team() external returns (address);
function epoch() external view returns (uint);
function point_history(uint loc) external view returns (Point memory);
function user_point_history(uint tokenId, uint loc) external view returns (Point memory);
function user_point_epoch(uint tokenId) external view returns (uint);
function ownerOf(uint) external view returns (address);
function isApprovedOrOwner(address, uint) external view returns (bool);
function transferFrom(address, address, uint) external;
function voted(uint) external view returns (bool);
function attachments(uint) external view returns (uint);
function voting(uint tokenId) external;
function abstain(uint tokenId) external;
function attach(uint tokenId) external;
function detach(uint tokenId) external;
function checkpoint() external;
function deposit_for(uint tokenId, uint value) external;
function balanceOfAtNFT(uint _tokenId, uint _block) external view returns (uint);
function balanceOfNFT(uint _id) external view returns (uint);
function balanceOf(address _owner) external view returns (uint);
function totalSupply() external view returns (uint);
function supply() external view returns (uint);
function decimals() external view returns(uint8);
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.13;
library Constants {
uint256 internal constant EPOCH_LENGTH = 7 days;
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.13;
import {IERC721, IERC721Metadata} from "@openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol";
import {IVotes} from "@openzeppelin/contracts/governance/utils/IVotes.sol";
import {Initializable} from "@openzeppelin/contracts/proxy/utils/Initializable.sol";
import {IERC721Receiver} from "@openzeppelin/contracts/token/ERC721/IERC721Receiver.sol";
import {IERC20} from "./interfaces/IERC20.sol";
import {IVeArtProxy} from "./interfaces/IVeArtProxy.sol";
import {IVotingEscrow} from "./interfaces/IVotingEscrow.sol";
import {Constants} from "./libraries/Constants.sol";
/// @title Voting Escrow
/// @notice veNFT implementation that escrows ERC-20 tokens in the form of an ERC-721 NFT
/// @notice Votes have a weight depending on time, so that users are committed to the future of (whatever they are voting for)
/// @author Modified from Solidly (https://github.com/solidlyexchange/solidly/blob/master/contracts/ve.sol)
/// @author Modified from Curve (https://github.com/curvefi/curve-dao-contracts/blob/master/contracts/VotingEscrow.vy)
/// @author Modified from Nouns DAO (https://github.com/withtally/my-nft-dao-project/blob/main/contracts/ERC721Checkpointable.sol)
/// @dev Vote weight decays linearly over time. Lock time cannot be more than `MAXTIME` (2 years).
contract VotingEscrow is Initializable, IERC721, IERC721Metadata, IVotes {
enum DepositType {
DEPOSIT_FOR_TYPE,
CREATE_LOCK_TYPE,
INCREASE_LOCK_AMOUNT,
INCREASE_UNLOCK_TIME,
MERGE_TYPE,
SPLIT_TYPE
}
struct LockedBalance {
int128 amount;
uint start;
uint end;
}
struct Point {
int128 bias;
int128 slope; // # -dweight / dt
uint ts;
uint blk; // block
}
/* We cannot really do block numbers per se b/c slope is per time, not per block
* and per block could be fairly bad b/c Ethereum changes blocktimes.
* What we can do is to extrapolate ***At functions */
/// @notice A checkpoint for marking delegated tokenIds from a given timestamp
struct Checkpoint {
uint timestamp;
uint[] tokenIds;
}
/*//////////////////////////////////////////////////////////////
EVENTS
//////////////////////////////////////////////////////////////*/
event Deposit(
address indexed provider,
uint tokenId,
uint value,
uint indexed locktime,
DepositType deposit_type,
uint ts
);
event Withdraw(address indexed provider, uint tokenId, uint value, uint ts);
event Supply(uint prevSupply, uint supply);
/*//////////////////////////////////////////////////////////////
CONSTRUCTOR
//////////////////////////////////////////////////////////////*/
address public immutable token;
address public voter;
address public team;
address public artProxy;
address public distributor;
mapping(uint => Point) public point_history; // epoch -> unsigned point
/// @dev Mapping of interface id to bool about whether or not it's supported
mapping(bytes4 => bool) internal supportedInterfaces;
/// @dev ERC165 interface ID of ERC165
bytes4 internal constant ERC165_INTERFACE_ID = 0x01ffc9a7;
/// @dev ERC165 interface ID of ERC721
bytes4 internal constant ERC721_INTERFACE_ID = 0x80ac58cd;
/// @dev ERC165 interface ID of ERC721Metadata
bytes4 internal constant ERC721_METADATA_INTERFACE_ID = 0x5b5e139f;
/// @dev Current count of token
uint internal tokenId;
/// @notice Contract constructor
/// @param token_addr `SWPx` token address
constructor(address token_addr) {
token = token_addr;
_disableInitializers();
}
function initialize(address art_proxy, address _voter) external initializer {
voter = _voter;
team = msg.sender;
artProxy = art_proxy;
_entered_state = 1;
point_history[0].blk = block.number;
point_history[0].ts = block.timestamp;
supportedInterfaces[ERC165_INTERFACE_ID] = true;
supportedInterfaces[ERC721_INTERFACE_ID] = true;
supportedInterfaces[ERC721_METADATA_INTERFACE_ID] = true;
// mint-ish
emit Transfer(address(0), address(this), tokenId);
// burn-ish
emit Transfer(address(this), address(0), tokenId);
}
/*//////////////////////////////////////////////////////////////
MODIFIERS
//////////////////////////////////////////////////////////////*/
/// @dev reentrancy guard
uint8 internal constant _not_entered = 1;
uint8 internal constant _entered = 2;
uint8 internal _entered_state;
modifier nonreentrant() {
require(_entered_state != _entered);
_entered_state = _entered;
_;
_entered_state = _not_entered;
}
/*///////////////////////////////////////////////////////////////
METADATA STORAGE
//////////////////////////////////////////////////////////////*/
string constant public name = "veSwapX";
string constant public symbol = "veSWPx";
string constant public version = "1.0.0";
uint8 constant public decimals = 18;
function setTeam(address _team) external {
require(msg.sender == team);
team = _team;
}
function setArtProxy(address _proxy) external {
require(msg.sender == team);
artProxy = _proxy;
}
function setDistributor(address _distributor) external {
require(msg.sender == team);
distributor = _distributor;
}
/// @dev Returns current token URI metadata
/// @param _tokenId Token ID to fetch URI for.
function tokenURI(uint _tokenId) external view returns (string memory) {
require(idToOwner[_tokenId] != address(0), "Query for nonexistent token");
LockedBalance memory _locked = locked[_tokenId];
return IVeArtProxy(artProxy)._tokenURI(_tokenId,_balanceOfNFT(_tokenId, block.timestamp),_locked.end,uint(int256(_locked.amount)));
}
/*//////////////////////////////////////////////////////////////
ERC721 BALANCE/OWNER STORAGE
//////////////////////////////////////////////////////////////*/
/// @dev Mapping from NFT ID to the address that owns it.
mapping(uint => address) internal idToOwner;
/// @dev Mapping from owner address to count of his tokens.
mapping(address => uint) internal ownerToNFTokenCount;
/// @dev Returns the address of the owner of the NFT.
/// @param _tokenId The identifier for an NFT.
function ownerOf(uint _tokenId) public view returns (address) {
return idToOwner[_tokenId];
}
/// @dev Returns the number of NFTs owned by `_owner`.
/// Throws if `_owner` is the zero address. NFTs assigned to the zero address are considered invalid.
/// @param _owner Address for whom to query the balance.
function _balance(address _owner) internal view returns (uint) {
return ownerToNFTokenCount[_owner];
}
/// @dev Returns the number of NFTs owned by `_owner`.
/// Throws if `_owner` is the zero address. NFTs assigned to the zero address are considered invalid.
/// @param _owner Address for whom to query the balance.
function balanceOf(address _owner) external view returns (uint) {
return _balance(_owner);
}
/*//////////////////////////////////////////////////////////////
ERC721 APPROVAL STORAGE
//////////////////////////////////////////////////////////////*/
/// @dev Mapping from NFT ID to approved address.
mapping(uint => address) internal idToApprovals;
/// @dev Mapping from owner address to mapping of operator addresses.
mapping(address => mapping(address => bool)) internal ownerToOperators;
mapping(uint => uint) public ownership_change;
/// @dev Get the approved address for a single NFT.
/// @param _tokenId ID of the NFT to query the approval of.
function getApproved(uint _tokenId) external view returns (address) {
return idToApprovals[_tokenId];
}
/// @dev Checks if `_operator` is an approved operator for `_owner`.
/// @param _owner The address that owns the NFTs.
/// @param _operator The address that acts on behalf of the owner.
function isApprovedForAll(address _owner, address _operator) external view returns (bool) {
return (ownerToOperators[_owner])[_operator];
}
/*//////////////////////////////////////////////////////////////
ERC721 LOGIC
//////////////////////////////////////////////////////////////*/
/// @dev Set or reaffirm the approved address for an NFT. The zero address indicates there is no approved address.
/// Throws unless `msg.sender` is the current NFT owner, or an authorized operator of the current owner.
/// Throws if `_tokenId` is not a valid NFT. (NOTE: This is not written the EIP)
/// Throws if `_approved` is the current owner. (NOTE: This is not written the EIP)
/// @param _approved Address to be approved for the given NFT ID.
/// @param _tokenId ID of the token to be approved.
function approve(address _approved, uint _tokenId) public {
address owner = idToOwner[_tokenId];
// Throws if `_tokenId` is not a valid NFT
require(owner != address(0));
// Throws if `_approved` is the current owner
require(_approved != owner);
// Check requirements
bool senderIsOwner = (idToOwner[_tokenId] == msg.sender);
bool senderIsApprovedForAll = (ownerToOperators[owner])[msg.sender];
require(senderIsOwner || senderIsApprovedForAll);
// Set the approval
idToApprovals[_tokenId] = _approved;
emit Approval(owner, _approved, _tokenId);
}
/// @dev Enables or disables approval for a third party ("operator") to manage all of
/// `msg.sender`'s assets. It also emits the ApprovalForAll event.
/// Throws if `_operator` is the `msg.sender`. (NOTE: This is not written the EIP)
/// @notice This works even if sender doesn't own any tokens at the time.
/// @param _operator Address to add to the set of authorized operators.
/// @param _approved True if the operators is approved, false to revoke approval.
function setApprovalForAll(address _operator, bool _approved) external {
// Throws if `_operator` is the `msg.sender`
assert(_operator != msg.sender);
ownerToOperators[msg.sender][_operator] = _approved;
emit ApprovalForAll(msg.sender, _operator, _approved);
}
/* TRANSFER FUNCTIONS */
/// @dev Clear an approval of a given address
/// Throws if `_owner` is not the current owner.
function _clearApproval(address _owner, uint _tokenId) internal {
// Throws if `_owner` is not the current owner
assert(idToOwner[_tokenId] == _owner);
if (idToApprovals[_tokenId] != address(0)) {
// Reset approvals
idToApprovals[_tokenId] = address(0);
}
}
/// @dev Returns whether the given spender can transfer a given token ID
/// @param _spender address of the spender to query
/// @param _tokenId uint ID of the token to be transferred
/// @return bool whether the msg.sender is approved for the given token ID, is an operator of the owner, or is the owner of the token
function _isApprovedOrOwner(address _spender, uint _tokenId) internal view returns (bool) {
address owner = idToOwner[_tokenId];
bool spenderIsOwner = owner == _spender;
bool spenderIsApproved = _spender == idToApprovals[_tokenId];
bool spenderIsApprovedForAll = (ownerToOperators[owner])[_spender];
return spenderIsOwner || spenderIsApproved || spenderIsApprovedForAll;
}
function isApprovedOrOwner(address _spender, uint _tokenId) external view returns (bool) {
return _isApprovedOrOwner(_spender, _tokenId);
}
/// @dev Exeute transfer of a NFT.
/// Throws unless `msg.sender` is the current owner, an authorized operator, or the approved
/// address for this NFT. (NOTE: `msg.sender` not allowed in internal function so pass `_sender`.)
/// Throws if `_to` is the zero address.
/// Throws if `_from` is not the current owner.
/// Throws if `_tokenId` is not a valid NFT.
function _transferFrom(
address _from,
address _to,
uint _tokenId,
address _sender
) internal {
require(attachments[_tokenId] == 0 && !voted[_tokenId], "attached");
// Check requirements
require(_isApprovedOrOwner(_sender, _tokenId));
// Clear approval. Throws if `_from` is not the current owner
_clearApproval(_from, _tokenId);
// Remove NFT. Throws if `_tokenId` is not a valid NFT
_removeTokenFrom(_from, _tokenId);
// auto re-delegate
_moveTokenDelegates(delegates(_from), delegates(_to), _tokenId);
// Add NFT
_addTokenTo(_to, _tokenId);
// Set the block of ownership transfer (for Flash NFT protection)
ownership_change[_tokenId] = block.number;
// Log the transfer
emit Transfer(_from, _to, _tokenId);
}
/// @dev Throws unless `msg.sender` is the current owner, an authorized operator, or the approved address for this NFT.
/// Throws if `_from` is not the current owner.
/// Throws if `_to` is the zero address.
/// Throws if `_tokenId` is not a valid NFT.
/// @notice The caller is responsible to confirm that `_to` is capable of receiving NFTs or else
/// they maybe be permanently lost.
/// @param _from The current owner of the NFT.
/// @param _to The new owner.
/// @param _tokenId The NFT to transfer.
function transferFrom(
address _from,
address _to,
uint _tokenId
) external {
_transferFrom(_from, _to, _tokenId, msg.sender);
}
/// @dev Transfers the ownership of an NFT from one address to another address.
/// Throws unless `msg.sender` is the current owner, an authorized operator, or the
/// approved address for this NFT.
/// Throws if `_from` is not the current owner.
/// Throws if `_to` is the zero address.
/// Throws if `_tokenId` is not a valid NFT.
/// If `_to` is a smart contract, it calls `onERC721Received` on `_to` and throws if
/// the return value is not `bytes4(keccak256("onERC721Received(address,address,uint,bytes)"))`.
/// @param _from The current owner of the NFT.
/// @param _to The new owner.
/// @param _tokenId The NFT to transfer.
function safeTransferFrom(
address _from,
address _to,
uint _tokenId
) external {
safeTransferFrom(_from, _to, _tokenId, "");
}
function _isContract(address account) internal view returns (bool) {
// This method relies on extcodesize, which returns 0 for contracts in
// construction, since the code is only stored at the end of the
// constructor execution.
uint size;
assembly {
size := extcodesize(account)
}
return size > 0;
}
/// @dev Transfers the ownership of an NFT from one address to another address.
/// Throws unless `msg.sender` is the current owner, an authorized operator, or the
/// approved address for this NFT.
/// Throws if `_from` is not the current owner.
/// Throws if `_to` is the zero address.
/// Throws if `_tokenId` is not a valid NFT.
/// If `_to` is a smart contract, it calls `onERC721Received` on `_to` and throws if
/// the return value is not `bytes4(keccak256("onERC721Received(address,address,uint,bytes)"))`.
/// @param _from The current owner of the NFT.
/// @param _to The new owner.
/// @param _tokenId The NFT to transfer.
/// @param _data Additional data with no specified format, sent in call to `_to`.
function safeTransferFrom(
address _from,
address _to,
uint _tokenId,
bytes memory _data
) public {
_transferFrom(_from, _to, _tokenId, msg.sender);
if (_isContract(_to)) {
// Throws if transfer destination is a contract which does not implement 'onERC721Received'
try IERC721Receiver(_to).onERC721Received(msg.sender, _from, _tokenId, _data) returns (bytes4 response) {
if (response != IERC721Receiver(_to).onERC721Received.selector) {
revert("ERC721: ERC721Receiver rejected tokens");
}
} catch (bytes memory reason) {
if (reason.length == 0) {
revert('ERC721: transfer to non ERC721Receiver implementer');
} else {
assembly {
revert(add(32, reason), mload(reason))
}
}
}
}
}
/*//////////////////////////////////////////////////////////////
ERC165 LOGIC
//////////////////////////////////////////////////////////////*/
/// @dev Interface identification is specified in ERC-165.
/// @param _interfaceID Id of the interface
function supportsInterface(bytes4 _interfaceID) external view returns (bool) {
return supportedInterfaces[_interfaceID];
}
/*//////////////////////////////////////////////////////////////
INTERNAL MINT/BURN LOGIC
//////////////////////////////////////////////////////////////*/
/// @dev Mapping from owner address to mapping of index to tokenIds
mapping(address => mapping(uint => uint)) internal ownerToNFTokenIdList;
/// @dev Mapping from NFT ID to index of owner
mapping(uint => uint) internal tokenToOwnerIndex;
/// @dev Get token by index
function tokenOfOwnerByIndex(address _owner, uint _tokenIndex) external view returns (uint) {
return ownerToNFTokenIdList[_owner][_tokenIndex];
}
/// @dev Add a NFT to an index mapping to a given address
/// @param _to address of the receiver
/// @param _tokenId uint ID Of the token to be added
function _addTokenToOwnerList(address _to, uint _tokenId) internal {
uint current_count = _balance(_to);
ownerToNFTokenIdList[_to][current_count] = _tokenId;
tokenToOwnerIndex[_tokenId] = current_count;
}
/// @dev Add a NFT to a given address
/// Throws if `_tokenId` is owned by someone.
function _addTokenTo(address _to, uint _tokenId) internal {
// Throws if `_tokenId` is owned by someone
assert(idToOwner[_tokenId] == address(0));
// Change the owner
idToOwner[_tokenId] = _to;
// Update owner token index tracking
_addTokenToOwnerList(_to, _tokenId);
// Change count tracking
ownerToNFTokenCount[_to] += 1;
}
/// @dev Function to mint tokens
/// Throws if `_to` is zero address.
/// Throws if `_tokenId` is owned by someone.
/// @param _to The address that will receive the minted tokens.
/// @param _tokenId The token id to mint.
/// @return A boolean that indicates if the operation was successful.
function _mint(address _to, uint _tokenId) internal returns (bool) {
// Throws if `_to` is zero address
assert(_to != address(0));
// checkpoint for gov
_moveTokenDelegates(address(0), delegates(_to), _tokenId);
// Add NFT. Throws if `_tokenId` is owned by someone
_addTokenTo(_to, _tokenId);
emit Transfer(address(0), _to, _tokenId);
return true;
}
/// @dev Remove a NFT from an index mapping to a given address
/// @param _from address of the sender
/// @param _tokenId uint ID Of the token to be removed
function _removeTokenFromOwnerList(address _from, uint _tokenId) internal {
// Delete
uint current_count = _balance(_from) - 1;
uint current_index = tokenToOwnerIndex[_tokenId];
if (current_count == current_index) {
// update ownerToNFTokenIdList
ownerToNFTokenIdList[_from][current_count] = 0;
// update tokenToOwnerIndex
tokenToOwnerIndex[_tokenId] = 0;
} else {
uint lastTokenId = ownerToNFTokenIdList[_from][current_count];
// Add
// update ownerToNFTokenIdList
ownerToNFTokenIdList[_from][current_index] = lastTokenId;
// update tokenToOwnerIndex
tokenToOwnerIndex[lastTokenId] = current_index;
// Delete
// update ownerToNFTokenIdList
ownerToNFTokenIdList[_from][current_count] = 0;
// update tokenToOwnerIndex
tokenToOwnerIndex[_tokenId] = 0;
}
}
/// @dev Remove a NFT from a given address
/// Throws if `_from` is not the current owner.
function _removeTokenFrom(address _from, uint _tokenId) internal {
// Throws if `_from` is not the current owner
assert(idToOwner[_tokenId] == _from);
// Change the owner
idToOwner[_tokenId] = address(0);
// Update owner token index tracking
_removeTokenFromOwnerList(_from, _tokenId);
// Change count tracking
ownerToNFTokenCount[_from] -= 1;
}
function _burn(uint _tokenId) internal {
require(_isApprovedOrOwner(msg.sender, _tokenId), "caller is not owner nor approved");
address owner = ownerOf(_tokenId);
// Clear approval
approve(address(0), _tokenId);
// checkpoint for gov
_moveTokenDelegates(delegates(owner), address(0), _tokenId);
// Remove token
//_removeTokenFrom(msg.sender, _tokenId);
_removeTokenFrom(owner, _tokenId);
emit Transfer(owner, address(0), _tokenId);
}
/*//////////////////////////////////////////////////////////////
ESCROW STORAGE
//////////////////////////////////////////////////////////////*/
mapping(uint => uint) public user_point_epoch;
mapping(uint => Point[1000000000]) public user_point_history; // user -> Point[user_epoch]
mapping(uint => LockedBalance) public locked;
uint public epoch;
mapping(uint => int128) public slope_changes; // time -> signed slope change
uint public supply;
uint internal constant MAXTIME = 2 * 365 * 86400;
int128 internal constant iMAXTIME = 2 * 365 * 86400;
uint internal constant MULTIPLIER = 1 ether;
event DepositCheckpoint(address user, uint256 tokenId, int128 bias, int128 slope, uint ts, uint blk);
/*//////////////////////////////////////////////////////////////
ESCROW LOGIC
//////////////////////////////////////////////////////////////*/
/// @notice Get the most recently recorded rate of voting power decrease for `_tokenId`
/// @param _tokenId token of the NFT
/// @return Value of the slope
function get_last_user_slope(uint _tokenId) external view returns (int128) {
uint uepoch = user_point_epoch[_tokenId];
return user_point_history[_tokenId][uepoch].slope;
}
/// @notice Get the timestamp for checkpoint `_idx` for `_tokenId`
/// @param _tokenId token of the NFT
/// @param _idx User epoch number
/// @return Epoch time of the checkpoint
function user_point_history__ts(uint _tokenId, uint _idx) external view returns (uint) {
return user_point_history[_tokenId][_idx].ts;
}
/// @notice Get timestamp when `_tokenId`'s lock started
/// @param _tokenId User NFT
/// @return Epoch time of the lock start
function locked__start(uint _tokenId) external view returns (uint) {
return locked[_tokenId].start;
}
/// @notice Get timestamp when `_tokenId`'s lock finishes
/// @param _tokenId User NFT
/// @return Epoch time of the lock end
function locked__end(uint _tokenId) external view returns (uint) {
return locked[_tokenId].end;
}
/// @notice Record global and per-user data to checkpoint
/// @param _tokenId NFT token ID. No user checkpoint if 0
/// @param old_locked Pevious locked amount / end lock time for the user
/// @param new_locked New locked amount / end lock time for the user
function _checkpoint(
uint _tokenId,
LockedBalance memory old_locked,
LockedBalance memory new_locked
) internal {
Point memory u_old;
Point memory u_new;
int128 old_dslope = 0;
int128 new_dslope = 0;
uint _epoch = epoch;
if (_tokenId != 0) {
// Calculate slopes and biases
// Kept at zero when they have to
if (old_locked.end > block.timestamp && old_locked.amount > 0) {
u_old.slope = old_locked.amount / iMAXTIME;
u_old.bias = u_old.slope * int128(int256(old_locked.end - block.timestamp));
}
if (new_locked.end > block.timestamp && new_locked.amount > 0) {
u_new.slope = new_locked.amount / iMAXTIME;
u_new.bias = u_new.slope * int128(int256(new_locked.end - block.timestamp));
}
// Read values of scheduled changes in the slope
// old_locked.end can be in the past and in the future
// new_locked.end can ONLY by in the FUTURE unless everything expired: than zeros
old_dslope = slope_changes[old_locked.end];
if (new_locked.end != 0) {
if (new_locked.end == old_locked.end) {
new_dslope = old_dslope;
} else {
new_dslope = slope_changes[new_locked.end];
}
}
}
Point memory last_point = Point({bias: 0, slope: 0, ts: block.timestamp, blk: block.number});
if (_epoch > 0) {
last_point = point_history[_epoch];
}
uint last_checkpoint = last_point.ts;
// initial_last_point is used for extrapolation to calculate block number
// (approximately, for *At methods) and save them
// as we cannot figure that out exactly from inside the contract
Point memory initial_last_point = last_point;
uint block_slope = 0; // dblock/dt
if (block.timestamp > last_point.ts) {
block_slope = (MULTIPLIER * (block.number - last_point.blk)) / (block.timestamp - last_point.ts);
}
// If last point is already recorded in this block, slope=0
// But that's ok b/c we know the block in such case
// Go over weeks to fill history and calculate what the current point is
{
uint t_i = (last_checkpoint / Constants.EPOCH_LENGTH) * Constants.EPOCH_LENGTH;
for (uint i = 0; i < 255; ++i) {
// Hopefully it won't happen that this won't get used in 5 years!
// If it does, users will be able to withdraw but vote weight will be broken
t_i += Constants.EPOCH_LENGTH;
int128 d_slope = 0;
if (t_i > block.timestamp) {
t_i = block.timestamp;
} else {
d_slope = slope_changes[t_i];
}
last_point.bias -= last_point.slope * int128(int256(t_i - last_checkpoint));
last_point.slope += d_slope;
if (last_point.bias < 0) {
// This can happen
last_point.bias = 0;
}
if (last_point.slope < 0) {
// This cannot happen - just in case
last_point.slope = 0;
}
last_checkpoint = t_i;
last_point.ts = t_i;
last_point.blk = initial_last_point.blk + (block_slope * (t_i - initial_last_point.ts)) / MULTIPLIER;
_epoch += 1;
if (t_i == block.timestamp) {
last_point.blk = block.number;
break;
} else {
point_history[_epoch] = last_point;
}
}
}
epoch = _epoch;
// Now point_history is filled until t=now
if (_tokenId != 0) {
// If last point was in this block, the slope change has been applied already
// But in such case we have 0 slope(s)
last_point.slope += (u_new.slope - u_old.slope);
last_point.bias += (u_new.bias - u_old.bias);
if (last_point.slope < 0) {
last_point.slope = 0;
}
if (last_point.bias < 0) {
last_point.bias = 0;
}
}
// Record the changed point into history
point_history[_epoch] = last_point;
if (_tokenId != 0) {
// Schedule the slope changes (slope is going down)
// We subtract new_user_slope from [new_locked.end]
// and add old_user_slope to [old_locked.end]
if (old_locked.end > block.timestamp) {
// old_dslope was <something> - u_old.slope, so we cancel that
old_dslope += u_old.slope;
if (new_locked.end == old_locked.end) {
old_dslope -= u_new.slope; // It was a new deposit, not extension
}
slope_changes[old_locked.end] = old_dslope;
}
if (new_locked.end > block.timestamp) {
if (new_locked.end > old_locked.end) {
new_dslope -= u_new.slope; // old slope disappeared at this point
slope_changes[new_locked.end] = new_dslope;
}
// else: we recorded it already in old_dslope
}
// Now handle user history
uint user_epoch = user_point_epoch[_tokenId] + 1;
user_point_epoch[_tokenId] = user_epoch;
u_new.ts = block.timestamp;
u_new.blk = block.number;
user_point_history[_tokenId][user_epoch] = u_new;
emit DepositCheckpoint(ownerOf(_tokenId), _tokenId, u_new.bias, u_new.slope, u_new.ts, u_new.blk);
}
}
/// @notice Deposit and lock tokens for a user
/// @param _tokenId NFT that holds lock
/// @param _value Amount to deposit
/// @param unlock_time New time when to unlock the tokens, or 0 if unchanged
/// @param locked_balance Previous locked amount / timestamp
/// @param deposit_type The type of deposit
function _deposit_for(
uint _tokenId,
uint _value,
uint unlock_time,
LockedBalance memory locked_balance,
DepositType deposit_type
) internal {
LockedBalance memory _locked = locked_balance;
uint supply_before = supply;
supply = supply_before + _value;
LockedBalance memory old_locked;
(old_locked.amount, old_locked.start, old_locked.end) = (_locked.amount, _locked.start, _locked.end);
// Adding to existing lock, or if a lock is expired - creating a new one
_locked.amount += int128(int256(_value));
if (unlock_time != 0) {
_locked.end = unlock_time;
}
if (_locked.start == 0) {
_locked.start = block.timestamp;
}
locked[_tokenId] = _locked;
// Possibilities:
// Both old_locked.end could be current or expired (>/< block.timestamp)
// value == 0 (extend lock) or value > 0 (add to lock or extend lock)
// _locked.end > block.timestamp (always)
_checkpoint(_tokenId, old_locked, _locked);
address from = msg.sender;
if (_value != 0 && deposit_type != DepositType.MERGE_TYPE && deposit_type != DepositType.SPLIT_TYPE ) {
assert(IERC20(token).transferFrom(from, address(this), _value));
}
emit Deposit(from, _tokenId, _value, _locked.end, deposit_type, block.timestamp);
emit Supply(supply_before, supply_before + _value);
}
function block_number() external view returns (uint) {
return block.number;
}
/// @notice Record global data to checkpoint
function checkpoint() external {
_checkpoint(0, LockedBalance(0, 0, 0), LockedBalance(0, 0, 0));
}
/// @notice Deposit `_value` tokens for `_tokenId` and add to the lock
/// @dev Anyone (even a smart contract) can deposit for someone else, but
/// cannot extend their locktime and deposit for a brand new user
/// @param _tokenId lock NFT
/// @param _value Amount to add to user's lock
function deposit_for(uint _tokenId, uint _value) external nonreentrant returns(uint votingPower) {
LockedBalance memory _locked = locked[_tokenId];
require(_value > 0); // dev: need non-zero value
require(_locked.amount > 0, 'No existing lock found');
require(_locked.end > block.timestamp, 'Cannot add to expired lock. Withdraw');
_deposit_for(_tokenId, _value, 0, _locked, DepositType.DEPOSIT_FOR_TYPE);
return _balanceOfNFT(_tokenId, block.timestamp);
}
/// @notice Deposit `_value` tokens for `_to` and lock for `_lock_duration`
/// @param _value Amount to deposit
/// @param _lock_duration Number of seconds to lock tokens for (rounded down to nearest week)
/// @param _to Address to deposit
function _create_lock(uint _value, uint _lock_duration, address _to) internal returns (uint) {
uint unlock_time = (block.timestamp + _lock_duration) / Constants.EPOCH_LENGTH * Constants.EPOCH_LENGTH; // Locktime is rounded down to weeks
require(_value > 0); // dev: need non-zero value
require(unlock_time > block.timestamp, 'Can only lock until time in the future');
require(unlock_time <= block.timestamp + MAXTIME, 'Voting lock can be 2 years max');
++tokenId;
uint _tokenId = tokenId;
_mint(_to, _tokenId);
_deposit_for(_tokenId, _value, unlock_time, locked[_tokenId], DepositType.CREATE_LOCK_TYPE);
return _tokenId;
}
/// @notice Deposit `_value` tokens for `msg.sender` and lock for `_lock_duration`
/// @param _value Amount to deposit
/// @param _lock_duration Number of seconds to lock tokens for (rounded down to nearest week)
function create_lock(uint _value, uint _lock_duration) external nonreentrant returns (uint newTokenId, uint votingPower) {
newTokenId = _create_lock(_value, _lock_duration, msg.sender);
votingPower = _balanceOfNFT(newTokenId, block.timestamp);
}
/// @notice Deposit `_value` tokens for `_to` and lock for `_lock_duration`
/// @param _value Amount to deposit
/// @param _lock_duration Number of seconds to lock tokens for (rounded down to nearest week)
/// @param _to Address to deposit
function create_lock_for(uint _value, uint _lock_duration, address _to) external nonreentrant returns (uint newTokenId, uint votingPower) {
newTokenId = _create_lock(_value, _lock_duration, _to);
votingPower = _balanceOfNFT(newTokenId, block.timestamp);
}
/// @notice Deposit `_value` additional tokens for `_tokenId` without modifying the unlock time
/// @param _value Amount of tokens to deposit and add to the lock
function increase_amount(uint _tokenId, uint _value) external nonreentrant returns (uint votingPower) {
assert(_isApprovedOrOwner(msg.sender, _tokenId));
LockedBalance memory _locked = locked[_tokenId];
assert(_value > 0); // dev: need non-zero value
require(_locked.amount > 0, 'No existing lock found');
require(_locked.end > block.timestamp, 'Cannot add to expired lock. Withdraw');
_deposit_for(_tokenId, _value, 0, _locked, DepositType.INCREASE_LOCK_AMOUNT);
return _balanceOfNFT(_tokenId, block.timestamp);
}
/// @notice Extend the unlock time for `_tokenId`
/// @param _lock_duration New number of seconds until tokens unlock
function increase_unlock_time(uint _tokenId, uint _lock_duration) external nonreentrant returns (uint votingPower) {
assert(_isApprovedOrOwner(msg.sender, _tokenId));
LockedBalance memory _locked = locked[_tokenId];
uint unlock_time = (block.timestamp + _lock_duration) / Constants.EPOCH_LENGTH * Constants.EPOCH_LENGTH; // Locktime is rounded down to weeks
require(_locked.end > block.timestamp, 'Lock expired');
require(_locked.amount > 0, 'Nothing is locked');
require(unlock_time > _locked.end, 'Can only increase lock duration');
require(unlock_time <= block.timestamp + MAXTIME, 'Voting lock can be 2 years max');
_deposit_for(_tokenId, 0, unlock_time, _locked, DepositType.INCREASE_UNLOCK_TIME);
return _balanceOfNFT(_tokenId, block.timestamp);
}
/// @notice Withdraw all tokens for `_tokenId`
/// @dev Only possible if the lock has expired
function withdraw(uint _tokenId) external nonreentrant {
assert(_isApprovedOrOwner(msg.sender, _tokenId));
require(attachments[_tokenId] == 0 && !voted[_tokenId], "attached");
LockedBalance memory _locked = locked[_tokenId];
require(block.timestamp >= _locked.end, "The lock didn't expire");
uint value = uint(int256(_locked.amount));
locked[_tokenId] = LockedBalance(0, 0, 0);
uint supply_before = supply;
supply = supply_before - value;
// old_locked can have either expired <= timestamp or zero end
// _locked has only 0 end
// Both can have >= 0 amount
_checkpoint(_tokenId, _locked, LockedBalance(0, 0, 0));
assert(IERC20(token).transfer(msg.sender, value));
// Burn the NFT
_burn(_tokenId);
emit Withdraw(msg.sender, _tokenId, value, block.timestamp);
emit Supply(supply_before, supply_before - value);
}
/*///////////////////////////////////////////////////////////////
GAUGE VOTING STORAGE
//////////////////////////////////////////////////////////////*/
// The following ERC20/minime-compatible methods are not real balanceOf and supply!
// They measure the weights for the purpose of voting, so they don't represent
// real coins.
/// @notice Binary search to estimate timestamp for block number
/// @param _block Block to find
/// @param max_epoch Don't go beyond this epoch
/// @return Approximate timestamp for block
function _find_block_epoch(uint _block, uint max_epoch) internal view returns (uint) {
// Binary search
uint _min = 0;
uint _max = max_epoch;
for (uint i = 0; i < 128; ++i) {
// Will be always enough for 128-bit numbers
if (_min >= _max) {
break;
}
uint _mid = (_min + _max + 1) / 2;
if (point_history[_mid].blk <= _block) {
_min = _mid;
} else {
_max = _mid - 1;
}
}
return _min;
}
/// @notice Get the current voting power for `_tokenId`
/// @dev Adheres to the ERC20 `balanceOf` interface for Aragon compatibility
/// @param _tokenId NFT for lock
/// @param _t Epoch time to return voting power at
/// @return User voting power
function _balanceOfNFT(uint _tokenId, uint _t) internal view returns (uint) {
uint _epoch = user_point_epoch[_tokenId];
if (_epoch == 0) {
return 0;
} else {
Point memory last_point = user_point_history[_tokenId][_epoch];
last_point.bias -= last_point.slope * int128(int256(_t) - int256(last_point.ts));
if (last_point.bias < 0) {
last_point.bias = 0;
}
return uint(int256(last_point.bias));
}
}
function balanceOfNFT(uint _tokenId) external view returns (uint) {
if (ownership_change[_tokenId] == block.number) return 0;
return _balanceOfNFT(_tokenId, block.timestamp);
}
function balanceOfNFTAt(uint _tokenId, uint _t) external view returns (uint) {
return _balanceOfNFT(_tokenId, _t);
}
/// @notice Measure voting power of `_tokenId` at block height `_block`
/// @dev Adheres to MiniMe `balanceOfAt` interface: https://github.com/Giveth/minime
/// @param _tokenId User's wallet NFT
/// @param _block Block to calculate the voting power at
/// @return Voting power
function _balanceOfAtNFT(uint _tokenId, uint _block) internal view returns (uint) {
// Copying and pasting totalSupply code because Vyper cannot pass by
// reference yet
assert(_block <= block.number);
// Binary search
uint _min = 0;
uint _max = user_point_epoch[_tokenId];
for (uint i = 0; i < 128; ++i) {
// Will be always enough for 128-bit numbers
if (_min >= _max) {
break;
}
uint _mid = (_min + _max + 1) / 2;
if (user_point_history[_tokenId][_mid].blk <= _block) {
_min = _mid;
} else {
_max = _mid - 1;
}
}
Point memory upoint = user_point_history[_tokenId][_min];
uint max_epoch = epoch;
uint _epoch = _find_block_epoch(_block, max_epoch);
Point memory point_0 = point_history[_epoch];
uint d_block = 0;
uint d_t = 0;
if (_epoch < max_epoch) {
Point memory point_1 = point_history[_epoch + 1];
d_block = point_1.blk - point_0.blk;
d_t = point_1.ts - point_0.ts;
} else {
d_block = block.number - point_0.blk;
d_t = block.timestamp - point_0.ts;
}
uint block_time = point_0.ts;
if (d_block != 0) {
block_time += (d_t * (_block - point_0.blk)) / d_block;
}
upoint.bias -= upoint.slope * int128(int256(block_time - upoint.ts));
if (upoint.bias >= 0) {
return uint(uint128(upoint.bias));
} else {
return 0;
}
}
function balanceOfAtNFT(uint _tokenId, uint _block) external view returns (uint) {
return _balanceOfAtNFT(_tokenId, _block);
}
/// @notice Calculate total voting power at some point in the past
/// @param _block Block to calculate the total voting power at
/// @return Total voting power at `_block`
function totalSupplyAt(uint _block) external view returns (uint) {
assert(_block <= block.number);
uint _epoch = epoch;
uint target_epoch = _find_block_epoch(_block, _epoch);
Point memory point = point_history[target_epoch];
uint dt = 0;
if (target_epoch < _epoch) {
Point memory point_next = point_history[target_epoch + 1];
if (point.blk != point_next.blk) {
dt = ((_block - point.blk) * (point_next.ts - point.ts)) / (point_next.blk - point.blk);
}
} else {
if (point.blk != block.number) {
dt = ((_block - point.blk) * (block.timestamp - point.ts)) / (block.number - point.blk);
}
}
// Now dt contains info on how far are we beyond point
return _supply_at(point, point.ts + dt);
}
/// @notice Calculate total voting power at some point in the past
/// @param point The point (bias/slope) to start search from
/// @param t Time to calculate the total voting power at
/// @return Total voting power at that time
function _supply_at(Point memory point, uint t) internal view returns (uint) {
Point memory last_point = point;
uint t_i = (last_point.ts / Constants.EPOCH_LENGTH) * Constants.EPOCH_LENGTH;
for (uint i = 0; i < 255; ++i) {
t_i += Constants.EPOCH_LENGTH;
int128 d_slope = 0;
if (t_i > t) {
t_i = t;
} else {
d_slope = slope_changes[t_i];
}
last_point.bias -= last_point.slope * int128(int256(t_i - last_point.ts));
if (t_i == t) {
break;
}
last_point.slope += d_slope;
last_point.ts = t_i;
}
if (last_point.bias < 0) {
last_point.bias = 0;
}
return uint(uint128(last_point.bias));
}
function totalSupply() external view returns (uint) {
return totalSupplyAtT(block.timestamp);
}
/// @notice Calculate total voting power
/// @dev Adheres to the ERC20 `totalSupply` interface for Aragon compatibility
/// @return Total voting power
function totalSupplyAtT(uint t) public view returns (uint) {
uint _epoch = epoch;
Point memory last_point = point_history[_epoch];
return _supply_at(last_point, t);
}
/*///////////////////////////////////////////////////////////////
GAUGE VOTING LOGIC
//////////////////////////////////////////////////////////////*/
mapping(uint => uint) public attachments;
mapping(uint => bool) public voted;
function setVoter(address _voter) external {
require(msg.sender == team);
voter = _voter;
}
function voting(uint _tokenId) external {
require(msg.sender == voter);
voted[_tokenId] = true;
}
function abstain(uint _tokenId) external {
require(msg.sender == voter);
voted[_tokenId] = false;
}
function attach(uint _tokenId) external {
require(msg.sender == voter);
attachments[_tokenId] = attachments[_tokenId] + 1;
}
function detach(uint _tokenId) external {
require(msg.sender == voter);
attachments[_tokenId] = attachments[_tokenId] - 1;
}
function merge(uint _from, uint _to) external returns (uint votingPower) {
require(attachments[_from] == 0 && !voted[_from], "attached");
require(_from != _to);
require(_isApprovedOrOwner(msg.sender, _from));
require(_isApprovedOrOwner(msg.sender, _to));
LockedBalance memory _locked0 = locked[_from];
LockedBalance memory _locked1 = locked[_to];
require(_locked0.end > block.timestamp && _locked1.end > block.timestamp);
uint value0 = uint(int256(_locked0.amount));
uint end = _locked0.end >= _locked1.end ? _locked0.end : _locked1.end;
_locked1.start = _locked0.start >= _locked1.start ? _locked1.start : _locked0.start;
locked[_from] = LockedBalance(0, 0, 0);
supply = supply - value0;
_checkpoint(_from, _locked0, LockedBalance(0, 0, 0));
_burn(_from);
_deposit_for(_to, value0, end, _locked1, DepositType.MERGE_TYPE);
return _balanceOfNFT(_to, block.timestamp);
}
/**
* @notice split NFT into multiple
* @param amounts % of split
* @param _tokenId NFTs ID
*/
function split(uint[] memory amounts, uint _tokenId) external returns(uint256[] memory newTokenIds, uint256[] memory votingPowers) {
// check permission and vote
require(attachments[_tokenId] == 0 && !voted[_tokenId], "attached");
require(_isApprovedOrOwner(msg.sender, _tokenId));
// save old data and totalWeight
address _to = idToOwner[_tokenId];
LockedBalance memory _locked = locked[_tokenId];
require(_locked.amount > 0); // dev: need non-zero value
// require()
// reset supply, _deposit_for increase it
supply = supply - uint128(_locked.amount);
uint i;
uint totalWeight = 0;
for(i = 0; i < amounts.length; i++){
totalWeight += amounts[i];
}
// remove old data
locked[_tokenId] = LockedBalance(0, 0, 0);
_checkpoint(_tokenId, _locked, LockedBalance(0, 0, 0));
_burn(_tokenId);
// save end
uint unlock_time = _locked.end;
require(unlock_time > block.timestamp, 'Can only lock until time in the future');
require(unlock_time <= block.timestamp + MAXTIME, 'Voting lock can be 2 years max');
newTokenIds = new uint256[](amounts.length);
votingPowers = new uint256[](amounts.length);
// mint
uint _value = 0;
for(i = 0; i < amounts.length; i++){
++tokenId;
_tokenId = tokenId;
_mint(_to, _tokenId);
_value = uint128(_locked.amount) * amounts[i] / totalWeight;
locked[_tokenId].start = _locked.start;
_deposit_for(_tokenId, _value, unlock_time, locked[_tokenId], DepositType.SPLIT_TYPE);
newTokenIds[i] = _tokenId;
votingPowers[i] = _balanceOfNFT(_tokenId, block.timestamp);
}
}
/*///////////////////////////////////////////////////////////////
DAO VOTING STORAGE
//////////////////////////////////////////////////////////////*/
/// @notice The EIP-712 typehash for the contract's domain
bytes32 public constant DOMAIN_TYPEHASH = keccak256("EIP712Domain(string name,uint256 chainId,address verifyingContract)");
/// @notice The EIP-712 typehash for the delegation struct used by the contract
bytes32 public constant DELEGATION_TYPEHASH = keccak256("Delegation(address delegatee,uint256 nonce,uint256 expiry)");
/// @notice A record of each accounts delegate
mapping(address => address) private _delegates;
uint public constant MAX_DELEGATES = 1024; // avoid too much gas
/// @notice A record of delegated token checkpoints for each account, by index
mapping(address => mapping(uint32 => Checkpoint)) public checkpoints;
/// @notice The number of checkpoints for each account
mapping(address => uint32) public numCheckpoints;
/// @notice A record of states for signing / validating signatures
mapping(address => uint) public nonces;
/**
* @notice Overrides the standard `Comp.sol` delegates mapping to return
* the delegator's own address if they haven't delegated.
* This avoids having to delegate to oneself.
*/
function delegates(address delegator) public view returns (address) {
address current = _delegates[delegator];
return current == address(0) ? delegator : current;
}
/**
* @notice Gets the current votes balance for `account`
* @param account The address to get votes balance
* @return The number of current votes for `account`
*/
function getVotes(address account) external view returns (uint) {
uint32 nCheckpoints = numCheckpoints[account];
if (nCheckpoints == 0) {
return 0;
}
uint[] storage _tokenIds = checkpoints[account][nCheckpoints - 1].tokenIds;
uint votes = 0;
for (uint i = 0; i < _tokenIds.length; i++) {
uint tId = _tokenIds[i];
votes = votes + _balanceOfNFT(tId, block.timestamp);
}
return votes;
}
function getPastVotesIndex(address account, uint timestamp) public view returns (uint32) {
uint32 nCheckpoints = numCheckpoints[account];
if (nCheckpoints == 0) {
return 0;
}
// First check most recent balance
if (checkpoints[account][nCheckpoints - 1].timestamp <= timestamp) {
return (nCheckpoints - 1);
}
// Next check implicit zero balance
if (checkpoints[account][0].timestamp > timestamp) {
return 0;
}
uint32 lower = 0;
uint32 upper = nCheckpoints - 1;
while (upper > lower) {
uint32 center = upper - (upper - lower) / 2; // ceil, avoiding overflow
Checkpoint storage cp = checkpoints[account][center];
if (cp.timestamp == timestamp) {
return center;
} else if (cp.timestamp < timestamp) {
lower = center;
} else {
upper = center - 1;
}
}
return lower;
}
function getPastVotes(address account, uint timestamp)
public
view
returns (uint)
{
uint32 _checkIndex = getPastVotesIndex(account, timestamp);
// Sum votes
uint[] storage _tokenIds = checkpoints[account][_checkIndex].tokenIds;
uint votes = 0;
for (uint i = 0; i < _tokenIds.length; i++) {
uint tId = _tokenIds[i];
// Use the provided input timestamp here to get the right decay
votes = votes + _balanceOfNFT(tId, timestamp);
}
return votes;
}
function getPastTotalSupply(uint256 timestamp) external view returns (uint) {
return totalSupplyAtT(timestamp);
}
/*///////////////////////////////////////////////////////////////
DAO VOTING LOGIC
//////////////////////////////////////////////////////////////*/
function _moveTokenDelegates(
address srcRep,
address dstRep,
uint _tokenId
) internal {
if (srcRep != dstRep && _tokenId > 0) {
if (srcRep != address(0)) {
uint32 srcRepNum = numCheckpoints[srcRep];
uint[] storage srcRepOld = srcRepNum > 0
? checkpoints[srcRep][srcRepNum - 1].tokenIds
: checkpoints[srcRep][0].tokenIds;
uint32 nextSrcRepNum = _findWhatCheckpointToWrite(srcRep);
uint[] storage srcRepNew = checkpoints[srcRep][
nextSrcRepNum
].tokenIds;
// All the same except _tokenId
for (uint i = 0; i < srcRepOld.length; i++) {
uint tId = srcRepOld[i];
if (tId != _tokenId) {
srcRepNew.push(tId);
}
}
numCheckpoints[srcRep] = srcRepNum + 1;
}
if (dstRep != address(0)) {
uint32 dstRepNum = numCheckpoints[dstRep];
uint[] storage dstRepOld = dstRepNum > 0
? checkpoints[dstRep][dstRepNum - 1].tokenIds
: checkpoints[dstRep][0].tokenIds;
uint32 nextDstRepNum = _findWhatCheckpointToWrite(dstRep);
uint[] storage dstRepNew = checkpoints[dstRep][
nextDstRepNum
].tokenIds;
// All the same plus _tokenId
require(
dstRepOld.length + 1 <= MAX_DELEGATES,
"dstRep would have too many tokenIds"
);
for (uint i = 0; i < dstRepOld.length; i++) {
uint tId = dstRepOld[i];
dstRepNew.push(tId);
}
dstRepNew.push(_tokenId);
numCheckpoints[dstRep] = dstRepNum + 1;
}
}
}
function _findWhatCheckpointToWrite(address account)
internal
view
returns (uint32)
{
uint _timestamp = block.timestamp;
uint32 _nCheckPoints = numCheckpoints[account];
if (
_nCheckPoints > 0 &&
checkpoints[account][_nCheckPoints - 1].timestamp == _timestamp
) {
return _nCheckPoints - 1;
} else {
return _nCheckPoints;
}
}
function _moveAllDelegates(
address owner,
address srcRep,
address dstRep
) internal {
// You can only redelegate what you own
if (srcRep != dstRep) {
if (srcRep != address(0)) {
uint32 srcRepNum = numCheckpoints[srcRep];
uint[] storage srcRepOld = srcRepNum > 0
? checkpoints[srcRep][srcRepNum - 1].tokenIds
: checkpoints[srcRep][0].tokenIds;
uint32 nextSrcRepNum = _findWhatCheckpointToWrite(srcRep);
uint[] storage srcRepNew = checkpoints[srcRep][
nextSrcRepNum
].tokenIds;
// All the same except what owner owns
for (uint i = 0; i < srcRepOld.length; i++) {
uint tId = srcRepOld[i];
if (idToOwner[tId] != owner) {
srcRepNew.push(tId);
}
}
numCheckpoints[srcRep] = srcRepNum + 1;
}
if (dstRep != address(0)) {
uint32 dstRepNum = numCheckpoints[dstRep];
uint[] storage dstRepOld = dstRepNum > 0
? checkpoints[dstRep][dstRepNum - 1].tokenIds
: checkpoints[dstRep][0].tokenIds;
uint32 nextDstRepNum = _findWhatCheckpointToWrite(dstRep);
uint[] storage dstRepNew = checkpoints[dstRep][
nextDstRepNum
].tokenIds;
uint ownerTokenCount = ownerToNFTokenCount[owner];
require(
dstRepOld.length + ownerTokenCount <= MAX_DELEGATES,
"dstRep would have too many tokenIds"
);
// All the same
for (uint i = 0; i < dstRepOld.length; i++) {
uint tId = dstRepOld[i];
dstRepNew.push(tId);
}
// Plus all that's owned
for (uint i = 0; i < ownerTokenCount; i++) {
uint tId = ownerToNFTokenIdList[owner][i];
dstRepNew.push(tId);
}
numCheckpoints[dstRep] = dstRepNum + 1;
}
}
}
function _delegate(address delegator, address delegatee) internal {
/// @notice differs from `_delegate()` in `Comp.sol` to use `delegates` override method to simulate auto-delegation
address currentDelegate = delegates(delegator);
_delegates[delegator] = delegatee;
emit DelegateChanged(delegator, currentDelegate, delegatee);
_moveAllDelegates(delegator, currentDelegate, delegatee);
}
/**
* @notice Delegate votes from `msg.sender` to `delegatee`
* @param delegatee The address to delegate votes to
*/
function delegate(address delegatee) public {
if (delegatee == address(0)) delegatee = msg.sender;
return _delegate(msg.sender, delegatee);
}
function delegateBySig(
address delegatee,
uint nonce,
uint expiry,
uint8 v,
bytes32 r,
bytes32 s
) public {
require(delegatee != msg.sender);
require(delegatee != address(0));
bytes32 domainSeparator = keccak256(
abi.encode(
DOMAIN_TYPEHASH,
keccak256(bytes(name)),
keccak256(bytes(version)),
block.chainid,
address(this)
)
);
bytes32 structHash = keccak256(
abi.encode(DELEGATION_TYPEHASH, delegatee, nonce, expiry)
);
bytes32 digest = keccak256(
abi.encodePacked("\x19\x01", domainSeparator, structHash)
);
address signatory = ecrecover(digest, v, r, s);
require(
signatory != address(0),
"VotingEscrow::delegateBySig: invalid signature"
);
require(
nonce == nonces[signatory]++,
"VotingEscrow::delegateBySig: invalid nonce"
);
require(
block.timestamp <= expiry,
"VotingEscrow::delegateBySig: signature expired"
);
return _delegate(signatory, delegatee);
}
}