// SPDX-License-Identifier: MITpragmasolidity >=0.6.2 <0.8.0;/**
* @dev Collection of functions related to the address type
*/libraryAddress{
/**
* @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
* ====
*/functionisContract(address account) internalviewreturns (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.uint256 size;
// solhint-disable-next-line no-inline-assemblyassembly { size :=extcodesize(account) }
return size >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].
*/functionsendValue(addresspayable recipient, uint256 amount) internal{
require(address(this).balance>= amount, "Address: insufficient balance");
// solhint-disable-next-line avoid-low-level-calls, avoid-call-value
(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._
*/functionfunctionCall(address target, bytesmemory data) internalreturns (bytesmemory) {
return functionCall(target, data, "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._
*/functionfunctionCall(address target, bytesmemory data, stringmemory errorMessage) internalreturns (bytesmemory) {
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._
*/functionfunctionCallWithValue(address target, bytesmemory data, uint256 value) internalreturns (bytesmemory) {
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._
*/functionfunctionCallWithValue(address target, bytesmemory data, uint256 value, stringmemory errorMessage) internalreturns (bytesmemory) {
require(address(this).balance>= value, "Address: insufficient balance for call");
require(isContract(target), "Address: call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytesmemory returndata) = target.call{ value: value }(data);
return _verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/functionfunctionStaticCall(address target, bytesmemory data) internalviewreturns (bytesmemory) {
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._
*/functionfunctionStaticCall(address target, bytesmemory data, stringmemory errorMessage) internalviewreturns (bytesmemory) {
require(isContract(target), "Address: static call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytesmemory returndata) = target.staticcall(data);
return _verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/functionfunctionDelegateCall(address target, bytesmemory data) internalreturns (bytesmemory) {
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._
*/functionfunctionDelegateCall(address target, bytesmemory data, stringmemory errorMessage) internalreturns (bytesmemory) {
require(isContract(target), "Address: delegate call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytesmemory returndata) = target.delegatecall(data);
return _verifyCallResult(success, returndata, errorMessage);
}
function_verifyCallResult(bool success, bytesmemory returndata, stringmemory errorMessage) privatepurereturns(bytesmemory) {
if (success) {
return returndata;
} else {
// Look for revert reason and bubble it up if presentif (returndata.length>0) {
// The easiest way to bubble the revert reason is using memory via assembly// solhint-disable-next-line no-inline-assemblyassembly {
let returndata_size :=mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
}
Contract Source Code
File 2 of 25: Context.sol
// SPDX-License-Identifier: MITpragmasolidity >=0.6.0 <0.8.0;/*
* @dev Provides information about the current execution context, including the
* sender of the transaction and its data. While these are generally available
* via msg.sender and msg.data, they should not be accessed in such a direct
* manner, since when dealing with GSN meta-transactions the account sending and
* paying for execution may not be the actual sender (as far as an application
* is concerned).
*
* This contract is only required for intermediate, library-like contracts.
*/abstractcontractContext{
function_msgSender() internalviewvirtualreturns (addresspayable) {
returnmsg.sender;
}
function_msgData() internalviewvirtualreturns (bytesmemory) {
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691returnmsg.data;
}
}
Contract Source Code
File 3 of 25: Counters.sol
// SPDX-License-Identifier: MITpragmasolidity >=0.6.0 <0.8.0;import"../math/SafeMath.sol";
/**
* @title Counters
* @author Matt Condon (@shrugs)
* @dev Provides counters that can only be incremented or decremented by one. This can be used e.g. to track the number
* of elements in a mapping, issuing ERC721 ids, or counting request ids.
*
* Include with `using Counters for Counters.Counter;`
* Since it is not possible to overflow a 256 bit integer with increments of one, `increment` can skip the {SafeMath}
* overflow check, thereby saving gas. This does assume however correct usage, in that the underlying `_value` is never
* directly accessed.
*/libraryCounters{
usingSafeMathforuint256;
structCounter {
// This variable should never be directly accessed by users of the library: interactions must be restricted to// the library's function. As of Solidity v0.5.2, this cannot be enforced, though there is a proposal to add// this feature: see https://github.com/ethereum/solidity/issues/4637uint256 _value; // default: 0
}
functioncurrent(Counter storage counter) internalviewreturns (uint256) {
return counter._value;
}
functionincrement(Counter storage counter) internal{
// The {SafeMath} overflow check can be skipped here, see the comment at the top
counter._value +=1;
}
functiondecrement(Counter storage counter) internal{
counter._value = counter._value.sub(1);
}
}
Contract Source Code
File 4 of 25: ERC165.sol
// SPDX-License-Identifier: MITpragmasolidity >=0.6.0 <0.8.0;import"./IERC165.sol";
/**
* @dev Implementation of the {IERC165} interface.
*
* Contracts may inherit from this and call {_registerInterface} to declare
* their support of an interface.
*/abstractcontractERC165isIERC165{
/*
* bytes4(keccak256('supportsInterface(bytes4)')) == 0x01ffc9a7
*/bytes4privateconstant _INTERFACE_ID_ERC165 =0x01ffc9a7;
/**
* @dev Mapping of interface ids to whether or not it's supported.
*/mapping(bytes4=>bool) private _supportedInterfaces;
constructor () internal{
// Derived contracts need only register support for their own interfaces,// we register support for ERC165 itself here
_registerInterface(_INTERFACE_ID_ERC165);
}
/**
* @dev See {IERC165-supportsInterface}.
*
* Time complexity O(1), guaranteed to always use less than 30 000 gas.
*/functionsupportsInterface(bytes4 interfaceId) publicviewvirtualoverridereturns (bool) {
return _supportedInterfaces[interfaceId];
}
/**
* @dev Registers the contract as an implementer of the interface defined by
* `interfaceId`. Support of the actual ERC165 interface is automatic and
* registering its interface id is not required.
*
* See {IERC165-supportsInterface}.
*
* Requirements:
*
* - `interfaceId` cannot be the ERC165 invalid interface (`0xffffffff`).
*/function_registerInterface(bytes4 interfaceId) internalvirtual{
require(interfaceId !=0xffffffff, "ERC165: invalid interface id");
_supportedInterfaces[interfaceId] =true;
}
}
Contract Source Code
File 5 of 25: ERC721.sol
// SPDX-License-Identifier: MITpragmasolidity >=0.6.0 <0.8.0;import"../../utils/Context.sol";
import"./IERC721.sol";
import"./IERC721Metadata.sol";
import"./IERC721Enumerable.sol";
import"./IERC721Receiver.sol";
import"../../introspection/ERC165.sol";
import"../../math/SafeMath.sol";
import"../../utils/Address.sol";
import"../../utils/EnumerableSet.sol";
import"../../utils/EnumerableMap.sol";
import"../../utils/Strings.sol";
/**
* @title ERC721 Non-Fungible Token Standard basic implementation
* @dev see https://eips.ethereum.org/EIPS/eip-721
*/contractERC721isContext, ERC165, IERC721, IERC721Metadata, IERC721Enumerable{
usingSafeMathforuint256;
usingAddressforaddress;
usingEnumerableSetforEnumerableSet.UintSet;
usingEnumerableMapforEnumerableMap.UintToAddressMap;
usingStringsforuint256;
// Equals to `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`// which can be also obtained as `IERC721Receiver(0).onERC721Received.selector`bytes4privateconstant _ERC721_RECEIVED =0x150b7a02;
// Mapping from holder address to their (enumerable) set of owned tokensmapping (address=> EnumerableSet.UintSet) private _holderTokens;
// Enumerable mapping from token ids to their owners
EnumerableMap.UintToAddressMap private _tokenOwners;
// Mapping from token ID to approved addressmapping (uint256=>address) private _tokenApprovals;
// Mapping from owner to operator approvalsmapping (address=>mapping (address=>bool)) private _operatorApprovals;
// Token namestringprivate _name;
// Token symbolstringprivate _symbol;
// Optional mapping for token URIsmapping (uint256=>string) private _tokenURIs;
// Base URIstringprivate _baseURI;
/*
* bytes4(keccak256('balanceOf(address)')) == 0x70a08231
* bytes4(keccak256('ownerOf(uint256)')) == 0x6352211e
* bytes4(keccak256('approve(address,uint256)')) == 0x095ea7b3
* bytes4(keccak256('getApproved(uint256)')) == 0x081812fc
* bytes4(keccak256('setApprovalForAll(address,bool)')) == 0xa22cb465
* bytes4(keccak256('isApprovedForAll(address,address)')) == 0xe985e9c5
* bytes4(keccak256('transferFrom(address,address,uint256)')) == 0x23b872dd
* bytes4(keccak256('safeTransferFrom(address,address,uint256)')) == 0x42842e0e
* bytes4(keccak256('safeTransferFrom(address,address,uint256,bytes)')) == 0xb88d4fde
*
* => 0x70a08231 ^ 0x6352211e ^ 0x095ea7b3 ^ 0x081812fc ^
* 0xa22cb465 ^ 0xe985e9c5 ^ 0x23b872dd ^ 0x42842e0e ^ 0xb88d4fde == 0x80ac58cd
*/bytes4privateconstant _INTERFACE_ID_ERC721 =0x80ac58cd;
/*
* bytes4(keccak256('name()')) == 0x06fdde03
* bytes4(keccak256('symbol()')) == 0x95d89b41
* bytes4(keccak256('tokenURI(uint256)')) == 0xc87b56dd
*
* => 0x06fdde03 ^ 0x95d89b41 ^ 0xc87b56dd == 0x5b5e139f
*/bytes4privateconstant _INTERFACE_ID_ERC721_METADATA =0x5b5e139f;
/*
* bytes4(keccak256('totalSupply()')) == 0x18160ddd
* bytes4(keccak256('tokenOfOwnerByIndex(address,uint256)')) == 0x2f745c59
* bytes4(keccak256('tokenByIndex(uint256)')) == 0x4f6ccce7
*
* => 0x18160ddd ^ 0x2f745c59 ^ 0x4f6ccce7 == 0x780e9d63
*/bytes4privateconstant _INTERFACE_ID_ERC721_ENUMERABLE =0x780e9d63;
/**
* @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.
*/constructor (stringmemory name_, stringmemory symbol_) public{
_name = name_;
_symbol = symbol_;
// register the supported interfaces to conform to ERC721 via ERC165
_registerInterface(_INTERFACE_ID_ERC721);
_registerInterface(_INTERFACE_ID_ERC721_METADATA);
_registerInterface(_INTERFACE_ID_ERC721_ENUMERABLE);
}
/**
* @dev See {IERC721-balanceOf}.
*/functionbalanceOf(address owner) publicviewvirtualoverridereturns (uint256) {
require(owner !=address(0), "ERC721: balance query for the zero address");
return _holderTokens[owner].length();
}
/**
* @dev See {IERC721-ownerOf}.
*/functionownerOf(uint256 tokenId) publicviewvirtualoverridereturns (address) {
return _tokenOwners.get(tokenId, "ERC721: owner query for nonexistent token");
}
/**
* @dev See {IERC721Metadata-name}.
*/functionname() publicviewvirtualoverridereturns (stringmemory) {
return _name;
}
/**
* @dev See {IERC721Metadata-symbol}.
*/functionsymbol() publicviewvirtualoverridereturns (stringmemory) {
return _symbol;
}
/**
* @dev See {IERC721Metadata-tokenURI}.
*/functiontokenURI(uint256 tokenId) publicviewvirtualoverridereturns (stringmemory) {
require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");
stringmemory _tokenURI = _tokenURIs[tokenId];
stringmemory base = baseURI();
// If there is no base URI, return the token URI.if (bytes(base).length==0) {
return _tokenURI;
}
// If both are set, concatenate the baseURI and tokenURI (via abi.encodePacked).if (bytes(_tokenURI).length>0) {
returnstring(abi.encodePacked(base, _tokenURI));
}
// If there is a baseURI but no tokenURI, concatenate the tokenID to the baseURI.returnstring(abi.encodePacked(base, tokenId.toString()));
}
/**
* @dev Returns the base URI set via {_setBaseURI}. This will be
* automatically added as a prefix in {tokenURI} to each token's URI, or
* to the token ID if no specific URI is set for that token ID.
*/functionbaseURI() publicviewvirtualreturns (stringmemory) {
return _baseURI;
}
/**
* @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.
*/functiontokenOfOwnerByIndex(address owner, uint256 index) publicviewvirtualoverridereturns (uint256) {
return _holderTokens[owner].at(index);
}
/**
* @dev See {IERC721Enumerable-totalSupply}.
*/functiontotalSupply() publicviewvirtualoverridereturns (uint256) {
// _tokenOwners are indexed by tokenIds, so .length() returns the number of tokenIdsreturn _tokenOwners.length();
}
/**
* @dev See {IERC721Enumerable-tokenByIndex}.
*/functiontokenByIndex(uint256 index) publicviewvirtualoverridereturns (uint256) {
(uint256 tokenId, ) = _tokenOwners.at(index);
return tokenId;
}
/**
* @dev See {IERC721-approve}.
*/functionapprove(address to, uint256 tokenId) publicvirtualoverride{
address owner = ERC721.ownerOf(tokenId);
require(to != owner, "ERC721: approval to current owner");
require(_msgSender() == owner || ERC721.isApprovedForAll(owner, _msgSender()),
"ERC721: approve caller is not owner nor approved for all"
);
_approve(to, tokenId);
}
/**
* @dev See {IERC721-getApproved}.
*/functiongetApproved(uint256 tokenId) publicviewvirtualoverridereturns (address) {
require(_exists(tokenId), "ERC721: approved query for nonexistent token");
return _tokenApprovals[tokenId];
}
/**
* @dev See {IERC721-setApprovalForAll}.
*/functionsetApprovalForAll(address operator, bool approved) publicvirtualoverride{
require(operator != _msgSender(), "ERC721: approve to caller");
_operatorApprovals[_msgSender()][operator] = approved;
emit ApprovalForAll(_msgSender(), operator, approved);
}
/**
* @dev See {IERC721-isApprovedForAll}.
*/functionisApprovedForAll(address owner, address operator) publicviewvirtualoverridereturns (bool) {
return _operatorApprovals[owner][operator];
}
/**
* @dev See {IERC721-transferFrom}.
*/functiontransferFrom(addressfrom, address to, uint256 tokenId) publicvirtualoverride{
//solhint-disable-next-line max-line-lengthrequire(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
_transfer(from, to, tokenId);
}
/**
* @dev See {IERC721-safeTransferFrom}.
*/functionsafeTransferFrom(addressfrom, address to, uint256 tokenId) publicvirtualoverride{
safeTransferFrom(from, to, tokenId, "");
}
/**
* @dev See {IERC721-safeTransferFrom}.
*/functionsafeTransferFrom(addressfrom, address to, uint256 tokenId, bytesmemory _data) publicvirtualoverride{
require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
_safeTransfer(from, to, tokenId, _data);
}
/**
* @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.
*
* `_data` is additional data, it has no specified format and it is sent in call to `to`.
*
* This internal function is equivalent to {safeTransferFrom}, and can be used to e.g.
* implement alternative mechanisms to perform token transfer, such as signature-based.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `tokenId` token must exist and be owned by `from`.
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
*
* Emits a {Transfer} event.
*/function_safeTransfer(addressfrom, address to, uint256 tokenId, bytesmemory _data) internalvirtual{
_transfer(from, to, tokenId);
require(_checkOnERC721Received(from, to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer");
}
/**
* @dev Returns whether `tokenId` exists.
*
* Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
*
* Tokens start existing when they are minted (`_mint`),
* and stop existing when they are burned (`_burn`).
*/function_exists(uint256 tokenId) internalviewvirtualreturns (bool) {
return _tokenOwners.contains(tokenId);
}
/**
* @dev Returns whether `spender` is allowed to manage `tokenId`.
*
* Requirements:
*
* - `tokenId` must exist.
*/function_isApprovedOrOwner(address spender, uint256 tokenId) internalviewvirtualreturns (bool) {
require(_exists(tokenId), "ERC721: operator query for nonexistent token");
address owner = ERC721.ownerOf(tokenId);
return (spender == owner || getApproved(tokenId) == spender || ERC721.isApprovedForAll(owner, spender));
}
/**
* @dev Safely mints `tokenId` and transfers it to `to`.
*
* Requirements:
d*
* - `tokenId` must not exist.
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
*
* Emits a {Transfer} event.
*/function_safeMint(address to, uint256 tokenId) internalvirtual{
_safeMint(to, tokenId, "");
}
/**
* @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is
* forwarded in {IERC721Receiver-onERC721Received} to contract recipients.
*/function_safeMint(address to, uint256 tokenId, bytesmemory _data) internalvirtual{
_mint(to, tokenId);
require(_checkOnERC721Received(address(0), to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer");
}
/**
* @dev Mints `tokenId` and transfers it to `to`.
*
* WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible
*
* Requirements:
*
* - `tokenId` must not exist.
* - `to` cannot be the zero address.
*
* Emits a {Transfer} event.
*/function_mint(address to, uint256 tokenId) internalvirtual{
require(to !=address(0), "ERC721: mint to the zero address");
require(!_exists(tokenId), "ERC721: token already minted");
_beforeTokenTransfer(address(0), to, tokenId);
_holderTokens[to].add(tokenId);
_tokenOwners.set(tokenId, to);
emit Transfer(address(0), to, tokenId);
}
/**
* @dev Destroys `tokenId`.
* The approval is cleared when the token is burned.
*
* Requirements:
*
* - `tokenId` must exist.
*
* Emits a {Transfer} event.
*/function_burn(uint256 tokenId) internalvirtual{
address owner = ERC721.ownerOf(tokenId); // internal owner
_beforeTokenTransfer(owner, address(0), tokenId);
// Clear approvals
_approve(address(0), tokenId);
// Clear metadata (if any)if (bytes(_tokenURIs[tokenId]).length!=0) {
delete _tokenURIs[tokenId];
}
_holderTokens[owner].remove(tokenId);
_tokenOwners.remove(tokenId);
emit Transfer(owner, address(0), tokenId);
}
/**
* @dev Transfers `tokenId` from `from` to `to`.
* As opposed to {transferFrom}, this imposes no restrictions on msg.sender.
*
* Requirements:
*
* - `to` cannot be the zero address.
* - `tokenId` token must be owned by `from`.
*
* Emits a {Transfer} event.
*/function_transfer(addressfrom, address to, uint256 tokenId) internalvirtual{
require(ERC721.ownerOf(tokenId) ==from, "ERC721: transfer of token that is not own"); // internal ownerrequire(to !=address(0), "ERC721: transfer to the zero address");
_beforeTokenTransfer(from, to, tokenId);
// Clear approvals from the previous owner
_approve(address(0), tokenId);
_holderTokens[from].remove(tokenId);
_holderTokens[to].add(tokenId);
_tokenOwners.set(tokenId, to);
emit Transfer(from, to, tokenId);
}
/**
* @dev Sets `_tokenURI` as the tokenURI of `tokenId`.
*
* Requirements:
*
* - `tokenId` must exist.
*/function_setTokenURI(uint256 tokenId, stringmemory _tokenURI) internalvirtual{
require(_exists(tokenId), "ERC721Metadata: URI set of nonexistent token");
_tokenURIs[tokenId] = _tokenURI;
}
/**
* @dev Internal function to set the base URI for all token IDs. It is
* automatically added as a prefix to the value returned in {tokenURI},
* or to the token ID if {tokenURI} is empty.
*/function_setBaseURI(stringmemory baseURI_) internalvirtual{
_baseURI = baseURI_;
}
/**
* @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.
* The call is not executed if the target address is not a contract.
*
* @param from address representing the previous owner of the given token ID
* @param to target address that will receive the tokens
* @param tokenId uint256 ID of the token to be transferred
* @param _data bytes optional data to send along with the call
* @return bool whether the call correctly returned the expected magic value
*/function_checkOnERC721Received(addressfrom, address to, uint256 tokenId, bytesmemory _data)
privatereturns (bool)
{
if (!to.isContract()) {
returntrue;
}
bytesmemory returndata = to.functionCall(abi.encodeWithSelector(
IERC721Receiver(to).onERC721Received.selector,
_msgSender(),
from,
tokenId,
_data
), "ERC721: transfer to non ERC721Receiver implementer");
bytes4 retval =abi.decode(returndata, (bytes4));
return (retval == _ERC721_RECEIVED);
}
/**
* @dev Approve `to` to operate on `tokenId`
*
* Emits an {Approval} event.
*/function_approve(address to, uint256 tokenId) internalvirtual{
_tokenApprovals[tokenId] = to;
emit Approval(ERC721.ownerOf(tokenId), to, tokenId); // internal owner
}
/**
* @dev Hook that is called before any token transfer. This includes minting
* and burning.
*
* Calling conditions:
*
* - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
* transferred to `to`.
* - When `from` is zero, `tokenId` will be minted for `to`.
* - When `to` is zero, ``from``'s `tokenId` will be burned.
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/function_beforeTokenTransfer(addressfrom, address to, uint256 tokenId) internalvirtual{ }
}
Contract Source Code
File 6 of 25: EnumerableMap.sol
// SPDX-License-Identifier: MITpragmasolidity >=0.6.0 <0.8.0;/**
* @dev Library for managing an enumerable variant of Solidity's
* https://solidity.readthedocs.io/en/latest/types.html#mapping-types[`mapping`]
* type.
*
* Maps have the following properties:
*
* - Entries are added, removed, and checked for existence in constant time
* (O(1)).
* - Entries are enumerated in O(n). No guarantees are made on the ordering.
*
* ```
* contract Example {
* // Add the library methods
* using EnumerableMap for EnumerableMap.UintToAddressMap;
*
* // Declare a set state variable
* EnumerableMap.UintToAddressMap private myMap;
* }
* ```
*
* As of v3.0.0, only maps of type `uint256 -> address` (`UintToAddressMap`) are
* supported.
*/libraryEnumerableMap{
// To implement this library for multiple types with as little code// repetition as possible, we write it in terms of a generic Map type with// bytes32 keys and values.// The Map implementation uses private functions, and user-facing// implementations (such as Uint256ToAddressMap) are just wrappers around// the underlying Map.// This means that we can only create new EnumerableMaps for types that fit// in bytes32.structMapEntry {
bytes32 _key;
bytes32 _value;
}
structMap {
// Storage of map keys and values
MapEntry[] _entries;
// Position of the entry defined by a key in the `entries` array, plus 1// because index 0 means a key is not in the map.mapping (bytes32=>uint256) _indexes;
}
/**
* @dev Adds a key-value pair to a map, or updates the value for an existing
* key. O(1).
*
* Returns true if the key was added to the map, that is if it was not
* already present.
*/function_set(Map storage map, bytes32 key, bytes32 value) privatereturns (bool) {
// We read and store the key's index to prevent multiple reads from the same storage slotuint256 keyIndex = map._indexes[key];
if (keyIndex ==0) { // Equivalent to !contains(map, key)
map._entries.push(MapEntry({ _key: key, _value: value }));
// The entry is stored at length-1, but we add 1 to all indexes// and use 0 as a sentinel value
map._indexes[key] = map._entries.length;
returntrue;
} else {
map._entries[keyIndex -1]._value = value;
returnfalse;
}
}
/**
* @dev Removes a key-value pair from a map. O(1).
*
* Returns true if the key was removed from the map, that is if it was present.
*/function_remove(Map storage map, bytes32 key) privatereturns (bool) {
// We read and store the key's index to prevent multiple reads from the same storage slotuint256 keyIndex = map._indexes[key];
if (keyIndex !=0) { // Equivalent to contains(map, key)// To delete a key-value pair from the _entries array in O(1), we swap the entry to delete with the last one// in the array, and then remove the last entry (sometimes called as 'swap and pop').// This modifies the order of the array, as noted in {at}.uint256 toDeleteIndex = keyIndex -1;
uint256 lastIndex = map._entries.length-1;
// When the entry to delete is the last one, the swap operation is unnecessary. However, since this occurs// so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement.
MapEntry storage lastEntry = map._entries[lastIndex];
// Move the last entry to the index where the entry to delete is
map._entries[toDeleteIndex] = lastEntry;
// Update the index for the moved entry
map._indexes[lastEntry._key] = toDeleteIndex +1; // All indexes are 1-based// Delete the slot where the moved entry was stored
map._entries.pop();
// Delete the index for the deleted slotdelete map._indexes[key];
returntrue;
} else {
returnfalse;
}
}
/**
* @dev Returns true if the key is in the map. O(1).
*/function_contains(Map storage map, bytes32 key) privateviewreturns (bool) {
return map._indexes[key] !=0;
}
/**
* @dev Returns the number of key-value pairs in the map. O(1).
*/function_length(Map storage map) privateviewreturns (uint256) {
return map._entries.length;
}
/**
* @dev Returns the key-value pair stored at position `index` in the map. O(1).
*
* Note that there are no guarantees on the ordering of entries inside the
* array, and it may change when more entries are added or removed.
*
* Requirements:
*
* - `index` must be strictly less than {length}.
*/function_at(Map storage map, uint256 index) privateviewreturns (bytes32, bytes32) {
require(map._entries.length> index, "EnumerableMap: index out of bounds");
MapEntry storage entry = map._entries[index];
return (entry._key, entry._value);
}
/**
* @dev Tries to returns the value associated with `key`. O(1).
* Does not revert if `key` is not in the map.
*/function_tryGet(Map storage map, bytes32 key) privateviewreturns (bool, bytes32) {
uint256 keyIndex = map._indexes[key];
if (keyIndex ==0) return (false, 0); // Equivalent to contains(map, key)return (true, map._entries[keyIndex -1]._value); // All indexes are 1-based
}
/**
* @dev Returns the value associated with `key`. O(1).
*
* Requirements:
*
* - `key` must be in the map.
*/function_get(Map storage map, bytes32 key) privateviewreturns (bytes32) {
uint256 keyIndex = map._indexes[key];
require(keyIndex !=0, "EnumerableMap: nonexistent key"); // Equivalent to contains(map, key)return map._entries[keyIndex -1]._value; // All indexes are 1-based
}
/**
* @dev Same as {_get}, with a custom error message when `key` is not in the map.
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {_tryGet}.
*/function_get(Map storage map, bytes32 key, stringmemory errorMessage) privateviewreturns (bytes32) {
uint256 keyIndex = map._indexes[key];
require(keyIndex !=0, errorMessage); // Equivalent to contains(map, key)return map._entries[keyIndex -1]._value; // All indexes are 1-based
}
// UintToAddressMapstructUintToAddressMap {
Map _inner;
}
/**
* @dev Adds a key-value pair to a map, or updates the value for an existing
* key. O(1).
*
* Returns true if the key was added to the map, that is if it was not
* already present.
*/functionset(UintToAddressMap storage map, uint256 key, address value) internalreturns (bool) {
return _set(map._inner, bytes32(key), bytes32(uint256(uint160(value))));
}
/**
* @dev Removes a value from a set. O(1).
*
* Returns true if the key was removed from the map, that is if it was present.
*/functionremove(UintToAddressMap storage map, uint256 key) internalreturns (bool) {
return _remove(map._inner, bytes32(key));
}
/**
* @dev Returns true if the key is in the map. O(1).
*/functioncontains(UintToAddressMap storage map, uint256 key) internalviewreturns (bool) {
return _contains(map._inner, bytes32(key));
}
/**
* @dev Returns the number of elements in the map. O(1).
*/functionlength(UintToAddressMap storage map) internalviewreturns (uint256) {
return _length(map._inner);
}
/**
* @dev Returns the element stored at position `index` in the set. O(1).
* Note that there are no guarantees on the ordering of values inside the
* array, and it may change when more values are added or removed.
*
* Requirements:
*
* - `index` must be strictly less than {length}.
*/functionat(UintToAddressMap storage map, uint256 index) internalviewreturns (uint256, address) {
(bytes32 key, bytes32 value) = _at(map._inner, index);
return (uint256(key), address(uint160(uint256(value))));
}
/**
* @dev Tries to returns the value associated with `key`. O(1).
* Does not revert if `key` is not in the map.
*
* _Available since v3.4._
*/functiontryGet(UintToAddressMap storage map, uint256 key) internalviewreturns (bool, address) {
(bool success, bytes32 value) = _tryGet(map._inner, bytes32(key));
return (success, address(uint160(uint256(value))));
}
/**
* @dev Returns the value associated with `key`. O(1).
*
* Requirements:
*
* - `key` must be in the map.
*/functionget(UintToAddressMap storage map, uint256 key) internalviewreturns (address) {
returnaddress(uint160(uint256(_get(map._inner, bytes32(key)))));
}
/**
* @dev Same as {get}, with a custom error message when `key` is not in the map.
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {tryGet}.
*/functionget(UintToAddressMap storage map, uint256 key, stringmemory errorMessage) internalviewreturns (address) {
returnaddress(uint160(uint256(_get(map._inner, bytes32(key), errorMessage))));
}
}
Contract Source Code
File 7 of 25: EnumerableSet.sol
// SPDX-License-Identifier: MITpragmasolidity >=0.6.0 <0.8.0;/**
* @dev Library for managing
* https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
* types.
*
* Sets have the following properties:
*
* - Elements are added, removed, and checked for existence in constant time
* (O(1)).
* - Elements are enumerated in O(n). No guarantees are made on the ordering.
*
* ```
* contract Example {
* // Add the library methods
* using EnumerableSet for EnumerableSet.AddressSet;
*
* // Declare a set state variable
* EnumerableSet.AddressSet private mySet;
* }
* ```
*
* As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`)
* and `uint256` (`UintSet`) are supported.
*/libraryEnumerableSet{
// To implement this library for multiple types with as little code// repetition as possible, we write it in terms of a generic Set type with// bytes32 values.// The Set implementation uses private functions, and user-facing// implementations (such as AddressSet) are just wrappers around the// underlying Set.// This means that we can only create new EnumerableSets for types that fit// in bytes32.structSet {
// Storage of set valuesbytes32[] _values;
// Position of the value in the `values` array, plus 1 because index 0// means a value is not in the set.mapping (bytes32=>uint256) _indexes;
}
/**
* @dev Add a value to a set. O(1).
*
* Returns true if the value was added to the set, that is if it was not
* already present.
*/function_add(Set storage set, bytes32 value) privatereturns (bool) {
if (!_contains(set, value)) {
set._values.push(value);
// The value is stored at length-1, but we add 1 to all indexes// and use 0 as a sentinel value
set._indexes[value] = set._values.length;
returntrue;
} else {
returnfalse;
}
}
/**
* @dev Removes a value from a set. O(1).
*
* Returns true if the value was removed from the set, that is if it was
* present.
*/function_remove(Set storage set, bytes32 value) privatereturns (bool) {
// We read and store the value's index to prevent multiple reads from the same storage slotuint256 valueIndex = set._indexes[value];
if (valueIndex !=0) { // Equivalent to contains(set, value)// To delete an element from the _values array in O(1), we swap the element to delete with the last one in// the array, and then remove the last element (sometimes called as 'swap and pop').// This modifies the order of the array, as noted in {at}.uint256 toDeleteIndex = valueIndex -1;
uint256 lastIndex = set._values.length-1;
// When the value to delete is the last one, the swap operation is unnecessary. However, since this occurs// so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement.bytes32 lastvalue = set._values[lastIndex];
// Move the last value to the index where the value to delete is
set._values[toDeleteIndex] = lastvalue;
// Update the index for the moved value
set._indexes[lastvalue] = toDeleteIndex +1; // All indexes are 1-based// Delete the slot where the moved value was stored
set._values.pop();
// Delete the index for the deleted slotdelete set._indexes[value];
returntrue;
} else {
returnfalse;
}
}
/**
* @dev Returns true if the value is in the set. O(1).
*/function_contains(Set storage set, bytes32 value) privateviewreturns (bool) {
return set._indexes[value] !=0;
}
/**
* @dev Returns the number of values on the set. O(1).
*/function_length(Set storage set) privateviewreturns (uint256) {
return set._values.length;
}
/**
* @dev Returns the value stored at position `index` in the set. O(1).
*
* Note that there are no guarantees on the ordering of values inside the
* array, and it may change when more values are added or removed.
*
* Requirements:
*
* - `index` must be strictly less than {length}.
*/function_at(Set storage set, uint256 index) privateviewreturns (bytes32) {
require(set._values.length> index, "EnumerableSet: index out of bounds");
return set._values[index];
}
// Bytes32SetstructBytes32Set {
Set _inner;
}
/**
* @dev Add a value to a set. O(1).
*
* Returns true if the value was added to the set, that is if it was not
* already present.
*/functionadd(Bytes32Set storage set, bytes32 value) internalreturns (bool) {
return _add(set._inner, value);
}
/**
* @dev Removes a value from a set. O(1).
*
* Returns true if the value was removed from the set, that is if it was
* present.
*/functionremove(Bytes32Set storage set, bytes32 value) internalreturns (bool) {
return _remove(set._inner, value);
}
/**
* @dev Returns true if the value is in the set. O(1).
*/functioncontains(Bytes32Set storage set, bytes32 value) internalviewreturns (bool) {
return _contains(set._inner, value);
}
/**
* @dev Returns the number of values in the set. O(1).
*/functionlength(Bytes32Set storage set) internalviewreturns (uint256) {
return _length(set._inner);
}
/**
* @dev Returns the value stored at position `index` in the set. O(1).
*
* Note that there are no guarantees on the ordering of values inside the
* array, and it may change when more values are added or removed.
*
* Requirements:
*
* - `index` must be strictly less than {length}.
*/functionat(Bytes32Set storage set, uint256 index) internalviewreturns (bytes32) {
return _at(set._inner, index);
}
// AddressSetstructAddressSet {
Set _inner;
}
/**
* @dev Add a value to a set. O(1).
*
* Returns true if the value was added to the set, that is if it was not
* already present.
*/functionadd(AddressSet storage set, address value) internalreturns (bool) {
return _add(set._inner, bytes32(uint256(uint160(value))));
}
/**
* @dev Removes a value from a set. O(1).
*
* Returns true if the value was removed from the set, that is if it was
* present.
*/functionremove(AddressSet storage set, address value) internalreturns (bool) {
return _remove(set._inner, bytes32(uint256(uint160(value))));
}
/**
* @dev Returns true if the value is in the set. O(1).
*/functioncontains(AddressSet storage set, address value) internalviewreturns (bool) {
return _contains(set._inner, bytes32(uint256(uint160(value))));
}
/**
* @dev Returns the number of values in the set. O(1).
*/functionlength(AddressSet storage set) internalviewreturns (uint256) {
return _length(set._inner);
}
/**
* @dev Returns the value stored at position `index` in the set. O(1).
*
* Note that there are no guarantees on the ordering of values inside the
* array, and it may change when more values are added or removed.
*
* Requirements:
*
* - `index` must be strictly less than {length}.
*/functionat(AddressSet storage set, uint256 index) internalviewreturns (address) {
returnaddress(uint160(uint256(_at(set._inner, index))));
}
// UintSetstructUintSet {
Set _inner;
}
/**
* @dev Add a value to a set. O(1).
*
* Returns true if the value was added to the set, that is if it was not
* already present.
*/functionadd(UintSet storage set, uint256 value) internalreturns (bool) {
return _add(set._inner, bytes32(value));
}
/**
* @dev Removes a value from a set. O(1).
*
* Returns true if the value was removed from the set, that is if it was
* present.
*/functionremove(UintSet storage set, uint256 value) internalreturns (bool) {
return _remove(set._inner, bytes32(value));
}
/**
* @dev Returns true if the value is in the set. O(1).
*/functioncontains(UintSet storage set, uint256 value) internalviewreturns (bool) {
return _contains(set._inner, bytes32(value));
}
/**
* @dev Returns the number of values on the set. O(1).
*/functionlength(UintSet storage set) internalviewreturns (uint256) {
return _length(set._inner);
}
/**
* @dev Returns the value stored at position `index` in the set. O(1).
*
* Note that there are no guarantees on the ordering of values inside the
* array, and it may change when more values are added or removed.
*
* Requirements:
*
* - `index` must be strictly less than {length}.
*/functionat(UintSet storage set, uint256 index) internalviewreturns (uint256) {
returnuint256(_at(set._inner, index));
}
}
Contract Source Code
File 8 of 25: IERC165.sol
// SPDX-License-Identifier: MITpragmasolidity >=0.6.0 <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}.
*/interfaceIERC165{
/**
* @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.
*/functionsupportsInterface(bytes4 interfaceId) externalviewreturns (bool);
}
Contract Source Code
File 9 of 25: IERC20.sol
// SPDX-License-Identifier: MITpragmasolidity >=0.6.0 <0.8.0;/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/interfaceIERC20{
/**
* @dev Returns the amount of tokens in existence.
*/functiontotalSupply() externalviewreturns (uint256);
/**
* @dev Returns the amount of tokens owned by `account`.
*/functionbalanceOf(address account) externalviewreturns (uint256);
/**
* @dev Moves `amount` tokens from the caller's account to `recipient`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/functiontransfer(address recipient, uint256 amount) externalreturns (bool);
/**
* @dev Returns the remaining number of tokens that `spender` will be
* allowed to spend on behalf of `owner` through {transferFrom}. This is
* zero by default.
*
* This value changes when {approve} or {transferFrom} are called.
*/functionallowance(address owner, address spender) externalviewreturns (uint256);
/**
* @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* IMPORTANT: Beware that changing an allowance with this method brings the risk
* that someone may use both the old and the new allowance by unfortunate
* transaction ordering. One possible solution to mitigate this race
* condition is to first reduce the spender's allowance to 0 and set the
* desired value afterwards:
* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
*
* Emits an {Approval} event.
*/functionapprove(address spender, uint256 amount) externalreturns (bool);
/**
* @dev Moves `amount` tokens from `sender` to `recipient` using the
* allowance mechanism. `amount` is then deducted from the caller's
* allowance.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/functiontransferFrom(address sender, address recipient, uint256 amount) externalreturns (bool);
/**
* @dev Emitted when `value` tokens are moved from one account (`from`) to
* another (`to`).
*
* Note that `value` may be zero.
*/eventTransfer(addressindexedfrom, addressindexed to, uint256 value);
/**
* @dev Emitted when the allowance of a `spender` for an `owner` is set by
* a call to {approve}. `value` is the new allowance.
*/eventApproval(addressindexed owner, addressindexed spender, uint256 value);
}
// SPDX-License-Identifier: MITpragmasolidity >=0.6.2 <0.8.0;import"../../introspection/IERC165.sol";
/**
* @dev Required interface of an ERC721 compliant contract.
*/interfaceIERC721isIERC165{
/**
* @dev Emitted when `tokenId` token is transferred from `from` to `to`.
*/eventTransfer(addressindexedfrom, addressindexed to, uint256indexed tokenId);
/**
* @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
*/eventApproval(addressindexed owner, addressindexed approved, uint256indexed tokenId);
/**
* @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
*/eventApprovalForAll(addressindexed owner, addressindexed operator, bool approved);
/**
* @dev Returns the number of tokens in ``owner``'s account.
*/functionbalanceOf(address owner) externalviewreturns (uint256 balance);
/**
* @dev Returns the owner of the `tokenId` token.
*
* Requirements:
*
* - `tokenId` must exist.
*/functionownerOf(uint256 tokenId) externalviewreturns (address owner);
/**
* @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 be 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.
*/functionsafeTransferFrom(addressfrom, address to, uint256 tokenId) external;
/**
* @dev Transfers `tokenId` token from `from` to `to`.
*
* WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
*
* 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.
*/functiontransferFrom(addressfrom, 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.
*/functionapprove(address to, uint256 tokenId) external;
/**
* @dev Returns the account approved for `tokenId` token.
*
* Requirements:
*
* - `tokenId` must exist.
*/functiongetApproved(uint256 tokenId) externalviewreturns (address operator);
/**
* @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.
*/functionsetApprovalForAll(address operator, bool _approved) external;
/**
* @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
*
* See {setApprovalForAll}
*/functionisApprovedForAll(address owner, address operator) externalviewreturns (bool);
/**
* @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.
*/functionsafeTransferFrom(addressfrom, address to, uint256 tokenId, bytescalldata data) external;
}
Contract Source Code
File 12 of 25: IERC721Enumerable.sol
// SPDX-License-Identifier: MITpragmasolidity >=0.6.2 <0.8.0;import"./IERC721.sol";
/**
* @title ERC-721 Non-Fungible Token Standard, optional enumeration extension
* @dev See https://eips.ethereum.org/EIPS/eip-721
*/interfaceIERC721EnumerableisIERC721{
/**
* @dev Returns the total amount of tokens stored by the contract.
*/functiontotalSupply() externalviewreturns (uint256);
/**
* @dev Returns a token ID owned by `owner` at a given `index` of its token list.
* Use along with {balanceOf} to enumerate all of ``owner``'s tokens.
*/functiontokenOfOwnerByIndex(address owner, uint256 index) externalviewreturns (uint256 tokenId);
/**
* @dev Returns a token ID at a given `index` of all the tokens stored by the contract.
* Use along with {totalSupply} to enumerate all tokens.
*/functiontokenByIndex(uint256 index) externalviewreturns (uint256);
}
// SPDX-License-Identifier: MITpragmasolidity >=0.6.0 <0.8.0;/**
* @title ERC721 token receiver interface
* @dev Interface for any contract that wants to support safeTransfers
* from ERC721 asset contracts.
*/interfaceIERC721Receiver{
/**
* @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 `IERC721.onERC721Received.selector`.
*/functiononERC721Received(address operator, addressfrom, uint256 tokenId, bytescalldata data) externalreturns (bytes4);
}
// SPDX-License-Identifier: MITpragmasolidity =0.7.6;import"@openzeppelin/contracts/math/SafeMath.sol";
import"@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
import"@openzeppelin/contracts/token/ERC721/ERC721.sol";
import"@openzeppelin/contracts/utils/Counters.sol";
import"@openzeppelin/contracts/utils/ReentrancyGuard.sol";
import"./interfaces/INFTHandler.sol";
import"./interfaces/IMasterChef.sol";
import"./interfaces/INFTPool.sol";
import"./interfaces/IYieldBooster.sol";
import"./interfaces/tokens/IxARXToken.sol";
import"./interfaces/tokens/IERC20Metadata.sol";
import"./interfaces/INFTPoolRewardManager.sol";
/*
* This contract wraps ERC20 assets into non-fungible staking positions called spNFTs
* spNFTs add the possibility to create an additional layer on liquidity providing lock features
* spNFTs are yield-generating positions when the NFTPool contract has allocations from the MasterChef
*/contractNFTPoolisReentrancyGuard, INFTPool, ERC721("Arbidex staking position NFT", "spNFT") {
usingAddressforaddress;
usingCountersforCounters.Counter;
// using EnumerableSet for EnumerableSet.AddressSet;usingSafeMathforuint256;
usingSafeERC20forIERC20Metadata;
// Info of each NFT (staked position).structStakingPosition {
uint256 amount; // How many lp tokens the user has provideduint256 amountWithMultiplier; // Amount + lock bonus faked amount (amount + amount*multiplier)uint256 startLockTime; // The time at which the user made his deposituint256 lockDuration; // The lock duration in secondsuint256 lockMultiplier; // Active lock multiplier (times 1e2)uint256 rewardDebt; // Reward debtuint256 rewardDebtWETH;
uint256 boostPoints; // Allocated xToken from yieldboost contract (optional)uint256 totalMultiplier; // lockMultiplier + allocated xToken boostPoints multiplieruint256 pendingXTokenRewards; // Not harvested xToken rewardsuint256 pendingArxRewards; // Not harvested ARX rewardsuint256 pendingWETHRewards; // Not harvested ARX rewards
}
Counters.Counter private _tokenIds;
addresspublic operator; // Used to delegate multiplier settings to project's owners
IMasterChef public master; // Address of the masteraddresspublicimmutable factory; // NFTPoolFactory contract's addressboolpublic initialized;
IERC20Metadata private _lpToken; // Deposit token contract's address
IERC20Metadata private _arxToken; // ARXToken contract's address
IxARXToken private _xToken; // xToken contract's address
INFTPoolRewardManager public rewardManager;
uint256private _lpSupply; // Sum of deposit tokens on this pooluint256private _lpSupplyWithMultiplier; // Sum of deposit token on this pool including the user's total multiplier (lockMultiplier + boostPoints)uint256private _accRewardsPerShare; // Accumulated Rewards (staked token) per share, times 1e18. See belowuint256private _accRewardsPerShareWETH;
// readable via getMultiplierSettingsuint256publicconstant MAX_GLOBAL_MULTIPLIER_LIMIT =25000; // 250%, high limit for maxGlobalMultiplier (100 = 1%)uint256publicconstant MAX_LOCK_MULTIPLIER_LIMIT =15000; // 150%, high limit for maxLockMultiplier (100 = 1%)uint256publicconstant MAX_BOOST_MULTIPLIER_LIMIT =15000; // 150%, high limit for maxBoostMultiplier (100 = 1%)uint256private _maxGlobalMultiplier =20000; // 200%uint256private _maxLockDuration =183days; // 6 months, Capped lock duration to have the maximum bonus lockMultiplieruint256private _maxLockMultiplier =10000; // 100%, Max available lockMultiplier (100 = 1%)uint256private _maxBoostMultiplier =10000; // 100%, Max boost that can be earned from xToken yieldBoosteruint256privateconstant _TOTAL_REWARDS_SHARES =10000; // 100%, high limit for xTokenRewardsShareuint256public xTokenRewardsShare =8000; // 80%, directly defines arxShare with the remaining value to 100%boolpublic emergencyUnlock; // Release all locks in case of emergency// readable via getStakingPositionmapping(uint256=> StakingPosition) internal _stakingPositions; // Info of each NFT position that stakes LP tokens/********************************************//****************** EVENTS ******************//********************************************/eventAddToPosition(uint256indexed tokenId, address user, uint256 amount);
eventCreatePosition(uint256indexed tokenId, uint256 amount, uint256 lockDuration);
eventWithdrawFromPosition(uint256indexed tokenId, uint256 amount);
eventEmergencyWithdraw(uint256indexed tokenId, uint256 amount);
eventLockPosition(uint256indexed tokenId, uint256 lockDuration);
eventHarvestPosition(uint256indexed tokenId, address to, uint256 pending, uint256 pendingWETH);
eventSetBoost(uint256indexed tokenId, uint256 boostPoints);
eventPoolUpdated(uint256 lastRewardTime, uint256 accRewardsPerShare, uint256 accRewardsPerShareWETH);
eventSetLockMultiplierSettings(uint256 maxLockDuration, uint256 maxLockMultiplier);
eventSetBoostMultiplierSettings(uint256 maxGlobalMultiplier, uint256 maxBoostMultiplier);
eventSetXTokenRewardsShare(uint256 xTokenRewardsShare);
eventSetUnlockOperator(address operator, bool isAdded);
eventSetEmergencyUnlock(bool emergencyUnlock);
eventSetOperator(address operator);
eventSetRewardManager(address manager);
constructor() {
factory =msg.sender;
}
functioninitialize(
IMasterChef master_,
IERC20Metadata arxToken,
IxARXToken xToken,
IERC20Metadata lpToken,
INFTPoolRewardManager manager
) external{
require(msg.sender== factory &&!initialized, "FORBIDDEN");
_lpToken = lpToken;
master = master_;
_arxToken = arxToken;
_xToken = xToken;
rewardManager = manager;
initialized =true;
// to convert main token to xToken
_arxToken.approve(address(_xToken), type(uint256).max);
}
/***********************************************//****************** MODIFIERS ******************//***********************************************//**
* @dev Check if caller has operator rights
*/function_requireOnlyOwner() internalview{
// require(master.isUnlockOperator(msg.sender), "FORBIDDEN");require(msg.sender== owner(), "FORBIDDEN");
// onlyOwner: caller is not the owner
}
/**
* @dev Check if caller is a validated YieldBooster contract
*/function_requireOnlyYieldBooster() internalview{
// onlyYieldBooster: caller has no yield boost rightsrequire(msg.sender== yieldBooster(), "FORBIDDEN");
}
/**
* @dev Check if a userAddress has privileged rights on a spNFT
*/function_requireOnlyOperatorOrOwnerOf(uint256 tokenId) internalview{
// isApprovedOrOwner: caller has no rights on tokenrequire(ERC721._isApprovedOrOwner(msg.sender, tokenId), "FORBIDDEN");
}
/**
* @dev Check if a userAddress has privileged rights on a spNFT
*/function_requireOnlyApprovedOrOwnerOf(uint256 tokenId) internalview{
require(_exists(tokenId), "ERC721: operator query for nonexistent token");
require(_isOwnerOf(msg.sender, tokenId) || getApproved(tokenId) ==msg.sender, "FORBIDDEN");
}
/**
* @dev Check if a msg.sender is owner of a spNFT
*/function_requireOnlyOwnerOf(uint256 tokenId) internalview{
require(_exists(tokenId), "ERC721: operator query for nonexistent token");
// onlyOwnerOf: caller has no rights on tokenrequire(_isOwnerOf(msg.sender, tokenId), "not owner");
}
/**************************************************//****************** PUBLIC VIEWS ******************//**************************************************//**
* @dev Returns this contract's owner (= master contract's owner)
*/functionowner() publicviewreturns (address) {
return master.owner();
}
/**
* @dev Get master-defined yield booster contract address
*/functionyieldBooster() publicviewreturns (address) {
return master.yieldBooster();
}
/**
* @dev Returns true if "tokenId" is an existing spNFT id
*/functionexists(uint256 tokenId) externalviewoverridereturns (bool) {
return ERC721._exists(tokenId);
}
/**
* @dev Returns last minted NFT id
*/functionlastTokenId() externalviewreturns (uint256) {
return _tokenIds.current();
}
/**
* @dev Returns true if emergency unlocks are activated on this pool or on the master
*/functionisUnlocked() publicviewreturns (bool) {
return emergencyUnlock || master.emergencyUnlock();
}
/**
* @dev Returns true if this pool currently has deposits
*/functionhasDeposits() externalviewoverridereturns (bool) {
return _lpSupplyWithMultiplier >0;
}
/**
* @dev Returns general "pool" info for this contract
*/functiongetPoolInfo()
externalviewoverridereturns (address lpToken,
address arxToken,
address xToken,
uint256 lastRewardTime,
uint256 accRewardsPerShare,
uint256 accRewardsPerShareWETH,
uint256 lpSupply,
uint256 lpSupplyWithMultiplier,
uint256 allocPointsARX,
uint256 allocPointsWETH
)
{
(, allocPointsARX, allocPointsWETH, lastRewardTime, , , , ) = master.getPoolInfo(address(this));
return (
address(_lpToken),
address(_arxToken),
address(_xToken),
lastRewardTime,
_accRewardsPerShare,
_accRewardsPerShareWETH,
_lpSupply,
_lpSupplyWithMultiplier,
allocPointsARX,
allocPointsWETH
);
}
/**
* @dev Returns all multiplier settings for this contract
*/functiongetMultiplierSettings()
externalviewreturns (uint256 maxGlobalMultiplier,
uint256 maxLockDuration,
uint256 maxLockMultiplier,
uint256 maxBoostMultiplier
)
{
return (_maxGlobalMultiplier, _maxLockDuration, _maxLockMultiplier, _maxBoostMultiplier);
}
/**
* @dev Returns bonus multiplier from YieldBooster contract for given "amount" (LP token staked) and "boostPoints" (result is *1e4)
*/functiongetMultiplierByBoostPoints(uint256 amount, uint256 boostPoints) publicviewreturns (uint256) {
if (boostPoints ==0|| amount ==0) return0;
address yieldBoosterAddress = yieldBooster();
// only call yieldBooster contract if defined on masterreturn
yieldBoosterAddress !=address(0)
? IYieldBooster(yieldBoosterAddress).getMultiplier(
address(this),
_maxBoostMultiplier,
amount,
_lpSupply,
boostPoints
)
: 0;
}
/**
* @dev Returns expected multiplier for a "lockDuration" duration lock (result is *1e4)
*/functiongetMultiplierByLockDuration(uint256 lockDuration) publicviewreturns (uint256) {
// in case of emergency unlockif (isUnlocked()) return0;
if (_maxLockDuration ==0|| lockDuration ==0) return0;
// capped to maxLockDurationif (lockDuration >= _maxLockDuration) return _maxLockMultiplier;
return _maxLockMultiplier.mul(lockDuration).div(_maxLockDuration);
}
/**
* @dev Returns a position info
*/functiongetStakingPosition(uint256 tokenId
)
externalviewoverridereturns (uint256 amount,
uint256 amountWithMultiplier,
uint256 startLockTime,
uint256 lockDuration,
uint256 lockMultiplier,
uint256 rewardDebt,
uint256 rewardDebtWETH,
uint256 boostPoints,
uint256 totalMultiplier
)
{
StakingPosition storage position = _stakingPositions[tokenId];
return (
position.amount,
position.amountWithMultiplier,
position.startLockTime,
position.lockDuration,
position.lockMultiplier,
position.rewardDebt,
position.rewardDebtWETH,
position.boostPoints,
position.totalMultiplier
);
}
/**
* @dev Returns pending rewards for a position
*/functionpendingRewards(uint256 tokenId) externalviewreturns (uint256 mainAmount, uint256 wethAmount) {
(
,
,
,
uint256 lastRewardTime,
uint256 reserve,
uint256 reserveWETH,
uint256 poolEmissionRate,
uint256 poolEmissionRateWETH
) = master.getPoolInfo(address(this));
StakingPosition storage position = _stakingPositions[tokenId];
uint256 positionAmountMultiplied = position.amountWithMultiplier;
uint256 accRewardsPerShare = _accRewardsPerShare;
uint256 accRewardsPerShareWETH = _accRewardsPerShareWETH;
bool timeHasPassed = _currentBlockTimestamp() > lastRewardTime;
bool hasLpDeposits = _lpSupplyWithMultiplier >0;
if ((reserve >0|| reserveWETH >0|| timeHasPassed) && hasLpDeposits) {
uint256 duration = _currentBlockTimestamp().sub(lastRewardTime);
// adding reserve here in case master has been synced but not the pooluint256 tokenRewards = duration.mul(poolEmissionRate).add(reserve);
accRewardsPerShare = accRewardsPerShare.add(tokenRewards.mul(1e18).div(_lpSupplyWithMultiplier));
uint256 wethRewards = duration.mul(poolEmissionRateWETH).add(reserveWETH);
accRewardsPerShareWETH = accRewardsPerShareWETH.add(wethRewards.mul(1e18).div(_lpSupplyWithMultiplier));
}
mainAmount = positionAmountMultiplied
.mul(accRewardsPerShare)
.div(1e18)
.sub(position.rewardDebt)
.add(position.pendingXTokenRewards)
.add(position.pendingArxRewards);
wethAmount = positionAmountMultiplied.mul(accRewardsPerShareWETH).div(1e18).sub(position.rewardDebtWETH).add(
position.pendingWETHRewards
);
return (mainAmount, wethAmount);
}
functionpendingAdditionalRewards(uint256 tokenId
) externalviewreturns (address[] memory tokens, uint256[] memory rewardAmounts) {
StakingPosition storage position = _stakingPositions[tokenId];
(, , , uint256 lastRewardTime, , , , ) = master.getPoolInfo(address(this));
(tokens, rewardAmounts) = rewardManager.pendingAdditionalRewards(
tokenId,
position.amountWithMultiplier,
_lpSupplyWithMultiplier,
lastRewardTime
);
}
/*******************************************************//****************** OWNABLE FUNCTIONS ******************//*******************************************************//**
* @dev Set lock multiplier settings
*
* maxLockMultiplier must be <= MAX_LOCK_MULTIPLIER_LIMIT
* maxLockMultiplier must be <= _maxGlobalMultiplier - _maxBoostMultiplier
*
* Must only be called by the owner
*/functionsetLockMultiplierSettings(uint256 maxLockDuration, uint256 maxLockMultiplier) external{
require(msg.sender== owner() ||msg.sender== operator, "FORBIDDEN");
// onlyOperatorOrOwner: caller has no operator rightsrequire(
maxLockMultiplier <= MAX_LOCK_MULTIPLIER_LIMIT &&
maxLockMultiplier.add(_maxBoostMultiplier) <= _maxGlobalMultiplier,
"too high"
);
// setLockSettings: maxGlobalMultiplier is too high
_maxLockDuration = maxLockDuration;
_maxLockMultiplier = maxLockMultiplier;
emit SetLockMultiplierSettings(maxLockDuration, maxLockMultiplier);
}
/**
* @dev Set global and boost multiplier settings
*
* maxGlobalMultiplier must be <= MAX_GLOBAL_MULTIPLIER_LIMIT
* maxBoostMultiplier must be <= MAX_BOOST_MULTIPLIER_LIMIT
* (maxBoostMultiplier + _maxLockMultiplier) must be <= _maxGlobalMultiplier
*
* Must only be called by the owner
*/functionsetBoostMultiplierSettings(uint256 maxGlobalMultiplier, uint256 maxBoostMultiplier) external{
_requireOnlyOwner();
require(maxGlobalMultiplier <= MAX_GLOBAL_MULTIPLIER_LIMIT, "too high");
// setMultiplierSettings: maxGlobalMultiplier is too highrequire(
maxBoostMultiplier <= MAX_BOOST_MULTIPLIER_LIMIT &&
maxBoostMultiplier.add(_maxLockMultiplier) <= maxGlobalMultiplier,
"too high"
);
// setLockSettings: maxGlobalMultiplier is too high
_maxGlobalMultiplier = maxGlobalMultiplier;
_maxBoostMultiplier = maxBoostMultiplier;
emit SetBoostMultiplierSettings(maxGlobalMultiplier, maxBoostMultiplier);
}
/**
* @dev Set the share of xToken for the distributed rewards
* The share of ARX will incidently be 100% - xTokenRewardsShare
*
* Must only be called by the owner
*/functionsetXTokenRewardsShare(uint256 xTokenRewardsShare_) external{
_requireOnlyOwner();
require(xTokenRewardsShare_ <= _TOTAL_REWARDS_SHARES, "too high");
xTokenRewardsShare = xTokenRewardsShare_;
emit SetXTokenRewardsShare(xTokenRewardsShare_);
}
/**
* @dev Set emergency unlock status
*
* Must only be called by the owner
*/functionsetEmergencyUnlock(bool emergencyUnlock_) external{
_requireOnlyOwner();
emergencyUnlock = emergencyUnlock_;
emit SetEmergencyUnlock(emergencyUnlock);
}
/**
* @dev Set operator (usually deposit token's project's owner) to adjust contract's settings
*
* Must only be called by the owner
*/functionsetOperator(address operator_) external{
_requireOnlyOwner();
operator = operator_;
emit SetOperator(operator_);
}
/**
* @dev Set operator (usually deposit token's project's owner) to adjust contract's settings
*
* Must only be called by the owner
*/functionsetRewardManager(address manager) external{
_requireOnlyOwner();
rewardManager = INFTPoolRewardManager(manager);
emit SetRewardManager(manager);
}
/****************************************************************//****************** EXTERNAL PUBLIC FUNCTIONS ******************//****************************************************************//**
* @dev Add nonReentrant to ERC721.transferFrom
*/functiontransferFrom(addressfrom, address to, uint256 tokenId) publicoverride(ERC721, IERC721) nonReentrant{
ERC721.transferFrom(from, to, tokenId);
}
/**
* @dev Add nonReentrant to ERC721.safeTransferFrom
*/functionsafeTransferFrom(addressfrom,
address to,
uint256 tokenId,
bytesmemory _data
) publicoverride(ERC721, IERC721) nonReentrant{
ERC721.safeTransferFrom(from, to, tokenId, _data);
}
/**
* @dev Updates rewards states of the given pool to be up-to-date
*/functionupdatePool() externalnonReentrant{
_updatePool();
}
/**
* @dev Create a staking position (spNFT) with an optional lockDuration
*/functioncreatePosition(uint256 amount, uint256 lockDuration) externalnonReentrant{
// no new lock can be set if the pool has been unlockedif (isUnlocked()) {
require(lockDuration ==0, "locks disabled");
}
_updatePool();
// handle tokens with transfer tax
amount = _transferSupportingFeeOnTransfer(_lpToken, msg.sender, amount);
require(amount !=0, "zero amount"); // createPosition: amount cannot be null// mint NFT position tokenuint256 currentTokenId = _mintNextTokenId(msg.sender);
// calculate bonusesuint256 lockMultiplier = getMultiplierByLockDuration(lockDuration);
uint256 amountWithMultiplier = amount.mul(lockMultiplier.add(1e4)).div(1e4);
// create position
_stakingPositions[currentTokenId] = StakingPosition({
amount: amount,
rewardDebt: amountWithMultiplier.mul(_accRewardsPerShare).div(1e18),
rewardDebtWETH: amountWithMultiplier.mul(_accRewardsPerShareWETH).div(1e18),
lockDuration: lockDuration,
startLockTime: _currentBlockTimestamp(),
lockMultiplier: lockMultiplier,
amountWithMultiplier: amountWithMultiplier,
boostPoints: 0,
totalMultiplier: lockMultiplier,
pendingArxRewards: 0,
pendingXTokenRewards: 0,
pendingWETHRewards: 0
});
// update total lp supply
_lpSupply = _lpSupply.add(amount);
_lpSupplyWithMultiplier = _lpSupplyWithMultiplier.add(amountWithMultiplier);
rewardManager.updatePositionRewardDebts(amountWithMultiplier, currentTokenId);
emit CreatePosition(currentTokenId, amount, lockDuration);
}
/**
* @dev Add to an existing staking position
*
* Can only be called by spNFT's owner or operators
*/functionaddToPosition(uint256 tokenId, uint256 amountToAdd) externalnonReentrant{
_requireOnlyOperatorOrOwnerOf(tokenId);
require(amountToAdd >0, "0 amount"); // addToPosition: amount cannot be null
_updatePool();
address nftOwner = ERC721.ownerOf(tokenId);
_harvestPosition(tokenId, nftOwner);
StakingPosition storage position = _stakingPositions[tokenId];
// if position is locked, renew the lockif (position.lockDuration >0) {
position.startLockTime = _currentBlockTimestamp();
position.lockMultiplier = getMultiplierByLockDuration(position.lockDuration);
}
// handle tokens with transfer tax
amountToAdd = _transferSupportingFeeOnTransfer(_lpToken, msg.sender, amountToAdd);
// update position
position.amount = position.amount.add(amountToAdd);
_lpSupply = _lpSupply.add(amountToAdd);
_updateBoostMultiplierInfoAndRewardDebt(position, tokenId);
_checkOnAddToPosition(nftOwner, tokenId, amountToAdd);
emit AddToPosition(tokenId, msg.sender, amountToAdd);
}
/**
* @dev Assign "amount" of boost points to a position
*
* Can only be called by the master-defined YieldBooster contract
*/functionboost(uint256 tokenId, uint256 amount) externaloverridenonReentrant{
_requireOnlyYieldBooster();
require(ERC721._exists(tokenId), "invalid tokenId");
_updatePool();
_harvestPosition(tokenId, address(0));
StakingPosition storage position = _stakingPositions[tokenId];
// update positionuint256 boostPoints = position.boostPoints.add(amount);
position.boostPoints = boostPoints;
_updateBoostMultiplierInfoAndRewardDebt(position, tokenId);
emit SetBoost(tokenId, boostPoints);
}
/**
* @dev Remove "amount" of boost points from a position
*
* Can only be called by the master-defined YieldBooster contract
*/functionunboost(uint256 tokenId, uint256 amount) externaloverridenonReentrant{
_requireOnlyYieldBooster();
_updatePool();
_harvestPosition(tokenId, address(0));
StakingPosition storage position = _stakingPositions[tokenId];
// update positionuint256 boostPoints = position.boostPoints.sub(amount);
position.boostPoints = boostPoints;
_updateBoostMultiplierInfoAndRewardDebt(position, tokenId);
emit SetBoost(tokenId, boostPoints);
}
/**
* @dev Harvest from a staking position
*
* Can only be called by spNFT's owner or approved address
*/functionharvestPosition(uint256 tokenId) externalnonReentrant{
_requireOnlyApprovedOrOwnerOf(tokenId);
_updatePool();
_harvestPosition(tokenId, ERC721.ownerOf(tokenId));
_updateBoostMultiplierInfoAndRewardDebt(_stakingPositions[tokenId], tokenId);
}
/**
* @dev Harvest from a staking position to "to" address
*
* Can only be called by spNFT's owner or approved address
* spNFT's owner must be a contract
*/functionharvestPositionTo(uint256 tokenId, address to) externalnonReentrant{
_requireOnlyApprovedOrOwnerOf(tokenId);
require(ERC721.ownerOf(tokenId).isContract(), "FORBIDDEN");
_updatePool();
_harvestPosition(tokenId, to);
_updateBoostMultiplierInfoAndRewardDebt(_stakingPositions[tokenId], tokenId);
}
/**
* @dev Harvest from multiple staking positions to "to" address
*
* Can only be called by spNFT's owner or approved address
*/functionharvestPositionsTo(uint256[] calldata tokenIds, address to) externalnonReentrant{
_updatePool();
uint256 length = tokenIds.length;
for (uint256 i =0; i < length; ++i) {
uint256 tokenId = tokenIds[i];
_requireOnlyApprovedOrOwnerOf(tokenId);
address tokenOwner = ERC721.ownerOf(tokenId);
// if sender is the current owner, must also be the harvest dst address// if sender is approved, current owner must be a contractrequire((msg.sender== tokenOwner &&msg.sender== to) || tokenOwner.isContract(), "FORBIDDEN");
_harvestPosition(tokenId, to);
_updateBoostMultiplierInfoAndRewardDebt(_stakingPositions[tokenId], tokenId);
}
}
/**
* @dev Withdraw from a staking position
*
* Can only be called by spNFT's owner or approved address
*/functionwithdrawFromPosition(uint256 tokenId, uint256 amountToWithdraw) externalnonReentrant{
_requireOnlyApprovedOrOwnerOf(tokenId);
_updatePool();
address nftOwner = ERC721.ownerOf(tokenId);
_withdrawFromPosition(nftOwner, tokenId, amountToWithdraw);
_checkOnWithdraw(nftOwner, tokenId, amountToWithdraw);
}
/**
* @dev Renew lock from a staking position
*
* Can only be called by spNFT's owner or approved address
*/functionrenewLockPosition(uint256 tokenId) externalnonReentrant{
_requireOnlyApprovedOrOwnerOf(tokenId);
_updatePool();
_lockPosition(tokenId, _stakingPositions[tokenId].lockDuration);
}
/**
* @dev Lock a staking position (can be used to extend a lock)
*
* Can only be called by spNFT's owner or approved address
*/functionlockPosition(uint256 tokenId, uint256 lockDuration) externalnonReentrant{
_requireOnlyApprovedOrOwnerOf(tokenId);
_updatePool();
_lockPosition(tokenId, lockDuration);
}
/**
* Withdraw without caring about rewards, EMERGENCY ONLY
*
* Can only be called by spNFT's owner
*/functionemergencyWithdraw(uint256 tokenId) externalnonReentrant{
_requireOnlyOwnerOf(tokenId);
StakingPosition storage position = _stakingPositions[tokenId];
require(
master.isUnlockOperator(msg.sender) ||
position.startLockTime.add(position.lockDuration) <= _currentBlockTimestamp() ||
isUnlocked(),
"locked"
);
// emergencyWithdraw: lockeduint256 amount = position.amount;
// update total lp supply
_lpSupply = _lpSupply.sub(amount);
_lpSupplyWithMultiplier = _lpSupplyWithMultiplier.sub(position.amountWithMultiplier);
// destroy position (ignore boost points)
_destroyPosition(tokenId, 0);
emit EmergencyWithdraw(tokenId, amount);
_lpToken.safeTransfer(msg.sender, amount);
}
/********************************************************//****************** INTERNAL FUNCTIONS ******************//********************************************************//**
* @dev Returns whether "userAddress" is the owner of "tokenId" spNFT
*/function_isOwnerOf(address userAddress, uint256 tokenId) internalviewreturns (bool) {
return userAddress == ERC721.ownerOf(tokenId);
}
/**
* @dev Updates rewards states of this pool to be up-to-date
*/function_updatePool() internal{
uint256 lpSupplyMultiplied = _lpSupplyWithMultiplier; // stash// User current reward time before pool claims and updates it
(, , , uint256 currentLastRewardTime, , , , ) = master.getPoolInfo(address(this));
rewardManager.updateRewardsPerShare(lpSupplyMultiplied, currentLastRewardTime);
// Returns the amount of main token and WETH. Both amounts are transfered to this contract at this time
(uint256 rewardAmount, uint256 amountWETH) = master.claimRewards();
if (rewardAmount >0) {
_accRewardsPerShare = _accRewardsPerShare.add(rewardAmount.mul(1e18).div(lpSupplyMultiplied));
}
if (amountWETH >0) {
_accRewardsPerShareWETH = _accRewardsPerShareWETH.add(amountWETH.mul(1e18).div(lpSupplyMultiplied));
}
emit PoolUpdated(_currentBlockTimestamp(), _accRewardsPerShare, _accRewardsPerShareWETH);
}
/**
* @dev Destroys spNFT
*
* "boostPointsToDeallocate" is set to 0 to ignore boost points handling if called during an emergencyWithdraw
* Users should still be able to deallocate xToken from the YieldBooster contract
*/function_destroyPosition(uint256 tokenId, uint256 boostPoints) internal{
// calls yieldBooster contract to deallocate the spNFT's owner boost points if anyif (boostPoints >0) {
IYieldBooster(yieldBooster()).deallocateAllFromPool(msg.sender, tokenId);
}
// burn spNFTdelete _stakingPositions[tokenId];
ERC721._burn(tokenId);
}
/**
* @dev Computes new tokenId and mint associated spNFT to "to" address
*/function_mintNextTokenId(address to) internalreturns (uint256 tokenId) {
_tokenIds.increment();
tokenId = _tokenIds.current();
_safeMint(to, tokenId);
}
/**
* @dev Withdraw from a staking position and destroy it
*
* _updatePool() should be executed before calling this
*/function_withdrawFromPosition(address nftOwner, uint256 tokenId, uint256 amountToWithdraw) internal{
require(amountToWithdraw >0, "null");
// withdrawFromPosition: amount cannot be null
StakingPosition storage position = _stakingPositions[tokenId];
require(
master.isUnlockOperator(nftOwner) ||
position.startLockTime.add(position.lockDuration) <= _currentBlockTimestamp() ||
isUnlocked(),
"locked"
);
// withdrawFromPosition: invalid amountrequire(position.amount >= amountToWithdraw, "invalid");
_harvestPosition(tokenId, nftOwner);
// update position
position.amount = position.amount.sub(amountToWithdraw);
// update total lp supply
_lpSupply = _lpSupply.sub(amountToWithdraw);
if (position.amount ==0) {
// destroy if now empty
_lpSupplyWithMultiplier = _lpSupplyWithMultiplier.sub(position.amountWithMultiplier);
_destroyPosition(tokenId, position.boostPoints);
} else {
_updateBoostMultiplierInfoAndRewardDebt(position, tokenId);
}
emit WithdrawFromPosition(tokenId, amountToWithdraw);
_lpToken.safeTransfer(nftOwner, amountToWithdraw);
}
/**
* @dev updates position's boost multiplier, totalMultiplier, amountWithMultiplier (_lpSupplyWithMultiplier)
* and rewardDebt without updating lockMultiplier
*/function_updateBoostMultiplierInfoAndRewardDebt(StakingPosition storage position, uint256 tokenId) internal{
// keep the original lock multiplier and recompute current boostPoints multiplieruint256 newTotalMultiplier = getMultiplierByBoostPoints(position.amount, position.boostPoints).add(
position.lockMultiplier
);
if (newTotalMultiplier > _maxGlobalMultiplier) newTotalMultiplier = _maxGlobalMultiplier;
position.totalMultiplier = newTotalMultiplier;
uint256 amountWithMultiplier = position.amount.mul(newTotalMultiplier.add(1e4)).div(1e4);
uint256 lpSupplyMultiplied = _lpSupplyWithMultiplier;
// update global supply
_lpSupplyWithMultiplier = lpSupplyMultiplied.sub(position.amountWithMultiplier).add(amountWithMultiplier);
position.amountWithMultiplier = amountWithMultiplier;
position.rewardDebt = amountWithMultiplier.mul(_accRewardsPerShare).div(1e18);
position.rewardDebtWETH = amountWithMultiplier.mul(_accRewardsPerShareWETH).div(1e18);
rewardManager.updatePositionRewardDebts(amountWithMultiplier, tokenId);
}
/**
* @dev Harvest rewards from a position
* Will also update the position's totalMultiplier
*/function_harvestPosition(uint256 tokenId, address to) internal{
StakingPosition storage position = _stakingPositions[tokenId];
// compute position's pending rewardsuint256 positionAmountMultiplied = position.amountWithMultiplier;
uint256 pending = positionAmountMultiplied.mul(_accRewardsPerShare).div(1e18).sub(position.rewardDebt);
uint256 pendingWETH = positionAmountMultiplied.mul(_accRewardsPerShareWETH).div(1e18).sub(
position.rewardDebtWETH
);
// unlock the position if pool has been unlocked or position is unlockedif (isUnlocked() || position.startLockTime.add(position.lockDuration) <= _currentBlockTimestamp()) {
position.lockDuration =0;
position.lockMultiplier =0;
}
// transfer rewardsif (
pending >0||
pendingWETH >0||
position.pendingXTokenRewards >0||
position.pendingArxRewards >0||
position.pendingWETHRewards >0
) {
uint256 xTokenRewards = pending.mul(xTokenRewardsShare).div(_TOTAL_REWARDS_SHARES);
uint256 arxAmount = pending.add(position.pendingArxRewards).sub(xTokenRewards);
xTokenRewards = xTokenRewards.add(position.pendingXTokenRewards);
// Stack rewards in a buffer if to is equal to address(0)if (address(0) == to) {
position.pendingXTokenRewards = xTokenRewards;
position.pendingArxRewards = arxAmount;
position.pendingWETHRewards = pendingWETH;
} else {
// convert and send xToken + main token rewards
position.pendingXTokenRewards =0;
position.pendingArxRewards =0;
position.pendingWETHRewards =0;
if (xTokenRewards >0) xTokenRewards = _safeConvertTo(to, xTokenRewards);
arxAmount = _safeRewardsTransfer(address(_arxToken), to, arxAmount);
pendingWETH = _safeRewardsTransfer(master.wethToken(), to, pendingWETH);
// forbidden to harvest if contract has not explicitly confirmed it handle it
_checkOnNFTHarvest(to, tokenId, arxAmount, xTokenRewards);
rewardManager.harvestAdditionalRewards(positionAmountMultiplied, to, tokenId);
}
}
emit HarvestPosition(tokenId, to, pending, pendingWETH);
}
/**
* @dev Renew lock from a staking position with "lockDuration"
*/function_lockPosition(uint256 tokenId, uint256 lockDuration) internal{
require(!isUnlocked(), "locks disabled");
StakingPosition storage position = _stakingPositions[tokenId];
// for renew only, check if new lockDuration is at least = to the remaining active durationuint256 endTime = position.startLockTime.add(position.lockDuration);
uint256 currentBlockTimestamp = _currentBlockTimestamp();
if (endTime > currentBlockTimestamp) {
require(lockDuration >= endTime.sub(currentBlockTimestamp) && lockDuration >0, "invalid");
}
_harvestPosition(tokenId, msg.sender);
// update position and total lp supply
position.lockDuration = lockDuration;
position.lockMultiplier = getMultiplierByLockDuration(lockDuration);
position.startLockTime = currentBlockTimestamp;
_updateBoostMultiplierInfoAndRewardDebt(position, tokenId);
emit LockPosition(tokenId, lockDuration);
}
/**
* @dev Handle deposits of tokens with transfer tax
*/function_transferSupportingFeeOnTransfer(
IERC20Metadata token,
address user,
uint256 amount
) internalreturns (uint256 receivedAmount) {
uint256 previousBalance = token.balanceOf(address(this));
token.safeTransferFrom(user, address(this), amount);
return token.balanceOf(address(this)).sub(previousBalance);
}
/**
* @dev Safe token transfer function, in case rounding error causes pool to not have enough tokens
*/function_safeRewardsTransfer(address tokenAddress, address to, uint256 amount) internalreturns (uint256) {
IERC20Metadata token = IERC20Metadata(tokenAddress);
uint256 balance = token.balanceOf(address(this));
// cap to available balanceif (amount > balance) {
amount = balance;
}
if (amount >0) {
token.safeTransfer(to, amount);
}
return amount;
}
/**
* @dev Safe convert ARX to xToken function, in case rounding error causes pool to not have enough tokens
*/function_safeConvertTo(address to, uint256 amount) internalreturns (uint256) {
uint256 balance = _arxToken.balanceOf(address(this));
// cap to available balanceif (amount > balance) {
amount = balance;
}
if (amount >0) _xToken.convertTo(amount, to);
return amount;
}
/**
* @dev If NFT's owner is a contract, confirm whether it's able to handle rewards harvesting
*/function_checkOnNFTHarvest(address to, uint256 tokenId, uint256 arxAmount, uint256 xTokenAmount) internal{
address nftOwner = ERC721.ownerOf(tokenId);
if (nftOwner.isContract()) {
bytesmemory returndata = nftOwner.functionCall(
abi.encodeWithSelector(
INFTHandler(nftOwner).onNFTHarvest.selector,
msg.sender,
to,
tokenId,
arxAmount,
xTokenAmount
),
"non implemented"
);
require(abi.decode(returndata, (bool)), "FORBIDDEN");
}
}
/**
* @dev If NFT's owner is a contract, confirm whether it's able to handle addToPosition
*/function_checkOnAddToPosition(address nftOwner, uint256 tokenId, uint256 lpAmount) internal{
if (nftOwner.isContract()) {
bytesmemory returndata = nftOwner.functionCall(
abi.encodeWithSelector(
INFTHandler(nftOwner).onNFTAddToPosition.selector,
msg.sender,
tokenId,
lpAmount
),
"non implemented"
);
require(abi.decode(returndata, (bool)), "FORBIDDEN");
}
}
/**
* @dev If NFT's owner is a contract, confirm whether it's able to handle withdrawals
*/function_checkOnWithdraw(address nftOwner, uint256 tokenId, uint256 lpAmount) internal{
if (nftOwner.isContract()) {
bytesmemory returndata = nftOwner.functionCall(
abi.encodeWithSelector(INFTHandler(nftOwner).onNFTWithdraw.selector, msg.sender, tokenId, lpAmount),
"non implemented"
);
require(abi.decode(returndata, (bool)), "FORBIDDEN");
}
}
/**
* @dev Forbid transfer when spNFT's owner is a contract and an operator is trying to transfer it
* This is made to avoid unintended side effects
*
* Contract owner can still implement it by itself if needed
*/function_beforeTokenTransfer(addressfrom, address/*to*/, uint256/*tokenId*/) internalviewoverride{
require(!from.isContract() ||msg.sender==from, "FORBIDDEN");
}
/**
* @dev Utility function to get the current block timestamp
*/function_currentBlockTimestamp() internalviewvirtualreturns (uint256) {
/* solhint-disable not-rely-on-time */returnblock.timestamp;
}
}
Contract Source Code
File 22 of 25: ReentrancyGuard.sol
// SPDX-License-Identifier: MITpragmasolidity >=0.6.0 <0.8.0;/**
* @dev Contract module that helps prevent reentrant calls to a function.
*
* Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
* available, which can be applied to functions to make sure there are no nested
* (reentrant) calls to them.
*
* Note that because there is a single `nonReentrant` guard, functions marked as
* `nonReentrant` may not call one another. This can be worked around by making
* those functions `private`, and then adding `external` `nonReentrant` entry
* points to them.
*
* TIP: If you would like to learn more about reentrancy and alternative ways
* to protect against it, check out our blog post
* https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
*/abstractcontractReentrancyGuard{
// Booleans are more expensive than uint256 or any type that takes up a full// word because each write operation emits an extra SLOAD to first read the// slot's contents, replace the bits taken up by the boolean, and then write// back. This is the compiler's defense against contract upgrades and// pointer aliasing, and it cannot be disabled.// The values being non-zero value makes deployment a bit more expensive,// but in exchange the refund on every call to nonReentrant will be lower in// amount. Since refunds are capped to a percentage of the total// transaction's gas, it is best to keep them low in cases like this one, to// increase the likelihood of the full refund coming into effect.uint256privateconstant _NOT_ENTERED =1;
uint256privateconstant _ENTERED =2;
uint256private _status;
constructor () internal{
_status = _NOT_ENTERED;
}
/**
* @dev Prevents a contract from calling itself, directly or indirectly.
* Calling a `nonReentrant` function from another `nonReentrant`
* function is not supported. It is possible to prevent this from happening
* by making the `nonReentrant` function external, and make it call a
* `private` function that does the actual work.
*/modifiernonReentrant() {
// On the first call to nonReentrant, _notEntered will be truerequire(_status != _ENTERED, "ReentrancyGuard: reentrant call");
// Any calls to nonReentrant after this point will fail
_status = _ENTERED;
_;
// By storing the original value once again, a refund is triggered (see// https://eips.ethereum.org/EIPS/eip-2200)
_status = _NOT_ENTERED;
}
}
Contract Source Code
File 23 of 25: SafeERC20.sol
// SPDX-License-Identifier: MITpragmasolidity >=0.6.0 <0.8.0;import"./IERC20.sol";
import"../../math/SafeMath.sol";
import"../../utils/Address.sol";
/**
* @title SafeERC20
* @dev Wrappers around ERC20 operations that throw on failure (when the token
* contract returns false). Tokens that return no value (and instead revert or
* throw on failure) are also supported, non-reverting calls are assumed to be
* successful.
* To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
* which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
*/librarySafeERC20{
usingSafeMathforuint256;
usingAddressforaddress;
functionsafeTransfer(IERC20 token, address to, uint256 value) internal{
_callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
}
functionsafeTransferFrom(IERC20 token, addressfrom, address to, uint256 value) internal{
_callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
}
/**
* @dev Deprecated. This function has issues similar to the ones found in
* {IERC20-approve}, and its usage is discouraged.
*
* Whenever possible, use {safeIncreaseAllowance} and
* {safeDecreaseAllowance} instead.
*/functionsafeApprove(IERC20 token, address spender, uint256 value) internal{
// safeApprove should only be called when setting an initial allowance,// or when resetting it to zero. To increase and decrease it, use// 'safeIncreaseAllowance' and 'safeDecreaseAllowance'// solhint-disable-next-line max-line-lengthrequire((value ==0) || (token.allowance(address(this), spender) ==0),
"SafeERC20: approve from non-zero to non-zero allowance"
);
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
}
functionsafeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal{
uint256 newAllowance = token.allowance(address(this), spender).add(value);
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
functionsafeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal{
uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
/**
* @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
* on the return value: the return value is optional (but if data is returned, it must not be false).
* @param token The token targeted by the call.
* @param data The call data (encoded using abi.encode or one of its variants).
*/function_callOptionalReturn(IERC20 token, bytesmemory data) private{
// We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since// we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that// the target address contains contract code and also asserts for success in the low-level call.bytesmemory returndata =address(token).functionCall(data, "SafeERC20: low-level call failed");
if (returndata.length>0) { // Return data is optional// solhint-disable-next-line max-line-lengthrequire(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
}
}
}
Contract Source Code
File 24 of 25: SafeMath.sol
// SPDX-License-Identifier: MITpragmasolidity >=0.6.0 <0.8.0;/**
* @dev Wrappers over Solidity's arithmetic operations with added overflow
* checks.
*
* Arithmetic operations in Solidity wrap on overflow. This can easily result
* in bugs, because programmers usually assume that an overflow raises an
* error, which is the standard behavior in high level programming languages.
* `SafeMath` restores this intuition by reverting the transaction when an
* operation overflows.
*
* Using this library instead of the unchecked operations eliminates an entire
* class of bugs, so it's recommended to use it always.
*/librarySafeMath{
/**
* @dev Returns the addition of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/functiontryAdd(uint256 a, uint256 b) internalpurereturns (bool, uint256) {
uint256 c = a + b;
if (c < a) return (false, 0);
return (true, c);
}
/**
* @dev Returns the substraction of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/functiontrySub(uint256 a, uint256 b) internalpurereturns (bool, uint256) {
if (b > a) return (false, 0);
return (true, a - b);
}
/**
* @dev Returns the multiplication of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/functiontryMul(uint256 a, uint256 b) internalpurereturns (bool, uint256) {
// Gas optimization: this is cheaper than requiring 'a' not being zero, but the// benefit is lost if 'b' is also tested.// See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522if (a ==0) return (true, 0);
uint256 c = a * b;
if (c / a != b) return (false, 0);
return (true, c);
}
/**
* @dev Returns the division of two unsigned integers, with a division by zero flag.
*
* _Available since v3.4._
*/functiontryDiv(uint256 a, uint256 b) internalpurereturns (bool, uint256) {
if (b ==0) return (false, 0);
return (true, a / b);
}
/**
* @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
*
* _Available since v3.4._
*/functiontryMod(uint256 a, uint256 b) internalpurereturns (bool, uint256) {
if (b ==0) return (false, 0);
return (true, a % b);
}
/**
* @dev Returns the addition of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `+` operator.
*
* Requirements:
*
* - Addition cannot overflow.
*/functionadd(uint256 a, uint256 b) internalpurereturns (uint256) {
uint256 c = a + b;
require(c >= a, "SafeMath: addition overflow");
return c;
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting on
* overflow (when the result is negative).
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
*
* - Subtraction cannot overflow.
*/functionsub(uint256 a, uint256 b) internalpurereturns (uint256) {
require(b <= a, "SafeMath: subtraction overflow");
return a - b;
}
/**
* @dev Returns the multiplication of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `*` operator.
*
* Requirements:
*
* - Multiplication cannot overflow.
*/functionmul(uint256 a, uint256 b) internalpurereturns (uint256) {
if (a ==0) return0;
uint256 c = a * b;
require(c / a == b, "SafeMath: multiplication overflow");
return c;
}
/**
* @dev Returns the integer division of two unsigned integers, reverting on
* division by zero. The result is rounded towards zero.
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/functiondiv(uint256 a, uint256 b) internalpurereturns (uint256) {
require(b >0, "SafeMath: division by zero");
return a / b;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* reverting when dividing by zero.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/functionmod(uint256 a, uint256 b) internalpurereturns (uint256) {
require(b >0, "SafeMath: modulo by zero");
return a % b;
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting with custom message on
* overflow (when the result is negative).
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {trySub}.
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
*
* - Subtraction cannot overflow.
*/functionsub(uint256 a, uint256 b, stringmemory errorMessage) internalpurereturns (uint256) {
require(b <= a, errorMessage);
return a - b;
}
/**
* @dev Returns the integer division of two unsigned integers, reverting with custom message on
* division by zero. The result is rounded towards zero.
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {tryDiv}.
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/functiondiv(uint256 a, uint256 b, stringmemory errorMessage) internalpurereturns (uint256) {
require(b >0, errorMessage);
return a / b;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* reverting with custom message when dividing by zero.
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {tryMod}.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/functionmod(uint256 a, uint256 b, stringmemory errorMessage) internalpurereturns (uint256) {
require(b >0, errorMessage);
return a % b;
}
}
Contract Source Code
File 25 of 25: Strings.sol
// SPDX-License-Identifier: MITpragmasolidity >=0.6.0 <0.8.0;/**
* @dev String operations.
*/libraryStrings{
/**
* @dev Converts a `uint256` to its ASCII `string` representation.
*/functiontoString(uint256 value) internalpurereturns (stringmemory) {
// Inspired by OraclizeAPI's implementation - MIT licence// https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.solif (value ==0) {
return"0";
}
uint256 temp = value;
uint256 digits;
while (temp !=0) {
digits++;
temp /=10;
}
bytesmemory buffer =newbytes(digits);
uint256 index = digits -1;
temp = value;
while (temp !=0) {
buffer[index--] =bytes1(uint8(48+ temp %10));
temp /=10;
}
returnstring(buffer);
}
}