const format = require('../format-lines');
const { fromBytes32, toBytes32 } = require('./conversion');
const TYPES = [
{ name: 'Bytes32Set', type: 'bytes32' },
{ name: 'AddressSet', type: 'address' },
{ name: 'UintSet', type: 'uint256' },
];
const header = `\
pragma solidity ^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.
*
* \`\`\`solidity
* 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.
*
* [WARNING]
* ====
* Trying to delete such a structure from storage will likely result in data corruption, rendering the structure
* unusable.
* See https://github.com/ethereum/solidity/pull/11843[ethereum/solidity#11843] for more info.
*
* In order to clean an EnumerableSet, you can either remove all elements one by one or create a fresh instance using an
* array of EnumerableSet.
* ====
*/
`;
const defaultSet = () => `\
// 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.
struct Set {
// Storage of set values
bytes32[] _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) private returns (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;
return true;
} else {
return false;
}
}
/**
* @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) private returns (bool) {
// We read and store the value's index to prevent multiple reads from the same storage slot
uint256 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;
if (lastIndex != toDeleteIndex) {
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] = valueIndex; // Replace lastValue's index to valueIndex
}
// Delete the slot where the moved value was stored
set._values.pop();
// Delete the index for the deleted slot
delete set._indexes[value];
return true;
} else {
return false;
}
}
/**
* @dev Returns true if the value is in the set. O(1).
*/
function _contains(Set storage set, bytes32 value) private view returns (bool) {
return set._indexes[value] != 0;
}
/**
* @dev Returns the number of values on the set. O(1).
*/
function _length(Set storage set) private view returns (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) private view returns (bytes32) {
return set._values[index];
}
/**
* @dev Return the entire set in an array
*
* WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
* to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
* this function has an unbounded cost, and using it as part of a state-changing function may render the function
* uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
*/
function _values(Set storage set) private view returns (bytes32[] memory) {
return set._values;
}
`;
const customSet = ({ name, type }) => `\
// ${name}
struct ${name} {
Set _inner;
}
/**
* @dev Add a value to a set. O(1).
*
* Returns true if the value was added to the set, that is if it was not
* already present.
*/
function add(${name} storage set, ${type} value) internal returns (bool) {
return _add(set._inner, ${toBytes32(type, 'value')});
}
/**
* @dev Removes a value from a set. O(1).
*
* Returns true if the value was removed from the set, that is if it was
* present.
*/
function remove(${name} storage set, ${type} value) internal returns (bool) {
return _remove(set._inner, ${toBytes32(type, 'value')});
}
/**
* @dev Returns true if the value is in the set. O(1).
*/
function contains(${name} storage set, ${type} value) internal view returns (bool) {
return _contains(set._inner, ${toBytes32(type, 'value')});
}
/**
* @dev Returns the number of values in the set. O(1).
*/
function length(${name} storage set) internal view returns (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}.
*/
function at(${name} storage set, uint256 index) internal view returns (${type}) {
return ${fromBytes32(type, '_at(set._inner, index)')};
}
/**
* @dev Return the entire set in an array
*
* WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
* to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
* this function has an unbounded cost, and using it as part of a state-changing function may render the function
* uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
*/
function values(${name} storage set) internal view returns (${type}[] memory) {
bytes32[] memory store = _values(set._inner);
${type}[] memory result;
/// @solidity memory-safe-assembly
assembly {
result := store
}
return result;
}
`;
module.exports = format(
header.trimEnd(),
'library EnumerableSet {',
[defaultSet(), TYPES.map(details => customSet(details).trimEnd()).join('\n\n')],
'}',
);