forked from safe-global/safe-smart-account
/
OwnerManager.sol
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/
OwnerManager.sol
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// SPDX-License-Identifier: LGPL-3.0-only
pragma solidity >=0.7.0 <0.9.0;
import "../common/SelfAuthorized.sol";
/// @title OwnerManager - Manages a set of owners and a threshold to perform actions.
/// @author Stefan George - <stefan@gnosis.pm>
/// @author Richard Meissner - <richard@gnosis.pm>
contract OwnerManager is SelfAuthorized {
event AddedOwner(address owner);
event RemovedOwner(address owner);
event ChangedThreshold(uint256 threshold);
address internal constant SENTINEL_OWNERS = address(0x1);
mapping(address => address) internal owners;
uint256 internal ownerCount;
uint256 internal threshold;
/// @dev Setup function sets initial storage of contract.
/// @param _owners List of Safe owners.
/// @param _threshold Number of required confirmations for a Safe transaction.
function setupOwners(address[] memory _owners, uint256 _threshold) internal {
// Threshold can only be 0 at initialization.
// Check ensures that setup function can only be called once.
require(threshold == 0, "GS200");
// Validate that threshold is smaller than number of added owners.
require(_threshold <= _owners.length, "GS201");
// There has to be at least one Safe owner.
require(_threshold >= 1, "GS202");
// Initializing Safe owners.
address currentOwner = SENTINEL_OWNERS;
for (uint256 i = 0; i < _owners.length; i++) {
// Owner address cannot be null.
address owner = _owners[i];
require(owner != address(0) && owner != SENTINEL_OWNERS && owner != address(this) && currentOwner != owner, "GS203");
// No duplicate owners allowed.
require(owners[owner] == address(0), "GS204");
owners[currentOwner] = owner;
currentOwner = owner;
}
owners[currentOwner] = SENTINEL_OWNERS;
ownerCount = _owners.length;
threshold = _threshold;
}
/// @dev Allows to add a new owner to the Safe and update the threshold at the same time.
/// This can only be done via a Safe transaction.
/// @notice Adds the owner `owner` to the Safe and updates the threshold to `_threshold`.
/// @param owner New owner address.
/// @param _threshold New threshold.
function addOwnerWithThreshold(address owner, uint256 _threshold) public authorized {
// Owner address cannot be null, the sentinel or the Safe itself.
require(owner != address(0) && owner != SENTINEL_OWNERS && owner != address(this), "GS203");
// No duplicate owners allowed.
require(owners[owner] == address(0), "GS204");
owners[owner] = owners[SENTINEL_OWNERS];
owners[SENTINEL_OWNERS] = owner;
ownerCount++;
emit AddedOwner(owner);
// Change threshold if threshold was changed.
if (threshold != _threshold) changeThreshold(_threshold);
}
/// @dev Allows to remove an owner from the Safe and update the threshold at the same time.
/// This can only be done via a Safe transaction.
/// @notice Removes the owner `owner` from the Safe and updates the threshold to `_threshold`.
/// @param prevOwner Owner that pointed to the owner to be removed in the linked list
/// @param owner Owner address to be removed.
/// @param _threshold New threshold.
function removeOwner(
address prevOwner,
address owner,
uint256 _threshold
) public authorized {
// Only allow to remove an owner, if threshold can still be reached.
require(ownerCount - 1 >= _threshold, "GS201");
// Validate owner address and check that it corresponds to owner index.
require(owner != address(0) && owner != SENTINEL_OWNERS, "GS203");
require(owners[prevOwner] == owner, "GS205");
owners[prevOwner] = owners[owner];
owners[owner] = address(0);
ownerCount--;
emit RemovedOwner(owner);
// Change threshold if threshold was changed.
if (threshold != _threshold) changeThreshold(_threshold);
}
/// @dev Allows to swap/replace an owner from the Safe with another address.
/// This can only be done via a Safe transaction.
/// @notice Replaces the owner `oldOwner` in the Safe with `newOwner`.
/// @param prevOwner Owner that pointed to the owner to be replaced in the linked list
/// @param oldOwner Owner address to be replaced.
/// @param newOwner New owner address.
function swapOwner(
address prevOwner,
address oldOwner,
address newOwner
) public authorized {
// Owner address cannot be null, the sentinel or the Safe itself.
require(newOwner != address(0) && newOwner != SENTINEL_OWNERS && newOwner != address(this), "GS203");
// No duplicate owners allowed.
require(owners[newOwner] == address(0), "GS204");
// Validate oldOwner address and check that it corresponds to owner index.
require(oldOwner != address(0) && oldOwner != SENTINEL_OWNERS, "GS203");
require(owners[prevOwner] == oldOwner, "GS205");
owners[newOwner] = owners[oldOwner];
owners[prevOwner] = newOwner;
owners[oldOwner] = address(0);
emit RemovedOwner(oldOwner);
emit AddedOwner(newOwner);
}
/// @dev Allows to update the number of required confirmations by Safe owners.
/// This can only be done via a Safe transaction.
/// @notice Changes the threshold of the Safe to `_threshold`.
/// @param _threshold New threshold.
function changeThreshold(uint256 _threshold) public authorized {
// Validate that threshold is smaller than number of owners.
require(_threshold <= ownerCount, "GS201");
// There has to be at least one Safe owner.
require(_threshold >= 1, "GS202");
threshold = _threshold;
emit ChangedThreshold(threshold);
}
function getThreshold() public view returns (uint256) {
return threshold;
}
function isOwner(address owner) public view returns (bool) {
return owner != SENTINEL_OWNERS && owners[owner] != address(0);
}
/// @dev Returns array of owners.
/// @return Array of Safe owners.
function getOwners() public view returns (address[] memory) {
address[] memory array = new address[](ownerCount);
// populate return array
uint256 index = 0;
address currentOwner = owners[SENTINEL_OWNERS];
while (currentOwner != SENTINEL_OWNERS) {
array[index] = currentOwner;
currentOwner = owners[currentOwner];
index++;
}
return array;
}
}