Liquity

1/ SPDX-License-Identifier: MIT
2
3pragma solidity 0.6.11;
4
5import './Interfaces/IActivePool.sol';
6import "./Dependencies/SafeMath.sol";
7import "./Dependencies/Ownable.sol";
8import "./Dependencies/CheckContract.sol";
9import "./Dependencies/console.sol";
10
11/*
12 * The Active Pool holds the ETH collateral and LUSD debt (but not LUSD tokens) for all active troves.
13 *
14 * When a trove is liquidated, it's ETH and LUSD debt are transferred from the Active Pool, to either the
15 * Stability Pool, the Default Pool, or both, depending on the liquidation conditions.
16 *
17 */
18contract ActivePool is Ownable, CheckContract, IActivePool {
19    using SafeMath for uint256;
20
21    string constant public NAME = "ActivePool";
22
23    address public borrowerOperationsAddress;
24    address public troveManagerAddress;
25    address public stabilityPoolAddress;
26    address public defaultPoolAddress;
27    uint256 internal ETH;  // deposited ether tracker
28    uint256 internal LUSDDebt;
29
30    // --- Events ---
31
32    event BorrowerOperationsAddressChanged(address _newBorrowerOperationsAddress);
33    event TroveManagerAddressChanged(address _newTroveManagerAddress);
34    event ActivePoolLUSDDebtUpdated(uint _LUSDDebt);
35    event ActivePoolETHBalanceUpdated(uint _ETH);
36
37    // --- Contract setters ---
38
39    function setAddresses(
40        address _borrowerOperationsAddress,
41        address _troveManagerAddress,
42        address _stabilityPoolAddress,
43        address _defaultPoolAddress
44    )
45        external
46        onlyOwner
47    {
48        checkContract(_borrowerOperationsAddress);
49        checkContract(_troveManagerAddress);
50        checkContract(_stabilityPoolAddress);
51        checkContract(_defaultPoolAddress);
52
53        borrowerOperationsAddress = _borrowerOperationsAddress;
54        troveManagerAddress = _troveManagerAddress;
55        stabilityPoolAddress = _stabilityPoolAddress;
56        defaultPoolAddress = _defaultPoolAddress;
57
58        emit BorrowerOperationsAddressChanged(_borrowerOperationsAddress);
59        emit TroveManagerAddressChanged(_troveManagerAddress);
60        emit StabilityPoolAddressChanged(_stabilityPoolAddress);
61        emit DefaultPoolAddressChanged(_defaultPoolAddress);
62
63        _renounceOwnership();
64    }
65
66    // --- Getters for public variables. Required by IPool interface ---
67
68    /*
69    * Returns the ETH state variable.
70    *
71    *Not necessarily equal to the the contract's raw ETH balance - ether can be forcibly sent to contracts.
72    */
73    function getETH() external view override returns (uint) {
74        return ETH;
75    }
76
77    function getLUSDDebt() external view override returns (uint) {
78        return LUSDDebt;
79    }
80
81    // --- Pool functionality ---
82
83    function sendETH(address _account, uint _amount) external override {
84        _requireCallerIsBOorTroveMorSP();
85        ETH = ETH.sub(_amount);
86        emit ActivePoolETHBalanceUpdated(ETH);
87        emit EtherSent(_account, _amount);
88
89        (bool success, ) = _account.call{ value: _amount }("");
90        require(success, "ActivePool: sending ETH failed");
91    }
92
93    function increaseLUSDDebt(uint _amount) external override {
94        _requireCallerIsBOorTroveM();
95        LUSDDebt  = LUSDDebt.add(_amount);
96        ActivePoolLUSDDebtUpdated(LUSDDebt);
97    }
98
99    function decreaseLUSDDebt(uint _amount) external override {
100        _requireCallerIsBOorTroveMorSP();
101        LUSDDebt = LUSDDebt.sub(_amount);
102        ActivePoolLUSDDebtUpdated(LUSDDebt);
103    }
104
105    // --- 'require' functions ---
106
107    function _requireCallerIsBorrowerOperationsOrDefaultPool() internal view {
108        require(
109            msg.sender == borrowerOperationsAddress ||
110            msg.sender == defaultPoolAddress,
111            "ActivePool: Caller is neither BO nor Default Pool");
112    }
113
114    function _requireCallerIsBOorTroveMorSP() internal view {
115        require(
116            msg.sender == borrowerOperationsAddress ||
117            msg.sender == troveManagerAddress ||
118            msg.sender == stabilityPoolAddress,
119            "ActivePool: Caller is neither BorrowerOperations nor TroveManager nor StabilityPool");
120    }
121
122    function _requireCallerIsBOorTroveM() internal view {
123        require(
124            msg.sender == borrowerOperationsAddress ||
125            msg.sender == troveManagerAddress,
126            "ActivePool: Caller is neither BorrowerOperations nor TroveManager");
127    }
128
129    // --- Fallback function ---
130
131    receive() external payable {
132        _requireCallerIsBorrowerOperationsOrDefaultPool();
133        ETH = ETH.add(msg.value);
134        emit ActivePoolETHBalanceUpdated(ETH);
135    }
136}