add poolHeartbeat

contracts/DODOFee/PoolHeartBeat.sol

@@ -0,0 +1,46 @@
+/*
+
+    Copyright 2022 DODO ZOO.
+    SPDX-License-Identifier: Apache-2.0
+
+*/
+
+pragma solidity 0.6.9;
+
+import {InitializableOwnable} from "../lib/InitializableOwnable.sol";
+
+
+contract PoolHeartBeat is InitializableOwnable {
+
+    struct heartBeat {
+        uint256 lastHeartBeat;
+        uint256 maxInterval;
+    }
+    
+    mapping(address => address) public poolHeartBeatManager; // pool => heartbeat manager
+    mapping(address => heartBeat) public beats; // heartbeat manager => heartbeat
+
+    function isPoolHeartBeatLive(address pool) external view returns(bool) {
+        if(poolHeartBeatManager[pool]==address(0)) {
+            return true;
+        }
+        heartBeat memory beat = beats[poolHeartBeatManager[pool]];
+        return block.timestamp - beat.lastHeartBeat < beat.maxInterval;
+    }
+
+    function triggerBeat() external {
+        heartBeat storage beat = beats[msg.sender];
+        beat.lastHeartBeat = block.timestamp;
+    }
+
+    function setBeatInterval(uint256 interval) external {
+        heartBeat storage beat = beats[msg.sender];
+        beat.maxInterval = interval;
+    }
+
+    function bindPoolHeartBeat(address[] memory pools, address manager) external onlyOwner {
+        for(uint256 i=0; i<pools.length; i++) {
+            poolHeartBeatManager[pools[i]] = manager;
+        }
+    }
+}