feat: add a fetcher util contract for sqrtpricex96

.gitmodules

@@ -10,3 +10,9 @@
 [submodule "contracts/utils/lib/solmate"]
 	path = contracts/utils/lib/solmate
 	url = https://github.com/transmissions11/solmate
+[submodule "lib/v4-core"]
+	path = lib/v4-core
+	url = https://github.com/uniswap/v4-core
+[submodule "contracts/utils/lib/v4-core"]
+	path = contracts/utils/lib/v4-core
+	url = https://github.com/uniswap/v4-core

contracts/utils/src/Fetcher.sol

@@ -0,0 +1,40 @@
+pragma solidity ^0.8.10;
+
+import {PoolId} from "v4-core/types/PoolId.sol";
+import {IPoolManager} from "v4-core/interfaces/IPoolManager.sol";
+import {Position} from "v4-core/libraries/Position.sol";
+
+// This contract is a compact version of StateLibrary, which can be found below.
+// https://github.com/Uniswap/v4-core/blob/799dd2cb980319a8d3b827b6a7aa59a606634553/src/libraries/StateLibrary.sol
+contract Fetcher {
+    bytes32 public constant POOLS_SLOT = bytes32(uint256(6));
+
+    function _getPoolStateSlot(PoolId poolId) internal pure returns (bytes32) {
+        return keccak256(abi.encodePacked(PoolId.unwrap(poolId), POOLS_SLOT));
+    }
+
+    function getSlot0(IPoolManager manager, PoolId poolId)
+        external
+        view
+        returns (uint160 sqrtPriceX96, int24 tick, uint24 protocolFee, uint24 lpFee)
+    {
+        // slot key of Pool.State value: `pools[poolId]`
+        bytes32 stateSlot = _getPoolStateSlot(poolId);
+
+        bytes32 data = manager.extsload(stateSlot);
+
+        //   24 bits  |24bits|24bits      |24 bits|160 bits
+        // 0x000000   |000bb8|000000      |ffff75 |0000000000000000fe3aa841ba359daa0ea9eff7
+        // ---------- | fee  |protocolfee | tick  | sqrtPriceX96
+        assembly ("memory-safe") {
+            // bottom 160 bits of data
+            sqrtPriceX96 := and(data, 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF)
+            // next 24 bits of data
+            tick := signextend(2, shr(160, data))
+            // next 24 bits of data
+            protocolFee := and(shr(184, data), 0xFFFFFF)
+            // last 24 bits of data
+            lpFee := and(shr(208, data), 0xFFFFFF)
+        }
+    }
+}