store boolean instead of address (#493)

* store boolean instead of address

* adjustments

* remove unnecessary constants

* rename locker to caller everywhere

.forge-snapshots/addLiquidity with empty hook.snap

@@ -1 +1 @@
-312661
+312292

.forge-snapshots/addLiquidity with native token.snap

@@ -1 +1 @@
-192843
+192474

.forge-snapshots/addLiquidity.snap

@@ -1 +1 @@
-192821
+192452

.forge-snapshots/before swap hook, already cached dynamic fee.snap

@@ -1 +1 @@
-184735
+184412

.forge-snapshots/cached dynamic fee, no hooks.snap

@@ -1 +1 @@
-138762
+138439

.forge-snapshots/donate gas with 1 token.snap

@@ -1 +1 @@
-131854
+131592

.forge-snapshots/donate gas with 2 tokens.snap

@@ -1 +1 @@
-176958
+176613

.forge-snapshots/erc20 collect protocol fees.snap

@@ -1 +1 @@
-24982
+24960

.forge-snapshots/initialize.snap

@@ -1 +1 @@
-51725
+51767

.forge-snapshots/native collect protocol fees.snap

@@ -1 +1 @@
-36655
+36633

.forge-snapshots/poolManager bytecode size.snap

@@ -1 +1 @@
-23345
+23279

.forge-snapshots/removeLiquidity with empty hook.snap

@@ -1 +1 @@
-99632
+99307

.forge-snapshots/removeLiquidity with native token.snap

@@ -1 +1 @@
-201005
+200680

.forge-snapshots/removeLiquidity.snap

@@ -1 +1 @@
-197282
+196957

.forge-snapshots/simple swap with native.snap

@@ -1 +1 @@
-187335
+187012

.forge-snapshots/simple swap.snap

@@ -1 +1 @@
-195872
+195549

.forge-snapshots/swap against liquidity with native token.snap

@@ -1 +1 @@
-117998
+117675

.forge-snapshots/swap against liquidity.snap

@@ -1 +1 @@
-105462
+105139

.forge-snapshots/swap burn 6909 for input.snap

@@ -1 +1 @@
-125651
+125350

.forge-snapshots/swap burn native 6909 for input.snap

@@ -1 +1 @@
-121604
+121303

.forge-snapshots/swap mint native output as 6909.snap

@@ -1 +1 @@
-189861
+189538

.forge-snapshots/swap mint output as 6909.snap

@@ -1 +1 @@
-206666
+206343

.forge-snapshots/swap with dynamic fee.snap

@@ -1 +1 @@
-183836
+183513

.forge-snapshots/swap with hooks.snap

@@ -1 +1 @@
-105440
+105117

.forge-snapshots/update dynamic fee in before swap.snap

@@ -1 +1 @@
-190540
+190217

src/PoolManager.sol

@@ -19,7 +19,7 @@ import {Fees} from "./Fees.sol";
 import {ERC6909Claims} from "./ERC6909Claims.sol";
 import {PoolId, PoolIdLibrary} from "./types/PoolId.sol";
 import {BalanceDelta, BalanceDeltaLibrary} from "./types/BalanceDelta.sol";
-import {Locker} from "./libraries/Locker.sol";
+import {Lock} from "./libraries/Lock.sol";
 import {NonZeroDeltaCount} from "./libraries/NonZeroDeltaCount.sol";
 import {PoolGetters} from "./libraries/PoolGetters.sol";
 
@@ -40,10 +40,10 @@ contract PoolManager is IPoolManager, Fees, NoDelegateCall, ERC6909Claims {
     /// @inheritdoc IPoolManager
     int24 public constant MIN_TICK_SPACING = TickMath.MIN_TICK_SPACING;
 
-    /// @dev Represents the currencies due/owed to each locker.
-    /// Must all net to zero when the last lock is released.
+    /// @dev Represents the currencies due/owed to each caller.
+    /// Must all net to zero when the lock is released.
     /// TODO this needs to be transient
-    mapping(address locker => mapping(Currency currency => int256 currencyDelta)) public currencyDelta;
+    mapping(address caller => mapping(Currency currency => int256 currencyDelta)) public currencyDelta;
 
     /// @inheritdoc IPoolManager
     mapping(Currency currency => uint256) public override reservesOf;
@@ -88,14 +88,13 @@ contract PoolManager is IPoolManager, Fees, NoDelegateCall, ERC6909Claims {
         return pools[id].positions.get(_owner, tickLower, tickUpper);
     }
 
-    /// @inheritdoc IPoolManager
-    function getLocker() external view override returns (address locker) {
-        return Locker.getLocker();
+    function isLockSet() external view returns (bool) {
+        return Lock.isLocked();
     }
 
-    /// @notice This will revert if a function is called by any address other than the current locker OR the most recently called, pre-permissioned hook.
+    /// @notice This will revert if the contract is not locked
     modifier isLocked() {
-        if (!Locker.isLocked()) revert ManagerNotLocked();
+        if (!Lock.isLocked()) revert ManagerNotLocked();
         _;
     }
 
@@ -129,15 +128,15 @@ contract PoolManager is IPoolManager, Fees, NoDelegateCall, ERC6909Claims {
 
     /// @inheritdoc IPoolManager
     function lock(bytes calldata data) external payable override returns (bytes memory result) {
-        if (Locker.isLocked()) revert AlreadyLocked();
+        if (Lock.isLocked()) revert AlreadyLocked();
 
-        Locker.setLocker(msg.sender);
+        Lock.lock();
 
         // the caller does everything in this callback, including paying what they owe via calls to settle
         result = ILockCallback(msg.sender).lockAcquired(data);
 
         if (NonZeroDeltaCount.read() != 0) revert CurrencyNotSettled();
-        Locker.clearLocker();
+        Lock.unlock();
     }
 
     function _accountDelta(Currency currency, int128 delta) internal {

src/interfaces/IHooks.sol

@@ -106,7 +106,7 @@ interface IHooks {
     /// @param sender The initial msg.sender for the swap call
     /// @param key The key for the pool
     /// @param params The parameters for the swap
-    /// @param delta The amount owed to the locker (positive) or owed to the pool (negative)
+    /// @param delta The amount owed to the caller (positive) or owed to the pool (negative)
     /// @param hookData Arbitrary data handed into the PoolManager by the swapper to be be passed on to the hook
     /// @return bytes4 The function selector for the hook
     function afterSwap(

src/interfaces/IPoolManager.sol

@@ -120,8 +120,8 @@ interface IPoolManager is IFees, IERC6909Claims {
     /// @notice Returns the reserves for a given ERC20 currency
     function reservesOf(Currency currency) external view returns (uint256);
 
-    /// @notice Returns the locker of the pool
-    function getLocker() external view returns (address locker);
+    /// @notice Returns whether the contract is locked
+    function isLockSet() external view returns (bool);
 
     /// @notice Returns the number of nonzero deltas open on the PoolManager that must be zerod by the close of the initial lock.
     function getLockNonzeroDeltaCount() external view returns (uint256 _nonzeroDeltaCount);
@@ -131,10 +131,10 @@ interface IPoolManager is IFees, IERC6909Claims {
         external
         returns (int24 tick);
 
-    /// @notice Get the current delta for a locker in the given currency
-    /// @param locker The address of the locker
+    /// @notice Get the current delta for a caller in the given currency
+    /// @param caller The address of the caller
     /// @param currency The currency for which to lookup the delta
-    function currencyDelta(address locker, Currency currency) external view returns (int256);
+    function currencyDelta(address caller, Currency currency) external view returns (int256);
 
     /// @notice All operations go through this function
     /// @param data Any data to pass to the callback, via `ILockCallback(msg.sender).lockAcquired(data)`

src/libraries/Hooks.sol

@@ -6,7 +6,6 @@ import {IHooks} from "../interfaces/IHooks.sol";
 import {FeeLibrary} from "./FeeLibrary.sol";
 import {BalanceDelta} from "../types/BalanceDelta.sol";
 import {IPoolManager} from "../interfaces/IPoolManager.sol";
-import {Locker} from "./Locker.sol";
 
 /// @notice V4 decides whether to invoke specific hooks by inspecting the leading bits of the address that
 /// the hooks contract is deployed to.

src/libraries/Lock.sol

@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: BUSL-1.1
+pragma solidity ^0.8.20;
+
+import {IHooks} from "../interfaces/IHooks.sol";
+
+/// @notice This is a temporary library that allows us to use transient storage (tstore/tload)
+/// TODO: This library can be deleted when we have the transient keyword support in solidity.
+library Lock {
+    // The slot holding the lock, transiently
+    uint256 constant LOCK_SLOT = uint256(keccak256("Lock")) - 1;
+
+    function lock() internal {
+        uint256 slot = LOCK_SLOT;
+        assembly {
+            // set the lock
+            tstore(slot, true)
+        }
+    }
+
+    function unlock() internal {
+        uint256 slot = LOCK_SLOT;
+        assembly {
+            tstore(slot, false)
+        }
+    }
+
+    function isLocked() internal view returns (bool locked) {
+        uint256 slot = LOCK_SLOT;
+        assembly {
+            locked := tload(slot)
+        }
+    }
+}