AMM Layer | PoolManager

Pool Managers are singleton contract that encapsulates the logic for different types of AMMs. In the initial deployment, there will be 2 AMM types, visit their respective page to learn more about them.

Singleton

In PancakeSwap v3, each pool is a separate contract. In PancakeSwap v4, all pools will be encapsulated in a single PoolManager contract. For example, all concentrated liquidity pools in CLPoolManager and all liquidity book pools in BinPoolManager

PoolKey | PoolId

PoolKey is a struct which describe each pool.

/// @notice Returns the key for identifying a pool
struct PoolKey {
    /// @notice The lower currency of the pool, sorted numerically
    Currency currency0;
    /// @notice The higher currency of the pool, sorted numerically
    Currency currency1;
    /// @notice The hooks of the pool, won't have a general interface because hooks interface vary on pool type
    IHooks hooks;
    /// @notice The pool manager of the pool
    IPoolManager poolManager;
    /// @notice The pool swap fee, capped at 1_000_000. The upper 4 bits determine if the hook sets any fees.
    uint24 fee;
    /// @notice Hooks callback and pool specific parameters, i.e. tickSpacing for CL, binStep for bin
    bytes32 parameters;
}

PoolId is a bytes32 of keccak256(abi.encode(poolKey)) You will notice some input from PoolManager requiring PoolId. Derive PoolId from PoolKey via the following:

import {PoolIdLibrary} from "@pancakeswap/v4-core/src/types/PoolId.sol";
 
// Use PoolIdLibrary for PoolKey type
using PoolIdLibrary for PoolKey;
 
PoolKey memory key = PoolKey({
  currency0: currency0,
  currency1: currency1
  hooks: IHooks(address(0)),
  poolManager: poolManager,
  fee: uint24(3000),
  parameters: bytes32(uint256(counterHook.getHooksRegistrationBitmap())).setTickSpacing(10)
});
 
// Get PoolId from PoolKey via PoolIdLibrary
Poolid id = key.toId();

Initializing a Pool

Before swap or liquidity operations can be performed on a pool, the first step would be to initialize the pool. To initialize, call either CLPoolManager or BinPoolManager initialize method.

// CLPoolManager
function initialize(PoolKey memory key, uint160 sqrtPriceX96, bytes calldata hookData);
 
// BinPoolManager
function initialize(PoolKey memory key, uint24 activeId, bytes calldata hookData);