智能合約是在區(qū)塊鏈上運(yùn)行的計算機(jī)程序。程序包括函數(shù)和數(shù)據(jù)（也稱為變量或參數(shù)），這些函數(shù)操作數(shù)據(jù)。函數(shù)使用的數(shù)據(jù)需要存儲在計算機(jī)的內(nèi)存中。在這種情況下，計算機(jī)是EVM。

　　存儲內(nèi)存類型的概念是區(qū)塊鏈所特有的，因?yàn)樵谥悄芎霞s中工作時，通過區(qū)塊鏈的加密封存屬性，存儲的數(shù)據(jù)是無法篡改的。在其他編程環(huán)境中，如果我們想要長期存儲變量，通常會將這項工作轉(zhuǎn)移到文件系統(tǒng)或數(shù)據(jù)庫中。但在區(qū)塊鏈上，智能合約的代碼和數(shù)據(jù)都長期保留在區(qū)塊鏈上。

　　//SPDX-License-Identifier:BUSL-1.1

　　pragma solidity=0.7.6;

　　import'./interfaces/IUniswapV3Factory.sol';

　　import'./UniswapV3PoolDeployer.sol';

　　import'./NoDelegateCall.sol';

　　import'./UniswapV3Pool.sol';

　　///title Canonical Uniswap V3 factory

　　///notice Deploys Uniswap V3 pools and manages ownership and control over pool protocol fees

　　contract UniswapV3Factory is IUniswapV3Factory,UniswapV3PoolDeployer,NoDelegateCall{

　　///inheritdoc IUniswapV3Factory

　　address public override owner;

　　///inheritdoc IUniswapV3Factory

　　mapping(uint24=>int24)public override feeAmountTickSpacing;

　　///inheritdoc IUniswapV3Factory

　　mapping(address=>mapping(address=>mapping(uint24=>address)))public override getPool;

　　constructor(){

　　owner=msg.sender;

　　emit OwnerChanged(address(0),msg.sender);

　　feeAmountTickSpacing[500]=10;

　　emit FeeAmountEnabled(500,10);

　　feeAmountTickSpacing[3000]=60;

　　emit FeeAmountEnabled(3000,60);

　　feeAmountTickSpacing[10000]=200;

　　emit FeeAmountEnabled(10000,200);

　　}

　　///inheritdoc IUniswapV3Factory

　　function createPool(

　　address tokenA,

　　address tokenB,

　　uint24 fee

　　)external override noDelegateCall returns(address pool){

　　require(tokenA!=tokenB);

　　(address token0,address token1)=tokenA<tokenB?(tokenA,tokenB):(tokenB,tokenA);

　　require(token0!=address(0));

　　int24 tickSpacing=feeAmountTickSpacing[fee];

　　require(tickSpacing!=0);

　　require(getPool[token0][token1][fee]==address(0));

　　pool=deploy(address(this),token0,token1,fee,tickSpacing);

　　getPool[token0][token1][fee]=pool;

　　//populate mapping in the reverse direction,deliberate choice to avoid the cost of comparing addresses

　　getPool[token1][token0][fee]=pool;

　　emit PoolCreated(token0,token1,fee,tickSpacing,pool);

　　}

　　///inheritdoc IUniswapV3Factory

　　function setOwner(address _owner)external override{

　　require(msg.sender==owner);

　　emit OwnerChanged(owner,_owner);

　　owner=_owner;

　　}

　　///inheritdoc IUniswapV3Factory

　　function enableFeeAmount(uint24 fee,int24 tickSpacing)public override{

　　require(msg.sender==owner);

　　require(fee<1000000);

　　//tick spacing is capped at 16384 to prevent the situation where tickSpacing is so large that

　　//TickBitmap#nextInitializedTickWithinOneWord overflows int24 container from a valid tick

　　//16384 ticks represents a>5x price change with ticks of 1 bips

　　require(tickSpacing>0&&tickSpacing<16384);

　　require(feeAmountTickSpacing[fee]==0);

　　feeAmountTickSpacing[fee]=tickSpacing;

　　emit FeeAmountEnabled(fee,tickSpacing);

　　}

　　}