class Connection
{
public:
	// 初始化數(shù)據(jù)庫(kù)連接
	Connection();
	// 釋放數(shù)據(jù)庫(kù)連接資源
	~Connection();
	// 連接數(shù)據(jù)庫(kù)
	bool connect(string ip,
		unsigned short port,
		string user,
		string password,
		string dbname);
	// 更新操作 insert、delete、update
	bool update(string sql);
	// 查詢操作 select
	MYSQL_RES* query(string sql);
	// 刷新一下連接的起始的空閑時(shí)間點(diǎn)
	void refreshAliveTime() { _alivetime = clock(); }
	// 返回存活的時(shí)間
	clock_t getAliveeTime()const { return clock() - _alivetime; }
private:
	MYSQL* _conn; // 表示和MySQL Server的一條連接
	clock_t _alivetime; // 記錄進(jìn)入空閑狀態(tài)后的起始存活時(shí)間
};

Connection::Connection()
{
	// 初始化數(shù)據(jù)庫(kù)連接
	_conn = mysql_init(nullptr);
}

Connection::~Connection()
{
	// 釋放數(shù)據(jù)庫(kù)連接資源
	if (_conn != nullptr)
		mysql_close(_conn);
}

bool Connection::connect(string ip, unsigned short port,
	string username, string password, string dbname)
{
	// 連接數(shù)據(jù)庫(kù)
	MYSQL* p = mysql_real_connect(_conn, ip.c_str(), username.c_str(),
		password.c_str(), dbname.c_str(), port, nullptr, 0);
	return p != nullptr;
}

bool Connection::update(string sql)
{
	// 更新操作 insert、delete、update
	if (mysql_query(_conn, sql.c_str()))
	{
		LOG("更新失敗:" + sql);
		return false;
	}
	return true;
}

MYSQL_RES* Connection::query(string sql)
{
	// 查詢操作 select
	if (mysql_query(_conn, sql.c_str()))
	{
		LOG("查詢失敗:" + sql);
		return nullptr;
	}
	return mysql_use_result(_conn);
}

class ConnectionPool
{
public:
	// 獲取連接池對(duì)象實(shí)例
	static ConnectionPool* getConnectionPool();
	// 給外部提供接口，從連接池中獲取一個(gè)可用的空閑連接
	shared_ptr<Connection> getConnection();
private:
	// 單例#1 構(gòu)造函數(shù)私有化
	ConnectionPool();
};

// 線程安全的懶漢單例函數(shù)接口
ConnectionPool* ConnectionPool::getConnectionPool()
{
	static ConnectionPool pool; //靜態(tài)對(duì)象初始化由編譯器自動(dòng)進(jìn)行l(wèi)ock和unlock
	return &pool;
}

// 連接池的構(gòu)造
ConnectionPool::ConnectionPool()
{
	// 加載配置項(xiàng)了
	if (!loadConfigFile())
	{
		return;
	}

	// 創(chuàng)建初始數(shù)量的連接
	for (int i = 0; i < _initSize; ++i)
	{
		Connection* p = new Connection();//創(chuàng)建一個(gè)新的連接
		p->connect(_ip, _port, _username, _password, _dbname);
		p->refreshAliveTime(); // 刷新一下開(kāi)始空閑的起始時(shí)間
		_connectionQue.push(p);
		_connectionCnt++;
	}
}

if (_connectionCnt < _maxSize)
{
	Connection* p = new Connection();
	p->connect(_ip, _port, _username, _password, _dbname);
	p->refreshAliveTime(); // 刷新一下開(kāi)始空閑的起始時(shí)間
	_connectionQue.push(p);
	_connectionCnt++;
}

unique_lock<mutex> lock(_queueMutex);
while (_connectionCnt > _initSize)
{
	Connection* p = _connectionQue.front();
	if (p->getAliveTime() >= (_maxIdleTime * 1000))
	{
		_connectionQue.pop();
		_connectionCnt--;
		// 調(diào)用~Connection()釋放連接
		delete p;
	}
	else
	{
		// 如果隊(duì)頭的連接沒(méi)有超過(guò)_maxIdleTime，其他連接肯定沒(méi)有
		break;
	}
}

int main()
{
	thread t1([]() {
		for (int i = 0; i < 250; ++i)
		{
			Connection conn;
			char sql[1024] = { 0 };
			sprintf(sql, "insert into user(name,age,sex) values('%s',%d,'%s')",
				"zhang san", 20, "M");
			conn.connect("127.0.0.1", 3306, "root", "991205", "chat");
			conn.update(sql);
		}
		});
	thread t2([]() {
		for (int i = 0; i < 250; ++i)
		{
			Connection conn;
			char sql[1024] = { 0 };
			sprintf(sql, "insert into user(name,age,sex) values('%s',%d,'%s')",
				"zhang san", 20, "M");
			conn.connect("127.0.0.1", 3306, "root", "991205", "chat");
			conn.update(sql);
		}
		});
	thread t3([]() {
		for (int i = 0; i < 250; ++i)
		{
			Connection conn;
			char sql[1024] = { 0 };
			sprintf(sql, "insert into user(name,age,sex) values('%s',%d,'%s')",
				"zhang san", 20, "M");
			conn.connect("127.0.0.1", 3306, "root", "991205", "chat");
			conn.update(sql);
		}
		});
	thread t4([]() {
		for (int i = 0; i < 250; ++i)
		{
			Connection conn;
			char sql[1024] = { 0 };
			sprintf(sql, "insert into user(name,age,sex) values('%s',%d,'%s')",
				"zhang san", 20, "male");
			conn.connect("127.0.0.1", 3306, "root", "991205", "chat");
			conn.update(sql);
		}
		});

	t1.join();
	t2.join();
	t3.join();
	t4.join();

	return 0;
}

class ConnectionPool
{
private:
	// 設(shè)置條件變量，用于連接生產(chǎn)線程和連接消費(fèi)線程的通信
	condition_variable cv;				
	// 維護(hù)連接隊(duì)列的線程安全互斥鎖
	mutex _queueMutex;
};

for (;;)
{
	unique_lock<mutex> lock(_queueMutex);
	while (!_connectionQue.empty())
	{
		// 隊(duì)列不為空，此處生產(chǎn)線程進(jìn)入等待狀態(tài)
		cv.wait(lock);
	}

	// 連接數(shù)量沒(méi)有達(dá)到上限，繼續(xù)創(chuàng)建新的連接
	if (_connectionCnt < _maxSize)
	{
		Connection* p = new Connection();
		p->connect(_ip, _port, _username, _password, _dbname);
		// 刷新一下開(kāi)始空閑的起始時(shí)間
		p->refreshAliveTime();
		_connectionQue.push(p);
		_connectionCnt++;
	}

	// 通知消費(fèi)者線程,可以消費(fèi)連接了
	cv.notify_all();
}

// 啟動(dòng)一個(gè)新的線程，作為連接的生產(chǎn)者 linux thread => pthread_create
thread produce(std::bind(&ConnectionPool::produceConnectionTask, this));
produce.detach();

// 啟動(dòng)一個(gè)新的定時(shí)線程，掃描超過(guò)maxIdleTime時(shí)間的空閑連接，進(jìn)行對(duì)于的連接回收
thread scanner(std::bind(&ConnectionPool::scannerConnectionTask, this));
scanner.detach();

atomic_int _connectionCnt; // 記錄連接所創(chuàng)建的connection連接的總數(shù)量 

// 生產(chǎn)新連接時(shí)：
_connectionCnt++;
// 當(dāng)新連接超過(guò)最大超時(shí)時(shí)間后被銷(xiāo)毀時(shí)
_connectionCnt--;

shared_ptr<Connection> sp(_connectionQue.front(),
	[&](Connection* pcon) {
		// 這里是在服務(wù)器應(yīng)用線程中調(diào)用的，所以一定要考慮隊(duì)列的線程安全操作
		unique_lock<mutex> lock(_queueMutex);
		pcon->refreshAliveTime();
		_connectionQue.push(pcon);
	});

int main()
{
	clock_t begin = clock();
	for (int i = 0; i < 1000; ++i)
	{
		Connection conn;
		char sql[1024] = { 0 };
		sprintf(sql, "insert into user(name,age,sex) values('%s',%d,'%s')",
			"zhang san", 20, "M");
		conn.connect("127.0.0.1", 3306, "root", "123456", "chat");
		conn.update(sql);
	}
	clock_t end = clock();
	cout << (end - begin) << "ms" << endl;
	return 0;
}

int main()
{
	Connection conn;
	conn.connect("127.0.0.1", 3306, "root", "991205", "chat");
	clock_t begin = clock();

	thread t1([]() {
		for (int i = 0; i < 250; ++i)
		{
			Connection conn;
			char sql[1024] = { 0 };
			sprintf(sql, "insert into user(name,age,sex) values('%s',%d,'%s')",
				"zhang san", 20, "M");
			conn.connect("127.0.0.1", 3306, "root", "123456", "chat");
			conn.update(sql);
		}
		});
	thread t2([]() {
		for (int i = 0; i < 250; ++i)
		{
			Connection conn;
			char sql[1024] = { 0 };
			sprintf(sql, "insert into user(name,age,sex) values('%s',%d,'%s')",
				"zhang san", 20, "M");
			conn.connect("127.0.0.1", 3306, "root", "123456", "chat");
			conn.update(sql);
		}
		});
	thread t3([]() {
		for (int i = 0; i < 250; ++i)
		{
			Connection conn;
			char sql[1024] = { 0 };
			sprintf(sql, "insert into user(name,age,sex) values('%s',%d,'%s')",
				"zhang san", 20, "M");
			conn.connect("127.0.0.1", 3306, "root", "123456", "chat");
			conn.update(sql);
		}
});
	thread t4([]() {
		for (int i = 0; i < 250; ++i)
		{
			Connection conn;
			char sql[1024] = { 0 };
			sprintf(sql, "insert into user(name,age,sex) values('%s',%d,'%s')",
				"zhang san", 20, "M");
			conn.connect("127.0.0.1", 3306, "root", "123456", "chat");
			conn.update(sql);
		}
		});

	t1.join();
	t2.join();
	t3.join();
	t4.join();

	clock_t end = clock();
	cout << (end - begin) << "ms" << endl;
	return 0;
}

int main()
{
	clock_t begin = clock();
	ConnectionPool* cp = ConnectionPool::getConnectionPool();
	for (int i = 0; i < 1000; ++i)
	{
		shared_ptr<Connection> sp = cp->getConnection();
		char sql[1024] = { 0 };
		sprintf(sql, "insert into user(name,age,sex) values('%s',%d,'%s')",
			"zhang san", 20, "M");
		sp->update(sql);
	}

	clock_t end = clock();
	cout << (end - begin) << "ms" << endl;
	return 0;
}

int main()
{
	clock_t begin = clock();

	thread t1([]() {
		ConnectionPool* cp = ConnectionPool::getConnectionPool();
		for (int i = 0; i < 250; ++i)
		{
			char sql[1024] = { 0 };
			sprintf(sql, "insert into user(name,age,sex) values('%s',%d,'%s')",
				"zhang san", 20, "M");
			shared_ptr<Connection> sp = cp->getConnection();
			sp->update(sql);
		}
		});
	thread t2([]() {
		ConnectionPool* cp = ConnectionPool::getConnectionPool();
		for (int i = 0; i < 250; ++i)
		{
			char sql[1024] = { 0 };
			sprintf(sql, "insert into user(name,age,sex) values('%s',%d,'%s')",
				"zhang san", 20, "M");
			shared_ptr<Connection> sp = cp->getConnection();
			sp->update(sql);
		}
		});
	thread t3([]() {
		ConnectionPool* cp = ConnectionPool::getConnectionPool();
		for (int i = 0; i < 250; ++i)
		{
			char sql[1024] = { 0 };
			sprintf(sql, "insert into user(name,age,sex) values('%s',%d,'%s')",
				"zhang san", 20, "M");
			shared_ptr<Connection> sp = cp->getConnection();
			sp->update(sql);
		}
		});
	thread t4([]() {
		ConnectionPool* cp = ConnectionPool::getConnectionPool();
		for (int i = 0; i < 250; ++i)
		{
			char sql[1024] = { 0 };
			sprintf(sql, "insert into user(name,age,sex) values('%s',%d,'%s')",
				"zhang san", 20, "M");
			shared_ptr<Connection> sp = cp->getConnection();
			sp->update(sql);
		}
		});

	t1.join();
	t2.join();
	t3.join();
	t4.join();

	clock_t end = clock();
	cout << (end - begin) << "ms" << endl;
	return 0;
		}