TinyWebServer - Learning note

connect

ssh -i "/Users/camlostshi/Documents/Codility/project/AWS_EC2_key/SUMMER2023.pem" ubuntu@ec2-18-162-50-109.ap-east-1.compute.amazonaws.com

ssh -i "SUMMER2023.pem" ubuntu@ec2-18-162-50-109.ap-east-1.compute.amazonaws.com

ssh -i "/Users/camlostshi/Documents/Codility/project/AWS_EC2_key/SUMMER2023.pem" ubuntu@ec2-18-166-213-51.ap-east-1.compute.amazonaws.com

mysql

ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY '627221';
FLUSH PRIVILEGES;

mysql -u root -p
627221

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As I meet great difficulty in eating the project's code, I think typing while learning might help me a lot.

My target is to clear explain the principle of the project to others and be able to build the project from zero by myself.

I have no idea about the structure of the note. Let me try to scan the code in the most silly way.

1 About B/S model

Browser/Server model is a special and specific model of C/S (Client/Server) model.

Three layers: Browser, logic server, database system

2 ./lock

It seems operating semaphores. The sem class wrapped thread synchronization mechanism.

int sem_init(sem_t *sem, int pshared, unsigned int value);

Initialize a semaphore with pointer, its type and initial value.

int sem_destroy(sem_t *sem);

int sem_wait(sem_t *sem); // minus 1 or block
int sem_post(sem_t *sem); // add 1 and awake

Mutex locker

int pthread_mutex_init(pthread_mutex_t *restrict mutex, const pthread_mutexattr_t *restrict attr);

int pthread_mutex_lock(pthread_mutex_t *mutex); // call for resource, if locked, block
int pthread_mutex_unlock(pthread_mutex_t *mutex); // release resource

Condition variable

int pthread_cond_init(pthread_cond_t *cv, const pthread_condattr_t *cattr); 
int pthread_cond_wait(pthread_cond_t *cv, pthread_mutex_t *mutex);// call for a cond, protected by a mutex
int pthread_cond_signal(pthread_cond_t *cv); // release a thread
int pthread_cond_timedwait(pthread_cond_t *cv, pthread_mutex_t *mp, const structtimespec * abstime);
int pthread_cond_broadcast(pthread_cond_t *cv); // release all thread

信号量、互斥量、条件变量异同？

实现它们的具体系统调用也不同。

3 ./sqlConnectionPool

Using "mysql/mysql.h": a third-party library from MySQL.

Use sem, lock, cond to protect the procedure of getting and releasing connection.

Wrap contructor in static public function and set it as private function, realized Singleton Pattern.

Initialize once with init() explicitly.

4 ./threadpool

int pthread_create(pthread_t *thread,const pthread_attr_t *attr,void *(*start_routine) (void *),void *arg);
int pthread_join(pthread_t tid, void ** pthread_return);// wait and withdraw
int pthread_detach(pthread_t tid);// don't wait but release at endding

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5 ./timer

6 ./httpConn