? POC(?? ??)??? Rust ??? ?? ??? ??? ????? C ?? ???? ????? ??? ?? ?? ??? ????.

Rust ??? ???: C?? ??

??? ???: C?? Rust??? ??? ??

??

1. ??
2. ???
3. C? ??
• 3.1. ?? ?????? ???? ?? ??
  3.2. Mutex? ??
4. ?????? ??
• 4.1. ?? ?? ??
  4.2. Mutex ? Arc? ??? ??
  4.3. ??? ? RwLock
5. ??
6. ????

---

1. ??

?????

???? ????? ??? ??? ??? ? ?? ?? ???? ??? ? ?????. ???? ???? ?? ??? ???? ??? ???? ? ? ??? ? ???, ? ??? ???? ??? ???? ??? ? ?? ?? ??? ?? ??? ?????.

---

2. ???

???? ??? ??? ??? ? ?? ?? ?????. ?? ???? ??? ??? ???? ???? ??? ???? ?? ???? ??? ? ????.

???? ???? ??? ????? ?? ?? ???? ???? ? ??? ?????.

?? ???? ???? ?? ??? ?? ?? CPU ???? ??? ???? ???? ??? ? ????. ?? ?? ????? ?? ??? ????? ? ? ???? ???? ??? ?? ??? ?? ? ????.

---

3. C? ??

C?? ??? ???? ??? ?????.

?? ??? 1000???.
?? ?? ??? ? ? ?? ??? ?????.
???? ???? ??? ????? ?? ?????.

3.1. ?? ?????? ???? ?? ??

int saldo = 1000; 

void creditar(int valor) {
    int tmp_saldo = saldo;

    sleep(1); // Delay simulado

    saldo += tmp_saldo + valor;
}

void debitar(int valor) {
    int temp = saldo;

    sleep(1); // Delay simulado

    if (temp >= valor) {
        saldo = temp - valor;
    }
}

void* processar_transacao(void* arg) {
    int valor = *(int*)arg;

    if (valor > 0) {
        creditar(valor);
    } else {
        debitar(abs(valor));
    }

    return NULL;
}

int main() {
    int transactions[] = {100, -50, 200, -150, 300, -200, 150, -100, 50, -50};
    int num_transactions = sizeof(transactions) / sizeof(transactions[0]);

    pthread_t threads[num_transactions];

    for (int i = 0; i < num_transactions; i++) {
        pthread_create(&threads[i], NULL, processar_transacao, &transactions[i]); // Cria uma thread para cada transa??o
    }

    for (int i = 0; i < num_transactions; i++) {
        pthread_join(threads[i], NULL); // Aguarda todas as threads terminarem
    }

    printf("Saldo final da conta: %d\n", saldo);
    return 0;
}

????? ??? ?? ??? ???? ?? ??? ??? ? ???, 2?? ???? ??? ?? ????? ???? ?? ??? ?????. ? ??? ?? ? ???? ?? ? ????? ????? ?? ???? ???? ?? ??? ?????.

? ??? ?? ? ???? ???? ??? ???? ??? ????? ?? ??? ?????.

---

3.2. Mutex? ??

int saldo = 1000; 

void creditar(int valor) {
    int tmp_saldo = saldo;

    sleep(1); // Delay simulado

    saldo += tmp_saldo + valor;
}

void debitar(int valor) {
    int temp = saldo;

    sleep(1); // Delay simulado

    if (temp >= valor) {
        saldo = temp - valor;
    }
}

void* processar_transacao(void* arg) {
    int valor = *(int*)arg;

    if (valor > 0) {
        creditar(valor);
    } else {
        debitar(abs(valor));
    }

    return NULL;
}

int main() {
    int transactions[] = {100, -50, 200, -150, 300, -200, 150, -100, 50, -50};
    int num_transactions = sizeof(transactions) / sizeof(transactions[0]);

    pthread_t threads[num_transactions];

    for (int i = 0; i < num_transactions; i++) {
        pthread_create(&threads[i], NULL, processar_transacao, &transactions[i]); // Cria uma thread para cada transa??o
    }

    for (int i = 0; i < num_transactions; i++) {
        pthread_join(threads[i], NULL); // Aguarda todas as threads terminarem
    }

    printf("Saldo final da conta: %d\n", saldo);
    return 0;
}

???? ? ?? ??? ???? ?? ???? ???? ? ??? ???? ??? ?? ?????. ????? ??? "?? ??"? ???? ?? ?? ?? ???? ???????.

???? ???? ???? ??? ???? ????? ?? ???? ? ?? ???? ???? ??? ??? ?? ?????. ?? ? ? ??? ????(???)? ?? ???? ??? ????? ?? ?????.

4. ?????? ??

int saldo = 1000; 
pthread_mutex_t saldo_mutex; // Mutex para proteger o saldo

void creditar(int valor) { 
    pthread_mutex_lock(&saldo_mutex); // Bloqueia o mutex
    int tmp_saldo = saldo;

    sleep(1); // Delay simulado

    saldo = tmp_saldo + valor;

    pthread_mutex_unlock(&saldo_mutex); // Libera o mutex
}

void debitar(int valor) {
    pthread_mutex_lock(&saldo_mutex); // Bloqueia o mutex
    int tmp_saldo = saldo;

    sleep(1); // Delay simulado

    if (tmp_saldo >= valor) {
        saldo = tmp_saldo - valor;
    }

    pthread_mutex_unlock(&saldo_mutex);  // Libera o mutex
}

Rust? ??? ??? ?? ??? ???? ?? ????? ???, ???? ? ????? ??? ? ??? ??? ?? ??? ??? ?????? ??? ????? ??? ? ????.

Rust? ???, ?? ? ???? ??? ?? ? ?? ??? ???? ??? ?? ???? ?? ??

? ?????.

• Arc: ?? ???? ???? ?????.
• Mutex ? RwLock: ?? ??? ???? ?? ??? ??

4.1. ?? ?? ??

Arc ? Mutex ???? ???? ??

Rust’s rich type system and ownership model guarantee memory-safety and thread-safety — enabling you to eliminate many classes of bugs at compile-time.

Rust? ?? ?? ?? ????? ?? ??? ???(??)? ?? ????? ?? ???? ????.
??? ???? ?? ???? ?? ???(handle1 ? handle2)? ???? ??? ?????? ??? ?????.
???? ?? ???? ??? ????.

fn main() {
    let mut saldo = 1000; // saldo mutável, mas sem prote??o

    let handle1 = thread::spawn(move || {
        saldo += 100;  // erro: `saldo` é movido para esta thread sem prote??o
    });

    let handle2 = thread::spawn(move || {
        saldo -= 50;  // erro: `saldo` é movido para esta thread sem prote??o
    });

    handle1.join().unwrap();
    handle2.join().unwrap();
}

4.2. Mutex ? Arc? ??? ??

Mutex? Arc? ???? ?? ?? ??? ????? ??? ????? ??? ? ?????.

error[E0382]: use of moved value: `saldo`

4.3. ??? ? RwLock

Mutex? RwLock? ?? ??? ???? ? ???? ?? ??? ?? ??? ????.

???: ? ???? ???? ?? ?? ???? ???? ?? ???? ??? ??? ?? ???? ???? ?????. ???? ?????? ??? ???? ????? ??? ?? ??????? ???? ?????.

RwLock: .read()? ???? ?? ?? ??? ???? .write()? ???? ?? ??? ?????. ?? ???? ?? ??? ???? ??? ?????? ??? ??? ????? ??????.

---

5. ??

C? Rust? ??? ?? ??? ???? ??? ?? ??? ?????. C??? ?? ?? ??? ???? ?? ??? ????? Rust? ??? ?? ??? Mutex, RwLock ? Arc? ?? ??? ?? ??? ??? ??? ??? ????. ?? ??? ?? ???? ?? ?? ???, ??? ??? ???? ?????? ??? ??? ?????

.

????? Rust? ?? ???? ???? ??? ???? ???? ??? ?????.

---

6. ????

• ??? ??? ???: https://github.com/z4nder/rust-data-races
• https://en.wikipedia.org/wiki/Race_condition
• https://blog.bughunt.com.br/o-que-sao-vulnerabilidades-race-condition/
• https://medium.com/cwi-software/spring-boot-race-condition-e-ambiente-multi-thread-263b21e0042e
• https://learn.microsoft.com/en-us/troubleshoot/developer/visualstudio/visual-basic/??-compilers/race-conditions-deadlocks
• https://www.reddit.com/r/rust/comments/18faxjg/understanding_threadsafety_vs_race_conditions/?rdt=52263
• https://doc.rust-lang.org/nomicon/races.html
• https://news.ycombinator.com/item?id=23599598

? ??? Rust Threads ???: C?? ??.? ?? ?????. ??? ??? PHP ??? ????? ?? ?? ??? ?????!