hello-world-cpp/task_3/counter_manager.cpp

#include "counter_manager.h"






long long int CounterManager::get_counter() {
    char data_from_file[128];
    int num_bytes = 128;

    int fd = open(
        "counter.txt",
        O_RDONLY,
        0777
    );
    if (fd == -1) {
        return 0; // Ошибка при открытии файла
    }
    
    read(fd, data_from_file, num_bytes);

    close(fd); 

    return atoi(data_from_file);
}


int CounterManager::set_counter(long long int new_counter) {
    long long int current_timestamp = MyTime::get_timestamp(), foreign_timestamp;
    std::string queue_directory = "queue";
    std::string queue_member = std::to_string(current_timestamp) + "_" + std::to_string(getpid()) + ".txt";
    std::string queue_member_path = queue_directory + "/" + queue_member;

    std::string filename, temp_str;


    int queue_member_fd = open(queue_member_path.c_str(), O_WRONLY | O_CREAT | O_TRUNC, 0777);
    if (queue_member_fd == -1) { // Если ошибка при открытии
        std::cerr << "queue member can't be created" << std::endl;
        return -1;
    }
    close(queue_member_fd);

    // std::cout << queue_member << " created" << "\n";

    bool start_operation = 0;
    DIR* dir;
    struct dirent* entry;

    while (!start_operation) {
        usleep((useconds_t)(100 * 1000));
        // std::cout << queue_member << " wait" << "\n";

        dir = opendir(queue_directory.c_str());
        
        start_operation = 1;
        while ((entry = readdir(dir)) != nullptr) {
            // Исключаем "." и ".."
            filename = std::string(entry->d_name);
            if (filename == "." || filename == "..") {
                continue;
            }
            // std::cout << queue_member << " file prev: " << filename << "\n";
            temp_str = "";
            for (char sym : filename) {
                if (sym == '_') {
                    break;
                }
                temp_str += sym;
            }
            foreign_timestamp = atoll(temp_str.c_str());
            if (foreign_timestamp < current_timestamp) {
                start_operation = 0;
                break;
            }
    }
    }


    std::string new_counter_string = std::to_string(new_counter);
    int fd = open(
        "counter.txt",
        O_WRONLY|O_TRUNC|O_APPEND|O_CREAT,
        0777
    );
    if (fd == -1) {
        return -1; // Ошибка при открытии файла
    }

    write(fd, new_counter_string.c_str(), new_counter_string.length());
    close(fd);


    int status = remove(queue_member_path.c_str());
    if (status != 0) {
        perror("Error deleting file");
    }

    // std::cout << queue_member << " deleted" << "\n";

    return 0;
}