thetinygoat / guava

A dead simple event loop library written in C

Guava

Guava is a simple to use event loop library written in C. It aims to provide a thin abstraction over platform APIs.

Status

Guava is currently under active development and should not be used in production.

Features

Currently Guava supports file descriptor events and time events, file system events are currently not supported but I am planning to implement a thread pool to support those as well, though it is not an immediate priority. Currently I'm focussing on adding more backends and stabilizing the system.

Examples

Fully working code can be found in the examples directory.

Timers

int interval_callback(GuavaLoop *loop, int id, void *data) {
    printf("interval callback called for time event %d\n", id);

    return 100;
}

int timeout_callback(GuavaLoop *loop, int id, void *data) {
    printf("timeout callback called for time event %d\n", id);

    return GUAVA_STOP_TIMER;
}

int main() {
    GuavaLoop *loop = guava_create_loop(1024);
    guava_create_time_event(loop, 1000, NULL, interval_callback);
    guava_create_time_event(loop, 10000, NULL, timeout_callback);
    guava_start_loop(loop);
    guava_delete_loop(loop);
    return 0;
}

interval callback called for time event 0
interval callback called for time event 0
interval callback called for time event 0
interval callback called for time event 0
interval callback called for time event 0
interval callback called for time event 0
interval callback called for time event 0
interval callback called for time event 0
interval callback called for time event 0
timeout callback called for time event 1

TCP Server

void callback(GuavaLoop *loop, int fd, int mask, void *data) {
    struct sockaddr_storage incoming;
    socklen_t size = sizeof(incoming);
    printf("new connection\n");
    int conn_fd = accept(fd, (struct sockaddr *)&incoming, &size);
    if (conn_fd == -1) {
        return;
    }
}

int main() {
    struct addrinfo hints;
    struct addrinfo *serv;

    memset(&hints, 0, sizeof(hints));

    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_flags = AI_PASSIVE;

    int status = getaddrinfo(NULL, "8080", &hints, &serv);

    if (status != 0) {
        exit(1);
    }

    int sock_fd = socket(serv->ai_family, serv->ai_socktype, serv->ai_protocol);

    if (sock_fd == -1) {
        exit(1);
    }

    int res = bind(sock_fd, serv->ai_addr, serv->ai_addrlen);

    if (res == -1) {
        exit(1);
    }

    int res1 = listen(sock_fd, 5);

    if (res1 == -1) {
        exit(1);
    }

    GuavaLoop *loop = guava_create_loop(1024);
    guava_create_fd_event(loop, sock_fd, GUAVA_READABLE, NULL, callback);
    guava_start_loop(loop);
    guava_delete_loop(loop);
    close(sock_fd);

    return 0;
}

new connection
new connection

Supported Backend

1. Kqueue - On macOS and BSD systems
2. Poll - On rest of the unix platforms
3. Epoll - Under development

The best backend for your system is automatically identified and used by Guava.