event_queue.c

#include <pthread.h>
#include <stdbool.h>
#include <stdlib.h>

#include "event_queue.h"

#ifndef QUEUE_CAPACITY
#define QUEUE_CAPACITY 32
#endif

typedef struct {
    event queue[QUEUE_CAPACITY];
    int in;
    int out;
    pthread_mutex_t mtx;
    pthread_cond_t cond;
    bool quit;
} queue;

static queue q = {.in = 0, .out = 0};

void queue_init(void) {
    pthread_mutex_init(&(q.mtx), NULL);
    pthread_cond_init(&(q.cond), NULL);
}

void queue_cleanup(void) {
    while (q.in != q.out) {
        event ev = queue_pop();
        if (ev.data.msg) {
            free(ev.data.msg);
        }
    }
}

event queue_pop(void) {
    event ev = {.type = EV_TYPE_NUM};
    pthread_mutex_lock(&(q.mtx));
    while (!q.quit && q.in == q.out) {
        pthread_cond_wait(&(q.cond), &(q.mtx));
    }
    if (q.in != q.out) {
        ev = q.queue[q.out];
        q.out = (q.out + 1) % QUEUE_CAPACITY;
        pthread_cond_broadcast(&(q.cond));
    }
    pthread_mutex_unlock(&(q.mtx));
    return ev;
}

void queue_push(event ev) {
    pthread_mutex_lock(&(q.mtx));
    while (((q.in + 1) % QUEUE_CAPACITY) == q.out) {
        pthread_cond_wait(&(q.cond), &(q.mtx));
    }
    q.queue[q.in] = ev;
    q.in = (q.in + 1) % QUEUE_CAPACITY;
    pthread_cond_broadcast(&(q.cond));
    pthread_mutex_unlock(&(q.mtx));
}

bool is_quit() {
    bool quit;
    pthread_mutex_lock(&(q.mtx));
    quit = q.quit;
    pthread_mutex_unlock(&(q.mtx));
    return quit;
}

void set_quit() {
    pthread_mutex_lock(&(q.mtx));
    q.quit = true;
    pthread_mutex_unlock(&(q.mtx));
}