feat: implement concurrent worker queue

src/loop/lnm_loop_worker.c

@@ -0,0 +1,61 @@
+#include "lnm/loop.h"
+
+lnm_err lnm_loop_queue_init(lnm_loop_queue **out, size_t cap) {
+  lnm_loop_conn **arr = malloc(cap * sizeof(lnm_loop_conn *));
+
+  if (arr == NULL) {
+    return lnm_err_failed_alloc;
+  }
+
+  lnm_loop_queue *q = calloc(1, sizeof(lnm_loop_queue));
+
+  if (q == NULL) {
+    free(arr);
+
+    return lnm_err_failed_alloc;
+  }
+
+  q->buf.arr = arr;
+  q->buf.len = cap;
+
+  pthread_mutex_init(&q->mutex, NULL);
+  pthread_cond_init(&q->cond, NULL);
+
+  *out = q;
+
+  return lnm_err_ok;
+}
+
+void lnm_loop_queue_push(lnm_loop_queue *q, lnm_loop_conn *conn) {
+  pthread_mutex_lock(&q->mutex);
+
+  while (q->tail == q->head) {
+    pthread_cond_wait(&q->cond, &q->mutex);
+  }
+
+  q->buf.arr[q->tail] = conn;
+
+  // Make sure the index wraps around
+  q->tail = (q->tail + 1) % q->buf.len;
+
+  // Unlock mutex and signal to waiting threads
+  pthread_mutex_unlock(&q->mutex);
+  pthread_cond_signal(&q->cond);
+}
+
+lnm_loop_conn *lnm_loop_queue_pop(lnm_loop_queue *q) {
+  pthread_mutex_lock(&q->mutex);
+
+  while (q->tail == q->head) {
+    pthread_cond_wait(&q->cond, &q->mutex);
+  }
+
+  lnm_loop_conn *out = q->buf.arr[q->head];
+  q->head = (q->head + 1) % q->buf.len;
+
+  // Unlock mutex and signal to waiting threads
+  pthread_mutex_unlock(&q->mutex);
+  pthread_cond_signal(&q->cond);
+
+  return out;
+}