test-async.c

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 *
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 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
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#include "uv.h"
#include "task.h"
#include <stdio.h>
#include <stdlib.h>
 
static uv_thread_t thread;
static uv_mutex_t mutex;
 
static uv_prepare_t prepare;
static uv_async_t async;
 
static volatile int async_cb_called;
static int prepare_cb_called;
static int close_cb_called;
 
 
static void thread_cb(void *arg) {
  int n;
  int r;
 
  for (;;) {
    uv_mutex_lock(&mutex);
    n = async_cb_called;
    uv_mutex_unlock(&mutex);
 
    if (n == 3) {
      break;
    }
 
    r = uv_async_send(&async);
    ASSERT(r == 0);
 
    /* Work around a bug in Valgrind.
     *
     * Valgrind runs threads not in parallel but sequentially, i.e. one after
     * the other. It also doesn't preempt them, instead it depends on threads
     * yielding voluntarily by making a syscall.
     *
     * That never happens here: the pipe that is associated with the async
     * handle is written to once but that's too early for Valgrind's scheduler
     * to kick in. Afterwards, the thread busy-loops, starving the main thread.
     * Therefore, we yield.
     *
     * This behavior has been observed with Valgrind 3.7.0 and 3.9.0.
     */
    uv_sleep(0);
  }
}
 
 
static void close_cb(uv_handle_t* handle) {
  ASSERT(handle != NULL);
  close_cb_called++;
}
 
 
static void async_cb(uv_async_t* handle) {
  int n;
 
  ASSERT(handle == &async);
 
  uv_mutex_lock(&mutex);
  n = ++async_cb_called;
  uv_mutex_unlock(&mutex);
 
  if (n == 3) {
    uv_close((uv_handle_t*)&async, close_cb);
    uv_close((uv_handle_t*)&prepare, close_cb);
  }
}
 
 
static void prepare_cb(uv_prepare_t* handle) {
  int r;
 
  ASSERT(handle == &prepare);
 
  if (prepare_cb_called++)
    return;
 
  r = uv_thread_create(&thread, thread_cb, NULL);
  ASSERT(r == 0);
  uv_mutex_unlock(&mutex);
}
 
 
TEST_IMPL(async) {
  int r;
 
  r = uv_mutex_init(&mutex);
  ASSERT(r == 0);
  uv_mutex_lock(&mutex);
 
  r = uv_prepare_init(uv_default_loop(), &prepare);
  ASSERT(r == 0);
  r = uv_prepare_start(&prepare, prepare_cb);
  ASSERT(r == 0);
 
  r = uv_async_init(uv_default_loop(), &async, async_cb);
  ASSERT(r == 0);
 
  r = uv_run(uv_default_loop(), UV_RUN_DEFAULT);
  ASSERT(r == 0);
 
  ASSERT(prepare_cb_called > 0);
  ASSERT(async_cb_called == 3);
  ASSERT(close_cb_called == 2);
 
  ASSERT(0 == uv_thread_join(&thread));
 
  MAKE_VALGRIND_HAPPY();
  return 0;
}