--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/third_party/libuv/test/test-metrics.c	Wed Jan 14 19:39:52 2026 -0800
@@ -0,0 +1,390 @@
+/* Copyright libuv project contributors. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * 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
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include "uv.h"
+#include "task.h"
+#include <string.h> /* memset */
+
+#define UV_NS_TO_MS 1000000
+
+typedef struct {
+  uv_fs_t open_req;
+  uv_fs_t write_req;
+  uv_fs_t close_req;
+} fs_reqs_t;
+
+static uint64_t last_events_count;
+static char test_buf[] = "test-buffer\n";
+static fs_reqs_t fs_reqs;
+static int pool_events_counter;
+
+
+static void timer_spin_cb(uv_timer_t* handle) {
+  uint64_t t;
+
+  (*(int*) handle->data)++;
+  t = uv_hrtime();
+  /* Spin for 500 ms to spin loop time out of the delta check. */
+  while (uv_hrtime() - t < 600 * UV_NS_TO_MS) { }
+}
+
+
+TEST_IMPL(metrics_idle_time) {
+#if defined(__OpenBSD__)
+  RETURN_SKIP("Test does not currently work in OpenBSD");
+#endif
+  const uint64_t timeout = 1000;
+  uv_timer_t timer;
+  uint64_t idle_time;
+  int cntr;
+
+  cntr = 0;
+  timer.data = &cntr;
+
+  ASSERT_OK(uv_loop_configure(uv_default_loop(), UV_METRICS_IDLE_TIME));
+  ASSERT_OK(uv_timer_init(uv_default_loop(), &timer));
+  ASSERT_OK(uv_timer_start(&timer, timer_spin_cb, timeout, 0));
+
+  ASSERT_OK(uv_run(uv_default_loop(), UV_RUN_DEFAULT));
+  ASSERT_GT(cntr, 0);
+
+  idle_time = uv_metrics_idle_time(uv_default_loop());
+
+  /* Permissive check that the idle time matches within the timeout ±500 ms. */
+  ASSERT_LE(idle_time, (timeout + 500) * UV_NS_TO_MS);
+  ASSERT_GE(idle_time, (timeout - 500) * UV_NS_TO_MS);
+
+  MAKE_VALGRIND_HAPPY(uv_default_loop());
+  return 0;
+}
+
+
+static void metrics_routine_cb(void* arg) {
+  const uint64_t timeout = 1000;
+  uv_loop_t loop;
+  uv_timer_t timer;
+  uint64_t idle_time;
+  int cntr;
+
+  cntr = 0;
+  timer.data = &cntr;
+
+  ASSERT_OK(uv_loop_init(&loop));
+  ASSERT_OK(uv_loop_configure(&loop, UV_METRICS_IDLE_TIME));
+  ASSERT_OK(uv_timer_init(&loop, &timer));
+  ASSERT_OK(uv_timer_start(&timer, timer_spin_cb, timeout, 0));
+
+  ASSERT_OK(uv_run(&loop, UV_RUN_DEFAULT));
+  ASSERT_GT(cntr, 0);
+
+  idle_time = uv_metrics_idle_time(&loop);
+
+  /* Only checking that idle time is greater than the lower bound since there
+   * may have been thread contention, causing the event loop to be delayed in
+   * the idle phase longer than expected.
+   */
+  ASSERT_GE(idle_time, (timeout - 500) * UV_NS_TO_MS);
+
+  close_loop(&loop);
+  ASSERT_OK(uv_loop_close(&loop));
+}
+
+
+TEST_IMPL(metrics_idle_time_thread) {
+  uv_thread_t threads[5];
+  int i;
+
+  for (i = 0; i < 5; i++) {
+    ASSERT_OK(uv_thread_create(&threads[i], metrics_routine_cb, NULL));
+  }
+
+  for (i = 0; i < 5; i++) {
+    uv_thread_join(&threads[i]);
+  }
+
+  return 0;
+}
+
+
+static void timer_noop_cb(uv_timer_t* handle) {
+  (*(int*) handle->data)++;
+}
+
+
+TEST_IMPL(metrics_idle_time_zero) {
+  uv_metrics_t metrics;
+  uv_timer_t timer;
+  int cntr;
+
+  cntr = 0;
+  timer.data = &cntr;
+  ASSERT_OK(uv_loop_configure(uv_default_loop(), UV_METRICS_IDLE_TIME));
+  ASSERT_OK(uv_timer_init(uv_default_loop(), &timer));
+  ASSERT_OK(uv_timer_start(&timer, timer_noop_cb, 0, 0));
+
+  ASSERT_OK(uv_run(uv_default_loop(), UV_RUN_DEFAULT));
+
+  ASSERT_GT(cntr, 0);
+  ASSERT_OK(uv_metrics_idle_time(uv_default_loop()));
+
+  ASSERT_OK(uv_metrics_info(uv_default_loop(), &metrics));
+  ASSERT_UINT64_EQ(cntr, metrics.loop_count);
+
+  MAKE_VALGRIND_HAPPY(uv_default_loop());
+  return 0;
+}
+
+
+static void close_cb(uv_fs_t* req) {
+  uv_metrics_t metrics;
+
+  ASSERT_OK(uv_metrics_info(uv_default_loop(), &metrics));
+  ASSERT_UINT64_EQ(3, metrics.loop_count);
+  ASSERT_UINT64_GT(metrics.events, last_events_count);
+
+  uv_fs_req_cleanup(req);
+  last_events_count = metrics.events;
+}
+
+
+static void write_cb(uv_fs_t* req) {
+  uv_metrics_t metrics;
+
+  ASSERT_OK(uv_metrics_info(uv_default_loop(), &metrics));
+  ASSERT_UINT64_EQ(2, metrics.loop_count);
+  ASSERT_UINT64_GT(metrics.events, last_events_count);
+  ASSERT_EQ(req->result, sizeof(test_buf));
+
+  uv_fs_req_cleanup(req);
+  last_events_count = metrics.events;
+
+  ASSERT_OK(uv_fs_close(uv_default_loop(),
+                        &fs_reqs.close_req,
+                        fs_reqs.open_req.result,
+                        close_cb));
+}
+
+
+static void create_cb(uv_fs_t* req) {
+  uv_metrics_t metrics;
+
+  ASSERT_OK(uv_metrics_info(uv_default_loop(), &metrics));
+  /* Event count here is still 0 so not going to check. */
+  ASSERT_UINT64_EQ(1, metrics.loop_count);
+  ASSERT_GE(req->result, 0);
+
+  uv_fs_req_cleanup(req);
+  last_events_count = metrics.events;
+
+  uv_buf_t iov = uv_buf_init(test_buf, sizeof(test_buf));
+  ASSERT_OK(uv_fs_write(uv_default_loop(),
+                        &fs_reqs.write_req,
+                        req->result,
+                        &iov,
+                        1,
+                        0,
+                        write_cb));
+}
+
+
+static void prepare_cb(uv_prepare_t* handle) {
+  uv_metrics_t metrics;
+
+  uv_prepare_stop(handle);
+
+  ASSERT_OK(uv_metrics_info(uv_default_loop(), &metrics));
+  ASSERT_UINT64_EQ(0, metrics.loop_count);
+  ASSERT_UINT64_EQ(0, metrics.events);
+
+  ASSERT_OK(uv_fs_open(uv_default_loop(),
+                       &fs_reqs.open_req,
+                       "test_file",
+                       UV_FS_O_WRONLY | UV_FS_O_CREAT, S_IRUSR | S_IWUSR,
+                       create_cb));
+}
+
+
+TEST_IMPL(metrics_info_check) {
+  uv_fs_t unlink_req;
+  uv_prepare_t prepare;
+
+  uv_fs_unlink(NULL, &unlink_req, "test_file", NULL);
+  uv_fs_req_cleanup(&unlink_req);
+
+  ASSERT_OK(uv_prepare_init(uv_default_loop(), &prepare));
+  ASSERT_OK(uv_prepare_start(&prepare, prepare_cb));
+
+  ASSERT_OK(uv_run(uv_default_loop(), UV_RUN_DEFAULT));
+
+  uv_fs_unlink(NULL, &unlink_req, "test_file", NULL);
+  uv_fs_req_cleanup(&unlink_req);
+
+  MAKE_VALGRIND_HAPPY(uv_default_loop());
+  return 0;
+}
+
+
+static void fs_prepare_cb(uv_prepare_t* handle) {
+  uv_metrics_t metrics;
+
+  ASSERT_OK(uv_metrics_info(uv_default_loop(), &metrics));
+
+  if (pool_events_counter == 1)
+    ASSERT_EQ(metrics.events, metrics.events_waiting);
+
+  if (pool_events_counter < 7)
+    return;
+
+  uv_prepare_stop(handle);
+  pool_events_counter = -42;
+}
+
+
+static void fs_stat_cb(uv_fs_t* req) {
+  uv_fs_req_cleanup(req);
+  pool_events_counter++;
+}
+
+
+static void fs_work_cb(uv_work_t* req) {
+}
+
+
+static void fs_after_work_cb(uv_work_t* req, int status) {
+  free(req);
+  pool_events_counter++;
+}
+
+
+static void fs_write_cb(uv_fs_t* req) {
+  uv_work_t* work1 = malloc(sizeof(*work1));
+  uv_work_t* work2 = malloc(sizeof(*work2));
+  pool_events_counter++;
+
+  uv_fs_req_cleanup(req);
+
+  ASSERT_OK(uv_queue_work(uv_default_loop(),
+                          work1,
+                          fs_work_cb,
+                          fs_after_work_cb));
+  ASSERT_OK(uv_queue_work(uv_default_loop(),
+                          work2,
+                          fs_work_cb,
+                          fs_after_work_cb));
+}
+
+
+static void fs_random_cb(uv_random_t* req, int status, void* buf, size_t len) {
+  pool_events_counter++;
+}
+
+
+static void fs_addrinfo_cb(uv_getaddrinfo_t* req,
+                           int status,
+                           struct addrinfo* res) {
+  uv_freeaddrinfo(req->addrinfo);
+  pool_events_counter++;
+}
+
+
+TEST_IMPL(metrics_pool_events) {
+  uv_buf_t iov;
+  uv_fs_t open_req;
+  uv_fs_t stat1_req;
+  uv_fs_t stat2_req;
+  uv_fs_t unlink_req;
+  uv_fs_t write_req;
+  uv_getaddrinfo_t addrinfo_req;
+  uv_metrics_t metrics;
+  uv_prepare_t prepare;
+  uv_random_t random_req;
+  int fd;
+  char rdata;
+
+  ASSERT_OK(uv_loop_configure(uv_default_loop(), UV_METRICS_IDLE_TIME));
+
+  uv_fs_unlink(NULL, &unlink_req, "test_file", NULL);
+  uv_fs_req_cleanup(&unlink_req);
+
+  ASSERT_OK(uv_prepare_init(uv_default_loop(), &prepare));
+  ASSERT_OK(uv_prepare_start(&prepare, fs_prepare_cb));
+
+  pool_events_counter = 0;
+  fd = uv_fs_open(NULL,
+                  &open_req, "test_file", UV_FS_O_WRONLY | UV_FS_O_CREAT,
+                  S_IRUSR | S_IWUSR,
+                  NULL);
+  ASSERT_GT(fd, 0);
+  uv_fs_req_cleanup(&open_req);
+
+  iov = uv_buf_init(test_buf, sizeof(test_buf));
+  ASSERT_OK(uv_fs_write(uv_default_loop(),
+                        &write_req,
+                        fd,
+                        &iov,
+                        1,
+                        0,
+                        fs_write_cb));
+  ASSERT_OK(uv_fs_stat(uv_default_loop(),
+                       &stat1_req,
+                       "test_file",
+                       fs_stat_cb));
+  ASSERT_OK(uv_fs_stat(uv_default_loop(),
+                       &stat2_req,
+                       "test_file",
+                       fs_stat_cb));
+  ASSERT_OK(uv_random(uv_default_loop(),
+                      &random_req,
+                      &rdata,
+                      1,
+                      0,
+                      fs_random_cb));
+  ASSERT_OK(uv_getaddrinfo(uv_default_loop(),
+                           &addrinfo_req,
+                           fs_addrinfo_cb,
+                           "example.invalid",
+                           NULL,
+                           NULL));
+
+  /* Sleep for a moment to hopefully force the events to complete before
+   * entering the event loop. */
+  uv_sleep(100);
+
+  ASSERT_OK(uv_run(uv_default_loop(), UV_RUN_DEFAULT));
+
+  ASSERT_OK(uv_metrics_info(uv_default_loop(), &metrics));
+  /* It's possible for uv__work_done() to execute one extra time even though the
+   * QUEUE has already been cleared out. This has to do with the way we use an
+   * uv_async to tell the event loop thread to process the worker pool QUEUE. */
+  ASSERT_GE(metrics.events, 7);
+  /* It's possible one of the other events also got stuck in the event queue, so
+   * check GE instead of EQ. Reason for 4 instead of 5 is because the call to
+   * uv_getaddrinfo() is racey and slow. So can't guarantee that it'll always
+   * execute before sleep completes. */
+  ASSERT_GE(metrics.events_waiting, 4);
+  ASSERT_EQ(pool_events_counter, -42);
+
+  uv_fs_unlink(NULL, &unlink_req, "test_file", NULL);
+  uv_fs_req_cleanup(&unlink_req);
+
+  MAKE_VALGRIND_HAPPY(uv_default_loop());
+  return 0;
+}