feat: introduce uv.metrics_info api

src/luv.c

@@ -392,6 +392,9 @@ static const luaL_Reg luv_functions[] = {
 #if LUV_UV_VERSION_GEQ(1, 39, 0)
   {"metrics_idle_time", luv_metrics_idle_time},
 #endif
+#if LUV_UV_VERSION_GEQ(1, 45, 0)
+  {"metrics_info", luv_metrics_info},
+#endif
 
   {NULL, NULL}
 };

src/metrics.c

@@ -25,3 +25,27 @@ static int luv_metrics_idle_time(lua_State* L) {
   return 1;
 }
 #endif
+
+#if LUV_UV_VERSION_GEQ(1, 45, 0)
+static int luv_metrics_info(lua_State *L) {
+  uv_metrics_t metrics;
+  int ret = uv_metrics_info(luv_loop(L), &metrics);
+  if (ret < 0) return luv_error(L, ret);
+
+  lua_newtable(L);
+
+  lua_pushliteral(L, "loop_count");
+  lua_pushinteger(L, metrics.loop_count);
+  lua_rawset(L, -3);
+
+  lua_pushliteral(L, "events");
+  lua_pushinteger(L, metrics.events);
+  lua_rawset(L, -3);
+
+  lua_pushliteral(L, "events_waiting");
+  lua_pushinteger(L, metrics.events_waiting);
+  lua_rawset(L, -3);
+
+  return 1;
+}
+#endif

tests/test-metrics.lua

@@ -0,0 +1,31 @@
+
+return require('lib/tap')(function (test)
+
+  test("idle time", function (print, p, expect, uv)
+    local NS_TO_MS = 1000000
+    local timeout = 1000
+    local timer = uv.new_timer()
+    local counter = 0
+    timer:start(timeout, 0, function()
+      counter = counter + 1
+      local t = uv.hrtime()
+
+      -- Spin for 500 ms to spin loop time out of the delta check.
+      while uv.hrtime() - t < 600 * NS_TO_MS do end
+      timer:close()
+
+      local metrics = uv.metrics_info()
+      p(metrics)
+      assert(metrics.loop_count > 0)
+      assert(metrics.events >= 0)
+      assert(metrics.events_waiting >= 0)
+    end)
+
+    local metrics = assert(uv.metrics_info())
+    p(metrics)
+    assert(metrics.loop_count >= 0)
+    assert(metrics.events >= 0)
+    assert(metrics.events_waiting >= 0)
+  end, "1.45.0")
+
+end)