add new API

docs.md

@@ -659,6 +659,19 @@ Get the timer repeat value.
 
 **Returns:** `integer`
 
+### `uv.timer_get_due_in(timer)`
+
+> method form `timer:get_due_in()`
+
+**Parameters:**
+- `timer`: `uv_timer_t userdata`
+
+Get the timer due value or 0 if it has expired. The time is relative to `uv.now()`.
+
+**Returns:** `integer`
+
+**Note**: New in libuv version 1.40.0.
+
 ## `uv_prepare_t` — Prepare handle
 
 [`uv_prepare_t`]: #uv_prepare_t--prepare-handle

src/luv.c

@@ -93,6 +93,9 @@ static const luaL_Reg luv_functions[] = {
   {"timer_again", luv_timer_again},
   {"timer_set_repeat", luv_timer_set_repeat},
   {"timer_get_repeat", luv_timer_get_repeat},
+#if LUV_UV_VERSION_GEQ(1, 40, 0)
+  {"timer_get_due_in", luv_timer_get_due_in},
+#endif
 
   // prepare.c
   {"new_prepare", luv_new_prepare},
@@ -506,6 +509,9 @@ static const luaL_Reg luv_timer_methods[] = {
   {"again", luv_timer_again},
   {"set_repeat", luv_timer_set_repeat},
   {"get_repeat", luv_timer_get_repeat},
+#if LUV_UV_VERSION_GEQ(1, 40, 0)
+  {"get_due_in", luv_timer_get_due_in},
+#endif
   {NULL, NULL}
 };
 

src/timer.c

@@ -77,3 +77,13 @@ static int luv_timer_get_repeat(lua_State* L) {
   lua_pushinteger(L, repeat);
   return 1;
 }
+
+#if LUV_UV_VERSION_GEQ(1, 40, 0)
+static int luv_timer_get_due_in(lua_State* L) {
+  uv_timer_t* handle = luv_check_timer(L, 1);
+  uint64_t val = uv_timer_get_due_in(handle);
+  lua_pushinteger(L, val);
+  return 1;
+}
+#endif
+

tests/test-timer.lua

@@ -84,4 +84,27 @@ return require('lib/tap')(function (test)
     end, 4))
   end)
 
+  test("timer init", function(print, p, expect, uv)
+    local timer = uv.new_timer()
+    assert(timer:get_repeat()==0)
+    assert(timer:get_due_in()>=0)
+    assert(timer:is_active()==false)
+    uv.close(timer)
+  end)
+
+  test("timer huge timeout", function(print, p, expect, uv)
+    local tiny_timer = uv.new_timer()
+    local huge_timer = uv.new_timer()
+
+    local function timer_cb()
+      uv.close(tiny_timer)
+      uv.close(huge_timer)
+    end
+
+    uv.timer_start(tiny_timer, 1, 0, expect(timer_cb))
+    uv.timer_start(huge_timer, 0xfffffffffff, 0, timer_cb)
+    assert(tiny_timer:get_due_in()==1)
+    assert(huge_timer:get_due_in()==0xfffffffffff)
+  end)
+
 end)