src: prevent extra copies of `TimerWrap::TimerCb`

I noticed that we were taking `TimerCb` as a `const&` and then copying
that into the member. This is completely fine when the constructor is
called with an lvalue. However, when called with an rvalue, we can allow
the `std::function` to be moved into the member instead of falling back
to a copy, so I changed the constructors to take in universal
references. Also, `std::function` constructors can take in multiple
arguments, so I further modified the constructors to use variadic
templates.

Signed-off-by: Darshan Sen <darshan.sen@postman.com>

PR-URL: https://github.com/nodejs/node/pull/40665
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Minwoo Jung <nodecorelab@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>

1 files changed, 5 insertions, 4 deletions

diff --git a/src/timer_wrap.h b/src/timer_wrap.h
index dbc23b442be..ac8f00f0d47 100644
--- a/src/timer_wrap.h
+++ b/src/timer_wrap.h
@@ -16,7 +16,9 @@ class TimerWrap final : public MemoryRetainer {
  public:
   using TimerCb = std::function<void()>;
 
-  TimerWrap(Environment* env, const TimerCb& fn);
+  template <typename... Args>
+  explicit inline TimerWrap(Environment* env, Args&&... args);
+
   TimerWrap(const TimerWrap&) = delete;
 
   inline Environment* env() const { return env_; }
@@ -50,9 +52,8 @@ class TimerWrap final : public MemoryRetainer {
 
 class TimerWrapHandle : public MemoryRetainer  {
  public:
-  TimerWrapHandle(
-      Environment* env,
-      const TimerWrap::TimerCb& fn);
+  template <typename... Args>
+  explicit inline TimerWrapHandle(Environment* env, Args&&... args);
 
   TimerWrapHandle(const TimerWrapHandle&) = delete;