src: add TimerWrap utility

Consolidate uv_timer_t boilerplate code into a shared utility. There are several places throughout the code where we use uv_timer_t internally (inspector, perf, quic), with some code duplication. This eliminates the duplicated code, ensures that cleanup occurs correctly, and simplifies use of the timers. Signed-off-by: James M Snell <jasnell@gmail.com>
nodejs · jasnell · Jul 3, 2020 · Jul 3, 2020 · Jul 3, 2020 · Jul 5, 2020
commit 9707be185e01984948526aa12de64924b43f3e41
diff --git a/node.gyp b/node.gyp
@@ -638,6 +638,7 @@
         'src/string_decoder.cc',
         'src/tcp_wrap.cc',
         'src/timers.cc',
+        'src/timer_wrap.cc',
         'src/tracing/agent.cc',
         'src/tracing/node_trace_buffer.cc',
         'src/tracing/node_trace_writer.cc',
@@ -741,6 +742,7 @@
         'src/tracing/trace_event.h',
         'src/tracing/trace_event_common.h',
         'src/tracing/traced_value.h',
+        'src/timer_wrap.h',
         'src/tty_wrap.h',
         'src/udp_wrap.h',
         'src/util.h',

diff --git a/src/timer_wrap.cc b/src/timer_wrap.cc
@@ -0,0 +1,94 @@
+#include "env-inl.h"
+#include "memory_tracker-inl.h"
+#include "timer_wrap.h"
+#include "uv.h"
+
+namespace node {
+
+TimerWrap::TimerWrap(Environment* env, TimerCb fn, void* user_data)
+    : env_(env),
+      fn_(fn),
+      user_data_(user_data) {
+  uv_timer_init(env->event_loop(), &timer_);
+  timer_.data = this;
+}
+
+void TimerWrap::Stop(bool close) {
+  if (timer_.data == nullptr) return;
+  uv_timer_stop(&timer_);
+  if (LIKELY(close)) {
+    timer_.data = nullptr;
+    env_->CloseHandle(reinterpret_cast<uv_handle_t*>(&timer_), TimerClosedCb);
+  }
+}
+
+void TimerWrap::TimerClosedCb(uv_handle_t* handle) {
+  std::unique_ptr<TimerWrap> ptr(
+      ContainerOf(&TimerWrap::timer_,
+                  reinterpret_cast<uv_timer_t*>(handle)));
+}
+
+void TimerWrap::Update(uint64_t interval, uint64_t repeat) {
+  if (timer_.data == nullptr) return;
+  uv_timer_start(&timer_, OnTimeout, interval, repeat);
+}
+
+void TimerWrap::Ref() {
+  if (timer_.data == nullptr) return;
+  uv_ref(reinterpret_cast<uv_handle_t*>(&timer_));
+}
+
+void TimerWrap::Unref() {
+  if (timer_.data == nullptr) return;
+  uv_unref(reinterpret_cast<uv_handle_t*>(&timer_));
+}
+
+void TimerWrap::OnTimeout(uv_timer_t* timer) {
+  TimerWrap* t = ContainerOf(&TimerWrap::timer_, timer);
+  t->fn_(t->user_data_);
+}
+
+TimerWrapHandle::TimerWrapHandle(
+    Environment* env,
+    TimerWrap::TimerCb fn,
+    void* user_data) {
+  timer_ = new TimerWrap(env, fn, user_data);
+  env->AddCleanupHook(CleanupHook, this);
+}
+
+void TimerWrapHandle::Stop(bool close) {
+  if (UNLIKELY(!close))
+    return timer_->Stop(close);
+
+  if (timer_ != nullptr) {
+    timer_->env()->RemoveCleanupHook(CleanupHook, this);
+    timer_->Stop();
+  }
+  timer_ = nullptr;
+}
+
+void TimerWrapHandle::Ref() {
+  if (timer_ != nullptr)
+    timer_->Ref();
+}
+
+void TimerWrapHandle::Unref() {
+  if (timer_ != nullptr)
+    timer_->Unref();
+}
+
+void TimerWrapHandle::Update(uint64_t interval, uint64_t repeat) {
+  if (timer_ != nullptr)
+    timer_->Update(interval, repeat);
+}
+
+void TimerWrapHandle::CleanupHook(void* data) {
+  static_cast<TimerWrapHandle*>(data)->Stop();
+}
+
+void TimerWrapHandle::MemoryInfo(node::MemoryTracker* tracker) const {
+  if (timer_ != nullptr)
+    tracker->TrackField("timer", *timer_);
+}
+
+}  // namespace node
diff --git a/src/timer_wrap.h b/src/timer_wrap.h
@@ -0,0 +1,84 @@
+#ifndef SRC_TIMER_WRAP_H_
+#define SRC_TIMER_WRAP_H_
+
+#if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
+
+#include "memory_tracker.h"
+#include "env.h"
+#include "uv.h"
+
+#include <functional>
+
+namespace node {
+
+// Utility class that makes working with libuv timers a bit easier.
+class TimerWrap final : public MemoryRetainer {
+ public:
+  using TimerCb = std::function<void(void*)>;
+
+  TimerWrap(Environment* env, TimerCb fn, void* user_data);
+  TimerWrap(const TimerWrap&) = delete;
+
+  inline Environment* env() const { return env_; }
+
+  // Completely stops the timer, making it no longer usable.
+  void Stop(bool close = true);
+
+  // Starts / Restarts the Timer
+  void Update(uint64_t interval, uint64_t repeat = 0);
+
+  void Ref();
+
+  void Unref();
+
+  SET_NO_MEMORY_INFO();
+  SET_MEMORY_INFO_NAME(TimerWrap)
+  SET_SELF_SIZE(TimerWrap)
+
+ private:
+  static void TimerClosedCb(uv_handle_t* handle);
+  static void OnTimeout(uv_timer_t* timer);
+  ~TimerWrap() = default;
+
+  Environment* env_;
+  TimerCb fn_;
+  uv_timer_t timer_;
+  void* user_data_ = nullptr;
+
+  friend std::unique_ptr<TimerWrap>::deleter_type;
+};
+
+class TimerWrapHandle : public MemoryRetainer  {
+ public:
+  TimerWrapHandle(
+      Environment* env,
+      TimerWrap::TimerCb fn,
+      void* user_data = nullptr);
+
+  TimerWrapHandle(const TimerWrapHandle&) = delete;
+
+  ~TimerWrapHandle() { Stop(); }
+
+  void Update(uint64_t interval, uint64_t repeat = 0);
+
+  void Ref();
+
+  void Unref();
+
+  void Stop(bool close = true);
+
+  void MemoryInfo(node::MemoryTracker* tracker) const override;
+
+  SET_MEMORY_INFO_NAME(TimerWrapHandle)
+  SET_SELF_SIZE(TimerWrapHandle)
+
+ private:
+  static void CleanupHook(void* data);
+  TimerWrap* timer_;
+};
+
+}  // namespace node
+
+#endif  // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
+
+#endif  // SRC_TIMER_WRAP_H_