src: split out callback queue implementation from Environment

This isn’t conceptually tied to anything Node.js-specific at all.

PR-URL: https://github.com/nodejs/node/pull/33272
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

1 files changed, 97 insertions, 0 deletions

diff --git a/src/callback_queue-inl.h b/src/callback_queue-inl.h
new file mode 100644
index 00000000000..e83c81cd0dd
--- /dev/null
+++ b/src/callback_queue-inl.h
@@ -0,0 +1,97 @@
+#ifndef SRC_CALLBACK_QUEUE_INL_H_
+#define SRC_CALLBACK_QUEUE_INL_H_
+
+#if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
+
+#include "callback_queue.h"
+
+namespace node {
+
+template <typename R, typename... Args>
+template <typename Fn>
+std::unique_ptr<typename CallbackQueue<R, Args...>::Callback>
+CallbackQueue<R, Args...>::CreateCallback(Fn&& fn, bool refed) {
+  return std::make_unique<CallbackImpl<Fn>>(std::move(fn), refed);
+}
+
+template <typename R, typename... Args>
+std::unique_ptr<typename CallbackQueue<R, Args...>::Callback>
+CallbackQueue<R, Args...>::Shift() {
+  std::unique_ptr<Callback> ret = std::move(head_);
+  if (ret) {
+    head_ = ret->get_next();
+    if (!head_)
+      tail_ = nullptr;  // The queue is now empty.
+  }
+  size_--;
+  return ret;
+}
+
+template <typename R, typename... Args>
+void CallbackQueue<R, Args...>::Push(std::unique_ptr<Callback> cb) {
+  Callback* prev_tail = tail_;
+
+  size_++;
+  tail_ = cb.get();
+  if (prev_tail != nullptr)
+    prev_tail->set_next(std::move(cb));
+  else
+    head_ = std::move(cb);
+}
+
+template <typename R, typename... Args>
+void CallbackQueue<R, Args...>::ConcatMove(CallbackQueue<R, Args...>&& other) {
+  size_ += other.size_;
+  if (tail_ != nullptr)
+    tail_->set_next(std::move(other.head_));
+  else
+    head_ = std::move(other.head_);
+  tail_ = other.tail_;
+  other.tail_ = nullptr;
+  other.size_ = 0;
+}
+
+template <typename R, typename... Args>
+size_t CallbackQueue<R, Args...>::size() const {
+  return size_.load();
+}
+
+template <typename R, typename... Args>
+CallbackQueue<R, Args...>::Callback::Callback(bool refed)
+  : refed_(refed) {}
+
+template <typename R, typename... Args>
+bool CallbackQueue<R, Args...>::Callback::is_refed() const {
+  return refed_;
+}
+
+template <typename R, typename... Args>
+std::unique_ptr<typename CallbackQueue<R, Args...>::Callback>
+CallbackQueue<R, Args...>::Callback::get_next() {
+  return std::move(next_);
+}
+
+template <typename R, typename... Args>
+void CallbackQueue<R, Args...>::Callback::set_next(
+    std::unique_ptr<Callback> next) {
+  next_ = std::move(next);
+}
+
+template <typename R, typename... Args>
+template <typename Fn>
+CallbackQueue<R, Args...>::CallbackImpl<Fn>::CallbackImpl(
+    Fn&& callback, bool refed)
+  : Callback(refed),
+    callback_(std::move(callback)) {}
+
+template <typename R, typename... Args>
+template <typename Fn>
+R CallbackQueue<R, Args...>::CallbackImpl<Fn>::Call(Args... args) {
+  return callback_(std::forward<Args>(args)...);
+}
+
+}  // namespace node
+
+#endif  // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
+
+#endif  // SRC_CALLBACK_QUEUE_INL_H_