refactor coroutine cancelled set

Author: netcan

include/asyncio/event_loop.h

@@ -8,7 +8,7 @@
 #include <asyncio/concept/future.h>
 #include <asyncio/selector/selector.h>
 #include <utility>
-#include <set>
+#include <unordered_set>
 #include <algorithm>
 #include <queue>
 #include <chrono>
@@ -17,10 +17,16 @@
 ASYNCIO_NS_BEGIN
 class EventLoop: private NonCopyable {
     using MSDuration = std::chrono::milliseconds;
+    // handle maybe destroyed, using the increasing id to track the lifetime of handle.
+    // don't directly using a raw pointer to track coroutine lifetime,
+    // because a destroyed coroutine may has the same address as a new ready coroutine has created.
+    struct HandleInfo {
+        HandleId id;
+        Handle* handle;
+    };
 
 public:
-    EventLoop() {
-        auto now = std::chrono::system_clock::now();
+    EventLoop() { auto now = std::chrono::system_clock::now();
         start_time_ = duration_cast<MSDuration>(now.time_since_epoch());
     }
 
@@ -29,6 +35,10 @@ class EventLoop: private NonCopyable {
         return duration_cast<MSDuration>(now.time_since_epoch()) - start_time_;
     }
 
+    HandleId allocate_handle_id() {
+        return handle_alloc_id_++;
+    }
+
     bool is_stop() {
         return schedule_.empty() && ready_.empty() && selector_.is_stop();
     }
@@ -41,17 +51,18 @@ class EventLoop: private NonCopyable {
     template<typename Rep, typename Period>
     void call_at(std::chrono::duration<Rep, Period> when, Handle& callback) {
         callback.set_state(PromiseState::PENDING);
-        schedule_.emplace_back(std::make_pair(duration_cast<MSDuration>(when), &callback));
+        schedule_.emplace_back(std::make_pair(duration_cast<MSDuration>(when),
+                    HandleInfo{callback.get_handle_id(), &callback}));
         std::ranges::push_heap(schedule_, std::ranges::greater{}, &TimerHandle::first);
     }
 
     void cancel_handle(Handle& handle) {
-        cancelled_.insert(&handle);
+        cancelled_.insert(handle.get_handle_id());
     }
 
     void call_soon(Handle& callback) {
         callback.set_state(PromiseState::PENDING);
-        ready_.emplace(&callback);
+        ready_.push({callback.get_handle_id(), &callback});
     }
 
     template<concepts::Future Fut>
@@ -90,14 +101,15 @@ class EventLoop: private NonCopyable {
 
 private:
     MSDuration start_time_;
-    std::queue<Handle*> ready_;
-    std::set<Handle*> cancelled_;
+    std::queue<HandleInfo> ready_;
+    std::unordered_set<HandleId> cancelled_;
     Selector selector_;
-    using TimerHandle = std::pair<MSDuration, Handle*>;
+    using TimerHandle = std::pair<MSDuration, HandleInfo>;
     std::vector<TimerHandle> schedule_; // min time heap
+    static HandleId handle_alloc_id_;
 };
 
 EventLoop& get_event_loop();
 ASYNCIO_NS_END
 
-#endif // ASYNCIO_EVENT_LOOP_H
+#endif // ASYNCIO_EVENT_LOOP_H

include/asyncio/handle.h

@@ -15,6 +15,9 @@ enum class PromiseState: uint8_t {
     PENDING,
 };
 
+// for cancelled
+using HandleId = uint64_t;
+
 struct Handle { // type erase for EventLoop
     virtual void run() = 0;
     std::string frame_name() const {
@@ -24,12 +27,18 @@ struct Handle { // type erase for EventLoop
     }
     virtual void dump_backtrace(size_t depth = 0) const {};
     virtual void set_state(PromiseState state) {}
+    HandleId get_handle_id() { return handle_id_; }
+    Handle() noexcept;
     virtual ~Handle() = default;
+
 private:
     virtual const std::source_location& get_frame_info() const {
         static const std::source_location frame_info = std::source_location::current();
         return frame_info;
     }
+
+private:
+    HandleId handle_id_;
 };
 
 ASYNCIO_NS_END

include/asyncio/task.h

@@ -148,4 +148,4 @@ struct Task: private NonCopyable {
 };
 
 ASYNCIO_NS_END
-#endif // ASYNCIO_TASK_H
+#endif // ASYNCIO_TASK_H

src/event_loop.cpp

@@ -23,8 +23,8 @@ void EventLoop::run_once() {
     std::optional<MSDuration> timeout;
     // Remove delayed calls that were cancelled from head of queue.
     while (! schedule_.empty()) {
-        auto&& [when, handle] = schedule_[0];
-        if (auto iter = cancelled_.find(handle); iter != cancelled_.end()) {
+        auto&& [when, handle_info] = schedule_[0];
+        if (auto iter = cancelled_.find(handle_info.id); iter != cancelled_.end()) {
             ranges::pop_heap(schedule_,std::ranges::greater{}, &TimerHandle::first);
             schedule_.pop_back();
             cancelled_.erase(iter);
@@ -43,27 +43,33 @@ void EventLoop::run_once() {
     auto event_lists = selector_.select(timeout.has_value() ? timeout->count() : -1);
     for (auto&& event: event_lists) {
         Handle* continuation_ = reinterpret_cast<Handle*>(event.data);
-        ready_.emplace(continuation_);
+        ready_.push({continuation_->get_handle_id(), continuation_});
     }
 
     auto end_time = time();
     while (! schedule_.empty()) {
-        auto&& [when, handle] = schedule_[0];
+        auto&& [when, handle_info] = schedule_[0];
         if (when >= end_time) break;
-        ready_.emplace(handle);
+        ready_.push(handle_info);
         ranges::pop_heap(schedule_,std::ranges::greater{}, &TimerHandle::first);
         schedule_.pop_back();
     }
 
     for (size_t ntodo = ready_.size(), i = 0; i < ntodo ; ++i ) {
-        auto handle = ready_.front();
+        auto [handle_id, handle] = ready_.front();
         ready_.pop();
-        if (auto iter = cancelled_.find(handle); iter != cancelled_.end()) {
+        if (auto iter = cancelled_.find(handle_id); iter != cancelled_.end()) {
             cancelled_.erase(iter);
         } else {
             handle->run();
         }
     }
 }
 
-ASYNCIO_NS_END
+HandleId EventLoop::handle_alloc_id_ = 0;
+
+Handle::Handle() noexcept {
+    auto& loop = get_event_loop();
+    handle_id_ = loop.allocate_handle_id();
+}
+ASYNCIO_NS_END