src: use unique_ptr for scheduled delayed tasks

Use std::unique_ptr for delayed tasks in the scheduled delayed tasks vector. This makes it clear that the vector has ownership of the delayed tasks and is responsible for deleting them. Use a custom deleter for the pointers because libuv needs to close the handle and then delete the data. Provide the handle when creating the pointer instead of invoking the special delete action everytime an element is removed from the vector. Backport-PR-URL: #20901 PR-URL: #17083 Reviewed-By: Anna Henningsen <[email protected]>

Author: fhinkel

src/node_platform.cc

@@ -134,26 +134,23 @@ void PerIsolatePlatformData::RunForegroundTask(std::unique_ptr<Task> task){
  task->Run();
 }
 
+voidPerIsolatePlatformData::DeleteFromScheduledTasks(DelayedTask* task){
+auto it = std::find_if(scheduled_delayed_tasks_.begin(),
+ scheduled_delayed_tasks_.end(),
+ [task](const DelayedTaskPointer& delayed) -> bool{
+return delayed.get() == task;
+ });
+CHECK_NE(it, scheduled_delayed_tasks_.end());
+ scheduled_delayed_tasks_.erase(it);
+}
+
 voidPerIsolatePlatformData::RunForegroundTask(uv_timer_t* handle){
  DelayedTask* delayed = static_cast<DelayedTask*>(handle->data);
-auto& tasklist = delayed->platform_data->scheduled_delayed_tasks_;
-auto it = std::find(tasklist.begin(), tasklist.end(), delayed);
-CHECK_NE(it, tasklist.end());
- tasklist.erase(it);
 RunForegroundTask(std::move(delayed->task));
-uv_close(reinterpret_cast<uv_handle_t*>(&delayed->timer),
- [](uv_handle_t* handle){
-deletestatic_cast<DelayedTask*>(handle->data);
- });
+ delayed->platform_data->DeleteFromScheduledTasks(delayed);
 }
 
 voidPerIsolatePlatformData::CancelPendingDelayedTasks(){
-for (auto delayed : scheduled_delayed_tasks_){
-uv_close(reinterpret_cast<uv_handle_t*>(&delayed->timer),
- [](uv_handle_t* handle){
-deletestatic_cast<DelayedTask*>(handle->data);
- });
- }
  scheduled_delayed_tasks_.clear();
 }
 
@@ -183,7 +180,14 @@ bool PerIsolatePlatformData::FlushForegroundTasksInternal(){
 // the delay is non-zero. This should not be a problem in practice.
 uv_timer_start(&delayed->timer, RunForegroundTask, delay_millis, 0);
 uv_unref(reinterpret_cast<uv_handle_t*>(&delayed->timer));
- scheduled_delayed_tasks_.push_back(delayed.release());
+
+ scheduled_delayed_tasks_.emplace_back(delayed.release(),
+ [](DelayedTask* delayed){
+uv_close(reinterpret_cast<uv_handle_t*>(&delayed->timer),
+ [](uv_handle_t* handle){
+deletestatic_cast<DelayedTask*>(handle->data);
+ });
+ });
  }
 while (std::unique_ptr<Task> task = foreground_tasks_.Pop()){
  did_work = true;

src/node_platform.h

@@ -4,6 +4,7 @@
 #include<queue>
 #include<unordered_map>
 #include<vector>
+#include<functional>
 
 #include"libplatform/libplatform.h"
 #include"node.h"
@@ -64,6 +65,8 @@ class PerIsolatePlatformData{
 voidCancelPendingDelayedTasks();
 
 private:
+voidDeleteFromScheduledTasks(DelayedTask* task);
+
 staticvoidFlushTasks(uv_async_t* handle);
 staticvoidRunForegroundTask(std::unique_ptr<v8::Task> task);
 staticvoidRunForegroundTask(uv_timer_t* timer);
@@ -74,7 +77,11 @@ class PerIsolatePlatformData{
 uv_async_t* flush_tasks_ = nullptr;
  TaskQueue<v8::Task> foreground_tasks_;
  TaskQueue<DelayedTask> foreground_delayed_tasks_;
- std::vector<DelayedTask*> scheduled_delayed_tasks_;
+
+// Use a custom deleter because libuv needs to close the handle first.
+typedef std::unique_ptr<DelayedTask, std::function<void(DelayedTask*)>>
+ DelayedTaskPointer;
+ std::vector<DelayedTaskPointer> scheduled_delayed_tasks_;
 };
 
 classNodePlatform : publicMultiIsolatePlatform{