feat: add clear_tasks()

include/thread_pool/thread_pool.h

@@ -241,6 +241,25 @@ namespace dp {
             }
         }
 
+        /**
+         * @brief Makes best-case attempt to clear all tasks from the thread_pool
+         */
+        void clear_tasks() {
+            // Note that this does not guarantee that all tasks will be cleared, as currently
+            // running tasks could add additional tasks. Also a thread could steal a task from
+            // another in the middle of this
+
+            size_t removed_task_count = 0;
+            for (auto &task_list : tasks_)
+                removed_task_count += task_list.tasks.clear();
+            in_flight_tasks_.fetch_sub(removed_task_count, std::memory_order_release);
+            unassigned_tasks_.fetch_sub(removed_task_count, std::memory_order_release);
+
+            // We signal at the end (instead of in previous for loop), to reduce the chance of a
+            // thread stealing a task from another.
+            for (auto &task_list : tasks_) task_list.signal.release();
+        }
+
       private:
         template <typename Function>
         void enqueue_task(Function &&f) {

include/thread_pool/thread_safe_queue.h

@@ -44,6 +44,14 @@ namespace dp {
             return data_.empty();
         }
 
+        size_type clear() {
+            std::scoped_lock lock(mutex_);
+            auto size = data_.size();
+            data_.clear();
+
+            return size;
+        }
+
         [[nodiscard]] std::optional<T> pop_front() {
             std::scoped_lock lock(mutex_);
             if (data_.empty()) return std::nullopt;