Remove pthread dependency

src/ftxui/component/task_runner.cpp

@@ -0,0 +1,77 @@
+// Copyright 2024 Arthur Sonzogni. All rights reserved.
+// Use of this source code is governed by the MIT license that can be found in
+// the LICENSE file.
+#include "ftxui/component/task_runner.hpp"
+
+#include <cassert>
+#include <thread>
+
+namespace ftxui::task {
+
+static thread_local TaskRunner* current_task_runner = nullptr;  // NOLINT
+
+TaskRunner::TaskRunner() {
+  assert(!previous_task_runner_);
+  previous_task_runner_ = current_task_runner;
+  current_task_runner = this;
+}
+
+TaskRunner::~TaskRunner() {
+  current_task_runner = previous_task_runner_;
+}
+
+
+// static
+auto TaskRunner::Current() -> TaskRunner* {
+  assert(current_task_runner);
+  return current_task_runner;
+}
+
+auto TaskRunner::PostTask(Task task) -> void {
+  queue_.PostTask(PendingTask{std::move(task)});
+}
+
+auto TaskRunner::PostDelayedTask(Task task,
+                                 std::chrono::steady_clock::duration duration)
+    -> void {
+  queue_.PostTask(PendingTask{std::move(task), duration});
+}
+
+/// Runs the tasks in the queue.
+auto TaskRunner::RunUntilIdle()
+    -> std::optional<std::chrono::steady_clock::duration> {
+  while (true) {
+    auto maybe_task = queue_.Get();
+    if (std::holds_alternative<std::monostate>(maybe_task)) {
+      // No more tasks to execute, exit the loop.
+      return std::nullopt;
+    }
+
+    if (std::holds_alternative<Task>(maybe_task)) {
+      executed_tasks_++;
+      std::get<Task>(maybe_task)();
+      continue;
+    }
+
+    if (std::holds_alternative<std::chrono::steady_clock::duration>(
+            maybe_task)) {
+      return std::get<std::chrono::steady_clock::duration>(maybe_task);
+    }
+  }
+}
+
+auto TaskRunner::Run() -> void {
+  while (true) {
+    auto duration = RunUntilIdle();
+    if (!duration) {
+      // No more tasks to execute, exit the loop.
+      return;
+    }
+
+    // Sleep for the duration until the next task can be executed.
+    std::this_thread::sleep_for(duration.value());
+  }
+}
+
+} // namespace ftxui::task
+