Add event loop with uv

1 files changed, 94 insertions, 0 deletions

diff --git a/src/AsyncEventLoop.cpp b/src/AsyncEventLoop.cpp
new file mode 100644
index 0000000..360a45e
--- /dev/null
+++ b/src/AsyncEventLoop.cpp
@@ -0,0 +1,94 @@
+#include <QtCore>
+#include <functional>
+#include <mutex>
+#include <thread>
+#include <uv.h>
+
+#include "AsyncEventLoop.hpp"
+
+AsyncEventLoop::AsyncEventLoop() {
+  // UV Loop
+  loop = (uv_loop_t *)malloc(sizeof(uv_loop_t));
+  uv_loop_init(loop);
+
+  uv_async_init(loop, &asyncHandle, AsyncEventLoop::asyncHandleCallback);
+  asyncHandle.data = this;
+
+  loopThread = std::thread(&AsyncEventLoop::runLoop, this);
+
+  // Wait for thread to start
+  while (!isLoopRunning)
+    std::this_thread::sleep_for(std::chrono::milliseconds(50));
+}
+
+void AsyncEventLoop::processTasks() {
+  std::queue<std::function<void()>> tasks;
+
+  {
+    std::lock_guard<std::mutex> lock(tasksQueueMutex);
+    tasksQueue.swap(tasks);
+  }
+
+  while (!tasks.empty()) {
+    auto task = std::move(tasks.front());
+    tasks.pop();
+    task();
+  }
+}
+
+void AsyncEventLoop::runLoop() {
+  isLoopRunning = true;
+  while (isLoopRunning) {
+    int result = uv_run(loop, UV_RUN_ONCE);
+    if (result == 0)
+      std::this_thread::sleep_for(std::chrono::milliseconds(10));
+  }
+  uv_run(loop, UV_RUN_NOWAIT);
+}
+
+AsyncEventLoop::~AsyncEventLoop() {
+  if (!isLoopRunning)
+    return;
+  isLoopRunning = false;
+
+  // Clear the tasks queue
+  {
+    std::lock_guard<std::mutex> lock(tasksQueueMutex);
+    std::queue<std::function<void()>>().swap(tasksQueue);
+  }
+
+  // Wake it up. Stab it to death.
+  uv_async_send(&asyncHandle);
+  std::this_thread::sleep_for(std::chrono::milliseconds(100));
+  uv_stop(loop);
+
+  // Close all handles
+  AsyncEventLoop::closeHandle((uv_handle_t *)&asyncHandle);
+  uv_walk(loop, AsyncEventLoop::closeHandle, nullptr);
+  while (uv_run(loop, UV_RUN_ONCE) != 0)
+    ;
+  // TODO: Fix pending handler case (setTimeout(100) wait(20) close() -> error)
+
+  qDebug() << "join start";
+  if (loopThread.joinable())
+    loopThread.join();
+  qDebug() << "join done";
+
+  while (uv_loop_close(loop) == UV_EBUSY) {
+    uv_walk(loop, AsyncEventLoop::closeHandle, nullptr);
+    uv_run(loop, UV_RUN_NOWAIT);
+  }
+  free(loop);
+  loop = nullptr;
+}
+
+void AsyncEventLoop::asyncHandleCallback(uv_async_t *handle) {
+  auto *runtime = static_cast<AsyncEventLoop *>(handle->data);
+  runtime->processTasks();
+}
+
+void AsyncEventLoop::closeHandle(uv_handle_t *handle, void *arg) {
+  if (!uv_is_closing(handle)) {
+    uv_close(handle, [](uv_handle_t *h) { h->data = nullptr; });
+  }
+}