Initial source commit

windows/runner/run_loop.cpp

@@ -0,0 +1,66 @@
+#include "run_loop.h"
+
+#include <windows.h>
+
+#include <algorithm>
+
+RunLoop::RunLoop() {}
+
+RunLoop::~RunLoop() {}
+
+void RunLoop::Run() {
+  bool keep_running = true;
+  TimePoint next_flutter_event_time = TimePoint::clock::now();
+  while (keep_running) {
+    std::chrono::nanoseconds wait_duration =
+        std::max(std::chrono::nanoseconds(0),
+                 next_flutter_event_time - TimePoint::clock::now());
+    ::MsgWaitForMultipleObjects(
+        0, nullptr, FALSE, static_cast<DWORD>(wait_duration.count() / 1000),
+        QS_ALLINPUT);
+    bool processed_events = false;
+    MSG message;
+    // All pending Windows messages must be processed; MsgWaitForMultipleObjects
+    // won't return again for items left in the queue after PeekMessage.
+    while (::PeekMessage(&message, nullptr, 0, 0, PM_REMOVE)) {
+      processed_events = true;
+      if (message.message == WM_QUIT) {
+        keep_running = false;
+        break;
+      }
+      ::TranslateMessage(&message);
+      ::DispatchMessage(&message);
+      // Allow Flutter to process messages each time a Windows message is
+      // processed, to prevent starvation.
+      next_flutter_event_time =
+          std::min(next_flutter_event_time, ProcessFlutterMessages());
+    }
+    // If the PeekMessage loop didn't run, process Flutter messages.
+    if (!processed_events) {
+      next_flutter_event_time =
+          std::min(next_flutter_event_time, ProcessFlutterMessages());
+    }
+  }
+}
+
+void RunLoop::RegisterFlutterInstance(
+    flutter::FlutterEngine* flutter_instance) {
+  flutter_instances_.insert(flutter_instance);
+}
+
+void RunLoop::UnregisterFlutterInstance(
+    flutter::FlutterEngine* flutter_instance) {
+  flutter_instances_.erase(flutter_instance);
+}
+
+RunLoop::TimePoint RunLoop::ProcessFlutterMessages() {
+  TimePoint next_event_time = TimePoint::max();
+  for (auto instance : flutter_instances_) {
+    std::chrono::nanoseconds wait_duration = instance->ProcessMessages();
+    if (wait_duration != std::chrono::nanoseconds::max()) {
+      next_event_time =
+          std::min(next_event_time, TimePoint::clock::now() + wait_duration);
+    }
+  }
+  return next_event_time;
+}