custom folly executor for running coroutines on GLib main context

CMakeLists.txt

@@ -39,7 +39,7 @@ add_executable(autocat_gnome main.cpp
         services/Settings.h
         gui/TitleBar.cpp
         gui/TitleBar.h
-        coro/Coro.h)
+        coro/Coro.h coro/GLibMainContextExecutor.cpp coro/GLibMainContextExecutor.h)
 
 target_link_libraries(autocat_gnome ${GTKMM_LIBRARIES}
                                     ${GLIBMM_LIBRARIES}

coro/GLibMainContextExecutor.cpp

@@ -0,0 +1,32 @@
+//
+// Created by selim on 09.05.2022.
+//
+
+#include "GLibMainContextExecutor.h"
+#include <glibmm.h>
+
+int callback(void* data) {
+    auto executor = reinterpret_cast<GLibMainContextExecutor*>(data);
+    executor->runFront();
+    return G_SOURCE_REMOVE;
+}
+
+void GLibMainContextExecutor::add(folly::Func func) {
+    std::lock_guard<std::mutex> lock(_mutex);
+    _tasks.push(std::move(func));
+    g_idle_add_full(G_PRIORITY_DEFAULT_IDLE, callback, this, nullptr);
+}
+
+void GLibMainContextExecutor::runFront() {
+    std::lock_guard<std::mutex> lock(_mutex);
+    if(!_tasks.empty()) {
+        auto task = std::move(_tasks.front());
+        _tasks.pop();
+        task();
+    }
+}
+
+folly::Executor::KeepAlive<GLibMainContextExecutor> GLibMainContextExecutor::instance() {
+    static GLibMainContextExecutor instance;
+    return folly::getKeepAliveToken(instance);
+}

coro/GLibMainContextExecutor.h

@@ -0,0 +1,25 @@
+//
+// Created by selim on 09.05.2022.
+//
+
+#ifndef AUTOCAT_GNOME_GLIBMAINCONTEXTEXECUTOR_H
+#define AUTOCAT_GNOME_GLIBMAINCONTEXTEXECUTOR_H
+
+#include <folly/Executor.h>
+#include <queue>
+#include <mutex>
+
+class GLibMainContextExecutor: public folly::Executor {
+private:
+    std::queue<folly::Func> _tasks;
+    std::mutex _mutex;
+
+public:
+    static folly::Executor::KeepAlive<GLibMainContextExecutor> instance();
+    ~GLibMainContextExecutor() override = default;
+    void add(folly::Func func) override;
+    void runFront();
+};
+
+
+#endif //AUTOCAT_GNOME_GLIBMAINCONTEXTEXECUTOR_H

gui/LoginWindow.cpp

@@ -5,6 +5,7 @@
 #include "LoginWindow.h"
 #include "MainWindow.h"
 #include "../services/Api.h"
+#include "../coro/GLibMainContextExecutor.h"
 
 #include <gtkmm/application.h>
 #include <gtkmm/box.h>
@@ -50,7 +51,7 @@ void LoginWindow::loginClicked() {
     _spinner.start();
 
     try {
-        User user = co_await Api::login(email, password).scheduleOn(folly::getGlobalIOExecutor());
+        User user = co_await Api::login(email, password).scheduleOn(GLibMainContextExecutor::instance());
         auto app = this->get_application();
         auto mainWindow = new MainWindow();
         mainWindow->show();