feat update

3party/asyncplusplus/examples/gtk_scheduler.cpp

@@ -0,0 +1,98 @@
+// Copyright (c) 2015 Amanieu d'Antras
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+#include <async++.h>
+#include <gtk/gtk.h>
+#include <iostream>
+#include <chrono>
+#include <string>
+
+// Scheduler implementation
+class gtk_scheduler_impl {
+	// Get the task from the void* and execute it in the UI thread
+	static gboolean callback(void* p)
+	{
+		async::task_run_handle::from_void_ptr(p).run();
+		return FALSE;
+	}
+
+public:
+	// Convert a task to void* and send it to the gtk main loop
+	void schedule(async::task_run_handle t)
+	{
+		g_idle_add(callback, t.to_void_ptr());
+	}
+};
+
+// Scheduler to run a task in the gtk main loop
+gtk_scheduler_impl& gtk_scheduler()
+{
+	static gtk_scheduler_impl sched;
+	return sched;
+}
+
+// In order to ensure the UI is always responsive, you can disallow blocking
+// calls in the UI thread. Note that the wait handler isn't called when the
+// result of a task is already available, so you can still call .get() on a
+// completed task. This is completely optional and can be omitted if you don't
+// need it.
+void gtk_wait_handler(async::task_wait_handle)
+{
+	std::cerr << "Error: Blocking wait in UI thread" << std::endl;
+	std::abort();
+}
+
+// Thread which increments the label value every ms
+void label_update_thread(GtkLabel *label)
+{
+	int counter = 0;
+	while (true) {
+		// Sleep for 1ms
+		std::this_thread::sleep_for(std::chrono::milliseconds(1));
+		counter++;
+
+		// Update the label contents in the UI thread
+		async::spawn(gtk_scheduler(), [label, counter] {
+			gtk_label_set_text(label, std::to_string(counter).c_str());
+		});
+	}
+}
+
+int main(int argc, char *argv[])
+{
+	// Initialize GTK
+	gtk_init(&argc, &argv);
+
+	// Set wait handler on GTK thread to disallow waiting for tasks
+	async::set_thread_wait_handler(gtk_wait_handler);
+
+	// Create a window with a label
+	GtkWidget *window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
+	g_signal_connect(window, "destroy", G_CALLBACK(gtk_main_quit), NULL);
+	GtkLabel *label = GTK_LABEL(gtk_label_new("-"));
+	gtk_container_add(GTK_CONTAINER(window), GTK_WIDGET(label));
+	gtk_widget_show_all(window);
+
+	// Start a secondary thread to update the label
+	std::thread(label_update_thread, label).detach();
+
+	// Go to GTK main loop
+	gtk_main();
+}