[general] moving ios and android project under ./platform folder

platform/qt/src/async_task.cpp

@@ -0,0 +1,42 @@
+#include "async_task_impl.hpp"
+
+#include <mbgl/util/async_task.hpp>
+#include <mbgl/util/run_loop.hpp>
+
+#include <cassert>
+
+namespace mbgl {
+namespace util {
+
+AsyncTask::Impl::Impl(std::function<void()>&& fn)
+    : runLoop(RunLoop::Get()),
+      task(std::move(fn)) {
+    connect(this, SIGNAL(send(void)), this, SLOT(runTask(void)), Qt::QueuedConnection);
+}
+
+void AsyncTask::Impl::maySend() {
+    if (!queued.test_and_set()) {
+        emit send();
+    }
+}
+
+void AsyncTask::Impl::runTask() {
+    assert(runLoop == RunLoop::Get());
+
+    queued.clear();
+    task();
+}
+
+AsyncTask::AsyncTask(std::function<void()>&& fn)
+    : impl(std::make_unique<Impl>(std::move(fn))) {
+}
+
+AsyncTask::~AsyncTask() {
+}
+
+void AsyncTask::send() {
+    impl->maySend();
+}
+
+}
+}