init

Telegram/lib_crl/crl/common/crl_common_on_main.cpp

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+// This file is part of Desktop App Toolkit,
+// a set of libraries for developing nice desktop applications.
+//
+// For license and copyright information please follow this link:
+// https://github.com/desktop-app/legal/blob/master/LEGAL
+//
+#include <crl/crl_on_main.h>
+
+#ifdef CRL_USE_COMMON_QUEUE
+
+#include <exception>
+
+namespace {
+
+crl::queue *Queue/* = nullptr*/;
+std::atomic<int> Counter/* = 0*/;
+crl::details::main_queue_pointer Lifetime;
+
+} // namespace
+
+namespace crl::details {
+
+void main_queue_pointer::grab() {
+	auto counter = Counter.load(std::memory_order_acquire);
+	while (true) {
+		if (!counter) {
+			return;
+		} else if (Counter.compare_exchange_weak(counter, counter + 1)) {
+			_pointer = Queue;
+			return;
+		}
+	}
+}
+
+void main_queue_pointer::ungrab() {
+	if (_pointer) {
+		if (--Counter == 0) {
+			delete _pointer;
+		}
+		_pointer = nullptr;
+	}
+}
+
+void main_queue_pointer::create(main_queue_processor processor) {
+	if (Counter.load(std::memory_order_acquire) != 0) {
+		std::terminate();
+	}
+	Queue = new queue(processor);
+	Counter.store(1, std::memory_order_release);
+	_pointer = Queue;
+}
+
+} // namespace crl::details
+
+namespace crl {
+
+void init_main_queue(main_queue_processor processor) {
+	Lifetime.create(processor);
+}
+
+} // namespace crl
+
+#endif // CRL_USE_COMMON_QUEUE