Add simple mutex

with this you can lock access to shared structures

coio.cpp

@@ -324,3 +324,28 @@ coio_active_throw()
 		throw std::logic_error("Not inside coroutine");
 	}
 }
+
+CoioMutex::CoioMutex() {
+	owner = nullptr;
+}
+
+void
+CoioMutex::lock() {
+	if (owner == nullptr) {
+		owner = coio_current;
+	} else {
+		waiting.push_back(coio_current);
+		coio_delay(-1);
+	}
+}
+
+void
+CoioMutex::unlock() {
+	if (!waiting.empty()) {
+		owner = waiting.back();
+		waiting.pop_back();
+		coio_ready(owner);
+	} else {
+		owner = nullptr;
+	}
+}

coio.h

@@ -17,6 +17,7 @@
 #define COIO_H
 
 #include <functional>
+#include <vector>
 
 typedef struct CoioTask CoioTask;
 typedef std::function<void()> coio_func;
@@ -44,4 +45,18 @@ coio_active();
 void
 coio_active_throw();
 
+class CoioMutex {
+	CoioTask* owner;
+	std::vector<CoioTask*> waiting;
+public:
+	CoioMutex();
+	~CoioMutex() = default;
+
+	CoioMutex(const CoioMutex&) = delete;
+	CoioMutex& operator=(const CoioMutex&) = delete;
+
+	void lock();
+	void unlock();
+};
+
 #endif