Boost::Asio Asynchronous Mutex Implementation about asio

[ArielSilver]

#include <iostream>
#include <boost/asio.hpp>
#include <boost/thread.hpp>
class AsyncMutex {
public:
 AsyncMutex(boost::asio::io_context& ioContext)
 : strand_(ioContext), locked_(false) {}
 template <typename Handler>
 void lock(Handler&& handler) {
 strand_.post([this, handler = std::move(handler)]() mutable {
 if (!locked_) {
 locked_ = true;
 handler(boost::system::error_code());
 } else {
 waitingTasks_.emplace_back(std::move(handler));
 }
 });
 }
 void unlock() {
 strand_.post([this]() {
 if (waitingTasks_.empty()) {
 locked_ = false;
 } else {
 auto handler = std::move(waitingTasks_.front());
 waitingTasks_.pop_front();
 handler(boost::system::error_code());
 }
 });
 }
private:
 boost::asio::io_context::strand strand_;
 bool locked_;
 std::list<std::function<void(boost::system::error_code)>> 
waitingTasks_;
};
int main() {
 boost::asio::io_context ioContext;
 AsyncMutex asyncMutex(ioContext);
 // Create the first task
 ioContext.post([&asyncMutex]() {
 asyncMutex.lock([&asyncMutex](const 
boost::system::error_code&) {
 std::cout << "Locked in thread: " << boost::this_thread::get_id() 
<< std::endl;
 // Simulate some asynchronous operation
 
boost::this_thread::sleep_for(boost::chrono::milliseconds(2000));
 std::cout << "Unlocked in thread: " << 
boost::this_thread::get_id() << std::endl;
 asyncMutex.unlock();
 });
 });
 // Create the second task
 ioContext.post([&asyncMutex]() {
 asyncMutex.lock([&asyncMutex](const 
boost::system::error_code&) {
 std::cout << "Locked in thread: " << boost::this_thread::get_id() 
<< std::endl;
 // Simulate some asynchronous operation
 
boost::this_thread::sleep_for(boost::chrono::milliseconds(3000));
 std::cout << "Unlocked in thread: " << 
boost::this_thread::get_id() << std::endl;
 asyncMutex.unlock();
 });
 });
 // Run the ioContext to start executing the tasks
 ioContext.run();
 return 0;
}

Explanation:
We define the AsyncMutex class that provides an
asynchronous mutex implementation using
Boost.Asio.
The lock method takes a handler as a parameter
and posts a task to the strand_ of the
ioContext. If the mutex is not locked, it sets the
locked_ flag to true and invokes the handler
immediately. Otherwise, it adds the handler to the
waitingTasks_ list for execution when the
mutex is unlocked.
The unlock method posts a task to the strand_
of the ioContext that checks if there are any
waiting tasks in the waitingTasks_ list. If there
are, it removes the first task from the list and
invokes its handler. If there are no waiting tasks, it
sets the locked_ flag to false.
In the main function, we create an instance of
AsyncMutex and an ioContext.
We create two tasks by using the
ioContext.post function and capturing the
AsyncMutex instance by reference.
Each task calls the lock method on the
asyncMutex and provides a lambda function as
the handler

[klemens-morgenstern]

This compiles?

Either way, maybe take a look at sam.

I don't think that library will end up boost however, but feel free to copy & paste.