// Copyright (C) 2011-2021 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

#include <config.h>
#include <asiolink/asio_wrapper.h>
#include <asiolink/io_service.h>

#include <unistd.h>             // for some IPC/network system calls
#include <netinet/in.h>
#include <boost/shared_ptr.hpp>
#include <sys/socket.h>

namespace isc {
namespace asiolink {

namespace {
// A trivial wrapper for std::function.  SunStudio doesn't seem to be capable
// of handling a std::function object if directly passed to
// io_service::post().
class CallbackWrapper {
public:

    /// \brief Constructor
    CallbackWrapper(const std::function<void()>& callback) :
        callback_(callback) {}

    /// \brief Function operator
    void operator()() {
        callback_();
    }

private:

    /// \brief The callback function
    std::function<void()> callback_;
};
}

class IOServiceImpl {
private:
    IOServiceImpl(const IOService& source);
    IOServiceImpl& operator=(const IOService& source);
public:
    /// \brief The constructor
    IOServiceImpl() :
        io_service_(),
        work_(new boost::asio::io_service::work(io_service_)) {
    };

    /// \brief The destructor.
    ~IOServiceImpl() {};
    //@}

    /// \brief Start the underlying event loop.
    ///
    /// This method does not return control to the caller until
    /// the \c stop() method is called via some handler.
    void run() {
        io_service_.run();
    };

    /// \brief Run the underlying event loop for a single event.
    ///
    /// This method return control to the caller as soon as the
    /// first handler has completed.  (If no handlers are ready when
    /// it is run, it will block until one is.)
    void run_one() {
        io_service_.run_one();
    };

    /// \brief Run the underlying event loop for a ready events.
    ///
    /// This method executes handlers for all ready events and returns.
    /// It will return immediately if there are no ready events.
    void poll() {
        io_service_.poll();
    };

    /// \brief Stop the underlying event loop.
    ///
    /// This will return the control to the caller of the \c run() method.
    void stop() {
        io_service_.stop();
    }

    /// \brief Indicates if the IOService has been stopped.
    ///
    /// \return true if the IOService has been stopped, false otherwise.
    bool stopped() const {
        return (io_service_.stopped());
    }

    /// \brief Restarts the IOService in preparation for a subsequent \c run() invocation.
    void restart() {
        io_service_.reset();
    }

    /// \brief Removes IO service work object to let it finish running
    /// when all handlers have been invoked.
    void stopWork() {
        work_.reset();
    }

    /// \brief Return the native \c io_service object used in this wrapper.
    ///
    /// This is a short term work around to support other Kea modules
    /// that share the same \c io_service with the authoritative server.
    /// It will eventually be removed once the wrapper interface is
    /// generalized.
    boost::asio::io_service& get_io_service() {
        return (io_service_);
    }

    /// \brief Post a callback on the IO service
    ///
    /// \param callback The callback to be run on the IO service.
    void post(const std::function<void ()>& callback) {
        const CallbackWrapper wrapper(callback);
        io_service_.post(wrapper);
    }

private:
    boost::asio::io_service io_service_;
    boost::shared_ptr<boost::asio::io_service::work> work_;
};

IOService::IOService() : io_impl_(new IOServiceImpl()) {
}

IOService::~IOService() {
}

void
IOService::run() {
    io_impl_->run();
}

void
IOService::run_one() {
    io_impl_->run_one();
}

void
IOService::poll() {
    io_impl_->poll();
}

void
IOService::stop() {
    io_impl_->stop();
}

bool
IOService::stopped() const {
    return (io_impl_->stopped());
}

void
IOService::restart() {
    io_impl_->restart();
}

void
IOService::stopWork() {
    io_impl_->stopWork();
}

boost::asio::io_service&
IOService::get_io_service() {
    return (io_impl_->get_io_service());
}

void
IOService::post(const std::function<void ()>& callback) {
    return (io_impl_->post(callback));
}

} // namespace asiolink
} // namespace isc