// -*- mode: c++; c-basic-offset:4 -*-

// This file is part of libdap, A C++ implementation of the OPeNDAP Data

// Access Protocol.

// Copyright (c) 2015 OPeNDAP, Inc.

// Author: James Gallagher <jgallagher@opendap.org>

//

// This library is free software; you can redistribute it and/or

// modify it under the terms of the GNU Lesser General Public

// License as published by the Free Software Foundation; either

// version 2.1 of the License, or (at your option) any later version.

//

// This library is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

// Lesser General Public License for more details.

//

// You should have received a copy of the GNU Lesser General Public

// License along with this library; if not, write to the Free Software

// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

//

// You can contact OPeNDAP, Inc. at PO Box 112, Saunderstown, RI. 02874-0112.

/*

 * MarshallerThread.h

 *

 *  Created on: Aug 27, 2015

 *      Author: jimg

 */

#ifndef MARSHALLERTHREAD_H_

#define MARSHALLERTHREAD_H_

#include <pthread.h>

#include <iostream>

#include <ostream>

#include <string>

namespace libdap {

/**

 * RAII for the MarshallerThread mutex and condition variable. Used by the

 * Main thread. The constructor locks the mutex and then, if the count of

 * child threads is not zero, blocks on the associated condition variable.

 * When signaled by the child thread using the condition variable (the child

 * thread count should then be zero), the mutex is (re)locked and the ctor

 * returns. The destructor unlocks the mutex.

 */

class Locker {

public:

    Locker(pthread_mutex_t &lock, pthread_cond_t &cond, int &count);

    virtual ~Locker();

private:

    pthread_mutex_t& m_mutex;

    Locker();

    Locker(const Locker &rhs;;

};

/**

 * Synchronization for the child thread in the multi-threaded version of

 * the DAP2 and DAP4 (when it gets implement) 'Marshaller' class used to

 * send data. The class declared below (MarshallerThread) manages the

 * child thread.

 *

 * The ctor of this class simply

 * locks the mutex; the dtor clears the child thread count, signals that

 * count has changed and unlocks the mutex.

 */

class ChildLocker {

public:

    ChildLocker(pthread_mutex_t &lock, pthread_cond_t &cond, int &count);

    virtual ~ChildLocker();

private:

    pthread_mutex_t& m_mutex;

    pthread_cond_t& m_cond;

    int& m_count;

    ChildLocker();

    ChildLocker(const Locker &rhs;;

};

/**

 * Implement a multi-threaded data transmission sub-system for libdap.

 * This class makes it fairly painless to send data using a child thread

 * so that the main thread can be used to read the next chunk of data

 * while whatever has been read to this point is sent over the wire.

 *

 * This code is used by XDRStreamMarshaller and (soon) D4StreamMarshaller.

 */

class MarshallerThread {

private:

    pthread_t d_thread;

    pthread_attr_t d_thread_attr;

    pthread_mutex_t d_out_mutex;

    pthread_cond_t d_out_cond;

    int d_child_thread_count;   // 0 or 1

    std::string d_thread_error; // non-null indicates an error

#if 0

    static bool print_time; // false by default

#endif

    /**

     * Used to pass information into the static methods that run the

     * simple stream writer threads. This can pass both an ostream or

     * a file descriptor. If a fd is passed, the ostream reference is

     * set to stderr (i.e., std::cerr).

     */

    struct write_args {

        pthread_mutex_t &d_mutex;

        pthread_cond_t &d_cond;

        int &d_count;

        std::string &d_error;

        std::ostream &d_out;     // The output stream protected by the mutex, ...

        int d_out_file;       // file descriptor; if not -1, use this.

        char *d_buf;        // The data to write to the stream

        int d_num;          // The size of d_buf

        /**

         * Build args for an ostream. The file descriptor is set to -1

         */

        write_args(pthread_mutex_t &m, pthread_cond_t &c, int &count, std::string &e, std::ostream &s, char *vals, int num) :

            d_mutex(m), d_cond(c), d_count(count), d_error(e), d_out(s), d_out_file(-1), d_buf(vals), d_num(num)

        {

        }

        /**

         * Build args for a file descriptr. The ostream is set to cerr (because it is

         * a reference and has to be initialized to something).

         */

        write_args(pthread_mutex_t &m, pthread_cond_t &c, int &count, std::string &e, int fd, char *vals, int num) :

            d_mutex(m), d_cond(c), d_count(count), d_error(e), d_out(std::cerr), d_out_file(fd), d_buf(vals), d_num(num)

        {

        }

   };

public:

    MarshallerThread();

    virtual ~MarshallerThread();

    pthread_mutex_t &get_mutex() { return d_out_mutex; }

    pthread_cond_t &get_cond() { return d_out_cond; }

    int &get_child_thread_count() { return d_child_thread_count; }

    void increment_child_thread_count() { ++d_child_thread_count; }

    void start_thread(void* (*thread)(void *arg), std::ostream &out, char *byte_buf, unsigned int bytes_written);

    void start_thread(void* (*thread)(void *arg), int fd, char *byte_buf, unsigned int bytes_written);

    // These are static so they will have c-linkage - required because they

    // are passed to pthread_create()

    static void *write_thread(void *arg);

    static void *write_thread_part(void *arg);

#if 0

    static void set_print_time(bool state) { print_time = state; }

    static bool get_print_time() { return print_time; }

#endif

};

}

#endif /* MARSHALLERTHREAD_H_ */