/*
 * Copyright (c) 2015, 2021, Oracle and/or its affiliates.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2.0,
 * as published by the Free Software Foundation.
 *
 * This program is also distributed with certain software (including
 * but not limited to OpenSSL) that is licensed under separate terms,
 * as designated in a particular file or component or in included license
 * documentation.  The authors of MySQL hereby grant you an additional
 * permission to link the program and your derivative works with the
 * separately licensed software that they have included with MySQL.
 *
 * This program 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 General Public License, version 2.0, for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301  USA
 */

#ifndef _NGS_THREAD_H_
#define _NGS_THREAD_H_

#ifdef NGS_STANDALONE
# include <pthread.h>
#else
# include <my_thread.h>
# include <thr_mutex.h>
# include <thr_cond.h>
# include <mutex_lock.h>
# include "xpl_performance_schema.h"
#endif

#include <deque>
#include "ngs_common/bind.h"

namespace ngs
{
#ifdef NGS_STANDALONE
#else
  typedef my_thread_handle Thread_t;
  typedef my_thread_attr_t Thread_attr_t;
  typedef my_start_routine Start_routine_t;
#endif

  void thread_create(PSI_thread_key key, Thread_t *hread,
                     Start_routine_t func, void *arg);
  int thread_join(Thread_t *thread, void *   *ret);

  class Mutex
  {
  public:
    friend class Cond;

    Mutex(PSI_mutex_key key = PSI_NOT_INSTRUMENTED);
    ~Mutex();

    operator mysql_mutex_t*();

    void lock()
    {
      mysql_mutex_lock(&m_mutex);
    }

    bool try_lock()
    {
      return mysql_mutex_trylock(&m_mutex);
    }

    void unlock()
    {
      mysql_mutex_unlock(&m_mutex);
    }

  private:
    Mutex(const Mutex&);
    Mutex& operator=(const Mutex&);

    mysql_mutex_t m_mutex;
  };


  class RWLock
  {
  public:
    RWLock(PSI_rwlock_key key = PSI_NOT_INSTRUMENTED);
    ~RWLock();

    operator mysql_rwlock_t*() { return &m_rwlock; }

    void rlock()
    {
      mysql_rwlock_rdlock(&m_rwlock);
    }

    void wlock()
    {
      mysql_rwlock_wrlock(&m_rwlock);
    }

    bool try_wlock()
    {
      return mysql_rwlock_trywrlock(&m_rwlock) == 0;
    }

    void unlock()
    {
      mysql_rwlock_unlock(&m_rwlock);
    }

  private:
    RWLock(const RWLock&);
    RWLock& operator=(const RWLock&);

    mysql_rwlock_t m_rwlock;
  };


  class RWLock_readlock
  {
  public:
    RWLock_readlock(RWLock &lock)
    : m_lock(lock)
    {
      m_lock.rlock();
    }

    ~RWLock_readlock()
    {
      m_lock.unlock();
    }

  private:
    RWLock_readlock(const RWLock_readlock&);
    RWLock_readlock& operator=(RWLock_readlock&);
    RWLock &m_lock;
  };


  class RWLock_writelock
  {
  public:
    RWLock_writelock(RWLock &lock, bool try_ = false)
    : m_lock(lock)
    {
      if (try_)
        m_locked = m_lock.try_wlock() == 0;
      else
      {
        m_lock.wlock();
        m_locked = true;
      }
    }

    ~RWLock_writelock()
    {
      m_lock.unlock();
    }

    bool locked() const { return m_locked; }

  private:
    RWLock_writelock(const RWLock_writelock&);
    RWLock_writelock& operator=(RWLock_writelock&);
    RWLock &m_lock;
    bool m_locked;
  };


  class Cond
  {
  public:
    Cond(PSI_cond_key key = PSI_NOT_INSTRUMENTED);
    ~Cond();

    void wait(Mutex& mutex);
    int timed_wait(Mutex& mutex, unsigned long long nanoseconds);
    void signal();
    void signal(Mutex& mutex);
    void broadcast();
    void broadcast(Mutex& mutex);

  private:
    Cond(const Cond&);
    Cond& operator=(const Cond&);

    mysql_cond_t m_cond;
  };


  template<typename Container, typename Locker, typename Lock>
  class Locked_container
  {
  public:
    Locked_container(Container &container, Lock &lock)
    : m_lock(lock), m_ref(container)
    { }

    Container &operator *()
    {
      return m_ref;
    }

    Container *operator ->()
    {
      return &m_ref;
    }

    Container *container()
    {
      return &m_ref;
    }

  private:
    Locked_container(const Locked_container&);
    Locked_container& operator=(const Locked_container&);

    Locker m_lock;
    Container &m_ref;
  };


  template<typename Variable_type>
  class Sync_variable
  {
  public:
    Sync_variable(const Variable_type value)
    : m_value(value)
    {
    }

    bool is(const Variable_type value_to_check)
    {
      Mutex_lock lock(m_mutex);

      return value_to_check == m_value;
    }

    template<std::size_t NUM_OF_ELEMENTS>
    bool is(const Variable_type (&expected_value)[NUM_OF_ELEMENTS])
    {
      Mutex_lock lock(m_mutex);

      const Variable_type *begin_element = expected_value;
      const Variable_type *end_element = expected_value + NUM_OF_ELEMENTS;

      return find(begin_element, end_element, m_value);
    }

    bool exchange(const Variable_type expected_value, const Variable_type new_value)
    {
      Mutex_lock lock(m_mutex);

      bool result = false;

      if(expected_value == m_value)
      {
        m_value = new_value;

        m_cond.signal();
        result = true;
      }

      return result;
    }

    void set(const Variable_type new_value)
    {
      Mutex_lock lock(m_mutex);

      m_value = new_value;

      m_cond.signal();
    }

    Variable_type set_and_return_old(const Variable_type new_value)
    {
      Mutex_lock lock(m_mutex);

      Variable_type old_value = m_value;
      m_value = new_value;

      m_cond.signal();

      return old_value;
    }

    void wait_for(const Variable_type expected_value)
    {
      Mutex_lock lock(m_mutex);

      while (m_value != expected_value)
      {
        m_cond.wait(m_mutex);
      }
    }

    template<std::size_t NUM_OF_ELEMENTS>
    void wait_for(const Variable_type (&expected_value)[NUM_OF_ELEMENTS])
    {
      Mutex_lock lock(m_mutex);

      const Variable_type *begin_element = expected_value;
      const Variable_type *end_element = expected_value + NUM_OF_ELEMENTS;
      while (!find(begin_element, end_element, m_value)) // std::find doesn't work with (const int*)
      {
        m_cond.wait(m_mutex);
      }
    }

    template<std::size_t NUM_OF_ELEMENTS>
    void wait_for_and_set(const Variable_type (&expected_value)[NUM_OF_ELEMENTS], const Variable_type change_to)
    {
      Mutex_lock lock(m_mutex);

      const Variable_type *begin_element = expected_value;
      const Variable_type *end_element = expected_value + NUM_OF_ELEMENTS;
      while (!find(begin_element, end_element, m_value)) // std::find doesn't work with (const int*)
      {
        m_cond.wait(m_mutex);
      }

      if (change_to != m_value)
      {
        m_value = change_to;
        m_cond.signal();
      }
    }

  protected:

    bool find(const Variable_type *begin, const Variable_type *end, const Variable_type to_find)
    {
      const Variable_type *iterator = begin;
      while(iterator < end)
      {
        if (to_find == *iterator)
          return true;

        ++iterator;
      }

      return false;
    }

    Variable_type m_value;
    Mutex m_mutex;
    Cond  m_cond;
  };

  class Wait_for_signal
  {
  public:
    Wait_for_signal()
    {
      m_mutex_signal.lock();
      m_mutex_execution.lock();
    }

    ~Wait_for_signal()
    {
      m_mutex_signal.unlock();
    }

    void wait()
    {
      m_mutex_execution.unlock();
      m_cond.wait(m_mutex_signal);
    }

    class Signal_when_done
    {
    public:
      typedef ngs::function<void ()> Callback;
      Signal_when_done(Wait_for_signal &signal_variable, Callback callback)
      : m_signal_variable(signal_variable), m_callback(callback)
      {
      }

      ~Signal_when_done()
      {
        m_signal_variable.signal();
      }

      void execute()
      {
        m_signal_variable.begin_execution_ready();
        m_callback();
        Callback().swap(m_callback);
        m_signal_variable.end_execution_ready();
      }

    private:
      Wait_for_signal &m_signal_variable;
      Callback m_callback;
    };
protected:
    void begin_execution_ready()
    {
      m_mutex_execution.lock();
    }

    void end_execution_ready()
    {
      m_mutex_execution.unlock();
    }


    void signal()
    {
      m_cond.signal(m_mutex_signal);
    }
  private:
    Mutex m_mutex_signal;
    Mutex m_mutex_execution;
    Cond  m_cond;
  };

}

#endif
