/* Copyright (c) 2015, 2020, Oracle and/or its affiliates. All rights reserved.

   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,
   51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA */

#include "my_global.h"
#include "log.h"
#include "rpl_channel_service_interface.h"
#include "rpl_slave.h"
#include "rpl_info_factory.h"
#include "rpl_mi.h"
#include "rpl_msr.h"         /* Multisource replication */
#include "rpl_rli.h"
#include "rpl_rli_pdb.h"
#include "mysqld_thd_manager.h" // Global_THD_manager
#include "sql_parse.h"          // Find_thd_with_id

/**
  Auxiliary function to stop all the running channel threads according to the
  given mask.

  @note: The caller shall possess channel_map lock before calling this function,
         and unlock after returning from this function.

  @param mi                   The pointer to Master_info instance
  @param threads_to_stop      The types of threads to be stopped
  @param timeout              The expected time in which the thread should stop

  @return the operation status
    @retval 0      OK
    @retval !=0    Error
*/
int channel_stop(Master_info *mi,
                 int threads_to_stop,
                 long timeout);


int initialize_channel_service_interface()
{
  DBUG_ENTER("initialize_channel_service_interface");

  //master info and relay log repositories must be TABLE
  if (opt_mi_repository_id != INFO_REPOSITORY_TABLE ||
      opt_rli_repository_id != INFO_REPOSITORY_TABLE)
  {
    sql_print_error("For the creation of replication channels the master info"
                    " and relay log info repositories must be set to TABLE");
    DBUG_RETURN(1);
  }

  //server id must be different from 0
  if (server_id == 0)
  {
    sql_print_error("For the creation of replication channels the server id"
                    " must be different from 0");
    DBUG_RETURN(1);
  }

  DBUG_RETURN(0);
}

#ifdef HAVE_REPLICATION

void set_mi_settings(Master_info *mi, Channel_creation_info* channel_info)
{
  mysql_mutex_lock(&mi->data_lock);

  mi->rli->set_thd_tx_priority(channel_info->thd_tx_priority);

  mi->rli->set_ignore_write_set_memory_limit(
      channel_info->m_ignore_write_set_memory_limit);
  mi->rli->set_allow_drop_write_set(channel_info->m_allow_drop_write_set);

  mi->rli->replicate_same_server_id=
    (channel_info->replicate_same_server_id == RPL_SERVICE_SERVER_DEFAULT) ?
     replicate_same_server_id : channel_info->replicate_same_server_id;

  mi->rli->opt_slave_parallel_workers=
    (channel_info->channel_mts_parallel_workers == RPL_SERVICE_SERVER_DEFAULT) ?
    opt_mts_slave_parallel_workers : channel_info->channel_mts_parallel_workers;

  if (channel_info->channel_mts_parallel_type == RPL_SERVICE_SERVER_DEFAULT)
  {
    if (mts_parallel_option == MTS_PARALLEL_TYPE_DB_NAME)
      mi->rli->channel_mts_submode = MTS_PARALLEL_TYPE_DB_NAME;
    else
      mi->rli->channel_mts_submode = MTS_PARALLEL_TYPE_LOGICAL_CLOCK;
  }
  else
  {
   if (channel_info->channel_mts_parallel_type == CHANNEL_MTS_PARALLEL_TYPE_DB_NAME)
      mi->rli->channel_mts_submode = MTS_PARALLEL_TYPE_DB_NAME;
    else
      mi->rli->channel_mts_submode = MTS_PARALLEL_TYPE_LOGICAL_CLOCK;
  }

  mi->rli->checkpoint_group=
    (channel_info->channel_mts_checkpoint_group == RPL_SERVICE_SERVER_DEFAULT) ?
    opt_mts_checkpoint_group : channel_info->channel_mts_checkpoint_group;

  mi->set_mi_description_event(new Format_description_log_event(BINLOG_VERSION));

  mysql_mutex_unlock(&mi->data_lock);
}

bool init_thread_context()
{
  return my_thread_init();
}

void clean_thread_context()
{
  my_thread_end();
}

THD *create_surrogate_thread()
{
  THD *thd= NULL;
  thd= new THD;
  thd->thread_stack= (char*) &thd;
  thd->store_globals();
  thd->security_context()->skip_grants();

  return(thd);
}

void delete_surrogate_thread(THD *thd)
{
  thd->release_resources();
  delete thd;
  my_thread_set_THR_THD(NULL);
}

void
initialize_channel_creation_info(Channel_creation_info* channel_info)
{
  channel_info->type= SLAVE_REPLICATION_CHANNEL;
  channel_info->hostname= 0;
  channel_info->port= 0;
  channel_info->user= 0;
  channel_info->password= 0;
  channel_info->ssl_info= 0;
  channel_info->auto_position= RPL_SERVICE_SERVER_DEFAULT;
  channel_info->channel_mts_parallel_type= RPL_SERVICE_SERVER_DEFAULT;
  channel_info->channel_mts_parallel_workers= RPL_SERVICE_SERVER_DEFAULT;
  channel_info->channel_mts_checkpoint_group= RPL_SERVICE_SERVER_DEFAULT;
  channel_info->replicate_same_server_id= RPL_SERVICE_SERVER_DEFAULT;
  channel_info->thd_tx_priority= 0;
  channel_info->sql_delay= RPL_SERVICE_SERVER_DEFAULT;
  channel_info->preserve_relay_logs= false;
  channel_info->retry_count= 0;
  channel_info->connect_retry= 0;
  channel_info->m_ignore_write_set_memory_limit = false;
  channel_info->m_allow_drop_write_set = false;
}

void initialize_channel_ssl_info(Channel_ssl_info* channel_ssl_info)
{
  channel_ssl_info->use_ssl= 0;
  channel_ssl_info->ssl_ca_file_name= 0;
  channel_ssl_info->ssl_ca_directory= 0;
  channel_ssl_info->ssl_cert_file_name= 0;
  channel_ssl_info->ssl_crl_file_name= 0;
  channel_ssl_info->ssl_crl_directory= 0;
  channel_ssl_info->ssl_key= 0;
  channel_ssl_info->ssl_cipher= 0;
  channel_ssl_info->tls_version= 0;
  channel_ssl_info->ssl_verify_server_cert= 0;
}

void
initialize_channel_connection_info(Channel_connection_info* channel_info)
{
  channel_info->until_condition= CHANNEL_NO_UNTIL_CONDITION;
  channel_info->gtid= 0;
  channel_info->view_id= 0;
}

void set_mi_ssl_options(LEX_MASTER_INFO* lex_mi, Channel_ssl_info* channel_ssl_info)
{

  lex_mi->ssl= (channel_ssl_info->use_ssl) ?
    LEX_MASTER_INFO::LEX_MI_ENABLE :
    LEX_MASTER_INFO::LEX_MI_DISABLE;

  if (channel_ssl_info->ssl_ca_file_name != NULL)
  {
    lex_mi->ssl_ca= channel_ssl_info->ssl_ca_file_name;
  }

  if (channel_ssl_info->ssl_ca_directory != NULL)
  {
    lex_mi->ssl_capath= channel_ssl_info->ssl_ca_directory;
  }

  if (channel_ssl_info->tls_version != NULL)
  {
    lex_mi->tls_version= channel_ssl_info->tls_version;
  }

  if (channel_ssl_info->ssl_cert_file_name != NULL)
  {
    lex_mi->ssl_cert= channel_ssl_info->ssl_cert_file_name;
  }

  if (channel_ssl_info->ssl_crl_file_name != NULL)
  {
    lex_mi->ssl_crl= channel_ssl_info->ssl_crl_file_name;
  }

  if (channel_ssl_info->ssl_crl_directory != NULL)
  {
    lex_mi->ssl_crlpath= channel_ssl_info->ssl_crl_directory;
  }

  if (channel_ssl_info->ssl_key != NULL)
  {
    lex_mi->ssl_key= channel_ssl_info->ssl_key;
  }

  if (channel_ssl_info->ssl_cipher != NULL)
  {
    lex_mi->ssl_cipher= channel_ssl_info->ssl_cipher;
  }

  lex_mi->ssl_verify_server_cert= (channel_ssl_info->ssl_verify_server_cert) ?
    LEX_MASTER_INFO::LEX_MI_ENABLE :
    LEX_MASTER_INFO::LEX_MI_DISABLE;
}

int channel_create(const char* channel,
                   Channel_creation_info* channel_info)
{
  DBUG_ENTER("channel_create");

  Master_info *mi= NULL;
  int error= 0;
  LEX_MASTER_INFO* lex_mi= NULL;

  bool thd_created= false;
  THD *thd= current_thd;

  //Don't create default channels
  if (!strcmp(channel_map.get_default_channel(), channel))
    DBUG_RETURN(RPL_CHANNEL_SERVICE_DEFAULT_CHANNEL_CREATION_ERROR);

  /* Service channels are not supposed to use sql_slave_skip_counter */
  mysql_mutex_lock(&LOCK_sql_slave_skip_counter);
  if (sql_slave_skip_counter > 0)
    error= RPL_CHANNEL_SERVICE_SLAVE_SKIP_COUNTER_ACTIVE;
  mysql_mutex_unlock(&LOCK_sql_slave_skip_counter);
  if (error)
    DBUG_RETURN(error);

  channel_map.wrlock();

  /* Get the Master_info of the channel */
  mi= channel_map.get_mi(channel);

  /* create a new channel if doesn't exist */
  if (!mi)
  {
    if ((error= add_new_channel(&mi, channel)))
        goto err;
  }

  lex_mi= new st_lex_master_info();
  lex_mi->channel= channel;
  lex_mi->host= channel_info->hostname;
  /*
    'group_replication_recovery' channel (*after recovery is done*)
    or 'group_replication_applier' channel wants to set the port number
    to '0' as there is no actual network usage on these channels.
  */
  lex_mi->port_opt= LEX_MASTER_INFO::LEX_MI_ENABLE;
  lex_mi->port= channel_info->port;
  lex_mi->user= channel_info->user;
  lex_mi->password= channel_info->password;
  lex_mi->sql_delay= channel_info->sql_delay;
  lex_mi->connect_retry= channel_info->connect_retry;
  if (channel_info->retry_count)
  {
    lex_mi->retry_count_opt= LEX_MASTER_INFO::LEX_MI_ENABLE;
    lex_mi->retry_count= channel_info->retry_count;
  }

  if (channel_info->auto_position)
  {
    lex_mi->auto_position= LEX_MASTER_INFO::LEX_MI_ENABLE;
    if ((mi && mi->is_auto_position()) ||
        channel_info->auto_position == RPL_SERVICE_SERVER_DEFAULT)
    {
      //So change master allows new configurations with a running SQL thread
      lex_mi->auto_position= LEX_MASTER_INFO::LEX_MI_UNCHANGED;
    }
  }

  if (channel_info->ssl_info != NULL)
  {
    set_mi_ssl_options(lex_mi, channel_info->ssl_info);
  }

  if (mi)
  {
    if (!thd)
    {
      thd_created= true;
      thd= create_surrogate_thread();
    }

    if ((error= change_master(thd, mi, lex_mi,
                              channel_info->preserve_relay_logs)))
    {
      goto err;
    }
  }

  set_mi_settings(mi, channel_info);

  if (channel_map.is_group_replication_channel_name(mi->get_channel()))
  {
    thd->variables.max_allowed_packet= slave_max_allowed_packet;
    thd->get_protocol_classic()->set_max_packet_size(
        slave_max_allowed_packet + MAX_LOG_EVENT_HEADER);
  }


err:
  channel_map.unlock();

  if (thd_created)
  {
    delete_surrogate_thread(thd);
  }

  delete lex_mi;

  DBUG_RETURN(error);
}

int channel_start(const char* channel,
                  Channel_connection_info* connection_info,
                  int threads_to_start,
                  int wait_for_connection)
{
  DBUG_ENTER("channel_start(channel, threads_to_start, wait_for_connection");
  int error= 0;
  int thread_mask= 0;
  LEX_MASTER_INFO lex_mi;
  ulong thread_start_id= 0;
  bool thd_created= false;
  THD* thd= current_thd;

  /* Service channels are not supposed to use sql_slave_skip_counter */
  mysql_mutex_lock(&LOCK_sql_slave_skip_counter);
  if (sql_slave_skip_counter > 0)
    error= RPL_CHANNEL_SERVICE_SLAVE_SKIP_COUNTER_ACTIVE;
  mysql_mutex_unlock(&LOCK_sql_slave_skip_counter);
  if (error)
    DBUG_RETURN(error);

  channel_map.wrlock();

  Master_info *mi= channel_map.get_mi(channel);

  if (mi == NULL)
  {
    error= RPL_CHANNEL_SERVICE_CHANNEL_DOES_NOT_EXISTS_ERROR;
    goto err;
  }

  if (threads_to_start & CHANNEL_APPLIER_THREAD)
  {
    thread_mask |= SLAVE_SQL;
  }
  if (threads_to_start & CHANNEL_RECEIVER_THREAD)
  {
    thread_mask |= SLAVE_IO;
  }

  //Nothing to be done here
  if (!thread_mask)
    goto err;

  LEX_SLAVE_CONNECTION lex_connection;
  lex_connection.reset();

  if (connection_info->until_condition != CHANNEL_NO_UNTIL_CONDITION)
  {
    switch (connection_info->until_condition)
    {
      case CHANNEL_UNTIL_APPLIER_AFTER_GTIDS:
        lex_mi.gtid_until_condition= LEX_MASTER_INFO::UNTIL_SQL_AFTER_GTIDS;
        lex_mi.gtid= connection_info->gtid;
        break;
      case CHANNEL_UNTIL_APPLIER_BEFORE_GTIDS:
        lex_mi.gtid_until_condition= LEX_MASTER_INFO::UNTIL_SQL_BEFORE_GTIDS;
        lex_mi.gtid= connection_info->gtid;
        break;
      case CHANNEL_UNTIL_APPLIER_AFTER_GAPS:
        lex_mi.until_after_gaps= true;
        break;
      case CHANNEL_UNTIL_VIEW_ID:
        DBUG_ASSERT((thread_mask & SLAVE_SQL) && connection_info->view_id);
        lex_mi.view_id= connection_info->view_id;
        break;
      default:
        DBUG_ASSERT(0);
    }
  }

  if (wait_for_connection && (thread_mask & SLAVE_IO))
    thread_start_id= mi->slave_run_id;

  if (!thd)
  {
    thd_created= true;
    thd= create_surrogate_thread();
  }

  error= start_slave(thd, &lex_connection, &lex_mi,
                     thread_mask, mi, false);

  if (wait_for_connection && (thread_mask & SLAVE_IO) && !error)
  {
    mysql_mutex_lock(&mi->run_lock);
    /*
      If the ids are still equal this means the start thread method did not
      wait for the thread to start
    */
    while (thread_start_id == mi->slave_run_id)
    {
      mysql_cond_wait(&mi->start_cond, &mi->run_lock);
    }
    mysql_mutex_unlock(&mi->run_lock);

    while (mi->slave_running != MYSQL_SLAVE_RUN_CONNECT)
    {
      //If there is such a state change then there was an error on connection
      if (mi->slave_running == MYSQL_SLAVE_NOT_RUN)
      {
        error= RPL_CHANNEL_SERVICE_RECEIVER_CONNECTION_ERROR;
        break;
      }
      my_sleep(100);
    }
  }

err:
  channel_map.unlock();

  if (thd_created)
  {
    delete_surrogate_thread(thd);
  }

  DBUG_RETURN(error);
}

int channel_stop(Master_info *mi,
                 int threads_to_stop,
                 long timeout)
{
  DBUG_ENTER("channel_stop(master_info, stop_receiver, stop_applier, timeout");

  channel_map.assert_some_lock();

  if (mi == NULL)
  {
    DBUG_RETURN(RPL_CHANNEL_SERVICE_CHANNEL_DOES_NOT_EXISTS_ERROR);
  }

  int thread_mask= 0;
  int server_thd_mask= 0;
  int error= 0;
  bool thd_init= false;

  mi->channel_wrlock();
  lock_slave_threads(mi);

  init_thread_mask(&server_thd_mask, mi, 0 /* not inverse*/);

  if ((threads_to_stop & CHANNEL_APPLIER_THREAD)
          && (server_thd_mask & SLAVE_SQL))
  {
    thread_mask |= SLAVE_SQL;
  }
  if ((threads_to_stop & CHANNEL_RECEIVER_THREAD)
          && (server_thd_mask & SLAVE_IO))
  {
    thread_mask |= SLAVE_IO;
  }

  if (thread_mask == 0)
  {
    goto end;
  }

  thd_init= init_thread_context();

  error= terminate_slave_threads(mi, thread_mask, timeout, false);

end:
  unlock_slave_threads(mi);
  mi->channel_unlock();

  if (thd_init)
  {
    clean_thread_context();
  }

  DBUG_RETURN(error);
}

int channel_stop(const char* channel,
                 int threads_to_stop,
                 long timeout)
{
  DBUG_ENTER("channel_stop(channel, stop_receiver, stop_applier, timeout");

  channel_map.rdlock();

  Master_info *mi= channel_map.get_mi(channel);

  int error= channel_stop(mi, threads_to_stop, timeout);

  channel_map.unlock();

  DBUG_RETURN(error);
}

int channel_stop_all(int threads_to_stop,
                     long timeout)
{
  DBUG_ENTER("channel_stop_all");

  int error= 0;
  Master_info *mi= 0;

  channel_map.rdlock();

  for (mi_map::iterator it= channel_map.begin(); it != channel_map.end(); it++)
  {
    mi= it->second;

    if (mi)
    {
      DBUG_PRINT("info", ("stopping channel_name: %s",
                          mi->get_channel()));

      int channel_error= channel_stop(mi, threads_to_stop, timeout);

      DBUG_EXECUTE_IF("group_replication_stop_all_channels_failure",
                      {
                        channel_error=1;
                      });

      if (channel_error &&
          channel_error != RPL_CHANNEL_SERVICE_CHANNEL_DOES_NOT_EXISTS_ERROR)
      {
        error= channel_error;
        mi->report(ERROR_LEVEL, error,
                   "Error stopping channel: %s. Got error: %d",
                   mi->get_channel(), error);
      }
    }
  }

  channel_map.unlock();
  DBUG_RETURN(error);
}

int channel_purge_queue(const char* channel, bool reset_all)
{
  DBUG_ENTER("channel_purge_queue(channel, only_purge");

  channel_map.wrlock();

  Master_info *mi= channel_map.get_mi(channel);

  if (mi == NULL)
  {
    channel_map.unlock();
    DBUG_RETURN(RPL_CHANNEL_SERVICE_CHANNEL_DOES_NOT_EXISTS_ERROR);
  }

  bool thd_init= init_thread_context();

  int error= reset_slave(current_thd, mi, reset_all);

  channel_map.unlock();

  if (thd_init)
  {
    clean_thread_context();
  }

  DBUG_RETURN(error);
}

bool channel_is_active(const char* channel, enum_channel_thread_types thd_type)
{
  int thread_mask= 0;
  DBUG_ENTER("channel_is_active(channel, thd_type");

  channel_map.rdlock();

  Master_info *mi= channel_map.get_mi(channel);

  if (mi == NULL)
  {
    channel_map.unlock();
    DBUG_RETURN(false);
  }

  init_thread_mask(&thread_mask, mi, 0 /* not inverse*/);

  channel_map.unlock();

  switch(thd_type)
  {
    case CHANNEL_NO_THD:
      DBUG_RETURN(true); //return true as the channel exists
    case CHANNEL_RECEIVER_THREAD:
      DBUG_RETURN(thread_mask & SLAVE_IO);
    case CHANNEL_APPLIER_THREAD:
      DBUG_RETURN(thread_mask & SLAVE_SQL);
    default:
      DBUG_ASSERT(0);
  }
  DBUG_RETURN(false);
}

int channel_get_thread_id(const char* channel,
                          enum_channel_thread_types thd_type,
                          unsigned long** thread_id)
{
  DBUG_ENTER("channel_get_thread_id(channel, thread_type ,*thread_id");

  int number_threads= -1;

  channel_map.rdlock();

  Master_info *mi= channel_map.get_mi(channel);

  if (mi == NULL)
  {
    channel_map.unlock();
    DBUG_RETURN(RPL_CHANNEL_SERVICE_CHANNEL_DOES_NOT_EXISTS_ERROR);
  }

  switch(thd_type)
  {
    case CHANNEL_RECEIVER_THREAD:
      mysql_mutex_lock(&mi->info_thd_lock);
      if (mi->info_thd != NULL)
      {
        *thread_id= (unsigned long*) my_malloc(PSI_NOT_INSTRUMENTED,
                                               sizeof(unsigned long),
                                               MYF(MY_WME));
        **thread_id= mi->info_thd->thread_id();
        number_threads= 1;
      }
      mysql_mutex_unlock(&mi->info_thd_lock);
      break;
    case CHANNEL_APPLIER_THREAD:
      if (mi->rli != NULL)
      {
        mysql_mutex_lock(&mi->rli->run_lock);

        if (mi->rli->slave_parallel_workers > 0)
        {
          // Parallel applier.
          size_t num_workers= mi->rli->get_worker_count();
          number_threads= 1 + num_workers;
          *thread_id=
              (unsigned long*) my_malloc(PSI_NOT_INSTRUMENTED,
                                         number_threads * sizeof(unsigned long),
                                         MYF(MY_WME));
          unsigned long *thread_id_pointer= *thread_id;

          // Set default values on thread_id array.
          for (int i= 0; i < number_threads; i++, thread_id_pointer++)
            *thread_id_pointer= -1;
          thread_id_pointer= *thread_id;

          // Coordinator thread id.
          if (mi->rli->info_thd != NULL)
          {
            mysql_mutex_lock(&mi->rli->info_thd_lock);
            *thread_id_pointer= mi->rli->info_thd->thread_id();
            mysql_mutex_unlock(&mi->rli->info_thd_lock);
            thread_id_pointer++;
          }

          // Workers thread id.
          if (mi->rli->workers_array_initialized)
          {
            for (size_t i= 0; i < num_workers; i++, thread_id_pointer++)
            {
              Slave_worker* worker= mi->rli->get_worker(i);
              if (worker != NULL)
              {
                mysql_mutex_lock(&worker->jobs_lock);
                if (worker->info_thd != NULL &&
                    worker->running_status != Slave_worker::NOT_RUNNING)
                {
                  mysql_mutex_lock(&worker->info_thd_lock);
                  *thread_id_pointer= worker->info_thd->thread_id();
                  mysql_mutex_unlock(&worker->info_thd_lock);
                }
                mysql_mutex_unlock(&worker->jobs_lock);
              }
            }
          }
        }
        else
        {
          // Sequential applier.
          if (mi->rli->info_thd != NULL)
          {
            *thread_id= (unsigned long*) my_malloc(PSI_NOT_INSTRUMENTED,
                                                     sizeof(unsigned long),
                                                     MYF(MY_WME));
            mysql_mutex_lock(&mi->rli->info_thd_lock);
            **thread_id= mi->rli->info_thd->thread_id();
            mysql_mutex_unlock(&mi->rli->info_thd_lock);
            number_threads= 1;
          }
        }
        mysql_mutex_unlock(&mi->rli->run_lock);
      }
      break;
    default:
      break;
  }

  channel_map.unlock();

  DBUG_RETURN(number_threads);
}

long long channel_get_last_delivered_gno(const char* channel, int sidno)
{
  DBUG_ENTER("channel_get_last_delivered_gno(channel, sidno)");

  channel_map.rdlock();

  Master_info *mi= channel_map.get_mi(channel);

  if (mi == NULL)
  {
    channel_map.unlock();
    DBUG_RETURN(RPL_CHANNEL_SERVICE_CHANNEL_DOES_NOT_EXISTS_ERROR);
  }

  rpl_gno last_gno= 0;

  global_sid_lock->rdlock();
  last_gno= mi->rli->get_gtid_set()->get_last_gno(sidno);
  global_sid_lock->unlock();

#if !defined(DBUG_OFF)
  const Gtid_set *retrieved_gtid_set= mi->rli->get_gtid_set();
  char *retrieved_gtid_set_string= NULL;
  global_sid_lock->wrlock();
  retrieved_gtid_set->to_string(&retrieved_gtid_set_string);
  global_sid_lock->unlock();
  DBUG_PRINT("info", ("get_last_delivered_gno retrieved_set_string: %s",
                      retrieved_gtid_set_string));
  my_free(retrieved_gtid_set_string);
#endif

  channel_map.unlock();

  DBUG_RETURN(last_gno);
}

int channel_add_executed_gtids_to_received_gtids(const char* channel)
{
  DBUG_ENTER("channel_add_executed_gtids_to_received_gtids(channel)");

  channel_map.rdlock();
  Master_info *mi= channel_map.get_mi(channel);
  if (mi == NULL)
  {
    channel_map.unlock();
    DBUG_RETURN(RPL_CHANNEL_SERVICE_CHANNEL_DOES_NOT_EXISTS_ERROR);
  }

  global_sid_lock->wrlock();

  enum_return_status return_status=
      mi->rli->add_gtid_set(gtid_state->get_executed_gtids());

  global_sid_lock->unlock();
  channel_map.unlock();

  DBUG_RETURN(return_status != RETURN_STATUS_OK);
}

int channel_queue_packet(const char* channel,
                         const char* buf,
                         unsigned long event_len)
{
  int result;
  DBUG_ENTER("channel_queue_packet(channel, event_buffer, event_len)");

  channel_map.rdlock();

  Master_info *mi= channel_map.get_mi(channel);

  if (mi == NULL)
  {
    channel_map.unlock();
    DBUG_RETURN(RPL_CHANNEL_SERVICE_CHANNEL_DOES_NOT_EXISTS_ERROR);
  }

  result= queue_event(mi, buf, event_len);

  channel_map.unlock();

  DBUG_RETURN(result);
}

int channel_wait_until_apply_queue_applied(const char* channel,
                                           double timeout)
{
  DBUG_ENTER("channel_wait_until_apply_queue_applied(channel, timeout)");

  channel_map.rdlock();

  Master_info *mi= channel_map.get_mi(channel);

  if (mi == NULL)
  {
    channel_map.unlock();
    DBUG_RETURN(RPL_CHANNEL_SERVICE_CHANNEL_DOES_NOT_EXISTS_ERROR);
  }

  mi->inc_reference();
  channel_map.unlock();

  int error = mi->rli->wait_for_gtid_set(current_thd, mi->rli->get_gtid_set(),
                                         timeout);
  mi->dec_reference();

  if (error == -1)
    DBUG_RETURN(REPLICATION_THREAD_WAIT_TIMEOUT_ERROR);
  if (error == -2)
    DBUG_RETURN(REPLICATION_THREAD_WAIT_NO_INFO_ERROR);

  DBUG_RETURN(error);
}

int channel_is_applier_waiting(const char* channel)
{
  DBUG_ENTER("channel_is_applier_waiting(channel)");
  int result= RPL_CHANNEL_SERVICE_CHANNEL_DOES_NOT_EXISTS_ERROR;

  channel_map.rdlock();

  Master_info *mi= channel_map.get_mi(channel);

  if (mi == NULL)
  {
    channel_map.unlock();
    DBUG_RETURN(result);
  }

  unsigned long* thread_ids= NULL;
  int number_appliers= channel_get_thread_id(channel,
                                             CHANNEL_APPLIER_THREAD,
                                             &thread_ids);

  if (number_appliers <= 0)
  {
    goto end;
  }

  if (number_appliers == 1)
  {
    result= channel_is_applier_thread_waiting(*thread_ids);
  }
  else if (number_appliers > 1)
  {
    int waiting= 0;

    // Check if coordinator is waiting.
    waiting += channel_is_applier_thread_waiting(thread_ids[0]);

    // Check if workers are waiting.
    for (int i= 1; i < number_appliers; i++)
      waiting += channel_is_applier_thread_waiting(thread_ids[i], true);

    // Check if all are waiting.
    if (waiting == number_appliers)
      result= 1;
    else
      result= 0;
  }

end:
  channel_map.unlock();
  my_free(thread_ids);

  DBUG_RETURN(result);
}

int channel_is_applier_thread_waiting(unsigned long thread_id, bool worker)
{
  DBUG_ENTER("channel_is_applier_thread_waiting(thread_id, worker)");
  bool result= -1;

  Find_thd_with_id find_thd_with_id(thread_id);
  THD *thd= Global_THD_manager::get_instance()->find_thd(&find_thd_with_id);
  if (thd)
  {
    result= 0;

    const char *proc_info= thd->get_proc_info();
    if (proc_info)
    {
      const char* stage_name= stage_slave_has_read_all_relay_log.m_name;
      if (worker)
        stage_name= stage_slave_waiting_event_from_coordinator.m_name;

      if (!strcmp(proc_info, stage_name))
        result= 1;
    }
    mysql_mutex_unlock(&thd->LOCK_thd_data);
  }

  DBUG_RETURN(result);
}

int channel_flush(const char* channel)
{
  DBUG_ENTER("channel_flush(channel)");

  channel_map.rdlock();

  Master_info *mi= channel_map.get_mi(channel);

  if (mi == NULL)
  {
    channel_map.unlock();
    DBUG_RETURN(RPL_CHANNEL_SERVICE_CHANNEL_DOES_NOT_EXISTS_ERROR);
  }

  bool error= flush_relay_logs(mi);

  channel_map.unlock();

  DBUG_RETURN(error ? 1 : 0);
}

int channel_get_retrieved_gtid_set(const char* channel,
                                   char** retrieved_set)
{
  DBUG_ENTER("channel_get_retrieved_gtid_set(channel,retrieved_set)");

  channel_map.rdlock();

  Master_info *mi= channel_map.get_mi(channel);

  if (mi == NULL)
  {
    channel_map.unlock();
    DBUG_RETURN(RPL_CHANNEL_SERVICE_CHANNEL_DOES_NOT_EXISTS_ERROR);
  }

  mi->inc_reference();
  channel_map.unlock();

  int error= 0;
  const Gtid_set* receiver_gtid_set= mi->rli->get_gtid_set();
  if (receiver_gtid_set->to_string(retrieved_set,
                                   true /*need_lock*/) == -1)
    error= ER_OUTOFMEMORY;

  mi->dec_reference();

  DBUG_RETURN(error);
}

bool channel_is_stopping(const char* channel,
                         enum_channel_thread_types thd_type)
{
  bool is_stopping= false;
  DBUG_ENTER("channel_is_stopping(channel, thd_type");

  channel_map.rdlock();
  Master_info *mi= channel_map.get_mi(channel);
  if (mi == NULL)
  {
    channel_map.unlock();
    DBUG_RETURN(false);
  }

  switch(thd_type)
  {
    case CHANNEL_NO_THD:
      break;
    case CHANNEL_RECEIVER_THREAD:
      is_stopping= likely(mi->is_stopping.atomic_get());
      break;
    case CHANNEL_APPLIER_THREAD:
      is_stopping= likely(mi->rli->is_stopping.atomic_get());
      break;
    default:
      DBUG_ASSERT(0);
  }

  channel_map.unlock();

  DBUG_RETURN(is_stopping);
}

bool is_partial_transaction_on_channel_relay_log(const char *channel)
{
  DBUG_ENTER("is_partial_transaction_on_channel_relay_log(channel)");
  channel_map.rdlock();
  Master_info *mi= channel_map.get_mi(channel);
  if (mi == NULL)
  {
    channel_map.unlock();
    DBUG_RETURN(false);
  }
  bool ret= mi->transaction_parser.is_inside_transaction();
  channel_map.unlock();
  DBUG_RETURN(ret);
}

bool is_any_slave_channel_running(int thread_mask)
{
  bool status;
  DBUG_ENTER("is_any_slave_channel_running");
  channel_map.rdlock();
  status= is_any_slave_channel_running(thread_mask, NULL);
  channel_map.unlock();
  DBUG_RETURN(status);
}
#endif /* HAVE_REPLICATION */
