/* Copyright (c) 2008, 2023, 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,
  51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */

#include "my_global.h"
#include "my_thread.h"
#include "table_threads.h"
#include "sql_parse.h"
#include "pfs_instr_class.h"
#include "pfs_instr.h"

THR_LOCK table_threads::m_table_lock;

PFS_engine_table_share_state
table_threads::m_share_state = {
  false /* m_checked */
};

PFS_engine_table_share
table_threads::m_share=
{
  { C_STRING_WITH_LEN("threads") },
  &pfs_updatable_acl,
  table_threads::create,
  NULL, /* write_row */
  NULL, /* delete_all_rows */
  cursor_by_thread::get_row_count,
  sizeof(PFS_simple_index), /* ref length */
  &m_table_lock,
  { C_STRING_WITH_LEN("CREATE TABLE threads("
                      "THREAD_ID BIGINT unsigned not null comment 'A unique thread identifier.',"
                      "NAME VARCHAR(128) not null comment 'Name associated with the server''s thread instrumentation code, for example thread/sql/main for the server''s main() function, and thread/sql/one_connection for a user connection.',"
                      "TYPE VARCHAR(10) not null comment 'FOREGROUND or BACKGROUND, depending on the thread type. User connection threads are FOREGROUND, internal server threads are BACKGROUND.',"
                      "PROCESSLIST_ID BIGINT unsigned comment 'The PROCESSLIST.ID value for threads displayed in the INFORMATION_SCHEMA.PROCESSLIST table, or 0 for background threads. Also corresponds with the CONNECTION_ID() return value for the thread.',"
                      "PROCESSLIST_USER VARCHAR(" USERNAME_CHAR_LENGTH_STR ") comment 'Foreground thread user, or NULL for a background thread.',"
                      "PROCESSLIST_HOST VARCHAR(" HOSTNAME_LENGTH_STR ") comment 'Foreground thread host, or NULL for a background thread.',"
                      "PROCESSLIST_DB VARCHAR(64) comment 'Thread''s default database, or NULL if none exists.',"
                      "PROCESSLIST_COMMAND VARCHAR(16) comment 'Type of command executed by the thread. These correspond to the the COM_xxx client/server protocol commands, and the Com_xxx status variables. See Thread Command Values.',"
                      "PROCESSLIST_TIME BIGINT comment 'Time in seconds the thread has been in its current state.',"
                      "PROCESSLIST_STATE VARCHAR(64) comment 'Action, event or state indicating what the thread is doing.',"
                      "PROCESSLIST_INFO LONGTEXT comment 'Statement being executed by the thread, or NULL if a statement is not being executed. If a statement results in calling other statements, such as for a stored procedure, the innermost statement from the stored procedure is shown here.',"
                      "PARENT_THREAD_ID BIGINT unsigned comment 'THREAD_ID of the parent thread, if any. Subthreads can for example be spawned as a result of INSERT DELAYED statements.',"
                      "ROLE VARCHAR(64) comment 'Unused.',"
                      "INSTRUMENTED ENUM ('YES', 'NO') not null comment 'YES or NO for Whether the thread is instrumented or not. For foreground threads, the initial value is determined by whether there''s a user/host match in the setup_actors table. Subthreads are again matched, while for background threads, this will be set to YES by default. To monitor events that the thread executes, INSTRUMENTED must be YES and the thread_instrumentation consumer in the setup_consumers table must also be YES.',"
                      "HISTORY ENUM ('YES', 'NO') not null comment 'Whether to log historical events for the thread.',"
                      "CONNECTION_TYPE VARCHAR(16) comment 'The protocol used to establish the connection, or NULL for background threads.',"
                      "THREAD_OS_ID BIGINT unsigned comment 'The thread or task identifier as defined by the underlying operating system, if there is one.')") },
  false, /* m_perpetual */
  false, /* m_optional */
  &m_share_state
};

PFS_engine_table* table_threads::create()
{
  return new table_threads();
}

table_threads::table_threads()
  : cursor_by_thread(& m_share),
  m_row_exists(false)
{}

void table_threads::make_row(PFS_thread *pfs)
{
  pfs_optimistic_state lock;
  pfs_optimistic_state session_lock;
  pfs_optimistic_state stmt_lock;
  PFS_stage_class *stage_class;
  PFS_thread_class *safe_class;

  m_row_exists= false;

  /* Protect this reader against thread termination */
  pfs->m_lock.begin_optimistic_lock(&lock);

  safe_class= sanitize_thread_class(pfs->m_class);
  if (unlikely(safe_class == NULL))
    return;

  m_row.m_thread_internal_id= pfs->m_thread_internal_id;
  m_row.m_parent_thread_internal_id= pfs->m_parent_thread_internal_id;
  m_row.m_processlist_id= pfs->m_processlist_id;
  m_row.m_thread_os_id= pfs->m_thread_os_id;
  m_row.m_name= safe_class->m_name;
  m_row.m_name_length= safe_class->m_name_length;

  /* Protect this reader against session attribute changes */
  pfs->m_session_lock.begin_optimistic_lock(&session_lock);

  m_row.m_username_length= pfs->m_username_length;
  if (unlikely(m_row.m_username_length > sizeof(m_row.m_username)))
    return;
  if (m_row.m_username_length != 0)
    memcpy(m_row.m_username, pfs->m_username, m_row.m_username_length);

  m_row.m_hostname_length= pfs->m_hostname_length;
  if (unlikely(m_row.m_hostname_length > sizeof(m_row.m_hostname)))
    return;
  if (m_row.m_hostname_length != 0)
    memcpy(m_row.m_hostname, pfs->m_hostname, m_row.m_hostname_length);

  if (! pfs->m_session_lock.end_optimistic_lock(& session_lock))
  {
    /*
      One of the columns:
      - PROCESSLIST_USER
      - PROCESSLIST_HOST
      is being updated.
      Do not discard the entire row.
      Do not loop waiting for a stable value.
      Just return NULL values.
    */
    m_row.m_username_length= 0;
    m_row.m_hostname_length= 0;
  }

  /* Protect this reader against statement attributes changes */
  pfs->m_stmt_lock.begin_optimistic_lock(&stmt_lock);

  m_row.m_dbname_length= pfs->m_dbname_length;
  if (unlikely(m_row.m_dbname_length > sizeof(m_row.m_dbname)))
    return;
  if (m_row.m_dbname_length != 0)
    memcpy(m_row.m_dbname, pfs->m_dbname, m_row.m_dbname_length);

  m_row.m_processlist_info_ptr= & pfs->m_processlist_info[0];
  m_row.m_processlist_info_length= pfs->m_processlist_info_length;

  if (! pfs->m_stmt_lock.end_optimistic_lock(& stmt_lock))
  {
    /*
      One of the columns:
      - PROCESSLIST_DB
      - PROCESSLIST_INFO
      is being updated.
      Do not discard the entire row.
      Do not loop waiting for a stable value.
      Just return NULL values.
    */
    m_row.m_dbname_length= 0;
    m_row.m_processlist_info_length= 0;
  }

  /* Dirty read, sanitize the command. */
  m_row.m_command= pfs->m_command;
  if ((m_row.m_command < 0) || (m_row.m_command > COM_END))
    m_row.m_command= COM_END;

  m_row.m_start_time= pfs->m_start_time;

  stage_class= find_stage_class(pfs->m_stage);
  if (stage_class != NULL)
  {
    m_row.m_processlist_state_ptr= stage_class->m_name + stage_class->m_prefix_length;
    m_row.m_processlist_state_length= stage_class->m_name_length - stage_class->m_prefix_length;
  }
  else
  {
    m_row.m_processlist_state_length= 0;
  }
  m_row.m_connection_type = pfs->m_connection_type;


  m_row.m_enabled= pfs->m_enabled;
  m_row.m_history= pfs->m_history;
  m_row.m_psi= pfs;

  if (pfs->m_lock.end_optimistic_lock(& lock))
    m_row_exists= true;
}

int table_threads::read_row_values(TABLE *table,
                                   unsigned char *buf,
                                   Field **fields,
                                   bool read_all)
{
  Field *f;
  const char *str= NULL;
  size_t len= 0;

  if (unlikely(! m_row_exists))
    return HA_ERR_RECORD_DELETED;

  /* Set the null bits */
  assert(table->s->null_bytes == 2);
  buf[0]= 0;
  buf[1]= 0;

  for (; (f= *fields) ; fields++)
  {
    if (read_all || bitmap_is_set(table->read_set, f->field_index))
    {
      switch(f->field_index)
      {
      case 0: /* THREAD_ID */
        set_field_ulonglong(f, m_row.m_thread_internal_id);
        break;
      case 1: /* NAME */
        set_field_varchar_utf8(f, m_row.m_name, m_row.m_name_length);
        break;
      case 2: /* TYPE */
        if (m_row.m_processlist_id != 0)
          set_field_varchar_utf8(f, "FOREGROUND", 10);
        else
          set_field_varchar_utf8(f, "BACKGROUND", 10);
        break;
      case 3: /* PROCESSLIST_ID */
        if (m_row.m_processlist_id != 0)
          set_field_ulonglong(f, m_row.m_processlist_id);
        else
          f->set_null();
        break;
      case 4: /* PROCESSLIST_USER */
        if (m_row.m_username_length > 0)
          set_field_varchar_utf8(f, m_row.m_username,
                                 m_row.m_username_length);
        else
          f->set_null();
        break;
      case 5: /* PROCESSLIST_HOST */
        if (m_row.m_hostname_length > 0)
          set_field_varchar_utf8(f, m_row.m_hostname,
                                 m_row.m_hostname_length);
        else
          f->set_null();
        break;
      case 6: /* PROCESSLIST_DB */
        if (m_row.m_dbname_length > 0)
          set_field_varchar_utf8(f, m_row.m_dbname,
                                 m_row.m_dbname_length);
        else
          f->set_null();
        break;
      case 7: /* PROCESSLIST_COMMAND */
        if (m_row.m_processlist_id != 0)
          set_field_varchar_utf8(f, command_name[m_row.m_command].str,
                                 (uint)command_name[m_row.m_command].length);
        else
          f->set_null();
        break;
      case 8: /* PROCESSLIST_TIME */
        if (m_row.m_start_time)
        {
          time_t now= my_time(0);
          ulonglong elapsed= (now > m_row.m_start_time ? now - m_row.m_start_time : 0);
          set_field_ulonglong(f, elapsed);
        }
        else
          f->set_null();
        break;
      case 9: /* PROCESSLIST_STATE */
        /* This column's datatype is declared as varchar(64). Thread's state
           message cannot be more than 64 characters. Otherwise, we will end up
           in 'data truncated' warning/error (depends sql_mode setting) when
           server is updating this column for those threads. To prevent this
           kind of issue, an assert is added.
         */
        assert(m_row.m_processlist_state_length <= f->char_length());
        if (m_row.m_processlist_state_length > 0)
          set_field_varchar_utf8(f, m_row.m_processlist_state_ptr,
                                 m_row.m_processlist_state_length);
        else
          f->set_null();
        break;
      case 10: /* PROCESSLIST_INFO */
        if (m_row.m_processlist_info_length > 0)
          set_field_longtext_utf8(f, m_row.m_processlist_info_ptr,
                                  m_row.m_processlist_info_length);
        else
          f->set_null();
        break;
      case 11: /* PARENT_THREAD_ID */
        if (m_row.m_parent_thread_internal_id != 0)
          set_field_ulonglong(f, m_row.m_parent_thread_internal_id);
        else
          f->set_null();
        break;
      case 12: /* ROLE */
        f->set_null();
        break;
      case 13: /* INSTRUMENTED */
        set_field_enum(f, m_row.m_enabled ? ENUM_YES : ENUM_NO);
        break;
      case 14: /* HISTORY */
        set_field_enum(f, m_row.m_history ? ENUM_YES : ENUM_NO);
        break;
      case 15: /* CONNECTION_TYPE */
        str= vio_type_name(m_row.m_connection_type, & len);
        if (len > 0)
          set_field_varchar_utf8(f, str, (uint)len);
        else
          f->set_null();
        break;
      case 16: /* THREAD_OS_ID */
        if (m_row.m_thread_os_id > 0)
          set_field_ulonglong(f, m_row.m_thread_os_id);
        else
          f->set_null();
        break;
      default:
        assert(false);
      }
    }
  }
  return 0;
}

int table_threads::update_row_values(TABLE *table,
                                     const unsigned char *old_buf,
                                     const unsigned char *new_buf,
                                     Field **fields)
{
  Field *f;
  enum_yes_no value;

  for (; (f= *fields) ; fields++)
  {
    if (bitmap_is_set(table->write_set, f->field_index))
    {
      switch(f->field_index)
      {
      case 0: /* THREAD_ID */
      case 1: /* NAME */
      case 2: /* TYPE */
      case 3: /* PROCESSLIST_ID */
      case 4: /* PROCESSLIST_USER */
      case 5: /* PROCESSLIST_HOST */
      case 6: /* PROCESSLIST_DB */
      case 7: /* PROCESSLIST_COMMAND */
      case 8: /* PROCESSLIST_TIME */
      case 9: /* PROCESSLIST_STATE */
      case 10: /* PROCESSLIST_INFO */
      case 11: /* PARENT_THREAD_ID */
      case 12: /* ROLE */
        return HA_ERR_WRONG_COMMAND;
      case 13: /* INSTRUMENTED */
        value= (enum_yes_no) get_field_enum(f);
        m_row.m_psi->set_enabled((value == ENUM_YES) ? true : false);
        break;
      case 14: /* HISTORY */
        value= (enum_yes_no) get_field_enum(f);
        m_row.m_psi->set_history((value == ENUM_YES) ? true : false);
        break;
      case 15: /* CONNECTION_TYPE */
      case 16: /* THREAD_OS_ID */
        return HA_ERR_WRONG_COMMAND;
      default:
        assert(false);
      }
    }
  }
  return 0;
}