/* Copyright (c) 2008, 2014, 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 as published by
  the Free Software Foundation; version 2 of the License.

  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 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 "my_pthread.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;

static const TABLE_FIELD_TYPE field_types[]=
{
  {
    { C_STRING_WITH_LEN("THREAD_ID") },
    { C_STRING_WITH_LEN("bigint(20)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("NAME") },
    { C_STRING_WITH_LEN("varchar(128)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("TYPE") },
    { C_STRING_WITH_LEN("varchar(10)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("PROCESSLIST_ID") },
    { C_STRING_WITH_LEN("bigint(20)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("PROCESSLIST_USER") },
    { C_STRING_WITH_LEN("varchar(16)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("PROCESSLIST_HOST") },
    { C_STRING_WITH_LEN("varchar(60)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("PROCESSLIST_DB") },
    { C_STRING_WITH_LEN("varchar(64)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("PROCESSLIST_COMMAND") },
    { C_STRING_WITH_LEN("varchar(16)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("PROCESSLIST_TIME") },
    { C_STRING_WITH_LEN("bigint(20)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("PROCESSLIST_STATE") },
    { C_STRING_WITH_LEN("varchar(64)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("PROCESSLIST_INFO") },
    { C_STRING_WITH_LEN("longtext") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("PARENT_THREAD_ID") },
    { C_STRING_WITH_LEN("bigint(20)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("ROLE") },
    { C_STRING_WITH_LEN("varchar(64)") },
    { NULL, 0}
  },
  {
    { C_STRING_WITH_LEN("INSTRUMENTED") },
    { C_STRING_WITH_LEN("enum(\'YES\',\'NO\')") },
    { NULL, 0}
  }
};

TABLE_FIELD_DEF
table_threads::m_field_def=
{ 14, field_types };

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,
  &m_field_def,
  false /* checked */
};

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_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_enabled= pfs->m_enabled;
  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;

  if (unlikely(! m_row_exists))
    return HA_ERR_RECORD_DELETED;

  /* Set the null bits */
  DBUG_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,
                                 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.
         */
        DBUG_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;
      default:
        DBUG_ASSERT(false);
      }
    }
  }
  return 0;
}

int table_threads::update_row_values(TABLE *table,
                                     const unsigned char *old_buf,
                                     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;
      default:
        DBUG_ASSERT(false);
      }
    }
  }
  return 0;
}

