/* 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 */

/**
  @file storage/perfschema/ha_perfschema.cc
  Performance schema storage engine (implementation).
*/

#include "my_global.h"
#include "my_pthread.h"
#include "my_atomic.h"
#include "sql_plugin.h"
#include "mysql/plugin.h"
#include "ha_perfschema.h"
#include "pfs_engine_table.h"
#include "pfs_column_values.h"
#include "pfs_instr_class.h"
#include "pfs_instr.h"

#ifdef MY_ATOMIC_MODE_DUMMY
/*
  The performance schema can can not function with MY_ATOMIC_MODE_DUMMY,
  a fully functional implementation of MY_ATOMIC should be used instead.
  If the build fails with this error message:
  - either use a different ./configure --with-atomic-ops option
  - or do not build with the performance schema.
*/
#error "The performance schema needs a functional MY_ATOMIC implementation."
#endif

handlerton *pfs_hton= NULL;

static handler* pfs_create_handler(handlerton *hton,
                                   TABLE_SHARE *table,
                                   MEM_ROOT *mem_root)
{
  return new (mem_root) ha_perfschema(hton, table);
}

static int compare_database_names(const char *name1, const char *name2)
{
  if (lower_case_table_names)
    return strcasecmp(name1, name2);
  return strcmp(name1, name2);
}

static const PFS_engine_table_share*
find_table_share(const char *db, const char *name)
{
  DBUG_ENTER("find_table_share");

  if (compare_database_names(db, PERFORMANCE_SCHEMA_str.str) != 0)
    DBUG_RETURN(NULL);

  const PFS_engine_table_share* result;
  result= PFS_engine_table::find_engine_table_share(name);
  DBUG_RETURN(result);
}

static int pfs_init_func(void *p)
{
  DBUG_ENTER("pfs_init_func");

  pfs_hton= reinterpret_cast<handlerton *> (p);

  pfs_hton->state= SHOW_OPTION_YES;
  pfs_hton->create= pfs_create_handler;
  pfs_hton->show_status= pfs_show_status;
  pfs_hton->flags= HTON_ALTER_NOT_SUPPORTED |
    HTON_TEMPORARY_NOT_SUPPORTED |
    HTON_NO_PARTITION;

  /*
    As long as the server implementation keeps using legacy_db_type,
    as for example in mysql_truncate(),
    we can not rely on the fact that different mysqld process will assign
    consistently the same legacy_db_type for a given storage engine name.
    In particular, using different --loose-skip-xxx options between
    ./mysqld --bootstrap
    ./mysqld
    creates bogus .frm forms when bootstrapping the performance schema,
    if we rely on ha_initialize_handlerton to assign a really dynamic value.
    To fix this, a dedicated DB_TYPE is officially assigned to
    the performance schema. See Bug#43039.
  */
  pfs_hton->db_type= DB_TYPE_PERFORMANCE_SCHEMA;

  PFS_engine_table_share::init_all_locks();

  DBUG_RETURN(0);
}

static int pfs_done_func(void *p)
{
  DBUG_ENTER("pfs_done_func");

  pfs_hton= NULL;

  PFS_engine_table_share::delete_all_locks();

  DBUG_RETURN(0);
}

static struct st_mysql_show_var pfs_status_vars[]=
{
  {"Performance_schema_mutex_classes_lost",
    (char*) &mutex_class_lost, SHOW_LONG_NOFLUSH},
  {"Performance_schema_rwlock_classes_lost",
    (char*) &rwlock_class_lost, SHOW_LONG_NOFLUSH},
  {"Performance_schema_cond_classes_lost",
    (char*) &cond_class_lost, SHOW_LONG_NOFLUSH},
  {"Performance_schema_thread_classes_lost",
    (char*) &thread_class_lost, SHOW_LONG_NOFLUSH},
  {"Performance_schema_file_classes_lost",
    (char*) &file_class_lost, SHOW_LONG_NOFLUSH},
  {"Performance_schema_mutex_instances_lost",
    (char*) &mutex_lost, SHOW_LONG},
  {"Performance_schema_rwlock_instances_lost",
    (char*) &rwlock_lost, SHOW_LONG},
  {"Performance_schema_cond_instances_lost",
    (char*) &cond_lost, SHOW_LONG},
  {"Performance_schema_thread_instances_lost",
    (char*) &thread_lost, SHOW_LONG},
  {"Performance_schema_file_instances_lost",
    (char*) &file_lost, SHOW_LONG},
  {"Performance_schema_file_handles_lost",
    (char*) &file_handle_lost, SHOW_LONG},
  {"Performance_schema_locker_lost",
    (char*) &locker_lost, SHOW_LONG},
  /* table shares, can be flushed */
  {"Performance_schema_table_instances_lost",
    (char*) &table_share_lost, SHOW_LONG},
  /* table handles, can be flushed */
  {"Performance_schema_table_handles_lost",
    (char*) &table_lost, SHOW_LONG},
  {NullS, NullS, SHOW_LONG}
};

struct st_mysql_storage_engine pfs_storage_engine=
{ MYSQL_HANDLERTON_INTERFACE_VERSION };

const char* pfs_engine_name= "PERFORMANCE_SCHEMA";

mysql_declare_plugin(perfschema)
{
  MYSQL_STORAGE_ENGINE_PLUGIN,
  &pfs_storage_engine,
  pfs_engine_name,
  "Marc Alff, Oracle", /* Formerly Sun Microsystems, formerly MySQL */
  "Performance Schema",
  PLUGIN_LICENSE_GPL,
  pfs_init_func,                                /* Plugin Init */
  pfs_done_func,                                /* Plugin Deinit */
  0x0001 /* 0.1 */,
  pfs_status_vars,                              /* status variables */
  NULL,                                         /* system variables */
  NULL,                                         /* config options */
  0,                                            /* flags */
}
mysql_declare_plugin_end;

ha_perfschema::ha_perfschema(handlerton *hton, TABLE_SHARE *share)
  : handler(hton, share), m_table_share(NULL), m_table(NULL)
{}

ha_perfschema::~ha_perfschema()
{}

static const char *ha_pfs_exts[]= {
  NullS
};

const char **ha_perfschema::bas_ext() const
{
  return ha_pfs_exts;
}

int ha_perfschema::open(const char *name, int mode, uint test_if_locked)
{
  DBUG_ENTER("ha_perfschema::open");

  m_table_share= find_table_share(table_share->db.str,
                                  table_share->table_name.str);
  if (! m_table_share)
    DBUG_RETURN(HA_ERR_NO_SUCH_TABLE);

  thr_lock_data_init(m_table_share->m_thr_lock_ptr, &m_thr_lock, NULL);
  ref_length= m_table_share->m_ref_length;

  psi_open();

  DBUG_RETURN(0);
}

int ha_perfschema::close(void)
{
  DBUG_ENTER("ha_perfschema::close");
  m_table_share= NULL;
  delete m_table;
  m_table= NULL;

  psi_close();

  DBUG_RETURN(0);
}

int ha_perfschema::write_row(uchar *buf)
{
  int result;

  DBUG_ENTER("ha_perfschema::write_row");

  ha_statistic_increment(&SSV::ha_write_count);
  DBUG_ASSERT(m_table_share);

  if (m_table_share->m_write_row)
    result= m_table_share->m_write_row(table, buf, table->field);
  else
  {
    result= HA_ERR_WRONG_COMMAND;
  }

  DBUG_RETURN(result);
}

void ha_perfschema::use_hidden_primary_key(void)
{
  /*
    This is also called in case of row based replication,
    see TABLE::mark_columns_needed_for_update().
    Add all columns to the read set, but do not touch the write set,
    as some columns in the SETUP_ tables are not writable.
  */
  table->column_bitmaps_set_no_signal(&table->s->all_set, table->write_set);
}

int ha_perfschema::update_row(const uchar *old_data, uchar *new_data)
{
  DBUG_ENTER("ha_perfschema::update_row");

  if (is_executed_by_slave())
    DBUG_RETURN(0);

  DBUG_ASSERT(m_table);
  int result= m_table->update_row(table, old_data, new_data, table->field);
  DBUG_RETURN(result);
}

int ha_perfschema::rnd_init(bool scan)
{
  int result;
  DBUG_ENTER("ha_perfschema::rnd_init");

  DBUG_ASSERT(m_table_share);
  DBUG_ASSERT(m_table_share->m_open_table != NULL);

  stats.records= 0;
  if (m_table == NULL)
    m_table= m_table_share->m_open_table();
  else
    m_table->reset_position();

  result= m_table ? 0 : HA_ERR_OUT_OF_MEM;
  DBUG_RETURN(result);
}

int ha_perfschema::rnd_end(void)
{
  DBUG_ENTER("ha_perfschema::rnd_end");
  DBUG_ASSERT(m_table);
  delete m_table;
  m_table= NULL;
  DBUG_RETURN(0);
}

int ha_perfschema::rnd_next(uchar *buf)
{
  DBUG_ENTER("ha_perfschema::rnd_next");

  DBUG_ASSERT(m_table);
  int result= m_table->rnd_next();
  if (result == 0)
  {
    result= m_table->read_row(table, buf, table->field);
    if (result == 0)
      stats.records++;
  }
  DBUG_RETURN(result);
}

void ha_perfschema::position(const uchar *record)
{
  DBUG_ENTER("ha_perfschema::position");

  DBUG_ASSERT(m_table);
  m_table->get_position(ref);
  DBUG_VOID_RETURN;
}

int ha_perfschema::rnd_pos(uchar *buf, uchar *pos)
{
  DBUG_ENTER("ha_perfschema::rnd_pos");

  DBUG_ASSERT(m_table);
  int result= m_table->rnd_pos(pos);
  if (result == 0)
    result= m_table->read_row(table, buf, table->field);
  DBUG_RETURN(result);
}

int ha_perfschema::info(uint flag)
{
  DBUG_ENTER("ha_perfschema::info");
  DBUG_ASSERT(m_table_share);
  if (flag & HA_STATUS_VARIABLE)
    stats.records= m_table_share->m_records;
  if (flag & HA_STATUS_CONST)
    ref_length= m_table_share->m_ref_length;
  DBUG_RETURN(0);
}

int ha_perfschema::delete_all_rows(void)
{
  int result;

  DBUG_ENTER("ha_perfschema::delete_all_rows");

  if (is_executed_by_slave())
    DBUG_RETURN(0);

  DBUG_ASSERT(m_table_share);
  if (m_table_share->m_delete_all_rows)
    result= m_table_share->m_delete_all_rows();
  else
  {
    result= HA_ERR_WRONG_COMMAND;
  }
  DBUG_RETURN(result);
}

int ha_perfschema::truncate()
{
  return delete_all_rows();
}

THR_LOCK_DATA **ha_perfschema::store_lock(THD *thd,
                                       THR_LOCK_DATA **to,
                                       enum thr_lock_type lock_type)
{
  if (lock_type != TL_IGNORE && m_thr_lock.type == TL_UNLOCK)
    m_thr_lock.type= lock_type;
  *to++= &m_thr_lock;
  m_thr_lock.m_psi= m_psi;
  return to;
}

int ha_perfschema::delete_table(const char *name)
{
  DBUG_ENTER("ha_perfschema::delete_table");
  DBUG_RETURN(0);
}

int ha_perfschema::rename_table(const char * from, const char * to)
{
  DBUG_ENTER("ha_perfschema::rename_table ");
  DBUG_RETURN(HA_ERR_WRONG_COMMAND);
}

int ha_perfschema::create(const char *name, TABLE *table_arg,
                          HA_CREATE_INFO *create_info)
{
  DBUG_ENTER("ha_perfschema::create");
  DBUG_ASSERT(table_arg);
  DBUG_ASSERT(table_arg->s);
  if (find_table_share(table_arg->s->db.str,
                       table_arg->s->table_name.str))
  {
    /*
      Attempting to create a known performance schema table.
      Allowing the create, to create .FRM files,
      for the initial database install, and mysql_upgrade.
      This should fail once .FRM are removed.
    */
    DBUG_RETURN(0);
  }
  /*
    This is not a general purpose engine.
    Failure to CREATE TABLE is the expected result.
  */
  DBUG_RETURN(HA_ERR_WRONG_COMMAND);
}

void ha_perfschema::print_error(int error, myf errflag)
{
  switch (error)
  {
    case HA_ERR_TABLE_NEEDS_UPGRADE:
      /*
        The error message for ER_TABLE_NEEDS_UPGRADE refers to REPAIR table,
        which does not apply to performance schema tables.
      */
      my_error(ER_WRONG_NATIVE_TABLE_STRUCTURE, MYF(0),
               table_share->db.str, table_share->table_name.str);
      break;
    case HA_ERR_WRONG_COMMAND:
      /*
        The performance schema is not a general purpose storage engine,
        some operations are not supported, by design.
        We do not want to print "Command not supported",
        which gives the impression that a command implementation is missing,
        and that the failure should be considered a bug.
        We print "Invalid performance_schema usage." instead,
        to emphasise that the operation attempted is not meant to be legal,
        and that the failure returned is indeed the expected result.
      */
      my_error(ER_WRONG_PERFSCHEMA_USAGE, MYF(0));
      break;
    default:
     handler::print_error(error, errflag);
     break;
  }
}

