/* Copyright (c) 2010, 2015, 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 */

/**
  @file storage/perfschema/pfs_events_statements.cc
  Events statements data structures (implementation).
*/

#include "my_global.h"
#include "my_sys.h"
#include "pfs_global.h"
#include "pfs_instr_class.h"
#include "pfs_instr.h"
#include "pfs_account.h"
#include "pfs_host.h"
#include "pfs_user.h"
#include "pfs_events_statements.h"
#include "pfs_atomic.h"
#include "m_string.h"

size_t events_statements_history_long_size= 0;
/** Consumer flag for table EVENTS_STATEMENTS_CURRENT. */
bool flag_events_statements_current= false;
/** Consumer flag for table EVENTS_STATEMENTS_HISTORY. */
bool flag_events_statements_history= false;
/** Consumer flag for table EVENTS_STATEMENTS_HISTORY_LONG. */
bool flag_events_statements_history_long= false;

/** True if EVENTS_STATEMENTS_HISTORY_LONG circular buffer is full. */
bool events_statements_history_long_full= false;
/** Index in EVENTS_STATEMENTS_HISTORY_LONG circular buffer. */
volatile uint32 events_statements_history_long_index= 0;
/** EVENTS_STATEMENTS_HISTORY_LONG circular buffer. */
PFS_events_statements *events_statements_history_long_array= NULL;
static unsigned char *h_long_stmts_digest_token_array= NULL;

/**
  Initialize table EVENTS_STATEMENTS_HISTORY_LONG.
  @param events_statements_history_long_sizing       table sizing
*/
int init_events_statements_history_long(size_t events_statements_history_long_sizing)
{
  events_statements_history_long_size= events_statements_history_long_sizing;
  events_statements_history_long_full= false;
  PFS_atomic::store_u32(&events_statements_history_long_index, 0);

  if (events_statements_history_long_size == 0)
    return 0;

  events_statements_history_long_array=
    PFS_MALLOC_ARRAY(events_statements_history_long_size, sizeof(PFS_events_statements),
                     PFS_events_statements, MYF(MY_ZEROFILL));

  if (events_statements_history_long_array == NULL)
  {
    cleanup_events_statements_history_long();
    return 1;
  }

  if (pfs_max_digest_length > 0)
  {
    /* Size of each digest token array. */
    size_t digest_text_size= pfs_max_digest_length * sizeof(unsigned char);

    h_long_stmts_digest_token_array=
      PFS_MALLOC_ARRAY(events_statements_history_long_size, digest_text_size, 
                       unsigned char, MYF(MY_ZEROFILL));
    if (h_long_stmts_digest_token_array == NULL)
    {
      cleanup_events_statements_history_long();
      return 1;
    }
  }

  for (size_t index= 0; index < events_statements_history_long_size; index++)
  {
    events_statements_history_long_array[index].m_digest_storage.reset(h_long_stmts_digest_token_array
                                                                       + index * pfs_max_digest_length, pfs_max_digest_length);
  }

  return 0;
}

/** Cleanup table EVENTS_STATEMENTS_HISTORY_LONG. */
void cleanup_events_statements_history_long(void)
{
  pfs_free(events_statements_history_long_array);
  pfs_free(h_long_stmts_digest_token_array);
  events_statements_history_long_array= NULL;
  h_long_stmts_digest_token_array= NULL;
}

static inline void copy_events_statements(PFS_events_statements *dest,
                                      const PFS_events_statements *source)
{
  /* Copy all attributes except DIGEST */
  memcpy(dest, source, my_offsetof(PFS_events_statements, m_digest_storage));

  /* Copy DIGEST */
  dest->m_digest_storage.copy(& source->m_digest_storage);
}

/**
  Insert a statement record in table EVENTS_STATEMENTS_HISTORY.
  @param thread             thread that executed the wait
  @param statement          record to insert
*/
void insert_events_statements_history(PFS_thread *thread, PFS_events_statements *statement)
{
  if (unlikely(events_statements_history_per_thread == 0))
    return;

  DBUG_ASSERT(thread->m_statements_history != NULL);

  uint index= thread->m_statements_history_index;

  /*
    A concurrent thread executing TRUNCATE TABLE EVENTS_STATEMENTS_CURRENT
    could alter the data that this thread is inserting,
    causing a potential race condition.
    We are not testing for this and insert a possibly empty record,
    to make this thread (the writer) faster.
    This is ok, the readers of m_statements_history will filter this out.
  */
  copy_events_statements(&thread->m_statements_history[index], statement);

  index++;
  if (index >= events_statements_history_per_thread)
  {
    index= 0;
    thread->m_statements_history_full= true;
  }
  thread->m_statements_history_index= index;
}

/**
  Insert a statement record in table EVENTS_STATEMENTS_HISTORY_LONG.
  @param statement              record to insert
*/
void insert_events_statements_history_long(PFS_events_statements *statement)
{
  if (unlikely(events_statements_history_long_size == 0))
    return ;

  DBUG_ASSERT(events_statements_history_long_array != NULL);

  uint index= PFS_atomic::add_u32(&events_statements_history_long_index, 1);

  index= index % events_statements_history_long_size;
  if (index == 0)
    events_statements_history_long_full= true;

  /* See related comment in insert_events_statements_history. */
  copy_events_statements(&events_statements_history_long_array[index], statement);
}

/** Reset table EVENTS_STATEMENTS_CURRENT data. */
void reset_events_statements_current(void)
{
  PFS_thread *pfs_thread= thread_array;
  PFS_thread *pfs_thread_last= thread_array + thread_max;

  for ( ; pfs_thread < pfs_thread_last; pfs_thread++)
  {
    PFS_events_statements *pfs_stmt= & pfs_thread->m_statement_stack[0];
    PFS_events_statements *pfs_stmt_last= pfs_stmt + statement_stack_max;

    for ( ; pfs_stmt < pfs_stmt_last; pfs_stmt++)
      pfs_stmt->m_class= NULL;
  }
}

/** Reset table EVENTS_STATEMENTS_HISTORY data. */
void reset_events_statements_history(void)
{
  PFS_thread *pfs_thread= thread_array;
  PFS_thread *pfs_thread_last= thread_array + thread_max;

  for ( ; pfs_thread < pfs_thread_last; pfs_thread++)
  {
    PFS_events_statements *pfs= pfs_thread->m_statements_history;
    PFS_events_statements *pfs_last= pfs + events_statements_history_per_thread;

    pfs_thread->m_statements_history_index= 0;
    pfs_thread->m_statements_history_full= false;
    for ( ; pfs < pfs_last; pfs++)
      pfs->m_class= NULL;
  }
}

/** Reset table EVENTS_STATEMENTS_HISTORY_LONG data. */
void reset_events_statements_history_long(void)
{
  PFS_atomic::store_u32(&events_statements_history_long_index, 0);
  events_statements_history_long_full= false;

  PFS_events_statements *pfs= events_statements_history_long_array;
  PFS_events_statements *pfs_last= pfs + events_statements_history_long_size;
  for ( ; pfs < pfs_last; pfs++)
    pfs->m_class= NULL;
}

/** Reset table EVENTS_STATEMENTS_SUMMARY_BY_THREAD_BY_EVENT_NAME data. */
void reset_events_statements_by_thread()
{
  PFS_thread *thread= thread_array;
  PFS_thread *thread_last= thread_array + thread_max;
  PFS_account *account;
  PFS_user *user;
  PFS_host *host;

  for ( ; thread < thread_last; thread++)
  {
    if (thread->m_lock.is_populated())
    {
      account= sanitize_account(thread->m_account);
      user= sanitize_user(thread->m_user);
      host= sanitize_host(thread->m_host);
      aggregate_thread_statements(thread, account, user, host);
    }
  }
}

/** Reset table EVENTS_STATEMENTS_SUMMARY_BY_ACCOUNT_BY_EVENT_NAME data. */
void reset_events_statements_by_account()
{
  PFS_account *pfs= account_array;
  PFS_account *pfs_last= account_array + account_max;
  PFS_user *user;
  PFS_host *host;

  for ( ; pfs < pfs_last; pfs++)
  {
    if (pfs->m_lock.is_populated())
    {
      user= sanitize_user(pfs->m_user);
      host= sanitize_host(pfs->m_host);
      pfs->aggregate_statements(user, host);
    }
  }
}

/** Reset table EVENTS_STATEMENTS_SUMMARY_BY_USER_BY_EVENT_NAME data. */
void reset_events_statements_by_user()
{
  PFS_user *pfs= user_array;
  PFS_user *pfs_last= user_array + user_max;

  for ( ; pfs < pfs_last; pfs++)
  {
    if (pfs->m_lock.is_populated())
      pfs->aggregate_statements();
  }
}

/** Reset table EVENTS_STATEMENTS_SUMMARY_BY_HOST_BY_EVENT_NAME data. */
void reset_events_statements_by_host()
{
  PFS_host *pfs= host_array;
  PFS_host *pfs_last= host_array + host_max;

  for ( ; pfs < pfs_last; pfs++)
  {
    if (pfs->m_lock.is_populated())
      pfs->aggregate_statements();
  }
}

/** Reset table EVENTS_STATEMENTS_GLOBAL_BY_EVENT_NAME data. */
void reset_events_statements_global()
{
  PFS_statement_stat *stat= global_instr_class_statements_array;
  PFS_statement_stat *stat_last= global_instr_class_statements_array + statement_class_max;

  for ( ; stat < stat_last; stat++)
    stat->reset();
}

