/* Copyright (C) 2004 MySQL AB

   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, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */

#if defined(__GNUC__) && defined(USE_PRAGMA_IMPLEMENTATION)
#pragma implementation
#endif

#include "instance_map.h"

#include <my_global.h>
#include <m_ctype.h>
#include <mysql_com.h>

#include "buffer.h"
#include "instance.h"
#include "log.h"
#include "mysqld_error.h"
#include "mysql_manager_error.h"
#include "options.h"
#include "priv.h"

C_MODE_START

/**
  HASH-routines: get key of instance for storing in hash.
*/

static byte* get_instance_key(const byte* u, uint* len,
                          my_bool __attribute__((unused)) t)
{
  const Instance *instance= (const Instance *) u;
  *len= instance->options.instance_name.length;
  return (byte *) instance->options.instance_name.str;
}

/**
  HASH-routines: cleanup handler.
*/

static void delete_instance(void *u)
{
  Instance *instance= (Instance *) u;
  delete instance;
}

/**
  The option handler to pass to the process_default_option_files function.

  SYNOPSIS
    process_option()
    ctx               Handler context. Here it is an instance_map structure.
    group_name        The name of the group the option belongs to.
    option            The very option to be processed. It is already
                      prepared to be used in argv (has -- prefix)

  DESCRIPTION

    This handler checks whether a group is an instance group and adds
    an option to the appropriate instance class. If this is the first
    occurence of an instance name, we'll also create the instance
    with such name and add it to the instance map.

  RETURN
    0 - ok
    1 - error occured
*/

static int process_option(void *ctx, const char *group, const char *option)
{
  Instance_map *map= (Instance_map*) ctx;
  LEX_STRING group_str;

  group_str.str= (char *) group;
  group_str.length= strlen(group);

  return map->process_one_option(&group_str, option);
}

C_MODE_END


/**
  Parse option string.

  SYNOPSIS
    parse_option()
      option_str        [IN] option string (e.g. "--name=value")
      option_name_buf   [OUT] parsed name of the option.
                        Must be of (MAX_OPTION_LEN + 1) size.
      option_value_buf  [OUT] parsed value of the option.
                        Must be of (MAX_OPTION_LEN + 1) size.

  DESCRIPTION
    This is an auxiliary function and should not be used externally. It is
    intended to parse whole option string into option name and option value.
*/

static void parse_option(const char *option_str,
                         char *option_name_buf,
                         char *option_value_buf)
{
  const char *eq_pos;
  const char *ptr= option_str;

  while (*ptr == '-')
    ++ptr;

  strmake(option_name_buf, ptr, MAX_OPTION_LEN + 1);

  eq_pos= strchr(ptr, '=');
  if (eq_pos)
  {
    option_name_buf[eq_pos - ptr]= 0;
    strmake(option_value_buf, eq_pos + 1, MAX_OPTION_LEN + 1);
  }
  else
  {
    option_value_buf[0]= 0;
  }
}


/**
  Process one option from the configuration file.

  SYNOPSIS
    Instance_map::process_one_option()
      group         group name
      option        option string (e.g. "--name=value")

  DESCRIPTION
    This is an auxiliary function and should not be used externally.
    It is used only by flush_instances(), which pass it to
    process_option(). The caller ensures proper locking
    of the instance map object.
*/
  /*
    Process a given option and assign it to appropricate instance. This is
    required for the option handler, passed to my_search_option_files().
  */

int Instance_map::process_one_option(const LEX_STRING *group,
                                     const char *option)
{
  Instance *instance= NULL;

  if (!Instance::is_name_valid(group))
  {
    /*
      Current section name is not a valid instance name.
      We should skip it w/o error.
    */
    return 0;
  }

  if (!(instance= (Instance *) hash_search(&hash, (byte *) group->str,
                                           group->length)))
  {
    if (!(instance= new Instance()))
      return 1;

    if (instance->init(group) || add_instance(instance))
    {
      delete instance;
      return 1;
    }

    if (instance->is_mysqld_compatible())
      log_info("Warning: instance name '%s' is mysqld-compatible.",
               (const char *) group->str);

    log_info("mysqld instance '%s' has been added successfully.",
             (const char *) group->str);
  }

  if (option)
  {
    char option_name[MAX_OPTION_LEN + 1];
    char option_value[MAX_OPTION_LEN + 1];

    parse_option(option, option_name, option_value);

    if (instance->is_mysqld_compatible() &&
        Instance_options::is_option_im_specific(option_name))
    {
      log_info("Warning: configuration of mysqld-compatible instance '%s' "
               "contains IM-specific option '%s'. "
               "This breaks backward compatibility for the configuration file.",
               (const char *) group->str,
               (const char *) option_name);
    }

    Named_value option(option_name, option_value);

    if (instance->options.set_option(&option))
      return 1;   /* the instance'll be deleted when we destroy the map */
  }

  return 0;
}


/**
  Instance_map constructor.
*/

Instance_map::Instance_map()
{
  pthread_mutex_init(&LOCK_instance_map, 0);
}


/**
  Initialize Instance_map internals.
*/

bool Instance_map::init()
{
  return hash_init(&hash, default_charset_info, START_HASH_SIZE, 0, 0,
                   get_instance_key, delete_instance, 0);
}


/**
  Reset Instance_map data.
*/

bool Instance_map::reset()
{
  hash_free(&hash);
  return init();
}


/**
  Instance_map destructor.
*/

Instance_map::~Instance_map()
{
  lock();

  /*
    NOTE: it's necessary to synchronize on each instance before removal,
    because Instance-monitoring thread can be still alive an hold the mutex
    (because it is detached and we have no control over it).
  */

  while (true)
  {
    Iterator it(this);
    Instance *instance= it.next();

    if (!instance)
      break;

    instance->lock();
    instance->unlock();

    remove_instance(instance);
  }

  hash_free(&hash);
  unlock();

  pthread_mutex_destroy(&LOCK_instance_map);
}


/**
  Lock Instance_map.
*/

void Instance_map::lock()
{
  pthread_mutex_lock(&LOCK_instance_map);
}


/**
  Unlock Instance_map.
*/

void Instance_map::unlock()
{
  pthread_mutex_unlock(&LOCK_instance_map);
}


/**
  Check if there is an active instance or not.
*/

bool Instance_map::is_there_active_instance()
{
  Instance *instance;
  Iterator iterator(this);

  while ((instance= iterator.next()))
  {
    bool active_instance_found;

    instance->lock();
    active_instance_found= instance->is_active();
    instance->unlock();

    if (active_instance_found)
      return TRUE;
  }

  return FALSE;
}


/**
  Add an instance into the internal hash.

  MT-NOTE: Instance Map must be locked before calling the operation.
*/

int Instance_map::add_instance(Instance *instance)
{
  return my_hash_insert(&hash, (byte *) instance);
}


/**
  Remove instance from the internal hash.

  MT-NOTE: Instance Map must be locked before calling the operation.
*/

int Instance_map::remove_instance(Instance *instance)
{
  return hash_delete(&hash, (byte *) instance);
}


/**
  Create a new instance and register it in the internal hash.

  MT-NOTE: Instance Map must be locked before calling the operation.
*/

int Instance_map::create_instance(const LEX_STRING *instance_name,
                                  const Named_value_arr *options)
{
  Instance *instance= new Instance();

  if (!instance)
  {
    log_error("Can not allocate instance (name: '%s').",
              (const char *) instance_name->str);
    return ER_OUT_OF_RESOURCES;
  }

  if (instance->init(instance_name))
  {
    log_error("Can not initialize instance (name: '%s').",
              (const char *) instance_name->str);
    delete instance;
    return ER_OUT_OF_RESOURCES;
  }

  for (int i= 0; options && i < options->get_size(); ++i)
  {
    Named_value option= options->get_element(i);

    if (instance->is_mysqld_compatible() &&
        Instance_options::is_option_im_specific(option.get_name()))
    {
      log_error("IM-option (%s) can not be used "
                "in configuration of mysqld-compatible instance (%s).",
                (const char *) option.get_name(),
                (const char *) instance_name->str);
      delete instance;
      return ER_INCOMPATIBLE_OPTION;
    }

    instance->options.set_option(&option);
  }

  if (instance->is_mysqld_compatible())
    log_info("Warning: instance name '%s' is mysqld-compatible.",
             (const char *) instance_name->str);

  if (instance->complete_initialization())
  {
    log_error("Can not complete initialization of instance (name: '%s').",
              (const char *) instance_name->str);
    delete instance;
    return ER_OUT_OF_RESOURCES;
    /* TODO: return more appropriate error code in this case. */
  }

  if (add_instance(instance))
  {
    log_error("Can not register instance (name: '%s').",
              (const char *) instance_name->str);
    delete instance;
    return ER_OUT_OF_RESOURCES;
  }

  return 0;
}


/**
  Return a pointer to the instance or NULL, if there is no such instance.

  MT-NOTE: Instance Map must be locked before calling the operation.
*/

Instance * Instance_map::find(const LEX_STRING *name)
{
  return (Instance *) hash_search(&hash, (byte *) name->str, name->length);
}


/**
  Init instances command line arguments after all options have been loaded.
*/

bool Instance_map::complete_initialization()
{
  bool mysqld_found;

  /* Complete initialization of all registered instances. */

  for (uint i= 0; i < hash.records; ++i)
  {
    Instance *instance= (Instance *) hash_element(&hash, i);

    if (instance->complete_initialization())
      return TRUE;
  }

  /* That's all if we are runnning in an ordinary mode. */

  if (!Options::Main::mysqld_safe_compatible)
    return FALSE;

  /* In mysqld-compatible mode we must ensure that there 'mysqld' instance. */

  mysqld_found= find(&Instance::DFLT_INSTANCE_NAME) != NULL;

  if (mysqld_found)
    return FALSE;

  if (create_instance(&Instance::DFLT_INSTANCE_NAME, NULL))
  {
    log_error("Can not create default instance.");
    return TRUE;
  }

  switch (create_instance_in_file(&Instance::DFLT_INSTANCE_NAME, NULL))
  {
  case 0:
  case ER_CONF_FILE_DOES_NOT_EXIST:
    /*
      Continue if the instance has been added to the config file
      successfully, or the config file just does not exist.
    */
    break;

  default:
    log_error("Can not add default instance to the config file.");

    Instance *instance= find(&Instance::DFLT_INSTANCE_NAME);

    if (instance)
      remove_instance(instance); /* instance is deleted here. */

    return TRUE;
  }

  return FALSE;
}


/**
  Load options from config files and create appropriate instance
  structures.
*/

int Instance_map::load()
{
  int argc= 1;
  /* this is a dummy variable for search_option_files() */
  uint args_used= 0;
  const char *argv_options[3];
  char **argv= (char **) &argv_options;
  char defaults_file_arg[FN_REFLEN];

  /* the name of the program may be orbitrary here in fact */
  argv_options[0]= "mysqlmanager";

  /*
    If the option file was forced by the user when starting
    the IM with --defaults-file=xxxx, make sure it is also
    passed as --defaults-file, not only as Options::config_file.
    This is important for option files given with relative path:
    e.g. --defaults-file=my.cnf.
    Otherwise my_search_option_files will treat "my.cnf" as a group
    name and start looking for files named "my.cnf.cnf" in all
    default dirs. Which is not what we want.
  */
  if (Options::Main::is_forced_default_file)
  {
    snprintf(defaults_file_arg, FN_REFLEN, "--defaults-file=%s",
             Options::Main::config_file);

    argv_options[1]= defaults_file_arg;
    argv_options[2]= '\0';

    argc= 2;
  }
  else
    argv_options[1]= '\0';

  /*
    If the routine failed, we'll simply fallback to defaults in
    complete_initialization().
  */
  if (my_search_option_files(Options::Main::config_file, &argc,
                             (char ***) &argv, &args_used,
                             process_option, (void*) this))
    log_info("Falling back to compiled-in defaults.");

  return complete_initialization();
}


/*************************************************************************
  {{{ Instance_map::Iterator implementation.
*************************************************************************/

void Instance_map::Iterator::go_to_first()
{
  current_instance=0;
}


Instance *Instance_map::Iterator::next()
{
  if (current_instance < instance_map->hash.records)
    return (Instance *) hash_element(&instance_map->hash, current_instance++);

  return NULL;
}

/*************************************************************************
  }}}
*************************************************************************/


/**
  Create a new configuration section for mysqld-instance in the config file.

  SYNOPSIS
    create_instance_in_file()
    instance_name       mysqld-instance name
    options             options for the new mysqld-instance

  RETURN
    0     On success
    ER_CONF_FILE_DOES_NOT_EXIST     If config file does not exist
    ER_ACCESS_OPTION_FILE           If config file is not writable or some I/O
                                    error ocurred during writing configuration
*/

int create_instance_in_file(const LEX_STRING *instance_name,
                            const Named_value_arr *options)
{
  File cnf_file;

  if (my_access(Options::Main::config_file, W_OK))
  {
    log_error("Configuration file (%s) does not exist.",
              (const char *) Options::Main::config_file);
    return ER_CONF_FILE_DOES_NOT_EXIST;
  }

  cnf_file= my_open(Options::Main::config_file, O_WRONLY | O_APPEND, MYF(0));

  if (cnf_file <= 0)
  {
    log_error("Can not open configuration file (%s): %s.",
              (const char *) Options::Main::config_file,
              (const char *) strerror(errno));
    return ER_ACCESS_OPTION_FILE;
  }

  if (my_write(cnf_file, (byte*)NEWLINE, NEWLINE_LEN, MYF(MY_NABP)) ||
      my_write(cnf_file, (byte*)"[", 1, MYF(MY_NABP)) ||
      my_write(cnf_file, (byte*)instance_name->str, instance_name->length,
               MYF(MY_NABP)) ||
      my_write(cnf_file, (byte*)"]", 1,   MYF(MY_NABP)) ||
      my_write(cnf_file, (byte*)NEWLINE, NEWLINE_LEN, MYF(MY_NABP)))
  {
    log_error("Can not write to configuration file (%s): %s.",
              (const char *) Options::Main::config_file,
              (const char *) strerror(errno));
    my_close(cnf_file, MYF(0));
    return ER_ACCESS_OPTION_FILE;
  }

  for (int i= 0; options && i < options->get_size(); ++i)
  {
    char option_str[MAX_OPTION_STR_LEN];
    char *ptr;
    int option_str_len;
    Named_value option= options->get_element(i);

    ptr= strxnmov(option_str, MAX_OPTION_LEN + 1, option.get_name(), NullS);

    if (option.get_value()[0])
      ptr= strxnmov(ptr, MAX_OPTION_LEN + 2, "=", option.get_value(), NullS);

    option_str_len= ptr - option_str;

    if (my_write(cnf_file, (byte*)option_str, option_str_len, MYF(MY_NABP)) ||
        my_write(cnf_file, (byte*)NEWLINE, NEWLINE_LEN, MYF(MY_NABP)))
    {
      log_error("Can not write to configuration file (%s): %s.",
                (const char *) Options::Main::config_file,
                (const char *) strerror(errno));
      my_close(cnf_file, MYF(0));
      return ER_ACCESS_OPTION_FILE;
    }
  }

  my_close(cnf_file, MYF(0));

  return 0;
}