system/libraries/Migration.php

   1 <?php defined('BASEPATH') OR exit('No direct script access allowed');
   2 /**
   3  * CodeIgniter
   4  *
   5  * An open source application development framework for PHP 5.1.6 or newer
   6  *
   7  * @package             CodeIgniter
   8  * @author              EllisLab Dev Team
   9  * @copyright   Copyright (c) 2006 - 2012, EllisLab, Inc.
  10  * @license             http://codeigniter.com/user_guide/license.html
  11  * @link                http://codeigniter.com
  12  * @since               Version 1.0
  13  * @filesource
  14  */
  15
  16 // ------------------------------------------------------------------------
  17
  18 /**
  19  * Migration Class
  20  *
  21  * All migrations should implement this, forces up() and down() and gives
  22  * access to the CI super-global.
  23  *
  24  * @package             CodeIgniter
  25  * @subpackage  Libraries
  26  * @category    Libraries
  27  * @author              Reactor Engineers
  28  * @link
  29  */
  30 class CI_Migration {
  31
  32         protected $_migration_enabled = FALSE;
  33         protected $_migration_path = NULL;
  34         protected $_migration_version = 0;
  35
  36         protected $_error_string = '';
  37
  38         public function __construct($config = array())
  39         {
  40                 # Only run this constructor on main library load
  41                 if (get_parent_class($this) !== FALSE)
  42                 {
  43                         return;
  44                 }
  45
  46                 foreach ($config as $key => $val)
  47                 {
  48                         $this->{'_' . $key} = $val;
  49                 }
  50
  51                 log_message('debug', 'Migrations class initialized');
  52
  53                 // Are they trying to use migrations while it is disabled?
  54                 if ($this->_migration_enabled !== TRUE)
  55                 {
  56                         show_error('Migrations has been loaded but is disabled or set up incorrectly.');
  57                 }
  58
  59                 // If not set, set it
  60                 $this->_migration_path == '' AND $this->_migration_path = APPPATH . 'migrations/';
  61
  62                 // Add trailing slash if not set
  63                 $this->_migration_path = rtrim($this->_migration_path, '/').'/';
  64
  65                 // Load migration language
  66                 $this->lang->load('migration');
  67
  68                 // They'll probably be using dbforge
  69                 $this->load->dbforge();
  70
  71                 // If the migrations table is missing, make it
  72                 if ( ! $this->db->table_exists('migrations'))
  73                 {
  74                         $this->dbforge->add_field(array(
  75                                 'version' => array('type' => 'INT', 'constraint' => 3),
  76                         ));
  77
  78                         $this->dbforge->create_table('migrations', TRUE);
  79
  80                         $this->db->insert('migrations', array('version' => 0));
  81                 }
  82         }
  83
  84         // --------------------------------------------------------------------
  85
  86         /**
  87          * Migrate to a schema version
  88          *
  89          * Calls each migration step required to get to the schema version of
  90          * choice
  91          *
  92          * @param       int     Target schema version
  93          * @return      mixed   TRUE if already latest, FALSE if failed, int if upgraded
  94          */
  95         public function version($target_version)
  96         {
  97                 $start = $current_version = $this->_get_version();
  98                 $stop = $target_version;
  99
 100                 if ($target_version > $current_version)
 101                 {
 102                         // Moving Up
 103                         ++$start;
 104                         ++$stop;
 105                         $step = 1;
 106                 }
 107                 else
 108                 {
 109                         // Moving Down
 110                         $step = -1;
 111                 }
 112
 113                 $method = ($step === 1) ? 'up' : 'down';
 114                 $migrations = array();
 115
 116                 // We now prepare to actually DO the migrations
 117                 // But first let's make sure that everything is the way it should be
 118                 for ($i = $start; $i != $stop; $i += $step)
 119                 {
 120                         $f = glob(sprintf($this->_migration_path . '%03d_*.php', $i));
 121
 122                         // Only one migration per step is permitted
 123                         if (count($f) > 1)
 124                         {
 125                                 $this->_error_string = sprintf($this->lang->line('migration_multiple_version'), $i);
 126                                 return FALSE;
 127                         }
 128
 129                         // Migration step not found
 130                         if (count($f) == 0)
 131                         {
 132                                 // If trying to migrate up to a version greater than the last
 133                                 // existing one, migrate to the last one.
 134                                 if ($step == 1)
 135                                 {
 136                                         break;
 137                                 }
 138
 139                                 // If trying to migrate down but we're missing a step,
 140                                 // something must definitely be wrong.
 141                                 $this->_error_string = sprintf($this->lang->line('migration_not_found'), $i);
 142                                 return FALSE;
 143                         }
 144
 145                         $file = basename($f[0]);
 146                         $name = basename($f[0], '.php');
 147
 148                         // Filename validations
 149                         if (preg_match('/^\d{3}_(\w+)$/', $name, $match))
 150                         {
 151                                 $match[1] = strtolower($match[1]);
 152
 153                                 // Cannot repeat a migration at different steps
 154                                 if (in_array($match[1], $migrations))
 155                                 {
 156                                         $this->_error_string = sprintf($this->lang->line('migration_multiple_version'), $match[1]);
 157                                         return FALSE;
 158                                 }
 159
 160                                 include $f[0];
 161                                 $class = 'Migration_' . ucfirst($match[1]);
 162
 163                                 if ( ! class_exists($class))
 164                                 {
 165                                         $this->_error_string = sprintf($this->lang->line('migration_class_doesnt_exist'), $class);
 166                                         return FALSE;
 167                                 }
 168
 169                                 if ( ! is_callable(array($class, $method)))
 170                                 {
 171                                         $this->_error_string = sprintf($this->lang->line('migration_missing_'.$method.'_method'), $class);
 172                                         return FALSE;
 173                                 }
 174
 175                                 $migrations[] = $match[1];
 176                         }
 177                         else
 178                         {
 179                                 $this->_error_string = sprintf($this->lang->line('migration_invalid_filename'), $file);
 180                                 return FALSE;
 181                         }
 182                 }
 183
 184                 log_message('debug', 'Current migration: ' . $current_version);
 185
 186                 $version = $i + ($step == 1 ? -1 : 0);
 187
 188                 // If there is nothing to do so quit
 189                 if ($migrations === array())
 190                 {
 191                         return TRUE;
 192                 }
 193
 194                 log_message('debug', 'Migrating from ' . $method . ' to version ' . $version);
 195
 196                 // Loop through the migrations
 197                 foreach ($migrations AS $migration)
 198                 {
 199                         // Run the migration class
 200                         $class = 'Migration_' . ucfirst(strtolower($migration));
 201                         call_user_func(array(new $class, $method));
 202
 203                         $current_version += $step;
 204                         $this->_update_version($current_version);
 205                 }
 206
 207                 log_message('debug', 'Finished migrating to '.$current_version);
 208
 209                 return $current_version;
 210         }
 211
 212         // --------------------------------------------------------------------
 213
 214         /**
 215          * Set's the schema to the latest migration
 216          *
 217          * @return      mixed   true if already latest, false if failed, int if upgraded
 218          */
 219         public function latest()
 220         {
 221                 if ( ! $migrations = $this->find_migrations())
 222                 {
 223                         $this->_error_string = $this->line->lang('migration_none_found');
 224                         return false;
 225                 }
 226
 227                 $last_migration = basename(end($migrations));
 228
 229                 // Calculate the last migration step from existing migration
 230                 // filenames and procceed to the standard version migration
 231                 return $this->version((int) substr($last_migration, 0, 3));
 232         }
 233
 234         // --------------------------------------------------------------------
 235
 236         /**
 237          * Set's the schema to the migration version set in config
 238          *
 239          * @return      mixed   true if already current, false if failed, int if upgraded
 240          */
 241         public function current()
 242         {
 243                 return $this->version($this->_migration_version);
 244         }
 245
 246         // --------------------------------------------------------------------
 247
 248         /**
 249          * Error string
 250          *
 251          * @return      string  Error message returned as a string
 252          */
 253         public function error_string()
 254         {
 255                 return $this->_error_string;
 256         }
 257
 258         // --------------------------------------------------------------------
 259
 260         /**
 261          * Set's the schema to the latest migration
 262          *
 263          * @return      mixed   true if already latest, false if failed, int if upgraded
 264          */
 265         protected function find_migrations()
 266         {
 267                 // Load all *_*.php files in the migrations path
 268                 $files = glob($this->_migration_path . '*_*.php');
 269                 $file_count = count($files);
 270
 271                 for ($i = 0; $i < $file_count; $i++)
 272                 {
 273                         // Mark wrongly formatted files as false for later filtering
 274                         $name = basename($files[$i], '.php');
 275                         if ( ! preg_match('/^\d{3}_(\w+)$/', $name))
 276                         {
 277                                 $files[$i] = FALSE;
 278                         }
 279                 }
 280
 281                 sort($files);
 282                 return $files;
 283         }
 284
 285         // --------------------------------------------------------------------
 286
 287         /**
 288          * Retrieves current schema version
 289          *
 290          * @return      int     Current Migration
 291          */
 292         protected function _get_version()
 293         {
 294                 $row = $this->db->get('migrations')->row();
 295                 return $row ? $row->version : 0;
 296         }
 297
 298         // --------------------------------------------------------------------
 299
 300         /**
 301          * Stores the current schema version
 302          *
 303          * @param       int     Migration reached
 304          * @return      bool
 305          */
 306         protected function _update_version($migrations)
 307         {
 308                 return $this->db->update('migrations', array(
 309                         'version' => $migrations
 310                 ));
 311         }
 312
 313         // --------------------------------------------------------------------
 314
 315         /**
 316          * Enable the use of CI super-global
 317          *
 318          * @param       mixed   $var
 319          * @return      mixed
 320          */
 321         public function __get($var)
 322         {
 323                 return get_instance()->$var;
 324         }
 325 }
 326
 327 /* End of file Migration.php */
 328 /* Location: ./system/libraries/Migration.php */