/registry/native.php

<?php

/**

 * SPF_Registry_Native

 * @package    spf 

 * @author     Simon Downes <simon@simondownes.co.uk>

 * @copyright  Copyright (c) 2007, Simon Downes 

 * @license    http://www.opensource.org/licenses/mit-license.php

 */



/**

 * Native driver for the registry.

 * Stores data in SPF_APP_DIR/registry.conf in the format 'var = value'.

 * One line per item, leading and trailing whitespace is trimmed.

 * Lines beginning with # are ignored. 

 *

 * @final

 * @package    spf 

 * @author     Simon Downes <simon@simondownes.co.uk>

 * @copyright  Copyright (c) 2007, Simon Downes

 * @license    http://www.opensource.org/licenses/mit-license.php

 */

final class SPF_Registry_Native extends SPF_Registry {

   

   // path and filename of the registry data file.

   private $data_file = '';

   

   // stores the initial contents of the data file.

   private $data_file_contents = array();

   

   // will be set to true if any of the items have their value modified.

   private $dirty = false;

   

   /**

    * Constructor.

    *

    * @return       void

    */

   public function __construct() {



      parent::__construct();

      

      $this->data_file = SPF_APP_DIR. '/registry.conf';

      

      if( !file_exists($this->data_file) )

         throw new SPF_Fatal_Exception("Registry Initialisation Error: Data file '{$this->data_file}' does not exist!");

         

      if( !is_writable($this->data_file) )

         throw new SPF_Fatal_Exception("Registry Initialisation Error: Data file '{$this->data_file}' is not writable!");

      

      $data = file($this->data_file);

      

      foreach( $data as $line ) {

         

         $line = trim($line);

         

         if( !$line || substr($line, 0, 1) == '#' ) {

            $this->data_file_contents[] = $line;

            continue;

         }

         

         $pos = strpos($line, '=');

         

         if( $pos === false ) {

            $k = $line;

            $v = '';

         }

         else {

            $k = trim(substr($line, 0, $pos));

            $v = trim(substr($line, $pos + 1));

         }

         

         $this->items[$k] = $v;

         

         $this->data_file_contents[] = "$k = $v";

         

      } // each $data

      

   } // __construct



   /**

    * Destructor.

    *

    * @return       void

    */

   public function __destruct() {

      

      // ensure any changes are written to the data file

      $this->write_config_file();

      

      parent::__destruct();

      

   } // __destruct



   /**

    * Determines if a the specified variable exists in the registry.

    *

    * @param   string    $var_name   the name of the variable to look for.

    * @return  boolean

    */

   public function exists( $var_name ) {



      return array_key_exists($var_name, $this->items);



   } // exists



   /**

    * Retrieves the value of a variable from the registry.

    *

    * @param   string    $var_name   the name of the variable.

    * @param   mixed     $default    the default value to return if the variable doesn't exist.

    * @return  mixed     the value from the registry or the specified default value if the variable doesn't exist.

    */

   public function get( $var_name, $default = '' ) {



      return ( $this->exists($var_name) ) ? $this->items[$var_name] : $default;



   } // get



   /**

    * Returns the entire contents of the registry in an array.

    *

    * @return  array     all the entries in the registry.

    */

   public function get_all() {

      

      return $this->items;



   } // get_all



   /**

    * Sets the value of variable in the registry.

    *

    * @param   string    $var_name   the name of the variable.

    * @param   mixed     $val        the value of the variable.

    * @return  boolean   true if the variable was stored successfully; false otherwise.

    */

   public function set( $var_name, $val ) {

      

      if( !$var_name )

         return false;

      

      $this->items[$var_name] = $val;

      

      $this->dirty = true;

      

      return true;



   } // set

   

   /**

    * Removes a variable from the registry.

    *

    * @param   string    $var_name   the name of the variable.

    * @return  boolean   true if the variable was removed successfully; false otherwise.

    */

   public function delete( $var_name ) {



      unset($this->items[$var_name]);

      

      $this->dirty = true;

      

      return true;



   } // delete

   

   /**

    * Removes a variable from the registry.

    *

    * @param   string    $var_name   the name of the variable.

    * @return  boolean   true if the variable was removed successfully; false otherwise.

    */

   public function write_config_file() {

      

      if( !$this->dirty )

         return true;

      

      $file = new SPF_File($this->data_file, SPF_File::MODE_WRITE);

      

      $file->truncate();

      

      // temp copy of data so we can unset items as they are written to the file

      $items = $this->items;

      

      foreach( $this->data_file_contents as $line ) {

         

         if( !$line || substr($line, 0, 1) == '#' ) {

            $file->write_line($line);

            continue;

         }

         

         // find the key for this item

         $pos = strpos($line, '=');

         $k = ($pos === false) ? $line : trim(substr($line, 0, $pos));

         

         // if key exists then output current value

         if( isset($items[$k]) ) {

            $file->write_line("$k = {$items[$k]}");

            unset($items[$k]);

         }

         

      }

      

      // items still remaining the the array are new items and should be appended to the end of the file

      foreach( $items as $k => $v ) {

         $file->write_line("$k = $v");

      }

      

      $this->dirty = false;

      

   }

   

} // SPF_Registry_Native



?>