PHPTAL-NP-0.7.0/libs/Types/Ref.php

   1 <?php
   2 /* vim: set expandtab tabstop=4 shiftwidth=4: */
   3 //
   4 //  Copyright (c) 2003 Laurent Bedubourg
   5 //
   6 //  This library is free software; you can redistribute it and/or
   7 //  modify it under the terms of the GNU Lesser General Public
   8 //  License as published by the Free Software Foundation; either
   9 //  version 2.1 of the License, or (at your option) any later version.
  10 //
  11 //  This library is distributed in the hope that it will be useful,
  12 //  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 //  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 //  Lesser General Public License for more details.
  15 //
  16 //  You should have received a copy of the GNU Lesser General Public
  17 //  License along with this library; if not, write to the Free Software
  18 //  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19 //
  20 //  Authors: Laurent Bedubourg <laurent.bedubourg@free.fr>
  21 //
  22
  23 /**
  24  * Create a new Ref object referencing specified object or variable.
  25  *
  26  * Any modification of the source object modify the Refence content, any
  27  * modification of the reference obj modify the source object.
  28  *
  29  * The referenced object can be reached using the reference object using the
  30  * 'obj' property.
  31  *
  32  * <?php
  33  *
  34  * $a = new Foo();
  35  * $ref_a = Ref($a);
  36  *
  37  * $ref_a->obj->doBar();   // call doBar() on $a
  38  *
  39  * ?>
  40  *
  41  * @param mixed $obj -- the object or variable to reference.
  42  * @return Ref
  43  */
  44 function ref(&$obj)
  45 {
  46     return new Ref($obj);
  47 }
  48
  49 /**
  50  * Returns true if the object is a Ref object.
  51  *
  52  * @param mixed $obj -- any variable that must be tested.
  53  *
  54  * @return boolean
  55  */
  56 function is_ref($obj)
  57 {
  58     return is_object($obj) && get_class($obj) == "ref";
  59 }
  60
  61
  62 /**
  63  * Reference class.
  64  *
  65  * There's a lot to say about references in PHP. The main problem come from the
  66  * fact that until ZendEngine2, objects are copied if not referenced.
  67  *
  68  * This class helps keeping references to objects even while modifying arrays.
  69  *
  70  * Example :
  71  *
  72  * If an array stores objects, using array_values will copy its
  73  * elements.
  74  *
  75  * If an array stores Ref objects referencing real objects, array_values copy
  76  * Ref objects but these copies still reference the source object.
  77  *
  78  * Until ZendEngine2, it is safer to use Ref objects in stead of object
  79  * references.
  80  *
  81  * <?php
  82  *
  83  * $a = new Foo('bar');
  84  * $v = new Vector();
  85  * $v->push(Ref($a));
  86  *
  87  * ?>
  88  *
  89  * Important :
  90  *
  91  * This object will have no meaning in php 4.4 as PHP will then use references
  92  * everywhere objects are involved.
  93  *
  94  * @author Laurent Bedubourg <laurent.bedubourg@free.fr>
  95  */
  96 class Ref
  97 {
  98     /**
  99      * php reference to data.
 100      */
 101     var $obj;
 102
 103     /**
 104      * Reference constructor.
 105      *
 106      * Important:
 107      *
 108      * If $r is a reference, the new reference will just be a copy of the
 109      * parameter.
 110      *
 111      * A Ref cannot reference a Ref.
 112      *
 113      * @param mixed $r -- the object or data to reference.
 114      */
 115     function Ref(&$r)
 116     {
 117         if (is_ref($r)) {
 118             $this->obj =& $r->obj;
 119         } else {
 120             $this->obj =& $r;
 121         }
 122     }
 123
 124     /**
 125      * Retrieve the type or the referenced variable.
 126      *
 127      * @return string
 128      */
 129     function type()
 130     {
 131         return gettype($this->obj);
 132     }
 133
 134     /**
 135      * Return the class name of the referenced variable (if object).
 136      *
 137      * @return string (empty if not an object)
 138      */
 139     function getClassName()
 140     {
 141         return get_class($this->obj);
 142     }
 143 }
 144
 145 ?>