PHPTAL-NP-0.7.0/libs/Types/Code.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 // $id$
  23
  24 require_once "Types/OString.php";
  25 require_once "Types/OHash.php";
  26
  27 /**
  28  * Common php string that extract parameters from an associative array.
  29  *
  30  * This string is appended to the begin of the produced php function. It
  31  * takes function context argument and extract it in named variables.
  32  *
  33  * @access private
  34  */
  35 define('_TYPES_CODE_EXTRACT_CODE_CONTEXT_',
  36 '// BEGIN EXTRACT __context__
  37 if (is_array($__context__)) { extract($__context__); }
  38 if (is_object($__context__)) { extract($__context__->toHash()); }
  39 // END EXTRACT __context__
  40 ');
  41
  42 /**
  43  * Code class handle and evaluate php code.
  44  *
  45  * The aim of this class is to dynamically generate executable php code from
  46  * php string.
  47  *
  48  * This kind of object can be safely serialized as the code it represents is
  49  * stored in the _code member variable.
  50  *
  51  * When setting code to this object, a new anonymous function is created
  52  * waiting to be invoqued using the execute() method.
  53  *
  54  * As we can't know how many parameters this function should take, a 'context'
  55  * hashtable is used as only parameter. This hash  may contains any number
  56  * of arguments with var name compliant keys.
  57  *
  58  * Code object automatically append 'extract' code string to produced code.
  59  *
  60  * It's up to the code to assert parameters using 'isset()' php function.
  61  *
  62  *      <?php
  63  *      require_once "Types/Code.php";
  64  *
  65  *      $o_code = Code()
  66  *      $o_code->setCode('return $foo . $bar . $baz;');
  67  *      $res = $o_code->execute(
  68  *          'foo', 'foo value ',
  69  *          'baz', 'bar value ',
  70  *          'baz', 'baz value'
  71  *      );
  72  *
  73  *      // will print 'foo value bar value baz value'
  74  *      echo $res, end;
  75  *      ?>
  76  *
  77  * @author Laurent Bedubourg <laurent.bedubourg@free.fr>
  78  */
  79 class Code
  80 {
  81     var $_code;
  82     var $_function;
  83     var $_compiled = false;
  84
  85     /**
  86      * Construct a new code object.
  87      *
  88      * @param mixed $code (optional)
  89      *        php code string or object implementing toString method.
  90      */
  91     function Code($code=false)
  92     {
  93         $this->__construct($code);
  94     }
  95
  96     function __construct($code=false)
  97     {
  98         if (!$code) {
  99             return $this;
 100         }
 101         if (is_object($code) && get_class($code) == 'code') {
 102             $this->_code = $code->getCode();
 103         } else {
 104             $this->setCode(Types::toString($code));
 105         }
 106     }
 107
 108     /**
 109      * Execute code with specific context.
 110      *
 111      * @param  mixed ...
 112      *         The function execution context. This may be an associative
 113      *         array, an OHash object, a list of key/value pairs that will
 114      *         be transformed into an associative array
 115      *
 116      * @return mixed The execution result.
 117      */
 118     function &execute()
 119     {
 120         if (!$this->_compiled) {
 121             $err =& $this->compile();
 122             if (PEAR::isError($err)) {
 123                 return $err;
 124             }
 125         }
 126         $argv = func_get_args();
 127         $argc = func_num_args();
 128         switch ($argc) {
 129             case 1:
 130                 $context = $argv[0];
 131                 break;
 132             default:
 133                 $context = OHash::ArrayToHash($argv);
 134                 break;
 135         }
 136         $func = $this->_function;
 137         return $func($context);
 138     }
 139
 140     /**
 141      * Compile php code.
 142      *
 143      * This function may produce parse errors.
 144      *
 145      * @throws CodeError
 146      */
 147     function compile()
 148     {
 149         ob_start();
 150         $this->_function = create_function('$__context__', $this->_code);
 151         $ret = ob_get_contents();
 152         ob_end_clean();
 153
 154         if (!$this->_function) {
 155             return PEAR::raiseError($ret);
 156         }
 157
 158         $this->_compiled = true;
 159     }
 160
 161     /**
 162      * Set function code.
 163      *
 164      * @param  string $str
 165      *         The php code string
 166      */
 167     function setCode($str)
 168     {
 169         // add extract code to function code
 170         $str = _TYPES_CODE_EXTRACT_CODE_CONTEXT_ . $str;
 171         $this->_code = $str;
 172     }
 173
 174     /**
 175      * Retrieve code.
 176      *
 177      * @return string
 178      */
 179     function getCode()
 180     {
 181         return $this->_code;
 182     }
 183
 184     /**
 185      * On serialization, we store only code, not additional variables.
 186      *
 187      * @access private
 188      */
 189     function __sleep()
 190     {
 191         return array("_code");
 192     }
 193
 194     /**
 195      * Make a string representation of this object.
 196      *
 197      * @return string
 198      */
 199     function toString()
 200     {
 201         if ($this->_compiled) {
 202             return '<Code \''.$this->_function.'\'>';
 203         } else {
 204             return '<Code \'not compiled\'>';
 205         }
 206     }
 207 }
 208
 209 /**
 210  * Code compilation error.
 211  *
 212  * This error handles parse errors an other problems that may occurs while
 213  * compiling a php code.
 214  */
 215 class CodeError extends PEAR_Error
 216 {
 217 }
 218
 219 ?>