PHPTAL-NP-0.7.0/libs/PHPTAL/Context.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 // What are Context and Resolvers
  25 // ==============================
  26 //
  27 // In phptal, variables and methods are referenced by path without distinction,
  28 // also, arrays and hashtable elements are accessed using a path like
  29 // myarray/10 to reach the 11's element of myarray or myhash/mykey to
  30 // reach the value of mykey in myhash.
  31 //
  32 // This allow things like 'myobject/mymethod/10/othermethod' which is usefull
  33 // in templates.
  34 //
  35 // The Context is an array containing all template variables.
  36 // When asked to reach a path, it look for the variable type of the first path
  37 // element and generate a resolver matching the variable type.
  38 // Then this resolver is asked to resolve the rest of the path, etc... up to
  39 // the final path element.
  40 //
  41 // Resolver knows how to handle a given path relatively to the object they
  42 // handle.
  43 //
  44 // For instance, an array resolver can handle access to its array elements
  45 // given a key (string) or the element id (int).
  46 //
  47 // The array resolver also bring an array method : count which return the
  48 // number of elements in the array.
  49 //
  50 // Note
  51 // ----
  52 //
  53 // If a name conflict occurs between an object's variable and one of its
  54 // methods, the variable is return in stead of the method.
  55 //
  56
  57 /**
  58  * Template context handler.
  59  *
  60  * This object produce a translation between variables passed to the template
  61  * and regular template pathes.
  62  *
  63  * @author Laurent Bedubourg <laurent.bedubourg@free.fr>
  64  */
  65 class PHPTAL_Context
  66 {
  67     var $_array = array();
  68     var $_errorRaised = false;
  69
  70     /**
  71      * Context constructor.
  72      *
  73      * @param hashtable $hash (opt)
  74      */
  75     function PHPTAL_Context($hash=array())
  76     {
  77         $this->_array = $hash;
  78     }
  79
  80     /**
  81      * Set a value by reference.
  82      *
  83      * @param string $path  -- Variable path
  84      * @param mixed  $value -- Reference to variable.
  85      */
  86     function setRef($path, &$value)
  87     {
  88         $this->remove($path);
  89         $this->_array[$path] =& $value;
  90     }
  91
  92     /**
  93      * Set a context variable.
  94      *
  95      * @param string $path  -- Variable path
  96      * @param mixed  $value -- Value
  97      */
  98     function set($path, $value)
  99     {
 100         $this->remove($path);
 101         $this->_array[$path] = $value;
 102     }
 103
 104     /**
 105      * Remove a context variable.
 106      *
 107      * @param string $path -- Context path
 108      */
 109     function remove($path)
 110     {
 111         if (array_key_exists($path, $this->_array)) {
 112             unset($this->_array[$path]);
 113         }
 114     }
 115
 116     /**
 117      * Test if the context can resolve specified path.
 118      *
 119      * @param string $path
 120      *        Path to a context resource.
 121      *
 122      * @return boolean
 123      */
 124     function has($path)
 125     {
 126         if (array_key_exists($path, $this->_array)) {
 127             return true;
 128         }
 129         $resp =& PHPTAL_ArrayResolver::get($this->_array, $path);
 130         if (PEAR::isError($resp)) {
 131             return false;
 132         } else if ($resp === null) {
 133             return false;
 134         }
 135         return true;
 136     }
 137
 138     /**
 139      * Return the context associative object.
 140      */
 141     function &getHash()
 142     {
 143         return $this->_array;
 144     }
 145
 146     /**
 147      * Retrieve specified context resource.
 148      *
 149      * @param string $path
 150      *        Path to a context resource.
 151      *
 152      * @return mixed
 153      * @throws NameError
 154      */
 155     function &get($path)
 156     {
 157         if (array_key_exists($path, $this->_array)) {
 158             return $this->_array[$path];
 159         }
 160         $resp =& PHPTAL_ArrayResolver::get($this->_array, $path);
 161         if (PEAR::isError($resp)) {
 162             $this->_errorRaised = $resp;
 163         } else if ($resp === null) {
 164             $this->_errorRaised = true;
 165         }
 166         return $resp;
 167     }
 168
 169     /**
 170      * Retrieve specified context resouce as a string object
 171      *
 172      * @param string $path
 173      *        Path to a context resource.
 174      *
 175      * @return string
 176      */
 177     function &getToString($path)
 178     {
 179         $o = $this->get($path);
 180         if (is_object($o) && method_exists($o, "toString")) {
 181             return $o->toString();
 182         }
 183         if (is_object($o) || is_array($o)) {
 184             ob_start();
 185             print_r($o); // var_dump($o);
 186             $res = ob_get_contents();
 187             ob_end_clean();
 188             return $res;
 189         }
 190         return $o;
 191     }
 192
 193     /**
 194      * Tells if an error was raised by this context accessing an unknown path.
 195      *
 196      * @return boolean
 197      */
 198     function errorRaised()
 199     {
 200         $r = $this->_errorRaised;
 201         $this->_errorRaised = false;
 202         return $r;
 203     }
 204
 205     /**
 206      * Clean error handler.
 207      */
 208     function cleanError()
 209     {
 210         $this->_errorRaised = false;
 211     }
 212 }
 213
 214 /**
 215  * Object resolver.
 216  *
 217  * Resolver pathes relatives to object.
 218  *
 219  * @access private
 220  * @author Laurent Bedubourg <laurent.bedubourg@free.fr>
 221  */
 222 class PHPTAL_ObjectResolver
 223 {
 224     function &get(&$obj, $subpath)
 225     {
 226         list($first, $next) = PHPTAL_path_explode($subpath);
 227
 228         if (method_exists($obj, $first)) {
 229             // reference to a variable of the handled object
 230             $value =& $obj->$first();
 231         } elseif (array_key_exists($first, $obj)) {
 232             // reference to an object variable
 233             $value =& $obj->$first;
 234         } elseif (is_a($obj, 'OHash') && $obj->containsKey($first)) {
 235             return $obj->get($first);
 236         } elseif (is_a($obj, 'OArray') && preg_match('/^[0-9]+$/', $first)) {
 237             return $obj->get((int)$first);
 238         } else {
 239             $err = new NameError($subpath . " not found");
 240             return $err;
 241         }
 242         // more to resolve in value
 243         if ($next) {
 244             return PHPTAL_resolve($next, $value, $obj);
 245         }
 246         return $value;
 247     }
 248 }
 249
 250
 251 /**
 252  * Array resolver.
 253  *
 254  * Resolve pathes relative to arrays and hashtables.
 255  *
 256  * @author Laurent Bedubourg <laurent.bedubourg@free.fr>
 257  */
 258 class PHPTAL_ArrayResolver
 259 {
 260     function &get(&$array, $subpath)
 261     {
 262         list($first, $next) = PHPTAL_path_explode($subpath);
 263
 264         if ($first == "length" && !$next && !array_key_exists("length", $array)) {
 265             return count($array);
 266         }
 267
 268         if ($next === false) {
 269             if ($first == 'count') { return count($array); }
 270             if ($first == 'keys')  { return array_keys($array); }
 271             if ($first == 'values'){ return array_values($array); }
 272             if (!array_key_exists($first, $array)) {
 273                 $err = new NameError("(ArrayResolver) Context does not contains key '$first'");
 274                 return $err;
 275             }
 276             return $array[$first];
 277         }
 278
 279         if (!array_key_exists($first, $array)) {
 280             $err = new NameError("(ArrayResolver) Context does not contains key '$first'");
 281             return $err;
 282         }
 283         $temp =& $array[$first];
 284         if ($temp) {
 285             return PHPTAL_resolve($next, $temp, $array);
 286         }
 287     }
 288 }
 289
 290
 291 /**
 292  * String resolver.
 293  *
 294  * Add method to string type.
 295  */
 296 class PHPTAL_StringResolver
 297 {
 298     function get(&$str, $subpath)
 299     {
 300         list($first, $next) = PHPTAL_path_explode($subpath);
 301         if ($next) {
 302             $err = new TypeError("string methods have no sub path (string.$subpath)");
 303             return $err;
 304         }
 305         if ($first == "len") {
 306             return strlen($str);
 307         }
 308         $err = new NameError("string type has no method named '$first'");
 309         return $err;
 310     }
 311 };
 312
 313 /**
 314  * Retrieve a resolver given a value and a parent.
 315  */
 316 function &PHPTAL_resolve($path, &$value, &$parent)
 317 {
 318     if (is_array($value))  return PHPTAL_ArrayResolver::get($value, $path);
 319     if (is_object($value)) return PHPTAL_ObjectResolver::get($value, $path);
 320     if (is_string($value)) return PHPTAL_StringResolver::get($value, $path);
 321     $err = new TypeError("unable to find adequate resolver for '".gettype($value)."' remaining path is '$path'");
 322     return $err;
 323 }
 324
 325 /**
 326  * Shift the first elemetn of a phptal path.
 327  *
 328  * Returns an array containing the first element of the path and the rest of
 329  * the path.
 330  */
 331 function PHPTAL_path_explode($path)
 332 {
 333     if (preg_match('|^(.*?)\/(.*?)$|', $path, $match)) {
 334         array_shift($match);
 335         return $match;
 336     } else {
 337         return array($path, false);
 338     }
 339
 340     $pos = strpos($path,".");
 341     if ($pos !== false) {
 342         $first = substr($path, 0, $pos);
 343         $next  = substr($path, $pos+1);
 344         return array($first, $next);
 345     }
 346     return array($path, false);
 347 }
 348
 349 ?>