theme.inc 93.3 KB
Newer Older
Dries's avatar
 
Dries committed
1
<?php
2
// $Id$
Dries's avatar
 
Dries committed
3

4
/**
Dries's avatar
 
Dries committed
5
 * @file
6
 * The theme system, which controls the output of Drupal.
Dries's avatar
 
Dries committed
7 8 9 10
 *
 * The theme system allows for nearly all output of the Drupal system to be
 * customized by user themes.
 */
Dries's avatar
 
Dries committed
11

12
/**
13 14 15 16 17
 * @name Content markers
 * @{
 * Markers used by theme_mark() and node_mark() to designate content.
 * @see theme_mark(), node_mark()
 */
18 19 20 21 22 23 24 25 26 27 28 29 30 31

/**
 * Mark content as read.
 */
define('MARK_READ', 0);

/**
 * Mark content as being new.
 */
define('MARK_NEW', 1);

/**
 * Mark content as being updated.
 */
32
define('MARK_UPDATED', 2);
33

34 35 36 37
/**
 * @} End of "Content markers".
 */

38 39 40 41
/**
 * Determines if a theme is available to use.
 *
 * @param $theme
42 43
 *   Either the name of a theme or a full theme object.
 *
44 45 46 47 48
 * @return
 *   Boolean TRUE if the theme is enabled or is the site administration theme;
 *   FALSE otherwise.
 */
function drupal_theme_access($theme) {
49 50 51 52 53 54 55 56 57 58 59 60 61 62 63
  if (is_object($theme)) {
    return _drupal_theme_access($theme);
  }
  else {
    $themes = list_themes();
    return isset($themes[$theme]) && _drupal_theme_access($themes[$theme]);
  }
}

/**
 * Helper function for determining access to a theme.
 *
 * @see drupal_theme_access()
 */
function _drupal_theme_access($theme) {
64 65 66 67
  $admin_theme = variable_get('admin_theme');
  return !empty($theme->status) || ($admin_theme && $theme->name == $admin_theme);
}

Dries's avatar
 
Dries committed
68
/**
Dries's avatar
 
Dries committed
69
 * Initialize the theme system by loading the theme.
Dries's avatar
 
Dries committed
70
 */
71
function drupal_theme_initialize() {
72
  global $theme, $user, $theme_key;
73 74 75 76 77

  // If $theme is already set, assume the others are set, too, and do nothing
  if (isset($theme)) {
    return;
  }
Dries's avatar
 
Dries committed
78

79
  drupal_bootstrap(DRUPAL_BOOTSTRAP_DATABASE);
Dries's avatar
 
Dries committed
80 81
  $themes = list_themes();

82
  // Only select the user selected theme if it is available in the
83
  // list of themes that can be accessed.
84
  $theme = !empty($user->theme) && drupal_theme_access($user->theme) ? $user->theme : variable_get('theme_default', 'bartik');
Dries's avatar
 
Dries committed
85

86 87
  // Allow modules to override the theme. Validation has already been performed
  // inside menu_get_custom_theme(), so we do not need to check it again here.
88
  $custom_theme = menu_get_custom_theme();
89
  $theme = !empty($custom_theme) ? $custom_theme : $theme;
Dries's avatar
 
Dries committed
90 91 92 93

  // Store the identifier for retrieving theme settings with.
  $theme_key = $theme;

94 95 96 97
  // Find all our ancestor themes and put them in an array.
  $base_theme = array();
  $ancestor = $theme;
  while ($ancestor && isset($themes[$ancestor]->base_theme)) {
98 99
    $base_theme[] = $new_base_theme = $themes[$themes[$ancestor]->base_theme];
    $ancestor = $themes[$ancestor]->base_theme;
100
  }
101
  _drupal_theme_initialize($themes[$theme], array_reverse($base_theme));
102 103 104

  // Themes can have alter functions, so reset the drupal_alter() cache.
  drupal_static_reset('drupal_alter');
105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128
}

/**
 * Initialize the theme system given already loaded information. This
 * function is useful to initialize a theme when no database is present.
 *
 * @param $theme
 *   An object with the following information:
 *     filename
 *       The .info file for this theme. The 'path' to
 *       the theme will be in this file's directory. (Required)
 *     owner
 *       The path to the .theme file or the .engine file to load for
 *       the theme. (Required)
 *     stylesheet
 *       The primary stylesheet for the theme. (Optional)
 *     engine
 *       The name of theme engine to use. (Optional)
 * @param $base_theme
 *    An optional array of objects that represent the 'base theme' if the
 *    theme is meant to be derivative of another theme. It requires
 *    the same information as the $theme object. It should be in
 *    'oldest first' order, meaning the top level of the chain will
 *    be first.
129 130
 * @param $registry_callback
 *   The callback to invoke to set the theme registry.
131
 */
132
function _drupal_theme_initialize($theme, $base_theme = array(), $registry_callback = '_theme_load_registry') {
133 134 135 136 137 138
  global $theme_info, $base_theme_info, $theme_engine, $theme_path;
  $theme_info = $theme;
  $base_theme_info = $base_theme;

  $theme_path = dirname($theme->filename);

139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154
  // Prepare stylesheets from this theme as well as all ancestor themes.
  // We work it this way so that we can have child themes override parent
  // theme stylesheets easily.
  $final_stylesheets = array();

  // Grab stylesheets from base theme
  foreach ($base_theme as $base) {
    if (!empty($base->stylesheets)) {
      foreach ($base->stylesheets as $media => $stylesheets) {
        foreach ($stylesheets as $name => $stylesheet) {
          $final_stylesheets[$media][$name] = $stylesheet;
        }
      }
    }
  }

155 156 157
  // Add stylesheets used by this theme.
  if (!empty($theme->stylesheets)) {
    foreach ($theme->stylesheets as $media => $stylesheets) {
158 159 160 161 162 163 164 165 166
      foreach ($stylesheets as $name => $stylesheet) {
        $final_stylesheets[$media][$name] = $stylesheet;
      }
    }
  }

  // And now add the stylesheets properly
  foreach ($final_stylesheets as $media => $stylesheets) {
    foreach ($stylesheets as $stylesheet) {
167
      drupal_add_css($stylesheet, array('weight' => CSS_THEME, 'media' => $media));
168 169 170 171 172 173 174 175 176 177 178
    }
  }

  // Do basically the same as the above for scripts
  $final_scripts = array();

  // Grab scripts from base theme
  foreach ($base_theme as $base) {
    if (!empty($base->scripts)) {
      foreach ($base->scripts as $name => $script) {
        $final_scripts[$name] = $script;
179
      }
Dries's avatar
 
Dries committed
180 181
    }
  }
182

183 184
  // Add scripts used by this theme.
  if (!empty($theme->scripts)) {
185 186
    foreach ($theme->scripts as $name => $script) {
      $final_scripts[$name] = $script;
187 188 189
    }
  }

190 191
  // Add scripts used by this theme.
  foreach ($final_scripts as $script) {
192
    drupal_add_js($script, array('weight' => JS_THEME));
193 194
  }

195 196 197 198 199
  $theme_engine = NULL;

  // Initialize the theme.
  if (isset($theme->engine)) {
    // Include the engine.
200
    include_once DRUPAL_ROOT . '/' . $theme->owner;
201 202

    $theme_engine = $theme->engine;
203
    if (function_exists($theme_engine . '_init')) {
204
      foreach ($base_theme as $base) {
205
        call_user_func($theme_engine . '_init', $base);
206
      }
207
      call_user_func($theme_engine . '_init', $theme);
208 209 210 211 212 213 214
    }
  }
  else {
    // include non-engine theme files
    foreach ($base_theme as $base) {
      // Include the theme file or the engine.
      if (!empty($base->owner)) {
215
        include_once DRUPAL_ROOT . '/' . $base->owner;
216 217 218 219
      }
    }
    // and our theme gets one too.
    if (!empty($theme->owner)) {
220
      include_once DRUPAL_ROOT . '/' . $theme->owner;
Dries's avatar
 
Dries committed
221 222
    }
  }
223

224
  if (function_exists($registry_callback)) {
225 226
    $registry_callback($theme, $base_theme, $theme_engine);
  }
Dries's avatar
 
Dries committed
227 228
}

229
/**
230
 * Get the theme registry.
231
 *
232 233
 * @return
 *   The theme registry array if it has been stored in memory, NULL otherwise.
234
 */
235 236
function theme_get_registry() {
  return _theme_set_registry();
237 238 239 240
}

/**
 * Store the theme registry in memory.
241
 *
242 243
 * @param $registry
 *   A registry array as returned by _theme_build_registry()
244
 *
245
 * @return
246
 *   The theme registry array stored in memory
247
 */
248 249
function _theme_set_registry($registry = NULL) {
  static $theme_registry = NULL;
250

251 252 253
  if (isset($registry)) {
    $theme_registry = $registry;
  }
254

255
  return $theme_registry;
256 257 258
}

/**
259
 * Get the theme_registry cache from the database; if it doesn't exist, build it.
260 261
 *
 * @param $theme
262
 *   The loaded $theme object as returned by list_themes().
263 264 265 266 267
 * @param $base_theme
 *   An array of loaded $theme objects representing the ancestor themes in
 *   oldest first order.
 * @param theme_engine
 *   The name of the theme engine.
268
 */
269 270 271
function _theme_load_registry($theme, $base_theme = NULL, $theme_engine = NULL) {
  // Check the theme registry cache; if it exists, use it.
  $cache = cache_get("theme_registry:$theme->name", 'cache');
272
  if (isset($cache->data)) {
273
    $registry = $cache->data;
274
    _theme_set_registry($registry);
275 276
  }
  else {
277 278
    // If not, build one and cache it.
    $registry = _theme_build_registry($theme, $base_theme, $theme_engine);
279
   // Only persist this registry if all modules are loaded. This assures a
280
   // complete set of theme hooks.
281
    if (module_load_all(NULL)) {
282 283 284
      _theme_save_registry($theme, $registry);
      _theme_set_registry($registry);
    }
285 286 287 288 289 290 291
  }
}

/**
 * Write the theme_registry cache into the database.
 */
function _theme_save_registry($theme, $registry) {
292
  cache_set("theme_registry:$theme->name", $registry);
293 294 295 296 297 298 299
}

/**
 * Force the system to rebuild the theme registry; this should be called
 * when modules are added to the system, or when a dynamic system needs
 * to add more theme hooks.
 */
300
function drupal_theme_rebuild() {
301 302 303 304
  cache_clear_all('theme_registry', 'cache', TRUE);
}

/**
305
 * Process a single implementation of hook_theme().
306
 *
307 308 309 310 311 312 313 314 315 316 317 318 319 320 321
 * @param $cache
 *   The theme registry that will eventually be cached; It is an associative
 *   array keyed by theme hooks, whose values are associative arrays describing
 *   the hook:
 *   - 'type': The passed in $type.
 *   - 'theme path': The passed in $path.
 *   - 'function': The name of the function generating output for this theme
 *     hook. Either defined explicitly in hook_theme() or, if neither 'function'
 *     nor 'template' is defined, then the default theme function name is used.
 *     The default theme function name is the theme hook prefixed by either
 *     'theme_' for modules or '$name_' for everything else. If 'function' is
 *     defined, 'template' is not used.
 *   - 'template': The filename of the template generating output for this
 *     theme hook. The template is in the directory defined by the 'path' key of
 *     hook_theme() or defaults to $path.
322 323
 *   - 'variables': The variables for this theme hook as defined in
 *     hook_theme(). If there is more than one implementation and 'variables' is
324
 *     not specified in a later one, then the previous definition is kept.
325 326 327 328
 *   - 'render element': The renderable element for this theme hook as defined
 *     in hook_theme(). If there is more than one implementation and
 *     'render element' is not specified in a later one, then the previous
 *     definition is kept.
329
 *   - 'preprocess functions': See theme() for detailed documentation.
330
 *   - 'process functions': See theme() for detailed documentation.
331 332 333 334 335 336 337 338 339 340 341 342 343 344 345
 * @param $name
 *   The name of the module, theme engine, base theme engine, theme or base
 *   theme implementing hook_theme().
 * @param $type
 *   One of 'module', 'theme_engine', 'base_theme_engine', 'theme', or
 *   'base_theme'. Unlike regular hooks that can only be implemented by modules,
 *   each of these can implement hook_theme(). _theme_process_registry() is
 *   called in aforementioned order and new entries override older ones. For
 *   example, if a theme hook is both defined by a module and a theme, then the
 *   definition in the theme will be used.
 * @param $theme
 *   The loaded $theme object as returned from list_themes().
 * @param $path
 *   The directory where $name is. For example, modules/system or
 *   themes/garland.
346
 *
347 348 349 350
 * @see theme()
 * @see _theme_process_registry()
 * @see hook_theme()
 * @see list_themes()
351
 */
352
function _theme_process_registry(&$cache, $name, $type, $theme, $path) {
353
  $result = array();
354
  $function = $name . '_theme';
355

356
  // Processor functions work in two distinct phases with the process
357
  // functions always being executed after the preprocess functions.
358
  $variable_process_phases = array(
359 360 361 362
    'preprocess functions' => 'preprocess',
    'process functions'    => 'process',
  );

363
  if (function_exists($function)) {
364
    $result = $function($cache, $type, $theme, $path);
365 366
    foreach ($result as $hook => $info) {
      $result[$hook]['type'] = $type;
367
      $result[$hook]['theme path'] = $path;
368 369
      // if function and file are left out, default to standard naming
      // conventions.
370
      if (!isset($info['template']) && !isset($info['function'])) {
371
        $result[$hook]['function'] = ($type == 'module' ? 'theme_' : $name . '_') . $hook;
372
      }
373 374 375 376 377
      // If a path is set in the info, use what was set. Otherwise use the
      // default path. This is mostly so system.module can declare theme
      // functions on behalf of core .include files.
      // All files are included to be safe. Conditionally included
      // files can prevent them from getting registered.
378 379
      if (isset($cache[$hook]['includes'])) {
        $result[$hook]['includes'] = $cache[$hook]['includes'];
380
      }
381 382 383 384 385
      if (isset($info['file'])) {
        $include_file = isset($info['path']) ? $info['path'] : $path;
        $include_file .= '/' . $info['file'];
        include_once DRUPAL_ROOT . '/' . $include_file;
        $result[$hook]['includes'][] = $include_file;
386
      }
387

388 389 390 391 392 393 394 395
      // If these keys are left unspecified within overridden entries returned
      // by hook_theme(), carry them forward from the prior entry. This is so
      // that themes don't need to specify this information, since the module
      // that registered the theme hook already has.
      foreach (array('variables', 'render element', 'pattern', 'base hook') as $key) {
        if (!array_key_exists($key, $info) && isset($cache[$hook][$key])) {
          $result[$hook][$key] = $cache[$hook][$key];
        }
396
      }
397 398 399 400 401 402

      // The following apply only to theming hooks implemented as templates.
      if (isset($info['template'])) {
        // Prepend the current theming path when none is set.
        if (!isset($info['path'])) {
          $result[$hook]['template'] = $path . '/' . $info['template'];
403
        }
404
      }
405

406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427
      // Allow variable processors for all theming hooks, whether the hook is
      // implemented as a template or as a function.
      foreach ($variable_process_phases as $phase_key => $phase) {
        // Check for existing variable processors. Ensure arrayness.
        if (!isset($info[$phase_key]) || !is_array($info[$phase_key])) {
          $info[$phase_key] = array();
          $prefixes = array();
          if ($type == 'module') {
            // Default variable processor prefix.
            $prefixes[] = 'template';
            // Add all modules so they can intervene with their own variable
            // processors. This allows them to provide variable processors even
            // if they are not the owner of the current hook.
            $prefixes += module_list();
          }
          elseif ($type == 'theme_engine' || $type == 'base_theme_engine') {
            // Theme engines get an extra set that come before the normally
            // named variable processors.
            $prefixes[] = $name . '_engine';
            // The theme engine registers on behalf of the theme using the
            // theme's name.
            $prefixes[] = $theme;
428
          }
429 430 431 432
          else {
            // This applies when the theme manually registers their own variable
            // processors.
            $prefixes[] = $name;
433
          }
434 435
          foreach ($prefixes as $prefix) {
            // Only use non-hook-specific variable processors for theming hooks
436
            // implemented as templates. See theme().
437 438 439 440 441 442
            if (isset($info['template']) && function_exists($prefix . '_' . $phase)) {
              $info[$phase_key][] = $prefix . '_' . $phase;
            }
            if (function_exists($prefix . '_' . $phase . '_' . $hook)) {
              $info[$phase_key][] = $prefix . '_' . $phase . '_' . $hook;
            }
443
          }
444
        }
445 446 447 448 449 450 451 452 453 454 455
        // Check for the override flag and prevent the cached variable
        // processors from being used. This allows themes or theme engines to
        // remove variable processors set earlier in the registry build.
        if (!empty($info['override ' . $phase_key])) {
          // Flag not needed inside the registry.
          unset($result[$hook]['override ' . $phase_key]);
        }
        elseif (isset($cache[$hook][$phase_key]) && is_array($cache[$hook][$phase_key])) {
          $info[$phase_key] = array_merge($cache[$hook][$phase_key], $info[$phase_key]);
        }
        $result[$hook][$phase_key] = $info[$phase_key];
456
      }
457 458
    }

459
    // Merge the newly created theme hooks into the existing cache.
460 461
    $cache = array_merge($cache, $result);
  }
462

463
  // Let themes have variable processors even if they didn't register a template.
464 465
  if ($type == 'theme' || $type == 'base_theme') {
    foreach ($cache as $hook => $info) {
466 467 468
      // Check only if not registered by the theme or engine.
      if (empty($result[$hook])) {
        foreach ($variable_process_phases as $phase_key => $phase) {
469 470 471
          if (!isset($info[$phase_key])) {
            $cache[$hook][$phase_key] = array();
          }
472
          // Only use non-hook-specific variable processors for theming hooks
473
          // implemented as templates. See theme().
474 475
          if (isset($info['template']) && function_exists($name . '_' . $phase)) {
            $cache[$hook][$phase_key][] = $name . '_' . $phase;
476
          }
477 478
          if (function_exists($name . '_' . $phase . '_' . $hook)) {
            $cache[$hook][$phase_key][] = $name . '_' . $phase . '_' . $hook;
479
            $cache[$hook]['theme path'] = $path;
480 481 482
          }
          // Ensure uniqueness.
          $cache[$hook][$phase_key] = array_unique($cache[$hook][$phase_key]);
483 484 485 486
        }
      }
    }
  }
487 488 489
}

/**
490
 * Rebuild the theme registry cache.
491 492
 *
 * @param $theme
493
 *   The loaded $theme object as returned by list_themes().
494 495 496 497 498
 * @param $base_theme
 *   An array of loaded $theme objects representing the ancestor themes in
 *   oldest first order.
 * @param theme_engine
 *   The name of the theme engine.
499
 */
500
function _theme_build_registry($theme, $base_theme, $theme_engine) {
501
  $cache = array();
502 503
  // First, process the theme hooks advertised by modules. This will
  // serve as the basic registry.
504
  foreach (module_implements('theme') as $module) {
505 506 507 508 509
    _theme_process_registry($cache, $module, 'module', $module, drupal_get_path('module', $module));
  }

  // Process each base theme.
  foreach ($base_theme as $base) {
510
    // If the base theme uses a theme engine, process its hooks.
511 512 513 514 515
    $base_path = dirname($base->filename);
    if ($theme_engine) {
      _theme_process_registry($cache, $theme_engine, 'base_theme_engine', $base->name, $base_path);
    }
    _theme_process_registry($cache, $base->name, 'base_theme', $base->name, $base_path);
516 517
  }

518
  // And then the same thing, but for the theme.
519
  if ($theme_engine) {
520
    _theme_process_registry($cache, $theme_engine, 'theme_engine', $theme->name, dirname($theme->filename));
521 522
  }

523 524
  // Finally, hooks provided by the theme itself.
  _theme_process_registry($cache, $theme->name, 'theme', $theme->name, dirname($theme->filename));
525

526
  // Let modules alter the registry.
527
  drupal_alter('theme_registry', $cache);
528 529 530 531 532 533 534 535 536

  // Optimize the registry to not have empty arrays for functions.
  foreach ($cache as $hook => $info) {
    foreach (array('preprocess functions', 'process functions') as $phase) {
      if (empty($info[$phase])) {
        unset($cache[$hook][$phase]);
      }
    }
  }
537 538 539
  return $cache;
}

Dries's avatar
 
Dries committed
540
/**
541
 * Return a list of all currently available themes.
Dries's avatar
 
Dries committed
542
 *
543 544
 * Retrieved from the database, if available and the site is not in maintenance
 * mode; otherwise compiled freshly from the filesystem.
545
 *
Dries's avatar
 
Dries committed
546
 * @param $refresh
547
 *   Whether to reload the list of themes from the database. Defaults to FALSE.
548
 *
549
 * @return
550 551 552 553 554 555 556 557 558 559 560 561 562 563 564
 *   An associative array of the currently available themes. The keys are the
 *   names of the themes and the values are objects having the following
 *   properties:
 *   - 'filename': The name of the .info file.
 *   - 'name': The name of the theme.
 *   - 'status': 1 for enabled, 0 for disabled themes.
 *   - 'info': The contents of the .info file.
 *   - 'stylesheets': A two dimensional array, using the first key for the
 *     'media' attribute (e.g. 'all'), the second for the name of the file
 *     (e.g. style.css). The value is a complete filepath
 *     (e.g. themes/garland/style.css).
 *   - 'scripts': An associative array of JavaScripts, using the filename as key
 *     and the complete filepath as value.
 *   - 'engine': The name of the theme engine.
 *   - 'base theme': The name of the base theme.
Dries's avatar
 
Dries committed
565
 */
566
function list_themes($refresh = FALSE) {
567
  $list = &drupal_static(__FUNCTION__, array());
Dries's avatar
 
Dries committed
568 569

  if ($refresh) {
570
    $list = array();
571
    system_list_reset();
Dries's avatar
 
Dries committed
572 573
  }

574
  if (empty($list)) {
Dries's avatar
 
Dries committed
575
    $list = array();
576 577
    $themes = array();
    // Extract from the database only when it is available.
578
    // Also check that the site is not in the middle of an install or update.
579 580 581 582 583 584 585
    if (!defined('MAINTENANCE_MODE')) {
      try {
        foreach (system_list('theme') as $theme) {
          if (file_exists($theme->filename)) {
            $theme->info = unserialize($theme->info);
            $themes[] = $theme;
          }
586
        }
587
      }
588 589 590 591
      catch (Exception $e) {
        // If the database is not available, rebuild the theme data.
        $themes = _system_rebuild_theme_data();
      }
592 593
    }
    else {
594
      // Scan the installation when the database should not be read.
595
      $themes = _system_rebuild_theme_data();
596 597 598 599 600
    }

    foreach ($themes as $theme) {
      foreach ($theme->info['stylesheets'] as $media => $stylesheets) {
        foreach ($stylesheets as $stylesheet => $path) {
601
          $theme->stylesheets[$media][$stylesheet] = $path;
602
        }
603 604 605 606
      }
      foreach ($theme->info['scripts'] as $script => $path) {
        if (file_exists($path)) {
          $theme->scripts[$script] = $path;
607
        }
Dries's avatar
 
Dries committed
608
      }
609 610
      if (isset($theme->info['engine'])) {
        $theme->engine = $theme->info['engine'];
Dries's avatar
 
Dries committed
611
      }
612 613 614
      if (isset($theme->info['base theme'])) {
        $theme->base_theme = $theme->info['base theme'];
      }
615 616 617 618 619
      // Status is normally retrieved from the database. Add zero values when
      // read from the installation directory to prevent notices.
      if (!isset($theme->status)) {
        $theme->status = 0;
      }
620
      $list[$theme->name] = $theme;
Dries's avatar
 
Dries committed
621 622 623 624 625 626
    }
  }

  return $list;
}

Dries's avatar
 
Dries committed
627
/**
628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686
 * Generates themed output.
 *
 * All requests for themed output must go through this function. It examines
 * the request and routes it to the appropriate theme function or template, by
 * checking the theme registry.
 *
 * The first argument to this function is the name of the theme hook. For
 * instance, to theme a table, the theme hook name is 'table'. By default, this
 * theme hook could be implemented by a function called 'theme_table' or a
 * template file called 'table.tpl.php', but hook_theme() can override the
 * default function or template name.
 *
 * If the implementation is a template file, several functions are called
 * before the template file is invoked, to modify the $variables array. These
 * fall into the "preprocessing" phase and the "processing" phase, and are
 * executed (if they exist), in the following order (note that in the following
 * list, HOOK indicates the theme hook name, MODULE indicates a module name,
 * THEME indicates a theme name, and ENGINE indicates a theme engine name):
 * - template_preprocess(&$variables, $hook): Creates a default set of variables
 *   for all theme hooks.
 * - template_preprocess_HOOK(&$variables): Should be implemented by
 *   the module that registers the theme hook, to set up default variables.
 * - MODULE_preprocess(&$variables, $hook): hook_preprocess() is invoked on all
 *   implementing modules.
 * - MODULE_preprocess_HOOK(&$variables): hook_preprocess_HOOK() is invoked on
 *   all implementing modules, so that modules that didn't define the theme hook
 *   can alter the variables.
 * - ENGINE_engine_preprocess(&$variables, $hook): Allows the theme engine to
 *   set necessary variables for all theme hooks.
 * - ENGINE_engine_preprocess_HOOK(&$variables): Allows the theme engine to set
 *   necessary variables for the particular theme hook.
 * - THEME_preprocess(&$variables, $hook): Allows the theme to set necessary
 *   variables for all theme hooks.
 * - THEME_preprocess_HOOK(&$variables): Allows the theme to set necessary
 *   variables specific to the particular theme hook.
 * - template_process(&$variables, $hook): Creates a default set of variables
 *   for all theme hooks.
 * - template_process_HOOK(&$variables): This is the first processor specific
 *   to the theme hook; it should be implemented by the module that registers
 *   it.
 * - MODULE_process(&$variables, $hook): hook_process() is invoked on all
 *   implementing modules.
 * - MODULE_process_HOOK(&$variables): hook_process_HOOK() is invoked on
 *   on all implementing modules, so that modules that didn't define the theme
 *   hook can alter the variables.
 * - ENGINE_engine_process(&$variables, $hook): Allows the theme engine to set
 *   necessary variables for all theme hooks.
 * - ENGINE_engine_process_HOOK(&$variables): Allows the theme engine to set
 *   necessary variables for the particular theme hook.
 * - ENGINE_process(&$variables, $hook): Allows the theme engine to process the
 *   variables.
 * - ENGINE_process_HOOK(&$variables): Allows the theme engine to process the
 *   variables specific to the theme hook.
 * - THEME_process(&$variables, $hook):  Allows the theme to process the
 *   variables.
 * - THEME_process_HOOK(&$variables):  Allows the theme to process the
 *   variables specific to the theme hook.
 *
 * If the implementation is a function, only the theme-hook-specific preprocess
687
 * and process functions (the ones ending in _HOOK) are called from the
688 689 690
 * list above. This is because theme hooks with function implementations
 * need to be fast, and calling the non-theme-hook-specific preprocess and
 * process functions for them would incur a noticeable performance penalty.
691
 *
692
 * There are two special variables that these preprocess and process functions
693 694 695 696 697 698 699 700 701 702
 * can set: 'theme_hook_suggestion' and 'theme_hook_suggestions'. These will be
 * merged together to form a list of 'suggested' alternate theme hooks to use,
 * in reverse order of priority. theme_hook_suggestion will always be a higher
 * priority than items in theme_hook_suggestions. theme() will use the
 * highest priority implementation that exists. If none exists, theme() will
 * use the implementation for the theme hook it was called with. These
 * suggestions are similar to and are used for similar reasons as calling
 * theme() with an array as the $hook parameter (see below). The difference
 * is whether the suggestions are determined by the code that calls theme() or
 * by a preprocess or process function.
703
 *
704
 * @param $hook
705 706 707 708
 *   The name of the theme hook to call. If the name contains a
 *   double-underscore ('__') and there isn't an implementation for the full
 *   name, the part before the '__' is checked. This allows a fallback to a more
 *   generic implementation. For example, if theme('links__node', ...) is
709
 *   called, but there is no implementation of that theme hook, then the 'links'
710 711 712 713 714 715 716 717
 *   implementation is used. This process is iterative, so if
 *   theme('links__contextual__node', ...) is called, theme() checks for the
 *   following implementations, and uses the first one that exists:
 *   - links__contextual__node
 *   - links__contextual
 *   - links
 *   This allows themes to create specific theme implementations for named
 *   objects and contexts of otherwise generic theme hooks. The $hook parameter
718
 *   may also be an array, in which case the first theme hook that has an
719 720
 *   implementation is used. This allows for the code that calls theme() to
 *   explicitly specify the fallback order in a situation where using the '__'
721
 *   convention is not desired or is insufficient.
722 723 724 725
 * @param $variables
 *   An associative array of variables to merge with defaults from the theme
 *   registry, pass to preprocess and process functions for modification, and
 *   finally, pass to the function or template implementing the theme hook.
726 727 728
 *   Alternatively, this can be a renderable array, in which case, its
 *   properties are mapped to variables expected by the theme hook
 *   implementations.
729
 *
730
 * @return
731
 *   An HTML string representing the themed output.
Dries's avatar
 
Dries committed
732
 */
733
function theme($hook, $variables = array()) {
734
  static $hooks = NULL;
735 736 737 738 739 740 741 742

  // If called before all modules are loaded, we do not necessarily have a full
  // theme registry to work with, and therefore cannot process the theme
  // request properly. See also _theme_load_registry().
  if (!module_load_all(NULL) && !defined('MAINTENANCE_MODE')) {
    throw new Exception(t('theme() may not be called until all modules are loaded.'));
  }

743
  if (!isset($hooks)) {
744
    drupal_theme_initialize();
745
    $hooks = theme_get_registry();
746
  }
747

748 749
  // If an array of hook candidates were passed, use the first one that has an
  // implementation.
750 751 752 753 754 755 756 757 758
  if (is_array($hook)) {
    foreach ($hook as $candidate) {
      if (isset($hooks[$candidate])) {
        break;
      }
    }
    $hook = $candidate;
  }

759 760
  // If there's no implementation, check for more generic fallbacks. If there's
  // still no implementation, log an error and return an empty string.
761
  if (!isset($hooks[$hook])) {
762 763 764 765 766 767 768 769 770 771 772 773
    // Iteratively strip everything after the last '__' delimiter, until an
    // implementation is found.
    while ($pos = strrpos($hook, '__')) {
      $hook = substr($hook, 0, $pos);
      if (isset($hooks[$hook])) {
        break;
      }
    }
    if (!isset($hooks[$hook])) {
      watchdog('theme', 'Theme key "@key" not found.', array('@key' => $hook), WATCHDOG_WARNING);
      return '';
    }
774 775
  }

776
  $info = $hooks[$hook];
777 778 779
  global $theme_path;
  $temp = $theme_path;
  // point path_to_theme() to the currently used theme path:
780
  $theme_path = $info['theme path'];
Dries's avatar
 
Dries committed
781

782
  // Include a file if the theme function or variable processor is held elsewhere.
783 784 785
  if (!empty($info['includes'])) {
    foreach ($info['includes'] as $include_file) {
      include_once DRUPAL_ROOT . '/' . $include_file;
786 787
    }
  }
788 789

  // If a renderable array is passed as $variables, then set $variables to
790
  // the arguments expected by the theme function.
791 792 793
  if (isset($variables['#theme']) || isset($variables['#theme_wrappers'])) {
    $element = $variables;
    $variables = array();
794 795
    if (isset($info['variables'])) {
      foreach (array_keys($info['variables']) as $name) {
796 797 798
        if (isset($element["#$name"])) {
          $variables[$name] = $element["#$name"];
        }
799 800
      }
    }
801 802 803
    else {
      $variables[$info['render element']] = $element;
    }
804
  }
805

806
  // Merge in argument defaults.
807 808 809 810 811
  if (!empty($info['variables'])) {
    $variables += $info['variables'];
  }
  elseif (!empty($info['render element'])) {
    $variables += array($info['render element'] => array());
812
  }
813

814
  // Invoke the variable processors, if any. The processors may specify
815 816 817 818 819 820 821 822 823 824 825 826 827
  // alternate suggestions for which hook's template/function to use. If the
  // hook is a suggestion of a base hook, invoke the variable processors of
  // the base hook, but retain the suggestion as a high priority suggestion to
  // be used unless overridden by a variable processor function.
  if (isset($info['base hook'])) {
    $base_hook = $info['base hook'];
    $base_hook_info = $hooks[$base_hook];
    if (isset($base_hook_info['preprocess functions']) || isset($base_hook_info['process functions'])) {
      $variables['theme_hook_suggestion'] = $hook;
      $hook = $base_hook;
      $info = $base_hook_info;
    }
  }
828
  if (isset($info['preprocess functions']) || isset($info['process functions'])) {
829
    $variables['theme_hook_suggestions'] = array();
830 831 832 833 834 835 836
    foreach (array('preprocess functions', 'process functions') as $phase) {
      if (!empty($info[$phase])) {
        foreach ($info[$phase] as $processor_function) {
          if (function_exists($processor_function)) {
            // We don't want a poorly behaved process function changing $hook.
            $hook_clone = $hook;
            $processor_function($variables, $hook_clone);
837 838 839
          }
        }
      }
840
    }
841 842 843 844 845 846 847 848 849 850 851 852
    // If the preprocess/process functions specified hook suggestions, and the
    // suggestion exists in the theme registry, use it instead of the hook that
    // theme() was called with. This allows the preprocess/process step to
    // route to a more specific theme hook. For example, a function may call
    // theme('node', ...), but a preprocess function can add 'node__article' as
    // a suggestion, enabling a theme to have an alternate template file for
    // article nodes. Suggestions are checked in the following order:
    // - The 'theme_hook_suggestion' variable is checked first. It overrides
    //   all others.
    // - The 'theme_hook_suggestions' variable is checked in FILO order, so the
    //   last suggestion added to the array takes precedence over suggestions
    //   added earlier.
853
    $suggestions = array();
854 855
    if (!empty($variables['theme_hook_suggestions'])) {
      $suggestions = $variables['theme_hook_suggestions'];
856
    }
857 858
    if (!empty($variables['theme_hook_suggestion'])) {
      $suggestions[] = $variables['theme_hook_suggestion'];
859 860
    }
    foreach (array_reverse($suggestions) as $suggestion) {
861 862
      if (isset($hooks[$suggestion])) {
        $info = $hooks[$suggestion];
863
        break;
864
      }
865
    }
866
  }
867

868 869
  // Generate the output using either a function or a template.
  if (isset($info['function'])) {
870
    if (function_exists($info['function'])) {
871
      $output = $info['function']($variables);
Dries's avatar
 
Dries committed
872
    }
Dries's avatar
 
Dries committed
873
  }
874
  else {
875
    // Default render function and extension.
876 877 878
    $render_function = 'theme_render_template';
    $extension = '.tpl.php';

879
    // The theme engine may use a different extension and a different renderer.
880 881
    global $theme_engine;
    if (isset($theme_engine)) {
882
      if ($info['type'] != 'module') {
883 884
        if (function_exists($theme_engine . '_render_template')) {
          $render_function = $theme_engine . '_render_template';
885
        }
886
        $extension_function = $theme_engine . '_extension';
887 888 889 890 891 892
        if (function_exists($extension_function)) {
          $extension = $extension_function();
        }
      }
    }

893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908
    // In some cases, a template implementation may not have had
    // template_preprocess() run (for example, if the default implementation is
    // a function, but a template overrides that default implementation). In
    // these cases, a template should still be able to expect to have access to
    // the variables provided by template_preprocess(), so we add them here if
    // they don't already exist. We don't want to run template_preprocess()
    // twice (it would be inefficient and mess up zebra striping), so we use the
    // 'directory' variable to determine if it has already run, which while not
    // completely intuitive, is reasonably safe, and allows us to save on the
    // overhead of adding some new variable to track that.
    if (!isset($variables['directory'])) {
      $default_template_variables = array();
      template_preprocess($default_template_variables, $hook);
      $variables += $default_template_variables;
    }

909 910 911 912
    // Render the output using the template file.
    $template_file = $info['template'] . $extension;
    if (isset($info['path'])) {
      $template_file = $info['path'] . '/' . $template_file;
913
    }
914
    $output = $render_function($template_file, $variables);
Dries's avatar
 
Dries committed
915
  }
916

917 918 919
  // restore path_to_theme()
  $theme_path = $temp;
  return $output;
920 921
}

Dries's avatar
 
Dries committed
922
/**
923 924 925 926 927 928 929 930
 * Return the path to the current themed element.
 *
 * It can point to the active theme or the module handling a themed implementation.
 * For example, when invoked within the scope of a theming call it will depend
 * on where the theming function is handled. If implemented from a module, it
 * will point to the module. If implemented from the active theme, it will point
 * to the active theme. When called outside the scope of a theming call, it will
 * always point to the active theme.
Dries's avatar
 
Dries committed
931
 */
Dries's avatar
 
Dries committed
932
function path_to_theme() {
933
  global $theme_path;
Dries's avatar
 
Dries committed
934

935
  if (!isset($theme_path)) {
936
    drupal_theme_initialize();
937 938
  }

939
  return $theme_path;
940 941
}

942
/**
943
 * Allow themes and/or theme engines to easily discover overridden theme functions.
944 945 946 947 948 949
 *
 * @param $cache
 *   The existing cache of theme hooks to test against.
 * @param $prefixes
 *   An array of prefixes to test, in reverse order of importance.
 *
950
 * @return $implementations
951 952 953
 *   The functions found, suitable for returning from hook_theme;
 */
function drupal_find_theme_functions($cache, $prefixes) {
954
  $implementations = array();
955 956 957 958
  $functions = get_defined_functions();

  foreach ($cache as $hook => $info) {
    foreach ($prefixes as $prefix) {
959 960 961 962 963 964 965 966 967 968 969
      // Find theme functions that implement possible "suggestion" variants of
      // registered theme hooks and add those as new registered theme hooks.
      // The 'pattern' key defines a common prefix that all suggestions must
      // start with. The default is the name of the hook followed by '__'. An
      // 'base hook' key is added to each entry made for a found suggestion,
      // so that common functionality can be implemented for all suggestions of
      // the same base hook. To keep things simple, deep heirarchy of
      // suggestions is not supported: each suggestion's 'base hook' key
      // refers to a base hook, not to another suggestion, and all suggestions
      // are found using the base hook's pattern, not a pattern from an
      // intermediary suggestion.
970
      $pattern = isset($info['pattern']) ? $info['pattern'] : ($hook . '__');
971
      if (!isset($info['base hook']) && !empty($pattern)) {
972
        $matches = preg_grep('/^' . $prefix . '_' . $pattern . '/', $functions['user']);
973 974
        if ($matches) {
          foreach ($matches as $match) {
975
            $new_hook = str_replace($prefix . '_', '', $match);
976
            $arg_name = isset($info['variables']) ? 'variables' : 'render element';
977
            $implementations[$new_hook] = array(
978
              'function' => $match,
979
              $arg_name => $info[$arg_name],
980
              'base hook' => $hook,
981 982 983 984
            );
          }
        }
      }
985 986 987
      // Find theme functions that implement registered theme hooks and include
      // that in what is returned so that the registry knows that the theme has
      // this implementation.
988
      if (function_exists($prefix . '_' . $hook)) {
989
        $implementations[$hook] = array(
990
          'function' => $prefix . '_' . $hook,
991 992 993 994 995
        );
      }
    }
  }

996
  return $implementations;
997 998 999
}

/**
1000
 * Allow themes and/or theme engines to easily discover overridden templates.
1001 1002 1003 1004 1005 1006 1007 1008 1009
 *
 * @param $cache
 *   The existing cache of theme hooks to test against.
 * @param $extension
 *   The extension that these templates will have.
 * @param $path
 *   The path to search.
 */
function drupal_find_theme_templates($cache, $extension, $path) {
1010
  $implementations = array();
1011

1012 1013 1014 1015
  // Collect paths to all sub-themes grouped by base themes. These will be
  // used for filtering. This allows base themes to have sub-themes in its
  // folder hierarchy without affecting the base themes template discovery.
  $theme_paths = array();
1016
  foreach (list_themes() as $theme_info) {
1017 1018 1019 1020 1021 1022 1023 1024 1025
    if (!empty($theme_info->base_theme)) {
      $theme_paths[$theme_info->base_theme][$theme_info->name] = dirname($theme_info->filename);
    }
  }
  foreach ($theme_paths as $basetheme => $subthemes) {
    foreach ($subthemes as $subtheme => $subtheme_path) {
      if (isset($theme_paths[$subtheme])) {
        $theme_paths[$basetheme] = array_merge($theme_paths[$basetheme], $theme_paths[$subtheme]);
      }
1026 1027
    }
  }
1028 1029
  global $theme;
  $subtheme_paths = isset($theme_paths[$theme]) ? $theme_paths[$theme] : array();
1030

1031
  // Escape the periods in the extension.
1032
  $regex = '/' . str_replace('.', '\.', $extension) . '$/';
1033
  // Get a listing of all template files in the path to search.
1034
  $files = drupal_system_listing($regex, $path, 'name', 0);
1035 1036 1037 1038

  // Find templates that implement registered theme hooks and include that in
  // what is returned so that the registry knows that the theme has this
  // implementation.
1039
  foreach ($files as $template => $file) {