theme.inc 121 KB
Newer Older
Dries's avatar
   
Dries committed
1
<?php
2

3
/**
Dries's avatar
   
Dries committed
4
 * @file
5
 * The theme system, which controls the output of Drupal.
Dries's avatar
   
Dries committed
6
7
8
9
 *
 * The theme system allows for nearly all output of the Drupal system to be
 * customized by user themes.
 */
Dries's avatar
   
Dries committed
10

11
use Drupal\Core\Cache\CacheBackendInterface;
12
use Drupal\Core\Config\Config;
13
use Drupal\Core\Language\Language;
14
use Drupal\Core\Template\Attribute;
15
use Drupal\Core\Utility\ThemeRegistry;
16
use Drupal\Core\Theme\ThemeSettings;
17

18
/**
19
 * @defgroup content_flags Content markers
20
21
22
23
 * @{
 * Markers used by theme_mark() and node_mark() to designate content.
 * @see theme_mark(), node_mark()
 */
24
25
26
27

/**
 * Mark content as read.
 */
28
const MARK_READ = 0;
29
30
31
32

/**
 * Mark content as being new.
 */
33
const MARK_NEW = 1;
34
35
36
37

/**
 * Mark content as being updated.
 */
38
const MARK_UPDATED = 2;
39

40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
/**
 * A responsive table class; hide table cell on narrow devices.
 *
 * Indicates that a column has medium priority and thus can be hidden on narrow
 * width devices and shown on medium+ width devices (i.e. tablets and desktops).
 */
const RESPONSIVE_PRIORITY_MEDIUM = 'priority-medium';

/**
 * A responsive table class; only show table cell on wide devices.
 *
 * Indicates that a column has low priority and thus can be hidden on narrow
 * and medium viewports and shown on wide devices (i.e. desktops).
 */
const RESPONSIVE_PRIORITY_LOW = 'priority-low';

56
/**
57
 * @} End of "defgroup content_flags".
58
59
 */

60
61
62
63
/**
 * Determines if a theme is available to use.
 *
 * @param $theme
64
65
 *   Either the name of a theme or a full theme object.
 *
66
67
68
69
70
 * @return
 *   Boolean TRUE if the theme is enabled or is the site administration theme;
 *   FALSE otherwise.
 */
function drupal_theme_access($theme) {
71
  if (is_object($theme)) {
72
    return !empty($theme->status);
73
74
75
  }
  else {
    $themes = list_themes();
76
    return !empty($themes[$theme]->status);
77
78
79
  }
}

Dries's avatar
   
Dries committed
80
/**
81
 * Initializes the theme system by loading the theme.
Dries's avatar
   
Dries committed
82
 */
83
function drupal_theme_initialize() {
84
  global $theme, $user, $theme_key;
85
86
87
88
89

  // If $theme is already set, assume the others are set, too, and do nothing
  if (isset($theme)) {
    return;
  }
Dries's avatar
   
Dries committed
90

91
  drupal_bootstrap(DRUPAL_BOOTSTRAP_DATABASE);
Dries's avatar
   
Dries committed
92
93
  $themes = list_themes();

94
  // Only select the user selected theme if it is available in the
95
  // list of themes that can be accessed.
96
  $theme = !empty($user->theme) && drupal_theme_access($user->theme) ? $user->theme : config('system.theme')->get('default');
Dries's avatar
   
Dries committed
97

98
99
  // 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.
100
  $custom_theme = menu_get_custom_theme();
101
  $theme = !empty($custom_theme) ? $custom_theme : $theme;
Dries's avatar
   
Dries committed
102
103
104
105

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

106
107
108
109
  // Find all our ancestor themes and put them in an array.
  $base_theme = array();
  $ancestor = $theme;
  while ($ancestor && isset($themes[$ancestor]->base_theme)) {
110
    $ancestor = $themes[$ancestor]->base_theme;
111
    $base_theme[] = $themes[$ancestor];
112
  }
113
  _drupal_theme_initialize($themes[$theme], array_reverse($base_theme));
114
115
116

  // Themes can have alter functions, so reset the drupal_alter() cache.
  drupal_static_reset('drupal_alter');
117
118
119
}

/**
120
121
122
 * Initializes the theme system given already loaded information.
 *
 * This function is useful to initialize a theme when no database is present.
123
124
125
126
 *
 * @param $theme
 *   An object with the following information:
 *     filename
127
 *       The .info.yml file for this theme. The 'path' to
128
129
130
131
132
133
134
135
136
137
138
139
140
141
 *       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.
142
143
 * @param $registry_callback
 *   The callback to invoke to set the theme registry.
144
 */
145
function _drupal_theme_initialize($theme, $base_theme = array(), $registry_callback = '_theme_load_registry') {
146
147
148
149
150
151
  global $theme_info, $base_theme_info, $theme_engine, $theme_path;
  $theme_info = $theme;
  $base_theme_info = $base_theme;

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

152
153
154
155
  // 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();
156
157
158
159
  // CSS file basenames to override, pointing to the final, overridden filepath.
  $theme->stylesheets_override = array();
  // CSS file basenames to remove.
  $theme->stylesheets_remove = array();
160
161
162
163
164
165
166
167
168
169

  // 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;
        }
      }
    }
170
171
172
173
174
175
176
177
178
179
180
181
    $base_theme_path = dirname($base->filename);
    if (!empty($base->info['stylesheets-remove'])) {
      foreach ($base->info['stylesheets-remove'] as $basename) {
        $theme->stylesheets_remove[$basename] = $base_theme_path . '/' . $basename;
      }
    }
    if (!empty($base->info['stylesheets-override'])) {
      foreach ($base->info['stylesheets-override'] as $name) {
        $basename = drupal_basename($name);
        $theme->stylesheets_override[$basename] = $base_theme_path . '/' . $name;
      }
    }
182
183
  }

184
185
186
  // Add stylesheets used by this theme.
  if (!empty($theme->stylesheets)) {
    foreach ($theme->stylesheets as $media => $stylesheets) {
187
188
189
190
191
      foreach ($stylesheets as $name => $stylesheet) {
        $final_stylesheets[$media][$name] = $stylesheet;
      }
    }
  }
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
  if (!empty($theme->info['stylesheets-remove'])) {
    foreach ($theme->info['stylesheets-remove'] as $basename) {
      $theme->stylesheets_remove[$basename] = $theme_path . '/' . $basename;

      if (isset($theme->stylesheets_override[$basename])) {
        unset($theme->stylesheets_override[$basename]);
      }
    }
  }
  if (!empty($theme->info['stylesheets-override'])) {
    foreach ($theme->info['stylesheets-override'] as $name) {
      $basename = drupal_basename($name);
      $theme->stylesheets_override[$basename] = $theme_path . '/' . $name;

      if (isset($theme->stylesheets_remove[$basename])) {
        unset($theme->stylesheets_remove[$basename]);
      }
    }
  }
211
212
213
214

  // And now add the stylesheets properly
  foreach ($final_stylesheets as $media => $stylesheets) {
    foreach ($stylesheets as $stylesheet) {
215
      drupal_add_css($stylesheet, array('group' => CSS_AGGREGATE_THEME, 'every_page' => TRUE, 'media' => $media));
216
217
218
219
220
221
222
223
224
225
226
    }
  }

  // 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;
227
      }
Dries's avatar
   
Dries committed
228
229
    }
  }
230

231
232
  // Add scripts used by this theme.
  if (!empty($theme->scripts)) {
233
234
    foreach ($theme->scripts as $name => $script) {
      $final_scripts[$name] = $script;
235
236
237
    }
  }

238
239
  // Add scripts used by this theme.
  foreach ($final_scripts as $script) {
240
    drupal_add_js($script, array('group' => JS_THEME, 'every_page' => TRUE));
241
242
  }

243
244
245
246
247
  $theme_engine = NULL;

  // Initialize the theme.
  if (isset($theme->engine)) {
    // Include the engine.
248
    include_once DRUPAL_ROOT . '/' . $theme->owner;
249
250

    $theme_engine = $theme->engine;
251
    if (function_exists($theme_engine . '_init')) {
252
      foreach ($base_theme as $base) {
253
        call_user_func($theme_engine . '_init', $base);
254
      }
255
      call_user_func($theme_engine . '_init', $theme);
256
257
258
259
260
261
262
    }
  }
  else {
    // include non-engine theme files
    foreach ($base_theme as $base) {
      // Include the theme file or the engine.
      if (!empty($base->owner)) {
263
        include_once DRUPAL_ROOT . '/' . $base->owner;
264
265
266
267
      }
    }
    // and our theme gets one too.
    if (!empty($theme->owner)) {
268
      include_once DRUPAL_ROOT . '/' . $theme->owner;
Dries's avatar
   
Dries committed
269
270
    }
  }
271
272

  // Always include Twig as the default theme engine.
273
  include_once DRUPAL_ROOT . '/core/themes/engines/twig/twig.engine';
274

275
276
  if (isset($registry_callback)) {
    _theme_registry_callback($registry_callback, array($theme, $base_theme, $theme_engine));
277
  }
Dries's avatar
   
Dries committed
278
279
}

280
/**
281
 * Gets the theme registry.
282
 *
283
 * @param bool $complete
284
 *   Optional boolean to indicate whether to return the complete theme registry
285
286
287
288
289
290
291
 *   array or an instance of the Drupal\Core\Utility\ThemeRegistry class.
 *   If TRUE, the complete theme registry array will be returned. This is useful
 *   if you want to foreach over the whole registry, use array_* functions or
 *   inspect it in a debugger. If FALSE, an instance of the
 *   Drupal\Core\Utility\ThemeRegistry class will be returned, this provides an
 *   ArrayObject which allows it to be accessed with array syntax and isset(),
 *   and should be more lightweight than the full registry. Defaults to TRUE.
292
 *
293
 * @return
294
295
 *   The complete theme registry array, or an instance of the
 *   Drupal\Core\Utility\ThemeRegistry class.
296
 */
297
function theme_get_registry($complete = TRUE) {
298
299
300
301
302
303
304
305
306
307
308
309
310
311
  // Use the advanced drupal_static() pattern, since this is called very often.
  static $drupal_static_fast;
  if (!isset($drupal_static_fast)) {
    $drupal_static_fast['registry'] = &drupal_static('theme_get_registry');
  }
  $theme_registry = &$drupal_static_fast['registry'];

  // Initialize the theme, if this is called early in the bootstrap, or after
  // static variables have been reset.
  if (!is_array($theme_registry)) {
    drupal_theme_initialize();
    $theme_registry = array();
  }

312
  $key = (int) $complete;
313

314
  if (!isset($theme_registry[$key])) {
315
    list($callback, $arguments) = _theme_registry_callback();
316
317
318
319
    if (!$complete) {
      $arguments[] = FALSE;
    }
    $theme_registry[$key] = call_user_func_array($callback, $arguments);
320
321
  }

322
  return $theme_registry[$key];
323
324
325
}

/**
326
 * Sets the callback that will be used by theme_get_registry().
327
 *
328
329
330
331
 * @param $callback
 *   The name of the callback function.
 * @param $arguments
 *   The arguments to pass to the function.
332
 */
333
334
335
336
function _theme_registry_callback($callback = NULL, array $arguments = array()) {
  static $stored;
  if (isset($callback)) {
    $stored = array($callback, $arguments);
337
  }
338
  return $stored;
339
340
341
}

/**
342
 * Gets the theme_registry cache; if it doesn't exist, builds it.
343
344
 *
 * @param $theme
345
 *   The loaded $theme object as returned by list_themes().
346
347
348
 * @param $base_theme
 *   An array of loaded $theme objects representing the ancestor themes in
 *   oldest first order.
349
 * @param $theme_engine
350
 *   The name of the theme engine.
351
352
 * @param $complete
 *   Whether to load the complete theme registry or an instance of the
353
 *   Drupal\Core\Utility\ThemeRegistry class.
354
355
 *
 * @return
356
357
 *   The theme registry array, or an instance of the
 *   Drupal\Core\Utility\ThemeRegistry class.
358
 */
359
360
361
362
363
364
365
366
367
368
369
370
function _theme_load_registry($theme, $base_theme = NULL, $theme_engine = NULL, $complete = TRUE) {
  if ($complete) {
    // Check the theme registry cache; if it exists, use it.
    $cached = cache()->get("theme_registry:$theme->name");
    if (isset($cached->data)) {
      $registry = $cached->data;
    }
    else {
      // If not, build one and cache it.
      $registry = _theme_build_registry($theme, $base_theme, $theme_engine);
      // Only persist this registry if all modules are loaded. This assures a
      // complete set of theme hooks.
371
      if (Drupal::moduleHandler()->isLoaded()) {
372
373
374
375
        _theme_save_registry($theme, $registry);
      }
    }
    return $registry;
376
377
  }
  else {
378
    return new ThemeRegistry('theme_registry:runtime:' . $theme->name, 'cache', array('theme_registry' => TRUE), Drupal::moduleHandler()->isLoaded());
379
380
381
382
  }
}

/**
383
 * Writes the theme_registry cache into the database.
384
385
 */
function _theme_save_registry($theme, $registry) {
386
  cache()->set("theme_registry:$theme->name", $registry, CacheBackendInterface::CACHE_PERMANENT, array('theme_registry' => TRUE));
387
388
389
}

/**
390
391
392
393
 * Forces the system to rebuild the theme registry.
 *
 * This function should be called when modules are added to the system, or when
 * a dynamic system needs to add more theme hooks.
394
 */
395
function drupal_theme_rebuild() {
396
  drupal_static_reset('theme_get_registry');
397
  cache()->invalidateTags(array('theme_registry' => TRUE));
398
399
400
}

/**
401
 * Process a single implementation of hook_theme().
402
 *
403
404
405
406
 * @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:
407
408
 *   - 'type': The passed-in $type.
 *   - 'theme path': The passed-in $path.
409
 *   - 'function': The name of the function generating output for this theme
410
411
412
413
414
 *     hook. Either defined explicitly in hook_theme() or, if neither
 *     'function' nor 'template' is defined, then the default theme function
 *     name is used. The default theme function name is the theme hook prefixed
 *     by either 'theme_' for modules or '$name_' for everything else. If
 *     'function' is defined, 'template' is not used.
415
416
 *   - 'template': The filename of the template generating output for this
 *     theme hook. The template is in the directory defined by the 'path' key of
417
 *     hook_theme() or defaults to "$path/templates".
418
 *   - 'variables': The variables for this theme hook as defined in
419
420
 *     hook_theme(). If there is more than one implementation and 'variables'
 *     is not specified in a later one, then the previous definition is kept.
421
422
423
424
 *   - '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.
425
 *   - 'preprocess functions': See theme() for detailed documentation.
426
 *   - 'process functions': See theme() for detailed documentation.
427
428
429
430
431
432
433
434
435
436
437
438
439
440
 * @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 $name is. For example, modules/system or
441
 *   themes/bartik.
442
 *
443
444
445
 * @see theme()
 * @see hook_theme()
 * @see list_themes()
446
 */
447
function _theme_process_registry(&$cache, $name, $type, $theme, $path) {
448
  $result = array();
449

450
  // Processor functions work in two distinct phases with the process
451
  // functions always being executed after the preprocess functions.
452
  $variable_process_phases = array(
453
454
455
456
    'preprocess functions' => 'preprocess',
    'process functions'    => 'process',
  );

457
458
459
460
461
462
463
  $hook_defaults = array(
    'variables' => TRUE,
    'render element' => TRUE,
    'pattern' => TRUE,
    'base hook' => TRUE,
  );

464
465
  $module_list = array_keys(Drupal::moduleHandler()->getModuleList());

466
467
468
  // Invoke the hook_theme() implementation, process what is returned, and
  // merge it into $cache.
  $function = $name . '_theme';
469
  if (function_exists($function)) {
470
    $result = $function($cache, $type, $theme, $path);
471
    foreach ($result as $hook => $info) {
472
473
474
475
476
477
478
      // When a theme or engine overrides a module's theme function
      // $result[$hook] will only contain key/value pairs for information being
      // overridden.  Pull the rest of the information from what was defined by
      // an earlier hook.

      // Fill in the type and path of the module, theme, or engine that
      // implements this theme function.
479
      $result[$hook]['type'] = $type;
480
      $result[$hook]['theme path'] = $path;
481
482

      // If function and file are omitted, default to standard naming
483
      // conventions.
484
      if (!isset($info['template']) && !isset($info['function'])) {
485
        $result[$hook]['function'] = ($type == 'module' ? 'theme_' : $name . '_') . $hook;
486
      }
487

488
489
      if (isset($cache[$hook]['includes'])) {
        $result[$hook]['includes'] = $cache[$hook]['includes'];
490
      }
491
492
493
494
495

      // If the theme implementation defines a file, then also use the path
      // that it defined. Otherwise use the default path. This allows
      // system.module to declare theme functions on behalf of core .include
      // files.
496
497
498
499
500
      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;
501
      }
502

503
504
505
506
      // If the default keys are not set, use the default values registered
      // by the module.
      if (isset($cache[$hook])) {
        $result[$hook] += array_intersect_key($cache[$hook], $hook_defaults);
507
      }
508
509
510
511
512

      // 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'])) {
513
          $result[$hook]['template'] = $path . '/templates/' . $info['template'];
514
        }
515
      }
516

517
518
519
520
521
522
523
524
525
526
527
528
529
      // 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.
530
            $prefixes = array_merge($prefixes, $module_list);
531
532
533
534
535
536
537
538
          }
          elseif ($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;
539
          }
540
541
542
543
          else {
            // This applies when the theme manually registers their own variable
            // processors.
            $prefixes[] = $name;
544
          }
545
546
          foreach ($prefixes as $prefix) {
            // Only use non-hook-specific variable processors for theming hooks
547
            // implemented as templates. See theme().
548
549
550
551
552
553
            if (isset($info['template']) && function_exists($prefix . '_' . $phase)) {
              $info[$phase_key][] = $prefix . '_' . $phase;
            }
            if (function_exists($prefix . '_' . $phase . '_' . $hook)) {
              $info[$phase_key][] = $prefix . '_' . $phase . '_' . $hook;
            }
554
          }
555
        }
556
557
558
559
560
561
562
563
564
565
566
        // Check for the override flag and prevent the cached variable
        // processors from being used. This allows themes or theme engines to
        // remove variable processors set earlier in the registry build.
        if (!empty($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];
567
      }
568
569
    }

570
    // Merge the newly created theme hooks into the existing cache.
571
    $cache = $result + $cache;
572
  }
573

574
575
  // Let themes have variable processors even if they didn't register a
  // template.
576
577
  if ($type == 'theme' || $type == 'base_theme') {
    foreach ($cache as $hook => $info) {
578
579
580
      // Check only if not registered by the theme or engine.
      if (empty($result[$hook])) {
        foreach ($variable_process_phases as $phase_key => $phase) {
581
582
583
          if (!isset($info[$phase_key])) {
            $cache[$hook][$phase_key] = array();
          }
584
          // Only use non-hook-specific variable processors for theming hooks
585
          // implemented as templates. See theme().
586
587
          if (isset($info['template']) && function_exists($name . '_' . $phase)) {
            $cache[$hook][$phase_key][] = $name . '_' . $phase;
588
          }
589
590
          if (function_exists($name . '_' . $phase . '_' . $hook)) {
            $cache[$hook][$phase_key][] = $name . '_' . $phase . '_' . $hook;
591
            $cache[$hook]['theme path'] = $path;
592
593
594
          }
          // Ensure uniqueness.
          $cache[$hook][$phase_key] = array_unique($cache[$hook][$phase_key]);
595
596
597
598
        }
      }
    }
  }
599
600
601
}

/**
602
 * Builds the theme registry cache.
603
604
 *
 * @param $theme
605
 *   The loaded $theme object as returned by list_themes().
606
607
608
 * @param $base_theme
 *   An array of loaded $theme objects representing the ancestor themes in
 *   oldest first order.
609
 * @param $theme_engine
610
 *   The name of the theme engine.
611
 */
612
function _theme_build_registry($theme, $base_theme, $theme_engine) {
613
  $cache = array();
614
  // First, process the theme hooks advertised by modules. This will
615
616
617
  // serve as the basic registry. Since the list of enabled modules is the same
  // regardless of the theme used, this is cached in its own entry to save
  // building it for every theme.
618
  if ($cached = cache()->get('theme_registry:build:modules')) {
619
620
621
622
623
624
625
    $cache = $cached->data;
  }
  else {
    foreach (module_implements('theme') as $module) {
      _theme_process_registry($cache, $module, 'module', $module, drupal_get_path('module', $module));
    }
    // Only cache this registry if all modules are loaded.
626
    if (Drupal::moduleHandler()->isLoaded()) {
627
      cache()->set("theme_registry:build:modules", $cache, CacheBackendInterface::CACHE_PERMANENT, array('theme_registry' => TRUE));
628
    }
629
630
631
632
  }

  // Process each base theme.
  foreach ($base_theme as $base) {
633
    // If the base theme uses a theme engine, process its hooks.
634
635
636
637
638
    $base_path = dirname($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);
639
640
  }

641
  // And then the same thing, but for the theme.
642
  if ($theme_engine) {
643
    _theme_process_registry($cache, $theme_engine, 'theme_engine', $theme->name, dirname($theme->filename));
644
645
  }

646
647
  // Finally, hooks provided by the theme itself.
  _theme_process_registry($cache, $theme->name, 'theme', $theme->name, dirname($theme->filename));
648

649
  // Let modules alter the registry.
650
  drupal_alter('theme_registry', $cache);
651
652
653
654
655
656
657
658
659

  // 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]);
      }
    }
  }
660
661
662
  return $cache;
}

Dries's avatar
   
Dries committed
663
/**
664
 * Returns a list of all currently available themes.
Dries's avatar
   
Dries committed
665
 *
666
667
 * Retrieved from the database, if available and the site is not in maintenance
 * mode; otherwise compiled freshly from the filesystem.
668
 *
Dries's avatar
   
Dries committed
669
 * @param $refresh
670
 *   Whether to reload the list of themes from the database. Defaults to FALSE.
671
 *
672
 * @return
673
 *   An associative array of the currently available themes. The keys are the
674
 *   themes' machine names and the values are objects having the following
675
 *   properties:
676
 *   - filename: The filepath and name of the .info.yml file.
677
678
 *   - name: The machine name of the theme.
 *   - status: 1 for enabled, 0 for disabled themes.
679
 *   - info: The contents of the .info.yml file.
680
681
682
683
 *   - 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/bartik/style.css). Not set if no stylesheets are defined in the
684
 *     .info.yml file.
685
686
 *   - scripts: An associative array of JavaScripts, using the filename as key
 *     and the complete filepath as value. Not set if no scripts are defined in
687
 *     the .info.yml file.
688
689
690
 *   - prefix: The base theme engine prefix.
 *   - engine: The machine name of the theme engine.
 *   - base_theme: If this is a sub-theme, the machine name of the base theme
691
 *     defined in the .info.yml file. Otherwise, the element is not set.
692
693
694
695
696
697
698
699
700
701
702
703
704
705
 *   - base_themes: If this is a sub-theme, an associative array of the
 *     base-theme ancestors of this theme, starting with this theme's base
 *     theme, then the base theme's own base theme, etc. Each entry has an
 *     array key equal to the theme's machine name, and a value equal to the
 *     human-readable theme name; if a theme with matching machine name does
 *     not exist in the system, the value will instead be NULL (and since the
 *     system would not know whether that theme itself has a base theme, that
 *     will end the array of base themes). This is not set if the theme is not
 *     a sub-theme.
 *   - sub_themes: An associative array of themes on the system that are
 *     either direct sub-themes (that is, they declare this theme to be
 *     their base theme), direct sub-themes of sub-themes, etc. The keys are
 *     the themes' machine names, and the values are the themes' human-readable
 *     names. This element is not set if there are no themes on the system that
706
 *     declare this theme as their base theme.
707
 */
708
function list_themes($refresh = FALSE) {
709
  $list = &drupal_static(__FUNCTION__, array());
Dries's avatar
   
Dries committed
710
711

  if ($refresh) {
712
    $list = array();
713
    system_list_reset();
Dries's avatar
   
Dries committed
714
715
  }

716
  if (empty($list)) {
Dries's avatar
   
Dries committed
717
    $list = array();
718
    // Extract from the database only when it is available.
719
    // Also check that the site is not in the middle of an install or update.
720
721
    if (!defined('MAINTENANCE_MODE')) {
      try {
722
        $themes = system_list('theme');
723
      }
724
725
726
727
      catch (Exception $e) {
        // If the database is not available, rebuild the theme data.
        $themes = _system_rebuild_theme_data();
      }
728
729
    }
    else {
730
      // Scan the installation when the database should not be read.
731
      $themes = _system_rebuild_theme_data();
732
733
734
735
736
    }

    foreach ($themes as $theme) {
      foreach ($theme->info['stylesheets'] as $media => $stylesheets) {
        foreach ($stylesheets as $stylesheet => $path) {
737
          $theme->stylesheets[$media][$stylesheet] = $path;
738
        }
739
740
      }
      foreach ($theme->info['scripts'] as $script => $path) {
741
        $theme->scripts[$script] = $path;
Dries's avatar
   
Dries committed
742
      }
743
744
      if (isset($theme->info['engine'])) {
        $theme->engine = $theme->info['engine'];
Dries's avatar
   
Dries committed
745
      }
746
747
748
      if (isset($theme->info['base theme'])) {
        $theme->base_theme = $theme->info['base theme'];
      }
749
750
751
752
753
      // Status is normally retrieved from the database. Add zero values when
      // read from the installation directory to prevent notices.
      if (!isset($theme->status)) {
        $theme->status = 0;
      }
754
      $list[$theme->name] = $theme;
Dries's avatar
   
Dries committed
755
756
757
758
759
760
    }
  }

  return $list;
}

761
/**
762
 * Finds all the base themes for the specified theme.
763
 *
764
765
 * Themes can inherit templates and function implementations from earlier
 * themes.
766
767
768
769
770
771
 *
 * @param $themes
 *   An array of available themes.
 * @param $key
 *   The name of the theme whose base we are looking for.
 * @param $used_keys
772
773
774
 *   (optional) A recursion parameter preventing endless loops. Defaults to
 *   NULL.
 *
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
 * @return
 *   Returns an array of all of the theme's ancestors; the first element's value
 *   will be NULL if an error occurred.
 */
function drupal_find_base_themes($themes, $key, $used_keys = array()) {
  $base_key = $themes[$key]->info['base theme'];
  // Does the base theme exist?
  if (!isset($themes[$base_key])) {
    return array($base_key => NULL);
  }

  $current_base_theme = array($base_key => $themes[$base_key]->info['name']);

  // Is the base theme itself a child of another theme?
  if (isset($themes[$base_key]->info['base theme'])) {
    // Do we already know the base themes of this theme?
    if (isset($themes[$base_key]->base_themes)) {
      return $themes[$base_key]->base_themes + $current_base_theme;
    }
    // Prevent loops.
    if (!empty($used_keys[$base_key])) {
      return array($base_key => NULL);
    }
    $used_keys[$base_key] = TRUE;
    return drupal_find_base_themes($themes, $base_key, $used_keys) + $current_base_theme;
  }
  // If we get here, then this is our parent theme.
  return $current_base_theme;
}

Dries's avatar
   
Dries committed
805
/**
806
807
808
 * Generates themed output.
 *
 * All requests for themed output must go through this function. It examines
809
810
811
 * the request and routes it to the appropriate
 * @link themeable theme function or template @endlink, by checking the theme
 * registry.
812
 *
813
 * @section sec_theme_hooks Theme Hooks
814
815
816
817
818
819
820
 * Most commonly, the first argument to this function is the name of the theme
 * hook. For instance, to theme a taxonomy term, the theme hook name is
 * 'taxonomy_term'. Modules register theme hooks within a hook_theme()
 * implementation and provide a default implementation via a function named
 * theme_HOOK() (e.g., theme_taxonomy_term()) or via a template file named
 * according to the value of the 'template' key registered with the theme hook
 * (see hook_theme() for details). Default templates are implemented with the
821
 * Twig rendering engine and are named the same as the theme hook, with
822
823
824
 * underscores changed to hyphens, so for the 'taxonomy_term' theme hook, the
 * default template is 'taxonomy-term.tpl.php'.
 *
825
 * @subsection sub_overriding_theme_hooks Overriding Theme Hooks
826
827
828
829
830
831
832
833
 * Themes may also register new theme hooks within a hook_theme()
 * implementation, but it is more common for themes to override default
 * implementations provided by modules than to register entirely new theme
 * hooks. Themes can override a default implementation by implementing a
 * function named THEME_HOOK() (for example, the 'bartik' theme overrides the
 * default implementation of the 'menu_tree' theme hook by implementing a
 * bartik_menu_tree() function), or by adding a template file within its folder
 * structure that follows the template naming structure used by the theme's
834
835
836
 * rendering engine (for example, since the Bartik theme uses the Twig rendering
 * engine, it overrides the default implementation of the 'page' theme hook by
 * containing a 'page.html.twig' file within its folder structure).
837
 *
838
 * @subsection sub_preprocess_templates Preprocessing for Template Files
839
840
841
842
843
844
 * If the implementation is a template file, several functions are called
 * before the template file is invoked, to modify the $variables array. These
 * fall into the "preprocessing" phase and the "processing" phase, and are
 * executed (if they exist), in the following order (note that in the following
 * list, HOOK indicates the theme hook name, MODULE indicates a module name,
 * THEME indicates a theme name, and ENGINE indicates a theme engine name):
845
846
 * - template_preprocess(&$variables, $hook): Creates a default set of
 *   variables for all theme hooks with template implementations.
847
848
 * - template_preprocess_HOOK(&$variables): Should be implemented by the module
 *   that registers the theme hook, to set up default variables.
849
850
851
 * - MODULE_preprocess(&$variables, $hook): hook_preprocess() is invoked on all
 *   implementing modules.
 * - MODULE_preprocess_HOOK(&$variables): hook_preprocess_HOOK() is invoked on
852
853
 *   all implementing modules, so that modules that didn't define the theme
 *   hook can alter the variables.
854
 * - ENGINE_engine_preprocess(&$variables, $hook): Allows the theme engine to
855
 *   set necessary variables for all theme hooks with template implementations.
856
857
858
 * - ENGINE_engine_preprocess_HOOK(&$variables): Allows the theme engine to set
 *   necessary variables for the particular theme hook.
 * - THEME_preprocess(&$variables, $hook): Allows the theme to set necessary
859
 *   variables for all theme hooks with template implementations.
860
861
 * - THEME_preprocess_HOOK(&$variables): Allows the theme to set necessary
 *   variables specific to the particular theme hook.
862
863
864
865
866
 * - template_process(&$variables, $hook): Creates an additional set of default
 *   variables for all theme hooks with template implementations. The variables
 *   created in this function are derived from ones created by
 *   template_preprocess(), but potentially altered by the other preprocess
 *   functions listed above. For example, any preprocess function can add to or
867
 *   modify the $variables['attributes'] variable, and after all of them
868
869
870
871
872
 *   have finished executing, template_process() flattens it into a
 *   $variables['attributes'] string for convenient use by templates.
 * - template_process_HOOK(&$variables): Should be implemented by the module
 *   that registers the theme hook, if it needs to perform additional variable
 *   processing after all preprocess functions have finished.
873
874
875
876
877
 * - 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.
878
879
880
881
 * - ENGINE_engine_process(&$variables, $hook): Allows the theme engine to
 *   process variables for all theme hooks with template implementations.
 * - ENGINE_engine_process_HOOK(&$variables): Allows the theme engine to process
 *   the variables specific to the theme hook.
882
 * - THEME_process(&$variables, $hook):  Allows the theme to process the
883
 *   variables for all theme hooks with template implementations.
884
885
886
 * - THEME_process_HOOK(&$variables):  Allows the theme to process the
 *   variables specific to the theme hook.
 *
887
 * @subsection sub_preprocess_theme_funcs Preprocessing for Theme Functions
888
 * If the implementation is a function, only the theme-hook-specific preprocess
889
 * and process functions (the ones ending in _HOOK) are called from the
890
891
892
 * 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.
893
 *
894
 * @subsection sub_alternate_suggestions Suggesting Alternate Hooks
895
 * There are two special variables that these preprocess and process functions
896
897
898
899
900
901
902
903
904
905
 * 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.
906
 *
907
 * @param $hook
908
909
 *   The name of the theme hook to call. If the name contains a
 *   double-underscore ('__') and there isn't an implementation for the full
910
911
912
913
 *   name, the part before the '__' is checked. This allows a fallback to a
 *   more generic implementation. For example, if theme('links__node', ...) is
 *   called, but there is no implementation of that theme hook, then the
 *   'links' implementation is used. This process is iterative, so if
914
915
916
917
918
919
920
 *   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
921
 *   may also be an array, in which case the first theme hook that has an
922
923
 *   implementation is used. This allows for the code that calls theme() to
 *   explicitly specify the fallback order in a situation where using the '__'
924
 *   convention is not desired or is insufficient.
925
926
927
928
 * @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.
929
930
931
 *   Alternatively, this can be a renderable array, in which case, its
 *   properties are mapped to variables expected by the theme hook
 *   implementations.
932
 *
933
 * @return
934
 *   An HTML string representing the themed output.
935
936
 *
 * @see themeable
937
938
939
 * @see hook_theme()
 * @see template_preprocess()
 * @see template_process()
Dries's avatar
   
Dries committed
940
 */
941
function theme($hook, $variables = array()) {
942
  static $default_attributes;
943
944
945
  // 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().
946
  if (!Drupal::moduleHandler()->isLoaded() && !defined('MAINTENANCE_MODE')) {
947
948
949
    throw new Exception(t('theme() may not be called until all modules are loaded.'));
  }

950
  $hooks = theme_get_registry(FALSE);
951

952
953
  // If an array of hook candidates were passed, use the first one that has an
  // implementation.
954
955
956
957
958
959
960
961
  if (is_array($hook)) {
    foreach ($hook as $candidate) {
      if (isset($hooks[$candidate])) {
        break;
      }
    }
    $hook = $candidate;
  }
962
963
964
  // Save the original theme hook, so it can be supplied to theme variable
  // preprocess callbacks.
  $original_hook = $hook;
965

966
967
  // If there's no implementation, check for more generic fallbacks. If there's
  // still no implementation, log an error and return an empty string.
968
  if (!isset($hooks[$hook])) {
969
970
971
972
973
974
975
976
977
    // 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[$hook])) {
978
979
980
      // Only log a message when not trying theme suggestions ($hook being an
      // array).
      if (!isset($candidate)) {
981
        watchdog('theme', 'Theme hook %hook not found.', array('%hook' => $hook), WATCHDOG_WARNING);
982
      }
983
984
      return '';
    }
985
986
  }

987
  $info = $hooks[$hook];
988
989
990
  global $theme_path;
  $temp = $theme_path;
  // point path_to_theme() to the currently used theme path:
991
  $theme_path = $info['theme path'];
Dries's avatar
   
Dries committed
992

993
994
  // Include a file if the theme function or variable processor is held
  // elsewhere.
995
996
997
  if (!empty($info['includes'])) {
    foreach ($info['includes'] as $include_file) {
      include_once DRUPAL_ROOT . '/' . $include_file;
998
999
    }
  }
1000
1001

  // If a renderable array is passed as $variables, then set $variables to
1002
  // the arguments expected by the theme function.
1003
1004
1005
  if (isset($variables['#theme']) || isset($variables['#theme_wrappers'])) {
    $element = $variables;
    $variables = array();
1006
1007
    if (isset($info['variables'])) {
      foreach (array_keys($info['variables']) as $name) {
1008
1009
1010
        if (isset($element["#$name"])) {
          $variables[$name] = $element["#$name"];
        }
1011
1012
      }
    }
1013
1014
    else {
      $variables[$info['render element']] = $element;
1015
1016
      // Give a hint to render engines to prevent infinite recursion.
      $variables[$info['render element']]['#render_children'] = TRUE;
1017
    }
1018
  }
1019

1020
  // Merge in argument defaults.
1021
1022
1023
1024
1025
  if (!empty($info['variables'])) {
    $variables += $info['variables'];
  }
  elseif (!empty($info['render element'])) {
    $variables += array($info['render element'] => array());
1026
  }