vendor/symfony/twig-bridge/Symfony/Bridge/Twig/Form/TwigRendererEngine.php

   1 <?php
   2
   3 /*
   4  * This file is part of the Symfony package.
   5  *
   6  * (c) Fabien Potencier <fabien@symfony.com>
   7  *
   8  * For the full copyright and license information, please view the LICENSE
   9  * file that was distributed with this source code.
  10  */
  11
  12 namespace Symfony\Bridge\Twig\Form;
  13
  14 use Symfony\Component\Form\AbstractRendererEngine;
  15 use Symfony\Component\Form\FormView;
  16
  17 /**
  18  * @author Bernhard Schussek <bschussek@gmail.com>
  19  */
  20 class TwigRendererEngine extends AbstractRendererEngine implements TwigRendererEngineInterface
  21 {
  22     /**
  23      * @var \Twig_Environment
  24      */
  25     private $environment;
  26
  27     /**
  28      * @var \Twig_Template
  29      */
  30     private $template;
  31
  32     /**
  33      * {@inheritdoc}
  34      */
  35     public function setEnvironment(\Twig_Environment $environment)
  36     {
  37         $this->environment = $environment;
  38     }
  39
  40     /**
  41      * {@inheritdoc}
  42      */
  43     public function renderBlock(FormView $view, $resource, $blockName, array $variables = array())
  44     {
  45         $cacheKey = $view->vars[self::CACHE_KEY_VAR];
  46
  47         $context = $this->environment->mergeGlobals($variables);
  48
  49         ob_start();
  50
  51         // By contract,This method can only be called after getting the resource
  52         // (which is passed to the method). Getting a resource for the first time
  53         // (with an empty cache) is guaranteed to invoke loadResourcesFromTheme(),
  54         // where the property $template is initialized.
  55
  56         // We do not call renderBlock here to avoid too many nested level calls
  57         // (XDebug limits the level to 100 by default)
  58         $this->template->displayBlock($blockName, $context, $this->resources[$cacheKey]);
  59
  60         return ob_get_clean();
  61     }
  62
  63     /**
  64      * Loads the cache with the resource for a given block name.
  65      *
  66      * This implementation eagerly loads all blocks of the themes assigned to the given view
  67      * and all of its ancestors views. This is necessary, because Twig receives the
  68      * list of blocks later. At that point, all blocks must already be loaded, for the
  69      * case that the function "block()" is used in the Twig template.
  70      *
  71      * @see getResourceForBlock()
  72      *
  73      * @param string   $cacheKey  The cache key of the form view.
  74      * @param FormView $view      The form view for finding the applying themes.
  75      * @param string   $blockName The name of the block to load.
  76      *
  77      * @return Boolean True if the resource could be loaded, false otherwise.
  78      */
  79     protected function loadResourceForBlockName($cacheKey, FormView $view, $blockName)
  80     {
  81         // The caller guarantees that $this->resources[$cacheKey][$block] is
  82         // not set, but it doesn't have to check whether $this->resources[$cacheKey]
  83         // is set. If $this->resources[$cacheKey] is set, all themes for this
  84         // $cacheKey are already loaded (due to the eager population, see doc comment).
  85         if (isset($this->resources[$cacheKey])) {
  86             // As said in the previous, the caller guarantees that
  87             // $this->resources[$cacheKey][$block] is not set. Since the themes are
  88             // already loaded, it can only be a non-existing block.
  89             $this->resources[$cacheKey][$blockName] = false;
  90
  91             return false;
  92         }
  93
  94         // Recursively try to find the block in the themes assigned to $view,
  95         // then of its parent view, then of the parent view of the parent and so on.
  96         // When the root view is reached in this recursion, also the default
  97         // themes are taken into account.
  98
  99         // Check each theme whether it contains the searched block
 100         if (isset($this->themes[$cacheKey])) {
 101             for ($i = count($this->themes[$cacheKey]) - 1; $i >= 0; --$i) {
 102                 $this->loadResourcesFromTheme($cacheKey, $this->themes[$cacheKey][$i]);
 103                 // CONTINUE LOADING (see doc comment)
 104             }
 105         }
 106
 107         // Check the default themes once we reach the root view without success
 108         if (!$view->parent) {
 109             for ($i = count($this->defaultThemes) - 1; $i >= 0; --$i) {
 110                 $this->loadResourcesFromTheme($cacheKey, $this->defaultThemes[$i]);
 111                 // CONTINUE LOADING (see doc comment)
 112             }
 113         }
 114
 115         // Proceed with the themes of the parent view
 116         if ($view->parent) {
 117             $parentCacheKey = $view->parent->vars[self::CACHE_KEY_VAR];
 118
 119             if (!isset($this->resources[$parentCacheKey])) {
 120                 $this->loadResourceForBlockName($parentCacheKey, $view->parent, $blockName);
 121             }
 122
 123             // EAGER CACHE POPULATION (see doc comment)
 124             foreach ($this->resources[$parentCacheKey] as $nestedBlockName => $resource) {
 125                 if (!isset($this->resources[$cacheKey][$nestedBlockName])) {
 126                     $this->resources[$cacheKey][$nestedBlockName] = $resource;
 127                 }
 128             }
 129         }
 130
 131         // Even though we loaded the themes, it can happen that none of them
 132         // contains the searched block
 133         if (!isset($this->resources[$cacheKey][$blockName])) {
 134             // Cache that we didn't find anything to speed up further accesses
 135             $this->resources[$cacheKey][$blockName] = false;
 136         }
 137
 138         return false !== $this->resources[$cacheKey][$blockName];
 139     }
 140
 141     /**
 142      * Loads the resources for all blocks in a theme.
 143      *
 144      * @param string $cacheKey The cache key for storing the resource.
 145      * @param mixed  $theme    The theme to load the block from. This parameter
 146      *                         is passed by reference, because it might be necessary
 147      *                         to initialize the theme first. Any changes made to
 148      *                         this variable will be kept and be available upon
 149      *                         further calls to this method using the same theme.
 150      */
 151     protected function loadResourcesFromTheme($cacheKey, &$theme)
 152     {
 153         if (!$theme instanceof \Twig_Template) {
 154             /* @var \Twig_Template $theme */
 155             $theme = $this->environment->loadTemplate($theme);
 156         }
 157
 158         if (null === $this->template) {
 159             // Store the first \Twig_Template instance that we find so that
 160             // we can call displayBlock() later on. It doesn't matter *which*
 161             // template we use for that, since we pass the used blocks manually
 162             // anyway.
 163             $this->template = $theme;
 164         }
 165
 166         // Use a separate variable for the inheritance traversal, because
 167         // theme is a reference and we don't want to change it.
 168         $currentTheme = $theme;
 169
 170         // The do loop takes care of template inheritance.
 171         // Add blocks from all templates in the inheritance tree, but avoid
 172         // overriding blocks already set.
 173         do {
 174             foreach ($currentTheme->getBlocks() as $block => $blockData) {
 175                 if (!isset($this->resources[$cacheKey][$block])) {
 176                     // The resource given back is the key to the bucket that
 177                     // contains this block.
 178                     $this->resources[$cacheKey][$block] = $blockData;
 179                 }
 180             }
 181         } while (false !== $currentTheme = $currentTheme->getParent(array()));
 182     }
 183 }