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CssCollectionRenderer.php 8.05 KiB
<?php
/**
* Contains \Drupal\Core\Asset\CssCollectionRenderer.
*/
namespace Drupal\Core\Asset;
use Drupal\Component\Utility\String;
use Drupal\Core\State\StateInterface;
/**
* Renders CSS assets.
*/
class CssCollectionRenderer implements AssetCollectionRendererInterface {
/**
* The state key/value store.
*
* @var \Drupal\Core\State\StateInterface
*/
protected $state;
/**
* Constructs a CssCollectionRenderer.
*
* @param \Drupal\Core\State\StateInterface
* The state key/value store.
*/
public function __construct(StateInterface $state) {
$this->state = $state;
}
/**
* {@inheritdoc}
*/
public function render(array $css_assets) {
$elements = array();
// A dummy query-string is added to filenames, to gain control over
// browser-caching. The string changes on every update or full cache
// flush, forcing browsers to load a new copy of the files, as the
// URL changed.
$query_string = $this->state->get('system.css_js_query_string') ?: '0';
// Defaults for LINK and STYLE elements.
$link_element_defaults = array(
'#type' => 'html_tag',
'#tag' => 'link',
'#attributes' => array(
'rel' => 'stylesheet',
),
);
$style_element_defaults = array(
'#type' => 'html_tag',
'#tag' => 'style',
);
// For filthy IE hack.
$current_ie_group_keys = NULL;
$get_ie_group_key = function ($css_asset) {
return array($css_asset['type'], $css_asset['preprocess'], $css_asset['group'], $css_asset['every_page'], $css_asset['media'], $css_asset['browsers']);
};
// Loop through all CSS assets, by key, to allow for the special IE
// workaround.
$css_assets_keys = array_keys($css_assets);
for ($i = 0; $i < count($css_assets_keys); $i++) {
$css_asset = $css_assets[$css_assets_keys[$i]];
switch ($css_asset['type']) { // For file items, there are three possibilites.
// - There are up to 31 CSS assets on the page (some of which may be
// aggregated). In this case, output a LINK tag for file CSS assets.
// - There are more than 31 CSS assets on the page, yet we must stay
// below IE<10's limit of 31 total CSS inclussion tags, we handle this
// in two ways:
// - file CSS assets that are not eligible for aggregation (their
// 'preprocess' flag has been set to FALSE): in this case, output a
// LINK tag.
// - file CSS assets that can be aggregated (and possibly have been):
// in this case, figure out which subsequent file CSS assets share
// the same key properties ('group', 'every_page', 'media' and
// 'browsers') and output this group into as few STYLE tags as
// possible (a STYLE tag may contain only 31 @import statements).
case 'file':
// The dummy query string needs to be added to the URL to control
// browser-caching.
$query_string_separator = (strpos($css_asset['data'], '?') !== FALSE) ? '&' : '?';
// As long as the current page will not run into IE's limit for CSS
// assets: output a LINK tag for a file CSS asset.
if (count($css_assets) <= 31) {
$element = $link_element_defaults;
$element['#attributes']['href'] = file_create_url($css_asset['data']) . $query_string_separator . $query_string;
$element['#attributes']['media'] = $css_asset['media'];
$element['#browsers'] = $css_asset['browsers'];
$elements[] = $element;
}
// The current page will run into IE's limits for CSS assets: work
// around these limits by performing a light form of grouping.
// Once Drupal only needs to support IE10 and later, we can drop this.
else {
// The file CSS asset is ineligible for aggregation: output it in a
// LINK tag.
if (!$css_asset['preprocess']) {
$element = $link_element_defaults;
$element['#attributes']['href'] = file_create_url($css_asset['data']) . $query_string_separator . $query_string;
$element['#attributes']['media'] = $css_asset['media'];
$element['#browsers'] = $css_asset['browsers'];
$elements[] = $element;
}
// The file CSS asset can be aggregated, but hasn't been: combine
// multiple items into as few STYLE tags as possible.
else {
$import = array();
// Start with the current CSS asset, iterate over subsequent CSS
// assets and find which ones have the same 'type', 'group',
// 'every_page', 'preprocess', 'media' and 'browsers' properties.
$j = $i;
$next_css_asset = $css_asset;
$current_ie_group_key = $get_ie_group_key($css_asset);
do {
// The dummy query string needs to be added to the URL to
// control browser-caching. IE7 does not support a media type on
// the @import statement, so we instead specify the media for
// the group on the STYLE tag.
$import[] = '@import url("' . String::checkPlain(file_create_url($next_css_asset['data']) . '?' . $query_string) . '");';
// Move the outer for loop skip the next item, since we
// processed it here.
$i = $j;
// Retrieve next CSS asset, unless there is none: then break.
if ($j + 1 < count($css_assets_keys)) {
$j++;
$next_css_asset = $css_assets[$css_assets_keys[$j]];
}
else {
break;
}
} while ($get_ie_group_key($next_css_asset) == $current_ie_group_key);
// In addition to IE's limit of 31 total CSS inclusion tags, it
// also has a limit of 31 @import statements per STYLE tag.
while (!empty($import)) {
$import_batch = array_slice($import, 0, 31);
$import = array_slice($import, 31);
$element = $style_element_defaults;
// This simplifies the JavaScript regex, allowing each line
// (separated by \n) to be treated as a completely different
// string. This means that we can use ^ and $ on one line at a
// time, and not worry about style tags since they'll never
// match the regex.
$element['#value'] = "\n" . implode("\n", $import_batch) . "\n";
$element['#attributes']['media'] = $css_asset['media'];
$element['#browsers'] = $css_asset['browsers'];
$elements[] = $element;
}
}
}
break;
// Output a STYLE tag for an inline CSS asset. The asset's 'data'
// property contains the CSS content.
case 'inline':
$element = $style_element_defaults;
$element['#value'] = $css_asset['data'];
$element['#attributes']['media'] = $css_asset['media'];
$element['#browsers'] = $css_asset['browsers'];
// For inline CSS to validate as XHTML, all CSS containing XHTML needs
// to be wrapped in CDATA. To make that backwards compatible with HTML
// 4, we need to comment out the CDATA-tag.
$element['#value_prefix'] = "\n/* <![CDATA[ */\n";
$element['#value_suffix'] = "\n/* ]]> */\n";
$elements[] = $element;
break;
// Output a LINK tag for an external CSS asset. The asset's 'data'
// property contains the full URL.
case 'external':
$element = $link_element_defaults;
$element['#attributes']['href'] = $css_asset['data'];
$element['#attributes']['media'] = $css_asset['media'];
$element['#browsers'] = $css_asset['browsers'];
$elements[] = $element;
break;
default:
throw new \Exception('Invalid CSS asset type.');
}
}
return $elements;
}
}