/**
* {@inheritdoc}
*
* The cache file name is retrieved on a page load via a lookup variable that
* contains an associative array. The array key is the hash of the file names
* in $css while the value is the cache file name. The cache file is generated
* in two cases. First, if there is no file name value for the key, which will
* happen if a new file name has been added to $css or after the lookup
* variable is emptied to force a rebuild of the cache. Second, the cache file
* is generated if it is missing on disk. Old cache files are not deleted
* immediately when the lookup variable is emptied, but are deleted after a
* configurable period (@code system.performance.stale_file_threshold @endcode)
* to ensure that files referenced by a cached page will still be available.
*/
public function optimize(array $css_assets)
{
// Group the assets.
$css_groups = $this->grouper->group($css_assets);
// Now optimize (concatenate + minify) and dump each asset group, unless
// that was already done, in which case it should appear in
// drupal_css_cache_files.
// Drupal contrib can override this default CSS aggregator to keep the same
// grouping, optimizing and dumping, but change the strategy that is used to
// determine when the aggregate should be rebuilt (e.g. mtime, HTTPS …).
$map = $this->state->get('drupal_css_cache_files') ?: array();
$css_assets = array();
foreach ($css_groups as $order => $css_group) {
// We have to return a single asset, not a group of assets. It is now up
// to one of the pieces of code in the switch statement below to set the
// 'data' property to the appropriate value.
$css_assets[$order] = $css_group;
unset($css_assets[$order]['items']);
switch ($css_group['type']) {
case 'file':
// No preprocessing, single CSS asset: just use the existing URI.
if (!$css_group['preprocess']) {
$uri = $css_group['items'][0]['data'];
$css_assets[$order]['data'] = $uri;
} else {
$key = $this->generateHash($css_group);
$uri = '';
if (isset($map[$key])) {
$uri = $map[$key];
}
if (empty($uri) || !file_exists($uri)) {
// Optimize each asset within the group.
$data = '';
foreach ($css_group['items'] as $css_asset) {
$data .= $this->optimizer->optimize($css_asset);
}
// Per the W3C specification at
// http://www.w3.org/TR/REC-CSS2/cascade.html#at-import, @import
// rules must proceed any other style, so we move those to the
// top.
$regexp = '/@import[^;]+;/i';
preg_match_all($regexp, $data, $matches);
$data = preg_replace($regexp, '', $data);
$data = implode('', $matches[0]) . $data;
// Dump the optimized CSS for this group into an aggregate file.
$uri = $this->dumper->dump($data, 'css');
// Set the URI for this group's aggregate file.
$css_assets[$order]['data'] = $uri;
// Persist the URI for this aggregate file.
$map[$key] = $uri;
$this->state->set('drupal_css_cache_files', $map);
} else {
// Use the persisted URI for the optimized CSS file.
$css_assets[$order]['data'] = $uri;
}
$css_assets[$order]['preprocessed'] = TRUE;
}
break;
case 'inline':
// We don't do any caching for inline CSS assets.
$data = '';
foreach ($css_group['items'] as $css_asset) {
$data .= $this->optimizer->optimize($css_asset);
}
unset($css_assets[$order]['data']['items']);
$css_assets[$order]['data'] = $data;
break;
case 'external':
// We don't do any aggregation and hence also no caching for external
// CSS assets.
$uri = $css_group['items'][0]['data'];
$css_assets[$order]['data'] = $uri;
break;
}
}
return $css_assets;
}
/**
* {@inheritdoc}
*
* The cache file name is retrieved on a page load via a lookup variable that
* contains an associative array. The array key is the hash of the names in
* $files while the value is the cache file name. The cache file is generated
* in two cases. First, if there is no file name value for the key, which will
* happen if a new file name has been added to $files or after the lookup
* variable is emptied to force a rebuild of the cache. Second, the cache file
* is generated if it is missing on disk. Old cache files are not deleted
* immediately when the lookup variable is emptied, but are deleted after a
* configurable period (@code system.performance.stale_file_threshold @endcode)
* to ensure that files referenced by a cached page will still be available.
*/
public function optimize(array $js_assets)
{
// Group the assets.
$js_groups = $this->grouper->group($js_assets);
// Now optimize (concatenate, not minify) and dump each asset group, unless
// that was already done, in which case it should appear in
// system.js_cache_files.
// Drupal contrib can override this default JS aggregator to keep the same
// grouping, optimizing and dumping, but change the strategy that is used to
// determine when the aggregate should be rebuilt (e.g. mtime, HTTPS …).
$map = $this->state->get('system.js_cache_files') ?: array();
$js_assets = array();
foreach ($js_groups as $order => $js_group) {
// We have to return a single asset, not a group of assets. It is now up
// to one of the pieces of code in the switch statement below to set the
// 'data' property to the appropriate value.
$js_assets[$order] = $js_group;
unset($js_assets[$order]['items']);
switch ($js_group['type']) {
case 'file':
// No preprocessing, single JS asset: just use the existing URI.
if (!$js_group['preprocess']) {
$uri = $js_group['items'][0]['data'];
$js_assets[$order]['data'] = $uri;
} else {
$key = $this->generateHash($js_group);
$uri = '';
if (isset($map[$key])) {
$uri = $map[$key];
}
if (empty($uri) || !file_exists($uri)) {
// Concatenate each asset within the group.
$data = '';
foreach ($js_group['items'] as $js_asset) {
// Optimize this JS file, but only if it's not yet minified.
if (isset($js_asset['minified']) && $js_asset['minified']) {
$data .= file_get_contents($js_asset['data']);
} else {
$data .= $this->optimizer->optimize($js_asset);
}
// Append a ';' and a newline after each JS file to prevent them
// from running together.
$data .= ";\n";
}
// Remove unwanted JS code that cause issues.
$data = $this->optimizer->clean($data);
// Dump the optimized JS for this group into an aggregate file.
$uri = $this->dumper->dump($data, 'js');
// Set the URI for this group's aggregate file.
$js_assets[$order]['data'] = $uri;
// Persist the URI for this aggregate file.
$map[$key] = $uri;
$this->state->set('system.js_cache_files', $map);
} else {
// Use the persisted URI for the optimized JS file.
$js_assets[$order]['data'] = $uri;
}
$js_assets[$order]['preprocessed'] = TRUE;
}
break;
case 'external':
case 'setting':
case 'inline':
// We don't do any aggregation and hence also no caching for external,
// setting or inline JS assets.
$uri = $js_group['items'][0]['data'];
$js_assets[$order]['data'] = $uri;
break;
}
}
return $js_assets;
}