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<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
/**
* This file is responsible for serving the one huge CSS of each theme.
*
* @package core
* @copyright 2009 Petr Skoda (skodak) {@link http://skodak.org}
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
// Disable moodle specific debug messages and any errors in output,
// comment out when debugging or better look into error log!
define('NO_DEBUG_DISPLAY', true);
define('ABORT_AFTER_CONFIG', true);
require('../config.php');
require_once($CFG->dirroot.'/lib/csslib.php');
if ($slashargument = min_get_slash_argument()) {
$slashargument = ltrim($slashargument, '/');
if (substr_count($slashargument, '/') < 2) {
css_send_css_not_found();
}
if (strpos($slashargument, '_s/') === 0) {
// Can't use SVG.
$slashargument = substr($slashargument, 3);
$usesvg = false;
} else {
$usesvg = true;
}
list($themename, $rev, $type) = explode('/', $slashargument, 3);
$themename = min_clean_param($themename, 'SAFEDIR');
$rev = min_clean_param($rev, 'RAW');
$type = min_clean_param($type, 'SAFEDIR');
} else {
$themename = min_optional_param('theme', 'standard', 'SAFEDIR');
$rev = min_optional_param('rev', 0, 'RAW');
$type = min_optional_param('type', 'all', 'SAFEDIR');
$usesvg = (bool)min_optional_param('svg', '1', 'INT');
}
// Check if we received a theme sub revision which allows us
// to handle local caching on a per theme basis.
$values = explode('_', $rev);
$rev = min_clean_param(array_shift($values), 'INT');
$themesubrev = array_shift($values);
if (!is_null($themesubrev)) {
$themesubrev = min_clean_param($themesubrev, 'INT');
}
// Check that type fits into the expected values.
if (!in_array($type, ['all', 'all-rtl', 'editor'])) {
css_send_css_not_found();
}
if (file_exists("$CFG->dirroot/theme/$themename/config.php")) {
// The theme exists in standard location - ok.
} else if (!empty($CFG->themedir) and file_exists("$CFG->themedir/$themename/config.php")) {
// Alternative theme location contains this theme - ok.
} else {
header('HTTP/1.0 404 not found');
die('Theme was not found, sorry.');
}
$candidatedir = "$CFG->localcachedir/theme/$rev/$themename/css";
$candidatesheet = "{$candidatedir}/" . theme_styles_get_filename($type, $themesubrev, $usesvg);
$etag = theme_styles_get_etag($themename, $rev, $type, $themesubrev, $usesvg);
if (file_exists($candidatesheet)) {
if (!empty($_SERVER['HTTP_IF_NONE_MATCH']) || !empty($_SERVER['HTTP_IF_MODIFIED_SINCE'])) {
// We do not actually need to verify the etag value because our files
// never change in cache because we increment the rev counter.
css_send_unmodified(filemtime($candidatesheet), $etag);
}
css_send_cached_css($candidatesheet, $etag);
}
// Ok, now we need to start normal moodle script, we need to load all libs and $DB.
define('ABORT_AFTER_CONFIG_CANCEL', true);
define('NO_MOODLE_COOKIES', true); // Session not used here.
define('NO_UPGRADE_CHECK', true); // Ignore upgrade check.
require("$CFG->dirroot/lib/setup.php");
$theme = theme_config::load($themename);
$theme->force_svg_use($usesvg);
$theme->set_rtl_mode($type === 'all-rtl' ? true : false);
$themerev = theme_get_revision();
$currentthemesubrev = theme_get_sub_revision_for_theme($themename);
$cache = true;
// If the client is requesting a revision that doesn't match both
// the global theme revision and the theme specific revision then
// tell the browser not to cache this style sheet because it's
// likely being regenerated.
if ($themerev <= 0 or $themerev != $rev or $themesubrev != $currentthemesubrev) {
$rev = $themerev;
$themesubrev = $currentthemesubrev;
$cache = false;
$candidatedir = "$CFG->localcachedir/theme/$rev/$themename/css";
$candidatesheet = "{$candidatedir}/" . theme_styles_get_filename($type, $themesubrev, $usesvg);
$etag = theme_styles_get_etag($themename, $rev, $type, $themesubrev, $usesvg);
}
make_localcache_directory('theme', false);
if ($type === 'editor') {
$csscontent = $theme->get_css_content_editor();
if ($cache) {
css_store_css($theme, $candidatesheet, $csscontent);
css_send_cached_css($candidatesheet, $etag);
} else {
css_send_uncached_css($csscontent);
}
}
if (($fallbacksheet = theme_styles_fallback_content($theme)) && !$theme->has_css_cached_content()) {
// The theme is not yet available and a fallback is available.
// Return the fallback immediately, specifying the Content-Length, then generate in the background.
$css = file_get_contents($fallbacksheet);
css_send_temporary_css($css);
// The fallback content has now been sent.
// There will be an attempt to generate the content, but it should not be served.
// The Content-Length above means that the client will disregard it anyway.
$sendaftergeneration = false;
// There may be another client currently holding a lock and generating the stylesheet.
// Use a very low lock timeout as the connection will be ended immediately afterwards.
$locktimeout = 1;
} else {
// There is no fallback content to be issued here, therefore the generated content must be output.
$sendaftergeneration = true;
// Use a realistic lock timeout as the intention is to avoid lock contention.
$locktimeout = rand(90, 120);
}
// Attempt to fetch the lock.
$lockfactory = \core\lock\lock_config::get_lock_factory('core_theme_get_css_content');
$lock = $lockfactory->get_lock($themename, $locktimeout);
if ($sendaftergeneration || $lock) {
// Either the lock was successful, or the lock was unsuccessful but the content *must* be sent.
// The content does not exist locally.
// Generate and save it.
$candidatesheet = theme_styles_generate_and_store($theme, $rev, $themesubrev, $candidatedir);
if ($lock) {
$lock->release();
}
if ($sendaftergeneration) {
if (!$cache) {
// Do not pollute browser caches if invalid revision requested,
// let's ignore legacy IE breakage here too.
css_send_uncached_css(file_get_contents($candidatesheet));
} else {
// Real browsers - this is the expected result!
css_send_cached_css($candidatesheet, $etag);
}
}
}
/**
* Generate the theme CSS and store it.
*
* @param theme_config $theme The theme to be generated
* @param int $rev The theme revision
* @param int $themesubrev The theme sub-revision
* @param string $candidatedir The directory that it should be stored in
* @return string The path that the primary CSS was written to
*/
function theme_styles_generate_and_store($theme, $rev, $themesubrev, $candidatedir) {
global $CFG;
require_once("{$CFG->libdir}/filelib.php");
// Generate the content first.
if (!$csscontent = $theme->get_css_cached_content()) {
$csscontent = $theme->get_css_content();
$theme->set_css_content_cache($csscontent);
}
if ($theme->get_rtl_mode()) {
$type = "all-rtl";
} else {
$type = "all";
}
// Determine the candidatesheet path.
$candidatesheet = "{$candidatedir}/" . theme_styles_get_filename($type, $themesubrev, $theme->use_svg_icons());
// Store the CSS.
css_store_css($theme, $candidatesheet, $csscontent);
// Store the fallback CSS in the temp directory.
// This file is used as a fallback when waiting for a theme to compile and is not versioned in any way.
$fallbacksheet = make_temp_directory("theme/{$theme->name}")
. "/"
. theme_styles_get_filename($type, 0, $theme->use_svg_icons());
css_store_css($theme, $fallbacksheet, $csscontent);
// Delete older revisions from localcache.
$themecachedirs = glob("{$CFG->localcachedir}/theme/*", GLOB_ONLYDIR);
foreach ($themecachedirs as $localcachedir) {
$cachedrev = [];
preg_match("/\/theme\/([0-9]+)$/", $localcachedir, $cachedrev);
$cachedrev = isset($cachedrev[1]) ? intval($cachedrev[1]) : 0;
if ($cachedrev > 0 && $cachedrev < $rev) {
fulldelete($localcachedir);
}
}
// Delete older theme subrevision CSS from localcache.
$subrevfiles = glob("{$CFG->localcachedir}/theme/{$rev}/{$theme->name}/css/*.css");
foreach ($subrevfiles as $subrevfile) {
$cachedsubrev = [];
preg_match("/_([0-9]+)\.([0-9]+\.)?css$/", $subrevfile, $cachedsubrev);
$cachedsubrev = isset($cachedsubrev[1]) ? intval($cachedsubrev[1]) : 0;
if ($cachedsubrev > 0 && $cachedsubrev < $themesubrev) {
fulldelete($subrevfile);
}
}
return $candidatesheet;
}
/**
* Fetch the preferred fallback content location if available.
*
* @param theme_config $theme The theme to be generated
* @return string The path to the fallback sheet on disk
*/
function theme_styles_fallback_content($theme) {
global $CFG;
if (!$theme->usefallback) {
// This theme does not support fallbacks.
return false;
}
$type = $theme->get_rtl_mode() ? 'all-rtl' : 'all';
$filename = theme_styles_get_filename($type);
$fallbacksheet = "{$CFG->tempdir}/theme/{$theme->name}/{$filename}";
if (file_exists($fallbacksheet)) {
return $fallbacksheet;
}
return false;
}
/**
* Get the filename for the specified configuration.
*
* @param string $type The requested sheet type
* @param int $themesubrev The theme sub-revision
* @param bool $usesvg Whether SVGs are allowed
* @return string The filename for this sheet
*/
function theme_styles_get_filename($type, $themesubrev = 0, $usesvg = true) {
$filename = $type;
$filename .= ($themesubrev > 0) ? "_{$themesubrev}" : '';
$filename .= $usesvg ? '' : '-nosvg';
return "{$filename}.css";
}
/**
* Determine the correct etag for the specified configuration.
*
* @param string $themename The name of the theme
* @param int $rev The revision number
* @param string $type The requested sheet type
* @param int $themesubrev The theme sub-revision
* @param bool $usesvg Whether SVGs are allowed
* @return string The etag to use for this request
*/
function theme_styles_get_etag($themename, $rev, $type, $themesubrev, $usesvg) {
$etag = [$rev, $themename, $type, $themesubrev];
if (!$usesvg) {
$etag[] = 'nosvg';
}
return sha1(implode('/', $etag));
}