resourceloader: Avoid needless GPC normalisation

Utility methods like getFuzzyBool already use getRawVal instead
of getVal (see 83df6d8). But there was still direct use of getVal
which meant we still pay for WebRequest normalisation in load.php.

ResourceLoaderContext::__construct's use of WebRequest::getVal
accounts for 0.12% of execution time according to a Xenon daily log
(2016-09-27.all.reversed.svgz). The total use of WebRequest::getVal
is 0.26% of execution time. So almost half of that comes from RL.

Change-Id: Id37619ceadb5c990abf83f7910104cbc95523d28

diff --git a/includes/resourceloader/ResourceLoaderContext.php b/includes/resourceloader/ResourceLoaderContext.php
index 4a2f759..b17200f 100644 (file)
--- a/includes/resourceloader/ResourceLoaderContext.php
+++ b/includes/resourceloader/ResourceLoaderContext.php
@@ -26,7 +26,7 @@ use MediaWiki\Logger\LoggerFactory;
 
 /**
  * Object passed around to modules which contains information about the state
- * of a specific loader request
+ * of a specific loader request.
  */
 class ResourceLoaderContext {
        protected $resourceLoader;
@@ -62,26 +62,33 @@ class ResourceLoaderContext {
                $this->request = $request;
                $this->logger = $resourceLoader->getLogger();
 
+               // Future developers: Avoid use of getVal() in this class, which performs
+               // expensive UTF normalisation by default. Use getRawVal() instead.
+               // Values here are either one of a finite number of internal IDs,
+               // or previously-stored user input (e.g. titles, user names) that were passed
+               // to this endpoint by ResourceLoader itself from the canonical value.
+               // Values do not come directly from user input and need not match.
+
                // List of modules
-               $modules = $request->getVal( 'modules' );
+               $modules = $request->getRawVal( 'modules' );
                $this->modules = $modules ? self::expandModuleNames( $modules ) : [];
 
                // Various parameters
-               $this->user = $request->getVal( 'user' );
+               $this->user = $request->getRawVal( 'user' );
                $this->debug = $request->getFuzzyBool(
                        'debug',
                        $resourceLoader->getConfig()->get( 'ResourceLoaderDebug' )
                );
-               $this->only = $request->getVal( 'only', null );
-               $this->version = $request->getVal( 'version', null );
+               $this->only = $request->getRawVal( 'only', null );
+               $this->version = $request->getRawVal( 'version', null );
                $this->raw = $request->getFuzzyBool( 'raw' );
 
                // Image requests
-               $this->image = $request->getVal( 'image' );
-               $this->variant = $request->getVal( 'variant' );
-               $this->format = $request->getVal( 'format' );
+               $this->image = $request->getRawVal( 'image' );
+               $this->variant = $request->getRawVal( 'variant' );
+               $this->format = $request->getRawVal( 'format' );
 
-               $this->skin = $request->getVal( 'skin' );
+               $this->skin = $request->getRawVal( 'skin' );
                $skinnames = Skin::getSkinNames();
                // If no skin is specified, or we don't recognize the skin, use the default skin
                if ( !$this->skin || !isset( $skinnames[$this->skin] ) ) {
@@ -171,7 +178,7 @@ class ResourceLoaderContext {
                if ( $this->language === null ) {
                        // Must be a valid language code after this point (T64849)
                        // Only support uselang values that follow built-in conventions (T102058)
-                       $lang = $this->getRequest()->getVal( 'lang', '' );
+                       $lang = $this->getRequest()->getRawVal( 'lang', '' );
                        // Stricter version of RequestContext::sanitizeLangCode()
                        if ( !Language::isValidBuiltInCode( $lang ) ) {
                                wfDebug( "Invalid user language code\n" );
@@ -187,7 +194,7 @@ class ResourceLoaderContext {
         */
        public function getDirection() {
                if ( $this->direction === null ) {
-                       $this->direction = $this->getRequest()->getVal( 'dir' );
+                       $this->direction = $this->getRequest()->getRawVal( 'dir' );
                        if ( !$this->direction ) {
                                // Determine directionality based on user language (bug 6100)
                                $this->direction = Language::factory( $this->getLanguage() )->getDir();