Move Article checkLastModified() up to MediaWiki::performRequest

This lets revalidations via IMS headers run a bit faster.

Change-Id: I1f61086dea4c6bc460f6249ed7fda78316117a8d

includes/MediaWiki.php

@@ -286,6 +286,16 @@ class MediaWiki {
 				// may still be a wikipage redirect to another article or URL.
 				$article = $this->initializeArticle();
 				if ( is_object( $article ) ) {
+					$url = $request->getFullRequestURL(); // requested URL
+					if (
+						$request->getMethod() === 'GET' &&
+						$url === $article->getTitle()->getCanonicalURL() &&
+						$article->checkTouched() &&
+						$output->checkLastModified( $article->getTouched() )
+					) {
+						wfDebug( __METHOD__ . ": done 304\n" );
+						return;
+					}
 					$this->performAction( $article, $requestTitle );
 				} elseif ( is_string( $article ) ) {
 					$output->redirect( $article );

includes/page/Article.php

@@ -543,13 +543,8 @@ class Article implements Page {
 				}
 			}
 
-			# Is it client cached?
-			if ( $outputPage->checkLastModified( $timestamp ) ) {
-				wfDebug( __METHOD__ . ": done 304\n" );
-
-				return;
-			# Try file cache
-			} elseif ( $wgUseFileCache && $this->tryFileCache() ) {
+			# Try to stream the output from file cache
+			if ( $wgUseFileCache && $this->tryFileCache() ) {
 				wfDebug( __METHOD__ . ": done file cache\n" );
 				# tell wgOut that output is taken care of
 				$outputPage->disable();

includes/page/WikiPage.php

@@ -504,13 +504,13 @@ class WikiPage implements Page, IDBAccessObject {
 
 	/**
 	 * Loads page_touched and returns a value indicating if it should be used
-	 * @return bool True if not a redirect
+	 * @return bool True if this page exists and is not a redirect
 	 */
 	public function checkTouched() {
 		if ( !$this->mDataLoaded ) {
 			$this->loadPageData();
 		}
-		return !$this->mIsRedirect;
+		return ( $this->mId && !$this->mIsRedirect );
 	}
 
 	/**