1 files changed, 141 insertions, 20 deletions

diff --git a/includes/PrefixSearch.php b/includes/PrefixSearch.php
index 718750f5..55a4f49b 100644
--- a/includes/PrefixSearch.php
+++ b/includes/PrefixSearch.php
@@ -34,11 +34,12 @@ abstract class PrefixSearch {
 	 * @param string $search
 	 * @param int $limit
 	 * @param array $namespaces Used if query is not explicitly prefixed
+	 * @param int $offset How many results to offset from the beginning
 	 * @return array Array of strings
 	 */
-	public static function titleSearch( $search, $limit, $namespaces = array() ) {
+	public static function titleSearch( $search, $limit, $namespaces = array(), $offset = 0 ) {
 		$prefixSearch = new StringPrefixSearch;
-		return $prefixSearch->search( $search, $limit, $namespaces );
+		return $prefixSearch->search( $search, $limit, $namespaces, $offset );
 	}
 
 	/**
@@ -47,9 +48,10 @@ abstract class PrefixSearch {
 	 * @param string $search
 	 * @param int $limit
 	 * @param array $namespaces Used if query is not explicitly prefixed
+	 * @param int $offset How many results to offset from the beginning
 	 * @return array Array of strings or Title objects
 	 */
-	public function search( $search, $limit, $namespaces = array() ) {
+	public function search( $search, $limit, $namespaces = array(), $offset = 0 ) {
 		$search = trim( $search );
 		if ( $search == '' ) {
 			return array(); // Return empty result
@@ -60,11 +62,12 @@ abstract class PrefixSearch {
 		$title = Title::newFromText( $search );
 		if ( $title && !$title->isExternal() ) {
 			$ns = array( $title->getNamespace() );
+			$search = $title->getText();
 			if ( $ns[0] == NS_MAIN ) {
 				$ns = $namespaces; // no explicit prefix, use default namespaces
+				Hooks::run( 'PrefixSearchExtractNamespace', array( &$ns, &$search ) );
 			}
-			return $this->searchBackend(
-				$ns, $title->getText(), $limit );
+			return $this->searchBackend( $ns, $search, $limit, $offset );
 		}
 
 		// Is this a namespace prefix?
@@ -75,9 +78,11 @@ abstract class PrefixSearch {
 		{
 			$namespaces = array( $title->getNamespace() );
 			$search = '';
+		} else {
+			Hooks::run( 'PrefixSearchExtractNamespace', array( &$namespaces, &$search ) );
 		}
 
-		return $this->searchBackend( $namespaces, $search, $limit );
+		return $this->searchBackend( $namespaces, $search, $limit, $offset );
 	}
 
 	/**
@@ -85,12 +90,12 @@ abstract class PrefixSearch {
 	 * @param string $search
 	 * @param int $limit
 	 * @param array $namespaces
+	 * @param int $offset How many results to offset from the beginning
 	 *
 	 * @return array
 	 */
-	public function searchWithVariants( $search, $limit, array $namespaces ) {
-		wfProfileIn( __METHOD__ );
-		$searches = $this->search( $search, $limit, $namespaces );
+	public function searchWithVariants( $search, $limit, array $namespaces, $offset = 0 ) {
+		$searches = $this->search( $search, $limit, $namespaces, $offset );
 
 		// if the content language has variants, try to retrieve fallback results
 		$fallbackLimit = $limit - count( $searches );
@@ -110,7 +115,6 @@ abstract class PrefixSearch {
 				}
 			}
 		}
-		wfProfileOut( __METHOD__ );
 		return $searches;
 	}
 
@@ -138,22 +142,128 @@ abstract class PrefixSearch {
 	 * @param array $namespaces
 	 * @param string $search
 	 * @param int $limit
+	 * @param int $offset How many results to offset from the beginning
 	 * @return array Array of strings
 	 */
-	protected function searchBackend( $namespaces, $search, $limit ) {
+	protected function searchBackend( $namespaces, $search, $limit, $offset ) {
 		if ( count( $namespaces ) == 1 ) {
 			$ns = $namespaces[0];
 			if ( $ns == NS_MEDIA ) {
 				$namespaces = array( NS_FILE );
 			} elseif ( $ns == NS_SPECIAL ) {
-				return $this->titles( $this->specialSearch( $search, $limit ) );
+				return $this->titles( $this->specialSearch( $search, $limit, $offset ) );
 			}
 		}
 		$srchres = array();
-		if ( wfRunHooks( 'PrefixSearchBackend', array( $namespaces, $search, $limit, &$srchres ) ) ) {
-			return $this->titles( $this->defaultSearchBackend( $namespaces, $search, $limit ) );
+		if ( Hooks::run(
+			'PrefixSearchBackend',
+			array( $namespaces, $search, $limit, &$srchres, $offset )
+		) ) {
+			return $this->titles( $this->defaultSearchBackend( $namespaces, $search, $limit, $offset ) );
 		}
-		return $this->strings( $srchres );
+		return $this->strings( $this->handleResultFromHook( $srchres, $namespaces, $search, $limit ) );
+	}
+
+	/**
+	 * Default search backend does proper prefix searching, but custom backends
+	 * may sort based on other algorythms that may cause the exact title match
+	 * to not be in the results or be lower down the list.
+	 * @param array $srchres results from the hook
+	 * @return array munged results from the hook
+	 */
+	private function handleResultFromHook( $srchres, $namespaces, $search, $limit ) {
+		// Pick namespace (based on PrefixSearch::defaultSearchBackend)
+		$ns = in_array( NS_MAIN, $namespaces ) ? NS_MAIN : $namespaces[0];
+		$t = Title::newFromText( $search, $ns );
+		if ( !$t || !$t->exists() ) {
+			// No exact match so just return the search results
+			return $srchres;
+		}
+		$string = $t->getPrefixedText();
+		$key = array_search( $string, $srchres );
+		if ( $key !== false ) {
+			// Exact match was in the results so just move it to the front
+			return $this->pullFront( $key, $srchres );
+		}
+		// Exact match not in the search results so check for some redirect handling cases
+		if ( $t->isRedirect() ) {
+			$target = $this->getRedirectTarget( $t );
+			$key = array_search( $target, $srchres );
+			if ( $key !== false ) {
+				// Exact match is a redirect to one of the returned matches so pull the
+				// returned match to the front.  This might look odd but the alternative
+				// is to put the redirect in front and drop the match.  The name of the
+				// found match is often more descriptive/better formed than the name of
+				// the redirect AND by definition they share a prefix.  Hopefully this
+				// choice is less confusing and more helpful.  But it might not be.  But
+				// it is the choice we're going with for now.
+				return $this->pullFront( $key, $srchres );
+			}
+			$redirectTargetsToRedirect = $this->redirectTargetsToRedirect( $srchres );
+			if ( isset( $redirectTargetsToRedirect[$target] ) ) {
+				// The exact match and something in the results list are both redirects
+				// to the same thing!  In this case we'll pull the returned match to the
+				// top following the same logic above.  Again, it might not be a perfect
+				// choice but it'll do.
+				return $this->pullFront( $redirectTargetsToRedirect[$target], $srchres );
+			}
+		} else {
+			$redirectTargetsToRedirect = $this->redirectTargetsToRedirect( $srchres );
+			if ( isset( $redirectTargetsToRedirect[$string] ) ) {
+				// The exact match is the target of a redirect already in the results list so remove
+				// the redirect from the results list and push the exact match to the front
+				array_splice( $srchres, $redirectTargetsToRedirect[$string], 1 );
+				array_unshift( $srchres, $string );
+				return $srchres;
+			}
+		}
+
+		// Exact match is totally unique from the other results so just add it to the front
+		array_unshift( $srchres, $string );
+		// And roll one off the end if the results are too long
+		if ( count( $srchres ) > $limit ) {
+			array_pop( $srchres );
+		}
+		return $srchres;
+	}
+
+	/**
+	 * @param Array(string) $titles as strings
+	 * @return Array(string => int) redirect target prefixedText to index of title in titles
+	 *   that is a redirect to it.
+	 */
+	private function redirectTargetsToRedirect( $titles ) {
+		$result = array();
+		foreach ( $titles as $key => $titleText ) {
+			$title = Title::newFromText( $titleText );
+			if ( !$title || !$title->isRedirect() ) {
+				continue;
+			}
+			$target = $this->getRedirectTarget( $title );
+			if ( !$target ) {
+				continue;
+			}
+			$result[$target] = $key;
+		}
+		return $result;
+	}
+
+	/**
+	 * @param int $key key to pull to the front
+	 * @return array $array with the item at $key pulled to the front
+	 */
+	private function pullFront( $key, $array ) {
+		$cut = array_splice( $array, $key, 1 );
+		array_unshift( $array, $cut[0] );
+		return $array;
+	}
+
+	private function getRedirectTarget( $title ) {
+		$page = WikiPage::factory( $title );
+		if ( !$page->exists() ) {
+			return null;
+		}
+		return $page->getRedirectTarget()->getPrefixedText();
 	}
 
 	/**
@@ -161,9 +271,10 @@ abstract class PrefixSearch {
 	 *
 	 * @param string $search Term
 	 * @param int $limit Max number of items to return
+	 * @param int $offset Number of items to offset
 	 * @return array
 	 */
-	protected function specialSearch( $search, $limit ) {
+	protected function specialSearch( $search, $limit, $offset ) {
 		global $wgContLang;
 
 		$searchParts = explode( '/', $search, 2 );
@@ -179,7 +290,7 @@ abstract class PrefixSearch {
 			}
 			$special = SpecialPageFactory::getPage( $specialTitle->getText() );
 			if ( $special ) {
-				$subpages = $special->prefixSearchSubpages( $subpageSearch, $limit );
+				$subpages = $special->prefixSearchSubpages( $subpageSearch, $limit, $offset );
 				return array_map( function ( $sub ) use ( $specialTitle ) {
 					return $specialTitle->getSubpage( $sub );
 				}, $subpages );
@@ -195,7 +306,7 @@ abstract class PrefixSearch {
 		// Unlike SpecialPage itself, we want the canonical forms of both
 		// canonical and alias title forms...
 		$keys = array();
-		foreach ( SpecialPageFactory::getNames() as $page  ) {
+		foreach ( SpecialPageFactory::getNames() as $page ) {
 			$keys[$wgContLang->caseFold( $page )] = $page;
 		}
 
@@ -211,12 +322,17 @@ abstract class PrefixSearch {
 		ksort( $keys );
 
 		$srchres = array();
+		$skipped = 0;
 		foreach ( $keys as $pageKey => $page ) {
 			if ( $searchKey === '' || strpos( $pageKey, $searchKey ) === 0 ) {
 				// bug 27671: Don't use SpecialPage::getTitleFor() here because it
 				// localizes its input leading to searches for e.g. Special:All
 				// returning Spezial:MediaWiki-Systemnachrichten and returning
 				// Spezial:Alle_Seiten twice when $wgLanguageCode == 'de'
+				if ( $offset > 0 && $skipped < $offset ) {
+					$skipped++;
+					continue;
+				}
 				$srchres[] = Title::makeTitleSafe( NS_SPECIAL, $page );
 			}
 
@@ -237,9 +353,10 @@ abstract class PrefixSearch {
 	 * @param array $namespaces Namespaces to search in
 	 * @param string $search Term
 	 * @param int $limit Max number of items to return
+	 * @param int $offset Number of items to skip
 	 * @return array Array of Title objects
 	 */
-	protected function defaultSearchBackend( $namespaces, $search, $limit ) {
+	protected function defaultSearchBackend( $namespaces, $search, $limit, $offset ) {
 		$ns = array_shift( $namespaces ); // support only one namespace
 		if ( in_array( NS_MAIN, $namespaces ) ) {
 			$ns = NS_MAIN; // if searching on many always default to main
@@ -255,7 +372,11 @@ abstract class PrefixSearch {
 				'page_title ' . $dbr->buildLike( $prefix, $dbr->anyString() )
 			),
 			__METHOD__,
-			array( 'LIMIT' => $limit, 'ORDER BY' => 'page_title' )
+			array(
+				'LIMIT' => $limit,
+				'ORDER BY' => 'page_title',
+				'OFFSET' => $offset
+			)
 		);
 		$srchres = array();
 		foreach ( $res as $row ) {