Add Special:ListDuplicatedFiles expensive query special page.

I saw some comments recently on commons suggesting that
better ways are needed to manage duplicate files (There are tools
for if a specific file is a duplicate, but no backlog of
outstanding duplicate files).

This seems like a fairly easy first step in that direction.

Wasn't sure if this should be an image gallery type
query page, or just a list. I think in this case a plain
list is more useful.

Change-Id: Ibe4b9da71ca6451ec4e6b0050feaf3ca70e1b888

includes/AutoLoader.php

@@ -953,6 +953,7 @@ $wgAutoloadLocalClasses = array(
 	'IPBlockForm' => 'includes/specials/SpecialBlock.php',
 	'LinkSearchPage' => 'includes/specials/SpecialLinkSearch.php',
 	'ListredirectsPage' => 'includes/specials/SpecialListredirects.php',
+	'ListDuplicatedFilesPage' => 'includes/specials/SpecialListDuplicatedFiles.php',
 	'LoginForm' => 'includes/specials/SpecialUserlogin.php',
 	'LonelyPagesPage' => 'includes/specials/SpecialLonelypages.php',
 	'LongPagesPage' => 'includes/specials/SpecialLongpages.php',

includes/QueryPage.php

@@ -77,6 +77,7 @@ abstract class QueryPage extends SpecialPage {
 				array( 'DeadendPagesPage', 'Deadendpages' ),
 				array( 'DoubleRedirectsPage', 'DoubleRedirects' ),
 				array( 'FileDuplicateSearchPage', 'FileDuplicateSearch' ),
+				array( 'ListDuplicatedFilesPage', 'ListDuplicatedFiles'),
 				array( 'LinkSearchPage', 'LinkSearch' ),
 				array( 'ListredirectsPage', 'Listredirects' ),
 				array( 'LonelyPagesPage', 'Lonelypages' ),

includes/specialpage/SpecialPageFactory.php

@@ -117,6 +117,7 @@ class SpecialPageFactory {
 		'FileDuplicateSearch'       => 'FileDuplicateSearchPage',
 		'Upload'                    => 'SpecialUpload',
 		'UploadStash'               => 'SpecialUploadStash',
+		'ListDuplicatedFiles'       => 'ListDuplicatedFilesPage',
 
 		// Data and tools
 		'Statistics'                => 'SpecialStatistics',

includes/specials/SpecialListDuplicatedFiles.php

@@ -0,0 +1,112 @@
+<?php
+/**
+ * Implements Special:ListDuplicatedFiles
+ *
+ * Copyright © 2013 Brian Wolff
+ *
+ * This program 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 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ * @ingroup SpecialPage
+ * @author Brian Wolff
+ */
+
+/**
+ * Special:ListDuplicatedFiles Lists all files where the current version is
+ *   a duplicate of the current version of some other file.
+ * @ingroup SpecialPage
+ */
+class ListDuplicatedFilesPage extends QueryPage {
+	function __construct( $name = 'ListDuplicatedFiles' ) {
+		parent::__construct( $name );
+	}
+
+	function isExpensive() {
+		return true;
+	}
+
+	function isSyndicated() {
+		return false;
+	}
+
+	/**
+	 * Get all the duplicates by grouping on sha1s.
+	 *
+	 * A cheaper (but less useful) version of this
+	 * query would be to not care how many duplicates a
+	 * particular file has, and do a self-join on image table.
+	 * However this version should be no more expensive then
+	 * Special:MostLinked, which seems to get handled fine
+	 * with however we are doing cached special pages.
+	 */
+	function getQueryInfo() {
+		return array(
+			'tables' => array( 'image' ),
+			'fields' => array(
+				'namespace' => NS_FILE,
+				'title' => 'MIN(img_name)',
+				'value' => 'count(*)'
+			),
+			'options' => array(
+				'GROUP BY' => 'img_sha1',
+				'HAVING' => 'count(*) > 1',
+			),
+		);
+	}
+
+	/**
+	 * Pre-fill the link cache
+	 *
+	 * @param DatabaseBase $db
+	 * @param ResultWrapper $res
+	 */
+	function preprocessResults( $db, $res ) {
+		if ( $res->numRows() > 0 ) {
+			$linkBatch = new LinkBatch();
+
+			foreach ( $res as $row ) {
+				$linkBatch->add( $row->namespace, $row->title );
+			}
+
+			$res->seek( 0 );
+			$linkBatch->execute();
+		}
+	}
+
+
+	/**
+	 * @param Skin $skin
+	 * @param object $result Result row
+	 * @return string
+	 */
+	function formatResult( $skin, $result ) {
+		// Future version might include a list of the first 5 duplicates
+		// perhaps separated by an "↔".
+		$image1 = Title::makeTitle( $result->namespace, $result->title );
+		$dupeSearch = SpecialPage::getTitleFor( 'FileDuplicateSearch', $image1->getDBKey() );
+
+		$msg = wfMessage( 'listduplicatedfiles-entry' )
+			->params( $image1->getText() )
+			->numParams( $result->value - 1 )
+			->params( $dupeSearch->getPrefixedDBKey() );
+
+		return $msg->parse();
+	}
+
+	protected function getGroupName() {
+		return 'media';
+	}
+}

languages/messages/MessagesEn.php

@@ -423,6 +423,7 @@ $specialPageAliases = array(
 	'Listfiles'                 => array( 'ListFiles', 'FileList', 'ImageList' ),
 	'Listgrouprights'           => array( 'ListGroupRights', 'UserGroupRights' ),
 	'Listredirects'             => array( 'ListRedirects' ),
+	'ListDuplicatedFiles'       => array( 'ListDuplicatedFiles', 'ListFileDuplicates' ),
 	'Listusers'                 => array( 'ListUsers', 'UserList' ),
 	'Lockdb'                    => array( 'LockDB' ),
 	'Log'                       => array( 'Log', 'Logs' ),
@@ -2641,6 +2642,10 @@ Input: contenttype/subtype, e.g. <code>image/jpeg</code>.',
 'listredirects'         => 'List of redirects',
 'listredirects-summary' => '', # do not translate or duplicate this message to other languages
 
+'listduplicatedfiles' => 'List of files with duplicates',
+'listduplicatedfiles-summary' => 'This is a list of files where the most recent version of the file is a duplicate of the most recent version of some other file. Only local files are considered.',
+'listduplicatedfiles-entry' => '[[:File:$1|$1]] has [[$3|{{PLURAL:$2|a duplicate|$2 duplicates}}]].',
+
 # Unused templates
 'unusedtemplates'         => 'Unused templates',
 'unusedtemplates-summary' => '', # do not translate or duplicate this message to other languages

languages/messages/MessagesQqq.php

@@ -4895,6 +4895,11 @@ See also:
 # List redirects
 'listredirects' => '{{doc-special|ListRedirects}}',
 
+# List duplicates
+'listduplicatedfiles' => '{{doc-special|ListDuplicatedFiles}}',
+'listduplicatedfiles-summary' => 'Summary at top of Special:ListDuplicatedFiles',
+'listduplicatedfiles-entry' => 'A list item on Special:ListDuplicatedFiles. $1 is the file name (no namespace prefix). $2 is the number of duplicates this file has. $3 is the name of the duplicate search page (aka "Special:FileDuplicateSearch/Foo.png" or "Spécial:Recherche_fichier_en_double/Firefox.png")',
+
 # Unused templates
 'unusedtemplates' => '{{doc-special|UnusedTemplates}}',
 'unusedtemplatestext' => 'Shown on top of [[Special:Unusedtemplates]]',

maintenance/language/messages.inc

@@ -1690,6 +1690,11 @@ $wgMessageStructure = array(
 		'listredirects',
 		'listredirects-summary',
 	),
+	'listduplicatedfiles' => array(
+		'listduplicatedfiles',
+		'listduplicatedfiles-summary',
+		'listduplicatedfiles-entry',
+	),
 	'unusedtemplates' => array(
 		'unusedtemplates',
 		'unusedtemplates-summary',
@@ -4103,6 +4108,7 @@ future releases. Also note that since each list value is wrapped in a unique
 	'filedelete' => 'File deletion',
 	'mimesearch' => 'MIME search',
 	'unwatchedpages' => 'Unwatched pages',
+	'listduplicatedfiles' => 'List duplicated files special page',
 	'listredirects' => 'List redirects',
 	'unusedtemplates' => 'Unused templates',
 	'randompage' => 'Random page',