SpecialMostGloballyLinkedFiles.php

<?php
/**
 * Special page to list files with most global usages
 *
 * @file
 * @ingroup SpecialPage
 * @author Brian Wolff <bawolff+wn@gmail.com>
 */

class MostGloballyLinkedFilesPage extends MostimagesPage {

	function __construct( $name = 'MostGloballyLinkedFiles' ) {
		parent::__construct( $name );
	}

	/**
	 * Main execution function. Use the parent if we're on the right wiki.
	 * If we're not on a shared repo, try to redirect there.
	 */
	function execute( $par ) {
		global $wgGlobalUsageSharedRepoWiki;
		if ( GlobalUsage::onSharedRepo() ) {
			parent::execute( $par );
		} else {
			GlobalUsage::redirectSpecialPageToSharedRepo( $this->getContext() );
		}
	}

	/**
	 * Don't want to do cached handling on non-shared repo, since we only redirect.
	 * @return boolean
	 */
	function isCacheable() {
		return GlobalUsage::onSharedRepo();
	}

	/**
	 * What query to do.
	 * @return array
	 */
	function getQueryInfo() {
		$this->assertOnSharedRepo();
		return array(
			'tables' => array( 'globalimagelinks' ),
			'fields' => array(
				'namespace' => NS_FILE,
				'title' => 'gil_to',
				'value' => 'COUNT(*)'
			),
			'options' => array(
				'GROUP BY' => 'gil_to',
				'HAVING' => 'COUNT(*) > 1'
			)
		);
	}

	/**
	 * Make sure we are on the shared repo.
	 *
	 * This function should only be used as a paranoia check, and should never actually be hit.
	 * There should be actual error handling for any code path a user could hit.
	 */
	protected function assertOnSharedRepo() {
		if ( !GlobalUsage::onSharedRepo() ) {
			throw new Exception( "Special:MostGloballyLinkedFiles should only be processed on the shared repo" );
		}
	}

	/**
	 * Only list this special page on the wiki that is the shared repo.
	 *
	 * @return boolean Should this be listed in Special:SpecialPages
	 */
	function isListed() {
		return GlobalUsage::onSharedRepo();
	}

	/**
	 * In most common configs (including WMF's), this wouldn't be needed. However
	 * for completeness support having the shared repo db be separate from the
	 * globalimagelinks db.
	 */
	function getRecacheDB() {
		global $wgGlobalUsageDatabase;

		// There's no reason why we couldn't make this special page work on all wikis,
		// it just doesn't really make sense to. We should be prevented from getting
		// to this point by $this->isCachable(), but just to be safe:
		$this->assertOnSharedRepo();

		if ( $wgGlobalUsageDatabase === false || $wgGlobalUsageDatabase === wfWikiID() ) {
			// We are using the local wiki
			return parent::getRecacheDB();
		} else {
			// The global usage db could be on a different db
			return wfGetDB(
				DB_SLAVE,
				array( $this->getName(), 'QueryPage::recache', 'vslow' ),
				$wgGlobalUsageDatabase
			);
		}
	}
}