Update to MediaWiki 1.24.1

7 files changed, 928 insertions, 0 deletions

diff --git a/includes/title/MalformedTitleException.php b/includes/title/MalformedTitleException.php
new file mode 100644
index 00000000..a8a5d754
--- /dev/null
+++ b/includes/title/MalformedTitleException.php
@@ -0,0 +1,32 @@
+<?php
+/**
+ * Representation of a page title within %MediaWiki.
+ *
+ * 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
+ * @license GPL 2+
+ * @author Daniel Kinzler
+ */
+
+/**
+ * MalformedTitleException is thrown when a TitleParser is unable to parse a title string.
+ *
+ * @license GPL 2+
+ * @author Daniel Kinzler
+ */
+class MalformedTitleException extends Exception {
+}
diff --git a/includes/title/MediaWikiPageLinkRenderer.php b/includes/title/MediaWikiPageLinkRenderer.php
new file mode 100644
index 00000000..f46cb5e3
--- /dev/null
+++ b/includes/title/MediaWikiPageLinkRenderer.php
@@ -0,0 +1,131 @@
+<?php
+/**
+ * A service for generating links from page titles
+ *
+ * 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
+ * @license GPL 2+
+ * @author Daniel Kinzler
+ */
+
+/**
+ * A service for generating links from page titles.
+ *
+ * @see https://www.mediawiki.org/wiki/Requests_for_comment/TitleValue
+ */
+class MediaWikiPageLinkRenderer implements PageLinkRenderer {
+	/**
+	 * @var TitleFormatter
+	 */
+	protected $formatter;
+
+	/**
+	 * @var string
+	 */
+	protected $baseUrl;
+
+	/**
+	 * @note $formatter and $baseUrl are currently not used for generating links,
+	 * since we still rely on the Linker class to generate the actual HTML.
+	 * Once this is reversed so that  Linker becomes a legacy interface to
+	 * HtmlPageLinkRenderer, we will be using them, so it seems prudent to
+	 * already declare the dependency and inject them.
+	 *
+	 * @param TitleFormatter $formatter Formatter for generating the target title string
+	 * @param string $baseUrl (currently unused, pending refactoring of Linker).
+	 *        Defaults to $wgArticlePath.
+	 */
+	public function __construct( TitleFormatter $formatter, $baseUrl = null ) {
+		if ( $baseUrl === null ) {
+			$baseUrl = $GLOBALS['wgArticlePath'];
+		}
+
+		$this->formatter = $formatter;
+		$this->baseUrl = $baseUrl;
+	}
+
+	/**
+	 * Returns the (partial) URL for the given page (including any section identifier).
+	 *
+	 * @param TitleValue $page The link's target
+	 * @param array $params Any additional URL parameters.
+	 *
+	 * @return string
+	 */
+	public function getPageUrl( TitleValue $page, $params = array() ) {
+		//TODO: move the code from Linker::linkUrl here!
+		//The below is just a rough estimation!
+
+		$name = $this->formatter->getPrefixedText( $page );
+		$name = str_replace( ' ', '_', $name );
+		$name = wfUrlencode( $name );
+
+		$url = $this->baseUrl . $name;
+
+		if ( $params ) {
+			$separator = ( strpos( $url, '?' ) ) ? '&' : '?';
+			$url .= $separator . wfArrayToCgi( $params );
+		}
+
+		$fragment = $page->getFragment();
+		if ( $fragment !== '' ) {
+			$url = $url . '#' . wfUrlencode( $fragment );
+		}
+
+		return $url;
+	}
+
+	/**
+	 * Returns an HTML link to the given page, using the given surface text.
+	 *
+	 * @param TitleValue $page The link's target
+	 * @param string $text The link's surface text (will be derived from $page if not given).
+	 *
+	 * @return string
+	 */
+	public function renderHtmlLink( TitleValue $page, $text = null ) {
+		if ( $text === null ) {
+			$text = $this->formatter->getFullText( $page );
+		}
+
+		// TODO: move the logic implemented by Linker here,
+		// using $this->formatter and $this->baseUrl, and
+		// re-implement Linker to use a HtmlPageLinkRenderer.
+		$title = Title::newFromTitleValue( $page );
+		$link = Linker::link( $title, htmlspecialchars( $text ) );
+
+		return $link;
+	}
+
+	/**
+	 * Returns a wikitext link to the given page, using the given surface text.
+	 *
+	 * @param TitleValue $page The link's target
+	 * @param string $text The link's surface text (will be derived from $page if not given).
+	 *
+	 * @return string
+	 */
+	public function renderWikitextLink( TitleValue $page, $text = null ) {
+		if ( $text === null ) {
+			$text = $this->formatter->getFullText( $page );
+		}
+
+		$name = $this->formatter->getFullText( $page );
+
+		return '[[:' . $name . '|' . wfEscapeWikiText( $text ) . ']]';
+	}
+}
diff --git a/includes/title/MediaWikiTitleCodec.php b/includes/title/MediaWikiTitleCodec.php
new file mode 100644
index 00000000..6ca0799c
--- /dev/null
+++ b/includes/title/MediaWikiTitleCodec.php
@@ -0,0 +1,400 @@
+<?php
+/**
+ * A codec for %MediaWiki page titles.
+ *
+ * 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
+ * @license GPL 2+
+ * @author Daniel Kinzler
+ */
+
+/**
+ * A codec for %MediaWiki page titles.
+ *
+ * @note Normalization and validation is applied while parsing, not when formatting.
+ * It's possible to construct a TitleValue with an invalid title, and use MediaWikiTitleCodec
+ * to generate an (invalid) title string from it. TitleValues should be constructed only
+ * via parseTitle() or from a (semi)trusted source, such as the database.
+ *
+ * @see https://www.mediawiki.org/wiki/Requests_for_comment/TitleValue
+ */
+class MediaWikiTitleCodec implements TitleFormatter, TitleParser {
+	/**
+	 * @var Language
+	 */
+	protected $language;
+
+	/**
+	 * @var GenderCache
+	 */
+	protected $genderCache;
+
+	/**
+	 * @var string[]
+	 */
+	protected $localInterwikis;
+
+	/**
+	 * @param Language $language The language object to use for localizing namespace names.
+	 * @param GenderCache $genderCache The gender cache for generating gendered namespace names
+	 * @param string[]|string $localInterwikis
+	 */
+	public function __construct( Language $language, GenderCache $genderCache,
+		$localInterwikis = array()
+	) {
+		$this->language = $language;
+		$this->genderCache = $genderCache;
+		$this->localInterwikis = (array)$localInterwikis;
+	}
+
+	/**
+	 * @see TitleFormatter::getNamespaceName()
+	 *
+	 * @param int $namespace
+	 * @param string $text
+	 *
+	 * @throws InvalidArgumentException If the namespace is invalid
+	 * @return string
+	 */
+	public function getNamespaceName( $namespace, $text ) {
+		if ( $this->language->needsGenderDistinction() &&
+			MWNamespace::hasGenderDistinction( $namespace )
+		) {
+
+			//NOTE: we are assuming here that the title text is a user name!
+			$gender = $this->genderCache->getGenderOf( $text, __METHOD__ );
+			$name = $this->language->getGenderNsText( $namespace, $gender );
+		} else {
+			$name = $this->language->getNsText( $namespace );
+		}
+
+		if ( $name === false ) {
+			throw new InvalidArgumentException( 'Unknown namespace ID: ' . $namespace );
+		}
+
+		return $name;
+	}
+
+	/**
+	 * @see TitleFormatter::formatTitle()
+	 *
+	 * @param int|bool $namespace The namespace ID (or false, if the namespace should be ignored)
+	 * @param string $text The page title. Should be valid. Only minimal normalization is applied.
+	 *        Underscores will be replaced.
+	 * @param string $fragment The fragment name (may be empty).
+	 *
+	 * @throws InvalidArgumentException If the namespace is invalid
+	 * @return string
+	 */
+	public function formatTitle( $namespace, $text, $fragment = '' ) {
+		if ( $namespace !== false ) {
+			$namespace = $this->getNamespaceName( $namespace, $text );
+
+			if ( $namespace !== '' ) {
+				$text = $namespace . ':' . $text;
+			}
+		}
+
+		if ( $fragment !== '' ) {
+			$text = $text . '#' . $fragment;
+		}
+
+		$text = str_replace( '_', ' ', $text );
+
+		return $text;
+	}
+
+	/**
+	 * Parses the given text and constructs a TitleValue. Normalization
+	 * is applied according to the rules appropriate for the form specified by $form.
+	 *
+	 * @param string $text The text to parse
+	 * @param int $defaultNamespace Namespace to assume per default (usually NS_MAIN)
+	 *
+	 * @throws MalformedTitleException
+	 * @return TitleValue
+	 */
+	public function parseTitle( $text, $defaultNamespace ) {
+		// NOTE: this is an ugly cludge that allows this class to share the
+		// code for parsing with the old Title class. The parser code should
+		// be refactored to avoid this.
+		$parts = $this->splitTitleString( $text, $defaultNamespace );
+
+		// Interwiki links are not supported by TitleValue
+		if ( $parts['interwiki'] !== '' ) {
+			throw new MalformedTitleException( 'Title must not contain an interwiki prefix: ' . $text );
+		}
+
+		// Relative fragment links are not supported by TitleValue
+		if ( $parts['dbkey'] === '' ) {
+			throw new MalformedTitleException( 'Title must not be empty: ' . $text );
+		}
+
+		return new TitleValue( $parts['namespace'], $parts['dbkey'], $parts['fragment'] );
+	}
+
+	/**
+	 * @see TitleFormatter::getText()
+	 *
+	 * @param TitleValue $title
+	 *
+	 * @return string $title->getText()
+	 */
+	public function getText( TitleValue $title ) {
+		return $this->formatTitle( false, $title->getText(), '' );
+	}
+
+	/**
+	 * @see TitleFormatter::getText()
+	 *
+	 * @param TitleValue $title
+	 *
+	 * @return string
+	 */
+	public function getPrefixedText( TitleValue $title ) {
+		return $this->formatTitle( $title->getNamespace(), $title->getText(), '' );
+	}
+
+	/**
+	 * @see TitleFormatter::getText()
+	 *
+	 * @param TitleValue $title
+	 *
+	 * @return string
+	 */
+	public function getFullText( TitleValue $title ) {
+		return $this->formatTitle( $title->getNamespace(), $title->getText(), $title->getFragment() );
+	}
+
+	/**
+	 * Normalizes and splits a title string.
+	 *
+	 * This function removes illegal characters, splits off the interwiki and
+	 * namespace prefixes, sets the other forms, and canonicalizes
+	 * everything.
+	 *
+	 * @todo this method is only exposed as a temporary measure to ease refactoring.
+	 * It was copied with minimal changes from Title::secureAndSplit().
+	 *
+	 * @todo This method should be split up and an appropriate interface
+	 * defined for use by the Title class.
+	 *
+	 * @param string $text
+	 * @param int $defaultNamespace
+	 *
+	 * @throws MalformedTitleException If $text is not a valid title string.
+	 * @return array A mapp with the fields 'interwiki', 'fragment', 'namespace',
+	 *         'user_case_dbkey', and 'dbkey'.
+	 */
+	public function splitTitleString( $text, $defaultNamespace = NS_MAIN ) {
+		$dbkey = str_replace( ' ', '_', $text );
+
+		# Initialisation
+		$parts = array(
+			'interwiki' => '',
+			'local_interwiki' => false,
+			'fragment' => '',
+			'namespace' => $defaultNamespace,
+			'dbkey' => $dbkey,
+			'user_case_dbkey' => $dbkey,
+		);
+
+		# Strip Unicode bidi override characters.
+		# Sometimes they slip into cut-n-pasted page titles, where the
+		# override chars get included in list displays.
+		$dbkey = preg_replace( '/\xE2\x80[\x8E\x8F\xAA-\xAE]/S', '', $dbkey );
+
+		# Clean up whitespace
+		# Note: use of the /u option on preg_replace here will cause
+		# input with invalid UTF-8 sequences to be nullified out in PHP 5.2.x,
+		# conveniently disabling them.
+		$dbkey = preg_replace(
+			'/[ _\xA0\x{1680}\x{180E}\x{2000}-\x{200A}\x{2028}\x{2029}\x{202F}\x{205F}\x{3000}]+/u',
+			'_',
+			$dbkey
+		);
+		$dbkey = trim( $dbkey, '_' );
+
+		if ( strpos( $dbkey, UTF8_REPLACEMENT ) !== false ) {
+			# Contained illegal UTF-8 sequences or forbidden Unicode chars.
+			throw new MalformedTitleException( 'Bad UTF-8 sequences found in title: ' . $text );
+		}
+
+		$parts['dbkey'] = $dbkey;
+
+		# Initial colon indicates main namespace rather than specified default
+		# but should not create invalid {ns,title} pairs such as {0,Project:Foo}
+		if ( $dbkey !== '' && ':' == $dbkey[0] ) {
+			$parts['namespace'] = NS_MAIN;
+			$dbkey = substr( $dbkey, 1 ); # remove the colon but continue processing
+			$dbkey = trim( $dbkey, '_' ); # remove any subsequent whitespace
+		}
+
+		if ( $dbkey == '' ) {
+			throw new MalformedTitleException( 'Empty title: ' . $text );
+		}
+
+		# Namespace or interwiki prefix
+		$prefixRegexp = "/^(.+?)_*:_*(.*)$/S";
+		do {
+			$m = array();
+			if ( preg_match( $prefixRegexp, $dbkey, $m ) ) {
+				$p = $m[1];
+				if ( ( $ns = $this->language->getNsIndex( $p ) ) !== false ) {
+					# Ordinary namespace
+					$dbkey = $m[2];
+					$parts['namespace'] = $ns;
+					# For Talk:X pages, check if X has a "namespace" prefix
+					if ( $ns == NS_TALK && preg_match( $prefixRegexp, $dbkey, $x ) ) {
+						if ( $this->language->getNsIndex( $x[1] ) ) {
+							# Disallow Talk:File:x type titles...
+							throw new MalformedTitleException( 'Bad namespace prefix: ' . $text );
+						} elseif ( Interwiki::isValidInterwiki( $x[1] ) ) {
+							//TODO: get rid of global state!
+							# Disallow Talk:Interwiki:x type titles...
+							throw new MalformedTitleException( 'Interwiki prefix found in title: ' . $text );
+						}
+					}
+				} elseif ( Interwiki::isValidInterwiki( $p ) ) {
+					# Interwiki link
+					$dbkey = $m[2];
+					$parts['interwiki'] = $this->language->lc( $p );
+
+					# Redundant interwiki prefix to the local wiki
+					foreach ( $this->localInterwikis as $localIW ) {
+						if ( 0 == strcasecmp( $parts['interwiki'], $localIW ) ) {
+							if ( $dbkey == '' ) {
+								# Empty self-links should point to the Main Page, to ensure
+								# compatibility with cross-wiki transclusions and the like.
+								$mainPage = Title::newMainPage();
+								return array(
+									'interwiki' => $mainPage->getInterwiki(),
+									'local_interwiki' => true,
+									'fragment' => $mainPage->getFragment(),
+									'namespace' => $mainPage->getNamespace(),
+									'dbkey' => $mainPage->getDBkey(),
+									'user_case_dbkey' => $mainPage->getUserCaseDBKey()
+								);
+							}
+							$parts['interwiki'] = '';
+							# local interwikis should behave like initial-colon links
+							$parts['local_interwiki'] = true;
+
+							# Do another namespace split...
+							continue 2;
+						}
+					}
+
+					# If there's an initial colon after the interwiki, that also
+					# resets the default namespace
+					if ( $dbkey !== '' && $dbkey[0] == ':' ) {
+						$parts['namespace'] = NS_MAIN;
+						$dbkey = substr( $dbkey, 1 );
+					}
+				}
+				# If there's no recognized interwiki or namespace,
+				# then let the colon expression be part of the title.
+			}
+			break;
+		} while ( true );
+
+		$fragment = strstr( $dbkey, '#' );
+		if ( false !== $fragment ) {
+			$parts['fragment'] = str_replace( '_', ' ', substr( $fragment, 1 ) );
+			$dbkey = substr( $dbkey, 0, strlen( $dbkey ) - strlen( $fragment ) );
+			# remove whitespace again: prevents "Foo_bar_#"
+			# becoming "Foo_bar_"
+			$dbkey = preg_replace( '/_*$/', '', $dbkey );
+		}
+
+		# Reject illegal characters.
+		$rxTc = Title::getTitleInvalidRegex();
+		if ( preg_match( $rxTc, $dbkey ) ) {
+			throw new MalformedTitleException( 'Illegal characters found in title: ' . $text );
+		}
+
+		# Pages with "/./" or "/../" appearing in the URLs will often be un-
+		# reachable due to the way web browsers deal with 'relative' URLs.
+		# Also, they conflict with subpage syntax.  Forbid them explicitly.
+		if (
+			strpos( $dbkey, '.' ) !== false &&
+			(
+				$dbkey === '.' || $dbkey === '..' ||
+				strpos( $dbkey, './' ) === 0 ||
+				strpos( $dbkey, '../' ) === 0 ||
+				strpos( $dbkey, '/./' ) !== false ||
+				strpos( $dbkey, '/../' ) !== false ||
+				substr( $dbkey, -2 ) == '/.' ||
+				substr( $dbkey, -3 ) == '/..'
+			)
+		) {
+			throw new MalformedTitleException( 'Bad title: ' . $text );
+		}
+
+		# Magic tilde sequences? Nu-uh!
+		if ( strpos( $dbkey, '~~~' ) !== false ) {
+			throw new MalformedTitleException( 'Bad title: ' . $text );
+		}
+
+		# Limit the size of titles to 255 bytes. This is typically the size of the
+		# underlying database field. We make an exception for special pages, which
+		# don't need to be stored in the database, and may edge over 255 bytes due
+		# to subpage syntax for long titles, e.g. [[Special:Block/Long name]]
+		if (
+			( $parts['namespace'] != NS_SPECIAL && strlen( $dbkey ) > 255 )
+			|| strlen( $dbkey ) > 512
+		) {
+			throw new MalformedTitleException( 'Title too long: ' . substr( $dbkey, 0, 255 ) . '...' );
+		}
+
+		# Normally, all wiki links are forced to have an initial capital letter so [[foo]]
+		# and [[Foo]] point to the same place.  Don't force it for interwikis, since the
+		# other site might be case-sensitive.
+		$parts['user_case_dbkey'] = $dbkey;
+		if ( $parts['interwiki'] === '' ) {
+			$dbkey = Title::capitalize( $dbkey, $parts['namespace'] );
+		}
+
+		# Can't make a link to a namespace alone... "empty" local links can only be
+		# self-links with a fragment identifier.
+		if ( $dbkey == '' && $parts['interwiki'] === '' ) {
+			if ( $parts['namespace'] != NS_MAIN ) {
+				throw new MalformedTitleException( 'Empty title: ' . $text );
+			}
+		}
+
+		// Allow IPv6 usernames to start with '::' by canonicalizing IPv6 titles.
+		// IP names are not allowed for accounts, and can only be referring to
+		// edits from the IP. Given '::' abbreviations and caps/lowercaps,
+		// there are numerous ways to present the same IP. Having sp:contribs scan
+		// them all is silly and having some show the edits and others not is
+		// inconsistent. Same for talk/userpages. Keep them normalized instead.
+		if ( $parts['namespace'] == NS_USER || $parts['namespace'] == NS_USER_TALK ) {
+			$dbkey = IP::sanitizeIP( $dbkey );
+		}
+
+		// Any remaining initial :s are illegal.
+		if ( $dbkey !== '' && ':' == $dbkey[0] ) {
+			throw new MalformedTitleException( 'Title must not start with a colon: ' . $text );
+		}
+
+		# Fill fields
+		$parts['dbkey'] = $dbkey;
+
+		return $parts;
+	}
+}
diff --git a/includes/title/PageLinkRenderer.php b/includes/title/PageLinkRenderer.php
new file mode 100644
index 00000000..fb1096e0
--- /dev/null
+++ b/includes/title/PageLinkRenderer.php
@@ -0,0 +1,67 @@
+<?php
+/**
+ * Represents a link rendering service for %MediaWiki.
+ *
+ * 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
+ * @license GPL 2+
+ * @author Daniel Kinzler
+ */
+
+/**
+ * Represents a link rendering service for %MediaWiki.
+ *
+ * This is designed to encapsulate the knowledge about how page titles map to
+ * URLs, and how links are encoded in a given output format.
+ *
+ * @see https://www.mediawiki.org/wiki/Requests_for_comment/TitleValue
+ */
+interface PageLinkRenderer {
+	/**
+	 * Returns the URL for the given page.
+	 *
+	 * @todo expand this to cover the functionality of Linker::linkUrl
+	 *
+	 * @param TitleValue $page The link's target
+	 * @param array $params Any additional URL parameters.
+	 *
+	 * @return string
+	 */
+	public function getPageUrl( TitleValue $page, $params = array() );
+
+	/**
+	 * Returns an HTML link to the given page, using the given surface text.
+	 *
+	 * @todo expand this to cover the functionality of Linker::link
+	 *
+	 * @param TitleValue $page The link's target
+	 * @param string $text The link's surface text (will be derived from $page if not given).
+	 *
+	 * @return string
+	 */
+	public function renderHtmlLink( TitleValue $page, $text = null );
+
+	/**
+	 * Returns a wikitext link to the given page, using the given surface text.
+	 *
+	 * @param TitleValue $page The link's target
+	 * @param string $text The link's surface text (will be derived from $page if not given).
+	 *
+	 * @return string
+	 */
+	public function renderWikitextLink( TitleValue $page, $text = null );
+}
diff --git a/includes/title/TitleFormatter.php b/includes/title/TitleFormatter.php
new file mode 100644
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--- /dev/null
+++ b/includes/title/TitleFormatter.php
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+<?php
+/**
+ * A title formatter service for %MediaWiki.
+ *
+ * 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
+ * @license GPL 2+
+ * @author Daniel Kinzler
+ */
+
+/**
+ * A title formatter service for MediaWiki.
+ *
+ * This is designed to encapsulate knowledge about conventions for the title
+ * forms to be used in the database, in urls, in wikitext, etc.
+ *
+ * @see https://www.mediawiki.org/wiki/Requests_for_comment/TitleValue
+ */
+interface TitleFormatter {
+	/**
+	 * Returns the title formatted for display.
+	 * Per default, this includes the namespace but not the fragment.
+	 *
+	 * @note Normalization is applied if $title is not in TitleValue::TITLE_FORM.
+	 *
+	 * @param int|bool $namespace The namespace ID (or false, if the namespace should be ignored)
+	 * @param string $text The page title
+	 * @param string $fragment The fragment name (may be empty).
+	 *
+	 * @return string
+	 */
+	public function formatTitle( $namespace, $text, $fragment = '' );
+
+	/**
+	 * Returns the title text formatted for display, without namespace of fragment.
+	 *
+	 * @note Only minimal normalization is applied. Consider using TitleValue::getText() directly.
+	 *
+	 * @param TitleValue $title The title to format
+	 *
+	 * @return string
+	 */
+	public function getText( TitleValue $title );
+
+	/**
+	 * Returns the title formatted for display, including the namespace name.
+	 *
+	 * @param TitleValue $title The title to format
+	 *
+	 * @return string
+	 */
+	public function getPrefixedText( TitleValue $title );
+
+	/**
+	 * Returns the title formatted for display, with namespace and fragment.
+	 *
+	 * @param TitleValue $title The title to format
+	 *
+	 * @return string
+	 */
+	public function getFullText( TitleValue $title );
+
+	/**
+	 * Returns the name of the namespace for the given title.
+	 *
+	 * @note This must take into account gender sensitive namespace names.
+	 * @todo Move this to a separate interface
+	 *
+	 * @param int $namespace
+	 * @param string $text
+	 *
+	 * @throws InvalidArgumentException
+	 * @return string
+	 */
+	public function getNamespaceName( $namespace, $text );
+}
diff --git a/includes/title/TitleParser.php b/includes/title/TitleParser.php
new file mode 100644
index 00000000..0635ee86
--- /dev/null
+++ b/includes/title/TitleParser.php
@@ -0,0 +1,47 @@
+<?php
+/**
+ * A title parser service for %MediaWiki.
+ *
+ * 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
+ * @license GPL 2+
+ * @author Daniel Kinzler
+ */
+
+/**
+ * A title parser service for %MediaWiki.
+ *
+ * This is designed to encapsulate knowledge about conventions for the title
+ * forms to be used in the database, in urls, in wikitext, etc.
+ *
+ * @see https://www.mediawiki.org/wiki/Requests_for_comment/TitleValue
+ */
+interface TitleParser {
+	/**
+	 * Parses the given text and constructs a TitleValue. Normalization
+	 * is applied according to the rules appropriate for the form specified by $form.
+	 *
+	 * @note this only parses local page links, interwiki-prefixes etc. are not considered!
+	 *
+	 * @param string $text The text to parse
+	 * @param int $defaultNamespace Namespace to assume per default (usually NS_MAIN)
+	 *
+	 * @throws MalformedTitleException If the text is not a valid representation of a page title.
+	 * @return TitleValue
+	 */
+	public function parseTitle( $text, $defaultNamespace );
+}
diff --git a/includes/title/TitleValue.php b/includes/title/TitleValue.php
new file mode 100644
index 00000000..402247c2
--- /dev/null
+++ b/includes/title/TitleValue.php
@@ -0,0 +1,161 @@
+<?php
+/**
+ * Representation of a page title within %MediaWiki.
+ *
+ * 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
+ * @license GPL 2+
+ * @author Daniel Kinzler
+ */
+
+/**
+ * Represents a page (or page fragment) title within %MediaWiki.
+ *
+ * @note In contrast to Title, this is designed to be a plain value object. That is,
+ * it is immutable, does not use global state, and causes no side effects.
+ *
+ * @note TitleValue represents the title of a local page (or fragment of a page).
+ * It does not represent a link, and does not support interwiki prefixes etc.
+ *
+ * @see https://www.mediawiki.org/wiki/Requests_for_comment/TitleValue
+ */
+class TitleValue {
+	/**
+	 * @var int
+	 */
+	protected $namespace;
+
+	/**
+	 * @var string
+	 */
+	protected $dbkey;
+
+	/**
+	 * @var string
+	 */
+	protected $fragment;
+
+	/**
+	 * Constructs a TitleValue.
+	 *
+	 * @note TitleValue expects a valid DB key; typically, a TitleValue is constructed either
+	 * from a database entry, or by a TitleParser. We could apply "some" normalization here,
+	 * such as substituting spaces by underscores, but that would encourage the use of
+	 * un-normalized text when constructing TitleValues. For constructing a TitleValue from
+	 * user input or external sources, use a TitleParser.
+	 *
+	 * @param int $namespace The namespace ID. This is not validated.
+	 * @param string $dbkey The page title in valid DBkey form. No normalization is applied.
+	 * @param string $fragment The fragment title. Use '' to represent the whole page.
+	 *   No validation or normalization is applied.
+	 *
+	 * @throws InvalidArgumentException
+	 */
+	public function __construct( $namespace, $dbkey, $fragment = '' ) {
+		if ( !is_int( $namespace ) ) {
+			throw new InvalidArgumentException( '$namespace must be an integer' );
+		}
+
+		if ( !is_string( $dbkey ) ) {
+			throw new InvalidArgumentException( '$dbkey must be a string' );
+		}
+
+		// Sanity check, no full validation or normalization applied here!
+		if ( preg_match( '/^_|[ \r\n\t]|_$/', $dbkey ) ) {
+			throw new InvalidArgumentException( '$dbkey must be a valid DB key: ' . $dbkey );
+		}
+
+		if ( !is_string( $fragment ) ) {
+			throw new InvalidArgumentException( '$fragment must be a string' );
+		}
+
+		if ( $dbkey === '' ) {
+			throw new InvalidArgumentException( '$dbkey must not be empty' );
+		}
+
+		$this->namespace = $namespace;
+		$this->dbkey = $dbkey;
+		$this->fragment = $fragment;
+	}
+
+	/**
+	 * @return int
+	 */
+	public function getNamespace() {
+		return $this->namespace;
+	}
+
+	/**
+	 * @return string
+	 */
+	public function getFragment() {
+		return $this->fragment;
+	}
+
+	/**
+	 * Returns the title's DB key, as supplied to the constructor,
+	 * without namespace prefix or fragment.
+	 *
+	 * @return string
+	 */
+	public function getDBkey() {
+		return $this->dbkey;
+	}
+
+	/**
+	 * Returns the title in text form,
+	 * without namespace prefix or fragment.
+	 *
+	 * This is computed from the DB key by replacing any underscores with spaces.
+	 *
+	 * @note To get a title string that includes the namespace and/or fragment,
+	 *       use a TitleFormatter.
+	 *
+	 * @return string
+	 */
+	public function getText() {
+		return str_replace( '_', ' ', $this->getDBkey() );
+	}
+
+	/**
+	 * Creates a new TitleValue for a different fragment of the same page.
+	 *
+	 * @param string $fragment The fragment name, or "" for the entire page.
+	 *
+	 * @return TitleValue
+	 */
+	public function createFragmentTitle( $fragment ) {
+		return new TitleValue( $this->namespace, $this->dbkey, $fragment );
+	}
+
+	/**
+	 * Returns a string representation of the title, for logging. This is purely informative
+	 * and must not be used programmatically. Use the appropriate TitleFormatter to generate
+	 * the correct string representation for a given use.
+	 *
+	 * @return string
+	 */
+	public function __toString() {
+		$name = $this->namespace . ':' . $this->dbkey;
+
+		if ( $this->fragment !== '' ) {
+			$name .= '#' . $this->fragment;
+		}
+
+		return $name;
+	}
+}