X-Git-Url: https://scripts.mit.edu/gitweb/autoinstallsdev/mediawiki.git/blobdiff_plain/19e297c21b10b1b8a3acad5e73fc71dcb35db44a..6932310fd58ebef145fa01eb76edf7150284d8ea:/includes/Category.php

diff --git a/includes/Category.php b/includes/Category.php
index 614933ff..629962d2 100644
--- a/includes/Category.php
+++ b/includes/Category.php
@@ -1,44 +1,73 @@
 <?php
 /**
- * Category objects are immutable, strictly speaking. If you call methods that change the database,
- * like to refresh link counts, the objects will be appropriately reinitialized.
- * Member variables are lazy-initialized.
+ * Representation for a category.
+ *
+ * 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.
  *
- * TODO: Move some stuff from CategoryPage.php to here, and use that.
+ * 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
  * @author Simetrical
  */
 
+/**
+ * Category objects are immutable, strictly speaking. If you call methods that change the database,
+ * like to refresh link counts, the objects will be appropriately reinitialized.
+ * Member variables are lazy-initialized.
+ *
+ * @todo Move some stuff from CategoryPage.php to here, and use that.
+ */
 class Category {
 	/** Name of the category, normalized to DB-key form */
 	private $mName = null;
 	private $mID = null;
-	/** Category page title */
+	/**
+	 * Category page title
+	 * @var Title
+	 */
 	private $mTitle = null;
 	/** Counts of membership (cat_pages, cat_subcats, cat_files) */
 	private $mPages = null, $mSubcats = null, $mFiles = null;
 
-	private function __construct() { }
+	const LOAD_ONLY = 0;
+	const LAZY_INIT_ROW = 1;
+
+	private function __construct() {
+	}
 
 	/**
 	 * Set up all member variables using a database query.
+	 * @param int $mode
+	 * @throws MWException
 	 * @return bool True on success, false on failure.
 	 */
-	protected function initialize() {
+	protected function initialize( $mode = self::LOAD_ONLY ) {
 		if ( $this->mName === null && $this->mID === null ) {
 			throw new MWException( __METHOD__ . ' has both names and IDs null' );
 		} elseif ( $this->mID === null ) {
-			$where = array( 'cat_title' => $this->mName );
+			$where = [ 'cat_title' => $this->mName ];
 		} elseif ( $this->mName === null ) {
-			$where = array( 'cat_id' => $this->mID );
+			$where = [ 'cat_id' => $this->mID ];
 		} else {
 			# Already initialized
 			return true;
 		}
-		$dbr = wfGetDB( DB_SLAVE );
+
+		$dbr = wfGetDB( DB_REPLICA );
 		$row = $dbr->selectRow(
 			'category',
-			array( 'cat_id', 'cat_title', 'cat_pages', 'cat_subcats', 'cat_files' ),
+			[ 'cat_id', 'cat_title', 'cat_pages', 'cat_subcats', 'cat_files' ],
 			$where,
 			__METHOD__
 		);
@@ -46,12 +75,18 @@ class Category {
 		if ( !$row ) {
 			# Okay, there were no contents.  Nothing to initialize.
 			if ( $this->mTitle ) {
-				# If there is a title object but no record in the category table, treat this as an empty category
-				$this->mID      = false;
-				$this->mName    = $this->mTitle->getDBkey();
-				$this->mPages   = 0;
+				# If there is a title object but no record in the category table,
+				# treat this as an empty category.
+				$this->mID = false;
+				$this->mName = $this->mTitle->getDBkey();
+				$this->mPages = 0;
 				$this->mSubcats = 0;
-				$this->mFiles   = 0;
+				$this->mFiles = 0;
+
+				# If the title exists, call refreshCounts to add a row for it.
+				if ( $mode === self::LAZY_INIT_ROW && $this->mTitle->exists() ) {
+					DeferredUpdates::addCallableUpdate( [ $this, 'refreshCounts' ] );
+				}
 
 				return true;
 			} else {
@@ -59,17 +94,23 @@ class Category {
 			}
 		}
 
-		$this->mID      = $row->cat_id;
-		$this->mName    = $row->cat_title;
-		$this->mPages   = $row->cat_pages;
+		$this->mID = $row->cat_id;
+		$this->mName = $row->cat_title;
+		$this->mPages = $row->cat_pages;
 		$this->mSubcats = $row->cat_subcats;
-		$this->mFiles   = $row->cat_files;
+		$this->mFiles = $row->cat_files;
 
-		# (bug 13683) If the count is negative, then 1) it's obviously wrong
+		# (T15683) If the count is negative, then 1) it's obviously wrong
 		# and should not be kept, and 2) we *probably* don't have to scan many
 		# rows to obtain the correct figure, so let's risk a one-time recount.
 		if ( $this->mPages < 0 || $this->mSubcats < 0 || $this->mFiles < 0 ) {
-			$this->refreshCounts();
+			$this->mPages = max( $this->mPages, 0 );
+			$this->mSubcats = max( $this->mSubcats, 0 );
+			$this->mFiles = max( $this->mFiles, 0 );
+
+			if ( $mode === self::LAZY_INIT_ROW ) {
+				DeferredUpdates::addCallableUpdate( [ $this, 'refreshCounts' ] );
+			}
 		}
 
 		return true;
@@ -78,7 +119,7 @@ class Category {
 	/**
 	 * Factory function.
 	 *
-	 * @param $name Array: A category name (no "Category:" prefix).  It need
+	 * @param array $name A category name (no "Category:" prefix).  It need
 	 *   not be normalized, with spaces replaced by underscores.
 	 * @return mixed Category, or false on a totally invalid name
 	 */
@@ -99,8 +140,8 @@ class Category {
 	/**
 	 * Factory function.
 	 *
-	 * @param $title Title for the category page
-	 * @return Mixed: category, or false on a totally invalid name
+	 * @param Title $title Title for the category page
+	 * @return Category|bool On a totally invalid name
 	 */
 	public static function newFromTitle( $title ) {
 		$cat = new self();
@@ -114,7 +155,7 @@ class Category {
 	/**
 	 * Factory function.
 	 *
-	 * @param $id Integer: a category id
+	 * @param int $id A category id
 	 * @return Category
 	 */
 	public static function newFromID( $id ) {
@@ -126,12 +167,14 @@ class Category {
 	/**
 	 * Factory function, for constructing a Category object from a result set
 	 *
-	 * @param $row result set row, must contain the cat_xxx fields. If the fields are null,
-	 *        the resulting Category object will represent an empty category if a title object
-	 *        was given. If the fields are null and no title was given, this method fails and returns false.
-	 * @param $title optional title object for the category represented by the given row.
-	 *        May be provided if it is already known, to avoid having to re-create a title object later.
-	 * @return Category
+	 * @param object $row Result set row, must contain the cat_xxx fields. If the
+	 *   fields are null, the resulting Category object will represent an empty
+	 *   category if a title object was given. If the fields are null and no
+	 *   title was given, this method fails and returns false.
+	 * @param Title $title Optional title object for the category represented by
+	 *   the given row. May be provided if it is already known, to avoid having
+	 *   to re-create a title object later.
+	 * @return Category|false
 	 */
 	public static function newFromRow( $row, $title = null ) {
 		$cat = new self();
@@ -139,7 +182,7 @@ class Category {
 
 		# NOTE: the row often results from a LEFT JOIN on categorylinks. This may result in
 		#       all the cat_xxx fields being null, if the category page exists, but nothing
-		#       was ever added to the category. This case should be treated linke an empty
+		#       was ever added to the category. This case should be treated link an empty
 		#       category, if possible.
 
 		if ( $row->cat_title === null ) {
@@ -148,46 +191,69 @@ class Category {
 				# but we can't know that here...
 				return false;
 			} else {
-				$cat->mName = $title->getDBkey(); # if we have a title object, fetch the category name from there
+				# if we have a title object, fetch the category name from there
+				$cat->mName = $title->getDBkey();
 			}
 
-			$cat->mID =   false;
+			$cat->mID = false;
 			$cat->mSubcats = 0;
-			$cat->mPages   = 0;
-			$cat->mFiles   = 0;
+			$cat->mPages = 0;
+			$cat->mFiles = 0;
 		} else {
-			$cat->mName    = $row->cat_title;
-			$cat->mID      = $row->cat_id;
+			$cat->mName = $row->cat_title;
+			$cat->mID = $row->cat_id;
 			$cat->mSubcats = $row->cat_subcats;
-			$cat->mPages   = $row->cat_pages;
-			$cat->mFiles   = $row->cat_files;
+			$cat->mPages = $row->cat_pages;
+			$cat->mFiles = $row->cat_files;
 		}
 
 		return $cat;
 	}
 
-	/** @return mixed DB key name, or false on failure */
-	public function getName() { return $this->getX( 'mName' ); }
+	/**
+	 * @return mixed DB key name, or false on failure
+	 */
+	public function getName() {
+		return $this->getX( 'mName' );
+	}
 
-	/** @return mixed Category ID, or false on failure */
-	public function getID() { return $this->getX( 'mID' ); }
+	/**
+	 * @return mixed Category ID, or false on failure
+	 */
+	public function getID() {
+		return $this->getX( 'mID' );
+	}
 
-	/** @return mixed Total number of member pages, or false on failure */
-	public function getPageCount() { return $this->getX( 'mPages' ); }
+	/**
+	 * @return mixed Total number of member pages, or false on failure
+	 */
+	public function getPageCount() {
+		return $this->getX( 'mPages' );
+	}
 
-	/** @return mixed Number of subcategories, or false on failure */
-	public function getSubcatCount() { return $this->getX( 'mSubcats' ); }
+	/**
+	 * @return mixed Number of subcategories, or false on failure
+	 */
+	public function getSubcatCount() {
+		return $this->getX( 'mSubcats' );
+	}
 
-	/** @return mixed Number of member files, or false on failure */
-	public function getFileCount() { return $this->getX( 'mFiles' ); }
+	/**
+	 * @return mixed Number of member files, or false on failure
+	 */
+	public function getFileCount() {
+		return $this->getX( 'mFiles' );
+	}
 
 	/**
-	 * @return mixed The Title for this category, or false on failure.
+	 * @return Title|bool Title for this category, or false on failure.
 	 */
 	public function getTitle() {
-		if ( $this->mTitle ) return $this->mTitle;
+		if ( $this->mTitle ) {
+			return $this->mTitle;
+		}
 
-		if ( !$this->initialize() ) {
+		if ( !$this->initialize( self::LAZY_INIT_ROW ) ) {
 			return false;
 		}
 
@@ -198,42 +264,48 @@ class Category {
 	/**
 	 * Fetch a TitleArray of up to $limit category members, beginning after the
 	 * category sort key $offset.
-	 * @param $limit integer
-	 * @param $offset string
-	 * @return TitleArray object for category members.
+	 * @param int|bool $limit
+	 * @param string $offset
+	 * @return TitleArray TitleArray object for category members.
 	 */
 	public function getMembers( $limit = false, $offset = '' ) {
-		$dbr = wfGetDB( DB_SLAVE );
+		$dbr = wfGetDB( DB_REPLICA );
 
-		$conds = array( 'cl_to' => $this->getName(), 'cl_from = page_id' );
-		$options = array( 'ORDER BY' => 'cl_sortkey' );
+		$conds = [ 'cl_to' => $this->getName(), 'cl_from = page_id' ];
+		$options = [ 'ORDER BY' => 'cl_sortkey' ];
 
 		if ( $limit ) {
-			$options[ 'LIMIT' ] = $limit;
+			$options['LIMIT'] = $limit;
 		}
 
 		if ( $offset !== '' ) {
 			$conds[] = 'cl_sortkey > ' . $dbr->addQuotes( $offset );
 		}
 
-		return TitleArray::newFromResult(
+		$result = TitleArray::newFromResult(
 			$dbr->select(
-				array( 'page', 'categorylinks' ),
-				array( 'page_id', 'page_namespace', 'page_title', 'page_len',
-					'page_is_redirect', 'page_latest' ),
+				[ 'page', 'categorylinks' ],
+				[ 'page_id', 'page_namespace', 'page_title', 'page_len',
+					'page_is_redirect', 'page_latest' ],
 				$conds,
 				__METHOD__,
 				$options
 			)
 		);
+
+		return $result;
 	}
 
-	/** Generic accessor */
+	/**
+	 * Generic accessor
+	 * @param string $key
+	 * @return bool
+	 */
 	private function getX( $key ) {
-		if ( !$this->initialize() ) {
+		if ( !$this->initialize( self::LAZY_INIT_ROW ) ) {
 			return false;
 		}
-		return $this-> { $key } ;
+		return $this->{$key};
 	}
 
 	/**
@@ -246,61 +318,92 @@ class Category {
 			return false;
 		}
 
-		# Note, we must use names for this, since categorylinks does.
-		if ( $this->mName === null ) {
-			if ( !$this->initialize() ) {
-				return false;
-			}
+		# If we have just a category name, find out whether there is an
+		# existing row. Or if we have just an ID, get the name, because
+		# that's what categorylinks uses.
+		if ( !$this->initialize( self::LOAD_ONLY ) ) {
+			return false;
 		}
 
 		$dbw = wfGetDB( DB_MASTER );
-		$dbw->begin();
-
-		# Insert the row if it doesn't exist yet (e.g., this is being run via
-		# update.php from a pre-1.16 schema).  TODO: This will cause lots and
-		# lots of gaps on some non-MySQL DBMSes if you run populateCategory.php
-		# repeatedly.  Plus it's an extra query that's unneeded almost all the
-		# time.  This should be rewritten somehow, probably.
-		$seqVal = $dbw->nextSequenceValue( 'category_cat_id_seq' );
-		$dbw->insert(
-			'category',
-			array(
-				'cat_id' => $seqVal,
-				'cat_title' => $this->mName
-			),
-			__METHOD__,
-			'IGNORE'
-		);
+		# Avoid excess contention on the same category (T162121)
+		$name = __METHOD__ . ':' . md5( $this->mName );
+		$scopedLock = $dbw->getScopedLockAndFlush( $name, __METHOD__, 1 );
+		if ( !$scopedLock ) {
+			return false;
+		}
 
-		$cond1 = $dbw->conditional( 'page_namespace=' . NS_CATEGORY, 1, 'NULL' );
-		$cond2 = $dbw->conditional( 'page_namespace=' . NS_FILE, 1, 'NULL' );
+		$dbw->startAtomic( __METHOD__ );
+
+		$cond1 = $dbw->conditional( [ 'page_namespace' => NS_CATEGORY ], 1, 'NULL' );
+		$cond2 = $dbw->conditional( [ 'page_namespace' => NS_FILE ], 1, 'NULL' );
 		$result = $dbw->selectRow(
-			array( 'categorylinks', 'page' ),
-			array( 'COUNT(*) AS pages',
-				   "COUNT($cond1) AS subcats",
-				   "COUNT($cond2) AS files"
-			),
-			array( 'cl_to' => $this->mName, 'page_id = cl_from' ),
+			[ 'categorylinks', 'page' ],
+			[ 'pages' => 'COUNT(*)',
+				'subcats' => "COUNT($cond1)",
+				'files' => "COUNT($cond2)"
+			],
+			[ 'cl_to' => $this->mName, 'page_id = cl_from' ],
 			__METHOD__,
-			'LOCK IN SHARE MODE'
-		);
-		$ret = $dbw->update(
-			'category',
-			array(
-				'cat_pages' => $result->pages,
-				'cat_subcats' => $result->subcats,
-				'cat_files' => $result->files
-			),
-			array( 'cat_title' => $this->mName ),
-			__METHOD__
+			[ 'LOCK IN SHARE MODE' ]
 		);
-		$dbw->commit();
+
+		$shouldExist = $result->pages > 0 || $this->getTitle()->exists();
+
+		if ( $this->mID ) {
+			if ( $shouldExist ) {
+				# The category row already exists, so do a plain UPDATE instead
+				# of INSERT...ON DUPLICATE KEY UPDATE to avoid creating a gap
+				# in the cat_id sequence. The row may or may not be "affected".
+				$dbw->update(
+					'category',
+					[
+						'cat_pages' => $result->pages,
+						'cat_subcats' => $result->subcats,
+						'cat_files' => $result->files
+					],
+					[ 'cat_title' => $this->mName ],
+					__METHOD__
+				);
+			} else {
+				# The category is empty and has no description page, delete it
+				$dbw->delete(
+					'category',
+					[ 'cat_title' => $this->mName ],
+					__METHOD__
+				);
+				$this->mID = false;
+			}
+		} elseif ( $shouldExist ) {
+			# The category row doesn't exist but should, so create it. Use
+			# upsert in case of races.
+			$dbw->upsert(
+				'category',
+				[
+					'cat_title' => $this->mName,
+					'cat_pages' => $result->pages,
+					'cat_subcats' => $result->subcats,
+					'cat_files' => $result->files
+				],
+				[ 'cat_title' ],
+				[
+					'cat_pages' => $result->pages,
+					'cat_subcats' => $result->subcats,
+					'cat_files' => $result->files
+				],
+				__METHOD__
+			);
+			// @todo: Should we update $this->mID here? Or not since Category
+			// objects tend to be short lived enough to not matter?
+		}
+
+		$dbw->endAtomic( __METHOD__ );
 
 		# Now we should update our local counts.
-		$this->mPages   = $result->pages;
+		$this->mPages = $result->pages;
 		$this->mSubcats = $result->subcats;
-		$this->mFiles   = $result->files;
+		$this->mFiles = $result->files;
 
-		return $ret;
+		return true;
 	}
 }