includes/Category.php

   1 <?php
   2 /**
   3  * Representation for a category.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @author Simetrical
  22  */
  23
  24 /**
  25  * Category objects are immutable, strictly speaking. If you call methods that change the database,
  26  * like to refresh link counts, the objects will be appropriately reinitialized.
  27  * Member variables are lazy-initialized.
  28  *
  29  * @todo Move some stuff from CategoryPage.php to here, and use that.
  30  */
  31 class Category {
  32         /** Name of the category, normalized to DB-key form */
  33         private $mName = null;
  34         private $mID = null;
  35         /**
  36          * Category page title
  37          * @var Title
  38          */
  39         private $mTitle = null;
  40         /** Counts of membership (cat_pages, cat_subcats, cat_files) */
  41         private $mPages = null, $mSubcats = null, $mFiles = null;
  42
  43         private function __construct() {
  44         }
  45
  46         /**
  47          * Set up all member variables using a database query.
  48          * @throws MWException
  49          * @return bool True on success, false on failure.
  50          */
  51         protected function initialize() {
  52                 if ( $this->mName === null && $this->mID === null ) {
  53                         throw new MWException( __METHOD__ . ' has both names and IDs null' );
  54                 } elseif ( $this->mID === null ) {
  55                         $where = [ 'cat_title' => $this->mName ];
  56                 } elseif ( $this->mName === null ) {
  57                         $where = [ 'cat_id' => $this->mID ];
  58                 } else {
  59                         # Already initialized
  60                         return true;
  61                 }
  62
  63                 $dbr = wfGetDB( DB_SLAVE );
  64                 $row = $dbr->selectRow(
  65                         'category',
  66                         [ 'cat_id', 'cat_title', 'cat_pages', 'cat_subcats', 'cat_files' ],
  67                         $where,
  68                         __METHOD__
  69                 );
  70
  71                 if ( !$row ) {
  72                         # Okay, there were no contents.  Nothing to initialize.
  73                         if ( $this->mTitle ) {
  74                                 # If there is a title object but no record in the category table,
  75                                 # treat this as an empty category.
  76                                 $this->mID = false;
  77                                 $this->mName = $this->mTitle->getDBkey();
  78                                 $this->mPages = 0;
  79                                 $this->mSubcats = 0;
  80                                 $this->mFiles = 0;
  81
  82                                 return true;
  83                         } else {
  84                                 return false; # Fail
  85                         }
  86                 }
  87
  88                 $this->mID = $row->cat_id;
  89                 $this->mName = $row->cat_title;
  90                 $this->mPages = $row->cat_pages;
  91                 $this->mSubcats = $row->cat_subcats;
  92                 $this->mFiles = $row->cat_files;
  93
  94                 # (bug 13683) If the count is negative, then 1) it's obviously wrong
  95                 # and should not be kept, and 2) we *probably* don't have to scan many
  96                 # rows to obtain the correct figure, so let's risk a one-time recount.
  97                 if ( $this->mPages < 0 || $this->mSubcats < 0 || $this->mFiles < 0 ) {
  98                         $this->mPages = max( $this->mPages, 0 );
  99                         $this->mSubcats = max( $this->mSubcats, 0 );
 100                         $this->mFiles = max( $this->mFiles, 0 );
 101
 102                         DeferredUpdates::addCallableUpdate( [ $this, 'refreshCounts' ] );
 103                 }
 104
 105                 return true;
 106         }
 107
 108         /**
 109          * Factory function.
 110          *
 111          * @param array $name A category name (no "Category:" prefix).  It need
 112          *   not be normalized, with spaces replaced by underscores.
 113          * @return mixed Category, or false on a totally invalid name
 114          */
 115         public static function newFromName( $name ) {
 116                 $cat = new self();
 117                 $title = Title::makeTitleSafe( NS_CATEGORY, $name );
 118
 119                 if ( !is_object( $title ) ) {
 120                         return false;
 121                 }
 122
 123                 $cat->mTitle = $title;
 124                 $cat->mName = $title->getDBkey();
 125
 126                 return $cat;
 127         }
 128
 129         /**
 130          * Factory function.
 131          *
 132          * @param Title $title Title for the category page
 133          * @return Category|bool On a totally invalid name
 134          */
 135         public static function newFromTitle( $title ) {
 136                 $cat = new self();
 137
 138                 $cat->mTitle = $title;
 139                 $cat->mName = $title->getDBkey();
 140
 141                 return $cat;
 142         }
 143
 144         /**
 145          * Factory function.
 146          *
 147          * @param int $id A category id
 148          * @return Category
 149          */
 150         public static function newFromID( $id ) {
 151                 $cat = new self();
 152                 $cat->mID = intval( $id );
 153                 return $cat;
 154         }
 155
 156         /**
 157          * Factory function, for constructing a Category object from a result set
 158          *
 159          * @param object $row Result set row, must contain the cat_xxx fields. If the
 160          *   fields are null, the resulting Category object will represent an empty
 161          *   category if a title object was given. If the fields are null and no
 162          *   title was given, this method fails and returns false.
 163          * @param Title $title Optional title object for the category represented by
 164          *   the given row. May be provided if it is already known, to avoid having
 165          *   to re-create a title object later.
 166          * @return Category
 167          */
 168         public static function newFromRow( $row, $title = null ) {
 169                 $cat = new self();
 170                 $cat->mTitle = $title;
 171
 172                 # NOTE: the row often results from a LEFT JOIN on categorylinks. This may result in
 173                 #       all the cat_xxx fields being null, if the category page exists, but nothing
 174                 #       was ever added to the category. This case should be treated link an empty
 175                 #       category, if possible.
 176
 177                 if ( $row->cat_title === null ) {
 178                         if ( $title === null ) {
 179                                 # the name is probably somewhere in the row, for example as page_title,
 180                                 # but we can't know that here...
 181                                 return false;
 182                         } else {
 183                                 # if we have a title object, fetch the category name from there
 184                                 $cat->mName = $title->getDBkey();
 185                         }
 186
 187                         $cat->mID = false;
 188                         $cat->mSubcats = 0;
 189                         $cat->mPages = 0;
 190                         $cat->mFiles = 0;
 191                 } else {
 192                         $cat->mName = $row->cat_title;
 193                         $cat->mID = $row->cat_id;
 194                         $cat->mSubcats = $row->cat_subcats;
 195                         $cat->mPages = $row->cat_pages;
 196                         $cat->mFiles = $row->cat_files;
 197                 }
 198
 199                 return $cat;
 200         }
 201
 202         /**
 203          * @return mixed DB key name, or false on failure
 204          */
 205         public function getName() {
 206                 return $this->getX( 'mName' );
 207         }
 208
 209         /**
 210          * @return mixed Category ID, or false on failure
 211          */
 212         public function getID() {
 213                 return $this->getX( 'mID' );
 214         }
 215
 216         /**
 217          * @return mixed Total number of member pages, or false on failure
 218          */
 219         public function getPageCount() {
 220                 return $this->getX( 'mPages' );
 221         }
 222
 223         /**
 224          * @return mixed Number of subcategories, or false on failure
 225          */
 226         public function getSubcatCount() {
 227                 return $this->getX( 'mSubcats' );
 228         }
 229
 230         /**
 231          * @return mixed Number of member files, or false on failure
 232          */
 233         public function getFileCount() {
 234                 return $this->getX( 'mFiles' );
 235         }
 236
 237         /**
 238          * @return Title|bool Title for this category, or false on failure.
 239          */
 240         public function getTitle() {
 241                 if ( $this->mTitle ) {
 242                         return $this->mTitle;
 243                 }
 244
 245                 if ( !$this->initialize() ) {
 246                         return false;
 247                 }
 248
 249                 $this->mTitle = Title::makeTitleSafe( NS_CATEGORY, $this->mName );
 250                 return $this->mTitle;
 251         }
 252
 253         /**
 254          * Fetch a TitleArray of up to $limit category members, beginning after the
 255          * category sort key $offset.
 256          * @param int $limit
 257          * @param string $offset
 258          * @return TitleArray TitleArray object for category members.
 259          */
 260         public function getMembers( $limit = false, $offset = '' ) {
 261
 262                 $dbr = wfGetDB( DB_SLAVE );
 263
 264                 $conds = [ 'cl_to' => $this->getName(), 'cl_from = page_id' ];
 265                 $options = [ 'ORDER BY' => 'cl_sortkey' ];
 266
 267                 if ( $limit ) {
 268                         $options['LIMIT'] = $limit;
 269                 }
 270
 271                 if ( $offset !== '' ) {
 272                         $conds[] = 'cl_sortkey > ' . $dbr->addQuotes( $offset );
 273                 }
 274
 275                 $result = TitleArray::newFromResult(
 276                         $dbr->select(
 277                                 [ 'page', 'categorylinks' ],
 278                                 [ 'page_id', 'page_namespace', 'page_title', 'page_len',
 279                                         'page_is_redirect', 'page_latest' ],
 280                                 $conds,
 281                                 __METHOD__,
 282                                 $options
 283                         )
 284                 );
 285
 286                 return $result;
 287         }
 288
 289         /**
 290          * Generic accessor
 291          * @param string $key
 292          * @return bool
 293          */
 294         private function getX( $key ) {
 295                 if ( !$this->initialize() ) {
 296                         return false;
 297                 }
 298                 return $this->{$key};
 299         }
 300
 301         /**
 302          * Refresh the counts for this category.
 303          *
 304          * @return bool True on success, false on failure
 305          */
 306         public function refreshCounts() {
 307                 if ( wfReadOnly() ) {
 308                         return false;
 309                 }
 310
 311                 # If we have just a category name, find out whether there is an
 312                 # existing row. Or if we have just an ID, get the name, because
 313                 # that's what categorylinks uses.
 314                 if ( !$this->initialize() ) {
 315                         return false;
 316                 }
 317
 318                 $dbw = wfGetDB( DB_MASTER );
 319                 $dbw->startAtomic( __METHOD__ );
 320
 321                 $cond1 = $dbw->conditional( [ 'page_namespace' => NS_CATEGORY ], 1, 'NULL' );
 322                 $cond2 = $dbw->conditional( [ 'page_namespace' => NS_FILE ], 1, 'NULL' );
 323                 $result = $dbw->selectRow(
 324                         [ 'categorylinks', 'page' ],
 325                         [ 'pages' => 'COUNT(*)',
 326                                 'subcats' => "COUNT($cond1)",
 327                                 'files' => "COUNT($cond2)"
 328                         ],
 329                         [ 'cl_to' => $this->mName, 'page_id = cl_from' ],
 330                         __METHOD__,
 331                         [ 'LOCK IN SHARE MODE' ]
 332                 );
 333
 334                 if ( $this->mID ) {
 335                         # The category row already exists, so do a plain UPDATE instead
 336                         # of INSERT...ON DUPLICATE KEY UPDATE to avoid creating a gap
 337                         # in the cat_id sequence. The row may or may not be "affected".
 338                         $dbw->update(
 339                                 'category',
 340                                 [
 341                                         'cat_pages' => $result->pages,
 342                                         'cat_subcats' => $result->subcats,
 343                                         'cat_files' => $result->files
 344                                 ],
 345                                 [ 'cat_title' => $this->mName ],
 346                                 __METHOD__
 347                         );
 348                 } else {
 349                         $dbw->upsert(
 350                                 'category',
 351                                 [
 352                                         'cat_title' => $this->mName,
 353                                         'cat_pages' => $result->pages,
 354                                         'cat_subcats' => $result->subcats,
 355                                         'cat_files' => $result->files
 356                                 ],
 357                                 [ 'cat_title' ],
 358                                 [
 359                                         'cat_pages' => $result->pages,
 360                                         'cat_subcats' => $result->subcats,
 361                                         'cat_files' => $result->files
 362                                 ],
 363                                 __METHOD__
 364                         );
 365                 }
 366
 367                 $dbw->endAtomic( __METHOD__ );
 368
 369                 # Now we should update our local counts.
 370                 $this->mPages = $result->pages;
 371                 $this->mSubcats = $result->subcats;
 372                 $this->mFiles = $result->files;
 373
 374                 return true;
 375         }
 376 }