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->refreshCounts();
  99                 }
 100
 101                 return true;
 102         }
 103
 104         /**
 105          * Factory function.
 106          *
 107          * @param array $name A category name (no "Category:" prefix).  It need
 108          *   not be normalized, with spaces replaced by underscores.
 109          * @return mixed Category, or false on a totally invalid name
 110          */
 111         public static function newFromName( $name ) {
 112                 $cat = new self();
 113                 $title = Title::makeTitleSafe( NS_CATEGORY, $name );
 114
 115                 if ( !is_object( $title ) ) {
 116                         return false;
 117                 }
 118
 119                 $cat->mTitle = $title;
 120                 $cat->mName = $title->getDBkey();
 121
 122                 return $cat;
 123         }
 124
 125         /**
 126          * Factory function.
 127          *
 128          * @param Title $title Title for the category page
 129          * @return Category|bool On a totally invalid name
 130          */
 131         public static function newFromTitle( $title ) {
 132                 $cat = new self();
 133
 134                 $cat->mTitle = $title;
 135                 $cat->mName = $title->getDBkey();
 136
 137                 return $cat;
 138         }
 139
 140         /**
 141          * Factory function.
 142          *
 143          * @param int $id A category id
 144          * @return Category
 145          */
 146         public static function newFromID( $id ) {
 147                 $cat = new self();
 148                 $cat->mID = intval( $id );
 149                 return $cat;
 150         }
 151
 152         /**
 153          * Factory function, for constructing a Category object from a result set
 154          *
 155          * @param object $row Result set row, must contain the cat_xxx fields. If the
 156          *   fields are null, the resulting Category object will represent an empty
 157          *   category if a title object was given. If the fields are null and no
 158          *   title was given, this method fails and returns false.
 159          * @param Title $title Optional title object for the category represented by
 160          *   the given row. May be provided if it is already known, to avoid having
 161          *   to re-create a title object later.
 162          * @return Category
 163          */
 164         public static function newFromRow( $row, $title = null ) {
 165                 $cat = new self();
 166                 $cat->mTitle = $title;
 167
 168                 # NOTE: the row often results from a LEFT JOIN on categorylinks. This may result in
 169                 #       all the cat_xxx fields being null, if the category page exists, but nothing
 170                 #       was ever added to the category. This case should be treated link an empty
 171                 #       category, if possible.
 172
 173                 if ( $row->cat_title === null ) {
 174                         if ( $title === null ) {
 175                                 # the name is probably somewhere in the row, for example as page_title,
 176                                 # but we can't know that here...
 177                                 return false;
 178                         } else {
 179                                 # if we have a title object, fetch the category name from there
 180                                 $cat->mName = $title->getDBkey();
 181                         }
 182
 183                         $cat->mID = false;
 184                         $cat->mSubcats = 0;
 185                         $cat->mPages = 0;
 186                         $cat->mFiles = 0;
 187                 } else {
 188                         $cat->mName = $row->cat_title;
 189                         $cat->mID = $row->cat_id;
 190                         $cat->mSubcats = $row->cat_subcats;
 191                         $cat->mPages = $row->cat_pages;
 192                         $cat->mFiles = $row->cat_files;
 193                 }
 194
 195                 return $cat;
 196         }
 197
 198         /**
 199          * @return mixed DB key name, or false on failure
 200          */
 201         public function getName() {
 202                 return $this->getX( 'mName' );
 203         }
 204
 205         /**
 206          * @return mixed Category ID, or false on failure
 207          */
 208         public function getID() {
 209                 return $this->getX( 'mID' );
 210         }
 211
 212         /**
 213          * @return mixed Total number of member pages, or false on failure
 214          */
 215         public function getPageCount() {
 216                 return $this->getX( 'mPages' );
 217         }
 218
 219         /**
 220          * @return mixed Number of subcategories, or false on failure
 221          */
 222         public function getSubcatCount() {
 223                 return $this->getX( 'mSubcats' );
 224         }
 225
 226         /**
 227          * @return mixed Number of member files, or false on failure
 228          */
 229         public function getFileCount() {
 230                 return $this->getX( 'mFiles' );
 231         }
 232
 233         /**
 234          * @return Title|bool Title for this category, or false on failure.
 235          */
 236         public function getTitle() {
 237                 if ( $this->mTitle ) {
 238                         return $this->mTitle;
 239                 }
 240
 241                 if ( !$this->initialize() ) {
 242                         return false;
 243                 }
 244
 245                 $this->mTitle = Title::makeTitleSafe( NS_CATEGORY, $this->mName );
 246                 return $this->mTitle;
 247         }
 248
 249         /**
 250          * Fetch a TitleArray of up to $limit category members, beginning after the
 251          * category sort key $offset.
 252          * @param int $limit
 253          * @param string $offset
 254          * @return TitleArray TitleArray object for category members.
 255          */
 256         public function getMembers( $limit = false, $offset = '' ) {
 257
 258                 $dbr = wfGetDB( DB_SLAVE );
 259
 260                 $conds = [ 'cl_to' => $this->getName(), 'cl_from = page_id' ];
 261                 $options = [ 'ORDER BY' => 'cl_sortkey' ];
 262
 263                 if ( $limit ) {
 264                         $options['LIMIT'] = $limit;
 265                 }
 266
 267                 if ( $offset !== '' ) {
 268                         $conds[] = 'cl_sortkey > ' . $dbr->addQuotes( $offset );
 269                 }
 270
 271                 $result = TitleArray::newFromResult(
 272                         $dbr->select(
 273                                 [ 'page', 'categorylinks' ],
 274                                 [ 'page_id', 'page_namespace', 'page_title', 'page_len',
 275                                         'page_is_redirect', 'page_latest' ],
 276                                 $conds,
 277                                 __METHOD__,
 278                                 $options
 279                         )
 280                 );
 281
 282                 return $result;
 283         }
 284
 285         /**
 286          * Generic accessor
 287          * @param string $key
 288          * @return bool
 289          */
 290         private function getX( $key ) {
 291                 if ( !$this->initialize() ) {
 292                         return false;
 293                 }
 294                 return $this->{$key};
 295         }
 296
 297         /**
 298          * Refresh the counts for this category.
 299          *
 300          * @return bool True on success, false on failure
 301          */
 302         public function refreshCounts() {
 303                 if ( wfReadOnly() ) {
 304                         return false;
 305                 }
 306
 307                 # If we have just a category name, find out whether there is an
 308                 # existing row. Or if we have just an ID, get the name, because
 309                 # that's what categorylinks uses.
 310                 if ( !$this->initialize() ) {
 311                         return false;
 312                 }
 313
 314                 $dbw = wfGetDB( DB_MASTER );
 315                 $dbw->startAtomic( __METHOD__ );
 316
 317                 $cond1 = $dbw->conditional( [ 'page_namespace' => NS_CATEGORY ], 1, 'NULL' );
 318                 $cond2 = $dbw->conditional( [ 'page_namespace' => NS_FILE ], 1, 'NULL' );
 319                 $result = $dbw->selectRow(
 320                         [ 'categorylinks', 'page' ],
 321                         [ 'pages' => 'COUNT(*)',
 322                                 'subcats' => "COUNT($cond1)",
 323                                 'files' => "COUNT($cond2)"
 324                         ],
 325                         [ 'cl_to' => $this->mName, 'page_id = cl_from' ],
 326                         __METHOD__,
 327                         [ 'LOCK IN SHARE MODE' ]
 328                 );
 329
 330                 if ( $this->mID ) {
 331                         # The category row already exists, so do a plain UPDATE instead
 332                         # of INSERT...ON DUPLICATE KEY UPDATE to avoid creating a gap
 333                         # in the cat_id sequence. The row may or may not be "affected".
 334                         $dbw->update(
 335                                 'category',
 336                                 [
 337                                         'cat_pages' => $result->pages,
 338                                         'cat_subcats' => $result->subcats,
 339                                         'cat_files' => $result->files
 340                                 ],
 341                                 [ 'cat_title' => $this->mName ],
 342                                 __METHOD__
 343                         );
 344                 } else {
 345                         $dbw->upsert(
 346                                 'category',
 347                                 [
 348                                         'cat_title' => $this->mName,
 349                                         'cat_pages' => $result->pages,
 350                                         'cat_subcats' => $result->subcats,
 351                                         'cat_files' => $result->files
 352                                 ],
 353                                 [ 'cat_title' ],
 354                                 [
 355                                         'cat_pages' => $result->pages,
 356                                         'cat_subcats' => $result->subcats,
 357                                         'cat_files' => $result->files
 358                                 ],
 359                                 __METHOD__
 360                         );
 361                 }
 362
 363                 $dbw->endAtomic( __METHOD__ );
 364
 365                 # Now we should update our local counts.
 366                 $this->mPages = $result->pages;
 367                 $this->mSubcats = $result->subcats;
 368                 $this->mFiles = $result->files;
 369
 370                 return true;
 371         }
 372 }