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 = array( 'cat_title' => $this->mName );
  56                 } elseif ( $this->mName === null ) {
  57                         $where = array( 'cat_id' => $this->mID );
  58                 } else {
  59                         # Already initialized
  60                         return true;
  61                 }
  62
  63                 wfProfileIn( __METHOD__ );
  64
  65                 $dbr = wfGetDB( DB_SLAVE );
  66                 $row = $dbr->selectRow(
  67                         'category',
  68                         array( 'cat_id', 'cat_title', 'cat_pages', 'cat_subcats', 'cat_files' ),
  69                         $where,
  70                         __METHOD__
  71                 );
  72
  73                 wfProfileOut( __METHOD__ );
  74
  75                 if ( !$row ) {
  76                         # Okay, there were no contents.  Nothing to initialize.
  77                         if ( $this->mTitle ) {
  78                                 # If there is a title object but no record in the category table, treat this as an empty category
  79                                 $this->mID = false;
  80                                 $this->mName = $this->mTitle->getDBkey();
  81                                 $this->mPages = 0;
  82                                 $this->mSubcats = 0;
  83                                 $this->mFiles = 0;
  84
  85                                 return true;
  86                         } else {
  87                                 return false; # Fail
  88                         }
  89                 }
  90
  91                 $this->mID = $row->cat_id;
  92                 $this->mName = $row->cat_title;
  93                 $this->mPages = $row->cat_pages;
  94                 $this->mSubcats = $row->cat_subcats;
  95                 $this->mFiles = $row->cat_files;
  96
  97                 # (bug 13683) If the count is negative, then 1) it's obviously wrong
  98                 # and should not be kept, and 2) we *probably* don't have to scan many
  99                 # rows to obtain the correct figure, so let's risk a one-time recount.
 100                 if ( $this->mPages < 0 || $this->mSubcats < 0 || $this->mFiles < 0 ) {
 101                         $this->refreshCounts();
 102                 }
 103
 104                 return true;
 105         }
 106
 107         /**
 108          * Factory function.
 109          *
 110          * @param array $name A category name (no "Category:" prefix).  It need
 111          *   not be normalized, with spaces replaced by underscores.
 112          * @return mixed Category, or false on a totally invalid name
 113          */
 114         public static function newFromName( $name ) {
 115                 $cat = new self();
 116                 $title = Title::makeTitleSafe( NS_CATEGORY, $name );
 117
 118                 if ( !is_object( $title ) ) {
 119                         return false;
 120                 }
 121
 122                 $cat->mTitle = $title;
 123                 $cat->mName = $title->getDBkey();
 124
 125                 return $cat;
 126         }
 127
 128         /**
 129          * Factory function.
 130          *
 131          * @param $title Title for the category page
 132          * @return Category|bool on a totally invalid name
 133          */
 134         public static function newFromTitle( $title ) {
 135                 $cat = new self();
 136
 137                 $cat->mTitle = $title;
 138                 $cat->mName = $title->getDBkey();
 139
 140                 return $cat;
 141         }
 142
 143         /**
 144          * Factory function.
 145          *
 146          * @param $id Integer: a category id
 147          * @return Category
 148          */
 149         public static function newFromID( $id ) {
 150                 $cat = new self();
 151                 $cat->mID = intval( $id );
 152                 return $cat;
 153         }
 154
 155         /**
 156          * Factory function, for constructing a Category object from a result set
 157          *
 158          * @param $row result set row, must contain the cat_xxx fields. If the fields are null,
 159          *        the resulting Category object will represent an empty category if a title object
 160          *        was given. If the fields are null and no title was given, this method fails and returns false.
 161          * @param Title $title optional title object for the category represented by the given row.
 162          *        May be provided if it is already known, to avoid having to re-create a title object later.
 163          * @return Category
 164          */
 165         public static function newFromRow( $row, $title = null ) {
 166                 $cat = new self();
 167                 $cat->mTitle = $title;
 168
 169                 # NOTE: the row often results from a LEFT JOIN on categorylinks. This may result in
 170                 #       all the cat_xxx fields being null, if the category page exists, but nothing
 171                 #       was ever added to the category. This case should be treated link an empty
 172                 #       category, if possible.
 173
 174                 if ( $row->cat_title === null ) {
 175                         if ( $title === null ) {
 176                                 # the name is probably somewhere in the row, for example as page_title,
 177                                 # but we can't know that here...
 178                                 return false;
 179                         } else {
 180                                 $cat->mName = $title->getDBkey(); # if we have a title object, fetch the category name from there
 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 $limit integer
 253          * @param $offset string
 254          * @return TitleArray object for category members.
 255          */
 256         public function getMembers( $limit = false, $offset = '' ) {
 257                 wfProfileIn( __METHOD__ );
 258
 259                 $dbr = wfGetDB( DB_SLAVE );
 260
 261                 $conds = array( 'cl_to' => $this->getName(), 'cl_from = page_id' );
 262                 $options = array( 'ORDER BY' => 'cl_sortkey' );
 263
 264                 if ( $limit ) {
 265                         $options['LIMIT'] = $limit;
 266                 }
 267
 268                 if ( $offset !== '' ) {
 269                         $conds[] = 'cl_sortkey > ' . $dbr->addQuotes( $offset );
 270                 }
 271
 272                 $result = TitleArray::newFromResult(
 273                         $dbr->select(
 274                                 array( 'page', 'categorylinks' ),
 275                                 array( 'page_id', 'page_namespace', 'page_title', 'page_len',
 276                                         'page_is_redirect', 'page_latest' ),
 277                                 $conds,
 278                                 __METHOD__,
 279                                 $options
 280                         )
 281                 );
 282
 283                 wfProfileOut( __METHOD__ );
 284
 285                 return $result;
 286         }
 287
 288         /**
 289          * Generic accessor
 290          * @return bool
 291          */
 292         private function getX( $key ) {
 293                 if ( !$this->initialize() ) {
 294                         return false;
 295                 }
 296                 return $this->{$key};
 297         }
 298
 299         /**
 300          * Refresh the counts for this category.
 301          *
 302          * @return bool True on success, false on failure
 303          */
 304         public function refreshCounts() {
 305                 if ( wfReadOnly() ) {
 306                         return false;
 307                 }
 308
 309                 # Note, we must use names for this, since categorylinks does.
 310                 if ( $this->mName === null ) {
 311                         if ( !$this->initialize() ) {
 312                                 return false;
 313                         }
 314                 }
 315
 316                 wfProfileIn( __METHOD__ );
 317
 318                 $dbw = wfGetDB( DB_MASTER );
 319                 $dbw->begin( __METHOD__ );
 320
 321                 # Insert the row if it doesn't exist yet (e.g., this is being run via
 322                 # update.php from a pre-1.16 schema).  TODO: This will cause lots and
 323                 # lots of gaps on some non-MySQL DBMSes if you run populateCategory.php
 324                 # repeatedly.  Plus it's an extra query that's unneeded almost all the
 325                 # time.  This should be rewritten somehow, probably.
 326                 $seqVal = $dbw->nextSequenceValue( 'category_cat_id_seq' );
 327                 $dbw->insert(
 328                         'category',
 329                         array(
 330                                 'cat_id' => $seqVal,
 331                                 'cat_title' => $this->mName
 332                         ),
 333                         __METHOD__,
 334                         'IGNORE'
 335                 );
 336
 337                 $cond1 = $dbw->conditional( array( 'page_namespace' => NS_CATEGORY ), 1, 'NULL' );
 338                 $cond2 = $dbw->conditional( array( 'page_namespace' => NS_FILE ), 1, 'NULL' );
 339                 $result = $dbw->selectRow(
 340                         array( 'categorylinks', 'page' ),
 341                         array( 'pages' => 'COUNT(*)',
 342                                 'subcats' => "COUNT($cond1)",
 343                                 'files' => "COUNT($cond2)"
 344                         ),
 345                         array( 'cl_to' => $this->mName, 'page_id = cl_from' ),
 346                         __METHOD__,
 347                         array( 'LOCK IN SHARE MODE' )
 348                 );
 349                 $ret = $dbw->update(
 350                         'category',
 351                         array(
 352                                 'cat_pages' => $result->pages,
 353                                 'cat_subcats' => $result->subcats,
 354                                 'cat_files' => $result->files
 355                         ),
 356                         array( 'cat_title' => $this->mName ),
 357                         __METHOD__
 358                 );
 359                 $dbw->commit( __METHOD__ );
 360
 361                 wfProfileOut( __METHOD__ );
 362
 363                 # Now we should update our local counts.
 364                 $this->mPages = $result->pages;
 365                 $this->mSubcats = $result->subcats;
 366                 $this->mFiles = $result->files;
 367
 368                 return $ret;
 369         }
 370 }