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
  64                 $dbr = wfGetDB( DB_SLAVE );
  65                 $row = $dbr->selectRow(
  66                         'category',
  67                         array( 'cat_id', 'cat_title', 'cat_pages', 'cat_subcats', 'cat_files' ),
  68                         $where,
  69                         __METHOD__
  70                 );
  71
  72
  73                 if ( !$row ) {
  74                         # Okay, there were no contents.  Nothing to initialize.
  75                         if ( $this->mTitle ) {
  76                                 # If there is a title object but no record in the category table,
  77                                 # treat this as an empty category.
  78                                 $this->mID = false;
  79                                 $this->mName = $this->mTitle->getDBkey();
  80                                 $this->mPages = 0;
  81                                 $this->mSubcats = 0;
  82                                 $this->mFiles = 0;
  83
  84                                 return true;
  85                         } else {
  86                                 return false; # Fail
  87                         }
  88                 }
  89
  90                 $this->mID = $row->cat_id;
  91                 $this->mName = $row->cat_title;
  92                 $this->mPages = $row->cat_pages;
  93                 $this->mSubcats = $row->cat_subcats;
  94                 $this->mFiles = $row->cat_files;
  95
  96                 # (bug 13683) If the count is negative, then 1) it's obviously wrong
  97                 # and should not be kept, and 2) we *probably* don't have to scan many
  98                 # rows to obtain the correct figure, so let's risk a one-time recount.
  99                 if ( $this->mPages < 0 || $this->mSubcats < 0 || $this->mFiles < 0 ) {
 100                         $this->refreshCounts();
 101                 }
 102
 103                 return true;
 104         }
 105
 106         /**
 107          * Factory function.
 108          *
 109          * @param array $name A category name (no "Category:" prefix).  It need
 110          *   not be normalized, with spaces replaced by underscores.
 111          * @return mixed Category, or false on a totally invalid name
 112          */
 113         public static function newFromName( $name ) {
 114                 $cat = new self();
 115                 $title = Title::makeTitleSafe( NS_CATEGORY, $name );
 116
 117                 if ( !is_object( $title ) ) {
 118                         return false;
 119                 }
 120
 121                 $cat->mTitle = $title;
 122                 $cat->mName = $title->getDBkey();
 123
 124                 return $cat;
 125         }
 126
 127         /**
 128          * Factory function.
 129          *
 130          * @param Title $title Title for the category page
 131          * @return Category|bool On a totally invalid name
 132          */
 133         public static function newFromTitle( $title ) {
 134                 $cat = new self();
 135
 136                 $cat->mTitle = $title;
 137                 $cat->mName = $title->getDBkey();
 138
 139                 return $cat;
 140         }
 141
 142         /**
 143          * Factory function.
 144          *
 145          * @param int $id A category id
 146          * @return Category
 147          */
 148         public static function newFromID( $id ) {
 149                 $cat = new self();
 150                 $cat->mID = intval( $id );
 151                 return $cat;
 152         }
 153
 154         /**
 155          * Factory function, for constructing a Category object from a result set
 156          *
 157          * @param object $row Result set row, must contain the cat_xxx fields. If the
 158          *   fields are null, the resulting Category object will represent an empty
 159          *   category if a title object was given. If the fields are null and no
 160          *   title was given, this method fails and returns false.
 161          * @param Title $title Optional title object for the category represented by
 162          *   the given row. May be provided if it is already known, to avoid having
 163          *   to re-create a title object later.
 164          * @return Category
 165          */
 166         public static function newFromRow( $row, $title = null ) {
 167                 $cat = new self();
 168                 $cat->mTitle = $title;
 169
 170                 # NOTE: the row often results from a LEFT JOIN on categorylinks. This may result in
 171                 #       all the cat_xxx fields being null, if the category page exists, but nothing
 172                 #       was ever added to the category. This case should be treated link an empty
 173                 #       category, if possible.
 174
 175                 if ( $row->cat_title === null ) {
 176                         if ( $title === null ) {
 177                                 # the name is probably somewhere in the row, for example as page_title,
 178                                 # but we can't know that here...
 179                                 return false;
 180                         } else {
 181                                 # if we have a title object, fetch the category name from there
 182                                 $cat->mName = $title->getDBkey();
 183                         }
 184
 185                         $cat->mID = false;
 186                         $cat->mSubcats = 0;
 187                         $cat->mPages = 0;
 188                         $cat->mFiles = 0;
 189                 } else {
 190                         $cat->mName = $row->cat_title;
 191                         $cat->mID = $row->cat_id;
 192                         $cat->mSubcats = $row->cat_subcats;
 193                         $cat->mPages = $row->cat_pages;
 194                         $cat->mFiles = $row->cat_files;
 195                 }
 196
 197                 return $cat;
 198         }
 199
 200         /**
 201          * @return mixed DB key name, or false on failure
 202          */
 203         public function getName() {
 204                 return $this->getX( 'mName' );
 205         }
 206
 207         /**
 208          * @return mixed Category ID, or false on failure
 209          */
 210         public function getID() {
 211                 return $this->getX( 'mID' );
 212         }
 213
 214         /**
 215          * @return mixed Total number of member pages, or false on failure
 216          */
 217         public function getPageCount() {
 218                 return $this->getX( 'mPages' );
 219         }
 220
 221         /**
 222          * @return mixed Number of subcategories, or false on failure
 223          */
 224         public function getSubcatCount() {
 225                 return $this->getX( 'mSubcats' );
 226         }
 227
 228         /**
 229          * @return mixed Number of member files, or false on failure
 230          */
 231         public function getFileCount() {
 232                 return $this->getX( 'mFiles' );
 233         }
 234
 235         /**
 236          * @return Title|bool Title for this category, or false on failure.
 237          */
 238         public function getTitle() {
 239                 if ( $this->mTitle ) {
 240                         return $this->mTitle;
 241                 }
 242
 243                 if ( !$this->initialize() ) {
 244                         return false;
 245                 }
 246
 247                 $this->mTitle = Title::makeTitleSafe( NS_CATEGORY, $this->mName );
 248                 return $this->mTitle;
 249         }
 250
 251         /**
 252          * Fetch a TitleArray of up to $limit category members, beginning after the
 253          * category sort key $offset.
 254          * @param int $limit
 255          * @param string $offset
 256          * @return TitleArray TitleArray object for category members.
 257          */
 258         public function getMembers( $limit = false, $offset = '' ) {
 259
 260                 $dbr = wfGetDB( DB_SLAVE );
 261
 262                 $conds = array( 'cl_to' => $this->getName(), 'cl_from = page_id' );
 263                 $options = array( 'ORDER BY' => 'cl_sortkey' );
 264
 265                 if ( $limit ) {
 266                         $options['LIMIT'] = $limit;
 267                 }
 268
 269                 if ( $offset !== '' ) {
 270                         $conds[] = 'cl_sortkey > ' . $dbr->addQuotes( $offset );
 271                 }
 272
 273                 $result = TitleArray::newFromResult(
 274                         $dbr->select(
 275                                 array( 'page', 'categorylinks' ),
 276                                 array( 'page_id', 'page_namespace', 'page_title', 'page_len',
 277                                         'page_is_redirect', 'page_latest' ),
 278                                 $conds,
 279                                 __METHOD__,
 280                                 $options
 281                         )
 282                 );
 283
 284
 285                 return $result;
 286         }
 287
 288         /**
 289          * Generic accessor
 290          * @param string $key
 291          * @return bool
 292          */
 293         private function getX( $key ) {
 294                 if ( !$this->initialize() ) {
 295                         return false;
 296                 }
 297                 return $this->{$key};
 298         }
 299
 300         /**
 301          * Refresh the counts for this category.
 302          *
 303          * @return bool True on success, false on failure
 304          */
 305         public function refreshCounts() {
 306                 if ( wfReadOnly() ) {
 307                         return false;
 308                 }
 309
 310                 # Note, we must use names for this, since categorylinks does.
 311                 if ( $this->mName === null ) {
 312                         if ( !$this->initialize() ) {
 313                                 return false;
 314                         }
 315                 }
 316
 317
 318                 $dbw = wfGetDB( DB_MASTER );
 319                 $dbw->startAtomic( __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->endAtomic( __METHOD__ );
 360
 361
 362                 # Now we should update our local counts.
 363                 $this->mPages = $result->pages;
 364                 $this->mSubcats = $result->subcats;
 365                 $this->mFiles = $result->files;
 366
 367                 return $ret;
 368         }
 369 }