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          * Set up all member variables using a database query.
  47          * @return bool True on success, false on failure.
  48          */
  49         protected function initialize() {
  50                 if ( $this->mName === null && $this->mID === null ) {
  51                         throw new MWException( __METHOD__ . ' has both names and IDs null' );
  52                 } elseif ( $this->mID === null ) {
  53                         $where = array( 'cat_title' => $this->mName );
  54                 } elseif ( $this->mName === null ) {
  55                         $where = array( 'cat_id' => $this->mID );
  56                 } else {
  57                         # Already initialized
  58                         return true;
  59                 }
  60                 $dbr = wfGetDB( DB_SLAVE );
  61                 $row = $dbr->selectRow(
  62                         'category',
  63                         array( 'cat_id', 'cat_title', 'cat_pages', 'cat_subcats', 'cat_files' ),
  64                         $where,
  65                         __METHOD__
  66                 );
  67
  68                 if ( !$row ) {
  69                         # Okay, there were no contents.  Nothing to initialize.
  70                         if ( $this->mTitle ) {
  71                                 # If there is a title object but no record in the category table, treat this as an empty category
  72                                 $this->mID      = false;
  73                                 $this->mName    = $this->mTitle->getDBkey();
  74                                 $this->mPages   = 0;
  75                                 $this->mSubcats = 0;
  76                                 $this->mFiles   = 0;
  77
  78                                 return true;
  79                         } else {
  80                                 return false; # Fail
  81                         }
  82                 }
  83
  84                 $this->mID      = $row->cat_id;
  85                 $this->mName    = $row->cat_title;
  86                 $this->mPages   = $row->cat_pages;
  87                 $this->mSubcats = $row->cat_subcats;
  88                 $this->mFiles   = $row->cat_files;
  89
  90                 # (bug 13683) If the count is negative, then 1) it's obviously wrong
  91                 # and should not be kept, and 2) we *probably* don't have to scan many
  92                 # rows to obtain the correct figure, so let's risk a one-time recount.
  93                 if ( $this->mPages < 0 || $this->mSubcats < 0 || $this->mFiles < 0 ) {
  94                         $this->refreshCounts();
  95                 }
  96
  97                 return true;
  98         }
  99
 100         /**
 101          * Factory function.
 102          *
 103          * @param $name Array: A category name (no "Category:" prefix).  It need
 104          *   not be normalized, with spaces replaced by underscores.
 105          * @return mixed Category, or false on a totally invalid name
 106          */
 107         public static function newFromName( $name ) {
 108                 $cat = new self();
 109                 $title = Title::makeTitleSafe( NS_CATEGORY, $name );
 110
 111                 if ( !is_object( $title ) ) {
 112                         return false;
 113                 }
 114
 115                 $cat->mTitle = $title;
 116                 $cat->mName = $title->getDBkey();
 117
 118                 return $cat;
 119         }
 120
 121         /**
 122          * Factory function.
 123          *
 124          * @param $title Title for the category page
 125          * @return Category|bool on a totally invalid name
 126          */
 127         public static function newFromTitle( $title ) {
 128                 $cat = new self();
 129
 130                 $cat->mTitle = $title;
 131                 $cat->mName = $title->getDBkey();
 132
 133                 return $cat;
 134         }
 135
 136         /**
 137          * Factory function.
 138          *
 139          * @param $id Integer: a category id
 140          * @return Category
 141          */
 142         public static function newFromID( $id ) {
 143                 $cat = new self();
 144                 $cat->mID = intval( $id );
 145                 return $cat;
 146         }
 147
 148         /**
 149          * Factory function, for constructing a Category object from a result set
 150          *
 151          * @param $row result set row, must contain the cat_xxx fields. If the fields are null,
 152          *        the resulting Category object will represent an empty category if a title object
 153          *        was given. If the fields are null and no title was given, this method fails and returns false.
 154          * @param Title $title optional title object for the category represented by the given row.
 155          *        May be provided if it is already known, to avoid having to re-create a title object later.
 156          * @return Category
 157          */
 158         public static function newFromRow( $row, $title = null ) {
 159                 $cat = new self();
 160                 $cat->mTitle = $title;
 161
 162                 # NOTE: the row often results from a LEFT JOIN on categorylinks. This may result in
 163                 #       all the cat_xxx fields being null, if the category page exists, but nothing
 164                 #       was ever added to the category. This case should be treated linke an empty
 165                 #       category, if possible.
 166
 167                 if ( $row->cat_title === null ) {
 168                         if ( $title === null ) {
 169                                 # the name is probably somewhere in the row, for example as page_title,
 170                                 # but we can't know that here...
 171                                 return false;
 172                         } else {
 173                                 $cat->mName = $title->getDBkey(); # if we have a title object, fetch the category name from there
 174                         }
 175
 176                         $cat->mID =   false;
 177                         $cat->mSubcats = 0;
 178                         $cat->mPages   = 0;
 179                         $cat->mFiles   = 0;
 180                 } else {
 181                         $cat->mName    = $row->cat_title;
 182                         $cat->mID      = $row->cat_id;
 183                         $cat->mSubcats = $row->cat_subcats;
 184                         $cat->mPages   = $row->cat_pages;
 185                         $cat->mFiles   = $row->cat_files;
 186                 }
 187
 188                 return $cat;
 189         }
 190
 191         /** @return mixed DB key name, or false on failure */
 192         public function getName() { return $this->getX( 'mName' ); }
 193
 194         /** @return mixed Category ID, or false on failure */
 195         public function getID() { return $this->getX( 'mID' ); }
 196
 197         /** @return mixed Total number of member pages, or false on failure */
 198         public function getPageCount() { return $this->getX( 'mPages' ); }
 199
 200         /** @return mixed Number of subcategories, or false on failure */
 201         public function getSubcatCount() { return $this->getX( 'mSubcats' ); }
 202
 203         /** @return mixed Number of member files, or false on failure */
 204         public function getFileCount() { return $this->getX( 'mFiles' ); }
 205
 206         /**
 207          * @return Title|bool Title for this category, or false on failure.
 208          */
 209         public function getTitle() {
 210                 if ( $this->mTitle ) return $this->mTitle;
 211
 212                 if ( !$this->initialize() ) {
 213                         return false;
 214                 }
 215
 216                 $this->mTitle = Title::makeTitleSafe( NS_CATEGORY, $this->mName );
 217                 return $this->mTitle;
 218         }
 219
 220         /**
 221          * Fetch a TitleArray of up to $limit category members, beginning after the
 222          * category sort key $offset.
 223          * @param $limit integer
 224          * @param $offset string
 225          * @return TitleArray object for category members.
 226          */
 227         public function getMembers( $limit = false, $offset = '' ) {
 228                 $dbr = wfGetDB( DB_SLAVE );
 229
 230                 $conds = array( 'cl_to' => $this->getName(), 'cl_from = page_id' );
 231                 $options = array( 'ORDER BY' => 'cl_sortkey' );
 232
 233                 if ( $limit ) {
 234                         $options[ 'LIMIT' ] = $limit;
 235                 }
 236
 237                 if ( $offset !== '' ) {
 238                         $conds[] = 'cl_sortkey > ' . $dbr->addQuotes( $offset );
 239                 }
 240
 241                 return TitleArray::newFromResult(
 242                         $dbr->select(
 243                                 array( 'page', 'categorylinks' ),
 244                                 array( 'page_id', 'page_namespace', 'page_title', 'page_len',
 245                                         'page_is_redirect', 'page_latest' ),
 246                                 $conds,
 247                                 __METHOD__,
 248                                 $options
 249                         )
 250                 );
 251         }
 252
 253         /**
 254          * Generic accessor
 255          * @return bool
 256          */
 257         private function getX( $key ) {
 258                 if ( !$this->initialize() ) {
 259                         return false;
 260                 }
 261                 return $this-> { $key } ;
 262         }
 263
 264         /**
 265          * Refresh the counts for this category.
 266          *
 267          * @return bool True on success, false on failure
 268          */
 269         public function refreshCounts() {
 270                 if ( wfReadOnly() ) {
 271                         return false;
 272                 }
 273
 274                 # Note, we must use names for this, since categorylinks does.
 275                 if ( $this->mName === null ) {
 276                         if ( !$this->initialize() ) {
 277                                 return false;
 278                         }
 279                 }
 280
 281                 $dbw = wfGetDB( DB_MASTER );
 282                 $dbw->begin( __METHOD__  );
 283
 284                 # Insert the row if it doesn't exist yet (e.g., this is being run via
 285                 # update.php from a pre-1.16 schema).  TODO: This will cause lots and
 286                 # lots of gaps on some non-MySQL DBMSes if you run populateCategory.php
 287                 # repeatedly.  Plus it's an extra query that's unneeded almost all the
 288                 # time.  This should be rewritten somehow, probably.
 289                 $seqVal = $dbw->nextSequenceValue( 'category_cat_id_seq' );
 290                 $dbw->insert(
 291                         'category',
 292                         array(
 293                                 'cat_id' => $seqVal,
 294                                 'cat_title' => $this->mName
 295                         ),
 296                         __METHOD__,
 297                         'IGNORE'
 298                 );
 299
 300                 $cond1 = $dbw->conditional( array( 'page_namespace' => NS_CATEGORY ), 1, 'NULL' );
 301                 $cond2 = $dbw->conditional( array( 'page_namespace' => NS_FILE ), 1, 'NULL' );
 302                 $result = $dbw->selectRow(
 303                         array( 'categorylinks', 'page' ),
 304                         array( 'pages' => 'COUNT(*)',
 305                                    'subcats' => "COUNT($cond1)",
 306                                    'files' => "COUNT($cond2)"
 307                         ),
 308                         array( 'cl_to' => $this->mName, 'page_id = cl_from' ),
 309                         __METHOD__,
 310                         'LOCK IN SHARE MODE'
 311                 );
 312                 $ret = $dbw->update(
 313                         'category',
 314                         array(
 315                                 'cat_pages' => $result->pages,
 316                                 'cat_subcats' => $result->subcats,
 317                                 'cat_files' => $result->files
 318                         ),
 319                         array( 'cat_title' => $this->mName ),
 320                         __METHOD__
 321                 );
 322                 $dbw->commit( __METHOD__ );
 323
 324                 # Now we should update our local counts.
 325                 $this->mPages   = $result->pages;
 326                 $this->mSubcats = $result->subcats;
 327                 $this->mFiles   = $result->files;
 328
 329                 return $ret;
 330         }
 331 }