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          * @throws MWException
  48          * @return bool True on success, false on failure.
  49          */
  50         protected function initialize() {
  51                 if ( $this->mName === null && $this->mID === null ) {
  52                         throw new MWException( __METHOD__ . ' has both names and IDs null' );
  53                 } elseif ( $this->mID === null ) {
  54                         $where = array( 'cat_title' => $this->mName );
  55                 } elseif ( $this->mName === null ) {
  56                         $where = array( 'cat_id' => $this->mID );
  57                 } else {
  58                         # Already initialized
  59                         return true;
  60                 }
  61                 $dbr = wfGetDB( DB_SLAVE );
  62                 $row = $dbr->selectRow(
  63                         'category',
  64                         array( 'cat_id', 'cat_title', 'cat_pages', 'cat_subcats', 'cat_files' ),
  65                         $where,
  66                         __METHOD__
  67                 );
  68
  69                 if ( !$row ) {
  70                         # Okay, there were no contents.  Nothing to initialize.
  71                         if ( $this->mTitle ) {
  72                                 # If there is a title object but no record in the category table, treat this as an empty category
  73                                 $this->mID      = false;
  74                                 $this->mName    = $this->mTitle->getDBkey();
  75                                 $this->mPages   = 0;
  76                                 $this->mSubcats = 0;
  77                                 $this->mFiles   = 0;
  78
  79                                 return true;
  80                         } else {
  81                                 return false; # Fail
  82                         }
  83                 }
  84
  85                 $this->mID      = $row->cat_id;
  86                 $this->mName    = $row->cat_title;
  87                 $this->mPages   = $row->cat_pages;
  88                 $this->mSubcats = $row->cat_subcats;
  89                 $this->mFiles   = $row->cat_files;
  90
  91                 # (bug 13683) If the count is negative, then 1) it's obviously wrong
  92                 # and should not be kept, and 2) we *probably* don't have to scan many
  93                 # rows to obtain the correct figure, so let's risk a one-time recount.
  94                 if ( $this->mPages < 0 || $this->mSubcats < 0 || $this->mFiles < 0 ) {
  95                         $this->refreshCounts();
  96                 }
  97
  98                 return true;
  99         }
 100
 101         /**
 102          * Factory function.
 103          *
 104          * @param $name Array: A category name (no "Category:" prefix).  It need
 105          *   not be normalized, with spaces replaced by underscores.
 106          * @return mixed Category, or false on a totally invalid name
 107          */
 108         public static function newFromName( $name ) {
 109                 $cat = new self();
 110                 $title = Title::makeTitleSafe( NS_CATEGORY, $name );
 111
 112                 if ( !is_object( $title ) ) {
 113                         return false;
 114                 }
 115
 116                 $cat->mTitle = $title;
 117                 $cat->mName = $title->getDBkey();
 118
 119                 return $cat;
 120         }
 121
 122         /**
 123          * Factory function.
 124          *
 125          * @param $title Title for the category page
 126          * @return Category|bool on a totally invalid name
 127          */
 128         public static function newFromTitle( $title ) {
 129                 $cat = new self();
 130
 131                 $cat->mTitle = $title;
 132                 $cat->mName = $title->getDBkey();
 133
 134                 return $cat;
 135         }
 136
 137         /**
 138          * Factory function.
 139          *
 140          * @param $id Integer: a category id
 141          * @return Category
 142          */
 143         public static function newFromID( $id ) {
 144                 $cat = new self();
 145                 $cat->mID = intval( $id );
 146                 return $cat;
 147         }
 148
 149         /**
 150          * Factory function, for constructing a Category object from a result set
 151          *
 152          * @param $row result set row, must contain the cat_xxx fields. If the fields are null,
 153          *        the resulting Category object will represent an empty category if a title object
 154          *        was given. If the fields are null and no title was given, this method fails and returns false.
 155          * @param Title $title optional title object for the category represented by the given row.
 156          *        May be provided if it is already known, to avoid having to re-create a title object later.
 157          * @return Category
 158          */
 159         public static function newFromRow( $row, $title = null ) {
 160                 $cat = new self();
 161                 $cat->mTitle = $title;
 162
 163                 # NOTE: the row often results from a LEFT JOIN on categorylinks. This may result in
 164                 #       all the cat_xxx fields being null, if the category page exists, but nothing
 165                 #       was ever added to the category. This case should be treated linke an empty
 166                 #       category, if possible.
 167
 168                 if ( $row->cat_title === null ) {
 169                         if ( $title === null ) {
 170                                 # the name is probably somewhere in the row, for example as page_title,
 171                                 # but we can't know that here...
 172                                 return false;
 173                         } else {
 174                                 $cat->mName = $title->getDBkey(); # if we have a title object, fetch the category name from there
 175                         }
 176
 177                         $cat->mID =   false;
 178                         $cat->mSubcats = 0;
 179                         $cat->mPages   = 0;
 180                         $cat->mFiles   = 0;
 181                 } else {
 182                         $cat->mName    = $row->cat_title;
 183                         $cat->mID      = $row->cat_id;
 184                         $cat->mSubcats = $row->cat_subcats;
 185                         $cat->mPages   = $row->cat_pages;
 186                         $cat->mFiles   = $row->cat_files;
 187                 }
 188
 189                 return $cat;
 190         }
 191
 192         /** @return mixed DB key name, or false on failure */
 193         public function getName() { return $this->getX( 'mName' ); }
 194
 195         /** @return mixed Category ID, or false on failure */
 196         public function getID() { return $this->getX( 'mID' ); }
 197
 198         /** @return mixed Total number of member pages, or false on failure */
 199         public function getPageCount() { return $this->getX( 'mPages' ); }
 200
 201         /** @return mixed Number of subcategories, or false on failure */
 202         public function getSubcatCount() { return $this->getX( 'mSubcats' ); }
 203
 204         /** @return mixed Number of member files, or false on failure */
 205         public function getFileCount() { return $this->getX( 'mFiles' ); }
 206
 207         /**
 208          * @return Title|bool Title for this category, or false on failure.
 209          */
 210         public function getTitle() {
 211                 if ( $this->mTitle ) return $this->mTitle;
 212
 213                 if ( !$this->initialize() ) {
 214                         return false;
 215                 }
 216
 217                 $this->mTitle = Title::makeTitleSafe( NS_CATEGORY, $this->mName );
 218                 return $this->mTitle;
 219         }
 220
 221         /**
 222          * Fetch a TitleArray of up to $limit category members, beginning after the
 223          * category sort key $offset.
 224          * @param $limit integer
 225          * @param $offset string
 226          * @return TitleArray object for category members.
 227          */
 228         public function getMembers( $limit = false, $offset = '' ) {
 229                 $dbr = wfGetDB( DB_SLAVE );
 230
 231                 $conds = array( 'cl_to' => $this->getName(), 'cl_from = page_id' );
 232                 $options = array( 'ORDER BY' => 'cl_sortkey' );
 233
 234                 if ( $limit ) {
 235                         $options[ 'LIMIT' ] = $limit;
 236                 }
 237
 238                 if ( $offset !== '' ) {
 239                         $conds[] = 'cl_sortkey > ' . $dbr->addQuotes( $offset );
 240                 }
 241
 242                 return TitleArray::newFromResult(
 243                         $dbr->select(
 244                                 array( 'page', 'categorylinks' ),
 245                                 array( 'page_id', 'page_namespace', 'page_title', 'page_len',
 246                                         'page_is_redirect', 'page_latest' ),
 247                                 $conds,
 248                                 __METHOD__,
 249                                 $options
 250                         )
 251                 );
 252         }
 253
 254         /**
 255          * Generic accessor
 256          * @return bool
 257          */
 258         private function getX( $key ) {
 259                 if ( !$this->initialize() ) {
 260                         return false;
 261                 }
 262                 return $this-> { $key } ;
 263         }
 264
 265         /**
 266          * Refresh the counts for this category.
 267          *
 268          * @return bool True on success, false on failure
 269          */
 270         public function refreshCounts() {
 271                 if ( wfReadOnly() ) {
 272                         return false;
 273                 }
 274
 275                 # Note, we must use names for this, since categorylinks does.
 276                 if ( $this->mName === null ) {
 277                         if ( !$this->initialize() ) {
 278                                 return false;
 279                         }
 280                 }
 281
 282                 $dbw = wfGetDB( DB_MASTER );
 283                 $dbw->begin( __METHOD__  );
 284
 285                 # Insert the row if it doesn't exist yet (e.g., this is being run via
 286                 # update.php from a pre-1.16 schema).  TODO: This will cause lots and
 287                 # lots of gaps on some non-MySQL DBMSes if you run populateCategory.php
 288                 # repeatedly.  Plus it's an extra query that's unneeded almost all the
 289                 # time.  This should be rewritten somehow, probably.
 290                 $seqVal = $dbw->nextSequenceValue( 'category_cat_id_seq' );
 291                 $dbw->insert(
 292                         'category',
 293                         array(
 294                                 'cat_id' => $seqVal,
 295                                 'cat_title' => $this->mName
 296                         ),
 297                         __METHOD__,
 298                         'IGNORE'
 299                 );
 300
 301                 $cond1 = $dbw->conditional( array( 'page_namespace' => NS_CATEGORY ), 1, 'NULL' );
 302                 $cond2 = $dbw->conditional( array( 'page_namespace' => NS_FILE ), 1, 'NULL' );
 303                 $result = $dbw->selectRow(
 304                         array( 'categorylinks', 'page' ),
 305                         array( 'pages' => 'COUNT(*)',
 306                                    'subcats' => "COUNT($cond1)",
 307                                    'files' => "COUNT($cond2)"
 308                         ),
 309                         array( 'cl_to' => $this->mName, 'page_id = cl_from' ),
 310                         __METHOD__,
 311                         'LOCK IN SHARE MODE'
 312                 );
 313                 $ret = $dbw->update(
 314                         'category',
 315                         array(
 316                                 'cat_pages' => $result->pages,
 317                                 'cat_subcats' => $result->subcats,
 318                                 'cat_files' => $result->files
 319                         ),
 320                         array( 'cat_title' => $this->mName ),
 321                         __METHOD__
 322                 );
 323                 $dbw->commit( __METHOD__ );
 324
 325                 # Now we should update our local counts.
 326                 $this->mPages   = $result->pages;
 327                 $this->mSubcats = $result->subcats;
 328                 $this->mFiles   = $result->files;
 329
 330                 return $ret;
 331         }
 332 }