includes/Category.php

   1 <?php
   2 /**
   3  * Category objects are immutable, strictly speaking. If you call methods that change the database,
   4  * like to refresh link counts, the objects will be appropriately reinitialized.
   5  * Member variables are lazy-initialized.
   6  *
   7  * TODO: Move some stuff from CategoryPage.php to here, and use that.
   8  *
   9  * @author Simetrical
  10  */
  11
  12 class Category {
  13         /** Name of the category, normalized to DB-key form */
  14         private $mName = null;
  15         private $mID = null;
  16         /** Category page title */
  17         private $mTitle = null;
  18         /** Counts of membership (cat_pages, cat_subcats, cat_files) */
  19         private $mPages = null, $mSubcats = null, $mFiles = null;
  20
  21         private function __construct() { }
  22
  23         /**
  24          * Set up all member variables using a database query.
  25          * @return bool True on success, false on failure.
  26          */
  27         protected function initialize() {
  28                 if ( $this->mName === null && $this->mTitle )
  29                         $this->mName = $title->getDBkey();
  30
  31                 if ( $this->mName === null && $this->mID === null ) {
  32                         throw new MWException( __METHOD__ . ' has both names and IDs null' );
  33                 } elseif ( $this->mID === null ) {
  34                         $where = array( 'cat_title' => $this->mName );
  35                 } elseif ( $this->mName === null ) {
  36                         $where = array( 'cat_id' => $this->mID );
  37                 } else {
  38                         # Already initialized
  39                         return true;
  40                 }
  41                 $dbr = wfGetDB( DB_SLAVE );
  42                 $row = $dbr->selectRow(
  43                         'category',
  44                         array( 'cat_id', 'cat_title', 'cat_pages', 'cat_subcats', 'cat_files' ),
  45                         $where,
  46                         __METHOD__
  47                 );
  48
  49                 if ( !$row ) {
  50                         # Okay, there were no contents.  Nothing to initialize.
  51                         if ( $this->mTitle ) {
  52                                 # If there is a title object but no record in the category table, treat this as an empty category
  53                                 $this->mID      = false;
  54                                 $this->mName    = $this->mTitle->getDBkey();
  55                                 $this->mPages   = 0;
  56                                 $this->mSubcats = 0;
  57                                 $this->mFiles   = 0;
  58
  59                                 return true;
  60                         } else {
  61                                 return false; # Fail
  62                         }
  63                 }
  64
  65                 $this->mID      = $row->cat_id;
  66                 $this->mName    = $row->cat_title;
  67                 $this->mPages   = $row->cat_pages;
  68                 $this->mSubcats = $row->cat_subcats;
  69                 $this->mFiles   = $row->cat_files;
  70
  71                 # (bug 13683) If the count is negative, then 1) it's obviously wrong
  72                 # and should not be kept, and 2) we *probably* don't have to scan many
  73                 # rows to obtain the correct figure, so let's risk a one-time recount.
  74                 if ( $this->mPages < 0 || $this->mSubcats < 0 || $this->mFiles < 0 ) {
  75                         $this->refreshCounts();
  76                 }
  77
  78                 return true;
  79         }
  80
  81         /**
  82          * Factory function.
  83          *
  84          * @param $name Array: A category name (no "Category:" prefix).  It need
  85          *   not be normalized, with spaces replaced by underscores.
  86          * @return mixed Category, or false on a totally invalid name
  87          */
  88         public static function newFromName( $name ) {
  89                 $cat = new self();
  90                 $title = Title::makeTitleSafe( NS_CATEGORY, $name );
  91
  92                 if ( !is_object( $title ) ) {
  93                         return false;
  94                 }
  95
  96                 $cat->mTitle = $title;
  97                 $cat->mName = $title->getDBkey();
  98
  99                 return $cat;
 100         }
 101
 102         /**
 103          * Factory function.
 104          *
 105          * @param $title Title for the category page
 106          * @return Mixed: category, or false on a totally invalid name
 107          */
 108         public static function newFromTitle( $title ) {
 109                 $cat = new self();
 110
 111                 $cat->mTitle = $title;
 112                 $cat->mName = $title->getDBkey();
 113
 114                 return $cat;
 115         }
 116
 117         /**
 118          * Factory function.
 119          *
 120          * @param $id Integer: a category id
 121          * @return Category
 122          */
 123         public static function newFromID( $id ) {
 124                 $cat = new self();
 125                 $cat->mID = intval( $id );
 126                 return $cat;
 127         }
 128
 129         /**
 130          * Factory function, for constructing a Category object from a result set
 131          *
 132          * @param $row result set row, must contain the cat_xxx fields. If the fields are null,
 133          *        the resulting Category object will represent an empty category if a title object
 134          *        was given. If the fields are null and no title was given, this method fails and returns false.
 135          * @param $title optional title object for the category represented by the given row.
 136          *        May be provided if it is already known, to avoid having to re-create a title object later.
 137          * @return Category
 138          */
 139         public static function newFromRow( $row, $title = null ) {
 140                 $cat = new self();
 141                 $cat->mTitle = $title;
 142
 143                 # NOTE: the row often results from a LEFT JOIN on categorylinks. This may result in
 144                 #       all the cat_xxx fields being null, if the category page exists, but nothing
 145                 #       was ever added to the category. This case should be treated linke an empty
 146                 #       category, if possible.
 147
 148                 if ( $row->cat_title === null ) {
 149                         if ( $title === null ) {
 150                                 # the name is probably somewhere in the row, for example as page_title,
 151                                 # but we can't know that here...
 152                                 return false;
 153                         } else {
 154                                 $cat->mName = $title->getDBkey(); # if we have a title object, fetch the category name from there
 155                         }
 156
 157                         $cat->mID =   false;
 158                         $cat->mSubcats = 0;
 159                         $cat->mPages   = 0;
 160                         $cat->mFiles   = 0;
 161                 } else {
 162                         $cat->mName    = $row->cat_title;
 163                         $cat->mID      = $row->cat_id;
 164                         $cat->mSubcats = $row->cat_subcats;
 165                         $cat->mPages   = $row->cat_pages;
 166                         $cat->mFiles   = $row->cat_files;
 167                 }
 168
 169                 return $cat;
 170         }
 171
 172         /** @return mixed DB key name, or false on failure */
 173         public function getName() { return $this->getX( 'mName' ); }
 174
 175         /** @return mixed Category ID, or false on failure */
 176         public function getID() { return $this->getX( 'mID' ); }
 177
 178         /** @return mixed Total number of member pages, or false on failure */
 179         public function getPageCount() { return $this->getX( 'mPages' ); }
 180
 181         /** @return mixed Number of subcategories, or false on failure */
 182         public function getSubcatCount() { return $this->getX( 'mSubcats' ); }
 183
 184         /** @return mixed Number of member files, or false on failure */
 185         public function getFileCount() { return $this->getX( 'mFiles' ); }
 186
 187         /**
 188          * @return mixed The Title for this category, or false on failure.
 189          */
 190         public function getTitle() {
 191                 if ( $this->mTitle ) return $this->mTitle;
 192
 193                 if ( !$this->initialize() ) {
 194                         return false;
 195                 }
 196
 197                 $this->mTitle = Title::makeTitleSafe( NS_CATEGORY, $this->mName );
 198                 return $this->mTitle;
 199         }
 200
 201         /**
 202          * Fetch a TitleArray of up to $limit category members, beginning after the
 203          * category sort key $offset.
 204          * @param $limit integer
 205          * @param $offset string
 206          * @return TitleArray object for category members.
 207          */
 208         public function getMembers( $limit = false, $offset = '' ) {
 209                 $dbr = wfGetDB( DB_SLAVE );
 210
 211                 $conds = array( 'cl_to' => $this->getName(), 'cl_from = page_id' );
 212                 $options = array( 'ORDER BY' => 'cl_sortkey' );
 213
 214                 if ( $limit ) {
 215                         $options[ 'LIMIT' ] = $limit;
 216                 }
 217
 218                 if ( $offset !== '' ) {
 219                         $conds[] = 'cl_sortkey > ' . $dbr->addQuotes( $offset );
 220                 }
 221
 222                 return TitleArray::newFromResult(
 223                         $dbr->select(
 224                                 array( 'page', 'categorylinks' ),
 225                                 array( 'page_id', 'page_namespace', 'page_title', 'page_len',
 226                                         'page_is_redirect', 'page_latest' ),
 227                                 $conds,
 228                                 __METHOD__,
 229                                 $options
 230                         )
 231                 );
 232         }
 233
 234         /** Generic accessor */
 235         private function getX( $key ) {
 236                 if ( !$this->initialize() ) {
 237                         return false;
 238                 }
 239                 return $this-> { $key } ;
 240         }
 241
 242         /**
 243          * Refresh the counts for this category.
 244          *
 245          * @return bool True on success, false on failure
 246          */
 247         public function refreshCounts() {
 248                 if ( wfReadOnly() ) {
 249                         return false;
 250                 }
 251                 $dbw = wfGetDB( DB_MASTER );
 252                 $dbw->begin();
 253                 # Note, we must use names for this, since categorylinks does.
 254                 if ( $this->mName === null ) {
 255                         if ( !$this->initialize() ) {
 256                                 return false;
 257                         }
 258                 } else {
 259                         # Let's be sure that the row exists in the table.  We don't need to
 260                         # do this if we got the row from the table in initialization!
 261                         $seqVal = $dbw->nextSequenceValue( 'category_cat_id_seq' );
 262                         $dbw->insert(
 263                                 'category',
 264                                 array(
 265                                         'cat_id' => $seqVal,
 266                                         'cat_title' => $this->mName
 267                                 ),
 268                                 __METHOD__,
 269                                 'IGNORE'
 270                         );
 271                 }
 272
 273                 $cond1 = $dbw->conditional( 'page_namespace=' . NS_CATEGORY, 1, 'NULL' );
 274                 $cond2 = $dbw->conditional( 'page_namespace=' . NS_FILE, 1, 'NULL' );
 275                 $result = $dbw->selectRow(
 276                         array( 'categorylinks', 'page' ),
 277                         array( 'COUNT(*) AS pages',
 278                                    "COUNT($cond1) AS subcats",
 279                                    "COUNT($cond2) AS files"
 280                         ),
 281                         array( 'cl_to' => $this->mName, 'page_id = cl_from' ),
 282                         __METHOD__,
 283                         'LOCK IN SHARE MODE'
 284                 );
 285                 $ret = $dbw->update(
 286                         'category',
 287                         array(
 288                                 'cat_pages' => $result->pages,
 289                                 'cat_subcats' => $result->subcats,
 290                                 'cat_files' => $result->files
 291                         ),
 292                         array( 'cat_title' => $this->mName ),
 293                         __METHOD__
 294                 );
 295                 $dbw->commit();
 296
 297                 # Now we should update our local counts.
 298                 $this->mPages   = $result->pages;
 299                 $this->mSubcats = $result->subcats;
 300                 $this->mFiles   = $result->files;
 301
 302                 return $ret;
 303         }
 304 }