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