includes/Category.php

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