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 = $this->mTitle->getDBkey();
  30                 }
  31
  32                 if ( $this->mName === null && $this->mID === null ) {
  33                         throw new MWException( __METHOD__ . ' has both names and IDs null' );
  34                 } elseif ( $this->mID === null ) {
  35                         $where = array( 'cat_title' => $this->mName );
  36                 } elseif ( $this->mName === null ) {
  37                         $where = array( 'cat_id' => $this->mID );
  38                 } else {
  39                         # Already initialized
  40                         return true;
  41                 }
  42                 $dbr = wfGetDB( DB_SLAVE );
  43                 $row = $dbr->selectRow(
  44                         'category',
  45                         array( 'cat_id', 'cat_title', 'cat_pages', 'cat_subcats', 'cat_files' ),
  46                         $where,
  47                         __METHOD__
  48                 );
  49
  50                 if ( !$row ) {
  51                         # Okay, there were no contents.  Nothing to initialize.
  52                         if ( $this->mTitle ) {
  53                                 # If there is a title object but no record in the category table, treat this as an empty category
  54                                 $this->mID      = false;
  55                                 $this->mName    = $this->mTitle->getDBkey();
  56                                 $this->mPages   = 0;
  57                                 $this->mSubcats = 0;
  58                                 $this->mFiles   = 0;
  59
  60                                 return true;
  61                         } else {
  62                                 return false; # Fail
  63                         }
  64                 }
  65
  66                 $this->mID      = $row->cat_id;
  67                 $this->mName    = $row->cat_title;
  68                 $this->mPages   = $row->cat_pages;
  69                 $this->mSubcats = $row->cat_subcats;
  70                 $this->mFiles   = $row->cat_files;
  71
  72                 # (bug 13683) If the count is negative, then 1) it's obviously wrong
  73                 # and should not be kept, and 2) we *probably* don't have to scan many
  74                 # rows to obtain the correct figure, so let's risk a one-time recount.
  75                 if ( $this->mPages < 0 || $this->mSubcats < 0 || $this->mFiles < 0 ) {
  76                         $this->refreshCounts();
  77                 }
  78
  79                 return true;
  80         }
  81
  82         /**
  83          * Factory function.
  84          *
  85          * @param $name Array: A category name (no "Category:" prefix).  It need
  86          *   not be normalized, with spaces replaced by underscores.
  87          * @return mixed Category, or false on a totally invalid name
  88          */
  89         public static function newFromName( $name ) {
  90                 $cat = new self();
  91                 $title = Title::makeTitleSafe( NS_CATEGORY, $name );
  92
  93                 if ( !is_object( $title ) ) {
  94                         return false;
  95                 }
  96
  97                 $cat->mTitle = $title;
  98                 $cat->mName = $title->getDBkey();
  99
 100                 return $cat;
 101         }
 102
 103         /**
 104          * Factory function.
 105          *
 106          * @param $title Title for the category page
 107          * @return Mixed: category, or false on a totally invalid name
 108          */
 109         public static function newFromTitle( $title ) {
 110                 $cat = new self();
 111
 112                 $cat->mTitle = $title;
 113                 $cat->mName = $title->getDBkey();
 114
 115                 return $cat;
 116         }
 117
 118         /**
 119          * Factory function.
 120          *
 121          * @param $id Integer: a category id
 122          * @return Category
 123          */
 124         public static function newFromID( $id ) {
 125                 $cat = new self();
 126                 $cat->mID = intval( $id );
 127                 return $cat;
 128         }
 129
 130         /**
 131          * Factory function, for constructing a Category object from a result set
 132          *
 133          * @param $row result set row, must contain the cat_xxx fields. If the fields are null,
 134          *        the resulting Category object will represent an empty category if a title object
 135          *        was given. If the fields are null and no title was given, this method fails and returns false.
 136          * @param $title optional title object for the category represented by the given row.
 137          *        May be provided if it is already known, to avoid having to re-create a title object later.
 138          * @return Category
 139          */
 140         public static function newFromRow( $row, $title = null ) {
 141                 $cat = new self();
 142                 $cat->mTitle = $title;
 143
 144                 # NOTE: the row often results from a LEFT JOIN on categorylinks. This may result in
 145                 #       all the cat_xxx fields being null, if the category page exists, but nothing
 146                 #       was ever added to the category. This case should be treated linke an empty
 147                 #       category, if possible.
 148
 149                 if ( $row->cat_title === null ) {
 150                         if ( $title === null ) {
 151                                 # the name is probably somewhere in the row, for example as page_title,
 152                                 # but we can't know that here...
 153                                 return false;
 154                         } else {
 155                                 $cat->mName = $title->getDBkey(); # if we have a title object, fetch the category name from there
 156                         }
 157
 158                         $cat->mID =   false;
 159                         $cat->mSubcats = 0;
 160                         $cat->mPages   = 0;
 161                         $cat->mFiles   = 0;
 162                 } else {
 163                         $cat->mName    = $row->cat_title;
 164                         $cat->mID      = $row->cat_id;
 165                         $cat->mSubcats = $row->cat_subcats;
 166                         $cat->mPages   = $row->cat_pages;
 167                         $cat->mFiles   = $row->cat_files;
 168                 }
 169
 170                 return $cat;
 171         }
 172
 173         /** @return mixed DB key name, or false on failure */
 174         public function getName() { return $this->getX( 'mName' ); }
 175
 176         /** @return mixed Category ID, or false on failure */
 177         public function getID() { return $this->getX( 'mID' ); }
 178
 179         /** @return mixed Total number of member pages, or false on failure */
 180         public function getPageCount() { return $this->getX( 'mPages' ); }
 181
 182         /** @return mixed Number of subcategories, or false on failure */
 183         public function getSubcatCount() { return $this->getX( 'mSubcats' ); }
 184
 185         /** @return mixed Number of member files, or false on failure */
 186         public function getFileCount() { return $this->getX( 'mFiles' ); }
 187
 188         /**
 189          * @return mixed The Title for this category, or false on failure.
 190          */
 191         public function getTitle() {
 192                 if ( $this->mTitle ) return $this->mTitle;
 193
 194                 if ( !$this->initialize() ) {
 195                         return false;
 196                 }
 197
 198                 $this->mTitle = Title::makeTitleSafe( NS_CATEGORY, $this->mName );
 199                 return $this->mTitle;
 200         }
 201
 202         /**
 203          * Fetch a TitleArray of up to $limit category members, beginning after the
 204          * category sort key $offset.
 205          * @param $limit integer
 206          * @param $offset string
 207          * @return TitleArray object for category members.
 208          */
 209         public function getMembers( $limit = false, $offset = '' ) {
 210                 $dbr = wfGetDB( DB_SLAVE );
 211
 212                 $conds = array( 'cl_to' => $this->getName(), 'cl_from = page_id' );
 213                 $options = array( 'ORDER BY' => 'cl_sortkey' );
 214
 215                 if ( $limit ) {
 216                         $options[ 'LIMIT' ] = $limit;
 217                 }
 218
 219                 if ( $offset !== '' ) {
 220                         $conds[] = 'cl_sortkey > ' . $dbr->addQuotes( $offset );
 221                 }
 222
 223                 return TitleArray::newFromResult(
 224                         $dbr->select(
 225                                 array( 'page', 'categorylinks' ),
 226                                 array( 'page_id', 'page_namespace', 'page_title', 'page_len',
 227                                         'page_is_redirect', 'page_latest' ),
 228                                 $conds,
 229                                 __METHOD__,
 230                                 $options
 231                         )
 232                 );
 233         }
 234
 235         /** Generic accessor */
 236         private function getX( $key ) {
 237                 if ( !$this->initialize() ) {
 238                         return false;
 239                 }
 240                 return $this-> { $key } ;
 241         }
 242
 243         /**
 244          * Refresh the counts for this category.
 245          *
 246          * @return bool True on success, false on failure
 247          */
 248         public function refreshCounts() {
 249                 if ( wfReadOnly() ) {
 250                         return false;
 251                 }
 252                 $dbw = wfGetDB( DB_MASTER );
 253                 $dbw->begin();
 254                 # Note, we must use names for this, since categorylinks does.
 255                 if ( $this->mName === null ) {
 256                         if ( !$this->initialize() ) {
 257                                 return false;
 258                         }
 259                 } else {
 260                         # Let's be sure that the row exists in the table.  We don't need to
 261                         # do this if we got the row from the table in initialization!
 262                         $seqVal = $dbw->nextSequenceValue( 'category_cat_id_seq' );
 263                         $dbw->insert(
 264                                 'category',
 265                                 array(
 266                                         'cat_id' => $seqVal,
 267                                         'cat_title' => $this->mName
 268                                 ),
 269                                 __METHOD__,
 270                                 'IGNORE'
 271                         );
 272                 }
 273
 274                 $cond1 = $dbw->conditional( 'page_namespace=' . NS_CATEGORY, 1, 'NULL' );
 275                 $cond2 = $dbw->conditional( 'page_namespace=' . NS_FILE, 1, 'NULL' );
 276                 $result = $dbw->selectRow(
 277                         array( 'categorylinks', 'page' ),
 278                         array( 'COUNT(*) AS pages',
 279                                    "COUNT($cond1) AS subcats",
 280                                    "COUNT($cond2) AS files"
 281                         ),
 282                         array( 'cl_to' => $this->mName, 'page_id = cl_from' ),
 283                         __METHOD__,
 284                         'LOCK IN SHARE MODE'
 285                 );
 286                 $ret = $dbw->update(
 287                         'category',
 288                         array(
 289                                 'cat_pages' => $result->pages,
 290                                 'cat_subcats' => $result->subcats,
 291                                 'cat_files' => $result->files
 292                         ),
 293                         array( 'cat_title' => $this->mName ),
 294                         __METHOD__
 295                 );
 296                 $dbw->commit();
 297
 298                 # Now we should update our local counts.
 299                 $this->mPages   = $result->pages;
 300                 $this->mSubcats = $result->subcats;
 301                 $this->mFiles   = $result->files;
 302
 303                 return $ret;
 304         }
 305 }