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->mID === null ) {
  29                         throw new MWException( __METHOD__ . ' has both names and IDs null' );
  30                 } elseif ( $this->mID === null ) {
  31                         $where = array( 'cat_title' => $this->mName );
  32                 } elseif ( $this->mName === null ) {
  33                         $where = array( 'cat_id' => $this->mID );
  34                 } else {
  35                         # Already initialized
  36                         return true;
  37                 }
  38                 $dbr = wfGetDB( DB_SLAVE );
  39                 $row = $dbr->selectRow(
  40                         'category',
  41                         array( 'cat_id', 'cat_title', 'cat_pages', 'cat_subcats', 'cat_files' ),
  42                         $where,
  43                         __METHOD__
  44                 );
  45
  46                 if ( !$row ) {
  47                         # Okay, there were no contents.  Nothing to initialize.
  48                         if ( $this->mTitle ) {
  49                                 # If there is a title object but no record in the category table, treat this as an empty category
  50                                 $this->mID      = false;
  51                                 $this->mName    = $this->mTitle->getDBkey();
  52                                 $this->mPages   = 0;
  53                                 $this->mSubcats = 0;
  54                                 $this->mFiles   = 0;
  55
  56                                 return true;
  57                         } else {
  58                                 return false; # Fail
  59                         }
  60                 }
  61
  62                 $this->mID      = $row->cat_id;
  63                 $this->mName    = $row->cat_title;
  64                 $this->mPages   = $row->cat_pages;
  65                 $this->mSubcats = $row->cat_subcats;
  66                 $this->mFiles   = $row->cat_files;
  67
  68                 # (bug 13683) If the count is negative, then 1) it's obviously wrong
  69                 # and should not be kept, and 2) we *probably* don't have to scan many
  70                 # rows to obtain the correct figure, so let's risk a one-time recount.
  71                 if ( $this->mPages < 0 || $this->mSubcats < 0 || $this->mFiles < 0 ) {
  72                         $this->refreshCounts();
  73                 }
  74
  75                 return true;
  76         }
  77
  78         /**
  79          * Factory function.
  80          *
  81          * @param $name Array: A category name (no "Category:" prefix).  It need
  82          *   not be normalized, with spaces replaced by underscores.
  83          * @return mixed Category, or false on a totally invalid name
  84          */
  85         public static function newFromName( $name ) {
  86                 $cat = new self();
  87                 $title = Title::makeTitleSafe( NS_CATEGORY, $name );
  88
  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                 # NOTE: the row often results from a LEFT JOIN on categorylinks. This may result in
 141                 #       all the cat_xxx fields being null, if the category page exists, but nothing
 142                 #       was ever added to the category. This case should be treated linke an empty
 143                 #       category, if possible.
 144
 145                 if ( $row->cat_title === null ) {
 146                         if ( $title === null ) {
 147                                 # the name is probably somewhere in the row, for example as page_title,
 148                                 # but we can't know that here...
 149                                 return false;
 150                         } else {
 151                                 $cat->mName = $title->getDBkey(); # if we have a title object, fetch the category name from there
 152                         }
 153
 154                         $cat->mID =   false;
 155                         $cat->mSubcats = 0;
 156                         $cat->mPages   = 0;
 157                         $cat->mFiles   = 0;
 158                 } else {
 159                         $cat->mName    = $row->cat_title;
 160                         $cat->mID      = $row->cat_id;
 161                         $cat->mSubcats = $row->cat_subcats;
 162                         $cat->mPages   = $row->cat_pages;
 163                         $cat->mFiles   = $row->cat_files;
 164                 }
 165
 166                 return $cat;
 167         }
 168
 169         /** @return mixed DB key name, or false on failure */
 170         public function getName() { return $this->getX( 'mName' ); }
 171
 172         /** @return mixed Category ID, or false on failure */
 173         public function getID() { return $this->getX( 'mID' ); }
 174
 175         /** @return mixed Total number of member pages, or false on failure */
 176         public function getPageCount() { return $this->getX( 'mPages' ); }
 177
 178         /** @return mixed Number of subcategories, or false on failure */
 179         public function getSubcatCount() { return $this->getX( 'mSubcats' ); }
 180
 181         /** @return mixed Number of member files, or false on failure */
 182         public function getFileCount() { return $this->getX( 'mFiles' ); }
 183
 184         /**
 185          * @return mixed The Title for this category, or false on failure.
 186          */
 187         public function getTitle() {
 188                 if ( $this->mTitle ) return $this->mTitle;
 189
 190                 if ( !$this->initialize() ) {
 191                         return false;
 192                 }
 193
 194                 $this->mTitle = Title::makeTitleSafe( NS_CATEGORY, $this->mName );
 195                 return $this->mTitle;
 196         }
 197
 198         /**
 199          * Fetch a TitleArray of up to $limit category members, beginning after the
 200          * category sort key $offset.
 201          * @param $limit integer
 202          * @param $offset string
 203          * @return TitleArray object for category members.
 204          */
 205         public function getMembers( $limit = false, $offset = '' ) {
 206                 $dbr = wfGetDB( DB_SLAVE );
 207
 208                 $conds = array( 'cl_to' => $this->getName(), 'cl_from = page_id' );
 209                 $options = array( 'ORDER BY' => 'cl_sortkey' );
 210
 211                 if ( $limit ) {
 212                         $options[ 'LIMIT' ] = $limit;
 213                 }
 214
 215                 if ( $offset !== '' ) {
 216                         $conds[] = 'cl_sortkey > ' . $dbr->addQuotes( $offset );
 217                 }
 218
 219                 return TitleArray::newFromResult(
 220                         $dbr->select(
 221                                 array( 'page', 'categorylinks' ),
 222                                 array( 'page_id', 'page_namespace', 'page_title', 'page_len',
 223                                         'page_is_redirect', 'page_latest' ),
 224                                 $conds,
 225                                 __METHOD__,
 226                                 $options
 227                         )
 228                 );
 229         }
 230
 231         /** Generic accessor */
 232         private function getX( $key ) {
 233                 if ( !$this->initialize() ) {
 234                         return false;
 235                 }
 236                 return $this-> { $key } ;
 237         }
 238
 239         /**
 240          * Refresh the counts for this category.
 241          *
 242          * @return bool True on success, false on failure
 243          */
 244         public function refreshCounts() {
 245                 if ( wfReadOnly() ) {
 246                         return false;
 247                 }
 248
 249                 # Note, we must use names for this, since categorylinks does.
 250                 if ( $this->mName === null ) {
 251                         if ( !$this->initialize() ) {
 252                                 return false;
 253                         }
 254                 }
 255
 256                 $dbw = wfGetDB( DB_MASTER );
 257                 $dbw->begin();
 258
 259                 # Insert the row if it doesn't exist yet (e.g., this is being run via
 260                 # update.php from a pre-1.16 schema).  TODO: This will cause lots and
 261                 # lots of gaps on some non-MySQL DBMSes if you run populateCategory.php
 262                 # repeatedly.  Plus it's an extra query that's unneeded almost all the
 263                 # time.  This should be rewritten somehow, probably.
 264                 $seqVal = $dbw->nextSequenceValue( 'category_cat_id_seq' );
 265                 $dbw->insert(
 266                         'category',
 267                         array(
 268                                 'cat_id' => $seqVal,
 269                                 'cat_title' => $this->mName
 270                         ),
 271                         __METHOD__,
 272                         'IGNORE'
 273                 );
 274
 275                 $cond1 = $dbw->conditional( 'page_namespace=' . NS_CATEGORY, 1, 'NULL' );
 276                 $cond2 = $dbw->conditional( 'page_namespace=' . NS_FILE, 1, 'NULL' );
 277                 $result = $dbw->selectRow(
 278                         array( 'categorylinks', 'page' ),
 279                         array( 'COUNT(*) AS pages',
 280                                    "COUNT($cond1) AS subcats",
 281                                    "COUNT($cond2) AS files"
 282                         ),
 283                         array( 'cl_to' => $this->mName, 'page_id = cl_from' ),
 284                         __METHOD__,
 285                         'LOCK IN SHARE MODE'
 286                 );
 287                 $ret = $dbw->update(
 288                         'category',
 289                         array(
 290                                 'cat_pages' => $result->pages,
 291                                 'cat_subcats' => $result->subcats,
 292                                 'cat_files' => $result->files
 293                         ),
 294                         array( 'cat_title' => $this->mName ),
 295                         __METHOD__
 296                 );
 297                 $dbw->commit();
 298
 299                 # Now we should update our local counts.
 300                 $this->mPages   = $result->pages;
 301                 $this->mSubcats = $result->subcats;
 302                 $this->mFiles   = $result->files;
 303
 304                 return $ret;
 305         }
 306 }