includes/revisionlist/RevisionListBase.php

   1 <?php
   2 /**
   3  * Holders of revision list for a single page
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  */
  22
  23 use Wikimedia\Rdbms\ResultWrapper;
  24 use Wikimedia\Rdbms\IDatabase;
  25
  26 /**
  27  * List for revision table items for a single page
  28  */
  29 abstract class RevisionListBase extends ContextSource implements Iterator {
  30         /** @var Title */
  31         public $title;
  32
  33         /** @var array */
  34         protected $ids;
  35
  36         /** @var ResultWrapper|bool */
  37         protected $res;
  38
  39         /** @var bool|Revision */
  40         protected $current;
  41
  42         /**
  43          * Construct a revision list for a given title
  44          * @param IContextSource $context
  45          * @param Title $title
  46          */
  47         function __construct( IContextSource $context, Title $title ) {
  48                 $this->setContext( $context );
  49                 $this->title = $title;
  50         }
  51
  52         /**
  53          * Select items only where the ID is any of the specified values
  54          * @param array $ids
  55          */
  56         function filterByIds( array $ids ) {
  57                 $this->ids = $ids;
  58         }
  59
  60         /**
  61          * Get the internal type name of this list. Equal to the table name.
  62          * Override this function.
  63          * @return null
  64          */
  65         public function getType() {
  66                 return null;
  67         }
  68
  69         /**
  70          * Initialise the current iteration pointer
  71          */
  72         protected function initCurrent() {
  73                 $row = $this->res->current();
  74                 if ( $row ) {
  75                         $this->current = $this->newItem( $row );
  76                 } else {
  77                         $this->current = false;
  78                 }
  79         }
  80
  81         /**
  82          * Start iteration. This must be called before current() or next().
  83          * @return Revision First list item
  84          */
  85         public function reset() {
  86                 if ( !$this->res ) {
  87                         $this->res = $this->doQuery( wfGetDB( DB_REPLICA ) );
  88                 } else {
  89                         $this->res->rewind();
  90                 }
  91                 $this->initCurrent();
  92                 return $this->current;
  93         }
  94
  95         public function rewind() {
  96                 $this->reset();
  97         }
  98
  99         /**
 100          * Get the current list item, or false if we are at the end
 101          * @return Revision
 102          */
 103         public function current() {
 104                 return $this->current;
 105         }
 106
 107         /**
 108          * Move the iteration pointer to the next list item, and return it.
 109          * @return Revision
 110          * @suppress PhanParamSignatureMismatchInternal
 111          */
 112         public function next() {
 113                 $this->res->next();
 114                 $this->initCurrent();
 115                 return $this->current;
 116         }
 117
 118         public function key() {
 119                 return $this->res ? $this->res->key() : 0;
 120         }
 121
 122         public function valid() {
 123                 return $this->res ? $this->res->valid() : false;
 124         }
 125
 126         /**
 127          * Get the number of items in the list.
 128          * @return int
 129          */
 130         public function length() {
 131                 if ( !$this->res ) {
 132                         return 0;
 133                 } else {
 134                         return $this->res->numRows();
 135                 }
 136         }
 137
 138         /**
 139          * Do the DB query to iterate through the objects.
 140          * @param IDatabase $db DB object to use for the query
 141          */
 142         abstract public function doQuery( $db );
 143
 144         /**
 145          * Create an item object from a DB result row
 146          * @param object $row
 147          */
 148         abstract public function newItem( $row );
 149 }