IndexPager: Introduce constants for values of $mDefaultDirection

I've spent several hours looking at related code and I still can't
remember which direction is 'true' and which is 'false'.

Change-Id: I58694f7a0892c986e7215f59b56b014cece8d40d

includes/pager/IndexPager.php

@@ -64,6 +64,14 @@
  * @ingroup Pager
  */
 abstract class IndexPager extends ContextSource implements Pager {
+	/**
+	 * Constants for the $mDefaultDirection field.
+	 *
+	 * These are boolean for historical reasons and should stay boolean for backwards-compatibility.
+	 */
+	const DIR_ASCENDING = false;
+	const DIR_DESCENDING = true;
+
 	public $mRequest;
 	public $mLimitsShown = array( 20, 50, 100, 250, 500 );
 	public $mDefaultLimit = 50;
@@ -87,7 +95,7 @@ abstract class IndexPager extends ContextSource implements Pager {
 	protected $mOrderType;
 	/**
 	 * $mDefaultDirection gives the direction to use when sorting results:
-	 * false for ascending, true for descending.  If $mIsBackwards is set, we
+	 * DIR_ASCENDING or DIR_DESCENDING.  If $mIsBackwards is set, we
 	 * start from the opposite end, but we still sort the page itself according
 	 * to $mDefaultDirection.  E.g., if $mDefaultDirection is false but we're
 	 * going backwards, we'll display the last page of results, but the last
@@ -190,6 +198,7 @@ abstract class IndexPager extends ContextSource implements Pager {
 		$fname = __METHOD__ . ' (' . get_class( $this ) . ')';
 		wfProfileIn( $fname );
 
+		// @todo This should probably compare to DIR_DESCENDING and DIR_ASCENDING constants
 		$descending = ( $this->mIsBackwards == $this->mDefaultDirection );
 		# Plus an extra row so that we can tell the "next" link should be shown
 		$queryLimit = $this->mLimit + 1;
@@ -709,8 +718,8 @@ abstract class IndexPager extends ContextSource implements Pager {
 	}
 
 	/**
-	 * Return the default sorting direction: false for ascending, true for
-	 * descending.  You can also have an associative array of ordertype => dir,
+	 * Return the default sorting direction: DIR_ASCENDING or DIR_DESCENDING.
+	 * You can also have an associative array of ordertype => dir,
 	 * if multiple order types are supported.  In this case getIndexField()
 	 * must return an array, and the keys of that must exactly match the keys
 	 * of this.
@@ -728,6 +737,6 @@ abstract class IndexPager extends ContextSource implements Pager {
 	 * @return bool
 	 */
 	protected function getDefaultDirections() {
-		return false;
+		return IndexPager::DIR_ASCENDING;
 	}
 }

includes/pager/ReverseChronologicalPager.php

@@ -26,7 +26,7 @@
  * @ingroup Pager
  */
 abstract class ReverseChronologicalPager extends IndexPager {
-	public $mDefaultDirection = true;
+	public $mDefaultDirection = IndexPager::DIR_DESCENDING;
 	public $mYear;
 	public $mMonth;
 

includes/pager/TablePager.php

@@ -42,9 +42,9 @@ abstract class TablePager extends IndexPager {
 			$this->mSort = $this->getDefaultSort();
 		}
 		if ( $this->getRequest()->getBool( 'asc' ) ) {
-			$this->mDefaultDirection = false;
+			$this->mDefaultDirection = IndexPager::DIR_ASCENDING;
 		} elseif ( $this->getRequest()->getBool( 'desc' ) ) {
-			$this->mDefaultDirection = true;
+			$this->mDefaultDirection = IndexPager::DIR_DESCENDING;
 		} /* Else leave it at whatever the class default is */
 
 		parent::__construct();
@@ -128,7 +128,7 @@ abstract class TablePager extends IndexPager {
 				if ( $this->mSort == $field ) {
 					// The table is sorted by this field already, make a link to sort in the other direction
 					// We don't actually know in which direction other fields will be sorted by default…
-					if ( $this->mDefaultDirection ) {
+					if ( $this->mDefaultDirection == IndexPager::DIR_DESCENDING ) {
 						$linkType = 'asc';
 						$class = "$sortClass TablePager_sort-descending";
 						$query['asc'] = '1';

includes/specials/SpecialAllMessages.php

@@ -101,7 +101,7 @@ class AllMessagesTablePager extends TablePager {
 		$this->mIndexField = 'am_title';
 		$this->mPage = $page;
 		$this->mConds = $conds;
-		$this->mDefaultDirection = true; // always sort ascending
+		$this->mDefaultDirection = IndexPager::DIR_ASCENDING;
 		$this->mLimitsShown = array( 20, 50, 100, 250, 500, 5000 );
 
 		global $wgContLang;

includes/specials/SpecialBlockList.php

@@ -224,7 +224,7 @@ class BlockListPager extends TablePager {
 	function __construct( $page, $conds ) {
 		$this->page = $page;
 		$this->conds = $conds;
-		$this->mDefaultDirection = true;
+		$this->mDefaultDirection = IndexPager::DIR_ASCENDING;
 		parent::__construct( $page->getContext() );
 	}
 

includes/specials/SpecialContributions.php

@@ -652,7 +652,7 @@ class SpecialContributions extends IncludableSpecialPage {
  * @ingroup SpecialPage Pager
  */
 class ContribsPager extends ReverseChronologicalPager {
-	public $mDefaultDirection = true;
+	public $mDefaultDirection = IndexPager::DIR_ASCENDING;
 	public $messages;
 	public $target;
 	public $namespace = '';

includes/specials/SpecialDeletedContributions.php

@@ -26,7 +26,7 @@
  * @ingroup SpecialPage
  */
 class DeletedContribsPager extends IndexPager {
-	public $mDefaultDirection = true;
+	public $mDefaultDirection = IndexPager::DIR_ASCENDING;
 	public $messages;
 	public $target;
 	public $namespace = '';

includes/specials/SpecialListfiles.php

@@ -108,12 +108,12 @@ class ImageListPager extends TablePager {
 
 		if ( !$including ) {
 			if ( $context->getRequest()->getText( 'sort', 'img_date' ) == 'img_date' ) {
-				$this->mDefaultDirection = true;
+				$this->mDefaultDirection = IndexPager::DIR_ASCENDING;
 			} else {
-				$this->mDefaultDirection = false;
+				$this->mDefaultDirection = IndexPager::DIR_DESCENDING;
 			}
 		} else {
-			$this->mDefaultDirection = true;
+			$this->mDefaultDirection = IndexPager::DIR_ASCENDING;
 		}
 
 		parent::__construct( $context );

includes/specials/SpecialListusers.php

@@ -69,7 +69,9 @@ class UsersPager extends AlphabeticPager {
 		$this->editsOnly = $request->getBool( 'editsOnly' );
 		$this->creationSort = $request->getBool( 'creationSort' );
 		$this->including = $including;
-		$this->mDefaultDirection = $request->getBool( 'desc' );
+		$this->mDefaultDirection = $request->getBool( 'desc' )
+			? IndexPager::DIR_DESCENDING
+			: IndexPager::DIR_ASCENDING;
 
 		$this->requestedUser = '';