Awight has uploaded a new change for review.

  https://gerrit.wikimedia.org/r/166357

Change subject: WIP componentize Title permissions logic
......................................................................

WIP componentize Title permissions logic

Move Title code dealing with permissions and restrictions into the
new security component.

See 
https://www.mediawiki.org/wiki/Requests_for_comment/Page_protection_as_a_component

TODO:
* Decide whether deprecated public properties are an issue.
* Verify test coverage.

Change-Id: Ifa5671f5e4cf16cf5447bf132b5081af95e543ee
---
M includes/AutoLoader.php
M includes/Title.php
A includes/security/TitleSecurity.php
3 files changed, 1,260 insertions(+), 987 deletions(-)


  git pull ssh://gerrit.wikimedia.org:29418/mediawiki/core 
refs/changes/57/166357/1

diff --git a/includes/AutoLoader.php b/includes/AutoLoader.php
index 2a45fc3..61ba642 100644
--- a/includes/AutoLoader.php
+++ b/includes/AutoLoader.php
@@ -168,6 +168,7 @@
        'TitleArray' => 'includes/TitleArray.php',
        'TitleArrayFromResult' => 'includes/TitleArrayFromResult.php',
        'TitlePrefixSearch' => 'includes/PrefixSearch.php',
+       'TitleSecurity' => 'includes/security/TitleSecurity.php',
        'UploadSourceAdapter' => 'includes/Import.php',
        'UppercaseCollation' => 'includes/Collation.php',
        'User' => 'includes/User.php',
diff --git a/includes/Title.php b/includes/Title.php
index e8cda85..85f8c03 100644
--- a/includes/Title.php
+++ b/includes/Title.php
@@ -68,6 +68,9 @@
        /** @var string Database key with the initial letter in the case 
specified by the user */
        protected $mUserCaseDBKey;
 
+       /** @var string Text form including namespace/interwiki, initialised on 
demand */
+       protected $mPrefixedText;
+
        /** @var int Namespace index, i.e. one of the NS_xxxx constants */
        public $mNamespace = NS_MAIN;
 
@@ -94,36 +97,6 @@
 
        /** @var int Estimated number of revisions; null of not loaded */
        private $mEstimateRevisions;
-
-       /** @var array Array of groups allowed to edit this article */
-       public $mRestrictions = array();
-
-       /** @var bool */
-       protected $mOldRestrictions = false;
-
-       /** @var bool Cascade restrictions on this page to included templates 
and images? */
-       public $mCascadeRestriction;
-
-       /** Caching the results of getCascadeProtectionSources */
-       public $mCascadingRestrictions;
-
-       /** @var array When do the restrictions on this page expire? */
-       protected $mRestrictionsExpiry = array();
-
-       /** @var bool Are cascading restrictions in effect on this page? */
-       protected $mHasCascadingRestrictions;
-
-       /** @var array Where are the cascading restrictions coming from on this 
page? */
-       public $mCascadeSources;
-
-       /** @var bool Boolean for initialisation on demand */
-       public $mRestrictionsLoaded = false;
-
-       /** @var string Text form including namespace/interwiki, initialised on 
demand */
-       protected $mPrefixedText = null;
-
-       /** @var mixed Cached value for getTitleProtection (create protection) 
*/
-       public $mTitleProtection;
 
        /**
         * @var int Namespace index when there is no namespace. Don't change the
@@ -161,6 +134,9 @@
 
        /** @var bool Would deleting this page be a big deletion? */
        private $mIsBigDeletion = null;
+
+       /** @var TitleSecurity manages protection and restrictions */
+       protected $mTitleSecurity;
        // @}
 
        /**
@@ -1869,7 +1845,7 @@
         * @return bool
         */
        public function quickUserCan( $action, $user = null ) {
-               return $this->userCan( $action, $user, false );
+               return $this->getTitleSecurity()->quickUserCan( $this, $action, 
$user );
        }
 
        /**
@@ -1883,13 +1859,7 @@
         * @return bool
         */
        public function userCan( $action, $user = null, $doExpensiveQueries = 
true ) {
-               if ( !$user instanceof User ) {
-                       global $wgUser;
-                       $user = $wgUser;
-               }
-
-               return !count( $this->getUserPermissionsErrorsInternal(
-                       $action, $user, $doExpensiveQueries, true ) );
+               return $this->getTitleSecurity()->userCan( $this, $action, 
$user, $doExpensiveQueries );
        }
 
        /**
@@ -1908,579 +1878,9 @@
        public function getUserPermissionsErrors( $action, $user, 
$doExpensiveQueries = true,
                $ignoreErrors = array()
        ) {
-               $errors = $this->getUserPermissionsErrorsInternal( $action, 
$user, $doExpensiveQueries );
-
-               // Remove the errors being ignored.
-               foreach ( $errors as $index => $error ) {
-                       $error_key = is_array( $error ) ? $error[0] : $error;
-
-                       if ( in_array( $error_key, $ignoreErrors ) ) {
-                               unset( $errors[$index] );
-                       }
-               }
-
-               return $errors;
-       }
-
-       /**
-        * Permissions checks that fail most often, and which are easiest to 
test.
-        *
-        * @param string $action The action to check
-        * @param User $user User to check
-        * @param array $errors List of current errors
-        * @param bool $doExpensiveQueries Whether or not to perform expensive 
queries
-        * @param bool $short Short circuit on first error
-        *
-        * @return array List of errors
-        */
-       private function checkQuickPermissions( $action, $user, $errors,
-               $doExpensiveQueries, $short
-       ) {
-               if ( !wfRunHooks( 'TitleQuickPermissions',
-                       array( $this, $user, $action, &$errors, 
$doExpensiveQueries, $short ) )
-               ) {
-                       return $errors;
-               }
-
-               if ( $action == 'create' ) {
-                       if (
-                               ( $this->isTalkPage() && !$user->isAllowed( 
'createtalk' ) ) ||
-                               ( !$this->isTalkPage() && !$user->isAllowed( 
'createpage' ) )
-                       ) {
-                               $errors[] = $user->isAnon() ? array( 
'nocreatetext' ) : array( 'nocreate-loggedin' );
-                       }
-               } elseif ( $action == 'move' ) {
-                       if ( !$user->isAllowed( 'move-rootuserpages' )
-                                       && $this->mNamespace == NS_USER && 
!$this->isSubpage() ) {
-                               // Show user page-specific message only if the 
user can move other pages
-                               $errors[] = array( 'cant-move-user-page' );
-                       }
-
-                       // Check if user is allowed to move files if it's a file
-                       if ( $this->mNamespace == NS_FILE && !$user->isAllowed( 
'movefile' ) ) {
-                               $errors[] = array( 'movenotallowedfile' );
-                       }
-
-                       // Check if user is allowed to move category pages if 
it's a category page
-                       if ( $this->mNamespace == NS_CATEGORY && 
!$user->isAllowed( 'move-categorypages' ) ) {
-                               $errors[] = array( 'cant-move-category-page' );
-                       }
-
-                       if ( !$user->isAllowed( 'move' ) ) {
-                               // User can't move anything
-                               $userCanMove = User::groupHasPermission( 
'user', 'move' );
-                               $autoconfirmedCanMove = 
User::groupHasPermission( 'autoconfirmed', 'move' );
-                               if ( $user->isAnon() && ( $userCanMove || 
$autoconfirmedCanMove ) ) {
-                                       // custom message if logged-in users 
without any special rights can move
-                                       $errors[] = array( 'movenologintext' );
-                               } else {
-                                       $errors[] = array( 'movenotallowed' );
-                               }
-                       }
-               } elseif ( $action == 'move-target' ) {
-                       if ( !$user->isAllowed( 'move' ) ) {
-                               // User can't move anything
-                               $errors[] = array( 'movenotallowed' );
-                       } elseif ( !$user->isAllowed( 'move-rootuserpages' )
-                                       && $this->mNamespace == NS_USER && 
!$this->isSubpage() ) {
-                               // Show user page-specific message only if the 
user can move other pages
-                               $errors[] = array( 'cant-move-to-user-page' );
-                       } elseif ( !$user->isAllowed( 'move-categorypages' )
-                                       && $this->mNamespace == NS_CATEGORY ) {
-                               // Show category page-specific message only if 
the user can move other pages
-                               $errors[] = array( 'cant-move-to-category-page' 
);
-                       }
-               } elseif ( !$user->isAllowed( $action ) ) {
-                       $errors[] = $this->missingPermissionError( $action, 
$short );
-               }
-
-               return $errors;
-       }
-
-       /**
-        * Add the resulting error code to the errors array
-        *
-        * @param array $errors List of current errors
-        * @param array $result Result of errors
-        *
-        * @return array List of errors
-        */
-       private function resultToError( $errors, $result ) {
-               if ( is_array( $result ) && count( $result ) && !is_array( 
$result[0] ) ) {
-                       // A single array representing an error
-                       $errors[] = $result;
-               } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
-                       // A nested array representing multiple errors
-                       $errors = array_merge( $errors, $result );
-               } elseif ( $result !== '' && is_string( $result ) ) {
-                       // A string representing a message-id
-                       $errors[] = array( $result );
-               } elseif ( $result === false ) {
-                       // a generic "We don't want them to do that"
-                       $errors[] = array( 'badaccess-group0' );
-               }
-               return $errors;
-       }
-
-       /**
-        * Check various permission hooks
-        *
-        * @param string $action The action to check
-        * @param User $user User to check
-        * @param array $errors List of current errors
-        * @param bool $doExpensiveQueries Whether or not to perform expensive 
queries
-        * @param bool $short Short circuit on first error
-        *
-        * @return array List of errors
-        */
-       private function checkPermissionHooks( $action, $user, $errors, 
$doExpensiveQueries, $short ) {
-               // Use getUserPermissionsErrors instead
-               $result = '';
-               if ( !wfRunHooks( 'userCan', array( &$this, &$user, $action, 
&$result ) ) ) {
-                       return $result ? array() : array( array( 
'badaccess-group0' ) );
-               }
-               // Check getUserPermissionsErrors hook
-               if ( !wfRunHooks( 'getUserPermissionsErrors', array( &$this, 
&$user, $action, &$result ) ) ) {
-                       $errors = $this->resultToError( $errors, $result );
-               }
-               // Check getUserPermissionsErrorsExpensive hook
-               if (
-                       $doExpensiveQueries
-                       && !( $short && count( $errors ) > 0 )
-                       && !wfRunHooks( 'getUserPermissionsErrorsExpensive', 
array( &$this, &$user, $action, &$result ) )
-               ) {
-                       $errors = $this->resultToError( $errors, $result );
-               }
-
-               return $errors;
-       }
-
-       /**
-        * Check permissions on special pages & namespaces
-        *
-        * @param string $action The action to check
-        * @param User $user User to check
-        * @param array $errors List of current errors
-        * @param bool $doExpensiveQueries Whether or not to perform expensive 
queries
-        * @param bool $short Short circuit on first error
-        *
-        * @return array List of errors
-        */
-       private function checkSpecialsAndNSPermissions( $action, $user, $errors,
-               $doExpensiveQueries, $short
-       ) {
-               # Only 'createaccount' can be performed on special pages,
-               # which don't actually exist in the DB.
-               if ( NS_SPECIAL == $this->mNamespace && $action !== 
'createaccount' ) {
-                       $errors[] = array( 'ns-specialprotected' );
-               }
-
-               # Check $wgNamespaceProtection for restricted namespaces
-               if ( $this->isNamespaceProtected( $user ) ) {
-                       $ns = $this->mNamespace == NS_MAIN ?
-                               wfMessage( 'nstab-main' )->text() : 
$this->getNsText();
-                       $errors[] = $this->mNamespace == NS_MEDIAWIKI ?
-                               array( 'protectedinterface', $action ) : array( 
'namespaceprotected', $ns, $action );
-               }
-
-               return $errors;
-       }
-
-       /**
-        * Check CSS/JS sub-page permissions
-        *
-        * @param string $action The action to check
-        * @param User $user User to check
-        * @param array $errors List of current errors
-        * @param bool $doExpensiveQueries Whether or not to perform expensive 
queries
-        * @param bool $short Short circuit on first error
-        *
-        * @return array List of errors
-        */
-       private function checkCSSandJSPermissions( $action, $user, $errors, 
$doExpensiveQueries, $short ) {
-               # Protect css/js subpages of user pages
-               # XXX: this might be better using restrictions
-               # XXX: right 'editusercssjs' is deprecated, for backward 
compatibility only
-               if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' 
) ) {
-                       if ( preg_match( '/^' . preg_quote( $user->getName(), 
'/' ) . '\//', $this->mTextform ) ) {
-                               if ( $this->isCssSubpage() && 
!$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
-                                       $errors[] = array( 
'mycustomcssprotected', $action );
-                               } elseif ( $this->isJsSubpage() && 
!$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
-                                       $errors[] = array( 
'mycustomjsprotected', $action );
-                               }
-                       } else {
-                               if ( $this->isCssSubpage() && 
!$user->isAllowed( 'editusercss' ) ) {
-                                       $errors[] = array( 
'customcssprotected', $action );
-                               } elseif ( $this->isJsSubpage() && 
!$user->isAllowed( 'edituserjs' ) ) {
-                                       $errors[] = array( 'customjsprotected', 
$action );
-                               }
-                       }
-               }
-
-               return $errors;
-       }
-
-       /**
-        * Check against page_restrictions table requirements on this
-        * page. The user must possess all required rights for this
-        * action.
-        *
-        * @param string $action The action to check
-        * @param User $user User to check
-        * @param array $errors List of current errors
-        * @param bool $doExpensiveQueries Whether or not to perform expensive 
queries
-        * @param bool $short Short circuit on first error
-        *
-        * @return array List of errors
-        */
-       private function checkPageRestrictions( $action, $user, $errors, 
$doExpensiveQueries, $short ) {
-               foreach ( $this->getRestrictions( $action ) as $right ) {
-                       // Backwards compatibility, rewrite sysop -> 
editprotected
-                       if ( $right == 'sysop' ) {
-                               $right = 'editprotected';
-                       }
-                       // Backwards compatibility, rewrite autoconfirmed -> 
editsemiprotected
-                       if ( $right == 'autoconfirmed' ) {
-                               $right = 'editsemiprotected';
-                       }
-                       if ( $right == '' ) {
-                               continue;
-                       }
-                       if ( !$user->isAllowed( $right ) ) {
-                               $errors[] = array( 'protectedpagetext', $right, 
$action );
-                       } elseif ( $this->mCascadeRestriction && 
!$user->isAllowed( 'protect' ) ) {
-                               $errors[] = array( 'protectedpagetext', 
'protect', $action );
-                       }
-               }
-
-               return $errors;
-       }
-
-       /**
-        * Check restrictions on cascading pages.
-        *
-        * @param string $action The action to check
-        * @param User $user User to check
-        * @param array $errors List of current errors
-        * @param bool $doExpensiveQueries Whether or not to perform expensive 
queries
-        * @param bool $short Short circuit on first error
-        *
-        * @return array List of errors
-        */
-       private function checkCascadingSourcesRestrictions( $action, $user, 
$errors,
-               $doExpensiveQueries, $short
-       ) {
-               if ( $doExpensiveQueries && !$this->isCssJsSubpage() ) {
-                       # We /could/ use the protection level on the source 
page, but it's
-                       # fairly ugly as we have to establish a precedence 
hierarchy for pages
-                       # included by multiple cascade-protected pages. So just 
restrict
-                       # it to people with 'protect' permission, as they could 
remove the
-                       # protection anyway.
-                       list( $cascadingSources, $restrictions ) = 
$this->getCascadeProtectionSources();
-                       # Cascading protection depends on more than this page...
-                       # Several cascading protected pages may include this 
page...
-                       # Check each cascading level
-                       # This is only for protection restrictions, not for all 
actions
-                       if ( isset( $restrictions[$action] ) ) {
-                               foreach ( $restrictions[$action] as $right ) {
-                                       // Backwards compatibility, rewrite 
sysop -> editprotected
-                                       if ( $right == 'sysop' ) {
-                                               $right = 'editprotected';
-                                       }
-                                       // Backwards compatibility, rewrite 
autoconfirmed -> editsemiprotected
-                                       if ( $right == 'autoconfirmed' ) {
-                                               $right = 'editsemiprotected';
-                                       }
-                                       if ( $right != '' && 
!$user->isAllowedAll( 'protect', $right ) ) {
-                                               $pages = '';
-                                               foreach ( $cascadingSources as 
$page ) {
-                                                       $pages .= '* [[:' . 
$page->getPrefixedText() . "]]\n";
-                                               }
-                                               $errors[] = array( 
'cascadeprotected', count( $cascadingSources ), $pages, $action );
-                                       }
-                               }
-                       }
-               }
-
-               return $errors;
-       }
-
-       /**
-        * Check action permissions not already checked in checkQuickPermissions
-        *
-        * @param string $action The action to check
-        * @param User $user User to check
-        * @param array $errors List of current errors
-        * @param bool $doExpensiveQueries Whether or not to perform expensive 
queries
-        * @param bool $short Short circuit on first error
-        *
-        * @return array List of errors
-        */
-       private function checkActionPermissions( $action, $user, $errors,
-               $doExpensiveQueries, $short
-       ) {
-               global $wgDeleteRevisionsLimit, $wgLang;
-
-               if ( $action == 'protect' ) {
-                       if ( count( $this->getUserPermissionsErrorsInternal( 
'edit',
-                               $user, $doExpensiveQueries, true ) )
-                       ) {
-                               // If they can't edit, they shouldn't protect.
-                               $errors[] = array( 'protect-cantedit' );
-                       }
-               } elseif ( $action == 'create' ) {
-                       $title_protection = $this->getTitleProtection();
-                       if ( $title_protection ) {
-                               if ( $title_protection['pt_create_perm'] == 
'sysop' ) {
-                                       $title_protection['pt_create_perm'] = 
'editprotected'; // B/C
-                               }
-                               if ( $title_protection['pt_create_perm'] == 
'autoconfirmed' ) {
-                                       $title_protection['pt_create_perm'] = 
'editsemiprotected'; // B/C
-                               }
-                               if ( $title_protection['pt_create_perm'] == ''
-                                       || !$user->isAllowed( 
$title_protection['pt_create_perm'] )
-                               ) {
-                                       $errors[] = array(
-                                               'titleprotected',
-                                               User::whoIs( 
$title_protection['pt_user'] ),
-                                               $title_protection['pt_reason']
-                                       );
-                               }
-                       }
-               } elseif ( $action == 'move' ) {
-                       // Check for immobile pages
-                       if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
-                               // Specific message for this case
-                               $errors[] = array( 'immobile-source-namespace', 
$this->getNsText() );
-                       } elseif ( !$this->isMovable() ) {
-                               // Less specific message for rarer cases
-                               $errors[] = array( 'immobile-source-page' );
-                       }
-               } elseif ( $action == 'move-target' ) {
-                       if ( !MWNamespace::isMovable( $this->mNamespace ) ) {
-                               $errors[] = array( 'immobile-target-namespace', 
$this->getNsText() );
-                       } elseif ( !$this->isMovable() ) {
-                               $errors[] = array( 'immobile-target-page' );
-                       }
-               } elseif ( $action == 'delete' ) {
-                       $tempErrors = $this->checkPageRestrictions( 'edit',
-                               $user, array(), $doExpensiveQueries, true );
-                       if ( !$tempErrors ) {
-                               $tempErrors = 
$this->checkCascadingSourcesRestrictions( 'edit',
-                                       $user, $tempErrors, 
$doExpensiveQueries, true );
-                       }
-                       if ( $tempErrors ) {
-                               // If protection keeps them from editing, they 
shouldn't be able to delete.
-                               $errors[] = array( 'deleteprotected' );
-                       }
-                       if ( $doExpensiveQueries && $wgDeleteRevisionsLimit
-                               && !$this->userCan( 'bigdelete', $user ) && 
$this->isBigDeletion()
-                       ) {
-                               $errors[] = array( 'delete-toobig', 
$wgLang->formatNum( $wgDeleteRevisionsLimit ) );
-                       }
-               }
-               return $errors;
-       }
-
-       /**
-        * Check that the user isn't blocked from editing.
-        *
-        * @param string $action The action to check
-        * @param User $user User to check
-        * @param array $errors List of current errors
-        * @param bool $doExpensiveQueries Whether or not to perform expensive 
queries
-        * @param bool $short Short circuit on first error
-        *
-        * @return array List of errors
-        */
-       private function checkUserBlock( $action, $user, $errors, 
$doExpensiveQueries, $short ) {
-               // Account creation blocks handled at userlogin.
-               // Unblocking handled in SpecialUnblock
-               if ( !$doExpensiveQueries || in_array( $action, array( 
'createaccount', 'unblock' ) ) ) {
-                       return $errors;
-               }
-
-               global $wgEmailConfirmToEdit;
-
-               if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
-                       $errors[] = array( 'confirmedittext' );
-               }
-
-               if ( ( $action == 'edit' || $action == 'create' ) && 
!$user->isBlockedFrom( $this ) ) {
-                       // Don't block the user from editing their own talk 
page unless they've been
-                       // explicitly blocked from that too.
-               } elseif ( $user->isBlocked() && $user->mBlock->prevents( 
$action ) !== false ) {
-                       // @todo FIXME: Pass the relevant context into this 
function.
-                       $errors[] = $user->getBlock()->getPermissionsError( 
RequestContext::getMain() );
-               }
-
-               return $errors;
-       }
-
-       /**
-        * Check that the user is allowed to read this page.
-        *
-        * @param string $action The action to check
-        * @param User $user User to check
-        * @param array $errors List of current errors
-        * @param bool $doExpensiveQueries Whether or not to perform expensive 
queries
-        * @param bool $short Short circuit on first error
-        *
-        * @return array List of errors
-        */
-       private function checkReadPermissions( $action, $user, $errors, 
$doExpensiveQueries, $short ) {
-               global $wgWhitelistRead, $wgWhitelistReadRegexp;
-
-               $whitelisted = false;
-               if ( User::isEveryoneAllowed( 'read' ) ) {
-                       # Shortcut for public wikis, allows skipping quite a 
bit of code
-                       $whitelisted = true;
-               } elseif ( $user->isAllowed( 'read' ) ) {
-                       # If the user is allowed to read pages, he is allowed 
to read all pages
-                       $whitelisted = true;
-               } elseif ( $this->isSpecial( 'Userlogin' )
-                       || $this->isSpecial( 'ChangePassword' )
-                       || $this->isSpecial( 'PasswordReset' )
-               ) {
-                       # Always grant access to the login page.
-                       # Even anons need to be able to log in.
-                       $whitelisted = true;
-               } elseif ( is_array( $wgWhitelistRead ) && count( 
$wgWhitelistRead ) ) {
-                       # Time to check the whitelist
-                       # Only do these checks is there's something to check 
against
-                       $name = $this->getPrefixedText();
-                       $dbName = $this->getPrefixedDBkey();
-
-                       // Check for explicit whitelisting with and without 
underscores
-                       if ( in_array( $name, $wgWhitelistRead, true ) || 
in_array( $dbName, $wgWhitelistRead, true ) ) {
-                               $whitelisted = true;
-                       } elseif ( $this->getNamespace() == NS_MAIN ) {
-                               # Old settings might have the title prefixed 
with
-                               # a colon for main-namespace pages
-                               if ( in_array( ':' . $name, $wgWhitelistRead ) 
) {
-                                       $whitelisted = true;
-                               }
-                       } elseif ( $this->isSpecialPage() ) {
-                               # If it's a special page, ditch the subpage bit 
and check again
-                               $name = $this->getDBkey();
-                               list( $name, /* $subpage */ ) = 
SpecialPageFactory::resolveAlias( $name );
-                               if ( $name ) {
-                                       $pure = SpecialPage::getTitleFor( $name 
)->getPrefixedText();
-                                       if ( in_array( $pure, $wgWhitelistRead, 
true ) ) {
-                                               $whitelisted = true;
-                                       }
-                               }
-                       }
-               }
-
-               if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && 
!empty( $wgWhitelistReadRegexp ) ) {
-                       $name = $this->getPrefixedText();
-                       // Check for regex whitelisting
-                       foreach ( $wgWhitelistReadRegexp as $listItem ) {
-                               if ( preg_match( $listItem, $name ) ) {
-                                       $whitelisted = true;
-                                       break;
-                               }
-                       }
-               }
-
-               if ( !$whitelisted ) {
-                       # If the title is not whitelisted, give extensions a 
chance to do so...
-                       wfRunHooks( 'TitleReadWhitelist', array( $this, $user, 
&$whitelisted ) );
-                       if ( !$whitelisted ) {
-                               $errors[] = $this->missingPermissionError( 
$action, $short );
-                       }
-               }
-
-               return $errors;
-       }
-
-       /**
-        * Get a description array when the user doesn't have the right to 
perform
-        * $action (i.e. when User::isAllowed() returns false)
-        *
-        * @param string $action The action to check
-        * @param bool $short Short circuit on first error
-        * @return array List of errors
-        */
-       private function missingPermissionError( $action, $short ) {
-               // We avoid expensive display logic for quickUserCan's and such
-               if ( $short ) {
-                       return array( 'badaccess-group0' );
-               }
-
-               $groups = array_map( array( 'User', 'makeGroupLinkWiki' ),
-                       User::getGroupsWithPermission( $action ) );
-
-               if ( count( $groups ) ) {
-                       global $wgLang;
-                       return array(
-                               'badaccess-groups',
-                               $wgLang->commaList( $groups ),
-                               count( $groups )
-                       );
-               } else {
-                       return array( 'badaccess-group0' );
-               }
-       }
-
-       /**
-        * Can $user perform $action on this page? This is an internal function,
-        * which checks ONLY that previously checked by userCan (i.e. it leaves 
out
-        * checks on wfReadOnly() and blocks)
-        *
-        * @param string $action Action that permission needs to be checked for
-        * @param User $user User to check
-        * @param bool $doExpensiveQueries Set this to false to avoid doing 
unnecessary queries.
-        * @param bool $short Set this to true to stop after the first 
permission error.
-        * @return array Array of arrays of the arguments to wfMessage to 
explain permissions problems.
-        */
-       protected function getUserPermissionsErrorsInternal( $action, $user,
-               $doExpensiveQueries = true, $short = false
-       ) {
-               wfProfileIn( __METHOD__ );
-
-               # Read has special handling
-               if ( $action == 'read' ) {
-                       $checks = array(
-                               'checkPermissionHooks',
-                               'checkReadPermissions',
-                       );
-               # Don't call checkSpecialsAndNSPermissions or 
checkCSSandJSPermissions
-               # here as it will lead to duplicate error messages. This is 
okay to do
-               # since anywhere that checks for create will also check for 
edit, and
-               # those checks are called for edit.
-               } elseif ( $action == 'create' ) {
-                       $checks = array(
-                               'checkQuickPermissions',
-                               'checkPermissionHooks',
-                               'checkPageRestrictions',
-                               'checkCascadingSourcesRestrictions',
-                               'checkActionPermissions',
-                               'checkUserBlock'
-                       );
-               } else {
-                       $checks = array(
-                               'checkQuickPermissions',
-                               'checkPermissionHooks',
-                               'checkSpecialsAndNSPermissions',
-                               'checkCSSandJSPermissions',
-                               'checkPageRestrictions',
-                               'checkCascadingSourcesRestrictions',
-                               'checkActionPermissions',
-                               'checkUserBlock'
-                       );
-               }
-
-               $errors = array();
-               while ( count( $checks ) > 0 &&
-                               !( $short && count( $errors ) > 0 ) ) {
-                       $method = array_shift( $checks );
-                       $errors = $this->$method( $action, $user, $errors, 
$doExpensiveQueries, $short );
-               }
-
-               wfProfileOut( __METHOD__ );
-               return $errors;
+               return $this->getTitleSecurity()->getUserPermissionsErrors(
+                       $action, $user, $doExpensiveQueries, $ignoreErrors
+               );
        }
 
        /**
@@ -2491,16 +1891,7 @@
         * @return array
         */
        public static function getFilteredRestrictionTypes( $exists = true ) {
-               global $wgRestrictionTypes;
-               $types = $wgRestrictionTypes;
-               if ( $exists ) {
-                       # Remove the create restriction for existing titles
-                       $types = array_diff( $types, array( 'create' ) );
-               } else {
-                       # Only the create and upload restrictions apply to 
non-existing titles
-                       $types = array_intersect( $types, array( 'create', 
'upload' ) );
-               }
-               return $types;
+               return $this->getTitleSecurity()->getFilteredRestrictionTypes( 
$exists );
        }
 
        /**
@@ -2509,70 +1900,14 @@
         * @return array Applicable restriction types
         */
        public function getRestrictionTypes() {
-               if ( $this->isSpecialPage() ) {
-                       return array();
-               }
-
-               $types = self::getFilteredRestrictionTypes( $this->exists() );
-
-               if ( $this->getNamespace() != NS_FILE ) {
-                       # Remove the upload restriction for non-file titles
-                       $types = array_diff( $types, array( 'upload' ) );
-               }
-
-               wfRunHooks( 'TitleGetRestrictionTypes', array( $this, &$types ) 
);
-
-               wfDebug( __METHOD__ . ': applicable restrictions to [[' .
-                       $this->getPrefixedText() . ']] are {' . implode( ',', 
$types ) . "}\n" );
-
-               return $types;
-       }
-
-       /**
-        * Is this title subject to title protection?
-        * Title protection is the one applied against creation of such title.
-        *
-        * @return array|bool An associative array representing any existent 
title
-        *   protection, or false if there's none.
-        */
-       private function getTitleProtection() {
-               // Can't protect pages in special namespaces
-               if ( $this->getNamespace() < 0 ) {
-                       return false;
-               }
-
-               // Can't protect pages that exist.
-               if ( $this->exists() ) {
-                       return false;
-               }
-
-               if ( $this->mTitleProtection === null ) {
-                       $dbr = wfGetDB( DB_SLAVE );
-                       $res = $dbr->select(
-                               'protected_titles',
-                               array( 'pt_user', 'pt_reason', 'pt_expiry', 
'pt_create_perm' ),
-                               array( 'pt_namespace' => $this->getNamespace(), 
'pt_title' => $this->getDBkey() ),
-                               __METHOD__
-                       );
-
-                       // fetchRow returns false if there are no rows.
-                       $this->mTitleProtection = $dbr->fetchRow( $res );
-               }
-               return $this->mTitleProtection;
+               return $this->getTitleSecurity()->getRestrictionTypes( $this );
        }
 
        /**
         * Remove any title protection due to page existing
         */
        public function deleteTitleProtection() {
-               $dbw = wfGetDB( DB_MASTER );
-
-               $dbw->delete(
-                       'protected_titles',
-                       array( 'pt_namespace' => $this->getNamespace(), 
'pt_title' => $this->getDBkey() ),
-                       __METHOD__
-               );
-               $this->mTitleProtection = false;
+               $this->getTitleSecurity()->deleteTitleProtection( $this );
        }
 
        /**
@@ -2583,24 +1918,7 @@
         * @return bool
         */
        public function isSemiProtected( $action = 'edit' ) {
-               global $wgSemiprotectedRestrictionLevels;
-
-               $restrictions = $this->getRestrictions( $action );
-               $semi = $wgSemiprotectedRestrictionLevels;
-               if ( !$restrictions || !$semi ) {
-                       // Not protected, or all protection is full protection
-                       return false;
-               }
-
-               // Remap autoconfirmed to editsemiprotected for BC
-               foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
-                       $semi[$key] = 'editsemiprotected';
-               }
-               foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key 
) {
-                       $restrictions[$key] = 'editsemiprotected';
-               }
-
-               return !array_diff( $restrictions, $semi );
+               return $this->getTitleSecurity()->isSemiProtected( $this, 
$action );
        }
 
        /**
@@ -2611,28 +1929,7 @@
         * @return bool
         */
        public function isProtected( $action = '' ) {
-               global $wgRestrictionLevels;
-
-               $restrictionTypes = $this->getRestrictionTypes();
-
-               # Special pages have inherent protection
-               if ( $this->isSpecialPage() ) {
-                       return true;
-               }
-
-               # Check regular protection levels
-               foreach ( $restrictionTypes as $type ) {
-                       if ( $action == $type || $action == '' ) {
-                               $r = $this->getRestrictions( $type );
-                               foreach ( $wgRestrictionLevels as $level ) {
-                                       if ( in_array( $level, $r ) && $level 
!= '' ) {
-                                               return true;
-                                       }
-                               }
-                       }
-               }
-
-               return false;
+               return $this->getTitleSecurity()->isProtected( $this, $action );
        }
 
        /**
@@ -2643,16 +1940,7 @@
         * @return bool
         */
        public function isNamespaceProtected( User $user ) {
-               global $wgNamespaceProtection;
-
-               if ( isset( $wgNamespaceProtection[$this->mNamespace] ) ) {
-                       foreach ( 
(array)$wgNamespaceProtection[$this->mNamespace] as $right ) {
-                               if ( $right != '' && !$user->isAllowed( $right 
) ) {
-                                       return true;
-                               }
-                       }
-               }
-               return false;
+               return $this->getTitleSecurity()->isNamespaceProtected( $this, 
$user );
        }
 
        /**
@@ -2661,8 +1949,7 @@
         * @return bool If the page is subject to cascading restrictions.
         */
        public function isCascadeProtected() {
-               list( $sources, /* $restrictions */ ) = 
$this->getCascadeProtectionSources( false );
-               return ( $sources > 0 );
+               return $this->getTitleSecurity()->isCascadeProtected( $this );
        }
 
        /**
@@ -2675,7 +1962,7 @@
         * @since 1.23
         */
        public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
-               return $getPages ? $this->mCascadeSources !== null : 
$this->mHasCascadingRestrictions !== null;
+               return 
$this->getTitleSecurity()->areCascadeProtectionSourcesLoaded( $this, $getPages 
);
        }
 
        /**
@@ -2692,93 +1979,7 @@
         *        false.
         */
        public function getCascadeProtectionSources( $getPages = true ) {
-               global $wgContLang;
-               $pagerestrictions = array();
-
-               if ( $this->mCascadeSources !== null && $getPages ) {
-                       return array( $this->mCascadeSources, 
$this->mCascadingRestrictions );
-               } elseif ( $this->mHasCascadingRestrictions !== null && 
!$getPages ) {
-                       return array( $this->mHasCascadingRestrictions, 
$pagerestrictions );
-               }
-
-               wfProfileIn( __METHOD__ );
-
-               $dbr = wfGetDB( DB_SLAVE );
-
-               if ( $this->getNamespace() == NS_FILE ) {
-                       $tables = array( 'imagelinks', 'page_restrictions' );
-                       $where_clauses = array(
-                               'il_to' => $this->getDBkey(),
-                               'il_from=pr_page',
-                               'pr_cascade' => 1
-                       );
-               } else {
-                       $tables = array( 'templatelinks', 'page_restrictions' );
-                       $where_clauses = array(
-                               'tl_namespace' => $this->getNamespace(),
-                               'tl_title' => $this->getDBkey(),
-                               'tl_from=pr_page',
-                               'pr_cascade' => 1
-                       );
-               }
-
-               if ( $getPages ) {
-                       $cols = array( 'pr_page', 'page_namespace', 
'page_title',
-                               'pr_expiry', 'pr_type', 'pr_level' );
-                       $where_clauses[] = 'page_id=pr_page';
-                       $tables[] = 'page';
-               } else {
-                       $cols = array( 'pr_expiry' );
-               }
-
-               $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ 
);
-
-               $sources = $getPages ? array() : false;
-               $now = wfTimestampNow();
-               $purgeExpired = false;
-
-               foreach ( $res as $row ) {
-                       $expiry = $wgContLang->formatExpiry( $row->pr_expiry, 
TS_MW );
-                       if ( $expiry > $now ) {
-                               if ( $getPages ) {
-                                       $page_id = $row->pr_page;
-                                       $page_ns = $row->page_namespace;
-                                       $page_title = $row->page_title;
-                                       $sources[$page_id] = Title::makeTitle( 
$page_ns, $page_title );
-                                       # Add groups needed for each 
restriction type if its not already there
-                                       # Make sure this restriction type still 
exists
-
-                                       if ( !isset( 
$pagerestrictions[$row->pr_type] ) ) {
-                                               
$pagerestrictions[$row->pr_type] = array();
-                                       }
-
-                                       if (
-                                               isset( 
$pagerestrictions[$row->pr_type] )
-                                               && !in_array( $row->pr_level, 
$pagerestrictions[$row->pr_type] )
-                                       ) {
-                                               
$pagerestrictions[$row->pr_type][] = $row->pr_level;
-                                       }
-                               } else {
-                                       $sources = true;
-                               }
-                       } else {
-                               // Trigger lazy purge of expired restrictions 
from the db
-                               $purgeExpired = true;
-                       }
-               }
-               if ( $purgeExpired ) {
-                       Title::purgeExpiredRestrictions();
-               }
-
-               if ( $getPages ) {
-                       $this->mCascadeSources = $sources;
-                       $this->mCascadingRestrictions = $pagerestrictions;
-               } else {
-                       $this->mHasCascadingRestrictions = $sources;
-               }
-
-               wfProfileOut( __METHOD__ );
-               return array( $sources, $pagerestrictions );
+               return $this->getTitleSecurity()->getCascadeProtectionSources( 
$this, $getPages );
        }
 
        /**
@@ -2789,7 +1990,7 @@
         * @since 1.23
         */
        public function areRestrictionsLoaded() {
-               return $this->mRestrictionsLoaded;
+               return $this->getTitleSecurity()->newFromTitle( $this 
)->areRestrictionsLoaded( $this );
        }
 
        /**
@@ -2800,12 +2001,7 @@
         *     are required.
         */
        public function getRestrictions( $action ) {
-               if ( !$this->mRestrictionsLoaded ) {
-                       $this->loadRestrictions();
-               }
-               return isset( $this->mRestrictions[$action] )
-                               ? $this->mRestrictions[$action]
-                               : array();
+               return $this->getTitleSecurity()->newFromTitle( $this 
)->getRestrictions( $this, $action );
        }
 
        /**
@@ -2816,10 +2012,7 @@
         * @since 1.23
         */
        public function getAllRestrictions() {
-               if ( !$this->mRestrictionsLoaded ) {
-                       $this->loadRestrictions();
-               }
-               return $this->mRestrictions;
+               return $this->getTitleSecurity()->newFromTitle( $this 
)->getAllRestrictions( $this );
        }
 
        /**
@@ -2830,10 +2023,7 @@
         *     or not protected at all, or false if the action is not 
recognised.
         */
        public function getRestrictionExpiry( $action ) {
-               if ( !$this->mRestrictionsLoaded ) {
-                       $this->loadRestrictions();
-               }
-               return isset( $this->mRestrictionsExpiry[$action] ) ? 
$this->mRestrictionsExpiry[$action] : false;
+               return $this->getTitleSecurity()->getRestrictionExpiry( $this, 
$action );
        }
 
        /**
@@ -2842,28 +2032,7 @@
         * @return bool
         */
        function areRestrictionsCascading() {
-               if ( !$this->mRestrictionsLoaded ) {
-                       $this->loadRestrictions();
-               }
-
-               return $this->mCascadeRestriction;
-       }
-
-       /**
-        * Loads a string into mRestrictions array
-        *
-        * @param ResultWrapper $res Resource restrictions as an SQL result.
-        * @param string $oldFashionedRestrictions Comma-separated list of page
-        *        restrictions from page table (pre 1.10)
-        */
-       private function loadRestrictionsFromResultWrapper( $res, 
$oldFashionedRestrictions = null ) {
-               $rows = array();
-
-               foreach ( $res as $row ) {
-                       $rows[] = $row;
-               }
-
-               $this->loadRestrictionsFromRows( $rows, 
$oldFashionedRestrictions );
+               return $this->getTitleSecurity()->areRestrictionsCascading( 
$this );
        }
 
        /**
@@ -2876,80 +2045,7 @@
         *   restrictions from page table (pre 1.10)
         */
        public function loadRestrictionsFromRows( $rows, 
$oldFashionedRestrictions = null ) {
-               global $wgContLang;
-               $dbr = wfGetDB( DB_SLAVE );
-
-               $restrictionTypes = $this->getRestrictionTypes();
-
-               foreach ( $restrictionTypes as $type ) {
-                       $this->mRestrictions[$type] = array();
-                       $this->mRestrictionsExpiry[$type] = 
$wgContLang->formatExpiry( '', TS_MW );
-               }
-
-               $this->mCascadeRestriction = false;
-
-               # Backwards-compatibility: also load the restrictions from the 
page record (old format).
-
-               if ( $oldFashionedRestrictions === null ) {
-                       $oldFashionedRestrictions = $dbr->selectField( 'page', 
'page_restrictions',
-                               array( 'page_id' => $this->getArticleID() ), 
__METHOD__ );
-               }
-
-               if ( $oldFashionedRestrictions != '' ) {
-
-                       foreach ( explode( ':', trim( $oldFashionedRestrictions 
) ) as $restrict ) {
-                               $temp = explode( '=', trim( $restrict ) );
-                               if ( count( $temp ) == 1 ) {
-                                       // old old format should be treated as 
edit/move restriction
-                                       $this->mRestrictions['edit'] = explode( 
',', trim( $temp[0] ) );
-                                       $this->mRestrictions['move'] = explode( 
',', trim( $temp[0] ) );
-                               } else {
-                                       $restriction = trim( $temp[1] );
-                                       if ( $restriction != '' ) { //some old 
entries are empty
-                                               $this->mRestrictions[$temp[0]] 
= explode( ',', $restriction );
-                                       }
-                               }
-                       }
-
-                       $this->mOldRestrictions = true;
-
-               }
-
-               if ( count( $rows ) ) {
-                       # Current system - load second to make them override.
-                       $now = wfTimestampNow();
-                       $purgeExpired = false;
-
-                       # Cycle through all the restrictions.
-                       foreach ( $rows as $row ) {
-
-                               // Don't take care of restrictions types that 
aren't allowed
-                               if ( !in_array( $row->pr_type, 
$restrictionTypes ) ) {
-                                       continue;
-                               }
-
-                               // This code should be refactored, now that 
it's being used more generally,
-                               // But I don't really see any harm in leaving 
it in Block for now -werdna
-                               $expiry = $wgContLang->formatExpiry( 
$row->pr_expiry, TS_MW );
-
-                               // Only apply the restrictions if they haven't 
expired!
-                               if ( !$expiry || $expiry > $now ) {
-                                       
$this->mRestrictionsExpiry[$row->pr_type] = $expiry;
-                                       $this->mRestrictions[$row->pr_type] = 
explode( ',', trim( $row->pr_level ) );
-
-                                       $this->mCascadeRestriction |= 
$row->pr_cascade;
-                               } else {
-                                       // Trigger a lazy purge of expired 
restrictions
-                                       $purgeExpired = true;
-                               }
-                       }
-
-                       if ( $purgeExpired ) {
-                               Title::purgeExpiredRestrictions();
-                       }
-               }
-
-               $this->mRestrictionsLoaded = true;
+               $this->getTitleSecurity()->loadRestrictionsFromRows( $this, 
$rows, $oldFashionedRestrictions );
        }
 
        /**
@@ -2959,40 +2055,7 @@
         *   restrictions from page table (pre 1.10)
         */
        public function loadRestrictions( $oldFashionedRestrictions = null ) {
-               global $wgContLang;
-               if ( !$this->mRestrictionsLoaded ) {
-                       if ( $this->exists() ) {
-                               $dbr = wfGetDB( DB_SLAVE );
-
-                               $res = $dbr->select(
-                                       'page_restrictions',
-                                       array( 'pr_type', 'pr_expiry', 
'pr_level', 'pr_cascade' ),
-                                       array( 'pr_page' => 
$this->getArticleID() ),
-                                       __METHOD__
-                               );
-
-                               $this->loadRestrictionsFromResultWrapper( $res, 
$oldFashionedRestrictions );
-                       } else {
-                               $title_protection = $this->getTitleProtection();
-
-                               if ( $title_protection ) {
-                                       $now = wfTimestampNow();
-                                       $expiry = $wgContLang->formatExpiry( 
$title_protection['pt_expiry'], TS_MW );
-
-                                       if ( !$expiry || $expiry > $now ) {
-                                               // Apply the restrictions
-                                               
$this->mRestrictionsExpiry['create'] = $expiry;
-                                               $this->mRestrictions['create'] 
= explode( ',', trim( $title_protection['pt_create_perm'] ) );
-                                       } else { // Get rid of the old 
restrictions
-                                               
Title::purgeExpiredRestrictions();
-                                               $this->mTitleProtection = false;
-                                       }
-                               } else {
-                                       $this->mRestrictionsExpiry['create'] = 
$wgContLang->formatExpiry( '', TS_MW );
-                               }
-                               $this->mRestrictionsLoaded = true;
-                       }
-               }
+               $this->getTitleSecurity()->loadRestrictions( $this, 
$oldFashionedRestrictions );
        }
 
        /**
@@ -3000,32 +2063,14 @@
         * This is used when updating protection from 
WikiPage::doUpdateRestrictions().
         */
        public function flushRestrictions() {
-               $this->mRestrictionsLoaded = false;
-               $this->mTitleProtection = null;
+               $this->getTitleSecurity()->flushRestrictions( $this );
        }
 
        /**
         * Purge expired restrictions from the page_restrictions table
         */
-       static function purgeExpiredRestrictions() {
-               if ( wfReadOnly() ) {
-                       return;
-               }
-
-               $method = __METHOD__;
-               $dbw = wfGetDB( DB_MASTER );
-               $dbw->onTransactionIdle( function () use ( $dbw, $method ) {
-                       $dbw->delete(
-                               'page_restrictions',
-                               array( 'pr_expiry < ' . $dbw->addQuotes( 
$dbw->timestamp() ) ),
-                               $method
-                       );
-                       $dbw->delete(
-                               'protected_titles',
-                               array( 'pt_expiry < ' . $dbw->addQuotes( 
$dbw->timestamp() ) ),
-                               $method
-                       );
-               } );
+       public static function purgeExpiredRestrictions() {
+               $this->getTitleSecurity()->purgeExpiredRestrictions();
        }
 
        /**
@@ -3271,8 +2316,6 @@
                } else {
                        $this->mArticleID = intval( $newid );
                }
-               $this->mRestrictionsLoaded = false;
-               $this->mRestrictions = array();
                $this->mRedirect = null;
                $this->mLength = -1;
                $this->mLatestID = false;
@@ -4753,4 +3796,16 @@
                wfRunHooks( 'TitleGetEditNotices', array( $this, $oldid, 
&$notices ) );
                return $notices;
        }
+
+       /**
+        * Get the protection helper for this Title
+        *
+        * @return TitleSecurity
+        */
+       protected function getTitleSecurity() {
+               if ( !$this->mTitleSecurity ) {
+                       $this->mTitleSecurity = TitleSecurity::newFromTitle( 
$this );
+               }
+               return $this->mTitleSecurity;
+       }
 }
diff --git a/includes/security/TitleSecurity.php 
b/includes/security/TitleSecurity.php
new file mode 100644
index 0000000..b2d190c
--- /dev/null
+++ b/includes/security/TitleSecurity.php
@@ -0,0 +1,1217 @@
+<?php
+
+/**
+ * Encapsulates Title-based security logic
+ *
+ * @since 1.24
+ *
+ * TODO: resolve lazy-loading mess
+ */
+class TitleSecurity {
+       /** @var Title title to be protected */
+       protected $title;
+
+       /** @var array Array of groups allowed to edit this article */
+       protected $mRestrictions = array();
+
+       /** @var bool */
+       protected $mOldRestrictions = false;
+
+       /** @var bool Cascade restrictions on this page to included templates 
and images? */
+       protected $mCascadeRestriction;
+
+       /** Caching the results of getCascadeProtectionSources */
+       protected $mCascadingRestrictions;
+
+       /** @var array When do the restrictions on this page expire? */
+       protected $mRestrictionsExpiry = array();
+
+       /** @var bool Are cascading restrictions in effect on this page? */
+       protected $mHasCascadingRestrictions;
+
+       /** @var array Where are the cascading restrictions coming from on this 
page? */
+       protected $mCascadeSources;
+
+       /** @var bool Boolean for initialisation on demand */
+       protected $mRestrictionsLoaded = false;
+
+       /** @var mixed Cached value for getTitleProtection (create protection) 
*/
+       protected $mTitleProtection;
+
+       public static function newFromTitle( Title $title ) {
+               $p = new TitleSecurity();
+               $p->title = $title;
+               return $p;
+       }
+
+       /**
+        * Can $user perform $action on this page?
+        * This skips potentially expensive cascading permission checks
+        * as well as avoids expensive error formatting
+        *
+        * Suitable for use for nonessential UI controls in common cases, but
+        * _not_ for functional access control.
+        *
+        * May provide false positives, but should never provide a false 
negative.
+        *
+        * @param string $action Action that permission needs to be checked for
+        * @param User $user User to check; $wgUser will be used if not 
provided.
+        * @return bool
+        */
+       public function quickUserCan( $action, $user = null ) {
+               return $this->userCan( $action, $user, false );
+       }
+
+       /**
+        * Can $user perform $action on this page?
+        *
+        * @param string $action Action that permission needs to be checked for
+        * @param User $user User to check; $wgUser will be used if not
+        *   provided.
+        * @param bool $doExpensiveQueries Set this to false to avoid doing
+        *   unnecessary queries.
+        * @return bool
+        */
+       public function userCan( $action, $user = null, $doExpensiveQueries = 
true ) {
+               if ( !$user instanceof User ) {
+                       global $wgUser;
+                       $user = $wgUser;
+               }
+
+               return !count( self::getUserPermissionsErrorsInternals(
+                       $action, $user, $doExpensiveQueries, true ) );
+       }
+
+       /**
+        * Can $user perform $action on this page?
+        *
+        * @todo FIXME: This *does not* check throttles (User::pingLimiter()).
+        *
+        * @param string $action Action that permission needs to be checked for
+        * @param User $user User to check
+        * @param bool $doExpensiveQueries Set this to false to avoid doing 
unnecessary
+        *   queries by skipping checks for cascading protections and user 
blocks.
+        * @param array $ignoreErrors Array of Strings Set this to a list of 
message keys
+        *   whose corresponding errors may be ignored.
+        * @return array Array of arguments to wfMessage to explain permissions 
problems.
+        */
+       public function getUserPermissionsErrors( $action, $user, 
$doExpensiveQueries = true,
+               $ignoreErrors = array()
+       ) {
+               $errors = self::getUserPermissionsErrorsInternal( $action, 
$user, $doExpensiveQueries );
+
+               // Remove the errors being ignored.
+               foreach ( $errors as $index => $error ) {
+                       $error_key = is_array( $error ) ? $error[0] : $error;
+
+                       if ( in_array( $error_key, $ignoreErrors ) ) {
+                               unset( $errors[$index] );
+                       }
+               }
+
+               return $errors;
+       }
+
+       /**
+        * Permissions checks that fail most often, and which are easiest to 
test.
+        *
+        * @param string $action The action to check
+        * @param User $user User to check
+        * @param array $errors List of current errors
+        * @param bool $doExpensiveQueries Whether or not to perform expensive 
queries
+        * @param bool $short Short circuit on first error
+        *
+        * @return array List of errors
+        */
+       protected function checkQuickPermissions( $action, $user, $errors,
+               $doExpensiveQueries, $short
+       ) {
+               if ( !wfRunHooks( 'TitleQuickPermissions',
+                       array( $this->title, $user, $action, &$errors, 
$doExpensiveQueries, $short ) )
+               ) {
+                       return $errors;
+               }
+
+               if ( $action == 'create' ) {
+                       if (
+                               ( $this->title->isTalkPage() && 
!$user->isAllowed( 'createtalk' ) ) ||
+                               ( !$this->title->isTalkPage() && 
!$user->isAllowed( 'createpage' ) )
+                       ) {
+                               $errors[] = $user->isAnon() ? array( 
'nocreatetext' ) : array( 'nocreate-loggedin' );
+                       }
+               } elseif ( $action == 'move' ) {
+                       if ( !$user->isAllowed( 'move-rootuserpages' )
+                                       && $this->title->getNamespace() == 
NS_USER && !$this->title->isSubpage() ) {
+                               // Show user page-specific message only if the 
user can move other pages
+                               $errors[] = array( 'cant-move-user-page' );
+                       }
+
+                       // Check if user is allowed to move files if it's a file
+                       if ( $this->title->getNamespace() == NS_FILE && 
!$user->isAllowed( 'movefile' ) ) {
+                               $errors[] = array( 'movenotallowedfile' );
+                       }
+
+                       // Check if user is allowed to move category pages if 
it's a category page
+                       if ( $this->title->getNamespace() == NS_CATEGORY && 
!$user->isAllowed( 'move-categorypages' ) ) {
+                               $errors[] = array( 'cant-move-category-page' );
+                       }
+
+                       if ( !$user->isAllowed( 'move' ) ) {
+                               // User can't move anything
+                               $userCanMove = User::groupHasPermission( 
'user', 'move' );
+                               $autoconfirmedCanMove = 
User::groupHasPermission( 'autoconfirmed', 'move' );
+                               if ( $user->isAnon() && ( $userCanMove || 
$autoconfirmedCanMove ) ) {
+                                       // custom message if logged-in users 
without any special rights can move
+                                       $errors[] = array( 'movenologintext' );
+                               } else {
+                                       $errors[] = array( 'movenotallowed' );
+                               }
+                       }
+               } elseif ( $action == 'move-target' ) {
+                       if ( !$user->isAllowed( 'move' ) ) {
+                               // User can't move anything
+                               $errors[] = array( 'movenotallowed' );
+                       } elseif ( !$user->isAllowed( 'move-rootuserpages' )
+                                       && $this->title->getNamespace() == 
NS_USER && !$this->title->isSubpage() ) {
+                               // Show user page-specific message only if the 
user can move other pages
+                               $errors[] = array( 'cant-move-to-user-page' );
+                       } elseif ( !$user->isAllowed( 'move-categorypages' )
+                                       && $this->title->getNamespace() == 
NS_CATEGORY ) {
+                               // Show category page-specific message only if 
the user can move other pages
+                               $errors[] = array( 'cant-move-to-category-page' 
);
+                       }
+               } elseif ( !$user->isAllowed( $action ) ) {
+                       $errors[] = self::missingPermissionError( $action, 
$short );
+               }
+
+               return $errors;
+       }
+
+       /**
+        * Add the resulting error code to the errors array
+        *
+        * @param array $errors List of current errors
+        * @param array $result Result of errors
+        *
+        * @return array List of errors
+        */
+       protected function resultToError( $errors, $result ) {
+               if ( is_array( $result ) && count( $result ) && !is_array( 
$result[0] ) ) {
+                       // A single array representing an error
+                       $errors[] = $result;
+               } elseif ( is_array( $result ) && is_array( $result[0] ) ) {
+                       // A nested array representing multiple errors
+                       $errors = array_merge( $errors, $result );
+               } elseif ( $result !== '' && is_string( $result ) ) {
+                       // A string representing a message-id
+                       $errors[] = array( $result );
+               } elseif ( $result === false ) {
+                       // a generic "We don't want them to do that"
+                       $errors[] = array( 'badaccess-group0' );
+               }
+               return $errors;
+       }
+
+       /**
+        * Check various permission hooks
+        *
+        * @param string $action The action to check
+        * @param User $user User to check
+        * @param array $errors List of current errors
+        * @param bool $doExpensiveQueries Whether or not to perform expensive 
queries
+        * @param bool $short Short circuit on first error
+        *
+        * @return array List of errors
+        */
+       protected function checkPermissionHooks( $action, $user, $errors, 
$doExpensiveQueries, $short ) {
+               // Use getUserPermissionsErrors instead
+               $result = '';
+               if ( !wfRunHooks( 'userCan', array( &$this, &$user, $action, 
&$result ) ) ) {
+                       return $result ? array() : array( array( 
'badaccess-group0' ) );
+               }
+               // Check getUserPermissionsErrors hook
+               if ( !wfRunHooks( 'getUserPermissionsErrors', array( &$this, 
&$user, $action, &$result ) ) ) {
+                       $errors = self::resultToError( $errors, $result );
+               }
+               // Check getUserPermissionsErrorsExpensive hook
+               if (
+                       $doExpensiveQueries
+                       && !( $short && count( $errors ) > 0 )
+                       && !wfRunHooks( 'getUserPermissionsErrorsExpensive', 
array( &$this, &$user, $action, &$result ) )
+               ) {
+                       $errors = self::resultToError( $errors, $result );
+               }
+
+               return $errors;
+       }
+
+       /**
+        * Check permissions on special pages & namespaces
+        *
+        * @param string $action The action to check
+        * @param User $user User to check
+        * @param array $errors List of current errors
+        * @param bool $doExpensiveQueries Whether or not to perform expensive 
queries
+        * @param bool $short Short circuit on first error
+        *
+        * @return array List of errors
+        */
+       protected function checkSpecialsAndNSPermissions( $action, $user, 
$errors,
+               $doExpensiveQueries, $short
+       ) {
+               # Only 'createaccount' can be performed on special pages,
+               # which don't actually exist in the DB.
+               if ( NS_SPECIAL == $this->title->getNamespace() && $action !== 
'createaccount' ) {
+                       $errors[] = array( 'ns-specialprotected' );
+               }
+
+               # Check $wgNamespaceProtection for restricted namespaces
+               if ( self::isNamespaceProtected( $user ) ) {
+                       $ns = $this->title->getNamespace() == NS_MAIN ?
+                               wfMessage( 'nstab-main' )->text() : 
$this->title->getNsText();
+                       $errors[] = $this->title->getNamespace() == 
NS_MEDIAWIKI ?
+                               array( 'protectedinterface', $action ) : array( 
'namespaceprotected', $ns, $action );
+               }
+
+               return $errors;
+       }
+
+       /**
+        * Check CSS/JS sub-page permissions
+        *
+        * @param string $action The action to check
+        * @param User $user User to check
+        * @param array $errors List of current errors
+        * @param bool $doExpensiveQueries Whether or not to perform expensive 
queries
+        * @param bool $short Short circuit on first error
+        *
+        * @return array List of errors
+        */
+       protected function checkCSSandJSPermissions( $action, $user, $errors, 
$doExpensiveQueries, $short ) {
+               # Protect css/js subpages of user pages
+               # XXX: this might be better using restrictions
+               # XXX: right 'editusercssjs' is deprecated, for backward 
compatibility only
+               if ( $action != 'patrol' && !$user->isAllowed( 'editusercssjs' 
) ) {
+                       if ( preg_match( '/^' . preg_quote( $user->getName(), 
'/' ) . '\//', $this->title->getText() ) ) {
+                               if ( $this->title->isCssSubpage() && 
!$user->isAllowedAny( 'editmyusercss', 'editusercss' ) ) {
+                                       $errors[] = array( 
'mycustomcssprotected', $action );
+                               } elseif ( $this->title->isJsSubpage() && 
!$user->isAllowedAny( 'editmyuserjs', 'edituserjs' ) ) {
+                                       $errors[] = array( 
'mycustomjsprotected', $action );
+                               }
+                       } else {
+                               if ( $this->title->isCssSubpage() && 
!$user->isAllowed( 'editusercss' ) ) {
+                                       $errors[] = array( 
'customcssprotected', $action );
+                               } elseif ( $this->title->isJsSubpage() && 
!$user->isAllowed( 'edituserjs' ) ) {
+                                       $errors[] = array( 'customjsprotected', 
$action );
+                               }
+                       }
+               }
+
+               return $errors;
+       }
+
+       /**
+        * Check against page_restrictions table requirements on this
+        * page. The user must possess all required rights for this
+        * action.
+        *
+        * @param string $action The action to check
+        * @param User $user User to check
+        * @param array $errors List of current errors
+        * @param bool $doExpensiveQueries Whether or not to perform expensive 
queries
+        * @param bool $short Short circuit on first error
+        *
+        * @return array List of errors
+        */
+       protected function checkPageRestrictions( $action, $user, $errors, 
$doExpensiveQueries, $short ) {
+               foreach ( $this->getRestrictions( $action ) as $right ) {
+                       // Backwards compatibility, rewrite sysop -> 
editprotected
+                       if ( $right == 'sysop' ) {
+                               $right = 'editprotected';
+                       }
+                       // Backwards compatibility, rewrite autoconfirmed -> 
editsemiprotected
+                       if ( $right == 'autoconfirmed' ) {
+                               $right = 'editsemiprotected';
+                       }
+                       if ( $right == '' ) {
+                               continue;
+                       }
+                       if ( !$user->isAllowed( $right ) ) {
+                               $errors[] = array( 'protectedpagetext', $right, 
$action );
+                       } elseif ( $this->mCascadeRestriction && 
!$user->isAllowed( 'protect' ) ) {
+                               $errors[] = array( 'protectedpagetext', 
'protect', $action );
+                       }
+               }
+
+               return $errors;
+       }
+
+       /**
+        * Check restrictions on cascading pages.
+        *
+        * @param string $action The action to check
+        * @param User $user User to check
+        * @param array $errors List of current errors
+        * @param bool $doExpensiveQueries Whether or not to perform expensive 
queries
+        * @param bool $short Short circuit on first error
+        *
+        * @return array List of errors
+        */
+       protected function checkCascadingSourcesRestrictions( $action, $user, 
$errors,
+               $doExpensiveQueries, $short
+       ) {
+               if ( $doExpensiveQueries && !$this->title->isCssJsSubpage() ) {
+                       # We /could/ use the protection level on the source 
page, but it's
+                       # fairly ugly as we have to establish a precedence 
hierarchy for pages
+                       # included by multiple cascade-protected pages. So just 
restrict
+                       # it to people with 'protect' permission, as they could 
remove the
+                       # protection anyway.
+                       list( $cascadingSources, $restrictions ) = 
self::getCascadeProtectionSources();
+                       # Cascading protection depends on more than this page...
+                       # Several cascading protected pages may include this 
page...
+                       # Check each cascading level
+                       # This is only for protection restrictions, not for all 
actions
+                       if ( isset( $restrictions[$action] ) ) {
+                               foreach ( $restrictions[$action] as $right ) {
+                                       // Backwards compatibility, rewrite 
sysop -> editprotected
+                                       if ( $right == 'sysop' ) {
+                                               $right = 'editprotected';
+                                       }
+                                       // Backwards compatibility, rewrite 
autoconfirmed -> editsemiprotected
+                                       if ( $right == 'autoconfirmed' ) {
+                                               $right = 'editsemiprotected';
+                                       }
+                                       if ( $right != '' && 
!$user->isAllowedAll( 'protect', $right ) ) {
+                                               $pages = '';
+                                               foreach ( $cascadingSources as 
$page ) {
+                                                       $pages .= '* [[:' . 
$page->getPrefixedText() . "]]\n";
+                                               }
+                                               $errors[] = array( 
'cascadeprotected', count( $cascadingSources ), $pages, $action );
+                                       }
+                               }
+                       }
+               }
+
+               return $errors;
+       }
+
+       /**
+        * Check action permissions not already checked in checkQuickPermissions
+        *
+        * @param string $action The action to check
+        * @param User $user User to check
+        * @param array $errors List of current errors
+        * @param bool $doExpensiveQueries Whether or not to perform expensive 
queries
+        * @param bool $short Short circuit on first error
+        *
+        * @return array List of errors
+        */
+       protected function checkActionPermissions( $action, $user, $errors,
+               $doExpensiveQueries, $short
+       ) {
+               global $wgDeleteRevisionsLimit, $wgLang;
+
+               if ( $action == 'protect' ) {
+                       if ( count( self::getUserPermissionsErrorsInternal( 
'edit',
+                               $user, $doExpensiveQueries, true ) )
+                       ) {
+                               // If they can't edit, they shouldn't protect.
+                               $errors[] = array( 'protect-cantedit' );
+                       }
+               } elseif ( $action == 'create' ) {
+                       $title_protection = self::getTitleProtection();
+                       if ( $title_protection ) {
+                               if ( $title_protection['pt_create_perm'] == 
'sysop' ) {
+                                       $title_protection['pt_create_perm'] = 
'editprotected'; // B/C
+                               }
+                               if ( $title_protection['pt_create_perm'] == 
'autoconfirmed' ) {
+                                       $title_protection['pt_create_perm'] = 
'editsemiprotected'; // B/C
+                               }
+                               if ( $title_protection['pt_create_perm'] == ''
+                                       || !$user->isAllowed( 
$title_protection['pt_create_perm'] )
+                               ) {
+                                       $errors[] = array(
+                                               'titleprotected',
+                                               User::whoIs( 
$title_protection['pt_user'] ),
+                                               $title_protection['pt_reason']
+                                       );
+                               }
+                       }
+               } elseif ( $action == 'move' ) {
+                       // Check for immobile pages
+                       if ( !MWNamespace::isMovable( 
$this->title->getNamespace() ) ) {
+                               // Specific message for this case
+                               $errors[] = array( 'immobile-source-namespace', 
$this->title->getNsText() );
+                       } elseif ( !$this->title->isMovable() ) {
+                               // Less specific message for rarer cases
+                               $errors[] = array( 'immobile-source-page' );
+                       }
+               } elseif ( $action == 'move-target' ) {
+                       if ( !MWNamespace::isMovable( 
$this->title->getNamespace() ) ) {
+                               $errors[] = array( 'immobile-target-namespace', 
$this->title->getNsText() );
+                       } elseif ( !$this->title->isMovable() ) {
+                               $errors[] = array( 'immobile-target-page' );
+                       }
+               } elseif ( $action == 'delete' ) {
+                       $tempErrors = self::checkPageRestrictions( 'edit',
+                               $user, array(), $doExpensiveQueries, true );
+                       if ( !$tempErrors ) {
+                               $tempErrors = 
self::checkCascadingSourcesRestrictions( 'edit',
+                                       $user, $tempErrors, 
$doExpensiveQueries, true );
+                       }
+                       if ( $tempErrors ) {
+                               // If protection keeps them from editing, they 
shouldn't be able to delete.
+                               $errors[] = array( 'deleteprotected' );
+                       }
+                       if ( $doExpensiveQueries && $wgDeleteRevisionsLimit
+                               && !self::userCan( 'bigdelete', $user ) && 
$this->title->isBigDeletion()
+                       ) {
+                               $errors[] = array( 'delete-toobig', 
$wgLang->formatNum( $wgDeleteRevisionsLimit ) );
+                       }
+               }
+               return $errors;
+       }
+
+       /**
+        * Check that the user isn't blocked from editing.
+        *
+        * @param string $action The action to check
+        * @param User $user User to check
+        * @param array $errors List of current errors
+        * @param bool $doExpensiveQueries Whether or not to perform expensive 
queries
+        * @param bool $short Short circuit on first error
+        *
+        * @return array List of errors
+        */
+       protected function checkUserBlock( $action, $user, $errors, 
$doExpensiveQueries, $short ) {
+               // Account creation blocks handled at userlogin.
+               // Unblocking handled in SpecialUnblock
+               if ( !$doExpensiveQueries || in_array( $action, array( 
'createaccount', 'unblock' ) ) ) {
+                       return $errors;
+               }
+
+               global $wgEmailConfirmToEdit;
+
+               if ( $wgEmailConfirmToEdit && !$user->isEmailConfirmed() ) {
+                       $errors[] = array( 'confirmedittext' );
+               }
+
+               if ( ( $action == 'edit' || $action == 'create' ) && 
!$user->isBlockedFrom( $this->title ) ) {
+                       // Don't block the user from editing their own talk 
page unless they've been
+                       // explicitly blocked from that too.
+               } elseif ( $user->isBlocked() && $user->mBlock->prevents( 
$action ) !== false ) {
+                       // @todo FIXME: Pass the relevant context into this 
function.
+                       $errors[] = $user->getBlock()->getPermissionsError( 
RequestContext::getMain() );
+               }
+
+               return $errors;
+       }
+
+       /**
+        * Check that the user is allowed to read this page.
+        *
+        * @param string $action The action to check
+        * @param User $user User to check
+        * @param array $errors List of current errors
+        * @param bool $doExpensiveQueries Whether or not to perform expensive 
queries
+        * @param bool $short Short circuit on first error
+        *
+        * @return array List of errors
+        */
+       protected function checkReadPermissions( $action, $user, $errors, 
$doExpensiveQueries, $short ) {
+               global $wgWhitelistRead, $wgWhitelistReadRegexp;
+
+               $whitelisted = false;
+               if ( User::isEveryoneAllowed( 'read' ) ) {
+                       # Shortcut for public wikis, allows skipping quite a 
bit of code
+                       $whitelisted = true;
+               } elseif ( $user->isAllowed( 'read' ) ) {
+                       # If the user is allowed to read pages, he is allowed 
to read all pages
+                       $whitelisted = true;
+               } elseif ( $this->title->isSpecial( 'Userlogin' )
+                       || $this->title->isSpecial( 'ChangePassword' )
+                       || $this->title->isSpecial( 'PasswordReset' )
+               ) {
+                       # Always grant access to the login page.
+                       # Even anons need to be able to log in.
+                       $whitelisted = true;
+               } elseif ( is_array( $wgWhitelistRead ) && count( 
$wgWhitelistRead ) ) {
+                       # Time to check the whitelist
+                       # Only do these checks is there's something to check 
against
+                       $name = $this->title->getPrefixedText();
+                       $dbName = $this->title->getPrefixedDBkey();
+
+                       // Check for explicit whitelisting with and without 
underscores
+                       if ( in_array( $name, $wgWhitelistRead, true ) || 
in_array( $dbName, $wgWhitelistRead, true ) ) {
+                               $whitelisted = true;
+                       } elseif ( $this->title->getNamespace() == NS_MAIN ) {
+                               # Old settings might have the title prefixed 
with
+                               # a colon for main-namespace pages
+                               if ( in_array( ':' . $name, $wgWhitelistRead ) 
) {
+                                       $whitelisted = true;
+                               }
+                       } elseif ( $this->title->isSpecialPage() ) {
+                               # If it's a special page, ditch the subpage bit 
and check again
+                               $name = $this->title->getDBkey();
+                               list( $name, /* $subpage */ ) = 
SpecialPageFactory::resolveAlias( $name );
+                               if ( $name ) {
+                                       $pure = SpecialPage::getTitleFor( $name 
)->getPrefixedText();
+                                       if ( in_array( $pure, $wgWhitelistRead, 
true ) ) {
+                                               $whitelisted = true;
+                                       }
+                               }
+                       }
+               }
+
+               if ( !$whitelisted && is_array( $wgWhitelistReadRegexp ) && 
!empty( $wgWhitelistReadRegexp ) ) {
+                       $name = $this->title->getPrefixedText();
+                       // Check for regex whitelisting
+                       foreach ( $wgWhitelistReadRegexp as $listItem ) {
+                               if ( preg_match( $listItem, $name ) ) {
+                                       $whitelisted = true;
+                                       break;
+                               }
+                       }
+               }
+
+               if ( !$whitelisted ) {
+                       # If the title is not whitelisted, give extensions a 
chance to do so...
+                       wfRunHooks( 'TitleReadWhitelist', array( $this->title, 
$user, &$whitelisted ) );
+                       if ( !$whitelisted ) {
+                               $errors[] = self::missingPermissionError( 
$action, $short );
+                       }
+               }
+
+               return $errors;
+       }
+
+       /**
+        * Get a description array when the user doesn't have the right to 
perform
+        * $action (i.e. when User::isAllowed() returns false)
+        *
+        * @param string $action The action to check
+        * @param bool $short Short circuit on first error
+        * @return array List of errors
+        */
+       protected function missingPermissionError( $action, $short ) {
+               // We avoid expensive display logic for quickUserCan's and such
+               if ( $short ) {
+                       return array( 'badaccess-group0' );
+               }
+
+               $groups = array_map( array( 'User', 'makeGroupLinkWiki' ),
+                       User::getGroupsWithPermission( $action ) );
+
+               if ( count( $groups ) ) {
+                       global $wgLang;
+                       return array(
+                               'badaccess-groups',
+                               $wgLang->commaList( $groups ),
+                               count( $groups )
+                       );
+               } else {
+                       return array( 'badaccess-group0' );
+               }
+       }
+
+       /**
+        * Can $user perform $action on this page? This is an internal function,
+        * which checks ONLY that previously checked by userCan (i.e. it leaves 
out
+        * checks on wfReadOnly() and blocks)
+        *
+        * @param string $action Action that permission needs to be checked for
+        * @param User $user User to check
+        * @param bool $doExpensiveQueries Set this to false to avoid doing 
unnecessary queries.
+        * @param bool $short Set this to true to stop after the first 
permission error.
+        * @return array Array of arrays of the arguments to wfMessage to 
explain permissions problems.
+        */
+       protected function getUserPermissionsErrorsInternal( $action, $user,
+               $doExpensiveQueries = true, $short = false
+       ) {
+               wfProfileIn( __METHOD__ );
+
+               # Read has special handling
+               if ( $action == 'read' ) {
+                       $checks = array(
+                               'checkPermissionHooks',
+                               'checkReadPermissions',
+                       );
+               # Don't call checkSpecialsAndNSPermissions or 
checkCSSandJSPermissions
+               # here as it will lead to duplicate error messages. This is 
okay to do
+               # since anywhere that checks for create will also check for 
edit, and
+               # those checks are called for edit.
+               } elseif ( $action == 'create' ) {
+                       $checks = array(
+                               'checkQuickPermissions',
+                               'checkPermissionHooks',
+                               'checkPageRestrictions',
+                               'checkCascadingSourcesRestrictions',
+                               'checkActionPermissions',
+                               'checkUserBlock'
+                       );
+               } else {
+                       $checks = array(
+                               'checkQuickPermissions',
+                               'checkPermissionHooks',
+                               'checkSpecialsAndNSPermissions',
+                               'checkCSSandJSPermissions',
+                               'checkPageRestrictions',
+                               'checkCascadingSourcesRestrictions',
+                               'checkActionPermissions',
+                               'checkUserBlock'
+                       );
+               }
+
+               $errors = array();
+               while ( count( $checks ) > 0 &&
+                               !( $short && count( $errors ) > 0 ) ) {
+                       $method = array_shift( $checks );
+                       $errors = $this->$method( $action, $user, $errors, 
$doExpensiveQueries, $short );
+               }
+
+               wfProfileOut( __METHOD__ );
+               return $errors;
+       }
+
+       /**
+        * Get a filtered list of all restriction types supported by this wiki.
+        * @param bool $exists True to get all restriction types that apply to
+        * titles that do exist, False for all restriction types that apply to
+        * titles that do not exist
+        * @return array
+        */
+       public static function getFilteredRestrictionTypes( $exists = true ) {
+               global $wgRestrictionTypes;
+               $types = $wgRestrictionTypes;
+               if ( $exists ) {
+                       # Remove the create restriction for existing titles
+                       $types = array_diff( $types, array( 'create' ) );
+               } else {
+                       # Only the create and upload restrictions apply to 
non-existing titles
+                       $types = array_intersect( $types, array( 'create', 
'upload' ) );
+               }
+               return $types;
+       }
+
+       /**
+        * Returns restriction types for the current Title
+        *
+        * @return array Applicable restriction types
+        */
+       public function getRestrictionTypes() {
+               if ( $this->title->isSpecialPage() ) {
+                       return array();
+               }
+
+               $types = self::getFilteredRestrictionTypes( 
$this->title->exists() );
+
+               if ( $this->title->getNamespace() != NS_FILE ) {
+                       # Remove the upload restriction for non-file titles
+                       $types = array_diff( $types, array( 'upload' ) );
+               }
+
+               wfRunHooks( 'TitleGetRestrictionTypes', array( $title, &$types 
) );
+
+               wfDebug( __METHOD__ . ': applicable restrictions to [[' .
+                       $this->title->getPrefixedText() . ']] are {' . implode( 
',', $types ) . "}\n" );
+
+               return $types;
+       }
+
+       /**
+        * Is this title subject to title protection?
+        * Title protection is the one applied against creation of such title.
+        *
+        * @return array|bool An associative array representing any existent 
title
+        *   protection, or false if there's none.
+        */
+       protected function getTitleProtection() {
+               // Can't protect pages in special namespaces
+               if ( $this->title->getNamespace() < 0 ) {
+                       return false;
+               }
+
+               // Can't protect pages that exist.
+               if ( $this->title->exists() ) {
+                       return false;
+               }
+
+               if ( $this->mTitleProtection === null ) {
+                       $dbr = wfGetDB( DB_SLAVE );
+                       $res = $dbr->select(
+                               'protected_titles',
+                               array( 'pt_user', 'pt_reason', 'pt_expiry', 
'pt_create_perm' ),
+                               array( 'pt_namespace' => 
$this->title->getNamespace(), 'pt_title' => $this->title->getDBkey() ),
+                               __METHOD__
+                       );
+
+                       // fetchRow returns false if there are no rows.
+                       $this->mTitleProtection = $dbr->fetchRow( $res );
+               }
+               return $this->mTitleProtection;
+       }
+
+       /**
+        * Remove any title protection due to page existing
+        */
+       protected function deleteTitleProtection() {
+               $dbw = wfGetDB( DB_MASTER );
+
+               $dbw->delete(
+                       'protected_titles',
+                       array( 'pt_namespace' => $this->title->getNamespace(), 
'pt_title' => $this->title->getDBkey() ),
+                       __METHOD__
+               );
+               $this->mTitleProtection = false;
+       }
+
+       /**
+        * Is this page "semi-protected" - the *only* protection levels are 
listed
+        * in $wgSemiprotectedRestrictionLevels?
+        *
+        * @param string $action Action to check (default: edit)
+        * @return bool
+        */
+       public function isSemiProtected( $action = 'edit' ) {
+               global $wgSemiprotectedRestrictionLevels;
+
+               $restrictions = $this->getRestrictions( $action );
+               $semi = $wgSemiprotectedRestrictionLevels;
+               if ( !$restrictions || !$semi ) {
+                       // Not protected, or all protection is full protection
+                       return false;
+               }
+
+               // Remap autoconfirmed to editsemiprotected for BC
+               foreach ( array_keys( $semi, 'autoconfirmed' ) as $key ) {
+                       $semi[$key] = 'editsemiprotected';
+               }
+               foreach ( array_keys( $restrictions, 'autoconfirmed' ) as $key 
) {
+                       $restrictions[$key] = 'editsemiprotected';
+               }
+
+               return !array_diff( $restrictions, $semi );
+       }
+
+       /**
+        * Does the title correspond to a protected article?
+        *
+        * @param string $action The action the page is protected from,
+        * by default checks all actions.
+        * @return bool
+        */
+       public function isProtected( $action = '' ) {
+               global $wgRestrictionLevels;
+
+               $restrictionTypes = $this->getRestrictionTypes();
+
+               # Special pages have inherent protection
+               if ( $this->title->isSpecialPage() ) {
+                       return true;
+               }
+
+               # Check regular protection levels
+               foreach ( $restrictionTypes as $type ) {
+                       if ( $action == $type || $action == '' ) {
+                               $r = $this->getRestrictions( $type );
+                               foreach ( $wgRestrictionLevels as $level ) {
+                                       if ( in_array( $level, $r ) && $level 
!= '' ) {
+                                               return true;
+                                       }
+                               }
+                       }
+               }
+
+               return false;
+       }
+
+       /**
+        * Determines if $user is unable to edit this page because it has been 
protected
+        * by $wgNamespaceProtection.
+        *
+        * @param User $user User object to check permissions
+        * @return bool
+        */
+       public function isNamespaceProtected( User $user ) {
+               global $wgNamespaceProtection;
+
+               if ( isset( 
$wgNamespaceProtection[$this->title->getNamespace()] ) ) {
+                       foreach ( 
(array)$wgNamespaceProtection[$this->title->getNamespace()] as $right ) {
+                               if ( $right != '' && !$user->isAllowed( $right 
) ) {
+                                       return true;
+                               }
+                       }
+               }
+               return false;
+       }
+
+       /**
+        * Cascading protection: Return true if cascading restrictions apply to 
this page, false if not.
+        *
+        * @return bool If the page is subject to cascading restrictions.
+        */
+       public function isCascadeProtected() {
+               list( $sources, /* $restrictions */ ) = 
$this->getCascadeProtectionSources( false );
+               return ( $sources > 0 );
+       }
+
+       /**
+        * Determines whether cascading protection sources have already been 
loaded from
+        * the database.
+        *
+        * @param bool $getPages True to check if the pages are loaded, or 
false to check
+        * if the status is loaded.
+        * @return bool Whether or not the specified information has been loaded
+        */
+       public function areCascadeProtectionSourcesLoaded( $getPages = true ) {
+               return $getPages ? $this->mCascadeSources !== null : 
$this->mHasCascadingRestrictions !== null;
+       }
+
+       /**
+        * Cascading protection: Get the source of any cascading restrictions 
on this page.
+        *
+        * @param bool $getPages Whether or not to retrieve the actual pages
+        *        that the restrictions have come from and the actual 
restrictions
+        *        themselves.
+        * @return array Two elements: First is an array of Title objects of the
+        *        pages from which cascading restrictions have come, false for
+        *        none, or true if such restrictions exist but $getPages was not
+        *        set. Second is an array like that returned by
+        *        TitleSecurity::getAllRestrictions(), or an empty array if 
$getPages is
+        *        false.
+        */
+       public function getCascadeProtectionSources( $getPages = true ) {
+               global $wgContLang;
+               $pagerestrictions = array();
+
+               if ( $this->mCascadeSources !== null && $getPages ) {
+                       return array( $this->mCascadeSources, 
$this->mCascadingRestrictions );
+               } elseif ( $this->mHasCascadingRestrictions !== null && 
!$getPages ) {
+                       return array( $this->mHasCascadingRestrictions, 
$pagerestrictions );
+               }
+
+               wfProfileIn( __METHOD__ );
+
+               $dbr = wfGetDB( DB_SLAVE );
+
+               if ( $this->title->getNamespace() == NS_FILE ) {
+                       $tables = array( 'imagelinks', 'page_restrictions' );
+                       $where_clauses = array(
+                               'il_to' => $this->title->getDBkey(),
+                               'il_from=pr_page',
+                               'pr_cascade' => 1
+                       );
+               } else {
+                       $tables = array( 'templatelinks', 'page_restrictions' );
+                       $where_clauses = array(
+                               'tl_namespace' => $this->title->getNamespace(),
+                               'tl_title' => $this->title->getDBkey(),
+                               'tl_from=pr_page',
+                               'pr_cascade' => 1
+                       );
+               }
+
+               if ( $getPages ) {
+                       $cols = array( 'pr_page', 'page_namespace', 
'page_title',
+                               'pr_expiry', 'pr_type', 'pr_level' );
+                       $where_clauses[] = 'page_id=pr_page';
+                       $tables[] = 'page';
+               } else {
+                       $cols = array( 'pr_expiry' );
+               }
+
+               $res = $dbr->select( $tables, $cols, $where_clauses, __METHOD__ 
);
+
+               $sources = $getPages ? array() : false;
+               $now = wfTimestampNow();
+               $purgeExpired = false;
+
+               foreach ( $res as $row ) {
+                       $expiry = $wgContLang->formatExpiry( $row->pr_expiry, 
TS_MW );
+                       if ( $expiry > $now ) {
+                               if ( $getPages ) {
+                                       $page_id = $row->pr_page;
+                                       $page_ns = $row->page_namespace;
+                                       $page_title = $row->page_title;
+                                       $sources[$page_id] = Title::makeTitle( 
$page_ns, $page_title );
+                                       # Add groups needed for each 
restriction type if its not already there
+                                       # Make sure this restriction type still 
exists
+
+                                       if ( !isset( 
$pagerestrictions[$row->pr_type] ) ) {
+                                               
$pagerestrictions[$row->pr_type] = array();
+                                       }
+
+                                       if (
+                                               isset( 
$pagerestrictions[$row->pr_type] )
+                                               && !in_array( $row->pr_level, 
$pagerestrictions[$row->pr_type] )
+                                       ) {
+                                               
$pagerestrictions[$row->pr_type][] = $row->pr_level;
+                                       }
+                               } else {
+                                       $sources = true;
+                               }
+                       } else {
+                               // Trigger lazy purge of expired restrictions 
from the db
+                               $purgeExpired = true;
+                       }
+               }
+               if ( $purgeExpired ) {
+                       TitleSecurity::purgeExpiredRestrictions();
+               }
+
+               if ( $getPages ) {
+                       $this->mCascadeSources = $sources;
+                       $this->mCascadingRestrictions = $pagerestrictions;
+               } else {
+                       $this->mHasCascadingRestrictions = $sources;
+               }
+
+               wfProfileOut( __METHOD__ );
+               return array( $sources, $pagerestrictions );
+       }
+
+       /**
+        * Accessor for mRestrictionsLoaded
+        *
+        * @return bool Whether or not the page's restrictions have already been
+        * loaded from the database
+        */
+       public function areRestrictionsLoaded() {
+               return $this->mRestrictionsLoaded;
+       }
+
+       /**
+        * Accessor/initialisation for mRestrictions
+        *
+        * @param string $action Action that permission needs to be checked for
+        * @return array Restriction levels needed to take the action. All 
levels
+        *     are required.
+        */
+       public function getRestrictions( $action ) {
+               if ( !$this->mRestrictionsLoaded ) {
+                       $this->loadRestrictions();
+               }
+               return isset( $this->mRestrictions[$action] )
+                               ? $this->mRestrictions[$action]
+                               : array();
+       }
+
+       /**
+        * Accessor/initialisation for mRestrictions
+        *
+        * @return array Keys are actions, values are arrays as returned by
+        *     TitleSecurity::getRestrictions()
+        */
+       public function getAllRestrictions() {
+               if ( !$this->mRestrictionsLoaded ) {
+                       $this->loadRestrictions();
+               }
+               return $this->mRestrictions;
+       }
+
+       /**
+        * Get the expiry time for the restriction against a given action
+        *
+        * @param string $action
+        * @return string|bool 14-char timestamp, or 'infinity' if the page is 
protected forever
+        *     or not protected at all, or false if the action is not 
recognised.
+        */
+       public function getRestrictionExpiry( $action ) {
+               if ( !$this->mRestrictionsLoaded ) {
+                       $this->loadRestrictions();
+               }
+               return isset( $this->mRestrictionsExpiry[$action] ) ? 
$this->mRestrictionsExpiry[$action] : false;
+       }
+
+       /**
+        * Returns cascading restrictions for the current article
+        *
+        * @return bool
+        */
+       public function areRestrictionsCascading() {
+               if ( !$this->mRestrictionsLoaded ) {
+                       $this->loadRestrictions();
+               }
+
+               return $this->mCascadeRestriction;
+       }
+
+       /**
+        * Loads a string into mRestrictions array
+        *
+        * @param ResultWrapper $res Resource restrictions as an SQL result.
+        * @param string $oldFashionedRestrictions Comma-separated list of page
+        *        restrictions from page table (pre 1.10)
+        */
+       protected function loadRestrictionsFromResultWrapper( $res, 
$oldFashionedRestrictions = null ) {
+               $rows = array();
+
+               foreach ( $res as $row ) {
+                       $rows[] = $row;
+               }
+
+               $this->loadRestrictionsFromRows( $rows, 
$oldFashionedRestrictions );
+       }
+
+       /**
+        * Compiles list of active page restrictions from both page table (pre 
1.10)
+        * and page_restrictions table for this existing page.
+        * Public for usage by LiquidThreads.
+        *
+        * @param array $rows Array of db result objects
+        * @param string $oldFashionedRestrictions Comma-separated list of page
+        *   restrictions from page table (pre 1.10)
+        */
+       public function loadRestrictionsFromRows( $rows, 
$oldFashionedRestrictions = null ) {
+               global $wgContLang;
+               $dbr = wfGetDB( DB_SLAVE );
+
+               $restrictionTypes = $this->getRestrictionTypes();
+
+               foreach ( $restrictionTypes as $type ) {
+                       $this->mRestrictions[$type] = array();
+                       $this->mRestrictionsExpiry[$type] = 
$wgContLang->formatExpiry( '', TS_MW );
+               }
+
+               $this->mCascadeRestriction = false;
+
+               # Backwards-compatibility: also load the restrictions from the 
page record (old format).
+
+               if ( $oldFashionedRestrictions === null ) {
+                       $oldFashionedRestrictions = $dbr->selectField( 'page', 
'page_restrictions',
+                               array( 'page_id' => 
$this->title->getArticleID() ), __METHOD__ );
+               }
+
+               if ( $oldFashionedRestrictions != '' ) {
+
+                       foreach ( explode( ':', trim( $oldFashionedRestrictions 
) ) as $restrict ) {
+                               $temp = explode( '=', trim( $restrict ) );
+                               if ( count( $temp ) == 1 ) {
+                                       // old old format should be treated as 
edit/move restriction
+                                       $this->mRestrictions['edit'] = explode( 
',', trim( $temp[0] ) );
+                                       $this->mRestrictions['move'] = explode( 
',', trim( $temp[0] ) );
+                               } else {
+                                       $restriction = trim( $temp[1] );
+                                       if ( $restriction != '' ) { //some old 
entries are empty
+                                               $this->mRestrictions[$temp[0]] 
= explode( ',', $restriction );
+                                       }
+                               }
+                       }
+
+                       $this->mOldRestrictions = true;
+
+               }
+
+               if ( count( $rows ) ) {
+                       # Current system - load second to make them override.
+                       $now = wfTimestampNow();
+                       $purgeExpired = false;
+
+                       # Cycle through all the restrictions.
+                       foreach ( $rows as $row ) {
+
+                               // Don't take care of restrictions types that 
aren't allowed
+                               if ( !in_array( $row->pr_type, 
$restrictionTypes ) ) {
+                                       continue;
+                               }
+
+                               // This code should be refactored, now that 
it's being used more generally,
+                               // But I don't really see any harm in leaving 
it in Block for now -werdna
+                               $expiry = $wgContLang->formatExpiry( 
$row->pr_expiry, TS_MW );
+
+                               // Only apply the restrictions if they haven't 
expired!
+                               if ( !$expiry || $expiry > $now ) {
+                                       
$this->mRestrictionsExpiry[$row->pr_type] = $expiry;
+                                       $this->mRestrictions[$row->pr_type] = 
explode( ',', trim( $row->pr_level ) );
+
+                                       $this->mCascadeRestriction |= 
$row->pr_cascade;
+                               } else {
+                                       // Trigger a lazy purge of expired 
restrictions
+                                       $purgeExpired = true;
+                               }
+                       }
+
+                       if ( $purgeExpired ) {
+                               TitleSecurity::purgeExpiredRestrictions();
+                       }
+               }
+
+               $this->mRestrictionsLoaded = true;
+       }
+
+       /**
+        * Load restrictions from the page_restrictions table
+        *
+        * @param string $oldFashionedRestrictions Comma-separated list of page
+        *   restrictions from page table (pre 1.10)
+        */
+       public function loadRestrictions( $oldFashionedRestrictions = null ) {
+               global $wgContLang;
+               if ( !$this->mRestrictionsLoaded ) {
+                       if ( $this->title->exists() ) {
+                               $dbr = wfGetDB( DB_SLAVE );
+
+                               $res = $dbr->select(
+                                       'page_restrictions',
+                                       array( 'pr_type', 'pr_expiry', 
'pr_level', 'pr_cascade' ),
+                                       array( 'pr_page' => 
$this->title->getArticleID() ),
+                                       __METHOD__
+                               );
+
+                               $this->loadRestrictionsFromResultWrapper( $res, 
$oldFashionedRestrictions );
+                       } else {
+                               $title_protection = $this->getTitleProtection();
+
+                               if ( $title_protection ) {
+                                       $now = wfTimestampNow();
+                                       $expiry = $wgContLang->formatExpiry( 
$title_protection['pt_expiry'], TS_MW );
+
+                                       if ( !$expiry || $expiry > $now ) {
+                                               // Apply the restrictions
+                                               
$this->mRestrictionsExpiry['create'] = $expiry;
+                                               $this->mRestrictions['create'] 
= explode( ',', trim( $title_protection['pt_create_perm'] ) );
+                                       } else { // Get rid of the old 
restrictions
+                                               
TitleSecurity::purgeExpiredRestrictions();
+                                               $this->mTitleProtection = false;
+                                       }
+                               } else {
+                                       $this->mRestrictionsExpiry['create'] = 
$wgContLang->formatExpiry( '', TS_MW );
+                               }
+                               $this->mRestrictionsLoaded = true;
+                       }
+               }
+       }
+
+       /**
+        * Flush the protection cache in this object and force reload from the 
database.
+        * This is used when updating protection from 
WikiPage::doUpdateRestrictions().
+        */
+       public function flushRestrictions() {
+               $this->mRestrictionsLoaded = false;
+               $this->mTitleProtection = null;
+       }
+
+       /**
+        * Purge expired restrictions from the page_restrictions table
+        */
+       public static function purgeExpiredRestrictions() {
+               if ( wfReadOnly() ) {
+                       return;
+               }
+
+               $method = __METHOD__;
+               $dbw = wfGetDB( DB_MASTER );
+               $dbw->onTransactionIdle( function () use ( $dbw, $method ) {
+                       $dbw->delete(
+                               'page_restrictions',
+                               array( 'pr_expiry < ' . $dbw->addQuotes( 
$dbw->timestamp() ) ),
+                               $method
+                       );
+                       $dbw->delete(
+                               'protected_titles',
+                               array( 'pt_expiry < ' . $dbw->addQuotes( 
$dbw->timestamp() ) ),
+                               $method
+                       );
+               } );
+       }
+}

-- 
To view, visit https://gerrit.wikimedia.org/r/166357
To unsubscribe, visit https://gerrit.wikimedia.org/r/settings

Gerrit-MessageType: newchange
Gerrit-Change-Id: Ifa5671f5e4cf16cf5447bf132b5081af95e543ee
Gerrit-PatchSet: 1
Gerrit-Project: mediawiki/core
Gerrit-Branch: master
Gerrit-Owner: Awight <[email protected]>

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