Fix an issue where internal paging of notifications could fail if some notifications are not visible

Summary:
Ref T13266. See <https://discourse.phabricator-community.org/t/notification-page-throws-unrecoverable-fatal-error/2651/>.

The "notifications" query currently uses offset paging for no apparent reason (just a legacy issue?), so some of the paging code is only reachable internally.

  - Stop it from using offset paging, since modern cursor paging is fine here (and Feed has used cursor paging for a long time).
  - Fix the non-offset paging to work like Feed.

Also:

  - Remove a couple of stub methods with no callsites after cursor refactoring.

Test Plan:
  - Set things up so I had more than 100 notifications and some in the first 100 were policy filtered, to reproduce the issue (I just made `FeedStory` return `NO_ONE` as a visibility policy).
  - Applied the patch, notifications now page cleanly.
  - Verified that "Next Page" took me to the right place in the result list.

Reviewers: amckinley

Reviewed By: amckinley

Subscribers: hskiba

Maniphest Tasks: T13266

Differential Revision: https://secure.phabricator.com/D20455

src/applications/meta/query/PhabricatorApplicationQuery.php

@@ -170,10 +170,4 @@ final class PhabricatorApplicationQuery
     return null;
   }
 
-  protected function getResultCursor($object) {
-    // TODO: This won't work, but doesn't matter until we write more than 100
-    // applications. Since we only have about 70, just avoid fataling for now.
-    return null;
-  }
-
 }

src/applications/notification/query/PhabricatorNotificationQuery.php

@@ -53,10 +53,10 @@ final class PhabricatorNotificationQuery
 
     $data = queryfx_all(
       $conn,
-      'SELECT story.*, notif.hasViewed FROM %R notif
+      'SELECT story.*, notification.hasViewed FROM %R notification
-         JOIN %R story ON notif.chronologicalKey = story.chronologicalKey
+         JOIN %R story ON notification.chronologicalKey = story.chronologicalKey
          %Q
-         ORDER BY notif.chronologicalKey DESC
+         ORDER BY notification.chronologicalKey DESC
          %Q',
       $notification_table,
       $story_table,
@@ -82,21 +82,21 @@ final class PhabricatorNotificationQuery
     if ($this->userPHIDs !== null) {
       $where[] = qsprintf(
         $conn,
-        'notif.userPHID IN (%Ls)',
+        'notification.userPHID IN (%Ls)',
         $this->userPHIDs);
     }
 
     if ($this->unread !== null) {
       $where[] = qsprintf(
         $conn,
-        'notif.hasViewed = %d',
+        'notification.hasViewed = %d',
         (int)!$this->unread);
     }
 
     if ($this->keys !== null) {
       $where[] = qsprintf(
         $conn,
-        'notif.chronologicalKey IN (%Ls)',
+        'notification.chronologicalKey IN (%Ls)',
         $this->keys);
     }
 
@@ -113,8 +113,53 @@ final class PhabricatorNotificationQuery
     return $stories;
   }
 
-  protected function getResultCursor($item) {
+  protected function getDefaultOrderVector() {
-    return $item->getChronologicalKey();
+    return array('key');
+  }
+
+  public function getBuiltinOrders() {
+    return array(
+      'newest' => array(
+        'vector' => array('key'),
+        'name' => pht('Creation (Newest First)'),
+        'aliases' => array('created'),
+      ),
+      'oldest' => array(
+        'vector' => array('-key'),
+        'name' => pht('Creation (Oldest First)'),
+      ),
+    );
+  }
+
+  public function getOrderableColumns() {
+    return array(
+      'key' => array(
+        'table' => 'notification',
+        'column' => 'chronologicalKey',
+        'type' => 'string',
+        'unique' => true,
+      ),
+    );
+  }
+
+  protected function applyExternalCursorConstraintsToQuery(
+    PhabricatorCursorPagedPolicyAwareQuery $subquery,
+    $cursor) {
+    $subquery->withKeys(array($cursor));
+  }
+
+  protected function newExternalCursorStringForResult($object) {
+    return $object->getChronologicalKey();
+  }
+
+  protected function newPagingMapFromPartialObject($object) {
+    return array(
+      'key' => $object->getChronologicalKey(),
+    );
+  }
+
+  protected function getPrimaryTableAlias() {
+    return 'notification';
   }
 
   public function getQueryApplicationClass() {

src/applications/notification/query/PhabricatorNotificationSearchEngine.php

@@ -134,8 +134,4 @@ final class PhabricatorNotificationSearchEngine
     return $result;
   }
 
-  public function shouldUseOffsetPaging() {
-    return true;
-  }
-
 }

src/applications/transactions/query/PhabricatorEditEngineQuery.php

@@ -46,8 +46,4 @@ final class PhabricatorEditEngineQuery
     return 'PhabricatorTransactionsApplication';
   }
 
-  protected function getResultCursor($object) {
-    return null;
-  }
-
 }