From 1258efa882b7a0eedc868640eb8e5a9075445ca0 Mon Sep 17 00:00:00 2001
From: Akihiko Odaki <akihiko.odaki.4i@stu.hosei.ac.jp>
Date: Tue, 24 Apr 2018 02:27:35 +0900
Subject: Paginate descendant statuses in public page (#7148)

---
 app/models/concerns/status_threading_concern.rb | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

(limited to 'app/models/concerns/status_threading_concern.rb')

diff --git a/app/models/concerns/status_threading_concern.rb b/app/models/concerns/status_threading_concern.rb
index fffc095ee..a3fd34e94 100644
--- a/app/models/concerns/status_threading_concern.rb
+++ b/app/models/concerns/status_threading_concern.rb
@@ -7,8 +7,8 @@ module StatusThreadingConcern
     find_statuses_from_tree_path(ancestor_ids(limit), account)
   end
 
-  def descendants(account = nil)
-    find_statuses_from_tree_path(descendant_ids, account)
+  def descendants(limit, account = nil, max_child_id = nil, since_child_id = nil, depth = nil)
+    find_statuses_from_tree_path(descendant_ids(limit, max_child_id, since_child_id, depth), account)
   end
 
   private
@@ -46,26 +46,27 @@ module StatusThreadingConcern
     SQL
   end
 
-  def descendant_ids
-    descendant_statuses.pluck(:id)
+  def descendant_ids(limit, max_child_id, since_child_id, depth)
+    descendant_statuses(limit, max_child_id, since_child_id, depth).pluck(:id)
   end
 
-  def descendant_statuses
-    Status.find_by_sql([<<-SQL.squish, id: id])
+  def descendant_statuses(limit, max_child_id, since_child_id, depth)
+    Status.find_by_sql([<<-SQL.squish, id: id, limit: limit, max_child_id: max_child_id, since_child_id: since_child_id, depth: depth])
       WITH RECURSIVE search_tree(id, path)
       AS (
         SELECT id, ARRAY[id]
         FROM statuses
-        WHERE in_reply_to_id = :id
+        WHERE in_reply_to_id = :id AND COALESCE(id < :max_child_id, TRUE) AND COALESCE(id > :since_child_id, TRUE)
         UNION ALL
         SELECT statuses.id, path || statuses.id
         FROM search_tree
         JOIN statuses ON statuses.in_reply_to_id = search_tree.id
-        WHERE NOT statuses.id = ANY(path)
+        WHERE COALESCE(array_length(path, 1) < :depth, TRUE) AND NOT statuses.id = ANY(path)
       )
       SELECT id
       FROM search_tree
       ORDER BY path
+      LIMIT :limit
     SQL
   end
 
-- 
cgit