Private visibility on statuses prevents non-followers from seeing those

Filters out hidden stream entries from Atom feed
Blocks now generate hidden stream entries, can be used to federate blocks
Private statuses cannot be reblogged (generates generic 422 error for now)
POST /api/v1/statuses now takes visibility=(public|unlisted|private) param instead of unlisted boolean
Statuses JSON now contains visibility=(public|unlisted|private) field

app/models/status.rb

@@ -5,7 +5,7 @@ class Status < ApplicationRecord
   include Streamable
   include Cacheable
 
-  enum visibility: [:public, :unlisted], _suffix: :visibility
+  enum visibility: [:public, :unlisted, :private], _suffix: :visibility
 
   belongs_to :account, inverse_of: :statuses
 
@@ -66,19 +66,19 @@ class Status < ApplicationRecord
     content
   end
 
-  def reblogs_count
-    attributes['reblogs_count'] || reblogs.count
+  def hidden?
+    private_visibility?
   end
 
-  def favourites_count
-    attributes['favourites_count'] || favourites.count
+  def permitted?(other_account = nil)
+    private_visibility? ? (account.id == other_account&.id || other_account&.following?(account)) : true
   end
 
   def ancestors(account = nil)
     ids      = (Status.find_by_sql(['WITH RECURSIVE search_tree(id, in_reply_to_id, path) AS (SELECT id, in_reply_to_id, ARRAY[id] FROM statuses WHERE id = ? UNION ALL SELECT statuses.id, statuses.in_reply_to_id, path || statuses.id FROM search_tree JOIN statuses ON statuses.id = search_tree.in_reply_to_id WHERE NOT statuses.id = ANY(path)) SELECT id FROM search_tree ORDER BY path DESC', id]) - [self]).pluck(:id)
     statuses = Status.where(id: ids).with_includes.group_by(&:id)
     results  = ids.map { |id| statuses[id].first }
-    results  = results.reject { |status| account.blocking?(status.account) } unless account.nil?
+    results  = results.reject { |status| filter_from_context?(status, account) }
 
     results
   end
@@ -87,7 +87,7 @@ class Status < ApplicationRecord
     ids      = (Status.find_by_sql(['WITH RECURSIVE search_tree(id, path) AS (SELECT id, ARRAY[id] FROM statuses WHERE id = ? 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)) SELECT id FROM search_tree ORDER BY path', id]) - [self]).pluck(:id)
     statuses = Status.where(id: ids).with_includes.group_by(&:id)
     results  = ids.map { |id| statuses[id].first }
-    results  = results.reject { |status| account.blocking?(status.account) } unless account.nil?
+    results  = results.reject { |status| filter_from_context?(status, account) }
 
     results
   end
@@ -128,6 +128,14 @@ class Status < ApplicationRecord
       select('reblog_of_id').where(reblog_of_id: status_ids).where(account_id: account_id).map { |s| [s.reblog_of_id, true] }.to_h
     end
 
+    def permitted_for(target_account, account)
+      if account&.id == target_account.id || account&.following?(target_account)
+        self
+      else
+        where.not(visibility: :private)
+      end
+    end
+
     def reload_stale_associations!(cached_items)
       account_ids = []
 
@@ -161,5 +169,12 @@ class Status < ApplicationRecord
   before_validation do
     text.strip!
     self.in_reply_to_account_id = thread.account_id if reply?
+    self.visibility             = :public if visibility.nil?
+  end
+
+  private
+
+  def filter_from_context?(status, account)
+    account&.blocking?(status.account) || !status.permitted?(account)
   end
 end