Merge 76d708dd08 into e9170e2de1

app/controllers/api/v1/statuses_controller.rb

@@ -41,7 +41,7 @@ class Api::V1::StatusesController < Api::BaseController
 
     ancestors_limit         = CONTEXT_LIMIT
     descendants_limit       = CONTEXT_LIMIT
-    descendants_depth_limit = nil
+    descendants_depth_limit = CONTEXT_LIMIT
 
     if current_account.nil?
       ancestors_limit         = ANCESTORS_LIMIT
@@ -50,14 +50,14 @@ class Api::V1::StatusesController < Api::BaseController
     end
 
     ancestors_results   = @status.in_reply_to_id.nil? ? [] : @status.ancestors(ancestors_limit, current_account)
-    descendants_results = @status.descendants(descendants_limit, current_account, descendants_depth_limit)
+    descendants_results = @status.descendants(current_account, limit: descendants_limit, depth: descendants_depth_limit).select { |result| result.is_a?(Status) }
     loaded_ancestors    = preload_collection(ancestors_results, Status)
     loaded_descendants  = preload_collection(descendants_results, Status)
 
     @context = Context.new(ancestors: loaded_ancestors, descendants: loaded_descendants)
     statuses = [@status] + @context.ancestors + @context.descendants
 
-    render json: @context, serializer: REST::ContextSerializer, relationships: StatusRelationshipsPresenter.new(statuses, current_user&.account_id)
+    render json: @context, serializer: REST::V1::ContextSerializer, relationships: StatusRelationshipsPresenter.new(statuses, current_user&.account_id)
 
     ActivityPub::FetchAllRepliesWorker.perform_async(@status.id) if !current_account.nil? && @status.should_fetch_replies?
   end

app/controllers/api/v2/statuses_controller.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+class Api::V2::StatusesController < Api::BaseController
+  include Authorization
+
+  before_action -> { authorize_if_got_token! :read, :'read:statuses' }
+  before_action :set_status
+
+  def context
+    descendants_results = @status.descendants(current_account, limit: 3, depth: 2, after_id: nil)
+    @context = Context.new(ancestors: [], descendants: descendants_results)
+    render json: @context, serializer: REST::ContextSerializer
+  end
+
+  private
+
+  def set_status
+    @status = Status.find(params[:id])
+    authorize @status, :show?
+  rescue Mastodon::NotPermittedError
+    not_found
+  end
+end

app/models/concerns/status/threading_concern.rb

@@ -24,8 +24,25 @@ module Status::ThreadingConcern
     find_statuses_from_tree_path(ancestor_ids(limit), account)
   end
 
-  def descendants(limit, account = nil, depth = nil)
-    find_statuses_from_tree_path(descendant_ids(limit, depth), account, promote: true)
+  def descendants(account, limit:, depth:, after_id:)
+    tree = descendant_ids(limit:, depth:, after_id:)
+
+    statuses_map = Status.with_accounts(tree.reject { |id_or_placeholder| id_or_placeholder.is_a?(Context::Gap) }).index_by(&:id)
+    account_ids = statuses_map.values.map(&:account_id).uniq
+    domains = statuses_map.values.filter_map(&:account_domain).uniq
+    relations = account&.relations_map(account_ids, domains) || {}
+
+    statuses_map.values.each do |status|
+      statuses_map[status.id] = Context::FilterGap.new(id: status.id) if StatusFilter.new(status, account, relations).filtered?
+    end
+
+    tree.map do |id_or_placeholder|
+      if id_or_placeholder.is_a?(Context::Gap)
+        id_or_placeholder
+      else
+        statuses_map[id_or_placeholder]
+      end
+    end
   end
 
   def self_replies(limit)
@@ -67,29 +84,51 @@ module Status::ThreadingConcern
     SQL
   end
 
-  def descendant_ids(limit, depth)
-    # use limit + 1 and depth + 1 because 'self' is included
-    depth += 1 if depth.present?
-    limit += 1 if limit.present?
-
-    descendants_with_self = Status.find_by_sql([<<-SQL.squish, id: id, limit: limit, depth: depth])
-      WITH RECURSIVE search_tree(id, path) AS (
-        SELECT id, ARRAY[id]
-        FROM statuses
-        WHERE id = :id
+  def descendant_ids(after_id:, limit:, depth:)
+    # We also fetch nodes that are one level deeper than requested so we can create pagination markers
+    descendant_leaves = Status.find_by_sql([<<-SQL.squish, id: id, after_id: after_id || 0, account_id: account_id, limit: limit, depth: depth])
+      WITH RECURSIVE search_tree(id, account_id, path) AS (
+        (
+          SELECT statuses.id, statuses.account_id, ARRAY[statuses.id]
+          FROM statuses
+          WHERE statuses.in_reply_to_id = :id
+            AND statuses.id > :after_id
+          LIMIT :limit + 1
+        )
       UNION ALL
-        SELECT statuses.id, path || statuses.id
+        SELECT statuses.id, statuses.account_id, path || statuses.id
         FROM search_tree
         JOIN statuses ON statuses.in_reply_to_id = search_tree.id
-        WHERE COALESCE(array_length(path, 1) < :depth, TRUE) AND NOT statuses.id = ANY(path)
+        WHERE array_length(path, 1) < :depth + 1 AND NOT statuses.id = ANY(path)
       )
-      SELECT id
+      SELECT id, path
       FROM search_tree
-      ORDER BY path
-      LIMIT :limit
+      ORDER BY CASE WHEN account_id = :account_id THEN 1 ELSE 0 END DESC, path ASC
     SQL
 
-    descendants_with_self.pluck(:id) - [id]
+    current_top_level_leaf = nil
+    top_level_leaves = 0
+    past_cut_off = false
+
+    descendant_leaves.filter_map do |result|
+      if result.path.size == 1
+        if top_level_leaves == limit
+          past_cut_off = true
+          next Context::LimitGap.new(id: current_top_level_leaf.id)
+        end
+
+        current_top_level_leaf = result
+        top_level_leaves += 1
+      end
+
+      if past_cut_off
+        nil
+      elsif result.path.size > depth # Nodes that are deeper than requested are pagination markers
+        Context::DepthGap.new(id: result.path[result.path.size - 2])
+      else
+        result.id
+      end
+    end
   end
 
   def find_statuses_from_tree_path(ids, account, promote: false)

app/models/context.rb

@@ -2,4 +2,12 @@
 
 class Context < ActiveModelSerializers::Model
   attributes :ancestors, :descendants
+
+  class Gap < ActiveModelSerializers::Model
+    attributes :id
+  end
+
+  class DepthGap < Gap; end
+  class LimitGap < Gap; end
+  class FilterGap < Gap; end
 end

app/serializers/rest/context_serializer.rb

@@ -1,6 +1,44 @@
 # frozen_string_literal: true
 
 class REST::ContextSerializer < ActiveModel::Serializer
-  has_many :ancestors,   serializer: REST::StatusSerializer
-  has_many :descendants, serializer: REST::StatusSerializer
+  class DepthGapSerializer < ActiveModel::Serializer
+    attributes :more_under
+
+    def more_under
+      object.id.to_s
+    end
+  end
+
+  class LimitGapSerializer < ActiveModel::Serializer
+    attributes :more_after
+
+    def more_after
+      object.id.to_s
+    end
+  end
+
+  class FilterGapSerializer < ActiveModel::Serializer
+    attributes :filtered
+
+    def filtered
+      object.id.to_s
+    end
+  end
+
+  def self.serializer_for(model, options)
+    case model.class.name
+    when 'Status'
+      REST::StatusSerializer
+    when 'Context::DepthGap'
+      DepthGapSerializer
+    when 'Context::LimitGap'
+      LimitGapSerializer
+    when 'Context::FilterGap'
+      FilterGapSerializer
+    else
+      super
+    end
+  end
+
+  has_many :descendants
 end

app/serializers/rest/v1/context_serializer.rb

@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class REST::V1::ContextSerializer < ActiveModel::Serializer
+  has_many :ancestors,   serializer: REST::StatusSerializer
+  has_many :descendants, serializer: REST::StatusSerializer
+end

config/routes/api.rb

@@ -356,6 +356,12 @@ namespace :api, format: false do
 
       resources :accounts, only: [:index], module: :notifications
     end
+
+    resources :statuses, only: [] do
+      member do
+        get :context
+      end
+    end
   end
 
   namespace :web do