From 79062bfc2fcf9053c8f859615dfcc27b2da65ee3 Mon Sep 17 00:00:00 2001
From: KMY <tt@kmycode.net>
Date: Sat, 12 Aug 2023 18:22:22 +0900
Subject: [PATCH] Add mutual visibility support

---
 app/controllers/statuses_controller.rb        |  7 +++++-
 .../compose/components/privacy_dropdown.jsx   |  5 +++-
 app/lib/status_reach_finder.rb                |  4 +--
 app/models/concerns/account_interactions.rb   |  4 +++
 app/models/status.rb                          |  1 +
 app/models/status_capability_token.rb         | 25 +++++++++++++++++++
 .../activitypub/activity_presenter.rb         |  4 ++-
 app/serializers/rest/instance_serializer.rb   |  1 +
 .../rest/v1/instance_serializer.rb            |  1 +
 app/services/backup_service.rb                |  2 +-
 app/services/post_status_service.rb           |  4 ++-
 app/services/process_mentions_service.rb      | 13 +++++++++-
 ...12083752_create_status_capability_token.rb | 12 +++++++++
 db/schema.rb                                  | 11 +++++++-
 14 files changed, 85 insertions(+), 9 deletions(-)
 create mode 100644 app/models/status_capability_token.rb
 create mode 100644 db/migrate/20230812083752_create_status_capability_token.rb

diff --git a/app/controllers/statuses_controller.rb b/app/controllers/statuses_controller.rb
index effaba3630..50a8763b72 100644
--- a/app/controllers/statuses_controller.rb
+++ b/app/controllers/statuses_controller.rb
@@ -62,7 +62,12 @@ class StatusesController < ApplicationController
 
   def set_status
     @status = @account.statuses.find(params[:id])
-    authorize @status, :show?
+
+    if request.authorization.present? && request.authorization.match(/^Bearer /i)
+      raise Mastodon::NotPermittedError unless @status.capability_tokens.find_by(token: request.authorization.gsub(/^Bearer /i, ''))
+    else
+      authorize @status, :show?
+    end
   rescue Mastodon::NotPermittedError
     not_found
   end
diff --git a/app/javascript/mastodon/features/compose/components/privacy_dropdown.jsx b/app/javascript/mastodon/features/compose/components/privacy_dropdown.jsx
index 2fe7d6e1f6..22f6a44c2b 100644
--- a/app/javascript/mastodon/features/compose/components/privacy_dropdown.jsx
+++ b/app/javascript/mastodon/features/compose/components/privacy_dropdown.jsx
@@ -24,6 +24,8 @@ const messages = defineMessages({
   login_long: { id: 'privacy.login.long', defaultMessage: 'Login user only' },
   private_short: { id: 'privacy.private.short', defaultMessage: 'Followers only' },
   private_long: { id: 'privacy.private.long', defaultMessage: 'Visible for followers only' },
+  mutual_short: { id: 'privacy.mutual.short', defaultMessage: 'Mutual' },
+  mutual_long: { id: 'privacy.mutual.long', defaultMessage: 'Mutual follows only' },
   direct_short: { id: 'privacy.direct.short', defaultMessage: 'Mentioned people only' },
   direct_long: { id: 'privacy.direct.long', defaultMessage: 'Visible for mentioned users only' },
   change_privacy: { id: 'privacy.change', defaultMessage: 'Adjust status privacy' },
@@ -119,7 +121,7 @@ class PrivacyDropdownMenu extends PureComponent {
   setFocusRef = c => {
     this.focusedItem = c;
   };
-
+  
   render () {
     const { style, items, value } = this.props;
 
@@ -231,6 +233,7 @@ class PrivacyDropdown extends PureComponent {
       { icon: 'cloud', value: 'public_unlisted', text: formatMessage(messages.public_unlisted_short), meta: formatMessage(messages.public_unlisted_long) },
       { icon: 'key', value: 'login', text: formatMessage(messages.login_short), meta: formatMessage(messages.login_long) },
       { icon: 'unlock', value: 'unlisted', text: formatMessage(messages.unlisted_short), meta: formatMessage(messages.unlisted_long) },
+      { icon: 'exchange', value: 'mutual', text: formatMessage(messages.mutual_short), meta: formatMessage(messages.mutual_long) },
       { icon: 'lock', value: 'private', text: formatMessage(messages.private_short), meta: formatMessage(messages.private_long) },
       { icon: 'at', value: 'direct', text: formatMessage(messages.direct_short), meta: formatMessage(messages.direct_long) },
     ];
diff --git a/app/lib/status_reach_finder.rb b/app/lib/status_reach_finder.rb
index 6cce4e04fb..6117949f9f 100644
--- a/app/lib/status_reach_finder.rb
+++ b/app/lib/status_reach_finder.rb
@@ -29,7 +29,7 @@ class StatusReachFinder
 
     if @status.reblog?
       []
-    else
+    elsif !@status.limited_visibility?
       Account.where(id: reached_account_ids).where.not(domain: banned_domains).inboxes
     end
   end
@@ -37,7 +37,7 @@ class StatusReachFinder
   def reached_account_inboxes_for_misskey
     if @status.reblog?
       []
-    else
+    elsif !@status.limited_visibility?
       Account.where(id: reached_account_ids).where(domain: banned_domains_for_misskey).inboxes
     end
   end
diff --git a/app/models/concerns/account_interactions.rb b/app/models/concerns/account_interactions.rb
index 649e64e398..42a42e8f9f 100644
--- a/app/models/concerns/account_interactions.rb
+++ b/app/models/concerns/account_interactions.rb
@@ -303,6 +303,10 @@ module AccountInteractions
     end
   end
 
+  def mutuals
+    followers.merge(Account.where(id: following))
+  end
+
   def relations_map(account_ids, domains = nil, **options)
     relations = {
       blocked_by: Account.blocked_by_map(account_ids, id),
diff --git a/app/models/status.rb b/app/models/status.rb
index 348a1e697b..99bc0290f0 100644
--- a/app/models/status.rb
+++ b/app/models/status.rb
@@ -79,6 +79,7 @@ class Status < ApplicationRecord
   has_many :references, through: :reference_objects, class_name: 'Status', source: :target_status
   has_many :referenced_by_status_objects, foreign_key: 'target_status_id', class_name: 'StatusReference', inverse_of: :target_status, dependent: :destroy
   has_many :referenced_by_statuses, through: :referenced_by_status_objects, class_name: 'Status', source: :status
+  has_many :capability_tokens, class_name: 'StatusCapabilityToken', inverse_of: :status, dependent: :destroy
 
   has_and_belongs_to_many :tags
   has_and_belongs_to_many :preview_cards
diff --git a/app/models/status_capability_token.rb b/app/models/status_capability_token.rb
new file mode 100644
index 0000000000..6bd7916497
--- /dev/null
+++ b/app/models/status_capability_token.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+# == Schema Information
+#
+# Table name: status_capability_tokens
+#
+#  id         :bigint(8)        not null, primary key
+#  status_id  :bigint(8)        not null
+#  token      :string
+#  created_at :datetime         not null
+#  updated_at :datetime         not null
+#
+class StatusCapabilityToken < ApplicationRecord
+  belongs_to :status
+
+  validates :token, presence: true
+
+  before_validation :generate_token, on: :create
+
+  private
+
+  def generate_token
+    self.token = Doorkeeper::OAuth::Helpers::UniqueToken.generate
+  end
+end
diff --git a/app/presenters/activitypub/activity_presenter.rb b/app/presenters/activitypub/activity_presenter.rb
index 9524e64179..fe04396cad 100644
--- a/app/presenters/activitypub/activity_presenter.rb
+++ b/app/presenters/activitypub/activity_presenter.rb
@@ -4,7 +4,7 @@ class ActivityPub::ActivityPresenter < ActiveModelSerializers::Model
   attributes :id, :type, :actor, :published, :to, :cc, :virtual_object
 
   class << self
-    def from_status(status, allow_inlining: true, for_misskey: false)
+    def from_status(status, use_bearcap: true, allow_inlining: true, for_misskey: false)
       new.tap do |presenter|
         presenter.id        = ActivityPub::TagManager.instance.activity_uri_for(status)
         presenter.type      = status.reblog? ? 'Announce' : 'Create'
@@ -20,6 +20,8 @@ class ActivityPub::ActivityPresenter < ActiveModelSerializers::Model
             else
               ActivityPub::TagManager.instance.uri_for(status.proper)
             end
+          elsif status.limited_visibility? && use_bearcap
+            "bear:?#{{ u: ActivityPub::TagManager.instance.uri_for(status.proper), t: status.capability_tokens.first.token }.to_query}"
           else
             status.proper
           end
diff --git a/app/serializers/rest/instance_serializer.rb b/app/serializers/rest/instance_serializer.rb
index 2dd360ab35..3ed35d9c32 100644
--- a/app/serializers/rest/instance_serializer.rb
+++ b/app/serializers/rest/instance_serializer.rb
@@ -118,6 +118,7 @@ class REST::InstanceSerializer < ActiveModel::Serializer
       :kmyblue_reaction_deck,
       :kmyblue_visibility_login,
       :status_reference,
+      :visibility_mutual,
     ]
 
     capabilities << :profile_search unless Chewy.enabled?
diff --git a/app/serializers/rest/v1/instance_serializer.rb b/app/serializers/rest/v1/instance_serializer.rb
index c0c30b5a03..e6d7f35e10 100644
--- a/app/serializers/rest/v1/instance_serializer.rb
+++ b/app/serializers/rest/v1/instance_serializer.rb
@@ -127,6 +127,7 @@ class REST::V1::InstanceSerializer < ActiveModel::Serializer
       :kmyblue_reaction_deck,
       :kmyblue_visibility_login,
       :status_reference,
+      :visibility_mutual,
     ]
 
     capabilities << :profile_search unless Chewy.enabled?
diff --git a/app/services/backup_service.rb b/app/services/backup_service.rb
index 3ef0366c3c..5de64a8a39 100644
--- a/app/services/backup_service.rb
+++ b/app/services/backup_service.rb
@@ -32,7 +32,7 @@ class BackupService < BaseService
       add_comma = true
 
       file.write(statuses.map do |status|
-        item = serialize_payload(ActivityPub::ActivityPresenter.from_status(status), ActivityPub::ActivitySerializer)
+        item = serialize_payload(ActivityPub::ActivityPresenter.from_status(status, use_bearcap: false), ActivityPub::ActivitySerializer)
         item.delete('@context')
 
         unless item[:type] == 'Announce' || item[:object][:attachment].blank?
diff --git a/app/services/post_status_service.rb b/app/services/post_status_service.rb
index eb5038b332..030dc8441e 100644
--- a/app/services/post_status_service.rb
+++ b/app/services/post_status_service.rb
@@ -74,6 +74,7 @@ class PostStatusService < BaseService
                      end) || @options[:spoiler_text].present?
     @text         = @options.delete(:spoiler_text) if @text.blank? && @options[:spoiler_text].present?
     @visibility   = @options[:visibility] || @account.user&.setting_default_privacy
+    @visibility   = :limited if @options[:visibility] == 'mutual'
     @visibility   = :unlisted if (@visibility&.to_sym == :public || @visibility&.to_sym == :public_unlisted || @visibility&.to_sym == :login) && @account.silenced?
     @visibility   = :public_unlisted if @visibility&.to_sym == :public && !@options[:force_visibility] && !@options[:application]&.superapp && @account.user&.setting_public_post_to_unlisted
     @searchability = searchability
@@ -113,7 +114,7 @@ class PostStatusService < BaseService
 
   def process_status!
     @status = @account.statuses.new(status_attributes)
-    process_mentions_service.call(@status, save_records: false)
+    process_mentions_service.call(@status, limited_type: @status.limited_visibility? ? 'mutual' : '', save_records: false)
     safeguard_mentions!(@status)
 
     UpdateStatusExpirationService.new.call(@status)
@@ -122,6 +123,7 @@ class PostStatusService < BaseService
     # the media attachments when the status is created
     ApplicationRecord.transaction do
       @status.save!
+      @status.capability_tokens.create! if @status.limited_visibility?
     end
   end
 
diff --git a/app/services/process_mentions_service.rb b/app/services/process_mentions_service.rb
index f3fbb80210..16cbad1f75 100644
--- a/app/services/process_mentions_service.rb
+++ b/app/services/process_mentions_service.rb
@@ -7,8 +7,9 @@ class ProcessMentionsService < BaseService
   # and create local mention pointers
   # @param [Status] status
   # @param [Boolean] save_records Whether to save records in database
-  def call(status, save_records: true)
+  def call(status, limited_type: '', save_records: true)
     @status = status
+    @limited_type = limited_type
     @save_records = save_records
 
     return unless @status.local?
@@ -62,6 +63,8 @@ class ProcessMentionsService < BaseService
       "@#{mentioned_account.acct}"
     end
 
+    process_mutual! if @limited_type == 'mutual'
+
     @status.save! if @save_records
   end
 
@@ -92,4 +95,12 @@ class ProcessMentionsService < BaseService
   def mention_undeliverable?(mentioned_account)
     mentioned_account.nil? || (!mentioned_account.local? && !mentioned_account.activitypub?)
   end
+
+  def process_mutual!
+    mentioned_account_ids = @current_mentions.map(&:account_id)
+
+    @status.account.mutuals.find_each do |target_account|
+      @current_mentions << @status.mentions.new(silent: true, account: target_account) unless mentioned_account_ids.include?(target_account.id)
+    end
+  end
 end
diff --git a/db/migrate/20230812083752_create_status_capability_token.rb b/db/migrate/20230812083752_create_status_capability_token.rb
new file mode 100644
index 0000000000..f4deaa9c9e
--- /dev/null
+++ b/db/migrate/20230812083752_create_status_capability_token.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+class CreateStatusCapabilityToken < ActiveRecord::Migration[7.0]
+  def change
+    create_table :status_capability_tokens do |t|
+      t.belongs_to :status, null: false, foreign_key: { on_delete: :cascade }
+      t.string :token
+      t.datetime :created_at, null: false
+      t.datetime :updated_at, null: false
+    end
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 75d7264df6..593f282fab 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.0].define(version: 2023_08_04_222017) do
+ActiveRecord::Schema[7.0].define(version: 2023_08_12_083752) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
 
@@ -1029,6 +1029,14 @@ ActiveRecord::Schema[7.0].define(version: 2023_08_04_222017) do
     t.index ["var"], name: "index_site_uploads_on_var", unique: true
   end
 
+  create_table "status_capability_tokens", force: :cascade do |t|
+    t.bigint "status_id", null: false
+    t.string "token"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["status_id"], name: "index_status_capability_tokens_on_status_id"
+  end
+
   create_table "status_edits", force: :cascade do |t|
     t.bigint "status_id", null: false
     t.bigint "account_id"
@@ -1395,6 +1403,7 @@ ActiveRecord::Schema[7.0].define(version: 2023_08_04_222017) do
   add_foreign_key "scheduled_statuses", "accounts", on_delete: :cascade
   add_foreign_key "session_activations", "oauth_access_tokens", column: "access_token_id", name: "fk_957e5bda89", on_delete: :cascade
   add_foreign_key "session_activations", "users", name: "fk_e5fda67334", on_delete: :cascade
+  add_foreign_key "status_capability_tokens", "statuses", on_delete: :cascade
   add_foreign_key "status_edits", "accounts", on_delete: :nullify
   add_foreign_key "status_edits", "statuses", on_delete: :cascade
   add_foreign_key "status_pins", "accounts", name: "fk_d4cb435b62", on_delete: :cascade