Fix rubocop issues, introduce usage of frozen literal to improve performance

.rubocop.yml

@@ -18,9 +18,29 @@ Metrics/MethodLength:
   CountComments: false
   Max: 10
 
-Metrics/ModuleLength:
+Metrics/AbcSize:
   Max: 100
 
+Metrics/BlockNesting:
+  Max: 3
+
+Metrics/ClassLength:
+  CountComments: false
+  Max: 200
+
+Metrics/CyclomaticComplexity:
+  Max: 15
+
+Metrics/MethodLength:
+  Max: 55
+
+Metrics/ModuleLength:
+  CountComments: false
+  Max: 200
+
+Metrics/PerceivedComplexity:
+  Max: 10
+
 Metrics/ParameterLists:
   Max: 4
   CountKeywordArgs: true
@@ -37,10 +57,10 @@ Style/Documentation:
   Enabled: false
 
 Style/DoubleNegation:
-  Enabled: false
+  Enabled: true
 
 Style/FrozenStringLiteralComment:
-  Enabled: false
+  Enabled: true
 
 Style/SpaceInsideHashLiteralBraces:
   EnforcedStyle: space
@@ -51,10 +71,18 @@ Style/TrailingCommaInLiteral:
 Style/RegexpLiteral:
   Enabled: false
 
+Style/Lambda:
+  Enabled: false
+
+Rails/HasAndBelongsToMany:
+  Enabled: false
+
 AllCops:
-  TargetRubyVersion: 2.2
+  TargetRubyVersion: 2.3
   Exclude:
   - 'spec/**/*'
   - 'db/**/*'
   - 'app/views/**/*'
   - 'config/**/*'
+  - 'bin/*'
+  - 'Rakefile'

Gemfile

+# frozen_string_literal: true
+
 source 'https://rubygems.org'
 
 gem 'rails', '5.0.0.1'

app/channels/application_cable/channel.rb

+# frozen_string_literal: true
+
 module ApplicationCable
   class Channel < ActionCable::Channel::Base
     protected

app/channels/application_cable/connection.rb

+# frozen_string_literal: true
+
 module ApplicationCable
   class Connection < ActionCable::Connection::Base
     identified_by :current_user

app/channels/hashtag_channel.rb

+# frozen_string_literal: true
+
 class HashtagChannel < ApplicationCable::Channel
   def subscribed
     tag = params[:tag].downcase

app/channels/public_channel.rb

+# frozen_string_literal: true
+
 class PublicChannel < ApplicationCable::Channel
   def subscribed
     stream_from 'timeline:public', lambda { |encoded_message|

app/channels/timeline_channel.rb

+# frozen_string_literal: true
+
 class TimelineChannel < ApplicationCable::Channel
   def subscribed
     stream_from "timeline:#{current_user.account_id}"

app/controllers/about_controller.rb

+# frozen_string_literal: true
+
 class AboutController < ApplicationController
   before_action :set_body_classes
 

app/controllers/accounts_controller.rb

+# frozen_string_literal: true
+
 class AccountsController < ApplicationController
   layout 'public'
 
@@ -41,10 +43,7 @@ class AccountsController < ApplicationController
   end
 
   def set_link_headers
-    response.headers['Link'] = LinkHeader.new([
-      [webfinger_account_url, [['rel', 'lrdd'], ['type', 'application/xrd+xml']]],
-      [account_url(@account, format: 'atom'), [['rel', 'alternate'], ['type', 'application/atom+xml']]]
-    ])
+    response.headers['Link'] = LinkHeader.new([[webfinger_account_url, [%w(rel lrdd), %w(type application/xrd+xml)]], [account_url(@account, format: 'atom'), [%w(rel alternate), %w(type application/atom+xml)]]])
   end
 
   def webfinger_account_url

app/controllers/api/salmon_controller.rb

+# frozen_string_literal: true
+
 class Api::SalmonController < ApiController
   before_action :set_account
   respond_to :txt

app/controllers/api/subscriptions_controller.rb

+# frozen_string_literal: true
+
 class Api::SubscriptionsController < ApiController
   before_action :set_account
   respond_to :txt

app/controllers/api/v1/accounts_controller.rb

+# frozen_string_literal: true
+
 class Api::V1::AccountsController < ApiController
   before_action -> { doorkeeper_authorize! :read }, except: [:follow, :unfollow, :block, :unblock]
   before_action -> { doorkeeper_authorize! :follow }, only: [:follow, :unfollow, :block, :unblock]
@@ -20,7 +22,7 @@ class Api::V1::AccountsController < ApiController
     @accounts = results.map { |f| accounts[f.target_account_id] }
 
     next_path = following_api_v1_account_url(max_id: results.last.id)    if results.size == DEFAULT_ACCOUNTS_LIMIT
-    prev_path = following_api_v1_account_url(since_id: results.first.id) if results.size > 0
+    prev_path = following_api_v1_account_url(since_id: results.first.id) unless results.empty?
 
     set_pagination_headers(next_path, prev_path)
 
@@ -33,7 +35,7 @@ class Api::V1::AccountsController < ApiController
     @accounts = results.map { |f| accounts[f.account_id] }
 
     next_path = followers_api_v1_account_url(max_id: results.last.id)    if results.size == DEFAULT_ACCOUNTS_LIMIT
-    prev_path = followers_api_v1_account_url(since_id: results.first.id) if results.size > 0
+    prev_path = followers_api_v1_account_url(since_id: results.first.id) unless results.empty?
 
     set_pagination_headers(next_path, prev_path)
 
@@ -56,7 +58,7 @@ class Api::V1::AccountsController < ApiController
     set_maps(@statuses)
 
     next_path = statuses_api_v1_account_url(max_id: @statuses.last.id)    if @statuses.size == DEFAULT_STATUSES_LIMIT
-    prev_path = statuses_api_v1_account_url(since_id: @statuses.first.id) if @statuses.size > 0
+    prev_path = statuses_api_v1_account_url(since_id: @statuses.first.id) unless @statuses.empty?
 
     set_pagination_headers(next_path, prev_path)
   end

app/controllers/api/v1/apps_controller.rb

+# frozen_string_literal: true
+
 class Api::V1::AppsController < ApiController
   respond_to :json
 

app/controllers/api/v1/follows_controller.rb

+# frozen_string_literal: true
+
 class Api::V1::FollowsController < ApiController
   before_action -> { doorkeeper_authorize! :follow }
   before_action :require_user!

app/controllers/api/v1/media_controller.rb

+# frozen_string_literal: true
+
 class Api::V1::MediaController < ApiController
   before_action -> { doorkeeper_authorize! :write }
   before_action :require_user!

app/controllers/api/v1/statuses_controller.rb

+# frozen_string_literal: true
+
 class Api::V1::StatusesController < ApiController
   before_action -> { doorkeeper_authorize! :read }, except: [:create, :destroy, :reblog, :unreblog, :favourite, :unfavourite]
   before_action -> { doorkeeper_authorize! :write }, only:  [:create, :destroy, :reblog, :unreblog, :favourite, :unfavourite]
@@ -10,7 +12,7 @@ class Api::V1::StatusesController < ApiController
   end
 
   def context
-    @context = OpenStruct.new({ ancestors: @status.ancestors, descendants: @status.descendants })
+    @context = OpenStruct.new(ancestors: @status.ancestors, descendants: @status.descendants)
     set_maps([@status] + @context[:ancestors] + @context[:descendants])
   end
 
@@ -20,7 +22,7 @@ class Api::V1::StatusesController < ApiController
     @accounts = results.map { |r| accounts[r.account_id] }
 
     next_path = reblogged_by_api_v1_status_url(max_id: results.last.id)    if results.size == DEFAULT_ACCOUNTS_LIMIT
-    prev_path = reblogged_by_api_v1_status_url(since_id: results.first.id) if results.size > 0
+    prev_path = reblogged_by_api_v1_status_url(since_id: results.first.id) unless results.empty?
 
     set_pagination_headers(next_path, prev_path)
 
@@ -33,7 +35,7 @@ class Api::V1::StatusesController < ApiController
     @accounts = results.map { |f| accounts[f.account_id] }
 
     next_path = favourited_by_api_v1_status_url(max_id: results.last.id)    if results.size == DEFAULT_ACCOUNTS_LIMIT
-    prev_path = favourited_by_api_v1_status_url(since_id: results.first.id) if results.size > 0
+    prev_path = favourited_by_api_v1_status_url(since_id: results.first.id) unless results.empty?
 
     set_pagination_headers(next_path, prev_path)
 

app/controllers/api/v1/timelines_controller.rb

+# frozen_string_literal: true
+
 class Api::V1::TimelinesController < ApiController
   before_action -> { doorkeeper_authorize! :read }
   before_action :require_user!, only: [:home, :mentions]
@@ -10,7 +12,7 @@ class Api::V1::TimelinesController < ApiController
     set_maps(@statuses)
 
     next_path = api_v1_home_timeline_url(max_id: @statuses.last.id)    if @statuses.size == DEFAULT_STATUSES_LIMIT
-    prev_path = api_v1_home_timeline_url(since_id: @statuses.first.id) if @statuses.size > 0
+    prev_path = api_v1_home_timeline_url(since_id: @statuses.first.id) unless @statuses.empty?
 
     set_pagination_headers(next_path, prev_path)
 
@@ -23,7 +25,7 @@ class Api::V1::TimelinesController < ApiController
     set_maps(@statuses)
 
     next_path = api_v1_mentions_timeline_url(max_id: @statuses.last.id)    if @statuses.size == DEFAULT_STATUSES_LIMIT
-    prev_path = api_v1_mentions_timeline_url(since_id: @statuses.first.id) if @statuses.size > 0
+    prev_path = api_v1_mentions_timeline_url(since_id: @statuses.first.id) unless @statuses.empty?
 
     set_pagination_headers(next_path, prev_path)
 
@@ -36,7 +38,7 @@ class Api::V1::TimelinesController < ApiController
     set_maps(@statuses)
 
     next_path = api_v1_public_timeline_url(max_id: @statuses.last.id)    if @statuses.size == DEFAULT_STATUSES_LIMIT
-    prev_path = api_v1_public_timeline_url(since_id: @statuses.first.id) if @statuses.size > 0
+    prev_path = api_v1_public_timeline_url(since_id: @statuses.first.id) unless @statuses.empty?
 
     set_pagination_headers(next_path, prev_path)
 
@@ -50,7 +52,7 @@ class Api::V1::TimelinesController < ApiController
     set_maps(@statuses)
 
     next_path = api_v1_hashtag_timeline_url(params[:id], max_id: @statuses.last.id)    if @statuses.size == DEFAULT_STATUSES_LIMIT
-    prev_path = api_v1_hashtag_timeline_url(params[:id], since_id: @statuses.first.id) if @statuses.size > 0
+    prev_path = api_v1_hashtag_timeline_url(params[:id], since_id: @statuses.first.id) unless @statuses.empty?
 
     set_pagination_headers(next_path, prev_path)
 

app/controllers/api_controller.rb

+# frozen_string_literal: true
+
 class ApiController < ApplicationController
   DEFAULT_STATUSES_LIMIT = 20
   DEFAULT_ACCOUNTS_LIMIT = 40
@@ -51,8 +53,8 @@ class ApiController < ApplicationController
 
   def set_pagination_headers(next_path = nil, prev_path = nil)
     links = []
-    links << [next_path, [['rel', 'next']]] if next_path
-    links << [prev_path, [['rel', 'prev']]] if prev_path
+    links << [next_path, [%w(rel next)]] if next_path
+    links << [prev_path, [%w(rel prev)]] if prev_path
     response.headers['Link'] = LinkHeader.new(links)
   end
 
@@ -76,7 +78,7 @@ class ApiController < ApplicationController
     render json: {}, status: 200
   end
 
-  def set_maps(statuses)
+  def set_maps(statuses) # rubocop:disable Style/AccessorMethodName
     if current_account.nil?
       @reblogs_map    = {}
       @favourites_map = {}

app/controllers/application_controller.rb

+# frozen_string_literal: true
+
 class ApplicationController < ActionController::Base
   # Prevent CSRF attacks by raising an exception.
   # For APIs, you may want to use :null_session instead.

app/controllers/auth/confirmations_controller.rb

+# frozen_string_literal: true
+
 class Auth::ConfirmationsController < Devise::ConfirmationsController
   layout 'auth'
 end

app/controllers/auth/passwords_controller.rb

+# frozen_string_literal: true
+
 class Auth::PasswordsController < Devise::PasswordsController
   layout 'auth'
 end

app/controllers/auth/registrations_controller.rb

+# frozen_string_literal: true
+
 class Auth::RegistrationsController < Devise::RegistrationsController
   layout 'auth'
 

app/controllers/auth/sessions_controller.rb

+# frozen_string_literal: true
+
 class Auth::SessionsController < Devise::SessionsController
   include Devise::Controllers::Rememberable
 

app/controllers/home_controller.rb

+# frozen_string_literal: true
+
 class HomeController < ApplicationController
   before_action :authenticate_user!
 

app/controllers/media_controller.rb

+# frozen_string_literal: true
+
 class MediaController < ApplicationController
   before_action :set_media_attachment
 

app/controllers/oauth/authorizations_controller.rb

+# frozen_string_literal: true
+
 class Oauth::AuthorizationsController < Doorkeeper::AuthorizationsController
   skip_before_action :authenticate_resource_owner!
 

app/controllers/settings/preferences_controller.rb

+# frozen_string_literal: true
+
 class Settings::PreferencesController < ApplicationController
   layout 'auth'
 

app/controllers/settings/profiles_controller.rb

+# frozen_string_literal: true
+
 class Settings::ProfilesController < ApplicationController
   layout 'auth'
 

app/controllers/stream_entries_controller.rb

+# frozen_string_literal: true
+
 class StreamEntriesController < ApplicationController
   layout 'public'
 
@@ -29,9 +31,7 @@ class StreamEntriesController < ApplicationController
   end
 
   def set_link_headers
-    response.headers['Link'] = LinkHeader.new([
-      [account_stream_entry_url(@account, @stream_entry, format: 'atom'), [['rel', 'alternate'], ['type', 'application/atom+xml']]]
-    ])
+    response.headers['Link'] = LinkHeader.new([[account_stream_entry_url(@account, @stream_entry, format: 'atom'), [%w(rel alternate), %w(type application/atom+xml)]]])
   end
 
   def set_stream_entry

app/controllers/tags_controller.rb

+# frozen_string_literal: true
+
 class TagsController < ApplicationController
   layout 'public'
 

app/controllers/xrd_controller.rb

+# frozen_string_literal: true
+
 class XrdController < ApplicationController
   before_action :set_default_format_json, only: :webfinger
   before_action :set_default_format_xml, only: :host_meta
@@ -26,11 +28,11 @@ class XrdController < ApplicationController
   private
 
   def set_default_format_xml
-    request.format = 'xml' if request.headers["HTTP_ACCEPT"].nil? && params[:format].nil?
+    request.format = 'xml' if request.headers['HTTP_ACCEPT'].nil? && params[:format].nil?
   end
 
   def set_default_format_json
-    request.format = 'json' if request.headers["HTTP_ACCEPT"].nil? && params[:format].nil?
+    request.format = 'json' if request.headers['HTTP_ACCEPT'].nil? && params[:format].nil?
   end
 
   def username_from_resource
@@ -44,14 +46,14 @@ class XrdController < ApplicationController
 
   def pem_to_magic_key(public_key)
     modulus, exponent = [public_key.n, public_key.e].map do |component|
-      result = ''
+      result = []
 
       until component.zero?
         result << [component % 256].pack('C')
         component >>= 8
       end
 
-      result.reverse!
+      result.reverse.join
     end
 
     (['RSA'] + [modulus, exponent].map { |n| Base64.urlsafe_encode64(n) }).join('.')

app/helpers/about_helper.rb

+# frozen_string_literal: true
+
 module AboutHelper
 end

app/helpers/accounts_helper.rb

+# frozen_string_literal: true
+
 module AccountsHelper
   def pagination_options
     {
-      previous_label: "#{fa_icon('chevron-left')} Prev".html_safe,
-      next_label: "Next #{fa_icon('chevron-right')}".html_safe,
+      previous_label: safe_join([fa_icon('chevron-left'), 'Prev'], ' '),
+      next_label: safe_join(['Next', fa_icon('chevron-right')], ' '),
       inner_window: 1,
-      outer_window: 0
+      outer_window: 0,
     }
   end
 end

app/helpers/application_helper.rb

+# frozen_string_literal: true
+
 module ApplicationHelper
   def active_nav_class(path)
     current_page?(path) ? 'active' : ''

app/helpers/atom_builder_helper.rb

+# frozen_string_literal: true
+
 module AtomBuilderHelper
   def stream_updated_at
-    @account.stream_entries.last ? (@account.updated_at > @account.stream_entries.last.created_at ? @account.updated_at : @account.stream_entries.last.created_at) : @account.updated_at
+    if @account.stream_entries.last
+      (@account.updated_at > @account.stream_entries.last.created_at ? @account.updated_at : @account.stream_entries.last.created_at)
+    else
+      @account.updated_at
+    end
   end
 
   def entry(xml, is_root = false, &block)
@@ -98,7 +104,7 @@ module AtomBuilderHelper
   end
 
   def in_reply_to(xml, uri, url)
-    xml['thr'].send('in-reply-to', { ref: uri, href: url, type: 'text/html' })
+    xml['thr'].send('in-reply-to', ref: uri, href: url, type: 'text/html')
   end
 
   def link_mention(xml, account)

app/helpers/home_helper.rb

+# frozen_string_literal: true
+
 module HomeHelper
   def default_props
     {
       token: @token,
-      account: render(file: 'api/v1/accounts/show', locals: { account: current_user.account }, formats: :json)
+      account: render(file: 'api/v1/accounts/show', locals: { account: current_user.account }, formats: :json),
     }
   end
 end

app/helpers/routing_helper.rb

+# frozen_string_literal: true
+
 module RoutingHelper
   extend ActiveSupport::Concern
   include Rails.application.routes.url_helpers

app/helpers/stream_entries_helper.rb

+# frozen_string_literal: true
+
 module StreamEntriesHelper
   def display_name(account)
     account.display_name.blank? ? account.username : account.display_name

app/helpers/tags_helper.rb

+# frozen_string_literal: true
+
 module TagsHelper
 end

app/helpers/xrd_helper.rb

+# frozen_string_literal: true
+
 module XrdHelper
 end

app/lib/feed_manager.rb

+# frozen_string_literal: true
+
 require 'singleton'
 
 class FeedManager
@@ -60,29 +62,29 @@ class FeedManager
   private
 
   def redis
-    $redis
+    Redis.current
   end
 
   def filter_from_home?(status, receiver)
     should_filter = false
 
-    if status.reply? && !status.thread.account.nil?                                     # Filter out if it's a reply
-      should_filter = !receiver.following?(status.thread.account)                       # and I'm not following the person it's a reply to
-      should_filter = should_filter && !(receiver.id == status.thread.account_id)       # and it's not a reply to me
-      should_filter = should_filter && !(status.account_id == status.thread.account_id) # and it's not a self-reply
-    elsif status.reblog?                                                                # Filter out a reblog
-      should_filter = receiver.blocking?(status.reblog.account)                         # if I'm blocking the reblogged person
+    if status.reply? && !status.thread.account.nil?                      # Filter out if it's a reply
+      should_filter   = !receiver.following?(status.thread.account)      # and I'm not following the person it's a reply to
+      should_filter &&= !(receiver.id == status.thread.account_id)       # and it's not a reply to me
+      should_filter &&= !(status.account_id == status.thread.account_id) # and it's not a self-reply
+    elsif status.reblog?                                                 # Filter out a reblog
+      should_filter = receiver.blocking?(status.reblog.account)          # if I'm blocking the reblogged person
     end
 
     should_filter
   end
 
   def filter_from_mentions?(status, receiver)
-    should_filter = receiver.id == status.account_id                             # Filter if I'm mentioning myself
-    should_filter = should_filter || receiver.blocking?(status.account)          # or it's from someone I blocked
+    should_filter   = receiver.id == status.account_id            # Filter if I'm mentioning myself
+    should_filter ||= receiver.blocking?(status.account)          # or it's from someone I blocked
 
-    if status.reply? && !status.thread.account.nil?                              # or it's a reply
-      should_filter = should_filter || receiver.blocking?(status.thread.account) # to a user I blocked
+    if status.reply? && !status.thread.account.nil?               # or it's a reply
+      should_filter ||= receiver.blocking?(status.thread.account) # to a user I blocked
     end
 
     should_filter
@@ -92,9 +94,9 @@ class FeedManager
     should_filter = receiver.blocking?(status.account)
 
     if status.reply? && !status.thread.account.nil?
-      should_filter = should_filter || receiver.blocking?(status.thread.account)
+      should_filter ||= receiver.blocking?(status.thread.account)
     elsif status.reblog?
-      should_filter = should_filter || receiver.blocking?(status.reblog.account)
+      should_filter ||= receiver.blocking?(status.reblog.account)
     end
 
     should_filter

app/lib/formatter.rb

+# frozen_string_literal: true
+
 require 'singleton'
 
 class Formatter
@@ -17,7 +19,7 @@ class Formatter
     html = link_mentions(html, status.mentions)
     html = link_hashtags(html)
 
-    html.html_safe
+    html.html_safe # rubocop:disable Rails/OutputSafety
   end
 
   def reformat(html)
@@ -30,7 +32,7 @@ class Formatter