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