From 87b6e79952b90daddae5078581af971c9ca839a7 Mon Sep 17 00:00:00 2001
From: Alex Ling <hkalexling@gmail.com>
Date: Tue, 21 Jul 2020 12:33:50 +0000
Subject: [PATCH] Use macro to DRY the `self.default` method

---
 src/library/library.cr     | 7 +------
 src/logger.cr              | 7 +------
 src/mangadex/api.cr        | 7 +------
 src/mangadex/downloader.cr | 7 +------
 src/plugin/downloader.cr   | 8 +-------
 src/queue.cr               | 7 +------
 src/server.cr              | 7 +------
 src/storage.cr             | 7 +------
 src/util/util.cr           | 9 +++++++++
 9 files changed, 17 insertions(+), 49 deletions(-)

diff --git a/src/library/library.cr b/src/library/library.cr
index a062105..cba0421 100644
--- a/src/library/library.cr
+++ b/src/library/library.cr
@@ -2,12 +2,7 @@ class Library
   property dir : String, title_ids : Array(String), scan_interval : Int32,
     title_hash : Hash(String, Title)
 
-  def self.default : self
-    unless @@default
-      @@default = new
-    end
-    @@default.not_nil!
-  end
+  use_default
 
   def initialize
     register_mime_types
diff --git a/src/logger.cr b/src/logger.cr
index 8c049ed..3777e9c 100644
--- a/src/logger.cr
+++ b/src/logger.cr
@@ -8,12 +8,7 @@ class Logger
 
   @@severity : Log::Severity = :info
 
-  def self.default : self
-    unless @@default
-      @@default = new
-    end
-    @@default.not_nil!
-  end
+  use_default
 
   def initialize
     level = Config.current.log_level
diff --git a/src/mangadex/api.cr b/src/mangadex/api.cr
index 30e5c69..fd7b06e 100644
--- a/src/mangadex/api.cr
+++ b/src/mangadex/api.cr
@@ -131,12 +131,7 @@ module MangaDex
   end
 
   class API
-    def self.default : self
-      unless @@default
-        @@default = new
-      end
-      @@default.not_nil!
-    end
+    use_default
 
     def initialize
       @base_url = Config.current.mangadex["api_url"].to_s ||
diff --git a/src/mangadex/downloader.cr b/src/mangadex/downloader.cr
index 9b0f232..3541d51 100644
--- a/src/mangadex/downloader.cr
+++ b/src/mangadex/downloader.cr
@@ -7,12 +7,7 @@ module MangaDex
       .to_i32
     @retries : Int32 = Config.current.mangadex["download_retries"].to_i32
 
-    def self.default : self
-      unless @@default
-        @@default = new
-      end
-      @@default.not_nil!
-    end
+    use_default
 
     def initialize
       super
diff --git a/src/plugin/downloader.cr b/src/plugin/downloader.cr
index 9b55fd4..25dca6d 100644
--- a/src/plugin/downloader.cr
+++ b/src/plugin/downloader.cr
@@ -1,12 +1,6 @@
 class Plugin
   class Downloader < Queue::Downloader
-
-    def self.default : self
-      unless @@default
-        @@default = new
-      end
-      @@default.not_nil!
-    end
+    use_default
 
     def initialize
       super
diff --git a/src/queue.cr b/src/queue.cr
index 3235fc3..a4dbcb2 100644
--- a/src/queue.cr
+++ b/src/queue.cr
@@ -92,12 +92,7 @@ class Queue
   @downloaders = [] of Downloader
   @paused = false
 
-  def self.default : self
-    unless @@default
-      @@default = new
-    end
-    @@default.not_nil!
-  end
+  use_default
 
   def initialize(db_path : String? = nil)
     @path = db_path || Config.current.mangadex["download_queue_db_path"].to_s
diff --git a/src/server.cr b/src/server.cr
index fc4f7ae..380f4b3 100644
--- a/src/server.cr
+++ b/src/server.cr
@@ -10,12 +10,7 @@ class Context
   property storage : Storage
   property queue : Queue
 
-  def self.default : self
-    unless @@default
-      @@default = new
-    end
-    @@default.not_nil!
-  end
+  use_default
 
   def initialize
     @storage = Storage.default
diff --git a/src/storage.cr b/src/storage.cr
index a9fb144..2c42719 100644
--- a/src/storage.cr
+++ b/src/storage.cr
@@ -21,12 +21,7 @@ class Storage
     id: String,
     is_title: Bool)
 
-  def self.default : self
-    unless @@default
-      @@default = new
-    end
-    @@default.not_nil!
-  end
+  use_default
 
   def initialize(db_path : String? = nil, init_user = true, *,
                  @auto_close = true)
diff --git a/src/util/util.cr b/src/util/util.cr
index 26e0750..b26979a 100644
--- a/src/util/util.cr
+++ b/src/util/util.cr
@@ -45,3 +45,12 @@ struct Nil
     other
   end
 end
+
+macro use_default
+  def self.default : self
+    unless @@default
+      @@default = new
+    end
+    @@default.not_nil!
+  end
+end