refactored common diff code in shell

lib/thor/shell/color.rb

@@ -1,11 +1,14 @@
 require_relative "basic"
+require_relative "diff_lines"
 
 class Thor
   module Shell
     # Inherit from Thor::Shell::Basic and add set_color behavior. Check
     # Thor::Shell::Basic to see all available methods.
     #
     class Color < Basic
+      include DiffLines
+
       # Embed in a String to clear all previous ANSI sequences.
       CLEAR      = "\e[0m"
       # The start of an ANSI bold sequence.
@@ -108,50 +111,24 @@ def are_colors_disabled?
         !ENV['NO_COLOR'].nil? && !ENV['NO_COLOR'].empty?
       end
 
-      # Overwrite show_diff to show diff with colors if Diff::LCS is
-      # available.
-      #
-      def show_diff(destination, content) #:nodoc:
-        if diff_lcs_loaded? && ENV["THOR_DIFF"].nil? && ENV["RAILS_DIFF"].nil?
-          actual  = File.binread(destination).to_s.split("\n")
-          content = content.to_s.split("\n")
-
-          Diff::LCS.sdiff(actual, content).each do |diff|
-            output_diff_line(diff)
-          end
-        else
-          super
+        # Overwrite show_diff to show diff with colors if Diff::LCS is
+        # available.
+        #
+        def show_diff(destination, content) #:nodoc:
+          show_diff_common(destination, content)
         end
-      end
 
-      def output_diff_line(diff) #:nodoc:
-        case diff.action
-        when "-"
-          say "- #{diff.old_element.chomp}", :red, true
-        when "+"
-          say "+ #{diff.new_element.chomp}", :green, true
-        when "!"
-          say "- #{diff.old_element.chomp}", :red, true
-          say "+ #{diff.new_element.chomp}", :green, true
-        else
-          say "  #{diff.old_element.chomp}", nil, true
+        def output_diff_line(diff)
+          output_diff_line_common(diff)
         end
-      end
-
-      # Check if Diff::LCS is loaded. If it is, use it to create pretty output
-      # for diff.
-      #
-      def diff_lcs_loaded? #:nodoc:
-        return true if defined?(Diff::LCS)
-        return @diff_lcs_loaded unless @diff_lcs_loaded.nil?
 
-        @diff_lcs_loaded = begin
-          require "diff/lcs"
-          true
-        rescue LoadError
-          false
+        # Check if Diff::LCS is loaded. If it is, use it to create pretty output
+        # for diff.
+        #
+        def diff_lcs_loaded? #:nodoc:
+          diff_lcs_loaded_common?
         end
-      end
+
     end
   end
 end

lib/thor/shell/diff_lines.rb

@@ -0,0 +1,43 @@
+module DiffLines
+
+  protected
+  def show_diff_common(destination, content) #:nodoc:
+    if diff_lcs_loaded? && ENV['THOR_DIFF'].nil? && ENV['RAILS_DIFF'].nil?
+      actual  = File.binread(destination).to_s.split("\n")
+      content = content.to_s.split("\n")
+
+      Diff::LCS.sdiff(actual, content).each do |diff|
+        output_diff_line(diff)
+      end
+    else
+      super
+    end
+  end
+
+  def output_diff_line_common(diff) #:nodoc:
+    case diff.action
+    when '-'
+      say "- #{diff.old_element.chomp}", :red, true
+    when '+'
+      say "+ #{diff.new_element.chomp}", :green, true
+    when '!'
+      say "- #{diff.old_element.chomp}", :red, true
+      say "+ #{diff.new_element.chomp}", :green, true
+    else
+      say "  #{diff.old_element.chomp}", nil, true
+    end
+  end
+
+  def diff_lcs_loaded_common? #:nodoc:
+    return true  if defined?(Diff::LCS)
+    return @diff_lcs_loaded unless @diff_lcs_loaded.nil?
+
+    @diff_lcs_loaded = begin
+      require 'diff/lcs'
+      true
+    rescue LoadError
+      false
+    end
+  end
+
+end

lib/thor/shell/html.rb

@@ -6,6 +6,8 @@ module Shell
     # Thor::Shell::Basic to see all available methods.
     #
     class HTML < Basic
+      include DiffLines
+
       # The start of an HTML bold sequence.
       BOLD       = "font-weight: bold"
 
@@ -77,50 +79,24 @@ def can_display_colors?
         true
       end
 
-      # Overwrite show_diff to show diff with colors if Diff::LCS is
-      # available.
-      #
-      def show_diff(destination, content) #:nodoc:
-        if diff_lcs_loaded? && ENV["THOR_DIFF"].nil? && ENV["RAILS_DIFF"].nil?
-          actual  = File.binread(destination).to_s.split("\n")
-          content = content.to_s.split("\n")
-
-          Diff::LCS.sdiff(actual, content).each do |diff|
-            output_diff_line(diff)
-          end
-        else
-          super
+        # Overwrite show_diff to show diff with colors if Diff::LCS is
+        # available.
+        #
+        def show_diff(destination, content) #:nodoc:
+          show_diff_common(destination, content)
         end
-      end
 
-      def output_diff_line(diff) #:nodoc:
-        case diff.action
-        when "-"
-          say "- #{diff.old_element.chomp}", :red, true
-        when "+"
-          say "+ #{diff.new_element.chomp}", :green, true
-        when "!"
-          say "- #{diff.old_element.chomp}", :red, true
-          say "+ #{diff.new_element.chomp}", :green, true
-        else
-          say "  #{diff.old_element.chomp}", nil, true
+        def output_diff_line(diff) #:nodoc:
+          output_diff_line_common(diff)
         end
-      end
-
-      # Check if Diff::LCS is loaded. If it is, use it to create pretty output
-      # for diff.
-      #
-      def diff_lcs_loaded? #:nodoc:
-        return true if defined?(Diff::LCS)
-        return @diff_lcs_loaded unless @diff_lcs_loaded.nil?
 
-        @diff_lcs_loaded = begin
-          require "diff/lcs"
-          true
-        rescue LoadError
-          false
+        # Check if Diff::LCS is loaded. If it is, use it to create pretty output
+        # for diff.
+        #
+        def diff_lcs_loaded? #:nodoc:
+          diff_lcs_loaded_common?
         end
-      end
+
     end
   end
 end