[ruby/irb] Powerup show_source by enabling RubyVM.keep_script_lines

(https://github.com/ruby/irb/pull/862)

* Powerup show_source by enabling RubyVM.keep_script_lines

* Add file_content field to avoid reading file twice while show_source

* Change path passed to eval, don't change irb_path.

* Encapsulate source coloring logic and binary file check insode class Source

* Add edit command testcase when irb_path does not exist

* Memoize irb_path existence to reduce file existence check calculating eval_path

https://github.com/ruby/irb/commit/239683a937

2 files changed, 18 insertions, 15 deletions

diff --git a/lib/irb/cmd/edit.rb b/lib/irb/cmd/edit.rb
index 69606beea0..2f89f83ecc 100644
--- a/lib/irb/cmd/edit.rb
+++ b/lib/irb/cmd/edit.rb
@@ -24,11 +24,9 @@ module IRB
       def execute(*args)
         path = args.first
 
-        if path.nil? && (irb_path = @irb_context.irb_path)
-          path = irb_path
-        end
-
-        if !File.exist?(path)
+        if path.nil?
+          path = @irb_context.irb_path
+        elsif !File.exist?(path)
           source =
             begin
               SourceFinder.new(@irb_context).find_source(path)
@@ -37,14 +35,16 @@ module IRB
               # in this case, we should just ignore the error
             end
 
-          if source
+          if source&.file_exist? && !source.binary_file?
             path = source.file
-          else
-            puts "Can not find file: #{path}"
-            return
           end
         end
 
+        unless File.exist?(path)
+          puts "Can not find file: #{path}"
+          return
+        end
+
         if editor = (ENV['VISUAL'] || ENV['EDITOR'])
           puts "command: '#{editor}'"
           puts "   path: #{path}"
diff --git a/lib/irb/cmd/show_source.rb b/lib/irb/cmd/show_source.rb
index 826cb11ed2..cd07de3e90 100644
--- a/lib/irb/cmd/show_source.rb
+++ b/lib/irb/cmd/show_source.rb
@@ -45,15 +45,18 @@ module IRB
       private
 
       def show_source(source)
-        file_content = IRB::Color.colorize_code(File.read(source.file))
-        code = file_content.lines[(source.first_line - 1)...source.last_line].join
-        content = <<~CONTENT
+        if source.binary_file?
+          content = "\n#{bold('Defined in binary file')}: #{source.file}\n\n"
+        else
+          code = source.colorized_content || 'Source not available'
+          content = <<~CONTENT
 
-          #{bold("From")}: #{source.file}:#{source.first_line}
+            #{bold("From")}: #{source.file}:#{source.line}
 
-          #{code}
-        CONTENT
+            #{code.chomp}
 
+          CONTENT
+        end
         Pager.page_content(content)
       end