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#!/usr/local/bin/ruby
#
#   save this file in your $RUBY_LIB/site_ruby/1.8/irb/ext/save-history.rb
#   if you installed your ruby via macports, that'd be
#   /opt/local/lib/ruby/site_ruby/1.8/irb/ext/save-history.rb
#
#   souped up version of:
#   save-history.rb - 
#     $Release Version: 0.9.5$
#     $Revision: 11708 $
#     $Date: 2007-02-13 08:01:19 +0900 (Tue, 13 Feb 2007) $
#     by Keiju ISHITSUKAkeiju@ruby-lang.org)
#
# --
#
#   
#

require "readline"

module IRB
  module HistorySavingAbility
    @RCS_ID='-$Id: save-history.rb 11708 2007-02-12 23:01:19Z shyouhei $-'
  end

  class Context
    def init_save_history
      unless (class<<@io;self;end).include?(HistorySavingAbility)
  @io.extend(HistorySavingAbility)
      end
    end

    def save_history
      IRB.conf[:SAVE_HISTORY]
    end

    def save_history=(val)
      IRB.conf[:SAVE_HISTORY] = val
      if val
  main_context = IRB.conf[:MAIN_CONTEXT]
  main_context = self unless main_context
  main_context.init_save_history
      end
    end

    def history_file
      IRB.conf[:HISTORY_FILE]
    end

    def history_file=(hist)
      IRB.conf[:HISTORY_FILE] = hist
    end
  end

  module HistorySavingAbility
    include Readline

    # file should be a valid file_path to the history file
    # number_of_lines should be an Integer with the number of history lines to save
    def self.exit(file, number_of_lines, history, erasedups)
      if number_of_lines && number_of_lines > 0 then
        path = File.expand_path(file)
        File.open(path, 'w') do |f|
          history = history.reverse.uniq.reverse if erasedups
          # Instead of hist[-num..-1] || hist, we can just use Array#last
          f.puts(history.last(number_of_lines))
        end
      end
    end

    def HistorySavingAbility.extended(obj)
      # A finalizer is NOT guaranteed to run, bad choice for history saving
      # mechanism
      Kernel.at_exit do
        begin
          HistorySavingAbility.exit(
            IRB.conf[:HISTORY_FILE] || IRB.rc_file("_history"),
            IRB.conf[:SAVE_HISTORY].to_i,
            HISTORY.to_a,
            IRB.conf[:HISTORY_NO_DUPS]
          )
        rescue
          puts $!, *$!.backtrace
          raise
        end
      end
      obj.load_history
      obj
    end

    def load_history
      hist = IRB.conf[:HISTORY_FILE]
      hist = IRB.rc_file("_history") unless hist
      File.foreach(hist) do |line| HISTORY << line.chomp end
    rescue Errno::ENOENT # history file doesn't yet exist
    end
  end
end