lsコマンドをクラス化

08.ls_object/base_view.rb

@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+class BaseView
+  def initialize(file_names)
+    @file_names = file_names
+    @file_infos = file_names.map do |file_name|
+      File.lstat(file_name)
+    end
+  end
+
+  def render
+    raise NotImplementedError, 'renderはサブクラスで定義する'
+  end
+end

08.ls_object/column_view.rb

@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+require_relative 'base_view'
+
+class ColumnView < BaseView
+  def initialize(file_names, columns = 3)
+    super(file_names)
+    @columns = columns
+  end
+
+  def render
+    max_len = @file_names.map(&:length).max
+    rows = display_rows(@file_names)
+
+    rows.times do |row_index|
+      @columns.times do
+        break if row_index > @file_names.size
+
+        file = @file_names[row_index]
+        print file.ljust(max_len).concat("\t") unless file.nil?
+        row_index += rows
+      end
+      print "\n"
+    end
+  end
+
+  def display_rows(list)
+    (list.size.to_r / @columns.to_r).to_f.ceil
+  end
+end

08.ls_object/list_view.rb

@@ -0,0 +1,77 @@
+# frozen_string_literal: true
+
+require 'etc'
+require_relative 'base_view'
+
+class ListView < BaseView
+  FILE_TYPE_STR = {
+    'file' => '-',
+    'blockSpecial' => 'b',
+    'characterSpecial' => 'c',
+    'directory' => 'd',
+    'link' => 'l',
+    'fifo' => 'p',
+    'socket' => 's',
+    'unknown' => '?'
+  }.freeze
+
+  PERMISSION_STR = {
+    0 => '-',
+    4 => 'r',
+    2 => 'w',
+    1 => 'x'
+  }.freeze
+
+  def render
+    display_file_infos = display_file_info
+    row_max_len = row_max_lenght(display_file_infos)
+    puts "total #{display_file_infos.map { |v| v[:blocks] }.sum}"
+    display_file_infos.each do |file|
+      print file[:type].rjust(row_max_len[:type])
+      print "#{file[:permission].rjust(row_max_len[:permission])}  "
+      print "#{file[:hard_link].rjust(row_max_len[:hard_link])} "
+      print "#{file[:owner].ljust(row_max_len[:owner])}  "
+      print "#{file[:group].ljust(row_max_len[:group])}  "
+      print "#{file[:file_size].to_s.rjust(row_max_len[:file_size])} "
+      print "#{file[:timestamp].rjust(row_max_len[:timestamp])} "
+      print "#{file[:file_name]} "
+      print " -> #{File.readlink(file[:file_name])}" if file[:file_name] == 'l'
+      print "\n"
+    end
+  end
+
+  def display_file_info
+    @file_names.map do |file_name|
+      stat = File.lstat(file_name)
+      display = {
+        file_name: file_name,
+        type: FILE_TYPE_STR[stat.ftype],
+        permission: print_permission(stat.mode, PERMISSION_STR),
+        hard_link: stat.nlink.to_s,
+        owner: Etc.getpwuid(stat.uid).name,
+        group: Etc.getgrgid(stat.gid).name,
+        file_size: stat.size,
+        timestamp: stat.mtime.strftime('%_m %_d %H:%M'),
+        blocks: stat.blocks
+      }
+      display
+    end
+  end
+
+  def row_max_lenght(display_file_infos)
+    max_len = Hash.new(0)
+    display_file_infos.each do |item|
+      item.each do |key, value|
+        max_len[key] = [max_len[key], value.to_s.length].max
+      end
+    end
+    max_len
+  end
+
+  def print_permission(mode, permission_str)
+    # 0100744 -> 774
+    mode.to_s(8)[-3, 3].split('').map do |v|
+      2.downto(0).map { |count| permission_str[v.to_i & (1 << count)] }.join
+    end.join
+  end
+end

08.ls_object/ls.rb

@@ -0,0 +1,8 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+require_relative 'option'
+require_relative 'ls_command'
+
+options = Option.new(ARGV)
+LsCommand.new.run(options)

08.ls_object/ls_command.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+require_relative 'list_view'
+require_relative 'column_view'
+
+class LsCommand
+  def run(options)
+    file_names = target_files(options)
+    file_names.reverse! if options.reverse_order
+
+    view = options.list_mode ? ListView.new(file_names) : ColumnView.new(file_names, 3)
+    view.render
+  end
+
+  def target_files(options)
+    flag = 0
+    flag = File::FNM_DOTMATCH if options.include_dotfiles
+
+    Dir.glob('*', flag)
+  end
+end

08.ls_object/option.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class Option
+  attr_reader :include_dotfiles, :reverse_order, :list_mode
+
+  def initialize(argv)
+    @include_dotfiles, @reverse_order, @list_mode = %w[a r l].map do |opt|
+      argv.any? { |v| v.start_with?('-') && v.include?(opt) }
+    end
+  end
+end