オブジェクト指向版lsコマンドを作ってみた

08.ls_object/.rubocop.yml

@@ -0,0 +1,11 @@
+inherit_gem:
+  rubocop-fjord:
+    - "config/rubocop.yml"
+
+AllCops:
+  Exclude:
+    - test/fixtures/**/*
+
+Metrics/MethodLength:
+  Exclude:
+    - test/**/*

08.ls_object/Rakefile

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+require 'rake/testtask'
+
+Rake::TestTask.new do |t|
+  t.pattern = 'test/**/*_test.rb'
+end
+
+task default: :test

08.ls_object/bin/ls

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+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+require_relative '../lib/ls_app'
+
+LsApp.main

08.ls_object/lib/ls_app.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+require_relative 'params'
+require_relative 'models/ls_file'
+require_relative 'views/short_format'
+require_relative 'views/long_format'
+
+module LsApp
+  def self.main(argv = ARGV)
+    params = Params.new(argv)
+    ls_files = LsFile.all(params)
+    if params.long_format?
+      puts LongFormat.new(ls_files).render
+    else
+      puts ShortFormat.new(ls_files).render
+    end
+  end
+end

08.ls_object/lib/models/ls_file.rb

@@ -0,0 +1,65 @@
+# frozen_string_literal: true
+
+require 'etc'
+require 'pathname'
+
+class LsFile
+  def self.all(params)
+    pattern = File.join(params.target_directory, '*')
+    flag = params.dot_match? ? File::FNM_DOTMATCH : 0
+    paths = Dir.glob(pattern, flag)
+    paths << File.join(params.target_directory, '..') if params.dot_match?
+    sorted_paths = params.reverse? ? paths.sort.reverse : paths.sort
+    sorted_paths.map { |path| LsFile.new(path) }
+  end
+
+  def initialize(path)
+    @pathname = Pathname.new(path)
+  end
+
+  def name
+    @pathname.basename.to_s
+  end
+
+  def block_size
+    file_stat.blocks
+  end
+
+  def file_type
+    file_stat.ftype
+  end
+
+  def permission
+    file_stat.mode.to_s(8)[-3..]
+  end
+
+  def link_count
+    @pathname.directory? ? @pathname.entries.size : 1
+  end
+
+  def owner_name
+    Etc.getpwuid(file_stat.uid).name
+  end
+
+  def group_name
+    Etc.getgrgid(file_stat.gid).name
+  end
+
+  def bytesize
+    @pathname.size
+  end
+
+  def mtime
+    @pathname.mtime
+  end
+
+  def to_s
+    name
+  end
+
+  private
+
+  def file_stat
+    @pathname.stat
+  end
+end

08.ls_object/lib/params.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require 'optparse'
+
+class Params
+  attr_reader :target_directory
+
+  def initialize(argv)
+    opt = OptionParser.new
+
+    @params = {}
+    opt.on('-a') { @params[:a] = true }
+    opt.on('-l') { @params[:l] = true }
+    opt.on('-r') { @params[:r] = true }
+
+    paths = opt.parse!(argv)
+    @target_directory = paths[0] || Dir.getwd
+  end
+
+  def dot_match?
+    !!@params[:a]
+  end
+
+  def reverse?
+    !!@params[:r]
+  end
+
+  def long_format?
+    !!@params[:l]
+  end
+end

08.ls_object/lib/views/long_format.rb

@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+class LongFormat
+  FILE_TYPE_TABLE = {
+    'file' => '-',
+    'directory' => 'd'
+  }.freeze
+
+  PERMISSION_TABLE = {
+    '1' => '--x',
+    '2' => '-w-',
+    '3' => '-wx',
+    '4' => 'r--',
+    '5' => 'r-x',
+    '6' => 'rw-',
+    '7' => 'rwx'
+  }.freeze
+
+  def initialize(ls_files)
+    @ls_files = ls_files
+  end
+
+  def render
+    total = @ls_files.sum(&:block_size)
+    header = "total #{total}"
+    widths = calc_widths
+    body = @ls_files.map { |ls_file| format_row(ls_file, widths) }
+    [header, *body].join("\n")
+  end
+
+  private
+
+  def format_row(ls_file, widths)
+    [
+      "#{format_mode(ls_file)} ",
+      ls_file.link_count.to_s.rjust(widths[:link_count]),
+      "#{ls_file.owner_name.ljust(widths[:owner_name])} ",
+      "#{ls_file.group_name.ljust(widths[:group_name])} ",
+      ls_file.bytesize.to_s.rjust(widths[:bytesize]),
+      ls_file.mtime.strftime('%b %d %H:%M'),
+      ls_file.name
+    ].join(' ')
+  end
+
+  def format_mode(ls_file)
+    file_type = FILE_TYPE_TABLE[ls_file.file_type]
+    permission = ls_file.permission.each_char.map { |c| PERMISSION_TABLE[c] }.join
+    file_type + permission
+  end
+
+  def calc_widths
+    widths = Hash.new { |h, k| h[k] = [] }
+    @ls_files.each do |ls_file|
+      widths[:link_count] << ls_file.link_count.to_s.size
+      widths[:owner_name] << ls_file.owner_name.size
+      widths[:group_name] << ls_file.group_name.size
+      widths[:bytesize] << ls_file.bytesize.to_s.size
+    end
+    widths.transform_values(&:max)
+  end
+end

08.ls_object/lib/views/short_format.rb

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+# frozen_string_literal: true
+
+class ShortFormat
+  COLUMN_COUNT = 3
+
+  def initialize(ls_files)
+    @ls_files = ls_files
+  end
+
+  def render
+    column_width = @ls_files.map { |ls_file| ls_file.name.size }.max
+    ls_file_table = generate_ls_file_table
+    ls_file_table.map { |row| format_row(row, column_width) }.join("\n")
+  end
+
+  private
+
+  def format_row(row, column_width)
+    row.map { |ls_file| ls_file.name.ljust(column_width) }.join(' ').strip
+  end
+
+  def generate_ls_file_table
+    row_count = (@ls_files.size.to_f / COLUMN_COUNT).ceil
+    ls_file_table = @ls_files.each_slice(row_count).to_a
+    blank_count = row_count - ls_file_table[-1].size
+    blank_ls_files = Array.new(blank_count, LsFile.new(''))
+    ls_file_table[-1].push(*blank_ls_files)
+    ls_file_table.transpose
+  end
+end

08.ls_object/test/ls_app_test.rb

@@ -0,0 +1,74 @@
+# frozen_string_literal: true
+
+require 'minitest/autorun'
+require_relative '../lib/ls_app'
+
+class LsAppTest < Minitest::Test
+  def setup
+    @directory = Pathname.new(__dir__).join('fixtures/config')
+  end
+
+  def test_long_format
+    expected = <<~TEXT
+      total 80
+      drwxr-xr-x  15 jnito  staff   480 Apr 29 12:20 .
+      drwxr-xr-x   4 jnito  staff   128 Apr 29 12:37 ..
+      -rw-r--r--   1 jnito  staff   740 Mar 20 17:45 application.rb
+      -rw-r--r--   1 jnito  staff   207 Mar 20 17:45 boot.rb
+      -rw-r--r--   1 jnito  staff   193 Mar 20 17:45 cable.yml
+      -rw-r--r--   1 jnito  staff   464 Mar 20 17:45 credentials.yml.enc
+      -rw-r--r--   1 jnito  staff   620 Mar 20 17:45 database.yml
+      -rw-r--r--   1 jnito  staff   128 Mar 20 17:45 environment.rb
+      drwxr-xr-x   5 jnito  staff   160 Mar 20 17:45 environments
+      -rw-r--r--   1 jnito  staff   381 Apr 10 07:35 importmap.rb
+      drwxr-xr-x   9 jnito  staff   288 Mar 20 17:45 initializers
+      drwxr-xr-x   5 jnito  staff   160 Mar 20 17:45 locales
+      -rw-r--r--   1 jnito  staff  1792 Mar 20 17:45 puma.rb
+      -rw-r--r--   1 jnito  staff   322 Mar 20 17:45 routes.rb
+      -rw-r--r--   1 jnito  staff  1152 Mar 20 17:45 storage.yml
+    TEXT
+    argv = ['-al', @directory]
+    assert_output(expected) do
+      LsApp.main(argv)
+    end
+  end
+
+  def test_short_format_without_options
+    expected = <<~TEXT
+      application.rb      environment.rb      puma.rb
+      boot.rb             environments        routes.rb
+      cable.yml           importmap.rb        storage.yml
+      credentials.yml.enc initializers
+      database.yml        locales
+    TEXT
+    argv = [@directory]
+    assert_output(expected) do
+      LsApp.main(argv)
+    end
+  end
+
+  def test_short_format_with_a_and_r_options
+    expected = <<~TEXT
+      storage.yml         importmap.rb        cable.yml
+      routes.rb           environments        boot.rb
+      puma.rb             environment.rb      application.rb
+      locales             database.yml        ..
+      initializers        credentials.yml.enc .
+    TEXT
+    argv = ['-ar', @directory]
+    assert_output(expected) do
+      LsApp.main(argv)
+    end
+  end
+
+  def test_short_format_without_args
+    expected = <<~TEXT
+      Rakefile lib
+      bin      test
+    TEXT
+    argv = []
+    assert_output(expected) do
+      LsApp.main(argv)
+    end
+  end
+end