ruby-ls solution

samples/part1/bin/ruby-ls

@@ -1,4 +1,7 @@
 #!/usr/bin/env ruby
 
-## FIXME: Replace this code with a pure Ruby clone of the ls utility
-system("ls", *ARGV)
+require 'optparse'
+require 'etc'
+require_relative '../lib/ruby-ls'
+
+RubyLS::Application.new(ARGV).run

samples/part1/lib/ruby-ls.rb

@@ -0,0 +1,2 @@
+require_relative "ruby-ls/application"
+require_relative "ruby-ls/display"

samples/part1/lib/ruby-ls/application.rb

@@ -0,0 +1,30 @@
+module RubyLS
+  class Application
+    def initialize(argv)
+      @params, @dirs = parse_options(argv)
+      @display       = RubyLS::Display.new(@params)
+    end
+
+    def run
+      @display.render(@dirs)
+    end
+
+    def parse_options(argv)
+      params = {}
+      parser = OptionParser.new
+
+      parser.on("-l") { params[:display_format] = :long }
+      parser.on("-a") { params[:show_hidden]    = true }
+
+      begin
+        dirs = parser.parse(argv)
+      rescue OptionParser::InvalidOption
+        $stderr.puts "ls: illegal option -- #{argv[0][1]}"
+        $stderr.puts "usage: ls [-ABCFGHLOPRSTUWabcdefghiklmnopqrstuwx1] [file ...]"
+        exit(1)
+      end
+
+      [params, dirs]
+    end
+  end
+end

samples/part1/lib/ruby-ls/display.rb

@@ -0,0 +1,110 @@
+module RubyLS
+  class Display
+    attr_reader :display_format, :show_hidden, :glob, :files
+
+    def initialize(params)
+      @display_format = params[:display_format]
+      @show_hidden    = params[:show_hidden]
+      @glob = false
+    end
+
+    def render(data)
+      report = ''
+
+      if data.empty?
+        @files = get_directory(Dir.pwd)
+      else
+        @files = []
+        data.each do |dir|
+          @files.push(*get_directory(dir))
+        end
+      end
+
+      glob = @files.none? { |d| File.directory?(d) }
+
+      if display_format
+        block_total = 0
+        @files.each do |file|
+          block_total += File.stat(file).blocks
+          report << build_long_report(file)
+        end
+        puts "total #{block_total}" unless glob
+      else
+        @files.each do |file|
+          report << "#{file}\n"
+        end
+      end
+      puts report
+    end
+
+    def get_directory(dir)
+      if !File.file?(dir) && !File.directory?(dir)
+        $stderr.puts "ls: #{dir}: No such file or directory"
+        exit(1)
+      end
+
+      if Dir.exists?(dir)
+        Dir.chdir(dir)
+        files = show_hidden == true ? Dir.entries('.') : Dir.glob('*')
+      else
+        files = Dir.glob(dir)
+      end
+    end
+
+    def padding(files)
+      files.map { |f| File.stat(f).size.to_s.size }.max 
+    end
+
+    def build_long_report(dir)
+      output = ''
+
+      uid = File.stat(dir).uid
+      gid = File.stat(dir).gid
+      mode = get_mode_string(dir)
+      links = File.stat(dir).nlink.to_s
+      size = File.stat(dir).size.to_s
+      mtime = File.stat(dir).mtime
+      mtime = mtime.strftime("%b %e %H:%M")
+      uname = Etc.getpwuid(uid).name
+      gname = Etc.getgrgid(gid).name
+      output << mode + '  '
+      output << links + ' '
+      output << uname + '  '
+      output << gname + '  '
+      output << size.rjust(padding(files)) + ' '
+      output << mtime + ' '
+      output << dir
+      output << "\n"
+    end
+
+    def get_mode_string(file)
+      read_idx = [0, 3, 6]
+      write_idx = [1, 4, 7]
+      exe_idx = [2, 5, 8]
+      mode_string = ''
+
+      if Dir.exists?(file)
+        mode_string << 'd'
+      else
+        mode_string << '-'
+      end
+
+      mode = File.stat(file).mode
+      mode_bits = mode.to_s(2).split(//).last(9)
+      mode_bits.each_with_index do |b, i|
+        if b == "1"
+          if read_idx.include?(i)
+            mode_string << 'r'
+          elsif write_idx.include?(i)
+            mode_string << 'w'
+          elsif exe_idx.include?(i)
+            mode_string << 'x'
+          end
+        else
+          mode_string <<  '-'
+        end
+      end
+      mode_string
+    end
+  end
+end