pdumpfs

#! /usr/bin/env ruby
#
#  pdumpfs - a daily backup system similar to Plan9's dumpfs.
#
#  DESCRIPTION:
#
#    pdumpfs is a simple daily backup system similar to
#    Plan9's dumpfs which preserves every daily snapshot.
#    You can access the past snapshots at any time for
#    retrieving a certain day's file.  Let's backup your home
#    directory with pdumpfs!
#
#    pdumpfs constructs the snapshot YYYY/MM/DD in the
#    destination directory. All source files are copied to
#    the snapshot directory for the first time. On and after
#    the second time, pdumpfs copies only updated or newly
#    created files and stores unchanged files as hard links
#    to the files of the previous day's snapshot for saving a
#    disk space.
#
#  USAGE:
#
#    % pdumpfs <source directory> <destination directory>
#             [<destination basename>]
#
#  SAMPLE CRONTAB ENTRY:
#
#    00 05 * * * pdumpfs /home/USER /backup >/dev/null 2>&1
#
#  BUGS:
#
#    pdumpfs can handle only normal files, directories, and
#    symbolic links.
#
#
# Copyright (C) 2001-2004 Satoru Takabayashi <satoru@namazu.org>
#     All rights reserved.
#     This is free software with ABSOLUTELY NO WARRANTY.
#
# You can redistribute it and/or modify it under the terms of
# the GNU General Public License version 2.
#
#
# Win32 ported by Yasuhiro Morioka <yasuhiro.morioka@k5.dion.ne.jp>
# 2003/02/01
#
# --exclude-* support by Takeshi Komiya <katsuwo@monochrome.jp>
#

require 'find'
require 'fileutils'
require 'getoptlong'
require 'date'

class File
  def self.real_file? (path)
    File.file?(path) and not File.symlink?(path)
  end

  def self.anything_exist? (path)
    File.exist?(path) or File.symlink?(path)
  end

  def self.real_directory? (path)
    File.directory?(path) and not File.symlink?(path)
  end

  def self.force_symlink (src, dest)
    begin
      File.unlink(dest) if File.anything_exist?(dest)
      File.symlink(src, dest)
    rescue NotImplementedError # for Windows
    end
  end

  def self.force_link (src, dest)
    File.unlink(dest) if File.anything_exist?(dest)
    File.link(src, dest)
  end

  def self.readable_file? (path)
    File.file?(path) and File.readable?(path)
  end

  def self.split_all (path)
    parts = []
    while true
      dirname, basename = File.split(path)
      break if path == dirname
      parts.unshift(basename) unless basename == "."
      path = dirname
    end
    return parts
  end
end

def wprintf (format, *args)
  STDERR.printf("pdumpfs: " + format + "\n", *args)
end

def windows?
  /mswin32|cygwin|mingw|bccwin/.match(RUBY_PLATFORM)
end

if windows?
  require 'Win32API'
  require "win32ole"

  if RUBY_VERSION < "1.8.0"
    CreateHardLinkA = Win32API.new("kernel32", "CreateHardLinkA", "ppl", 'i')
    def File.link(l, t)
      result = CreateHardLinkA.call(t, l, 0)

      raise Errno::EACCES  if result == 0
    end
  end

  def expand_special_folders (dir)
    specials = %w[(?:AllUsers)?(?:Desktop|Programs|Start(?:Menu|up)) Favorites
                  Fonts MyDocuments NetHood PrintHood Recent SendTo Templates]

    pattern = Regexp.compile(sprintf('^@(%s)', specials.join('|')))

    dir.sub(pattern) do |match|
      WIN32OLE.new("WScript.Shell").SpecialFolders(match)
    end.tr('\\', File::SEPARATOR)
  end

  GetVolumeInformation = Win32API.new("kernel32", "GetVolumeInformation",
                                      "PPLPPPPL", "I")
  def get_filesystem_type (path)
    return nil unless(File.exist?(path))

    drive = File.expand_path(path)[0..2]
    buff = "\0" * 1024
    GetVolumeInformation.call(drive, nil, 0, nil, nil, nil, buff, 1024)

    buff.sub(/\000+/, '')
  end

  def ntfs? (dir)
    get_filesystem_type(dir) == "NTFS"
  end

  GetLocaltime = Win32API.new("kernel32", "GetLocalTime", "P", 'V')
  SystemTimeToFileTime = Win32API.new("kernel32", "SystemTimeToFileTime",
                                      "PP", 'I')
  def get_file_time (time)
    pSYSTEMTIME = ' ' * 2 * 8     # 2byte x 8
    pFILETIME = ' ' * 2 * 8       # 2byte x 8

    GetLocaltime.call(pSYSTEMTIME)
    t1 = pSYSTEMTIME.unpack("S8")
    t1[0..1] = time.year, time.month
    t1[3..6] = time.day, time.hour, time.min, time.sec

    SystemTimeToFileTime.call(t1.pack("S8"), pFILETIME)

    pFILETIME
  end

  GENERIC_WRITE   = 0x40000000
  OPEN_EXISTING = 3
  FILE_FLAG_BACKUP_SEMANTICS =  0x02000000

  class << File
    alias_method(:utime_orig, :utime)
  end

  CreateFile  = Win32API.new("kernel32", "CreateFileA",
                             "PLLLLLL", "L")
  SetFileTime = Win32API.new("kernel32", "SetFileTime", "LPPP", "I")
  CloseHandle = Win32API.new("kernel32", "CloseHandle", "L", "I")

  def File.utime (a, m, dir)
    File.utime_orig(a, m, dir)  unless(File.directory?(dir))

    atime = get_file_time(a.dup.utc)
    mtime = get_file_time(m.dup.utc)

    hDir = CreateFile.Call(dir.dup, GENERIC_WRITE, 0, 0, OPEN_EXISTING,
                            FILE_FLAG_BACKUP_SEMANTICS, 0)
    SetFileTime.call(hDir, 0, atime, mtime)
    CloseHandle.Call(hDir)

    return 0
  end

  LOCALE_USER_DEFAULT    = 0x400
  LOCALE_SABBREVLANGNAME = 3
  LOCALE_USE_CP_ACP      = 0x40000000
  GetLocaleInfo = Win32API.new("kernel32", "GetLocaleInfo", "IIPI", "I")

  def get_locale_name
    locale_name = " " * 32
    status = GetLocaleInfo.call(LOCALE_USER_DEFAULT, 
                                LOCALE_SABBREVLANGNAME | LOCALE_USE_CP_ACP,
                                locale_name, 32)
    if status == 0
      return nil
    else
      return locale_name.split("\x00").first
    end
  end

  SW_HIDE                = 0
  SW_SHOWNORMAL          = 1

  ShellExecute      = Win32API.new("shell32",  "ShellExecute", "LPPPPL", 'L')
  LoadIcon          = Win32API.new("user32",   "LoadIcon", "II", "I")
  GetModuleFileName = Win32API.new("kernel32", "GetModuleFileName","IPI","I")

  def get_exe_file_name
    path = "\0" * 1024
    length = GetModuleFileName.call(0 ,path, path.length)
    return path[0, length].tr('\\', File::SEPARATOR)
  end

  def get_program_file_name
    exe_file_name = get_exe_file_name
    if File.basename(exe_file_name) == "ruby.exe"
      return File.expand_path($0).gsub('\\', File::SEPARATOR)
    else
      return exe_file_name
    end
  end

  def get_program_directory
    program_file_name = get_program_file_name
    return File.dirname(program_file_name)
  end

  def init
    locale_name = get_locale_name
    $KCODE = "SJIS" if locale_name == "JPN"
  end

  init
end

$vruby_libraries_loaded = false
begin
  require "vr/vrcontrol"
  require 'vr/vrcomctl'
  require "vr/vrlayout"
  require "vr/vrhandler"
  require "vr/vrtray"
  require 'vr/vrdialog'
  $vruby_libraries_loaded = true
rescue LoadError    => e
end

def has_vruby?
  $vruby_libraries_loaded
end

if has_vruby?
  require 'thread'

  def hour (sec)
    sec / 3600
  end

  def min (sec)
    sec % 3600 / 60
  end

  def sec (sec)
    sec % 60
  end

  module SWin
    class Window
      # FIXME: Very dirty way to tell the sizes of the fringes...
      def get_delta_xy
        move(0, 0, 500, 500)
        xx, yy, ww, hh = clientrect
        return self.w - ww, self.h - hh
      end
    end
  end

  module GetText
    def gettext (text)
      return text unless $catalog_messages
      return ($catalog_messages[text] or text)
    end
    alias :_ :gettext

    def load_catalog (filename)
      load(filename)
      $catalog_messages = Messages
    end
  end

  class TaskSchedulerDialog < VRModalDialog
    include VRGridLayoutManager
    include GetText

    GridWidth  = 24
    GridHeight = 7
    GridUnit   = 8
    def construct
      self.caption = _("Add to task scheduler")
      setDimension(GridWidth, GridHeight)
      s = WStyle::WS_TABSTOP
      
      addControl(VRStatic,   "hour_label",    _("Hour"),   1, 1, 7,  2)
      addControl(VRStatic,   "min_label",     _("Minute"), 9, 1, 7,  2)
      addControl(VRCombobox, "hour_combobox", "",          1, 3, 7, 40, s)
      addControl(VRCombobox, "min_combobox",  "",          9, 3, 7, 40, s)
      addControl(VRButton,   "set_button",    _("Add"),   17, 3, 6,  3, s)
      delta_x, delta_y = get_delta_xy
      self.move(200, 200, 
                GridWidth * GridUnit  + delta_x, 
                GridHeight * GridUnit + delta_y)
      24.times {|i| @hour_combobox.addString(sprintf("%02d", i)) }
      60.times {|i| @min_combobox.addString(sprintf("%02d", i)) }
      hour = Time.now.hour
      min  = Time.now.min
      @hour_combobox.select(hour)
      @min_combobox.select(min)
    end

    def set_button_clicked
      hour = @hour_combobox.selectedString.to_i
      min  = @min_combobox.selectedString.to_i
      close([hour, min])
    end
  end

  class VRMenuItem
    MF_ENABLED  = 0
    MF_GRAYED   = 1
    MF_DISABLED = 2
    MF_CHECKED  = 8

    def disable
      self.state |= MF_GRAYED
    end

    def enable
      self.state &= ~MF_GRAYED
    end
  end

  module PdumpfsForm
    include GetText

    include VRGridLayoutManager
    include VRMenuUseable
    include VRClosingSensitive
    include VRTrayiconFeasible
    include VRStatusbarDockable

    GridWidth  = 36
    GridHeight = 12
    GridUnit   = 13
    FontSize   = 14
    FontName   = "MS UI Gothic"

    def init_catalog (program_directory)
      locale_name  = get_locale_name
      if locale_name
        filename = File.join(program_directory,
                             sprintf("catalog.%s.txt", locale_name))
        @catalog = load_catalog(filename) if File.readable_file?(filename)
      end
    end

    def get_into_tasktray
      @in_tasktray = true
      window_icon = LoadIcon.call(0, 32512)
      create_trayicon(window_icon, "pdumpfs", 0)
      self.show(0)
    end

    def get_out_from_tasktray
      @in_tasktray = false
      delete_trayicon(0)
    end

    def add_controls
      font = @screen.factory.newfont(FontName, FontSize)
      self.class::const_set("DEFAULT_FONT", font)
      setDimension(GridWidth, GridHeight)

      s = WStyle::WS_TABSTOP
      addControl(VRStatic,   "from_label",    _("From"), 1,  1,  7, 2)
      addControl(VRStatic,   "to_label",      _("To"),   1,  4,  7, 2)
      addControl(VREditCombobox, "from_combobox", "",    9,  1, 20, 10, s)
      addControl(VRButton,   "from_button", _("Choose..."),  30,  1,  5, 2, s)
      addControl(VREditCombobox, "to_combobox",   "",    9,  4, 20, 10, s)
      addControl(VRButton,   "to_button",    _("Choose..."), 30,  4,  5, 2, s)
      addControl(VRButton,   "backup_button", _("Backup"),   15,  7,  6, 2, s)
      addStatusbar("")
    end

    def add_menus
      setMenu(newMenu.set([ [_("&File"),
                              [ [_("Choose &From directory"), "from_menu"],
                                [_("Choose &To directory"), "to_menu"],
                                VRMenu::SEPARATOR,
                                [_("&View the log"), "view_log_menu"],
                                [_("Clear log"), "clear_log_menu"],
                                [_("Clear history"), "clear_history_menu"],
                                VRMenu::SEPARATOR,
                                [_("Add to task scheduler"), "add_to_task_scheduler_menu"],
                                [_("Open task scheduler"), "open_task_scheduler_menu"],
                                VRMenu::SEPARATOR,
                                [_("Get &into Tasktray"), "tasktray_menu"],
                                [_("E&xit"), "exit_menu"]
                              ]],
                            [_("&Help"), 
                              [ [_("Open pdumpfs's web site"), "web_menu"],
                                [_("&About pdumpfs..."), "about_menu"]]]
                          ]))

      @traymenu = newPopupMenu
      @traymenu.set([ [_("Open pdumpfs"), "restore_menu"], 
                      [_("E&xit"), "exit_tray_menu"]
                    ])
      @insensitive_menus = [
        @exit_menu, @tasktray_menu,
        @restore_menu, @exit_tray_menu
      ]
    end

    def open_task_scheduler_menu_clicked
      task_clsid =
        "::{20D04FE0-3AEA-1069-A2D8-08002B30309D}\\::{D6277990-4C6A-11CF-8D87-00AA0060F5BF}"
      ShellExecute.call(0, "open", "explorer.exe", task_clsid, 0, SW_SHOWNORMAL);
    end

    def add_to_task_scheduler_menu_clicked
      begin
        validate_all
        value = VRLocalScreen.modalform(self, nil, TaskSchedulerDialog)
        return unless value
        hour = value.first
        min  = value.last
        command_line = sprintf('"%s" -l "%s" "%s" "%s"', 
                               get_program_file_name,
                               @log_file,
                               @from_combobox.text,
                               @to_combobox.text)
        at_args = sprintf("%d:%d /every:m,t,w,th,f,s,su %s", 
                          hour, min, command_line)
        retval = ShellExecute.call(0, "open", "at", at_args, 0, SW_HIDE)
        if retval > 32
          update_statusbar(_("A new task is added to the task scheduler."))
        else
          show_error(_("Failed to add a new task."))
        end
      rescue PdumpfsFormError
      rescue Exception => e
        show_error(e.message)
      end
    end

    def show_error (message)
      messageBox(message, _("Error"), 0)
    end      

    def self_trayrbuttonup (iconid)
      showPopup(@traymenu)
    end
    alias :self_traylbuttonup :self_trayrbuttonup

    def restore_menu_clicked
      get_out_from_tasktray
      show
    end

    def construct
      program_directory = get_program_directory
      @in_tasktray = false
      @log_file = File.join(program_directory, "pdumpfs.log")
      @config_file = File.join(program_directory, "pdumpfs.txt")
      @last_path = ""

      init_catalog(program_directory)
      add_controls
      add_menus
      clear_history
      load_config
      update_menu

      self.caption = "pdumpfs for Windows"
      delta_x, delta_y = get_delta_xy
      self.move(100, 100, 
                GridWidth  * GridUnit + delta_x, 
                GridHeight * GridUnit + delta_y)

      @mutex = Mutex.new
      @critical_thread = nil
    end

    def open_file (filename)
      ShellExecute.call(0, "open", filename, 0, 0, SW_SHOWNORMAL)
    end

    def save_config
      File.open(@config_file, "w") {|f|
        @from_combobox.eachString {|x| f.printf("from:%s\n", x) unless x.empty?}
        @to_combobox.eachString {|x| f.printf("to:%s\n", x) unless x.empty? }
        f.printf("tasktray:true\n") if @in_tasktray
      }
    end

    def load_config
      return unless File.readable_file?(@config_file)
      File.open(@config_file, "r") {|f|
        f.readlines.reverse.each {|line|
          m = /^(.*?):(.*)$/.match(line)
          next if m.nil?
          key   = m[1]
          value = m[2]
          case key
          when "from"
            add_history(@from_combobox, value)
          when "to"
            add_history(@to_combobox, value)
          when "tasktray"
            @in_tasktray = true
          else
            raise "unknown config: #{line}"
          end
        }
      }
    end

    def start
      if @in_tasktray
        get_into_tasktray
      else
        show
      end
    end

    def quit_graceful
      save_config
      exit
    end

    def update_statusbar (message)
      @statusbar.setTextOf(0, message)
    end
      
    def self_close
      if @critical_thread and @critical_thread.alive?
        update_statusbar(_("Backup process is interrupted"))
        @critical_thread.kill
        raise "should not be reached here"
      else
        quit_graceful
      end
    end

    def tasktray_menu_clicked
      get_into_tasktray
    end

    def view_log_menu_clicked
      open_file(@log_file)
    end

    def clear_log_menu_clicked
      File.unlink(@log_file)
      update_menu
    end

    def update_menuitem (menuitem, status)
      if status then menuitem.enable else menuitem.disable end
    end

    def histories_not_empty?
      not (combobox_empty?(@to_combobox) and combobox_empty?(@from_combobox))
    end

    def log_file_exist?
      File.exist?(@log_file)
    end

    def update_menu
      update_menuitem(@clear_history_menu, histories_not_empty?)
      update_menuitem(@clear_log_menu,     log_file_exist?)
      update_menuitem(@view_log_menu,      log_file_exist?)
    end

    def clear_history
      [@to_combobox, @from_combobox].each {|combobox|
        combobox.setListStrings([""])
        combobox.select(0)
        combobox.refresh
      }
    end

    def exit_tray_menu_clicked
      delete_trayicon(0)
      quit_graceful
    end

    def exit_menu_clicked
      quit_graceful
    end

    def clear_history_menu_clicked
      clear_history
      update_menu
    end

    # We cannot use VRCombobox#findStrings because of its behaviour.
    def combobox_find (combobox, dirname)
      index = -1
      i = 0
      combobox.eachString {|s|
        index = i if dirname == s
        i += 1
      }
      return index
    end

    def combobox_empty? (combobox)
      combobox.countStrings == 1 and combobox.getTextOf(0) == ""
    end

    def add_history (combobox, dirname)
      combobox.clearStrings if combobox_empty?(combobox)
      
      index = combobox_find(combobox, dirname)
      if index != -1
        combobox.deleteString(index)
      end
      combobox.addString(0, dirname)
      combobox.select(0)
    end

    def select_directory (combobox, name)
      default_path = if not combobox.text.empty? then
                       combobox.text
                     else
                       @last_path
                     end
      message = sprintf(_("Please select %s directory"), name)
      dirname = SWin::CommonDialog::selectDirectory(self, message, default_path)
      unless dirname.nil?
        add_history(combobox, dirname)
        update_menu
        @last_path = dirname
      end
    end

    def web_menu_clicked
      open_file("http://namazu.org/~satoru/pdumpfs/")
    end

    def about_menu_clicked
      copyright_notice = "Copyright (C) 2001-2004 Satoru Takabayashi"
      messageBox(sprintf("pdumpfs %s\n\n%s", 
                         Pdumpfs::VERSION,
                         copyright_notice),
                 _("About pdumpfs"), 0)
    end

    def from_button_clicked
      select_directory(@from_combobox, _("From"))
    end

    def to_button_clicked
      select_directory(@to_combobox, _("To"))
    end

    alias :from_menu_clicked :from_button_clicked
    alias :to_menu_clicked   :to_button_clicked

    class PdumpfsFormError < Exception; end
    def validate_directory (dir, name)
      if dir.nil? or dir.empty?
        messageBox(sprintf(_("Please select %s directory"), name),
                   _("warning"), 0)
        raise PdumpfsFormError.new
      elsif !File.directory?(dir)
        messageBox(sprintf(_("%s directory does not exist"), name),
                   _("warning"), 0)
        raise PdumpfsFormError.new
      end
    end

    def validate_filesystem (dir)
      unless ntfs?(dir)
        messageBox(sprintf(_("%s is not an NTFS"), dir), _("warning"), 0)
        raise PdumpfsFormError.new
      end
    end

    def sensitive_menus
      instance_variables.map {|x| 
        eval(x) 
      }.find_all {|x|
        x.is_a?(VRMenuItem)
      }.find_all {|x|
        not @insensitive_menus.find {|y| x == y }
      }
    end

    def disable_controls
      sensitive_menus.each {|menu| menu.disable }
      @controls.each {|id, control| control.enabled = false }
    end

    def enable_controls
      sensitive_menus.each {|menu| menu.enable }
      @controls.each {|id, control| control.enabled = true }
    end

    def do_critical 
      @mutex.synchronize { 
        disable_controls
        @critical_thread = Thread.new { yield }
        @critical_thread.abort_on_exception
        @critical_thread.join
        enable_controls
      }
    end

    # We don't use Pdumpfs#validate_directories to display message
    # boxes for errors.
    def validate_all (src = @from_combobox.text, dest = @to_combobox.text)
      validate_directory(src,  _("From"))
      validate_directory(dest, _("To"))
      validate_filesystem(dest)
      return true
    end

    def do_backup (src = @from_combobox.text, dest = @to_combobox.text)
      do_critical {
        begin
          validate_all(src, dest) or return
          add_history(@from_combobox, src)
          add_history(@to_combobox, dest)

          # We explicitly call doevents manually instead of
          # entrusting threads for performance reason.
          interval_proc = lambda { application.doevents }
          reporter = lambda {|status| update_statusbar(status) }

          pdumpfs = Pdumpfs::Pdumpfs.new(:reporter => reporter,
                                         :log_file => @log_file,
                                         :interval_proc => interval_proc
                                         )
          pdumpfs.start(src, dest)
          update_menu
          update_statusbar(_("Backup is finished!"))
        rescue PdumpfsFormError
        rescue Exception => e
          show_error(e.message)
        end
      }
    end

    def backup_button_clicked
      do_backup
    end
  end

  def start_gui
    style =  WStyle::WS_MAXIMIZEBOX|WStyle::WS_OVERLAPPEDWINDOW
    form = VRLocalScreen.modelessform(nil, style, PdumpfsForm)
    form.start
    VRLocalScreen.messageloop(true)
  end
end

module Pdumpfs
  VERSION = 1.3

  class NullMatcher
    def initialize (options = {})
    end

    def exclude? (path)
      false
    end
  end

  class FileMatcher
    def initialize (options = {})
      @patterns = options[:patterns]
      @globs    = options[:globs]
      @size     = calc_size(options[:size])
    end

    def calc_size (size)
      table   = { "K" => 1, "M" => 2, "G" => 3, "T" => 4, "P" => 5 }
      pattern = table.keys.join('')
      case size
      when nil
        -1
      when /^(\d+)([#{pattern}]?)$/i
        num  = Regexp.last_match[1].to_i
        unit = Regexp.last_match[2]
        num * 1024 ** (table[unit] or 0)
      else
        raise "Invalid size: #{size}"
      end
    end

    def exclude? (path)
      stat = File.lstat(path)

      if @size >= 0 and stat.file? and stat.size >= @size
        return true
      elsif @patterns.find {|pattern| pattern.match(path) }
        return true
      elsif stat.file? and
          @globs.find {|glob| File.fnmatch(glob, File.basename(path)) }
        return true
      end
      return false
    end
  end

  class Pdumpfs
    def initialize (config = {})
      @matcher  = (config[:matcher]  or NullMatcher.new)
      @reporter = (config[:reporter] or lambda {|x| puts x })
      @log_file = (config[:log_file] or nil)
      @dry_run  = (config[:dry_run] or false)
      @interval_proc = (config[:interval_proc] or lambda {})
      @written_bytes = 0
    end

    def create_latest_symlink (dest, today)
      latest_day = File.dirname(make_relative_path(today, dest))
      latest_symlink = File.join(dest, "latest")
      File.force_symlink(latest_day, latest_symlink)
    end

    def same_directory? (src, dest)
      src  = File.expand_path(src)
      dest = File.expand_path(dest)
      return src == dest
    end

    def sub_directory? (src, dest)
      src  = File.expand_path(src)
      dest = File.expand_path(dest)
      src  += File::SEPARATOR unless /#{File::SEPARATOR}$/.match(src)
      return /^#{Regexp.quote(src)}/.match(dest)
    end

    def start (src, dest, base = nil)
      start_time = Time.now

      if windows?
        src  = expand_special_folders(src)
        dest = expand_special_folders(dest)
      end
      if same_directory?(src, dest) or sub_directory?(src, dest)
        raise "cannot copy a directory, `#{src}', into itself, `#{dest}'"
      end
      # strip the trailing / to avoid basename(src) == '' for Ruby 1.6.x.
      src  = src.sub(%r!/+$!, "") unless src == '/' #'
      base = File.basename(src) unless base

      latest = latest_snapshot(start_time, src, dest, base)
      today  = File.join(dest, datedir(start_time), base)

      File.umask(0077)
      FileUtils.mkpath(today) unless @dry_run
      if latest
        update_snapshot(src, latest, today)
      else
        recursive_copy(src, today)
      end
      return if @dry_run

      create_latest_symlink(dest, today)
      elapsed = Time.now - start_time
      add_log_entry(src, today, elapsed) 
    end

    def convert_bytes (bytes)
      if bytes < 1024
        sprintf("%dB", bytes)
      elsif bytes < 1024 * 1000 # 1000kb
        sprintf("%.1fKB", bytes.to_f / 1024)
      elsif bytes < 1024 * 1024 * 1000  # 1000mb
        sprintf("%.1fMB", bytes.to_f / 1024 / 1024)
      else
        sprintf("%.1fGB", bytes.to_f / 1024 / 1024 / 1024)
      end
    end

    def add_log_entry (src, today, elapsed)
      return unless @log_file
      File.open(@log_file, "a") {|f|
        time  = Time.now.strftime("%Y-%m-%dT%H:%M:%S")
        bytes = convert_bytes(@written_bytes)
        f.printf("%s: %s -> %s (in %.2f sec, %s written)\n", 
                 time, src, today, elapsed, bytes)
      }
    end

    def same_file? (f1, f2)
      File.real_file?(f1) and File.real_file?(f2) and
        File.size(f1) == File.size(f2) and File.mtime(f1) == File.mtime(f2)
    end

    def datedir (date)
      s = File::SEPARATOR
      sprintf "%d%s%02d%s%02d", date.year, s, date.month, s, date.day
    end

    def past_date? (year, month, day, t)
      ([year, month, day] <=> [t.year, t.month, t.day]) < 0
    end

    def latest_snapshot (start_time, src, dest, base)
      dd   = "[0-9][0-9]"
      dddd = dd + dd
      # FIXME: Y10K problem.
      glob_path = File.join(dest, dddd, dd, dd)
      Dir.glob(glob_path).sort {|a, b| b <=> a }.find {|dir|
        day, month, year = File.split_all(dir).reverse.map {|x| x.to_i }
        path = File.join(dir, base)
        if File.directory?(path) and Date.valid_date?(year, month, day) and
            past_date?(year, month, day, start_time)
          return path
        end
      }
      return nil
    end

    # We don't use File.copy for calling @interval_proc.
    def copy_file (src, dest)
      File.open(src, 'rb') {|r|
        File.open(dest, 'wb') {|w|
          block_size = (r.stat.blksize or 8192)
          begin
            i = 0
            while true
              block = r.sysread(block_size)
              w.syswrite(block)
              i += 1
              @written_bytes += block.size
              @interval_proc.call if i % 10 == 0
            end
          rescue EOFError
          end
        }
      }
    end

    # incomplete substitute for cp -p
    def copy (src, dest)
      stat = File.stat(src)
      copy_file(src, dest)
      File.chmod(0200, dest) if windows?
      File.utime(stat.atime, stat.mtime, dest)
      File.chmod(stat.mode, dest) # not necessary. just to make sure
    end

    def detect_type (src, latest = nil)
      type = "unsupported"
      if File.real_directory?(src)
        type = "directory"
      else
        if latest and File.real_file?(latest)
          case File.ftype(src)
          when "file"
            if same_file?(src, latest)
              type = "unchanged"
            else
              type = "updated"
            end
          when "link"
            # the latest backup file is a real file but the
            # current source file is changed to symlink.
            type = "symlink"
          end
        else
          case File.ftype(src)
          when "file"
            type = "new_file"
          when "link"
            type = "symlink"
          end
        end
      end
      return type
    end

    def chown_if_root (type, src, today)
      return unless Process.uid == 0 and type != "unsupported"
      if type == "symlink"
        if File.respond_to?(:lchown)
          stat = File.lstat(src)
          File.lchown(stat.uid, stat.gid, today)
        end
      else
        stat = File.stat(src)
        File.chown(stat.uid, stat.gid, today)
      end
    end

    def report (type, file_name)
      message = sprintf("%-12s %s\n", type, file_name)
      @reporter.call(message)
      @interval_proc.call
    end

    def update_file (src, latest, today)
      type = detect_type(src, latest)
      report(type, src)
      return if @dry_run

      case type
      when "directory"
        FileUtils.mkpath(today)
      when "unchanged"
        File.force_link(latest, today)
      when "updated"
        copy(src, today)
      when "new_file"
        copy(src, today)
      when "symlink"
        File.force_symlink(File.readlink(src), today)
      when "unsupported"
        # just ignore it
      else
        raise "#{type}: shouldn't be reached here"
      end
      chown_if_root(type, src, today)
    end

    def restore_dir_attributes (dirs)
      dirs.each {|dir, stat|
        File.utime(stat.atime, stat.mtime, dir)
        File.chmod(stat.mode, dir)
      }
    end

    def make_relative_path (path, base)
      pattern = sprintf("^%s%s?", Regexp.quote(base), File::SEPARATOR)
      path.sub(Regexp.new(pattern), "")
    end

    def update_snapshot (src, latest, today)
      dirs = {};

      Find.find(src) do |s|      # path of the source file
        if @matcher.exclude?(s)
          if File.lstat(s).directory? then Find.prune() else next end
        end
        r = make_relative_path(s, src)
        l = File.join(latest, r)  # path of the latest  snapshot
        t = File.join(today, r)   # path of the today's snapshot

        begin
          update_file(s, l, t)
          dirs[t] = File.stat(s) if File.ftype(s) == "directory"
        rescue Errno::ENOENT, Errno::EACCES => e
          wprintf("%s: %s", src, e.message)
          next
        end
      end

      return if @dry_run
      restore_dir_attributes(dirs)
    end

    # incomplete substitute for cp -rp
    def recursive_copy (src, dest)
      dirs = {};

      Find.find(src) do |s|
        if @matcher.exclude?(s)
          if File.lstat(s).directory? then Find.prune() else next end
        end
        r = make_relative_path(s, src)
        t = File.join(dest, r)

        begin
          type = detect_type(s)
          report(type, s)
          next if @dry_run

          case type
          when "directory"
            FileUtils.mkpath(t)
          when "new_file"
            copy(s, t)
          when "symlink"
            File.force_symlink(File.readlink(s), t)
          when "unsupported"
            # just ignore it
          else
            raise "#{type}: shouldn't be reached here"
          end
          chown_if_root(type, s, t)
          dirs[t] = File.stat(s) if File.ftype(s) == "directory"
        rescue Errno::ENOENT, Errno::EACCES => e
          wprintf("%s: %s", s, e.message)
          next
        end
      end

      return if @dry_run
      restore_dir_attributes(dirs)
    end

    def validate_directories (src, dest)
      raise "No such directory: #{src}"  unless File.directory?(src)
      raise "No such directory: #{dest}" unless File.directory?(dest)

      if windows?
        unless ntfs?(dest)
          fstype = get_filesystem_type(dest)
          raise sprintf("only NTFS is supported but %s is %s.", dest, fstype)
        end
      end
    end
  end
end

def usage
  puts "Usage: pdumpfs SRC DEST [BASE]"
  puts "  -e, --exclude=PATTERN          exclude files/directories matching PATTERN"
  puts "  -s, --exclude-by-size=SIZE     exclude files larger than SIZE"
  puts "  -w, --exclude-by-glob=GLOB     exclude files matching GLOB"
  puts "  -l, --log-file=FILE            write a log to FILE"
  puts "  -v, --version                  print version information and exit"
  puts "  -q, --quiet                    suppress all normal output"
  puts "  -n, --dry-run                  don't actually run any commands"
  puts "  -h, --help                     show this help message"
  exit 0
end

def version
  puts "pdumpfs #{Pdumpfs::VERSION}"
  exit 0
end

def be_quiet
  devnull = if windows? then "NUL" else "/dev/null" end
  STDOUT.reopen(devnull)
end

def parse_options
  config = Hash.new
  patterns = Array.new
  globs = Array.new
  size  = nil

  parser = GetoptLong.new
  parser.set_options(['--exclude',  '-e',  GetoptLong::REQUIRED_ARGUMENT],
                     ['--exclude-by-size', GetoptLong::REQUIRED_ARGUMENT],
                     ['--exclude-by-glob', GetoptLong::REQUIRED_ARGUMENT],
                     ['--log-file', '-l',  GetoptLong::REQUIRED_ARGUMENT],
                     ['--quiet', '-q',     GetoptLong::NO_ARGUMENT],
                     ['--dry-run', '-n',   GetoptLong::NO_ARGUMENT],
                     ['--help', '-h',      GetoptLong::NO_ARGUMENT],
                     ['--version', '-v',   GetoptLong::NO_ARGUMENT],
                     ['--backtrace',       GetoptLong::NO_ARGUMENT]
                     )
  parser.quiet = true
  parser.each_option do |name, arg|
    case name
    when '--exclude'
      patterns.push(Regexp.new(arg))
    when '--exclude-by-size'
      size = arg
    when '--exclude-by-glob'
      unless File.respond_to?(:fnmatch)
        raise sprintf("--exclude-by-glob is not supported on Ruby %s", VERSION)
      end
      globs.push(arg)
    when '--log-file'
      config[:log_file] = arg
    when '--help'
      usage
    when '--quiet'
      be_quiet
    when '--dry-run'
      config[:dry_run] = true
    when '--backtrace'
      config[:backtrace] = true
    when '--version'
      version
    end
  end

  config[:matcher] = unless size.nil? and globs.empty? and patterns.empty?
                       Pdumpfs::FileMatcher.new(:size     => size,
                                                :globs    => globs,
                                                :patterns => patterns)
                     end
  usage if ARGV.length < 2

  src  = ARGV[0]
  dest = ARGV[1]
  base = ARGV[2]
  return src, dest, base, config
end

def main
  if has_vruby? and ARGV.empty?
    start_gui
  else
    begin
      src, dest, base, config = parse_options
      pdumpfs = Pdumpfs::Pdumpfs.new(config)
      pdumpfs.validate_directories(src, dest)
      pdumpfs.start(src, dest, base)
    rescue => e
      wprintf("%s", e.message)
      wprintf("%s", e.backtrace.join("\n")) if config[:backtrace]
      exit(1)
    end
  end
end

main if __FILE__ == $0