# Object-Oriented Pathname Class
#
# Author:: Tanaka Akira <akr@m17n.org>

# Pathname represents a pathname which locates a file in a filesystem.
#
# Pathname is immutable.  It has no method for destructive update.
#
class Pathname
  def initialize(path)
    @path = path.to_str.dup
    @path.freeze
  end

  def ==(other)
    return false unless Pathname === other
    other.to_s == @path
  end
  alias === ==
  alias eql? ==

  def <=>(other)
    return nil unless Pathname === other
    @path.tr('/', "\0") <=> other.to_s.tr('/', "\0")
  end

  def hash
    @path.hash
  end

  def to_s
    @path.dup
  end
  alias to_str to_s

  def inspect
    "#<#{self.class}:#{@path}>"
  end

  # cleanpath returns clean pathname of self which is without consecutive
  # slashes and useless dots.
  #
  # If true is given as the optional argument consider_symlink,
  # symbolic links are considered.  It makes more dots are retained.
  #
  # cleanpath doesn't access actual filesystem.
  def cleanpath(consider_symlink=false)
    if consider_symlink
      cleanpath_conservative
    else
      cleanpath_aggressive
    end
  end

  def cleanpath_aggressive # :nodoc:
    # cleanpath_aggressive assumes:
    # * no symlink
    # * all pathname prefix contained in the pathname is existing directory
    return Pathname.new('') if @path == ''
    absolute = absolute?
    names = []
    @path.scan(%r{[^/]+}) {|name|
      next if name == '.'
      if name == '..'
        if names.empty?
          next if absolute
        else
          if names.last != '..'
            names.pop
            next
          end
        end
      end
      names << name
    }
    return Pathname.new(absolute ? '/' : '.') if names.empty?
    path = absolute ? '/' : ''
    path << names.join('/')
    Pathname.new(path)
  end

  def cleanpath_conservative # :nodoc:
    return Pathname.new('') if @path == ''
    names = @path.scan(%r{[^/]+})
    last_dot = names.last == '.'
    names.delete('.')
    names.shift while names.first == '..' if absolute?
    return Pathname.new(absolute? ? '/' : '.') if names.empty?
    path = absolute? ? '/' : ''
    path << names.join('/')
    if names.last != '..'
      if last_dot
        path << '/.'
      elsif %r{/\z} =~ @path
        path << '/'
      end
    end
    Pathname.new(path)
  end

  # realpath returns real pathname of self in actual filesystem.
  #
  # If false is given for the optional argument force_absolute,
  # it may return relative pathname.
  # Otherwise it returns absolute pathname.
  def realpath(force_absolute=true)
    if relative? && force_absolute
      path = File.join Dir.pwd, @path
    else
      path = @path
    end
    stats = {}
    if %r{\A/} =~ path || realpath_root?('.', stats)
      resolved = '/'
    else
      resolved = '.'
    end
    resolved = realpath_rec(resolved, path, stats)
    Pathname.new(resolved)
  end

  def realpath_root?(path, stats) # :nodoc:
    path_stat = stats[path] ||= File.lstat(path)
    parent = path == '.' ? '..' : File.join(path, '..')
    parent_stat = stats[parent] ||= File.lstat(parent)
    path_stat.dev == parent_stat.dev && path_stat.ino == parent_stat.ino
  end

  def realpath_rec(resolved, unresolved, stats, rec={}) # :nodoc:
    unresolved.scan(%r{[^/]+}) {|f|
      next if f == '.'
      if f == '..'
        case resolved
        when '/'
          # Since the parent directory of '/' is '/', do nothing.
        when '.'
          resolved = '..'
          resolved = '/' if realpath_root?(resolved, stats)
        when %r{(\A|/)\.\.\z}
          resolved << '/..'
          resolved = '/' if realpath_root?(resolved, stats)
        when %r{/}
          resolved = File.dirname(resolved)
        else
          resolved = '.'
        end
      else
        path = resolved == '.' ? f : File.join(resolved, f)
        if File.lstat(path).symlink?
          raise Errno::ELOOP.new(path) if rec.include? path
          link = File.readlink path
          begin
            rec[path] = true
            resolved = realpath_rec(resolved, link, stats, rec)
          ensure
            rec.delete path
          end
        else
          resolved = path
        end
      end
    }
    resolved
  end

  # parent method returns parent directory, i.e. ".." is joined at last.
  def parent
    self.join('..')
  end

  # mountpoint? method returns true if self points a mountpoint.
  def mountpoint?
    begin
      stat1 = self.lstat
      stat2 = self.parent.lstat
      stat1.dev == stat2.dev && stat1.ino == stat2.ino ||
      stat1.dev != stat2.dev
    rescue Errno::ENOENT
      false
    end
  end

=begin
  def rootdir?
    stat1 = self.lstat
    stat2 = self.parent.lstat
    stat1.dev == stat2.dev && stat1.ino == stat2.ino
  end
=end

  # root? method is a predicate for root directory.
  # I.e. it returns true if the pathname consists of consecutive slashes.
  #
  # It doesn't access actual filesystem.
  # So it may return false for some pathnames
  # which points root such as "/usr/..".
  def root?
    %r{\A/+\z} =~ @path ? true : false
  end

=begin
  def working_directory?
    %r{\A\./*\z} =~ @path ? true : false
  end
=end

  # absolute? method is a predicate for absolute pathname.
  # It returns true if self is beginning with a slash.
  def absolute?
    %r{\A/} =~ @path ? true : false
  end

  # relative? method is a predicate for relative pathname.
  # It returns true unless self is beginning with a slash.
  def relative?
    !absolute?
  end

  # each_filename iterates over self for each filename components.
  def each_filename
    @path.scan(%r{[^/]+}) { yield $& }
  end

  # Pathname#+ return new pathname which is concatenated with self and
  # an argument.
  # If the argument is absolute pathname, it is just returned.
  def +(other)
    other = Pathname.new(other) unless Pathname === other
    if other.absolute?
      other
    elsif %r{/\z} =~ @path
      Pathname.new(@path + other.to_s)
    else
      Pathname.new(@path + '/' + other.to_s)
    end
  end

  # Pathname#children returns the children of the directory as an array of
  # pathnames.  I.e. it is similar to Pathname#entries except '.' and '..'
  # is not returned.
  def children
    Dir.entries(@path).map {|f|
      f == '.' || f == '..' ? nil : Pathname.new(f)
    }.compact
  end

end

# IO
class Pathname
  def foreachline(*args, &block) IO.foreach(@path, *args, &block) end
  alias each_line foreachline

  def read(*args) IO.read(@path, *args) end
  def readlines(*args) IO.readlines(@path, *args) end
  def sysopen(*args) IO.sysopen(@path, *args) end
end

# File
class Pathname
  def atime() File.atime(@path) end
  def ctime() File.ctime(@path) end
  def mtime() File.mtime(@path) end
  def chmod(mode) File.chmod(mode, @path) end
  def lchmod(mode) File.chmod(mode, @path) end
  def chown(owner, group) File.chown(owner, group, @path) end
  def lchown(owner, group) File.lchown(owner, group, @path) end
  def fnmatch(pattern, *args) File.fnmatch(pattern, @path, *args) end
  def fnmatch?(pattern, *args) File.fnmatch?(pattern, @path, *args) end
  def ftype() File.ftype(@path) end
  def link(old) File.link(old, @path) end
  def open(*args, &block) File.open(@path, *args, &block) end
  def readlink() Pathname.new(File.readlink(@path)) end
  def rename(to) File.rename(@path, to) end
  def stat() File.stat(@path) end
  def lstat() File.lstat(@path) end
  def symlink(old) File.symlink(old, @path) end
  def truncate(length) File.truncate(@path, length) end
  def utime(atime, mtime) File.utime(atime, mtime, @path) end
  def basename(*args) Pathname.new(File.basename(@path, *args)) end
  def dirname() Pathname.new(File.dirname(@path)) end
  def extname() File.extname(@path) end
  def expand_path(*args) Pathname.new(File.expand_path(@path, *args)) end
  def join(*args) Pathname.new(File.join(@path, *args)) end
  def split() File.split(@path).map {|f| Pathname.new(f) } end
end

# FileTest
class Pathname
  def blockdev?() FileTest.blockdev?(@path) end
  def chardev?() FileTest.chardev?(@path) end
  def executable?() FileTest.executable?(@path) end
  def executable_real?() FileTest.executable_real?(@path) end
  def exist?() FileTest.exist?(@path) end
  def grpowned?() FileTest.grpowned?(@path) end
  def directory?() FileTest.directory?(@path) end
  def file?() FileTest.file?(@path) end
  def pipe?() FileTest.pipe?(@path) end
  def socket?() FileTest.socket?(@path) end
  def owned?() FileTest.owned?(@path) end
  def readable?() FileTest.readable?(@path) end
  def readable_real?() FileTest.readable_real?(@path) end
  def setuid?() FileTest.setuid?(@path) end
  def setgid?() FileTest.setgid?(@path) end
  def size() FileTest.size(@path) end
  def size?() FileTest.size?(@path) end
  def sticky?() FileTest.sticky?(@path) end
  def symlink?() FileTest.symlink?(@path) end
  def writable?() FileTest.writable?(@path) end
  def writable_real?() FileTest.writable_real?(@path) end
  def zero?() FileTest.zero?(@path) end
end

# Dir
class Pathname
  def Pathname.glob(*args)
    if block_given?
      Dir.glob(*args) {|f| yield Pathname.new(f) }
    else
      Dir.glob(*args).map {|f| Pathname.new(f) }
    end
  end

  def Pathname.getwd() Pathname.new(Dir.getwd) end
  class << self; alias pwd getwd end

  def chdir(&block) Dir.chdir(@path, &block) end
  def chroot() Dir.chroot(@path) end
  def rmdir() Dir.rmdir(@path) end
  def entries() Dir.entries(@path).map {|f| Pathname.new(f) } end
  def dir_foreach(&block) Dir.foreach(@path) {|f| yield Pathname.new(f) } end
  def mkdir(*args) Dir.mkdir(@path, *args) end
  def opendir(&block) Dir.open(@path, &block) end
end

# Find
class Pathname
  def find(&block)
    require 'find'
    Find.find(@path) {|f| yield Pathname.new(f) }
  end
end

# FileUtils
class Pathname
  def mkpath
    require 'fileutils'
    FileUtils.mkpath(@path)
    nil
  end

  def rmtree
    # The name "rmtree" is borrowed from File::Path of Perl.
    # File::Path provides "mkpath" and "rmtree".
    require 'fileutils'
    FileUtils.rm_r(@path)
    nil
  end
end

# mixed
class Pathname
  def unlink()
    if FileTest.directory? @path
      Dir.unlink @path
    else
      File.unlink @path
    end
  end
  alias delete unlink

  def foreach(*args, &block)
    if FileTest.directory? @path
      # For polymorphism between Dir.foreach and IO.foreach,
      # Pathname#foreach doesn't yield Pathname object.
      Dir.foreach(@path, *args, &block)
    else
      IO.foreach(@path, *args, &block)
    end
  end
end

if $0 == __FILE__
  require 'test/unit'

  class PathnameTest < Test::Unit::TestCase # :nodoc:
    class AnotherStringLike # :nodoc:
      def initialize(s) @s = s end
      def to_str() @s end
      def ==(other) @s == other end
    end

    def test_equality
      obj = Pathname.new("a")
      str = "a"
      sym = :a
      ano = AnotherStringLike.new("a")
      assert_equal(false, obj == str)
      assert_equal(false, str == obj)
      assert_equal(false, obj == ano)
      assert_equal(false, ano == obj)
      assert_equal(false, obj == sym)
      assert_equal(false, sym == obj)

      obj2 = Pathname.new("a")
      assert_equal(true, obj == obj2)
      assert_equal(true, obj === obj2)
      assert_equal(true, obj.eql?(obj2))
    end

    def test_hashkey
      h = {}
      h[Pathname.new("a")] = 1
      h[Pathname.new("a")] = 2
      assert_equal(1, h.size)
    end

    def assert_pathname_cmp(e, s1, s2)
      p1 = Pathname.new(s1)
      p2 = Pathname.new(s2)
      r = p1 <=> p2
      assert(e == r,
        "#{p1.inspect} <=> #{p2.inspect}: <#{e}> expected but was <#{r}>")
    end
    def test_comparison
      assert_pathname_cmp( 0, "a", "a")
      assert_pathname_cmp( 1, "b", "a")
      assert_pathname_cmp(-1, "a", "b")
      ss = %w(
        a
        a/
        a/b
        a.
        a0
      )
      s1 = ss.shift
      ss.each {|s2|
        assert_pathname_cmp(-1, s1, s2)
        s1 = s2
      }
    end

    def test_comparison_string
      assert_equal(nil, Pathname.new("a") <=> "a")
      assert_equal(nil, "a" <=> Pathname.new("a"))
    end

    def test_syntactical
      assert_equal(true, Pathname.new("/").root?)
      assert_equal(true, Pathname.new("//").root?)
      assert_equal(true, Pathname.new("///").root?)
      assert_equal(false, Pathname.new("").root?)
      assert_equal(false, Pathname.new("a").root?)
      #assert_equal(true, Pathname.new(".").working_directory?)
      #assert_equal(true, Pathname.new("./").working_directory?)
      #assert_equal(true, Pathname.new(".//").working_directory?)
      #assert_equal(false, Pathname.new("").working_directory?)
      #assert_equal(false, Pathname.new("a").working_directory?)
    end

    def test_cleanpath
      assert_equal('/', Pathname.new('/').cleanpath(true).to_s)
      assert_equal('/', Pathname.new('//').cleanpath(true).to_s)
      assert_equal('', Pathname.new('').cleanpath(true).to_s)

      assert_equal('.', Pathname.new('.').cleanpath(true).to_s)
      assert_equal('..', Pathname.new('..').cleanpath(true).to_s)
      assert_equal('a', Pathname.new('a').cleanpath(true).to_s)
      assert_equal('/', Pathname.new('/.').cleanpath(true).to_s)
      assert_equal('/', Pathname.new('/..').cleanpath(true).to_s)
      assert_equal('/a', Pathname.new('/a').cleanpath(true).to_s)
      assert_equal('.', Pathname.new('./').cleanpath(true).to_s)
      assert_equal('..', Pathname.new('../').cleanpath(true).to_s)
      assert_equal('a/', Pathname.new('a/').cleanpath(true).to_s)

      assert_equal('a/b', Pathname.new('a//b').cleanpath(true).to_s)
      assert_equal('a/.', Pathname.new('a/.').cleanpath(true).to_s)
      assert_equal('a/.', Pathname.new('a/./').cleanpath(true).to_s)
      assert_equal('a/..', Pathname.new('a/../').cleanpath(true).to_s)
      assert_equal('/a/.', Pathname.new('/a/.').cleanpath(true).to_s)
      assert_equal('..', Pathname.new('./..').cleanpath(true).to_s)
      assert_equal('..', Pathname.new('../.').cleanpath(true).to_s)
      assert_equal('..', Pathname.new('./../').cleanpath(true).to_s)
      assert_equal('..', Pathname.new('.././').cleanpath(true).to_s)
      assert_equal('/', Pathname.new('/./..').cleanpath(true).to_s)
      assert_equal('/', Pathname.new('/../.').cleanpath(true).to_s)
      assert_equal('/', Pathname.new('/./../').cleanpath(true).to_s)
      assert_equal('/', Pathname.new('/.././').cleanpath(true).to_s)

      assert_equal('a/b/c', Pathname.new('a/b/c').cleanpath(true).to_s)
      assert_equal('b/c', Pathname.new('./b/c').cleanpath(true).to_s)
      assert_equal('a/c', Pathname.new('a/./c').cleanpath(true).to_s)
      assert_equal('a/b/.', Pathname.new('a/b/.').cleanpath(true).to_s)
      assert_equal('a/..', Pathname.new('a/../.').cleanpath(true).to_s)

      assert_equal('/a', Pathname.new('/../.././../a').cleanpath(true).to_s)
      assert_equal('a/b/../../../../c/../d', Pathname.new('a/b/../../../../c/../d').cleanpath(true).to_s)
    end

    def test_cleanpath_no_symlink
      assert_equal('/', Pathname.new('/').cleanpath.to_s)
      assert_equal('/', Pathname.new('//').cleanpath.to_s)
      assert_equal('', Pathname.new('').cleanpath.to_s)

      assert_equal('.', Pathname.new('.').cleanpath.to_s)
      assert_equal('..', Pathname.new('..').cleanpath.to_s)
      assert_equal('a', Pathname.new('a').cleanpath.to_s)
      assert_equal('/', Pathname.new('/.').cleanpath.to_s)
      assert_equal('/', Pathname.new('/..').cleanpath.to_s)
      assert_equal('/a', Pathname.new('/a').cleanpath.to_s)
      assert_equal('.', Pathname.new('./').cleanpath.to_s)
      assert_equal('..', Pathname.new('../').cleanpath.to_s)
      assert_equal('a', Pathname.new('a/').cleanpath.to_s)

      assert_equal('a/b', Pathname.new('a//b').cleanpath.to_s)
      assert_equal('a', Pathname.new('a/.').cleanpath.to_s)
      assert_equal('a', Pathname.new('a/./').cleanpath.to_s)
      assert_equal('.', Pathname.new('a/../').cleanpath.to_s)
      assert_equal('/a', Pathname.new('/a/.').cleanpath.to_s)
      assert_equal('..', Pathname.new('./..').cleanpath.to_s)
      assert_equal('..', Pathname.new('../.').cleanpath.to_s)
      assert_equal('..', Pathname.new('./../').cleanpath.to_s)
      assert_equal('..', Pathname.new('.././').cleanpath.to_s)
      assert_equal('/', Pathname.new('/./..').cleanpath.to_s)
      assert_equal('/', Pathname.new('/../.').cleanpath.to_s)
      assert_equal('/', Pathname.new('/./../').cleanpath.to_s)
      assert_equal('/', Pathname.new('/.././').cleanpath.to_s)

      assert_equal('a/b/c', Pathname.new('a/b/c').cleanpath.to_s)
      assert_equal('b/c', Pathname.new('./b/c').cleanpath.to_s)
      assert_equal('a/c', Pathname.new('a/./c').cleanpath.to_s)
      assert_equal('a/b', Pathname.new('a/b/.').cleanpath.to_s)
      assert_equal('.', Pathname.new('a/../.').cleanpath.to_s)

      assert_equal('/a', Pathname.new('/../.././../a').cleanpath.to_s)
      assert_equal('../../d', Pathname.new('a/b/../../../../c/../d').cleanpath.to_s)
    end

    def test_destructive_update
      path = Pathname.new("a")
      path.to_s.replace "b"
      assert_equal(Pathname.new("a"), path)
    end

  end
end