method

relative_path_from

v1_9_1_378 - Show latest stable - 0 notes - Class: Pathname

relative_path_from(base_directory) public

#relative_path_from returns a relative path from the argument to the receiver. If self is absolute, the argument must be absolute too. If self is relative, the argument must be relative too.

#relative_path_from doesn’t access the filesystem. It assumes no symlinks.

ArgumentError is raised when it cannot find a relative path.

This method has existed since 1.8.1.

Show source

# File lib/pathname.rb, line 726
  def relative_path_from(base_directory)
    dest_directory = self.cleanpath.to_s
    base_directory = base_directory.cleanpath.to_s
    dest_prefix = dest_directory
    dest_names = []
    while r = chop_basename(dest_prefix)
      dest_prefix, basename = r
      dest_names.unshift basename if basename != '.'
    end
    base_prefix = base_directory
    base_names = []
    while r = chop_basename(base_prefix)
      base_prefix, basename = r
      base_names.unshift basename if basename != '.'
    end
    unless SAME_PATHS[dest_prefix, base_prefix]
      raise ArgumentError, "different prefix: #{dest_prefix.inspect} and #{base_directory.inspect}"
    end
    while !dest_names.empty? &&
          !base_names.empty? &&
          SAME_PATHS[dest_names.first, base_names.first]
      dest_names.shift
      base_names.shift
    end
    if base_names.include? '..'
      raise ArgumentError, "base_directory has ..: #{base_directory.inspect}"
    end
    base_names.fill('..')
    relpath_names = base_names + dest_names
    if relpath_names.empty?
      Pathname.new('.')
    else
      Pathname.new(File.join(*relpath_names))
    end
  end

relative_path_from

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