Method: FakeFS::Pathname#relative_path_from

Defined in:
lib/fakefs/pathname.rb

#relative_path_from(base_directory) ⇒ Object

#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.



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# File 'lib/fakefs/pathname.rb', line 585

def relative_path_from(base_directory)
  dest_directory = 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]
    fail 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? '..'
    fail 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