Module: FileMode

Extended by:
ClassMethods
Defined in:
lib/file_mode.rb

Overview

Module for UNIX octal file modes. Classes that mixin this module must have a mode attribute that is the integer representation of the mode.

Defined Under Namespace

Modules: ClassMethods

Constant Summary collapse

OCTAL_DIGIT_TO_LISTING =

Mapping between a single octal digit and its permissions listing.

{
  0 => '---',
  1 => '--x',
  2 => '-w-',
  3 => '-wx',
  4 => 'r--',
  5 => 'r-x',
  6 => 'rw-',
  7 => 'rwx'
}

Class Method Summary collapse

Methods included from ClassMethods

group_executable?, group_readable?, group_writable?, other_executable?, other_readable?, other_writable?, setgid?, setuid?, sticky?, user_executable?, user_readable?, user_writable?

Class Method Details

.int_to_listing(int) ⇒ Object

Convert an integer into its permissions listing string. Listing strings may vary between operating systems (and even between applications on the same operating system). The listing output here matches the ouput from Linux/GNU coreutils ls(1).



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# File 'lib/file_mode.rb', line 120

def self.int_to_listing(int)
  perms = [ [6, 00700], [3, 00070], [0, 00007] ].map do |bitshift, mask|
    OCTAL_DIGIT_TO_LISTING[(int & mask) >> bitshift]
  end.join
  if 0 != int & 04000 # setuid
    perms[2] = perms[2] == 'x' ? 's' : 'S'
  end
  if 0 != int & 02000 # setgid
    perms[5] = perms[5] == 'x' ? 's' : 'S'
  end
  if 0 != int & 01000 # sticky
    perms[8] = perms[8] == 'x' ? 't' : 'T'
  end
  perms
end

.int_to_str(int) ⇒ Object

Convert an integer mode to a 4 digit octal string.



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# File 'lib/file_mode.rb', line 78

def self.int_to_str(int)
  int.to_s(8).rjust(4, '0')
end

.listing_to_int(listing) ⇒ Object

Convert a permissions listing string to its integer equivalent.



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# File 'lib/file_mode.rb', line 88

def self.listing_to_int(listing)
  int = listing.chars.map do |c|
    # l/L are for mandatory file locking on Solaris.
    %w{ - S T l L }.include?(c) ? 0 : 1
  end.join.to_i(2)
  int += 04000 if %w{ s S }.include?(listing[2]) # setuid
  int += 02000 if %w{ s S l L }.include?(listing[5]) # setgid
  int += 01000 if %w{ t T }.include?(listing[8]) # sticky
  int
end

.listing_to_str(listing) ⇒ Object

Convert permissions listing string to a string of its octal representation.



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# File 'lib/file_mode.rb', line 100

def self.listing_to_str(listing)
  int_to_str(listing_to_int(listing))
end

.str_to_int(str) ⇒ Object

Convert an octal string to an integer.



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# File 'lib/file_mode.rb', line 83

def self.str_to_int(str)
  str.to_i(8)
end

.str_to_listing(str) ⇒ Object

Convert an octal string into its permissions listing string.



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# File 'lib/file_mode.rb', line 137

def self.str_to_listing(str)
  int_to_listing(str.to_i(8))
end