class Mail::Encodings::TransferEncoding

Constants

NAME
PRIORITY

Public Class Methods

can_encode?(enc) click to toggle source

Override in subclasses to indicate that they can encode text that couldn’t be directly transported, e.g. Base64 has 7bit output, but it can encode binary.

# File lib/mail/encodings/transfer_encoding.rb, line 19
def self.can_encode?(enc)
  can_transport? enc
end
can_transport?(enc) click to toggle source

And encoding’s superclass can always transport it since the class hierarchy is arranged e.g. Base64 < 7bit < 8bit < Binary.

# File lib/mail/encodings/transfer_encoding.rb, line 12
def self.can_transport?(enc)
  enc && enc <= self
end
compatible_input?(str) click to toggle source
# File lib/mail/encodings/transfer_encoding.rb, line 27
def self.compatible_input?(str)
  true
end
cost(str) click to toggle source
# File lib/mail/encodings/transfer_encoding.rb, line 23
def self.cost(str)
  raise "Unimplemented"
end
lowest_cost(str, encodings) click to toggle source
# File lib/mail/encodings/transfer_encoding.rb, line 56
def self.lowest_cost(str, encodings)
  best = nil
  best_cost = nil

  encodings.each do |enc|
    # If the current choice cannot be transported safely, give priority
    # to other choices but allow it to be used as a fallback.
    this_cost = enc.cost(str) if enc.compatible_input?(str)

    if !best_cost || (this_cost && this_cost < best_cost)
      best_cost = this_cost
      best = enc
    elsif this_cost == best_cost
      best = enc if enc::PRIORITY < best::PRIORITY
    end
  end

  best
end
negotiate(message_encoding, source_encoding, str, allowed_encodings = nil) click to toggle source
# File lib/mail/encodings/transfer_encoding.rb, line 35
def self.negotiate(message_encoding, source_encoding, str, allowed_encodings = nil)
  message_encoding = Encodings.get_encoding(message_encoding) || Encodings.get_encoding('8bit')
  source_encoding  = Encodings.get_encoding(source_encoding)

  if message_encoding && source_encoding && message_encoding.can_transport?(source_encoding) && source_encoding.compatible_input?(str)
    source_encoding
  else
    renegotiate(message_encoding, source_encoding, str, allowed_encodings)
  end
end
renegotiate(message_encoding, source_encoding, str, allowed_encodings = nil) click to toggle source
# File lib/mail/encodings/transfer_encoding.rb, line 46
def self.renegotiate(message_encoding, source_encoding, str, allowed_encodings = nil)
  encodings = Encodings.get_all.select do |enc|
    (allowed_encodings.nil? || allowed_encodings.include?(enc)) &&
      message_encoding.can_transport?(enc) &&
      enc.can_encode?(source_encoding)
  end

  lowest_cost(str, encodings)
end
to_s() click to toggle source
# File lib/mail/encodings/transfer_encoding.rb, line 31
def self.to_s
  self::NAME
end