gitlab-org--gitlab-foss/lib/gitlab/encoding_helper.rb
Bob Van Landuyt 8c5b3d0302 Allow streaming io objects into Gitaly
This allows us to set the encoding of an IO passed without reading it
into memory.

This is useful if we want to stream files into Gitaly. Like we do when
uploading a new file to the repository.
2019-04-01 20:17:40 +02:00

103 lines
3.5 KiB
Ruby

# frozen_string_literal: true
module Gitlab
module EncodingHelper
extend self
# This threshold is carefully tweaked to prevent usage of encodings detected
# by CharlockHolmes with low confidence. If CharlockHolmes confidence is low,
# we're better off sticking with utf8 encoding.
# Reason: git diff can return strings with invalid utf8 byte sequences if it
# truncates a diff in the middle of a multibyte character. In this case
# CharlockHolmes will try to guess the encoding and will likely suggest an
# obscure encoding with low confidence.
# There is a lot more info with this merge request:
# https://gitlab.com/gitlab-org/gitlab_git/merge_requests/77#note_4754193
ENCODING_CONFIDENCE_THRESHOLD = 50
def encode!(message)
message = force_encode_utf8(message)
return message if message.valid_encoding?
# return message if message type is binary
detect = CharlockHolmes::EncodingDetector.detect(message)
return message.force_encoding("BINARY") if detect_binary?(message, detect)
if detect && detect[:encoding] && detect[:confidence] > ENCODING_CONFIDENCE_THRESHOLD
# force detected encoding if we have sufficient confidence.
message.force_encoding(detect[:encoding])
end
# encode and clean the bad chars
message.replace clean(message)
rescue ArgumentError => e
return unless e.message.include?('unknown encoding name')
encoding = detect ? detect[:encoding] : "unknown"
"--broken encoding: #{encoding}"
end
def detect_binary?(data, detect = nil)
detect ||= CharlockHolmes::EncodingDetector.detect(data)
detect && detect[:type] == :binary && detect[:confidence] == 100
end
def detect_libgit2_binary?(data)
# EncodingDetector checks the first 1024 * 1024 bytes for NUL byte, libgit2 checks
# only the first 8000 (https://github.com/libgit2/libgit2/blob/2ed855a9e8f9af211e7274021c2264e600c0f86b/src/filter.h#L15),
# which is what we use below to keep a consistent behavior.
detect = CharlockHolmes::EncodingDetector.new(8000).detect(data)
detect && detect[:type] == :binary
end
def encode_utf8(message)
message = force_encode_utf8(message)
return message if message.valid_encoding?
detect = CharlockHolmes::EncodingDetector.detect(message)
if detect && detect[:encoding]
begin
CharlockHolmes::Converter.convert(message, detect[:encoding], 'UTF-8')
rescue ArgumentError => e
Rails.logger.warn("Ignoring error converting #{detect[:encoding]} into UTF8: #{e.message}")
''
end
else
clean(message)
end
rescue ArgumentError
nil
end
def encode_binary(str)
return "" if str.nil?
str.dup.force_encoding(Encoding::ASCII_8BIT)
end
def binary_io(str_or_io)
io = str_or_io.to_io.dup if str_or_io.respond_to?(:to_io)
io ||= StringIO.new(str_or_io.to_s.freeze)
io.tap { |io| io.set_encoding(Encoding::ASCII_8BIT) }
end
private
def force_encode_utf8(message)
raise ArgumentError unless message.respond_to?(:force_encoding)
return message if message.encoding == Encoding::UTF_8 && message.valid_encoding?
message = message.dup if message.respond_to?(:frozen?) && message.frozen?
message.force_encoding("UTF-8")
end
def clean(message)
message.encode("UTF-16BE", undef: :replace, invalid: :replace, replace: "".encode("UTF-16BE"))
.encode("UTF-8")
.gsub("\0".encode("UTF-8"), "")
end
end
end