vaguerent/lib/vagrant/util/file_checksum.rb

78 lines
1.8 KiB
Ruby

# Copyright (c) HashiCorp, Inc.
# SPDX-License-Identifier: BUSL-1.1
# This is an "interface" that should be implemented by any digest class
# passed into FileChecksum. Note that this isn't strictly enforced at
# the moment, and this class isn't directly used. It is merely here for
# documentation of structure of the class.
require "vagrant/errors"
class DigestClass
def update(string); end
def hexdigest; end
end
class FileChecksum
BUFFER_SIZE = 1024 * 8
# Supported file checksum
CHECKSUM_MAP = {
:md5 => Digest::MD5,
:sha1 => Digest::SHA1,
:sha256 => Digest::SHA256,
:sha384 => Digest::SHA384,
:sha512 => Digest::SHA512
}.freeze
# Initializes an object to calculate the checksum of a file. The given
# ``digest_klass`` should implement the ``DigestClass`` interface. Note
# that the built-in Ruby digest classes duck type this properly:
# Digest::MD5, Digest::SHA1, etc.
def initialize(path, digest_klass)
if digest_klass.is_a?(Class)
@digest_klass = digest_klass
else
@digest_klass = load_digest(digest_klass)
end
@path = path
end
# This calculates the checksum of the file and returns it as a
# string.
#
# @return [String]
def checksum
digest = @digest_klass.new
buf = ''
File.open(@path, "rb") do |f|
while !f.eof
begin
f.readpartial(BUFFER_SIZE, buf)
digest.update(buf)
rescue EOFError
# Although we check for EOF earlier, this seems to happen
# sometimes anyways [GH-2716].
break
end
end
end
digest.hexdigest
end
private
def load_digest(type)
digest = CHECKSUM_MAP[type.to_s.to_sym]
if digest.nil?
raise Vagrant::Errors::BoxChecksumInvalidType,
type: type.to_s,
types: CHECKSUM_MAP.keys.join(', ')
end
digest
end
end