##
# IO wrapper that creates digests of contents written to the IO it wraps.
class Gem::Package::DigestIO
##
# Collected digests for wrapped writes.
#
# {
# 'SHA1' => #<OpenSSL::Digest: [...]>,
# 'SHA512' => #<OpenSSL::Digest: [...]>,
# }
attr_reader :digests
##
# Wraps +io+ and updates digest for each of the digest algorithms in
# the +digests+ Hash. Returns the digests hash. Example:
#
# io = StringIO.new
# digests = {
# 'SHA1' => OpenSSL::Digest.new('SHA1'),
# 'SHA512' => OpenSSL::Digest.new('SHA512'),
# }
#
# Gem::Package::DigestIO.wrap io, digests do |digest_io|
# digest_io.write "hello"
# end
#
# digests['SHA1'].hexdigest #=> "aaf4c61d[...]"
# digests['SHA512'].hexdigest #=> "9b71d224[...]"
def self.wrap io, digests
digest_io = new io, digests
yield digest_io
return digests
end
##
# Creates a new DigestIO instance. Using ::wrap is recommended, see the
# ::wrap documentation for documentation of +io+ and +digests+.
def initialize io, digests
@io = io
@digests = digests
end
##
# Writes +data+ to the underlying IO and updates the digests
def write data
result = @io.write data
@digests.each do |_, digest|
digest << data
end
result
end
end
