lib/zip/central_directory.rb
# frozen_string_literal: true
require 'forwardable'
require_relative 'dirtyable'
module Zip
class CentralDirectory # :nodoc:
extend Forwardable
include Dirtyable
END_OF_CD_SIG = 0x06054b50
ZIP64_END_OF_CD_SIG = 0x06064b50
ZIP64_EOCD_LOCATOR_SIG = 0x07064b50
STATIC_EOCD_SIZE = 22
ZIP64_STATIC_EOCD_SIZE = 56
ZIP64_EOCD_LOC_SIZE = 20
MAX_FILE_COMMENT_SIZE = (1 << 16) - 1
MAX_END_OF_CD_SIZE =
MAX_FILE_COMMENT_SIZE + STATIC_EOCD_SIZE + ZIP64_EOCD_LOC_SIZE
attr_accessor :comment
def_delegators :@entry_set,
:<<, :delete, :each, :entries, :find_entry, :glob,
:include?, :size
mark_dirty :<<, :comment=, :delete
def initialize(entries = EntrySet.new, comment = '') # :nodoc:
super(dirty_on_create: false)
@entry_set = entries.kind_of?(EntrySet) ? entries : EntrySet.new(entries)
@comment = comment
end
def read_from_stream(io)
read_eocds(io)
read_central_directory_entries(io)
end
def write_to_stream(io) # :nodoc:
cdir_offset = io.tell
@entry_set.each { |entry| entry.write_c_dir_entry(io) }
eocd_offset = io.tell
cdir_size = eocd_offset - cdir_offset
if Zip.write_zip64_support &&
(cdir_offset > 0xFFFFFFFF || cdir_size > 0xFFFFFFFF || @entry_set.size > 0xFFFF)
write_64_e_o_c_d(io, cdir_offset, cdir_size)
write_64_eocd_locator(io, eocd_offset)
end
write_e_o_c_d(io, cdir_offset, cdir_size)
end
# Reads the End of Central Directory Record (and the Zip64 equivalent if
# needs be) and returns the number of entries in the archive. This is a
# convenience method that avoids reading in all of the entry data to get a
# very quick entry count.
def count_entries(io)
read_eocds(io)
@size
end
def ==(other) # :nodoc:
return false unless other.kind_of?(CentralDirectory)
@entry_set.entries.sort == other.entries.sort && comment == other.comment
end
private
def write_e_o_c_d(io, offset, cdir_size) # :nodoc:
tmp = [
END_OF_CD_SIG,
0, # @numberOfThisDisk
0, # @numberOfDiskWithStartOfCDir
@entry_set ? [@entry_set.size, 0xFFFF].min : 0,
@entry_set ? [@entry_set.size, 0xFFFF].min : 0,
[cdir_size, 0xFFFFFFFF].min,
[offset, 0xFFFFFFFF].min,
@comment ? @comment.bytesize : 0
]
io << tmp.pack('VvvvvVVv')
io << @comment
end
def write_64_e_o_c_d(io, offset, cdir_size) # :nodoc:
tmp = [
ZIP64_END_OF_CD_SIG,
44, # size of zip64 end of central directory record (excludes signature and field itself)
VERSION_MADE_BY,
VERSION_NEEDED_TO_EXTRACT_ZIP64,
0, # @numberOfThisDisk
0, # @numberOfDiskWithStartOfCDir
@entry_set ? @entry_set.size : 0, # number of entries on this disk
@entry_set ? @entry_set.size : 0, # number of entries total
cdir_size, # size of central directory
offset # offset of start of central directory in its disk
]
io << tmp.pack('VQ<vvVVQ<Q<Q<Q<')
end
def write_64_eocd_locator(io, zip64_eocd_offset)
tmp = [
ZIP64_EOCD_LOCATOR_SIG,
0, # number of disk containing the start of zip64 eocd record
zip64_eocd_offset, # offset of the start of zip64 eocd record in its disk
1 # total number of disks
]
io << tmp.pack('VVQ<V')
end
def unpack_64_e_o_c_d(buffer) # :nodoc:
_, # ZIP64_END_OF_CD_SIG. We know we have this at this point.
@size_of_zip64_e_o_c_d,
@version_made_by,
@version_needed_for_extract,
@number_of_this_disk,
@number_of_disk_with_start_of_cdir,
@total_number_of_entries_in_cdir_on_this_disk,
@size,
@size_in_bytes,
@cdir_offset = buffer.unpack('VQ<vvVVQ<Q<Q<Q<')
zip64_extensible_data_size =
@size_of_zip64_e_o_c_d - ZIP64_STATIC_EOCD_SIZE + 12
@zip64_extensible_data = if zip64_extensible_data_size.zero?
''
else
buffer.slice(
ZIP64_STATIC_EOCD_SIZE,
zip64_extensible_data_size
)
end
end
def unpack_64_eocd_locator(buffer) # :nodoc:
_, # ZIP64_EOCD_LOCATOR_SIG. We know we have this at this point.
_, zip64_eocd_offset, = buffer.unpack('VVQ<V')
zip64_eocd_offset
end
def unpack_e_o_c_d(buffer) # :nodoc:
_, # END_OF_CD_SIG. We know we have this at this point.
num_disk,
num_disk_cdir,
num_cdir_disk,
num_entries,
size_in_bytes,
cdir_offset,
comment_length = buffer.unpack('VvvvvVVv')
@number_of_this_disk = num_disk unless num_disk == 0xFFFF
@number_of_disk_with_start_of_cdir = num_disk_cdir unless num_disk_cdir == 0xFFFF
@total_number_of_entries_in_cdir_on_this_disk = num_cdir_disk unless num_cdir_disk == 0xFFFF
@size = num_entries unless num_entries == 0xFFFF
@size_in_bytes = size_in_bytes unless size_in_bytes == 0xFFFFFFFF
@cdir_offset = cdir_offset unless cdir_offset == 0xFFFFFFFF
@comment = if comment_length.positive?
buffer.slice(STATIC_EOCD_SIZE, comment_length)
else
''
end
end
def read_central_directory_entries(io) # :nodoc:
# `StringIO` doesn't raise `EINVAL` if you seek beyond the current end,
# so we need to catch that *and* query `io#eof?` here.
eof = false
begin
io.seek(@cdir_offset, IO::SEEK_SET)
rescue Errno::EINVAL
eof = true
end
raise Error, 'Zip consistency problem while reading central directory entry' if eof || io.eof?
@entry_set = EntrySet.new
@size.times do
entry = Entry.read_c_dir_entry(io)
next unless entry
offset = if entry.zip64?
entry.extra['Zip64'].relative_header_offset
else
entry.local_header_offset
end
unless offset.nil?
io_save = io.tell
io.seek(offset, IO::SEEK_SET)
entry.read_extra_field(read_local_extra_field(io), local: true)
io.seek(io_save, IO::SEEK_SET)
end
@entry_set << entry
end
end
def read_local_extra_field(io)
buf = io.read(::Zip::LOCAL_ENTRY_STATIC_HEADER_LENGTH) || ''
return '' unless buf.bytesize == ::Zip::LOCAL_ENTRY_STATIC_HEADER_LENGTH
head, _, _, _, _, _, _, _, _, _, n_len, e_len = buf.unpack('VCCvvvvVVVvv')
return '' unless head == ::Zip::LOCAL_ENTRY_SIGNATURE
io.seek(n_len, IO::SEEK_CUR) # Skip over the entry name.
io.read(e_len)
end
def read_eocds(io) # :nodoc:
base_location, data = eocd_data(io)
eocd_location = data.rindex([END_OF_CD_SIG].pack('V'))
raise Error, 'Zip end of central directory signature not found' unless eocd_location
zip64_eocd_locator = data.rindex([ZIP64_EOCD_LOCATOR_SIG].pack('V'))
if zip64_eocd_locator
zip64_eocd_location = data.rindex([ZIP64_END_OF_CD_SIG].pack('V'))
zip64_eocd_data =
if zip64_eocd_location
data.slice(zip64_eocd_location..zip64_eocd_locator)
else
zip64_eocd_location = unpack_64_eocd_locator(
data.slice(zip64_eocd_locator..eocd_location)
)
unless zip64_eocd_location
raise Error, 'Zip64 end of central directory signature not found'
end
io.seek(zip64_eocd_location, IO::SEEK_SET)
io.read(base_location + zip64_eocd_locator - zip64_eocd_location)
end
unpack_64_e_o_c_d(zip64_eocd_data)
end
unpack_e_o_c_d(data.slice(eocd_location..-1))
end
def eocd_data(io)
begin
io.seek(-MAX_END_OF_CD_SIZE, IO::SEEK_END)
rescue Errno::EINVAL
io.seek(0, IO::SEEK_SET)
end
[io.tell, io.read]
end
end
end
# Copyright (C) 2002, 2003 Thomas Sondergaard
# rubyzip is free software; you can redistribute it and/or
# modify it under the terms of the ruby license.