lix-website/themes/lix/assets/bootstrap/node_modules/tar-stream/headers.js
2024-04-26 22:49:34 -06:00

284 lines
7.2 KiB
JavaScript

var toBuffer = require('to-buffer')
var alloc = require('buffer-alloc')
var ZEROS = '0000000000000000000'
var SEVENS = '7777777777777777777'
var ZERO_OFFSET = '0'.charCodeAt(0)
var USTAR = 'ustar\x0000'
var MASK = parseInt('7777', 8)
var clamp = function (index, len, defaultValue) {
if (typeof index !== 'number') return defaultValue
index = ~~index // Coerce to integer.
if (index >= len) return len
if (index >= 0) return index
index += len
if (index >= 0) return index
return 0
}
var toType = function (flag) {
switch (flag) {
case 0:
return 'file'
case 1:
return 'link'
case 2:
return 'symlink'
case 3:
return 'character-device'
case 4:
return 'block-device'
case 5:
return 'directory'
case 6:
return 'fifo'
case 7:
return 'contiguous-file'
case 72:
return 'pax-header'
case 55:
return 'pax-global-header'
case 27:
return 'gnu-long-link-path'
case 28:
case 30:
return 'gnu-long-path'
}
return null
}
var toTypeflag = function (flag) {
switch (flag) {
case 'file':
return 0
case 'link':
return 1
case 'symlink':
return 2
case 'character-device':
return 3
case 'block-device':
return 4
case 'directory':
return 5
case 'fifo':
return 6
case 'contiguous-file':
return 7
case 'pax-header':
return 72
}
return 0
}
var indexOf = function (block, num, offset, end) {
for (; offset < end; offset++) {
if (block[offset] === num) return offset
}
return end
}
var cksum = function (block) {
var sum = 8 * 32
for (var i = 0; i < 148; i++) sum += block[i]
for (var j = 156; j < 512; j++) sum += block[j]
return sum
}
var encodeOct = function (val, n) {
val = val.toString(8)
if (val.length > n) return SEVENS.slice(0, n) + ' '
else return ZEROS.slice(0, n - val.length) + val + ' '
}
/* Copied from the node-tar repo and modified to meet
* tar-stream coding standard.
*
* Source: https://github.com/npm/node-tar/blob/51b6627a1f357d2eb433e7378e5f05e83b7aa6cd/lib/header.js#L349
*/
function parse256 (buf) {
// first byte MUST be either 80 or FF
// 80 for positive, FF for 2's comp
var positive
if (buf[0] === 0x80) positive = true
else if (buf[0] === 0xFF) positive = false
else return null
// build up a base-256 tuple from the least sig to the highest
var zero = false
var tuple = []
for (var i = buf.length - 1; i > 0; i--) {
var byte = buf[i]
if (positive) tuple.push(byte)
else if (zero && byte === 0) tuple.push(0)
else if (zero) {
zero = false
tuple.push(0x100 - byte)
} else tuple.push(0xFF - byte)
}
var sum = 0
var l = tuple.length
for (i = 0; i < l; i++) {
sum += tuple[i] * Math.pow(256, i)
}
return positive ? sum : -1 * sum
}
var decodeOct = function (val, offset, length) {
val = val.slice(offset, offset + length)
offset = 0
// If prefixed with 0x80 then parse as a base-256 integer
if (val[offset] & 0x80) {
return parse256(val)
} else {
// Older versions of tar can prefix with spaces
while (offset < val.length && val[offset] === 32) offset++
var end = clamp(indexOf(val, 32, offset, val.length), val.length, val.length)
while (offset < end && val[offset] === 0) offset++
if (end === offset) return 0
return parseInt(val.slice(offset, end).toString(), 8)
}
}
var decodeStr = function (val, offset, length, encoding) {
return val.slice(offset, indexOf(val, 0, offset, offset + length)).toString(encoding)
}
var addLength = function (str) {
var len = Buffer.byteLength(str)
var digits = Math.floor(Math.log(len) / Math.log(10)) + 1
if (len + digits >= Math.pow(10, digits)) digits++
return (len + digits) + str
}
exports.decodeLongPath = function (buf, encoding) {
return decodeStr(buf, 0, buf.length, encoding)
}
exports.encodePax = function (opts) { // TODO: encode more stuff in pax
var result = ''
if (opts.name) result += addLength(' path=' + opts.name + '\n')
if (opts.linkname) result += addLength(' linkpath=' + opts.linkname + '\n')
var pax = opts.pax
if (pax) {
for (var key in pax) {
result += addLength(' ' + key + '=' + pax[key] + '\n')
}
}
return toBuffer(result)
}
exports.decodePax = function (buf) {
var result = {}
while (buf.length) {
var i = 0
while (i < buf.length && buf[i] !== 32) i++
var len = parseInt(buf.slice(0, i).toString(), 10)
if (!len) return result
var b = buf.slice(i + 1, len - 1).toString()
var keyIndex = b.indexOf('=')
if (keyIndex === -1) return result
result[b.slice(0, keyIndex)] = b.slice(keyIndex + 1)
buf = buf.slice(len)
}
return result
}
exports.encode = function (opts) {
var buf = alloc(512)
var name = opts.name
var prefix = ''
if (opts.typeflag === 5 && name[name.length - 1] !== '/') name += '/'
if (Buffer.byteLength(name) !== name.length) return null // utf-8
while (Buffer.byteLength(name) > 100) {
var i = name.indexOf('/')
if (i === -1) return null
prefix += prefix ? '/' + name.slice(0, i) : name.slice(0, i)
name = name.slice(i + 1)
}
if (Buffer.byteLength(name) > 100 || Buffer.byteLength(prefix) > 155) return null
if (opts.linkname && Buffer.byteLength(opts.linkname) > 100) return null
buf.write(name)
buf.write(encodeOct(opts.mode & MASK, 6), 100)
buf.write(encodeOct(opts.uid, 6), 108)
buf.write(encodeOct(opts.gid, 6), 116)
buf.write(encodeOct(opts.size, 11), 124)
buf.write(encodeOct((opts.mtime.getTime() / 1000) | 0, 11), 136)
buf[156] = ZERO_OFFSET + toTypeflag(opts.type)
if (opts.linkname) buf.write(opts.linkname, 157)
buf.write(USTAR, 257)
if (opts.uname) buf.write(opts.uname, 265)
if (opts.gname) buf.write(opts.gname, 297)
buf.write(encodeOct(opts.devmajor || 0, 6), 329)
buf.write(encodeOct(opts.devminor || 0, 6), 337)
if (prefix) buf.write(prefix, 345)
buf.write(encodeOct(cksum(buf), 6), 148)
return buf
}
exports.decode = function (buf, filenameEncoding) {
var typeflag = buf[156] === 0 ? 0 : buf[156] - ZERO_OFFSET
var name = decodeStr(buf, 0, 100, filenameEncoding)
var mode = decodeOct(buf, 100, 8)
var uid = decodeOct(buf, 108, 8)
var gid = decodeOct(buf, 116, 8)
var size = decodeOct(buf, 124, 12)
var mtime = decodeOct(buf, 136, 12)
var type = toType(typeflag)
var linkname = buf[157] === 0 ? null : decodeStr(buf, 157, 100, filenameEncoding)
var uname = decodeStr(buf, 265, 32)
var gname = decodeStr(buf, 297, 32)
var devmajor = decodeOct(buf, 329, 8)
var devminor = decodeOct(buf, 337, 8)
if (buf[345]) name = decodeStr(buf, 345, 155, filenameEncoding) + '/' + name
// to support old tar versions that use trailing / to indicate dirs
if (typeflag === 0 && name && name[name.length - 1] === '/') typeflag = 5
var c = cksum(buf)
// checksum is still initial value if header was null.
if (c === 8 * 32) return null
// valid checksum
if (c !== decodeOct(buf, 148, 8)) throw new Error('Invalid tar header. Maybe the tar is corrupted or it needs to be gunzipped?')
return {
name: name,
mode: mode,
uid: uid,
gid: gid,
size: size,
mtime: new Date(1000 * mtime),
type: type,
linkname: linkname,
uname: uname,
gname: gname,
devmajor: devmajor,
devminor: devminor
}
}