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Filename :
header.js
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'use strict' // parse a 512-byte header block to a data object, or vice-versa // encode returns `true` if a pax extended header is needed, because // the data could not be faithfully encoded in a simple header. // (Also, check header.needPax to see if it needs a pax header.) const Buffer = require('./buffer.js') const types = require('./types.js') const pathModule = require('path').posix const large = require('./large-numbers.js') const SLURP = Symbol('slurp') const TYPE = Symbol('type') class Header { constructor (data, off, ex, gex) { this.cksumValid = false this.needPax = false this.nullBlock = false this.block = null this.path = null this.mode = null this.uid = null this.gid = null this.size = null this.mtime = null this.cksum = null this[TYPE] = '0' this.linkpath = null this.uname = null this.gname = null this.devmaj = 0 this.devmin = 0 this.atime = null this.ctime = null if (Buffer.isBuffer(data)) this.decode(data, off || 0, ex, gex) else if (data) this.set(data) } decode (buf, off, ex, gex) { if (!off) off = 0 if (!buf || !(buf.length >= off + 512)) throw new Error('need 512 bytes for header') this.path = decString(buf, off, 100) this.mode = decNumber(buf, off + 100, 8) this.uid = decNumber(buf, off + 108, 8) this.gid = decNumber(buf, off + 116, 8) this.size = decNumber(buf, off + 124, 12) this.mtime = decDate(buf, off + 136, 12) this.cksum = decNumber(buf, off + 148, 12) // if we have extended or global extended headers, apply them now // See https://github.com/npm/node-tar/pull/187 this[SLURP](ex) this[SLURP](gex, true) // old tar versions marked dirs as a file with a trailing / this[TYPE] = decString(buf, off + 156, 1) if (this[TYPE] === '') this[TYPE] = '0' if (this[TYPE] === '0' && this.path.substr(-1) === '/') this[TYPE] = '5' // tar implementations sometimes incorrectly put the stat(dir).size // as the size in the tarball, even though Directory entries are // not able to have any body at all. In the very rare chance that // it actually DOES have a body, we weren't going to do anything with // it anyway, and it'll just be a warning about an invalid header. if (this[TYPE] === '5') this.size = 0 this.linkpath = decString(buf, off + 157, 100) if (buf.slice(off + 257, off + 265).toString() === 'ustar\u000000') { this.uname = decString(buf, off + 265, 32) this.gname = decString(buf, off + 297, 32) this.devmaj = decNumber(buf, off + 329, 8) this.devmin = decNumber(buf, off + 337, 8) if (buf[off + 475] !== 0) { // definitely a prefix, definitely >130 chars. const prefix = decString(buf, off + 345, 155) this.path = prefix + '/' + this.path } else { const prefix = decString(buf, off + 345, 130) if (prefix) this.path = prefix + '/' + this.path this.atime = decDate(buf, off + 476, 12) this.ctime = decDate(buf, off + 488, 12) } } let sum = 8 * 0x20 for (let i = off; i < off + 148; i++) { sum += buf[i] } for (let i = off + 156; i < off + 512; i++) { sum += buf[i] } this.cksumValid = sum === this.cksum if (this.cksum === null && sum === 8 * 0x20) this.nullBlock = true } [SLURP] (ex, global) { for (let k in ex) { // we slurp in everything except for the path attribute in // a global extended header, because that's weird. if (ex[k] !== null && ex[k] !== undefined && !(global && k === 'path')) this[k] = ex[k] } } encode (buf, off) { if (!buf) { buf = this.block = Buffer.alloc(512) off = 0 } if (!off) off = 0 if (!(buf.length >= off + 512)) throw new Error('need 512 bytes for header') const prefixSize = this.ctime || this.atime ? 130 : 155 const split = splitPrefix(this.path || '', prefixSize) const path = split[0] const prefix = split[1] this.needPax = split[2] this.needPax = encString(buf, off, 100, path) || this.needPax this.needPax = encNumber(buf, off + 100, 8, this.mode) || this.needPax this.needPax = encNumber(buf, off + 108, 8, this.uid) || this.needPax this.needPax = encNumber(buf, off + 116, 8, this.gid) || this.needPax this.needPax = encNumber(buf, off + 124, 12, this.size) || this.needPax this.needPax = encDate(buf, off + 136, 12, this.mtime) || this.needPax buf[off + 156] = this[TYPE].charCodeAt(0) this.needPax = encString(buf, off + 157, 100, this.linkpath) || this.needPax buf.write('ustar\u000000', off + 257, 8) this.needPax = encString(buf, off + 265, 32, this.uname) || this.needPax this.needPax = encString(buf, off + 297, 32, this.gname) || this.needPax this.needPax = encNumber(buf, off + 329, 8, this.devmaj) || this.needPax this.needPax = encNumber(buf, off + 337, 8, this.devmin) || this.needPax this.needPax = encString(buf, off + 345, prefixSize, prefix) || this.needPax if (buf[off + 475] !== 0) this.needPax = encString(buf, off + 345, 155, prefix) || this.needPax else { this.needPax = encString(buf, off + 345, 130, prefix) || this.needPax this.needPax = encDate(buf, off + 476, 12, this.atime) || this.needPax this.needPax = encDate(buf, off + 488, 12, this.ctime) || this.needPax } let sum = 8 * 0x20 for (let i = off; i < off + 148; i++) { sum += buf[i] } for (let i = off + 156; i < off + 512; i++) { sum += buf[i] } this.cksum = sum encNumber(buf, off + 148, 8, this.cksum) this.cksumValid = true return this.needPax } set (data) { for (let i in data) { if (data[i] !== null && data[i] !== undefined) this[i] = data[i] } } get type () { return types.name.get(this[TYPE]) || this[TYPE] } get typeKey () { return this[TYPE] } set type (type) { if (types.code.has(type)) this[TYPE] = types.code.get(type) else this[TYPE] = type } } const splitPrefix = (p, prefixSize) => { const pathSize = 100 let pp = p let prefix = '' let ret const root = pathModule.parse(p).root || '.' if (Buffer.byteLength(pp) < pathSize) ret = [pp, prefix, false] else { // first set prefix to the dir, and path to the base prefix = pathModule.dirname(pp) pp = pathModule.basename(pp) do { // both fit! if (Buffer.byteLength(pp) <= pathSize && Buffer.byteLength(prefix) <= prefixSize) ret = [pp, prefix, false] // prefix fits in prefix, but path doesn't fit in path else if (Buffer.byteLength(pp) > pathSize && Buffer.byteLength(prefix) <= prefixSize) ret = [pp.substr(0, pathSize - 1), prefix, true] else { // make path take a bit from prefix pp = pathModule.join(pathModule.basename(prefix), pp) prefix = pathModule.dirname(prefix) } } while (prefix !== root && !ret) // at this point, found no resolution, just truncate if (!ret) ret = [p.substr(0, pathSize - 1), '', true] } return ret } const decString = (buf, off, size) => buf.slice(off, off + size).toString('utf8').replace(/\0.*/, '') const decDate = (buf, off, size) => numToDate(decNumber(buf, off, size)) const numToDate = num => num === null ? null : new Date(num * 1000) const decNumber = (buf, off, size) => buf[off] & 0x80 ? large.parse(buf.slice(off, off + size)) : decSmallNumber(buf, off, size) const nanNull = value => isNaN(value) ? null : value const decSmallNumber = (buf, off, size) => nanNull(parseInt( buf.slice(off, off + size) .toString('utf8').replace(/\0.*$/, '').trim(), 8)) // the maximum encodable as a null-terminated octal, by field size const MAXNUM = { 12: 0o77777777777, 8 : 0o7777777 } const encNumber = (buf, off, size, number) => number === null ? false : number > MAXNUM[size] || number < 0 ? (large.encode(number, buf.slice(off, off + size)), true) : (encSmallNumber(buf, off, size, number), false) const encSmallNumber = (buf, off, size, number) => buf.write(octalString(number, size), off, size, 'ascii') const octalString = (number, size) => padOctal(Math.floor(number).toString(8), size) const padOctal = (string, size) => (string.length === size - 1 ? string : new Array(size - string.length - 1).join('0') + string + ' ') + '\0' const encDate = (buf, off, size, date) => date === null ? false : encNumber(buf, off, size, date.getTime() / 1000) // enough to fill the longest string we've got const NULLS = new Array(156).join('\0') // pad with nulls, return true if it's longer or non-ascii const encString = (buf, off, size, string) => string === null ? false : (buf.write(string + NULLS, off, size, 'utf8'), string.length !== Buffer.byteLength(string) || string.length > size) module.exports = Header