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