AlkantarClanX12
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'use strict'
const assert = require('assert')
const Buffer = require('buffer').Buffer
const realZlib = require('zlib')
const constants = exports.constants = require('./constants.js')
const Minipass = require('minipass')
const OriginalBufferConcat = Buffer.concat
class ZlibError extends Error {
constructor (err) {
super('zlib: ' + err.message)
this.code = err.code
this.errno = err.errno
/* istanbul ignore if */
if (!this.code)
this.code = 'ZLIB_ERROR'
this.message = 'zlib: ' + err.message
Error.captureStackTrace(this, this.constructor)
}
get name () {
return 'ZlibError'
}
}
// the Zlib class they all inherit from
// This thing manages the queue of requests, and returns
// true or false if there is anything in the queue when
// you call the .write() method.
const _opts = Symbol('opts')
const _flushFlag = Symbol('flushFlag')
const _finishFlushFlag = Symbol('finishFlushFlag')
const _fullFlushFlag = Symbol('fullFlushFlag')
const _handle = Symbol('handle')
const _onError = Symbol('onError')
const _sawError = Symbol('sawError')
const _level = Symbol('level')
const _strategy = Symbol('strategy')
const _ended = Symbol('ended')
const _defaultFullFlush = Symbol('_defaultFullFlush')
class ZlibBase extends Minipass {
constructor (opts, mode) {
if (!opts || typeof opts !== 'object')
throw new TypeError('invalid options for ZlibBase constructor')
super(opts)
this[_ended] = false
this[_opts] = opts
this[_flushFlag] = opts.flush
this[_finishFlushFlag] = opts.finishFlush
// this will throw if any options are invalid for the class selected
try {
this[_handle] = new realZlib[mode](opts)
} catch (er) {
// make sure that all errors get decorated properly
throw new ZlibError(er)
}
this[_onError] = (err) => {
this[_sawError] = true
// there is no way to cleanly recover.
// continuing only obscures problems.
this.close()
this.emit('error', err)
}
this[_handle].on('error', er => this[_onError](new ZlibError(er)))
this.once('end', () => this.close)
}
close () {
if (this[_handle]) {
this[_handle].close()
this[_handle] = null
this.emit('close')
}
}
reset () {
if (!this[_sawError]) {
assert(this[_handle], 'zlib binding closed')
return this[_handle].reset()
}
}
flush (flushFlag) {
if (this.ended)
return
if (typeof flushFlag !== 'number')
flushFlag = this[_fullFlushFlag]
this.write(Object.assign(Buffer.alloc(0), { [_flushFlag]: flushFlag }))
}
end (chunk, encoding, cb) {
if (chunk)
this.write(chunk, encoding)
this.flush(this[_finishFlushFlag])
this[_ended] = true
return super.end(null, null, cb)
}
get ended () {
return this[_ended]
}
write (chunk, encoding, cb) {
// process the chunk using the sync process
// then super.write() all the outputted chunks
if (typeof encoding === 'function')
cb = encoding, encoding = 'utf8'
if (typeof chunk === 'string')
chunk = Buffer.from(chunk, encoding)
if (this[_sawError])
return
assert(this[_handle], 'zlib binding closed')
// _processChunk tries to .close() the native handle after it's done, so we
// intercept that by temporarily making it a no-op.
const nativeHandle = this[_handle]._handle
const originalNativeClose = nativeHandle.close
nativeHandle.close = () => {}
const originalClose = this[_handle].close
this[_handle].close = () => {}
// It also calls `Buffer.concat()` at the end, which may be convenient
// for some, but which we are not interested in as it slows us down.
Buffer.concat = (args) => args
let result
try {
const flushFlag = typeof chunk[_flushFlag] === 'number'
? chunk[_flushFlag] : this[_flushFlag]
result = this[_handle]._processChunk(chunk, flushFlag)
// if we don't throw, reset it back how it was
Buffer.concat = OriginalBufferConcat
} catch (err) {
// or if we do, put Buffer.concat() back before we emit error
// Error events call into user code, which may call Buffer.concat()
Buffer.concat = OriginalBufferConcat
this[_onError](new ZlibError(err))
} finally {
if (this[_handle]) {
// Core zlib resets `_handle` to null after attempting to close the
// native handle. Our no-op handler prevented actual closure, but we
// need to restore the `._handle` property.
this[_handle]._handle = nativeHandle
nativeHandle.close = originalNativeClose
this[_handle].close = originalClose
// `_processChunk()` adds an 'error' listener. If we don't remove it
// after each call, these handlers start piling up.
this[_handle].removeAllListeners('error')
}
}
let writeReturn
if (result) {
if (Array.isArray(result) && result.length > 0) {
// The first buffer is always `handle._outBuffer`, which would be
// re-used for later invocations; so, we always have to copy that one.
writeReturn = super.write(Buffer.from(result[0]))
for (let i = 1; i < result.length; i++) {
writeReturn = super.write(result[i])
}
} else {
writeReturn = super.write(Buffer.from(result))
}
}
if (cb)
cb()
return writeReturn
}
}
class Zlib extends ZlibBase {
constructor (opts, mode) {
opts = opts || {}
opts.flush = opts.flush || constants.Z_NO_FLUSH
opts.finishFlush = opts.finishFlush || constants.Z_FINISH
super(opts, mode)
this[_fullFlushFlag] = constants.Z_FULL_FLUSH
this[_level] = opts.level
this[_strategy] = opts.strategy
}
params (level, strategy) {
if (this[_sawError])
return
if (!this[_handle])
throw new Error('cannot switch params when binding is closed')
// no way to test this without also not supporting params at all
/* istanbul ignore if */
if (!this[_handle].params)
throw new Error('not supported in this implementation')
if (this[_level] !== level || this[_strategy] !== strategy) {
this.flush(constants.Z_SYNC_FLUSH)
assert(this[_handle], 'zlib binding closed')
// .params() calls .flush(), but the latter is always async in the
// core zlib. We override .flush() temporarily to intercept that and
// flush synchronously.
const origFlush = this[_handle].flush
this[_handle].flush = (flushFlag, cb) => {
this.flush(flushFlag)
cb()
}
try {
this[_handle].params(level, strategy)
} finally {
this[_handle].flush = origFlush
}
/* istanbul ignore else */
if (this[_handle]) {
this[_level] = level
this[_strategy] = strategy
}
}
}
}
// minimal 2-byte header
class Deflate extends Zlib {
constructor (opts) {
super(opts, 'Deflate')
}
}
class Inflate extends Zlib {
constructor (opts) {
super(opts, 'Inflate')
}
}
// gzip - bigger header, same deflate compression
class Gzip extends Zlib {
constructor (opts) {
super(opts, 'Gzip')
}
}
class Gunzip extends Zlib {
constructor (opts) {
super(opts, 'Gunzip')
}
}
// raw - no header
class DeflateRaw extends Zlib {
constructor (opts) {
super(opts, 'DeflateRaw')
}
}
class InflateRaw extends Zlib {
constructor (opts) {
super(opts, 'InflateRaw')
}
}
// auto-detect header.
class Unzip extends Zlib {
constructor (opts) {
super(opts, 'Unzip')
}
}
class Brotli extends ZlibBase {
constructor (opts, mode) {
opts = opts || {}
opts.flush = opts.flush || constants.BROTLI_OPERATION_PROCESS
opts.finishFlush = opts.finishFlush || constants.BROTLI_OPERATION_FINISH
super(opts, mode)
this[_fullFlushFlag] = constants.BROTLI_OPERATION_FLUSH
}
}
class BrotliCompress extends Brotli {
constructor (opts) {
super(opts, 'BrotliCompress')
}
}
class BrotliDecompress extends Brotli {
constructor (opts) {
super(opts, 'BrotliDecompress')
}
}
exports.Deflate = Deflate
exports.Inflate = Inflate
exports.Gzip = Gzip
exports.Gunzip = Gunzip
exports.DeflateRaw = DeflateRaw
exports.InflateRaw = InflateRaw
exports.Unzip = Unzip
/* istanbul ignore else */
if (typeof realZlib.BrotliCompress === 'function') {
exports.BrotliCompress = BrotliCompress
exports.BrotliDecompress = BrotliDecompress
} else {
exports.BrotliCompress = exports.BrotliDecompress = class {
constructor () {
throw new Error('Brotli is not supported in this version of Node.js')
}
}
}