CasperSecurity
'use strict';
var Buffer = require('buffer').Buffer;
var Transform = require('stream').Transform;
var binding = require('./binding');
var util = require('util');
var assert = require('assert').ok;
var kMaxLength = require('buffer').kMaxLength;
var kRangeErrorMessage = 'Cannot create final Buffer. It would be larger ' + 'than 0x' + kMaxLength.toString(16) + ' bytes';
// zlib doesn't provide these, so kludge them in following the same
// const naming scheme zlib uses.
binding.Z_MIN_WINDOWBITS = 8;
binding.Z_MAX_WINDOWBITS = 15;
binding.Z_DEFAULT_WINDOWBITS = 15;
// fewer than 64 bytes per chunk is stupid.
// technically it could work with as few as 8, but even 64 bytes
// is absurdly low. Usually a MB or more is best.
binding.Z_MIN_CHUNK = 64;
binding.Z_MAX_CHUNK = Infinity;
binding.Z_DEFAULT_CHUNK = 16 * 1024;
binding.Z_MIN_MEMLEVEL = 1;
binding.Z_MAX_MEMLEVEL = 9;
binding.Z_DEFAULT_MEMLEVEL = 8;
binding.Z_MIN_LEVEL = -1;
binding.Z_MAX_LEVEL = 9;
binding.Z_DEFAULT_LEVEL = binding.Z_DEFAULT_COMPRESSION;
// expose all the zlib constants
var bkeys = Object.keys(binding);
for (var bk = 0; bk < bkeys.length; bk++) {
var bkey = bkeys[bk];
if (bkey.match(/^Z/)) {
Object.defineProperty(exports, bkey, {
enumerable: true, value: binding[bkey], writable: false
});
}
}
// translation table for return codes.
var codes = {
Z_OK: binding.Z_OK,
Z_STREAM_END: binding.Z_STREAM_END,
Z_NEED_DICT: binding.Z_NEED_DICT,
Z_ERRNO: binding.Z_ERRNO,
Z_STREAM_ERROR: binding.Z_STREAM_ERROR,
Z_DATA_ERROR: binding.Z_DATA_ERROR,
Z_MEM_ERROR: binding.Z_MEM_ERROR,
Z_BUF_ERROR: binding.Z_BUF_ERROR,
Z_VERSION_ERROR: binding.Z_VERSION_ERROR
};
var ckeys = Object.keys(codes);
for (var ck = 0; ck < ckeys.length; ck++) {
var ckey = ckeys[ck];
codes[codes[ckey]] = ckey;
}
Object.defineProperty(exports, 'codes', {
enumerable: true, value: Object.freeze(codes), writable: false
});
exports.Deflate = Deflate;
exports.Inflate = Inflate;
exports.Gzip = Gzip;
exports.Gunzip = Gunzip;
exports.DeflateRaw = DeflateRaw;
exports.InflateRaw = InflateRaw;
exports.Unzip = Unzip;
exports.createDeflate = function (o) {
return new Deflate(o);
};
exports.createInflate = function (o) {
return new Inflate(o);
};
exports.createDeflateRaw = function (o) {
return new DeflateRaw(o);
};
exports.createInflateRaw = function (o) {
return new InflateRaw(o);
};
exports.createGzip = function (o) {
return new Gzip(o);
};
exports.createGunzip = function (o) {
return new Gunzip(o);
};
exports.createUnzip = function (o) {
return new Unzip(o);
};
// Convenience methods.
// compress/decompress a string or buffer in one step.
exports.deflate = function (buffer, opts, callback) {
if (typeof opts === 'function') {
callback = opts;
opts = {};
}
return zlibBuffer(new Deflate(opts), buffer, callback);
};
exports.deflateSync = function (buffer, opts) {
return zlibBufferSync(new Deflate(opts), buffer);
};
exports.gzip = function (buffer, opts, callback) {
if (typeof opts === 'function') {
callback = opts;
opts = {};
}
return zlibBuffer(new Gzip(opts), buffer, callback);
};
exports.gzipSync = function (buffer, opts) {
return zlibBufferSync(new Gzip(opts), buffer);
};
exports.deflateRaw = function (buffer, opts, callback) {
if (typeof opts === 'function') {
callback = opts;
opts = {};
}
return zlibBuffer(new DeflateRaw(opts), buffer, callback);
};
exports.deflateRawSync = function (buffer, opts) {
return zlibBufferSync(new DeflateRaw(opts), buffer);
};
exports.unzip = function (buffer, opts, callback) {
if (typeof opts === 'function') {
callback = opts;
opts = {};
}
return zlibBuffer(new Unzip(opts), buffer, callback);
};
exports.unzipSync = function (buffer, opts) {
return zlibBufferSync(new Unzip(opts), buffer);
};
exports.inflate = function (buffer, opts, callback) {
if (typeof opts === 'function') {
callback = opts;
opts = {};
}
return zlibBuffer(new Inflate(opts), buffer, callback);
};
exports.inflateSync = function (buffer, opts) {
return zlibBufferSync(new Inflate(opts), buffer);
};
exports.gunzip = function (buffer, opts, callback) {
if (typeof opts === 'function') {
callback = opts;
opts = {};
}
return zlibBuffer(new Gunzip(opts), buffer, callback);
};
exports.gunzipSync = function (buffer, opts) {
return zlibBufferSync(new Gunzip(opts), buffer);
};
exports.inflateRaw = function (buffer, opts, callback) {
if (typeof opts === 'function') {
callback = opts;
opts = {};
}
return zlibBuffer(new InflateRaw(opts), buffer, callback);
};
exports.inflateRawSync = function (buffer, opts) {
return zlibBufferSync(new InflateRaw(opts), buffer);
};
function zlibBuffer(engine, buffer, callback) {
var buffers = [];
var nread = 0;
engine.on('error', onError);
engine.on('end', onEnd);
engine.end(buffer);
flow();
function flow() {
var chunk;
while (null !== (chunk = engine.read())) {
buffers.push(chunk);
nread += chunk.length;
}
engine.once('readable', flow);
}
function onError(err) {
engine.removeListener('end', onEnd);
engine.removeListener('readable', flow);
callback(err);
}
function onEnd() {
var buf;
var err = null;
if (nread >= kMaxLength) {
err = new RangeError(kRangeErrorMessage);
} else {
buf = Buffer.concat(buffers, nread);
}
buffers = [];
engine.close();
callback(err, buf);
}
}
function zlibBufferSync(engine, buffer) {
if (typeof buffer === 'string') buffer = Buffer.from(buffer);
if (!Buffer.isBuffer(buffer)) throw new TypeError('Not a string or buffer');
var flushFlag = engine._finishFlushFlag;
return engine._processChunk(buffer, flushFlag);
}
// generic zlib
// minimal 2-byte header
function Deflate(opts) {
if (!(this instanceof Deflate)) return new Deflate(opts);
Zlib.call(this, opts, binding.DEFLATE);
}
function Inflate(opts) {
if (!(this instanceof Inflate)) return new Inflate(opts);
Zlib.call(this, opts, binding.INFLATE);
}
// gzip - bigger header, same deflate compression
function Gzip(opts) {
if (!(this instanceof Gzip)) return new Gzip(opts);
Zlib.call(this, opts, binding.GZIP);
}
function Gunzip(opts) {
if (!(this instanceof Gunzip)) return new Gunzip(opts);
Zlib.call(this, opts, binding.GUNZIP);
}
// raw - no header
function DeflateRaw(opts) {
if (!(this instanceof DeflateRaw)) return new DeflateRaw(opts);
Zlib.call(this, opts, binding.DEFLATERAW);
}
function InflateRaw(opts) {
if (!(this instanceof InflateRaw)) return new InflateRaw(opts);
Zlib.call(this, opts, binding.INFLATERAW);
}
// auto-detect header.
function Unzip(opts) {
if (!(this instanceof Unzip)) return new Unzip(opts);
Zlib.call(this, opts, binding.UNZIP);
}
function isValidFlushFlag(flag) {
return flag === binding.Z_NO_FLUSH || flag === binding.Z_PARTIAL_FLUSH || flag === binding.Z_SYNC_FLUSH || flag === binding.Z_FULL_FLUSH || flag === binding.Z_FINISH || flag === binding.Z_BLOCK;
}
// 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.
function Zlib(opts, mode) {
var _this = this;
this._opts = opts = opts || {};
this._chunkSize = opts.chunkSize || exports.Z_DEFAULT_CHUNK;
Transform.call(this, opts);
if (opts.flush && !isValidFlushFlag(opts.flush)) {
throw new Error('Invalid flush flag: ' + opts.flush);
}
if (opts.finishFlush && !isValidFlushFlag(opts.finishFlush)) {
throw new Error('Invalid flush flag: ' + opts.finishFlush);
}
this._flushFlag = opts.flush || binding.Z_NO_FLUSH;
this._finishFlushFlag = typeof opts.finishFlush !== 'undefined' ? opts.finishFlush : binding.Z_FINISH;
if (opts.chunkSize) {
if (opts.chunkSize < exports.Z_MIN_CHUNK || opts.chunkSize > exports.Z_MAX_CHUNK) {
throw new Error('Invalid chunk size: ' + opts.chunkSize);
}
}
if (opts.windowBits) {
if (opts.windowBits < exports.Z_MIN_WINDOWBITS || opts.windowBits > exports.Z_MAX_WINDOWBITS) {
throw new Error('Invalid windowBits: ' + opts.windowBits);
}
}
if (opts.level) {
if (opts.level < exports.Z_MIN_LEVEL || opts.level > exports.Z_MAX_LEVEL) {
throw new Error('Invalid compression level: ' + opts.level);
}
}
if (opts.memLevel) {
if (opts.memLevel < exports.Z_MIN_MEMLEVEL || opts.memLevel > exports.Z_MAX_MEMLEVEL) {
throw new Error('Invalid memLevel: ' + opts.memLevel);
}
}
if (opts.strategy) {
if (opts.strategy != exports.Z_FILTERED && opts.strategy != exports.Z_HUFFMAN_ONLY && opts.strategy != exports.Z_RLE && opts.strategy != exports.Z_FIXED && opts.strategy != exports.Z_DEFAULT_STRATEGY) {
throw new Error('Invalid strategy: ' + opts.strategy);
}
}
if (opts.dictionary) {
if (!Buffer.isBuffer(opts.dictionary)) {
throw new Error('Invalid dictionary: it should be a Buffer instance');
}
}
this._handle = new binding.Zlib(mode);
var self = this;
this._hadError = false;
this._handle.onerror = function (message, errno) {
// there is no way to cleanly recover.
// continuing only obscures problems.
_close(self);
self._hadError = true;
var error = new Error(message);
error.errno = errno;
error.code = exports.codes[errno];
self.emit('error', error);
};
var level = exports.Z_DEFAULT_COMPRESSION;
if (typeof opts.level === 'number') level = opts.level;
var strategy = exports.Z_DEFAULT_STRATEGY;
if (typeof opts.strategy === 'number') strategy = opts.strategy;
this._handle.init(opts.windowBits || exports.Z_DEFAULT_WINDOWBITS, level, opts.memLevel || exports.Z_DEFAULT_MEMLEVEL, strategy, opts.dictionary);
this._buffer = Buffer.allocUnsafe(this._chunkSize);
this._offset = 0;
this._level = level;
this._strategy = strategy;
this.once('end', this.close);
Object.defineProperty(this, '_closed', {
get: function () {
return !_this._handle;
},
configurable: true,
enumerable: true
});
}
util.inherits(Zlib, Transform);
Zlib.prototype.params = function (level, strategy, callback) {
if (level < exports.Z_MIN_LEVEL || level > exports.Z_MAX_LEVEL) {
throw new RangeError('Invalid compression level: ' + level);
}
if (strategy != exports.Z_FILTERED && strategy != exports.Z_HUFFMAN_ONLY && strategy != exports.Z_RLE && strategy != exports.Z_FIXED && strategy != exports.Z_DEFAULT_STRATEGY) {
throw new TypeError('Invalid strategy: ' + strategy);
}
if (this._level !== level || this._strategy !== strategy) {
var self = this;
this.flush(binding.Z_SYNC_FLUSH, function () {
assert(self._handle, 'zlib binding closed');
self._handle.params(level, strategy);
if (!self._hadError) {
self._level = level;
self._strategy = strategy;
if (callback) callback();
}
});
} else {
process.nextTick(callback);
}
};
Zlib.prototype.reset = function () {
assert(this._handle, 'zlib binding closed');
return this._handle.reset();
};
// This is the _flush function called by the transform class,
// internally, when the last chunk has been written.
Zlib.prototype._flush = function (callback) {
this._transform(Buffer.alloc(0), '', callback);
};
Zlib.prototype.flush = function (kind, callback) {
var _this2 = this;
var ws = this._writableState;
if (typeof kind === 'function' || kind === undefined && !callback) {
callback = kind;
kind = binding.Z_FULL_FLUSH;
}
if (ws.ended) {
if (callback) process.nextTick(callback);
} else if (ws.ending) {
if (callback) this.once('end', callback);
} else if (ws.needDrain) {
if (callback) {
this.once('drain', function () {
return _this2.flush(kind, callback);
});
}
} else {
this._flushFlag = kind;
this.write(Buffer.alloc(0), '', callback);
}
};
Zlib.prototype.close = function (callback) {
_close(this, callback);
process.nextTick(emitCloseNT, this);
};
function _close(engine, callback) {
if (callback) process.nextTick(callback);
// Caller may invoke .close after a zlib error (which will null _handle).
if (!engine._handle) return;
engine._handle.close();
engine._handle = null;
}
function emitCloseNT(self) {
self.emit('close');
}
Zlib.prototype._transform = function (chunk, encoding, cb) {
var flushFlag;
var ws = this._writableState;
var ending = ws.ending || ws.ended;
var last = ending && (!chunk || ws.length === chunk.length);
if (chunk !== null && !Buffer.isBuffer(chunk)) return cb(new Error('invalid input'));
if (!this._handle) return cb(new Error('zlib binding closed'));
// If it's the last chunk, or a final flush, we use the Z_FINISH flush flag
// (or whatever flag was provided using opts.finishFlush).
// If it's explicitly flushing at some other time, then we use
// Z_FULL_FLUSH. Otherwise, use Z_NO_FLUSH for maximum compression
// goodness.
if (last) flushFlag = this._finishFlushFlag;else {
flushFlag = this._flushFlag;
// once we've flushed the last of the queue, stop flushing and
// go back to the normal behavior.
if (chunk.length >= ws.length) {
this._flushFlag = this._opts.flush || binding.Z_NO_FLUSH;
}
}
this._processChunk(chunk, flushFlag, cb);
};
Zlib.prototype._processChunk = function (chunk, flushFlag, cb) {
var availInBefore = chunk && chunk.length;
var availOutBefore = this._chunkSize - this._offset;
var inOff = 0;
var self = this;
var async = typeof cb === 'function';
if (!async) {
var buffers = [];
var nread = 0;
var error;
this.on('error', function (er) {
error = er;
});
assert(this._handle, 'zlib binding closed');
do {
var res = this._handle.writeSync(flushFlag, chunk, // in
inOff, // in_off
availInBefore, // in_len
this._buffer, // out
this._offset, //out_off
availOutBefore); // out_len
} while (!this._hadError && callback(res[0], res[1]));
if (this._hadError) {
throw error;
}
if (nread >= kMaxLength) {
_close(this);
throw new RangeError(kRangeErrorMessage);
}
var buf = Buffer.concat(buffers, nread);
_close(this);
return buf;
}
assert(this._handle, 'zlib binding closed');
var req = this._handle.write(flushFlag, chunk, // in
inOff, // in_off
availInBefore, // in_len
this._buffer, // out
this._offset, //out_off
availOutBefore); // out_len
req.buffer = chunk;
req.callback = callback;
function callback(availInAfter, availOutAfter) {
// When the callback is used in an async write, the callback's
// context is the `req` object that was created. The req object
// is === this._handle, and that's why it's important to null
// out the values after they are done being used. `this._handle`
// can stay in memory longer than the callback and buffer are needed.
if (this) {
this.buffer = null;
this.callback = null;
}
if (self._hadError) return;
var have = availOutBefore - availOutAfter;
assert(have >= 0, 'have should not go down');
if (have > 0) {
var out = self._buffer.slice(self._offset, self._offset + have);
self._offset += have;
// serve some output to the consumer.
if (async) {
self.push(out);
} else {
buffers.push(out);
nread += out.length;
}
}
// exhausted the output buffer, or used all the input create a new one.
if (availOutAfter === 0 || self._offset >= self._chunkSize) {
availOutBefore = self._chunkSize;
self._offset = 0;
self._buffer = Buffer.allocUnsafe(self._chunkSize);
}
if (availOutAfter === 0) {
// Not actually done. Need to reprocess.
// Also, update the availInBefore to the availInAfter value,
// so that if we have to hit it a third (fourth, etc.) time,
// it'll have the correct byte counts.
inOff += availInBefore - availInAfter;
availInBefore = availInAfter;
if (!async) return true;
var newReq = self._handle.write(flushFlag, chunk, inOff, availInBefore, self._buffer, self._offset, self._chunkSize);
newReq.callback = callback; // this same function
newReq.buffer = chunk;
return;
}
if (!async) return false;
// finished with the chunk.
cb();
}
};
util.inherits(Deflate, Zlib);
util.inherits(Inflate, Zlib);
util.inherits(Gzip, Zlib);
util.inherits(Gunzip, Zlib);
util.inherits(DeflateRaw, Zlib);
util.inherits(InflateRaw, Zlib);
util.inherits(Unzip, Zlib);