1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
|
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.
'use strict';
const Buffer = require('buffer').Buffer;
const Transform = require('_stream_transform');
const binding = process.binding('zlib');
const assert = require('assert').ok;
const kMaxLength = require('buffer').kMaxLength;
const kRangeErrorMessage = 'Cannot create final Buffer. It would be larger ' +
`than 0x${kMaxLength.toString(16)} bytes`;
const constants = process.binding('constants').zlib;
const { inherits } = require('util');
const { isArrayBufferView } = require('internal/util/types');
// translation table for return codes.
const codes = {
Z_OK: constants.Z_OK,
Z_STREAM_END: constants.Z_STREAM_END,
Z_NEED_DICT: constants.Z_NEED_DICT,
Z_ERRNO: constants.Z_ERRNO,
Z_STREAM_ERROR: constants.Z_STREAM_ERROR,
Z_DATA_ERROR: constants.Z_DATA_ERROR,
Z_MEM_ERROR: constants.Z_MEM_ERROR,
Z_BUF_ERROR: constants.Z_BUF_ERROR,
Z_VERSION_ERROR: constants.Z_VERSION_ERROR
};
const ckeys = Object.keys(codes);
for (var ck = 0; ck < ckeys.length; ck++) {
var ckey = ckeys[ck];
codes[codes[ckey]] = ckey;
}
function isInvalidFlushFlag(flag) {
return typeof flag !== 'number' ||
flag < constants.Z_NO_FLUSH ||
flag > constants.Z_BLOCK;
// Covers: constants.Z_NO_FLUSH (0),
// constants.Z_PARTIAL_FLUSH (1),
// constants.Z_SYNC_FLUSH (2),
// constants.Z_FULL_FLUSH (3),
// constants.Z_FINISH (4), and
// constants.Z_BLOCK (5)
}
function isInvalidStrategy(strategy) {
return typeof strategy !== 'number' ||
strategy < constants.Z_DEFAULT_STRATEGY ||
strategy > constants.Z_FIXED;
// Covers: constants.Z_FILTERED, (1)
// constants.Z_HUFFMAN_ONLY (2),
// constants.Z_RLE (3),
// constants.Z_FIXED (4), and
// constants.Z_DEFAULT_STRATEGY (0)
}
function responseData(engine, buffer) {
if (engine._opts.info) {
return { buffer, engine };
}
return buffer;
}
function zlibBuffer(engine, buffer, callback) {
// Streams do not support non-Buffer ArrayBufferViews yet. Convert it to a
// Buffer without copying.
if (isArrayBufferView(buffer) &&
Object.getPrototypeOf(buffer) !== Buffer.prototype) {
buffer = Buffer.from(buffer.buffer, buffer.byteOffset, buffer.byteLength);
}
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.byteLength;
}
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, responseData(engine, buf));
}
}
function zlibBufferSync(engine, buffer) {
if (typeof buffer === 'string')
buffer = Buffer.from(buffer);
else if (!isArrayBufferView(buffer))
throw new TypeError('"buffer" argument must be a string, Buffer, ' +
'TypedArray, or DataView');
var flushFlag = engine._finishFlushFlag;
return responseData(engine, engine._processChunk(buffer, flushFlag));
}
function zlibOnError(message, errno) {
// there is no way to cleanly recover.
// continuing only obscures problems.
_close(this);
this._hadError = true;
var error = new Error(message);
error.errno = errno;
error.code = codes[errno];
this.emit('error', error);
}
function flushCallback(level, strategy, callback) {
assert(this._handle, 'zlib binding closed');
this._handle.params(level, strategy);
if (!this._hadError) {
this._level = level;
this._strategy = strategy;
if (callback) callback();
}
}
// 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) {
opts = opts || {};
Transform.call(this, opts);
this.bytesRead = 0;
this._opts = opts;
this._chunkSize = opts.chunkSize || constants.Z_DEFAULT_CHUNK;
if (opts.flush && isInvalidFlushFlag(opts.flush)) {
throw new RangeError('Invalid flush flag: ' + opts.flush);
}
if (opts.finishFlush && isInvalidFlushFlag(opts.finishFlush)) {
throw new RangeError('Invalid flush flag: ' + opts.finishFlush);
}
this._flushFlag = opts.flush || constants.Z_NO_FLUSH;
this._finishFlushFlag = opts.finishFlush !== undefined ?
opts.finishFlush : constants.Z_FINISH;
this._scheduledFlushFlag = constants.Z_NO_FLUSH;
if (opts.chunkSize !== undefined) {
if (opts.chunkSize < constants.Z_MIN_CHUNK) {
throw new RangeError('Invalid chunk size: ' + opts.chunkSize);
}
}
if (opts.windowBits !== undefined) {
if (opts.windowBits < constants.Z_MIN_WINDOWBITS ||
opts.windowBits > constants.Z_MAX_WINDOWBITS) {
throw new RangeError('Invalid windowBits: ' + opts.windowBits);
}
}
if (opts.level !== undefined) {
if (opts.level < constants.Z_MIN_LEVEL ||
opts.level > constants.Z_MAX_LEVEL) {
throw new RangeError('Invalid compression level: ' + opts.level);
}
}
if (opts.memLevel !== undefined) {
if (opts.memLevel < constants.Z_MIN_MEMLEVEL ||
opts.memLevel > constants.Z_MAX_MEMLEVEL) {
throw new RangeError('Invalid memLevel: ' + opts.memLevel);
}
}
if (opts.strategy !== undefined && isInvalidStrategy(opts.strategy))
throw new TypeError('Invalid strategy: ' + opts.strategy);
if (opts.dictionary !== undefined) {
if (!isArrayBufferView(opts.dictionary)) {
throw new TypeError(
'Invalid dictionary: it should be a Buffer, TypedArray, or DataView');
}
}
this._handle = new binding.Zlib(mode);
this._handle.onerror = zlibOnError.bind(this);
this._hadError = false;
var level = constants.Z_DEFAULT_COMPRESSION;
if (Number.isFinite(opts.level)) {
level = opts.level;
}
var strategy = constants.Z_DEFAULT_STRATEGY;
if (Number.isFinite(opts.strategy)) {
strategy = opts.strategy;
}
var windowBits = constants.Z_DEFAULT_WINDOWBITS;
if (Number.isFinite(opts.windowBits)) {
windowBits = opts.windowBits;
}
var memLevel = constants.Z_DEFAULT_MEMLEVEL;
if (Number.isFinite(opts.memLevel)) {
memLevel = opts.memLevel;
}
this._handle.init(windowBits,
level,
memLevel,
strategy,
opts.dictionary);
this._buffer = Buffer.allocUnsafe(this._chunkSize);
this._offset = 0;
this._level = level;
this._strategy = strategy;
this.once('end', this.close);
}
inherits(Zlib, Transform);
Object.defineProperty(Zlib.prototype, '_closed', {
configurable: true,
enumerable: true,
get() {
return !this._handle;
}
});
Zlib.prototype.params = function params(level, strategy, callback) {
if (level < constants.Z_MIN_LEVEL ||
level > constants.Z_MAX_LEVEL) {
throw new RangeError('Invalid compression level: ' + level);
}
if (isInvalidStrategy(strategy))
throw new TypeError('Invalid strategy: ' + strategy);
if (this._level !== level || this._strategy !== strategy) {
this.flush(constants.Z_SYNC_FLUSH,
flushCallback.bind(this, level, strategy, callback));
} else {
process.nextTick(callback);
}
};
Zlib.prototype.reset = function reset() {
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 _flush(callback) {
this._transform(Buffer.alloc(0), '', callback);
};
// If a flush is scheduled while another flush is still pending, a way to figure
// out which one is the "stronger" flush is needed.
// Roughly, the following holds:
// Z_NO_FLUSH (< Z_TREES) < Z_BLOCK < Z_PARTIAL_FLUSH <
// Z_SYNC_FLUSH < Z_FULL_FLUSH < Z_FINISH
const flushiness = [];
let i = 0;
for (const flushFlag of [constants.Z_NO_FLUSH, constants.Z_BLOCK,
constants.Z_PARTIAL_FLUSH, constants.Z_SYNC_FLUSH,
constants.Z_FULL_FLUSH, constants.Z_FINISH]) {
flushiness[flushFlag] = i++;
}
function maxFlush(a, b) {
return flushiness[a] > flushiness[b] ? a : b;
}
Zlib.prototype.flush = function flush(kind, callback) {
var ws = this._writableState;
if (typeof kind === 'function' || (kind === undefined && !callback)) {
callback = kind;
kind = constants.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) {
const alreadyHadFlushScheduled =
this._scheduledFlushFlag !== constants.Z_NO_FLUSH;
this._scheduledFlushFlag = maxFlush(kind, this._scheduledFlushFlag);
// If a callback was passed, always register a new `drain` + flush handler,
// mostly because that’s simpler and flush callbacks piling up is a rare
// thing anyway.
if (!alreadyHadFlushScheduled || callback) {
const drainHandler = () => this.flush(this._scheduledFlushFlag, callback);
this.once('drain', drainHandler);
}
} else {
this._flushFlag = kind;
this.write(Buffer.alloc(0), '', callback);
this._scheduledFlushFlag = constants.Z_NO_FLUSH;
}
};
Zlib.prototype.close = function close(callback) {
_close(this, callback);
process.nextTick(emitCloseNT, this);
};
Zlib.prototype._transform = function _transform(chunk, encoding, cb) {
var flushFlag;
var ws = this._writableState;
var ending = ws.ending || ws.ended;
var last = ending && (!chunk || ws.length === chunk.byteLength);
if (chunk !== null && !isArrayBufferView(chunk))
return cb(new TypeError('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.byteLength >= ws.length) {
this._flushFlag = this._opts.flush || constants.Z_NO_FLUSH;
}
}
this._processChunk(chunk, flushFlag, cb);
};
Zlib.prototype._processChunk = function _processChunk(chunk, flushFlag, cb) {
var availInBefore = chunk && chunk.byteLength;
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;
if (self.destroyed)
return;
var have = availOutBefore - availOutAfter;
assert(have >= 0, 'have should not go down');
self.bytesRead += availInBefore - availInAfter;
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.byteLength;
}
}
// 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();
}
};
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');
}
// generic zlib
// minimal 2-byte header
function Deflate(opts) {
if (!(this instanceof Deflate))
return new Deflate(opts);
Zlib.call(this, opts, constants.DEFLATE);
}
inherits(Deflate, Zlib);
function Inflate(opts) {
if (!(this instanceof Inflate))
return new Inflate(opts);
Zlib.call(this, opts, constants.INFLATE);
}
inherits(Inflate, Zlib);
function Gzip(opts) {
if (!(this instanceof Gzip))
return new Gzip(opts);
Zlib.call(this, opts, constants.GZIP);
}
inherits(Gzip, Zlib);
function Gunzip(opts) {
if (!(this instanceof Gunzip))
return new Gunzip(opts);
Zlib.call(this, opts, constants.GUNZIP);
}
inherits(Gunzip, Zlib);
function DeflateRaw(opts) {
if (opts && opts.windowBits === 8) opts.windowBits = 9;
if (!(this instanceof DeflateRaw))
return new DeflateRaw(opts);
Zlib.call(this, opts, constants.DEFLATERAW);
}
inherits(DeflateRaw, Zlib);
function InflateRaw(opts) {
if (!(this instanceof InflateRaw))
return new InflateRaw(opts);
Zlib.call(this, opts, constants.INFLATERAW);
}
inherits(InflateRaw, Zlib);
function Unzip(opts) {
if (!(this instanceof Unzip))
return new Unzip(opts);
Zlib.call(this, opts, constants.UNZIP);
}
inherits(Unzip, Zlib);
function createConvenienceMethod(type, sync) {
if (sync) {
return function(buffer, opts) {
return zlibBufferSync(new type(opts), buffer);
};
} else {
return function(buffer, opts, callback) {
if (typeof opts === 'function') {
callback = opts;
opts = {};
}
return zlibBuffer(new type(opts), buffer, callback);
};
}
}
function createProperty(type) {
return {
configurable: true,
enumerable: true,
value: type
};
}
module.exports = {
Deflate,
Inflate,
Gzip,
Gunzip,
DeflateRaw,
InflateRaw,
Unzip,
// Convenience methods.
// compress/decompress a string or buffer in one step.
deflate: createConvenienceMethod(Deflate, false),
deflateSync: createConvenienceMethod(Deflate, true),
gzip: createConvenienceMethod(Gzip, false),
gzipSync: createConvenienceMethod(Gzip, true),
deflateRaw: createConvenienceMethod(DeflateRaw, false),
deflateRawSync: createConvenienceMethod(DeflateRaw, true),
unzip: createConvenienceMethod(Unzip, false),
unzipSync: createConvenienceMethod(Unzip, true),
inflate: createConvenienceMethod(Inflate, false),
inflateSync: createConvenienceMethod(Inflate, true),
gunzip: createConvenienceMethod(Gunzip, false),
gunzipSync: createConvenienceMethod(Gunzip, true),
inflateRaw: createConvenienceMethod(InflateRaw, false),
inflateRawSync: createConvenienceMethod(InflateRaw, true)
};
Object.defineProperties(module.exports, {
createDeflate: createProperty(module.exports.Deflate),
createInflate: createProperty(module.exports.Inflate),
createDeflateRaw: createProperty(module.exports.DeflateRaw),
createInflateRaw: createProperty(module.exports.InflateRaw),
createGzip: createProperty(module.exports.Gzip),
createGunzip: createProperty(module.exports.Gunzip),
createUnzip: createProperty(module.exports.Unzip),
constants: {
configurable: false,
enumerable: true,
value: constants
},
codes: {
enumerable: true,
writable: false,
value: Object.freeze(codes)
}
});
// These should be considered deprecated
// expose all the zlib constants
const bkeys = Object.keys(constants);
for (var bk = 0; bk < bkeys.length; bk++) {
var bkey = bkeys[bk];
Object.defineProperty(module.exports, bkey, {
enumerable: true, value: constants[bkey], writable: false
});
}
|