All files / lib/internal/streams writable.js

99.08% Statements 864/872
95.89% Branches 280/292
100% Functions 44/44
99.08% Lines 864/872

Press n or j to go to the next uncovered block, b, p or k for the previous block.

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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 87326x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 26x 241286x 26x 26x 26x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 83635x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 87893x 26x 105588x 105588x 105588x 105588x 105588x 105588x 26x 26x 51x 26x 26x 26x 26x 11x 11x 26x 26x 87910x 87910x 87910x 87910x 87910x 87910x 87910x 87910x 87910x 87910x 87910x 87910x 87910x 87910x 87910x 87893x 87893x 87893x 87910x 65683x 65683x 65683x 65683x 65683x 65683x 65683x 65683x 65683x 65683x 65683x 65683x 65683x 65683x 65683x 65683x 65683x 87886x 87886x 87886x 87886x 67x 67x 67x 67x 67x 67x 67x 87886x 87910x 26x 26x 26x 860x 19x 5x 860x 26x 26x 26x 26x 26x 1x 26x 26x 356798x 356798x 356798x 356798x 29963x 29963x 352211x 326835x 326835x 36058x 36058x 326833x 326833x 326835x 356796x 356798x 7x 356798x 353628x 90964x 29121x 29121x 29121x 353613x 262637x 262664x 6x 6x 27x 21x 21x 21x 353628x 356768x 356768x 356779x 21x 356785x 12x 12x 356768x 356779x 33x 33x 33x 33x 356735x 356735x 356798x 26x 26x 353503x 26x 26x 26x 39723x 26x 26x 26x 40517x 40517x 40517x 39784x 39784x 39784x 39784x 39784x 26x 26x 26x 8x 8x 8x 8x 8x 7x 7x 26x 26x 26x 26x 26x 356735x 356735x 356735x 356735x 356735x 356735x 356735x 356735x 356735x 356735x 356735x 356735x 125245x 125245x 15963x 15963x 125245x 16065x 16065x 356669x 231490x 231490x 231490x 231490x 231490x 231490x 231490x 356723x 356723x 356723x 356735x 356735x 26x 20982x 20982x 20982x 20982x 20982x 20982x 20982x 20982x 20982x 7860x 7860x 20979x 20982x 26x 55x 55x 55x 55x 55x 55x 55x 55x 55x 55x 55x 55x 26x 251863x 251863x 251863x 251863x 251863x 251863x 6x 6x 6x 251857x 251857x 251857x 251857x 251857x 251857x 251863x 55x 55x 55x 55x 54x 54x 55x 55x 55x 55x 25x 25x 55x 55x 30x 47x 25x 25x 251863x 251802x 17576x 17576x 251802x 251802x 224769x 224769x 224769x 224769x 224769x 224769x 180683x 224575x 44086x 44086x 44086x 251802x 27033x 27033x 251802x 251863x 26x 43942x 43942x 43942x 43942x 26x 70974x 70974x 70974x 70974x 25046x 25046x 25046x 70974x 70974x 251391x 251391x 251391x 70971x 70973x 414x 414x 70971x 70971x 70974x 26x 26x 477x 477x 5x 5x 472x 477x 13x 13x 13x 13x 13x 472x 472x 477x 8x 8x 472x 472x 477x 26x 26x 57412x 57412x 57412x 57412x 57412x 12956x 12956x 44456x 44456x 44456x 44456x 57411x 23499x 23499x 20957x 20957x 20957x 20957x 57412x 13122x 13122x 13122x 12666x 70016x 70016x 13122x 13122x 13122x 13122x 13122x 13122x 13122x 13122x 13122x 13122x 36349x 7835x 7860x 7860x 7860x 7860x 7835x 7835x 7835x 4108x 7827x     3724x 3724x 3724x 7835x 20954x 57412x 26x 26x 5276x 5275x 5276x 1x 1x 26x 26x 26x 26x 26x 32651x 32651x 32651x 651x 651x 651x 32472x 1023x 1023x 1023x 32651x 32651x 32651x 32651x 3295x 3295x 2x 2x 3295x 32649x 32649x 32650x 679x 679x 679x 32649x 32651x 2x 32651x 32087x 32087x 32087x 32087x 32087x 32087x 32087x 32087x 32087x 32641x 28x 557x 85x 85x 32649x 32651x 1676x 4x 1674x 1672x 1672x 1676x 32649x 32649x 26x 26x 135148x 135148x 135148x 135148x 135148x 135148x 135148x 135148x 135148x 26x 31488x 31488x 31488x 31488x 31453x 31453x 5x 5x     5x 31453x 31447x 31447x 31447x 31447x 31447x 31447x 31447x 31447x 31488x 31488x 18x 18x 18x 3x 3x 3x 2x 2x 1x 1x 1x 1x 3x 3x 1x 1x     1x 3x 3x 18x     18x 31488x 31488x 26x 34989x 34989x 32062x 31488x 31488x 32052x 574x 574x 574x 32062x 34989x 26x 103124x 103124x 34989x 34989x 572x 572x 98x 566x 474x 474x 572x 34989x 103124x 26x 32020x 32020x 32020x 32020x 32020x 31769x 31769x 31769x 31769x 32020x 1654x 1654x 31769x 31769x 31769x 31997x 8482x 8482x 8482x 8482x 8310x 8310x 8310x 8310x 8482x 8482x 3549x 3549x 8482x 32020x 26x 26x 26x 26x 26x 29554x 26x 26x 2x 2x 1x 1x 2x 26x 26x 26x 26x 116315x 116315x 116315x 116315x 116315x 116315x 116315x 26x 26x 12857x 12857x 12857x 12857x 12857x 26x 26x 26x 26x 54060x 54060x 26x 26x 26x 26x 3x 3x 26x 26x 26x 26x 52x 52x 26x 26x 26x 26x 11659x 11659x 26x 26x 26x 26x 2016x 2016x 2016x 2016x 26x 26x 26x 26x 57138x 57138x 26x 26x 26x 26x 6338x 6338x 26x 26x 26x 26x 8872x 8872x 26x 26x 26x 26x 26x 308x 308x 308x 308x 277x 308x 8x 8x 308x 308x 308x 26x 26x 26x 26x 198x 26x 26x 26x 2x 26x  
// 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.
 
// A bit simpler than readable streams.
// Implement an async ._write(chunk, encoding, cb), and it'll handle all
// the drain event emission and buffering.
 
'use strict';
 
const {
  ArrayPrototypeSlice,
  Error,
  FunctionPrototypeSymbolHasInstance,
  ObjectDefineProperty,
  ObjectDefineProperties,
  ObjectSetPrototypeOf,
  StringPrototypeToLowerCase,
  Symbol,
  SymbolHasInstance,
} = primordials;
 
module.exports = Writable;
Writable.WritableState = WritableState;
 
const EE = require('events');
const Stream = require('internal/streams/legacy').Stream;
const { Buffer } = require('buffer');
const destroyImpl = require('internal/streams/destroy');
 
const {
  addAbortSignalNoValidate,
} = require('internal/streams/add-abort-signal');
 
const {
  getHighWaterMark,
  getDefaultHighWaterMark
} = require('internal/streams/state');
const {
  ERR_INVALID_ARG_TYPE,
  ERR_METHOD_NOT_IMPLEMENTED,
  ERR_MULTIPLE_CALLBACK,
  ERR_STREAM_CANNOT_PIPE,
  ERR_STREAM_DESTROYED,
  ERR_STREAM_ALREADY_FINISHED,
  ERR_STREAM_NULL_VALUES,
  ERR_STREAM_WRITE_AFTER_END,
  ERR_UNKNOWN_ENCODING
} = require('internal/errors').codes;
 
const { errorOrDestroy } = destroyImpl;
 
ObjectSetPrototypeOf(Writable.prototype, Stream.prototype);
ObjectSetPrototypeOf(Writable, Stream);
 
function nop() {}
 
const kOnFinished = Symbol('kOnFinished');
 
function WritableState(options, stream, isDuplex) {
  // Duplex streams are both readable and writable, but share
  // the same options object.
  // However, some cases require setting options to different
  // values for the readable and the writable sides of the duplex stream,
  // e.g. options.readableObjectMode vs. options.writableObjectMode, etc.
  if (typeof isDuplex !== 'boolean')
    isDuplex = stream instanceof Stream.Duplex;
 
  // Object stream flag to indicate whether or not this stream
  // contains buffers or objects.
  this.objectMode = !!(options && options.objectMode);
 
  if (isDuplex)
    this.objectMode = this.objectMode ||
      !!(options && options.writableObjectMode);
 
  // The point at which write() starts returning false
  // Note: 0 is a valid value, means that we always return false if
  // the entire buffer is not flushed immediately on write().
  this.highWaterMark = options ?
    getHighWaterMark(this, options, 'writableHighWaterMark', isDuplex) :
    getDefaultHighWaterMark(false);
 
  // if _final has been called.
  this.finalCalled = false;
 
  // drain event flag.
  this.needDrain = false;
  // At the start of calling end()
  this.ending = false;
  // When end() has been called, and returned.
  this.ended = false;
  // When 'finish' is emitted.
  this.finished = false;
 
  // Has it been destroyed
  this.destroyed = false;
 
  // Should we decode strings into buffers before passing to _write?
  // this is here so that some node-core streams can optimize string
  // handling at a lower level.
  const noDecode = !!(options && options.decodeStrings === false);
  this.decodeStrings = !noDecode;
 
  // Crypto is kind of old and crusty.  Historically, its default string
  // encoding is 'binary' so we have to make this configurable.
  // Everything else in the universe uses 'utf8', though.
  this.defaultEncoding = (options && options.defaultEncoding) || 'utf8';
 
  // Not an actual buffer we keep track of, but a measurement
  // of how much we're waiting to get pushed to some underlying
  // socket or file.
  this.length = 0;
 
  // A flag to see when we're in the middle of a write.
  this.writing = false;
 
  // When true all writes will be buffered until .uncork() call.
  this.corked = 0;
 
  // A flag to be able to tell if the onwrite cb is called immediately,
  // or on a later tick.  We set this to true at first, because any
  // actions that shouldn't happen until "later" should generally also
  // not happen before the first write call.
  this.sync = true;
 
  // A flag to know if we're processing previously buffered items, which
  // may call the _write() callback in the same tick, so that we don't
  // end up in an overlapped onwrite situation.
  this.bufferProcessing = false;
 
  // The callback that's passed to _write(chunk, cb).
  this.onwrite = onwrite.bind(undefined, stream);
 
  // The callback that the user supplies to write(chunk, encoding, cb).
  this.writecb = null;
 
  // The amount that is being written when _write is called.
  this.writelen = 0;
 
  // Storage for data passed to the afterWrite() callback in case of
  // synchronous _write() completion.
  this.afterWriteTickInfo = null;
 
  resetBuffer(this);
 
  // Number of pending user-supplied write callbacks
  // this must be 0 before 'finish' can be emitted.
  this.pendingcb = 0;
 
  // Stream is still being constructed and cannot be
  // destroyed until construction finished or failed.
  // Async construction is opt in, therefore we start as
  // constructed.
  this.constructed = true;
 
  // Emit prefinish if the only thing we're waiting for is _write cbs
  // This is relevant for synchronous Transform streams.
  this.prefinished = false;
 
  // True if the error was already emitted and should not be thrown again.
  this.errorEmitted = false;
 
  // Should close be emitted on destroy. Defaults to true.
  this.emitClose = !options || options.emitClose !== false;
 
  // Should .destroy() be called after 'finish' (and potentially 'end').
  this.autoDestroy = !options || options.autoDestroy !== false;
 
  // Indicates whether the stream has errored. When true all write() calls
  // should return false. This is needed since when autoDestroy
  // is disabled we need a way to tell whether the stream has failed.
  this.errored = null;
 
  // Indicates whether the stream has finished destroying.
  this.closed = false;
 
  // True if close has been emitted or would have been emitted
  // depending on emitClose.
  this.closeEmitted = false;
 
  this[kOnFinished] = [];
}
 
function resetBuffer(state) {
  state.buffered = [];
  state.bufferedIndex = 0;
  state.allBuffers = true;
  state.allNoop = true;
}
 
WritableState.prototype.getBuffer = function getBuffer() {
  return ArrayPrototypeSlice(this.buffered, this.bufferedIndex);
};
 
ObjectDefineProperty(WritableState.prototype, 'bufferedRequestCount', {
  get() {
    return this.buffered.length - this.bufferedIndex;
  }
});
 
function Writable(options) {
  // Writable ctor is applied to Duplexes, too.
  // `realHasInstance` is necessary because using plain `instanceof`
  // would return false, as no `_writableState` property is attached.
 
  // Trying to use the custom `instanceof` for Writable here will also break the
  // Node.js LazyTransform implementation, which has a non-trivial getter for
  // `_writableState` that would lead to infinite recursion.
 
  // Checking for a Stream.Duplex instance is faster here instead of inside
  // the WritableState constructor, at least with V8 6.5.
  const isDuplex = (this instanceof Stream.Duplex);
 
  if (!isDuplex && !FunctionPrototypeSymbolHasInstance(Writable, this))
    return new Writable(options);
 
  this._writableState = new WritableState(options, this, isDuplex);
 
  if (options) {
    if (typeof options.write === 'function')
      this._write = options.write;
 
    if (typeof options.writev === 'function')
      this._writev = options.writev;
 
    if (typeof options.destroy === 'function')
      this._destroy = options.destroy;
 
    if (typeof options.final === 'function')
      this._final = options.final;
 
    if (typeof options.construct === 'function')
      this._construct = options.construct;
    if (options.signal)
      addAbortSignalNoValidate(options.signal, this);
  }
 
  Stream.call(this, options);
 
  destroyImpl.construct(this, () => {
    const state = this._writableState;
 
    if (!state.writing) {
      clearBuffer(this, state);
    }
 
    finishMaybe(this, state);
  });
}
 
ObjectDefineProperty(Writable, SymbolHasInstance, {
  value: function(object) {
    if (FunctionPrototypeSymbolHasInstance(this, object)) return true;
    if (this !== Writable) return false;
 
    return object && object._writableState instanceof WritableState;
  },
});
 
// Otherwise people can pipe Writable streams, which is just wrong.
Writable.prototype.pipe = function() {
  errorOrDestroy(this, new ERR_STREAM_CANNOT_PIPE());
};
 
function _write(stream, chunk, encoding, cb) {
  const state = stream._writableState;
 
  if (typeof encoding === 'function') {
    cb = encoding;
    encoding = state.defaultEncoding;
  } else {
    if (!encoding)
      encoding = state.defaultEncoding;
    else if (encoding !== 'buffer' && !Buffer.isEncoding(encoding))
      throw new ERR_UNKNOWN_ENCODING(encoding);
    if (typeof cb !== 'function')
      cb = nop;
  }
 
  if (chunk === null) {
    throw new ERR_STREAM_NULL_VALUES();
  } else if (!state.objectMode) {
    if (typeof chunk === 'string') {
      if (state.decodeStrings !== false) {
        chunk = Buffer.from(chunk, encoding);
        encoding = 'buffer';
      }
    } else if (chunk instanceof Buffer) {
      encoding = 'buffer';
    } else if (Stream._isUint8Array(chunk)) {
      chunk = Stream._uint8ArrayToBuffer(chunk);
      encoding = 'buffer';
    } else {
      throw new ERR_INVALID_ARG_TYPE(
        'chunk', ['string', 'Buffer', 'Uint8Array'], chunk);
    }
  }
 
  let err;
  if (state.ending) {
    err = new ERR_STREAM_WRITE_AFTER_END();
  } else if (state.destroyed) {
    err = new ERR_STREAM_DESTROYED('write');
  }
 
  if (err) {
    process.nextTick(cb, err);
    errorOrDestroy(stream, err, true);
    return err;
  }
  state.pendingcb++;
  return writeOrBuffer(stream, state, chunk, encoding, cb);
}
 
Writable.prototype.write = function(chunk, encoding, cb) {
  return _write(this, chunk, encoding, cb) === true;
};
 
Writable.prototype.cork = function() {
  this._writableState.corked++;
};
 
Writable.prototype.uncork = function() {
  const state = this._writableState;
 
  if (state.corked) {
    state.corked--;
 
    if (!state.writing)
      clearBuffer(this, state);
  }
};
 
Writable.prototype.setDefaultEncoding = function setDefaultEncoding(encoding) {
  // node::ParseEncoding() requires lower case.
  if (typeof encoding === 'string')
    encoding = StringPrototypeToLowerCase(encoding);
  if (!Buffer.isEncoding(encoding))
    throw new ERR_UNKNOWN_ENCODING(encoding);
  this._writableState.defaultEncoding = encoding;
  return this;
};
 
// If we're already writing something, then just put this
// in the queue, and wait our turn.  Otherwise, call _write
// If we return false, then we need a drain event, so set that flag.
function writeOrBuffer(stream, state, chunk, encoding, callback) {
  const len = state.objectMode ? 1 : chunk.length;
 
  state.length += len;
 
  // stream._write resets state.length
  const ret = state.length < state.highWaterMark;
  // We must ensure that previous needDrain will not be reset to false.
  if (!ret)
    state.needDrain = true;
 
  if (state.writing || state.corked || state.errored || !state.constructed) {
    state.buffered.push({ chunk, encoding, callback });
    if (state.allBuffers && encoding !== 'buffer') {
      state.allBuffers = false;
    }
    if (state.allNoop && callback !== nop) {
      state.allNoop = false;
    }
  } else {
    state.writelen = len;
    state.writecb = callback;
    state.writing = true;
    state.sync = true;
    stream._write(chunk, encoding, state.onwrite);
    state.sync = false;
  }
 
  // Return false if errored or destroyed in order to break
  // any synchronous while(stream.write(data)) loops.
  return ret && !state.errored && !state.destroyed;
}
 
function doWrite(stream, state, writev, len, chunk, encoding, cb) {
  state.writelen = len;
  state.writecb = cb;
  state.writing = true;
  state.sync = true;
  if (state.destroyed)
    state.onwrite(new ERR_STREAM_DESTROYED('write'));
  else if (writev)
    stream._writev(chunk, state.onwrite);
  else
    stream._write(chunk, encoding, state.onwrite);
  state.sync = false;
}
 
function onwriteError(stream, state, er, cb) {
  --state.pendingcb;
 
  cb(er);
  // Ensure callbacks are invoked even when autoDestroy is
  // not enabled. Passing `er` here doesn't make sense since
  // it's related to one specific write, not to the buffered
  // writes.
  errorBuffer(state);
  // This can emit error, but error must always follow cb.
  errorOrDestroy(stream, er);
}
 
function onwrite(stream, er) {
  const state = stream._writableState;
  const sync = state.sync;
  const cb = state.writecb;
 
  if (typeof cb !== 'function') {
    errorOrDestroy(stream, new ERR_MULTIPLE_CALLBACK());
    return;
  }
 
  state.writing = false;
  state.writecb = null;
  state.length -= state.writelen;
  state.writelen = 0;
 
  if (er) {
    // Avoid V8 leak, https://github.com/nodejs/node/pull/34103#issuecomment-652002364
    er.stack; // eslint-disable-line no-unused-expressions
 
    if (!state.errored) {
      state.errored = er;
    }
 
    // In case of duplex streams we need to notify the readable side of the
    // error.
    if (stream._readableState && !stream._readableState.errored) {
      stream._readableState.errored = er;
    }
 
    if (sync) {
      process.nextTick(onwriteError, stream, state, er, cb);
    } else {
      onwriteError(stream, state, er, cb);
    }
  } else {
    if (state.buffered.length > state.bufferedIndex) {
      clearBuffer(stream, state);
    }
 
    if (sync) {
      // It is a common case that the callback passed to .write() is always
      // the same. In that case, we do not schedule a new nextTick(), but
      // rather just increase a counter, to improve performance and avoid
      // memory allocations.
      if (state.afterWriteTickInfo !== null &&
          state.afterWriteTickInfo.cb === cb) {
        state.afterWriteTickInfo.count++;
      } else {
        state.afterWriteTickInfo = { count: 1, cb, stream, state };
        process.nextTick(afterWriteTick, state.afterWriteTickInfo);
      }
    } else {
      afterWrite(stream, state, 1, cb);
    }
  }
}
 
function afterWriteTick({ stream, state, count, cb }) {
  state.afterWriteTickInfo = null;
  return afterWrite(stream, state, count, cb);
}
 
function afterWrite(stream, state, count, cb) {
  const needDrain = !state.ending && !stream.destroyed && state.length === 0 &&
    state.needDrain;
  if (needDrain) {
    state.needDrain = false;
    stream.emit('drain');
  }
 
  while (count-- > 0) {
    state.pendingcb--;
    cb();
  }
 
  if (state.destroyed) {
    errorBuffer(state);
  }
 
  finishMaybe(stream, state);
}
 
// If there's something in the buffer waiting, then invoke callbacks.
function errorBuffer(state) {
  if (state.writing) {
    return;
  }
 
  for (let n = state.bufferedIndex; n < state.buffered.length; ++n) {
    const { chunk, callback } = state.buffered[n];
    const len = state.objectMode ? 1 : chunk.length;
    state.length -= len;
    callback(new ERR_STREAM_DESTROYED('write'));
  }
 
  const onfinishCallbacks = state[kOnFinished].splice(0);
  for (let i = 0; i < onfinishCallbacks.length; i++) {
    onfinishCallbacks[i](new ERR_STREAM_DESTROYED('end'));
  }
 
  resetBuffer(state);
}
 
// If there's something in the buffer waiting, then process it.
function clearBuffer(stream, state) {
  if (state.corked ||
      state.bufferProcessing ||
      state.destroyed ||
      !state.constructed) {
    return;
  }
 
  const { buffered, bufferedIndex, objectMode } = state;
  const bufferedLength = buffered.length - bufferedIndex;
 
  if (!bufferedLength) {
    return;
  }
 
  let i = bufferedIndex;
 
  state.bufferProcessing = true;
  if (bufferedLength > 1 && stream._writev) {
    state.pendingcb -= bufferedLength - 1;
 
    const callback = state.allNoop ? nop : (err) => {
      for (let n = i; n < buffered.length; ++n) {
        buffered[n].callback(err);
      }
    };
    // Make a copy of `buffered` if it's going to be used by `callback` above,
    // since `doWrite` will mutate the array.
    const chunks = state.allNoop && i === 0 ?
      buffered : ArrayPrototypeSlice(buffered, i);
    chunks.allBuffers = state.allBuffers;
 
    doWrite(stream, state, true, state.length, chunks, '', callback);
 
    resetBuffer(state);
  } else {
    do {
      const { chunk, encoding, callback } = buffered[i];
      buffered[i++] = null;
      const len = objectMode ? 1 : chunk.length;
      doWrite(stream, state, false, len, chunk, encoding, callback);
    } while (i < buffered.length && !state.writing);
 
    if (i === buffered.length) {
      resetBuffer(state);
    } else if (i > 256) {
      buffered.splice(0, i);
      state.bufferedIndex = 0;
    } else {
      state.bufferedIndex = i;
    }
  }
  state.bufferProcessing = false;
}
 
Writable.prototype._write = function(chunk, encoding, cb) {
  if (this._writev) {
    this._writev([{ chunk, encoding }], cb);
  } else {
    throw new ERR_METHOD_NOT_IMPLEMENTED('_write()');
  }
};
 
Writable.prototype._writev = null;
 
Writable.prototype.end = function(chunk, encoding, cb) {
  const state = this._writableState;
 
  if (typeof chunk === 'function') {
    cb = chunk;
    chunk = null;
    encoding = null;
  } else if (typeof encoding === 'function') {
    cb = encoding;
    encoding = null;
  }
 
  let err;
 
  if (chunk !== null && chunk !== undefined) {
    const ret = _write(this, chunk, encoding);
    if (ret instanceof Error) {
      err = ret;
    }
  }
 
  // .end() fully uncorks.
  if (state.corked) {
    state.corked = 1;
    this.uncork();
  }
 
  if (err) {
    // Do nothing...
  } else if (!state.errored && !state.ending) {
    // This is forgiving in terms of unnecessary calls to end() and can hide
    // logic errors. However, usually such errors are harmless and causing a
    // hard error can be disproportionately destructive. It is not always
    // trivial for the user to determine whether end() needs to be called
    // or not.
 
    state.ending = true;
    finishMaybe(this, state, true);
    state.ended = true;
  } else if (state.finished) {
    err = new ERR_STREAM_ALREADY_FINISHED('end');
  } else if (state.destroyed) {
    err = new ERR_STREAM_DESTROYED('end');
  }
 
  if (typeof cb === 'function') {
    if (err || state.finished) {
      process.nextTick(cb, err);
    } else {
      state[kOnFinished].push(cb);
    }
  }
 
  return this;
};
 
function needFinish(state) {
  return (state.ending &&
          state.constructed &&
          state.length === 0 &&
          !state.errored &&
          state.buffered.length === 0 &&
          !state.finished &&
          !state.writing);
}
 
function callFinal(stream, state) {
  state.sync = true;
  state.pendingcb++;
  const result = stream._final((err) => {
    state.pendingcb--;
    if (err) {
      const onfinishCallbacks = state[kOnFinished].splice(0);
      for (let i = 0; i < onfinishCallbacks.length; i++) {
        onfinishCallbacks[i](err);
      }
      errorOrDestroy(stream, err, state.sync);
    } else if (needFinish(state)) {
      state.prefinished = true;
      stream.emit('prefinish');
      // Backwards compat. Don't check state.sync here.
      // Some streams assume 'finish' will be emitted
      // asynchronously relative to _final callback.
      state.pendingcb++;
      process.nextTick(finish, stream, state);
    }
  });
  if (result !== undefined && result !== null) {
    try {
      const then = result.then;
      if (typeof then === 'function') {
        then.call(
          result,
          function() {
            if (state.prefinished)
              return;
            state.prefinish = true;
            process.nextTick(() => stream.emit('prefinish'));
            state.pendingcb++;
            process.nextTick(finish, stream, state);
          },
          function(err) {
            const onfinishCallbacks = state[kOnFinished].splice(0);
            for (let i = 0; i < onfinishCallbacks.length; i++) {
              process.nextTick(onfinishCallbacks[i], err);
            }
            process.nextTick(errorOrDestroy, stream, err, state.sync);
          });
      }
    } catch (err) {
      process.nextTick(errorOrDestroy, stream, err, state.sync);
    }
  }
  state.sync = false;
}
 
function prefinish(stream, state) {
  if (!state.prefinished && !state.finalCalled) {
    if (typeof stream._final === 'function' && !state.destroyed) {
      state.finalCalled = true;
      callFinal(stream, state);
    } else {
      state.prefinished = true;
      stream.emit('prefinish');
    }
  }
}
 
function finishMaybe(stream, state, sync) {
  if (needFinish(state)) {
    prefinish(stream, state);
    if (state.pendingcb === 0 && needFinish(state)) {
      state.pendingcb++;
      if (sync) {
        process.nextTick(finish, stream, state);
      } else {
        finish(stream, state);
      }
    }
  }
}
 
function finish(stream, state) {
  state.pendingcb--;
  // TODO (ronag): Unify with needFinish.
  if (state.errorEmitted || state.closeEmitted)
    return;
 
  state.finished = true;
 
  const onfinishCallbacks = state[kOnFinished].splice(0);
  for (let i = 0; i < onfinishCallbacks.length; i++) {
    onfinishCallbacks[i]();
  }
 
  stream.emit('finish');
 
  if (state.autoDestroy) {
    // In case of duplex streams we need a way to detect
    // if the readable side is ready for autoDestroy as well.
    const rState = stream._readableState;
    const autoDestroy = !rState || (
      rState.autoDestroy &&
      // We don't expect the readable to ever 'end'
      // if readable is explicitly set to false.
      (rState.endEmitted || rState.readable === false)
    );
    if (autoDestroy) {
      stream.destroy();
    }
  }
}
 
ObjectDefineProperties(Writable.prototype, {
 
  destroyed: {
    get() {
      return this._writableState ? this._writableState.destroyed : false;
    },
    set(value) {
      // Backward compatibility, the user is explicitly managing destroyed.
      if (this._writableState) {
        this._writableState.destroyed = value;
      }
    }
  },
 
  writable: {
    get() {
      const w = this._writableState;
      // w.writable === false means that this is part of a Duplex stream
      // where the writable side was disabled upon construction.
      // Compat. The user might manually disable writable side through
      // deprecated setter.
      return !!w && w.writable !== false && !w.destroyed && !w.errored &&
        !w.ending && !w.ended;
    },
    set(val) {
      // Backwards compatible.
      if (this._writableState) {
        this._writableState.writable = !!val;
      }
    }
  },
 
  writableFinished: {
    get() {
      return this._writableState ? this._writableState.finished : false;
    }
  },
 
  writableObjectMode: {
    get() {
      return this._writableState ? this._writableState.objectMode : false;
    }
  },
 
  writableBuffer: {
    get() {
      return this._writableState && this._writableState.getBuffer();
    }
  },
 
  writableEnded: {
    get() {
      return this._writableState ? this._writableState.ending : false;
    }
  },
 
  writableNeedDrain: {
    get() {
      const wState = this._writableState;
      if (!wState) return false;
      return !wState.destroyed && !wState.ending && wState.needDrain;
    }
  },
 
  writableHighWaterMark: {
    get() {
      return this._writableState && this._writableState.highWaterMark;
    }
  },
 
  writableCorked: {
    get() {
      return this._writableState ? this._writableState.corked : 0;
    }
  },
 
  writableLength: {
    get() {
      return this._writableState && this._writableState.length;
    }
  }
});
 
const destroy = destroyImpl.destroy;
Writable.prototype.destroy = function(err, cb) {
  const state = this._writableState;
 
  // Invoke pending callbacks.
  if (!state.destroyed &&
    (state.bufferedIndex < state.buffered.length ||
      state[kOnFinished].length)) {
    process.nextTick(errorBuffer, state);
  }
 
  destroy.call(this, err, cb);
  return this;
};
 
Writable.prototype._undestroy = destroyImpl.undestroy;
Writable.prototype._destroy = function(err, cb) {
  cb(err);
};
 
Writable.prototype[EE.captureRejectionSymbol] = function(err) {
  this.destroy(err);
};