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1// Copyright Joyent, Inc. and other Node contributors.
2//
3// Permission is hereby granted, free of charge, to any person obtaining a
4// copy of this software and associated documentation files (the
5// "Software"), to deal in the Software without restriction, including
6// without limitation the rights to use, copy, modify, merge, publish,
7// distribute, sublicense, and/or sell copies of the Software, and to permit
8// persons to whom the Software is furnished to do so, subject to the
9// following conditions:
10//
11// The above copyright notice and this permission notice shall be included
12// in all copies or substantial portions of the Software.
13//
14// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
15// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
16// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
17// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
18// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
19// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
20// USE OR OTHER DEALINGS IN THE SOFTWARE.
21// A bit simpler than readable streams.
22// Implement an async ._write(chunk, encoding, cb), and it'll handle all
23// the drain event emission and buffering.
24'use strict';
25
26module.exports = Writable;
27/* <replacement> */
28
29function WriteReq(chunk, encoding, cb) {
30  this.chunk = chunk;
31  this.encoding = encoding;
32  this.callback = cb;
33  this.next = null;
34} // It seems a linked list but it is not
35// there will be only 2 of these for each stream
36
37
38function CorkedRequest(state) {
39  var _this = this;
40
41  this.next = null;
42  this.entry = null;
43
44  this.finish = function () {
45    onCorkedFinish(_this, state);
46  };
47}
48/* </replacement> */
49
50/*<replacement>*/
51
52
53var Duplex;
54/*</replacement>*/
55
56Writable.WritableState = WritableState;
57/*<replacement>*/
58
59var internalUtil = {
60  deprecate: require('util-deprecate')
61};
62/*</replacement>*/
63
64/*<replacement>*/
65
66var Stream = require('./internal/streams/stream');
67/*</replacement>*/
68
69
70var Buffer = require('buffer').Buffer;
71
72var OurUint8Array = global.Uint8Array || function () {};
73
74function _uint8ArrayToBuffer(chunk) {
75  return Buffer.from(chunk);
76}
77
78function _isUint8Array(obj) {
79  return Buffer.isBuffer(obj) || obj instanceof OurUint8Array;
80}
81
82var destroyImpl = require('./internal/streams/destroy');
83
84var _require = require('./internal/streams/state'),
85    getHighWaterMark = _require.getHighWaterMark;
86
87var _require$codes = require('../errors').codes,
88    ERR_INVALID_ARG_TYPE = _require$codes.ERR_INVALID_ARG_TYPE,
89    ERR_METHOD_NOT_IMPLEMENTED = _require$codes.ERR_METHOD_NOT_IMPLEMENTED,
90    ERR_MULTIPLE_CALLBACK = _require$codes.ERR_MULTIPLE_CALLBACK,
91    ERR_STREAM_CANNOT_PIPE = _require$codes.ERR_STREAM_CANNOT_PIPE,
92    ERR_STREAM_DESTROYED = _require$codes.ERR_STREAM_DESTROYED,
93    ERR_STREAM_NULL_VALUES = _require$codes.ERR_STREAM_NULL_VALUES,
94    ERR_STREAM_WRITE_AFTER_END = _require$codes.ERR_STREAM_WRITE_AFTER_END,
95    ERR_UNKNOWN_ENCODING = _require$codes.ERR_UNKNOWN_ENCODING;
96
97var errorOrDestroy = destroyImpl.errorOrDestroy;
98
99require('inherits')(Writable, Stream);
100
101function nop() {}
102
103function WritableState(options, stream, isDuplex) {
104  Duplex = Duplex || require('./_stream_duplex');
105  options = options || {}; // Duplex streams are both readable and writable, but share
106  // the same options object.
107  // However, some cases require setting options to different
108  // values for the readable and the writable sides of the duplex stream,
109  // e.g. options.readableObjectMode vs. options.writableObjectMode, etc.
110
111  if (typeof isDuplex !== 'boolean') isDuplex = stream instanceof Duplex; // object stream flag to indicate whether or not this stream
112  // contains buffers or objects.
113
114  this.objectMode = !!options.objectMode;
115  if (isDuplex) this.objectMode = this.objectMode || !!options.writableObjectMode; // the point at which write() starts returning false
116  // Note: 0 is a valid value, means that we always return false if
117  // the entire buffer is not flushed immediately on write()
118
119  this.highWaterMark = getHighWaterMark(this, options, 'writableHighWaterMark', isDuplex); // if _final has been called
120
121  this.finalCalled = false; // drain event flag.
122
123  this.needDrain = false; // at the start of calling end()
124
125  this.ending = false; // when end() has been called, and returned
126
127  this.ended = false; // when 'finish' is emitted
128
129  this.finished = false; // has it been destroyed
130
131  this.destroyed = false; // should we decode strings into buffers before passing to _write?
132  // this is here so that some node-core streams can optimize string
133  // handling at a lower level.
134
135  var noDecode = options.decodeStrings === false;
136  this.decodeStrings = !noDecode; // Crypto is kind of old and crusty.  Historically, its default string
137  // encoding is 'binary' so we have to make this configurable.
138  // Everything else in the universe uses 'utf8', though.
139
140  this.defaultEncoding = options.defaultEncoding || 'utf8'; // not an actual buffer we keep track of, but a measurement
141  // of how much we're waiting to get pushed to some underlying
142  // socket or file.
143
144  this.length = 0; // a flag to see when we're in the middle of a write.
145
146  this.writing = false; // when true all writes will be buffered until .uncork() call
147
148  this.corked = 0; // a flag to be able to tell if the onwrite cb is called immediately,
149  // or on a later tick.  We set this to true at first, because any
150  // actions that shouldn't happen until "later" should generally also
151  // not happen before the first write call.
152
153  this.sync = true; // a flag to know if we're processing previously buffered items, which
154  // may call the _write() callback in the same tick, so that we don't
155  // end up in an overlapped onwrite situation.
156
157  this.bufferProcessing = false; // the callback that's passed to _write(chunk,cb)
158
159  this.onwrite = function (er) {
160    onwrite(stream, er);
161  }; // the callback that the user supplies to write(chunk,encoding,cb)
162
163
164  this.writecb = null; // the amount that is being written when _write is called.
165
166  this.writelen = 0;
167  this.bufferedRequest = null;
168  this.lastBufferedRequest = null; // number of pending user-supplied write callbacks
169  // this must be 0 before 'finish' can be emitted
170
171  this.pendingcb = 0; // emit prefinish if the only thing we're waiting for is _write cbs
172  // This is relevant for synchronous Transform streams
173
174  this.prefinished = false; // True if the error was already emitted and should not be thrown again
175
176  this.errorEmitted = false; // Should close be emitted on destroy. Defaults to true.
177
178  this.emitClose = options.emitClose !== false; // Should .destroy() be called after 'finish' (and potentially 'end')
179
180  this.autoDestroy = !!options.autoDestroy; // count buffered requests
181
182  this.bufferedRequestCount = 0; // allocate the first CorkedRequest, there is always
183  // one allocated and free to use, and we maintain at most two
184
185  this.corkedRequestsFree = new CorkedRequest(this);
186}
187
188WritableState.prototype.getBuffer = function getBuffer() {
189  var current = this.bufferedRequest;
190  var out = [];
191
192  while (current) {
193    out.push(current);
194    current = current.next;
195  }
196
197  return out;
198};
199
200(function () {
201  try {
202    Object.defineProperty(WritableState.prototype, 'buffer', {
203      get: internalUtil.deprecate(function writableStateBufferGetter() {
204        return this.getBuffer();
205      }, '_writableState.buffer is deprecated. Use _writableState.getBuffer ' + 'instead.', 'DEP0003')
206    });
207  } catch (_) {}
208})(); // Test _writableState for inheritance to account for Duplex streams,
209// whose prototype chain only points to Readable.
210
211
212var realHasInstance;
213
214if (typeof Symbol === 'function' && Symbol.hasInstance && typeof Function.prototype[Symbol.hasInstance] === 'function') {
215  realHasInstance = Function.prototype[Symbol.hasInstance];
216  Object.defineProperty(Writable, Symbol.hasInstance, {
217    value: function value(object) {
218      if (realHasInstance.call(this, object)) return true;
219      if (this !== Writable) return false;
220      return object && object._writableState instanceof WritableState;
221    }
222  });
223} else {
224  realHasInstance = function realHasInstance(object) {
225    return object instanceof this;
226  };
227}
228
229function Writable(options) {
230  Duplex = Duplex || require('./_stream_duplex'); // Writable ctor is applied to Duplexes, too.
231  // `realHasInstance` is necessary because using plain `instanceof`
232  // would return false, as no `_writableState` property is attached.
233  // Trying to use the custom `instanceof` for Writable here will also break the
234  // Node.js LazyTransform implementation, which has a non-trivial getter for
235  // `_writableState` that would lead to infinite recursion.
236  // Checking for a Stream.Duplex instance is faster here instead of inside
237  // the WritableState constructor, at least with V8 6.5
238
239  var isDuplex = this instanceof Duplex;
240  if (!isDuplex && !realHasInstance.call(Writable, this)) return new Writable(options);
241  this._writableState = new WritableState(options, this, isDuplex); // legacy.
242
243  this.writable = true;
244
245  if (options) {
246    if (typeof options.write === 'function') this._write = options.write;
247    if (typeof options.writev === 'function') this._writev = options.writev;
248    if (typeof options.destroy === 'function') this._destroy = options.destroy;
249    if (typeof options.final === 'function') this._final = options.final;
250  }
251
252  Stream.call(this);
253} // Otherwise people can pipe Writable streams, which is just wrong.
254
255
256Writable.prototype.pipe = function () {
257  errorOrDestroy(this, new ERR_STREAM_CANNOT_PIPE());
258};
259
260function writeAfterEnd(stream, cb) {
261  var er = new ERR_STREAM_WRITE_AFTER_END(); // TODO: defer error events consistently everywhere, not just the cb
262
263  errorOrDestroy(stream, er);
264  process.nextTick(cb, er);
265} // Checks that a user-supplied chunk is valid, especially for the particular
266// mode the stream is in. Currently this means that `null` is never accepted
267// and undefined/non-string values are only allowed in object mode.
268
269
270function validChunk(stream, state, chunk, cb) {
271  var er;
272
273  if (chunk === null) {
274    er = new ERR_STREAM_NULL_VALUES();
275  } else if (typeof chunk !== 'string' && !state.objectMode) {
276    er = new ERR_INVALID_ARG_TYPE('chunk', ['string', 'Buffer'], chunk);
277  }
278
279  if (er) {
280    errorOrDestroy(stream, er);
281    process.nextTick(cb, er);
282    return false;
283  }
284
285  return true;
286}
287
288Writable.prototype.write = function (chunk, encoding, cb) {
289  var state = this._writableState;
290  var ret = false;
291
292  var isBuf = !state.objectMode && _isUint8Array(chunk);
293
294  if (isBuf && !Buffer.isBuffer(chunk)) {
295    chunk = _uint8ArrayToBuffer(chunk);
296  }
297
298  if (typeof encoding === 'function') {
299    cb = encoding;
300    encoding = null;
301  }
302
303  if (isBuf) encoding = 'buffer';else if (!encoding) encoding = state.defaultEncoding;
304  if (typeof cb !== 'function') cb = nop;
305  if (state.ending) writeAfterEnd(this, cb);else if (isBuf || validChunk(this, state, chunk, cb)) {
306    state.pendingcb++;
307    ret = writeOrBuffer(this, state, isBuf, chunk, encoding, cb);
308  }
309  return ret;
310};
311
312Writable.prototype.cork = function () {
313  this._writableState.corked++;
314};
315
316Writable.prototype.uncork = function () {
317  var state = this._writableState;
318
319  if (state.corked) {
320    state.corked--;
321    if (!state.writing && !state.corked && !state.bufferProcessing && state.bufferedRequest) clearBuffer(this, state);
322  }
323};
324
325Writable.prototype.setDefaultEncoding = function setDefaultEncoding(encoding) {
326  // node::ParseEncoding() requires lower case.
327  if (typeof encoding === 'string') encoding = encoding.toLowerCase();
328  if (!(['hex', 'utf8', 'utf-8', 'ascii', 'binary', 'base64', 'ucs2', 'ucs-2', 'utf16le', 'utf-16le', 'raw'].indexOf((encoding + '').toLowerCase()) > -1)) throw new ERR_UNKNOWN_ENCODING(encoding);
329  this._writableState.defaultEncoding = encoding;
330  return this;
331};
332
333Object.defineProperty(Writable.prototype, 'writableBuffer', {
334  // making it explicit this property is not enumerable
335  // because otherwise some prototype manipulation in
336  // userland will fail
337  enumerable: false,
338  get: function get() {
339    return this._writableState && this._writableState.getBuffer();
340  }
341});
342
343function decodeChunk(state, chunk, encoding) {
344  if (!state.objectMode && state.decodeStrings !== false && typeof chunk === 'string') {
345    chunk = Buffer.from(chunk, encoding);
346  }
347
348  return chunk;
349}
350
351Object.defineProperty(Writable.prototype, 'writableHighWaterMark', {
352  // making it explicit this property is not enumerable
353  // because otherwise some prototype manipulation in
354  // userland will fail
355  enumerable: false,
356  get: function get() {
357    return this._writableState.highWaterMark;
358  }
359}); // if we're already writing something, then just put this
360// in the queue, and wait our turn.  Otherwise, call _write
361// If we return false, then we need a drain event, so set that flag.
362
363function writeOrBuffer(stream, state, isBuf, chunk, encoding, cb) {
364  if (!isBuf) {
365    var newChunk = decodeChunk(state, chunk, encoding);
366
367    if (chunk !== newChunk) {
368      isBuf = true;
369      encoding = 'buffer';
370      chunk = newChunk;
371    }
372  }
373
374  var len = state.objectMode ? 1 : chunk.length;
375  state.length += len;
376  var ret = state.length < state.highWaterMark; // we must ensure that previous needDrain will not be reset to false.
377
378  if (!ret) state.needDrain = true;
379
380  if (state.writing || state.corked) {
381    var last = state.lastBufferedRequest;
382    state.lastBufferedRequest = {
383      chunk: chunk,
384      encoding: encoding,
385      isBuf: isBuf,
386      callback: cb,
387      next: null
388    };
389
390    if (last) {
391      last.next = state.lastBufferedRequest;
392    } else {
393      state.bufferedRequest = state.lastBufferedRequest;
394    }
395
396    state.bufferedRequestCount += 1;
397  } else {
398    doWrite(stream, state, false, len, chunk, encoding, cb);
399  }
400
401  return ret;
402}
403
404function doWrite(stream, state, writev, len, chunk, encoding, cb) {
405  state.writelen = len;
406  state.writecb = cb;
407  state.writing = true;
408  state.sync = true;
409  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);
410  state.sync = false;
411}
412
413function onwriteError(stream, state, sync, er, cb) {
414  --state.pendingcb;
415
416  if (sync) {
417    // defer the callback if we are being called synchronously
418    // to avoid piling up things on the stack
419    process.nextTick(cb, er); // this can emit finish, and it will always happen
420    // after error
421
422    process.nextTick(finishMaybe, stream, state);
423    stream._writableState.errorEmitted = true;
424    errorOrDestroy(stream, er);
425  } else {
426    // the caller expect this to happen before if
427    // it is async
428    cb(er);
429    stream._writableState.errorEmitted = true;
430    errorOrDestroy(stream, er); // this can emit finish, but finish must
431    // always follow error
432
433    finishMaybe(stream, state);
434  }
435}
436
437function onwriteStateUpdate(state) {
438  state.writing = false;
439  state.writecb = null;
440  state.length -= state.writelen;
441  state.writelen = 0;
442}
443
444function onwrite(stream, er) {
445  var state = stream._writableState;
446  var sync = state.sync;
447  var cb = state.writecb;
448  if (typeof cb !== 'function') throw new ERR_MULTIPLE_CALLBACK();
449  onwriteStateUpdate(state);
450  if (er) onwriteError(stream, state, sync, er, cb);else {
451    // Check if we're actually ready to finish, but don't emit yet
452    var finished = needFinish(state) || stream.destroyed;
453
454    if (!finished && !state.corked && !state.bufferProcessing && state.bufferedRequest) {
455      clearBuffer(stream, state);
456    }
457
458    if (sync) {
459      process.nextTick(afterWrite, stream, state, finished, cb);
460    } else {
461      afterWrite(stream, state, finished, cb);
462    }
463  }
464}
465
466function afterWrite(stream, state, finished, cb) {
467  if (!finished) onwriteDrain(stream, state);
468  state.pendingcb--;
469  cb();
470  finishMaybe(stream, state);
471} // Must force callback to be called on nextTick, so that we don't
472// emit 'drain' before the write() consumer gets the 'false' return
473// value, and has a chance to attach a 'drain' listener.
474
475
476function onwriteDrain(stream, state) {
477  if (state.length === 0 && state.needDrain) {
478    state.needDrain = false;
479    stream.emit('drain');
480  }
481} // if there's something in the buffer waiting, then process it
482
483
484function clearBuffer(stream, state) {
485  state.bufferProcessing = true;
486  var entry = state.bufferedRequest;
487
488  if (stream._writev && entry && entry.next) {
489    // Fast case, write everything using _writev()
490    var l = state.bufferedRequestCount;
491    var buffer = new Array(l);
492    var holder = state.corkedRequestsFree;
493    holder.entry = entry;
494    var count = 0;
495    var allBuffers = true;
496
497    while (entry) {
498      buffer[count] = entry;
499      if (!entry.isBuf) allBuffers = false;
500      entry = entry.next;
501      count += 1;
502    }
503
504    buffer.allBuffers = allBuffers;
505    doWrite(stream, state, true, state.length, buffer, '', holder.finish); // doWrite is almost always async, defer these to save a bit of time
506    // as the hot path ends with doWrite
507
508    state.pendingcb++;
509    state.lastBufferedRequest = null;
510
511    if (holder.next) {
512      state.corkedRequestsFree = holder.next;
513      holder.next = null;
514    } else {
515      state.corkedRequestsFree = new CorkedRequest(state);
516    }
517
518    state.bufferedRequestCount = 0;
519  } else {
520    // Slow case, write chunks one-by-one
521    while (entry) {
522      var chunk = entry.chunk;
523      var encoding = entry.encoding;
524      var cb = entry.callback;
525      var len = state.objectMode ? 1 : chunk.length;
526      doWrite(stream, state, false, len, chunk, encoding, cb);
527      entry = entry.next;
528      state.bufferedRequestCount--; // if we didn't call the onwrite immediately, then
529      // it means that we need to wait until it does.
530      // also, that means that the chunk and cb are currently
531      // being processed, so move the buffer counter past them.
532
533      if (state.writing) {
534        break;
535      }
536    }
537
538    if (entry === null) state.lastBufferedRequest = null;
539  }
540
541  state.bufferedRequest = entry;
542  state.bufferProcessing = false;
543}
544
545Writable.prototype._write = function (chunk, encoding, cb) {
546  cb(new ERR_METHOD_NOT_IMPLEMENTED('_write()'));
547};
548
549Writable.prototype._writev = null;
550
551Writable.prototype.end = function (chunk, encoding, cb) {
552  var state = this._writableState;
553
554  if (typeof chunk === 'function') {
555    cb = chunk;
556    chunk = null;
557    encoding = null;
558  } else if (typeof encoding === 'function') {
559    cb = encoding;
560    encoding = null;
561  }
562
563  if (chunk !== null && chunk !== undefined) this.write(chunk, encoding); // .end() fully uncorks
564
565  if (state.corked) {
566    state.corked = 1;
567    this.uncork();
568  } // ignore unnecessary end() calls.
569
570
571  if (!state.ending) endWritable(this, state, cb);
572  return this;
573};
574
575Object.defineProperty(Writable.prototype, 'writableLength', {
576  // making it explicit this property is not enumerable
577  // because otherwise some prototype manipulation in
578  // userland will fail
579  enumerable: false,
580  get: function get() {
581    return this._writableState.length;
582  }
583});
584
585function needFinish(state) {
586  return state.ending && state.length === 0 && state.bufferedRequest === null && !state.finished && !state.writing;
587}
588
589function callFinal(stream, state) {
590  stream._final(function (err) {
591    state.pendingcb--;
592
593    if (err) {
594      errorOrDestroy(stream, err);
595    }
596
597    state.prefinished = true;
598    stream.emit('prefinish');
599    finishMaybe(stream, state);
600  });
601}
602
603function prefinish(stream, state) {
604  if (!state.prefinished && !state.finalCalled) {
605    if (typeof stream._final === 'function' && !state.destroyed) {
606      state.pendingcb++;
607      state.finalCalled = true;
608      process.nextTick(callFinal, stream, state);
609    } else {
610      state.prefinished = true;
611      stream.emit('prefinish');
612    }
613  }
614}
615
616function finishMaybe(stream, state) {
617  var need = needFinish(state);
618
619  if (need) {
620    prefinish(stream, state);
621
622    if (state.pendingcb === 0) {
623      state.finished = true;
624      stream.emit('finish');
625
626      if (state.autoDestroy) {
627        // In case of duplex streams we need a way to detect
628        // if the readable side is ready for autoDestroy as well
629        var rState = stream._readableState;
630
631        if (!rState || rState.autoDestroy && rState.endEmitted) {
632          stream.destroy();
633        }
634      }
635    }
636  }
637
638  return need;
639}
640
641function endWritable(stream, state, cb) {
642  state.ending = true;
643  finishMaybe(stream, state);
644
645  if (cb) {
646    if (state.finished) process.nextTick(cb);else stream.once('finish', cb);
647  }
648
649  state.ended = true;
650  stream.writable = false;
651}
652
653function onCorkedFinish(corkReq, state, err) {
654  var entry = corkReq.entry;
655  corkReq.entry = null;
656
657  while (entry) {
658    var cb = entry.callback;
659    state.pendingcb--;
660    cb(err);
661    entry = entry.next;
662  } // reuse the free corkReq.
663
664
665  state.corkedRequestsFree.next = corkReq;
666}
667
668Object.defineProperty(Writable.prototype, 'destroyed', {
669  // making it explicit this property is not enumerable
670  // because otherwise some prototype manipulation in
671  // userland will fail
672  enumerable: false,
673  get: function get() {
674    if (this._writableState === undefined) {
675      return false;
676    }
677
678    return this._writableState.destroyed;
679  },
680  set: function set(value) {
681    // we ignore the value if the stream
682    // has not been initialized yet
683    if (!this._writableState) {
684      return;
685    } // backward compatibility, the user is explicitly
686    // managing destroyed
687
688
689    this._writableState.destroyed = value;
690  }
691});
692Writable.prototype.destroy = destroyImpl.destroy;
693Writable.prototype._undestroy = destroyImpl.undestroy;
694
695Writable.prototype._destroy = function (err, cb) {
696  cb(err);
697};