source: trip-planner-front/node_modules/readable-stream/lib/_stream_readable.js

Last change on this file was 6a3a178, checked in by Ema <ema_spirova@…>, 3 years ago

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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'use strict';
22
23module.exports = Readable;
24/*<replacement>*/
25
26var Duplex;
27/*</replacement>*/
28
29Readable.ReadableState = ReadableState;
30/*<replacement>*/
31
32var EE = require('events').EventEmitter;
33
34var EElistenerCount = function EElistenerCount(emitter, type) {
35 return emitter.listeners(type).length;
36};
37/*</replacement>*/
38
39/*<replacement>*/
40
41
42var Stream = require('./internal/streams/stream');
43/*</replacement>*/
44
45
46var Buffer = require('buffer').Buffer;
47
48var OurUint8Array = global.Uint8Array || function () {};
49
50function _uint8ArrayToBuffer(chunk) {
51 return Buffer.from(chunk);
52}
53
54function _isUint8Array(obj) {
55 return Buffer.isBuffer(obj) || obj instanceof OurUint8Array;
56}
57/*<replacement>*/
58
59
60var debugUtil = require('util');
61
62var debug;
63
64if (debugUtil && debugUtil.debuglog) {
65 debug = debugUtil.debuglog('stream');
66} else {
67 debug = function debug() {};
68}
69/*</replacement>*/
70
71
72var BufferList = require('./internal/streams/buffer_list');
73
74var destroyImpl = require('./internal/streams/destroy');
75
76var _require = require('./internal/streams/state'),
77 getHighWaterMark = _require.getHighWaterMark;
78
79var _require$codes = require('../errors').codes,
80 ERR_INVALID_ARG_TYPE = _require$codes.ERR_INVALID_ARG_TYPE,
81 ERR_STREAM_PUSH_AFTER_EOF = _require$codes.ERR_STREAM_PUSH_AFTER_EOF,
82 ERR_METHOD_NOT_IMPLEMENTED = _require$codes.ERR_METHOD_NOT_IMPLEMENTED,
83 ERR_STREAM_UNSHIFT_AFTER_END_EVENT = _require$codes.ERR_STREAM_UNSHIFT_AFTER_END_EVENT; // Lazy loaded to improve the startup performance.
84
85
86var StringDecoder;
87var createReadableStreamAsyncIterator;
88var from;
89
90require('inherits')(Readable, Stream);
91
92var errorOrDestroy = destroyImpl.errorOrDestroy;
93var kProxyEvents = ['error', 'close', 'destroy', 'pause', 'resume'];
94
95function prependListener(emitter, event, fn) {
96 // Sadly this is not cacheable as some libraries bundle their own
97 // event emitter implementation with them.
98 if (typeof emitter.prependListener === 'function') return emitter.prependListener(event, fn); // This is a hack to make sure that our error handler is attached before any
99 // userland ones. NEVER DO THIS. This is here only because this code needs
100 // to continue to work with older versions of Node.js that do not include
101 // the prependListener() method. The goal is to eventually remove this hack.
102
103 if (!emitter._events || !emitter._events[event]) emitter.on(event, fn);else if (Array.isArray(emitter._events[event])) emitter._events[event].unshift(fn);else emitter._events[event] = [fn, emitter._events[event]];
104}
105
106function ReadableState(options, stream, isDuplex) {
107 Duplex = Duplex || require('./_stream_duplex');
108 options = options || {}; // Duplex streams are both readable and writable, but share
109 // the same options object.
110 // However, some cases require setting options to different
111 // values for the readable and the writable sides of the duplex stream.
112 // These options can be provided separately as readableXXX and writableXXX.
113
114 if (typeof isDuplex !== 'boolean') isDuplex = stream instanceof Duplex; // object stream flag. Used to make read(n) ignore n and to
115 // make all the buffer merging and length checks go away
116
117 this.objectMode = !!options.objectMode;
118 if (isDuplex) this.objectMode = this.objectMode || !!options.readableObjectMode; // the point at which it stops calling _read() to fill the buffer
119 // Note: 0 is a valid value, means "don't call _read preemptively ever"
120
121 this.highWaterMark = getHighWaterMark(this, options, 'readableHighWaterMark', isDuplex); // A linked list is used to store data chunks instead of an array because the
122 // linked list can remove elements from the beginning faster than
123 // array.shift()
124
125 this.buffer = new BufferList();
126 this.length = 0;
127 this.pipes = null;
128 this.pipesCount = 0;
129 this.flowing = null;
130 this.ended = false;
131 this.endEmitted = false;
132 this.reading = false; // a flag to be able to tell if the event 'readable'/'data' is emitted
133 // immediately, or on a later tick. We set this to true at first, because
134 // any actions that shouldn't happen until "later" should generally also
135 // not happen before the first read call.
136
137 this.sync = true; // whenever we return null, then we set a flag to say
138 // that we're awaiting a 'readable' event emission.
139
140 this.needReadable = false;
141 this.emittedReadable = false;
142 this.readableListening = false;
143 this.resumeScheduled = false;
144 this.paused = true; // Should close be emitted on destroy. Defaults to true.
145
146 this.emitClose = options.emitClose !== false; // Should .destroy() be called after 'end' (and potentially 'finish')
147
148 this.autoDestroy = !!options.autoDestroy; // has it been destroyed
149
150 this.destroyed = false; // Crypto is kind of old and crusty. Historically, its default string
151 // encoding is 'binary' so we have to make this configurable.
152 // Everything else in the universe uses 'utf8', though.
153
154 this.defaultEncoding = options.defaultEncoding || 'utf8'; // the number of writers that are awaiting a drain event in .pipe()s
155
156 this.awaitDrain = 0; // if true, a maybeReadMore has been scheduled
157
158 this.readingMore = false;
159 this.decoder = null;
160 this.encoding = null;
161
162 if (options.encoding) {
163 if (!StringDecoder) StringDecoder = require('string_decoder/').StringDecoder;
164 this.decoder = new StringDecoder(options.encoding);
165 this.encoding = options.encoding;
166 }
167}
168
169function Readable(options) {
170 Duplex = Duplex || require('./_stream_duplex');
171 if (!(this instanceof Readable)) return new Readable(options); // Checking for a Stream.Duplex instance is faster here instead of inside
172 // the ReadableState constructor, at least with V8 6.5
173
174 var isDuplex = this instanceof Duplex;
175 this._readableState = new ReadableState(options, this, isDuplex); // legacy
176
177 this.readable = true;
178
179 if (options) {
180 if (typeof options.read === 'function') this._read = options.read;
181 if (typeof options.destroy === 'function') this._destroy = options.destroy;
182 }
183
184 Stream.call(this);
185}
186
187Object.defineProperty(Readable.prototype, 'destroyed', {
188 // making it explicit this property is not enumerable
189 // because otherwise some prototype manipulation in
190 // userland will fail
191 enumerable: false,
192 get: function get() {
193 if (this._readableState === undefined) {
194 return false;
195 }
196
197 return this._readableState.destroyed;
198 },
199 set: function set(value) {
200 // we ignore the value if the stream
201 // has not been initialized yet
202 if (!this._readableState) {
203 return;
204 } // backward compatibility, the user is explicitly
205 // managing destroyed
206
207
208 this._readableState.destroyed = value;
209 }
210});
211Readable.prototype.destroy = destroyImpl.destroy;
212Readable.prototype._undestroy = destroyImpl.undestroy;
213
214Readable.prototype._destroy = function (err, cb) {
215 cb(err);
216}; // Manually shove something into the read() buffer.
217// This returns true if the highWaterMark has not been hit yet,
218// similar to how Writable.write() returns true if you should
219// write() some more.
220
221
222Readable.prototype.push = function (chunk, encoding) {
223 var state = this._readableState;
224 var skipChunkCheck;
225
226 if (!state.objectMode) {
227 if (typeof chunk === 'string') {
228 encoding = encoding || state.defaultEncoding;
229
230 if (encoding !== state.encoding) {
231 chunk = Buffer.from(chunk, encoding);
232 encoding = '';
233 }
234
235 skipChunkCheck = true;
236 }
237 } else {
238 skipChunkCheck = true;
239 }
240
241 return readableAddChunk(this, chunk, encoding, false, skipChunkCheck);
242}; // Unshift should *always* be something directly out of read()
243
244
245Readable.prototype.unshift = function (chunk) {
246 return readableAddChunk(this, chunk, null, true, false);
247};
248
249function readableAddChunk(stream, chunk, encoding, addToFront, skipChunkCheck) {
250 debug('readableAddChunk', chunk);
251 var state = stream._readableState;
252
253 if (chunk === null) {
254 state.reading = false;
255 onEofChunk(stream, state);
256 } else {
257 var er;
258 if (!skipChunkCheck) er = chunkInvalid(state, chunk);
259
260 if (er) {
261 errorOrDestroy(stream, er);
262 } else if (state.objectMode || chunk && chunk.length > 0) {
263 if (typeof chunk !== 'string' && !state.objectMode && Object.getPrototypeOf(chunk) !== Buffer.prototype) {
264 chunk = _uint8ArrayToBuffer(chunk);
265 }
266
267 if (addToFront) {
268 if (state.endEmitted) errorOrDestroy(stream, new ERR_STREAM_UNSHIFT_AFTER_END_EVENT());else addChunk(stream, state, chunk, true);
269 } else if (state.ended) {
270 errorOrDestroy(stream, new ERR_STREAM_PUSH_AFTER_EOF());
271 } else if (state.destroyed) {
272 return false;
273 } else {
274 state.reading = false;
275
276 if (state.decoder && !encoding) {
277 chunk = state.decoder.write(chunk);
278 if (state.objectMode || chunk.length !== 0) addChunk(stream, state, chunk, false);else maybeReadMore(stream, state);
279 } else {
280 addChunk(stream, state, chunk, false);
281 }
282 }
283 } else if (!addToFront) {
284 state.reading = false;
285 maybeReadMore(stream, state);
286 }
287 } // We can push more data if we are below the highWaterMark.
288 // Also, if we have no data yet, we can stand some more bytes.
289 // This is to work around cases where hwm=0, such as the repl.
290
291
292 return !state.ended && (state.length < state.highWaterMark || state.length === 0);
293}
294
295function addChunk(stream, state, chunk, addToFront) {
296 if (state.flowing && state.length === 0 && !state.sync) {
297 state.awaitDrain = 0;
298 stream.emit('data', chunk);
299 } else {
300 // update the buffer info.
301 state.length += state.objectMode ? 1 : chunk.length;
302 if (addToFront) state.buffer.unshift(chunk);else state.buffer.push(chunk);
303 if (state.needReadable) emitReadable(stream);
304 }
305
306 maybeReadMore(stream, state);
307}
308
309function chunkInvalid(state, chunk) {
310 var er;
311
312 if (!_isUint8Array(chunk) && typeof chunk !== 'string' && chunk !== undefined && !state.objectMode) {
313 er = new ERR_INVALID_ARG_TYPE('chunk', ['string', 'Buffer', 'Uint8Array'], chunk);
314 }
315
316 return er;
317}
318
319Readable.prototype.isPaused = function () {
320 return this._readableState.flowing === false;
321}; // backwards compatibility.
322
323
324Readable.prototype.setEncoding = function (enc) {
325 if (!StringDecoder) StringDecoder = require('string_decoder/').StringDecoder;
326 var decoder = new StringDecoder(enc);
327 this._readableState.decoder = decoder; // If setEncoding(null), decoder.encoding equals utf8
328
329 this._readableState.encoding = this._readableState.decoder.encoding; // Iterate over current buffer to convert already stored Buffers:
330
331 var p = this._readableState.buffer.head;
332 var content = '';
333
334 while (p !== null) {
335 content += decoder.write(p.data);
336 p = p.next;
337 }
338
339 this._readableState.buffer.clear();
340
341 if (content !== '') this._readableState.buffer.push(content);
342 this._readableState.length = content.length;
343 return this;
344}; // Don't raise the hwm > 1GB
345
346
347var MAX_HWM = 0x40000000;
348
349function computeNewHighWaterMark(n) {
350 if (n >= MAX_HWM) {
351 // TODO(ronag): Throw ERR_VALUE_OUT_OF_RANGE.
352 n = MAX_HWM;
353 } else {
354 // Get the next highest power of 2 to prevent increasing hwm excessively in
355 // tiny amounts
356 n--;
357 n |= n >>> 1;
358 n |= n >>> 2;
359 n |= n >>> 4;
360 n |= n >>> 8;
361 n |= n >>> 16;
362 n++;
363 }
364
365 return n;
366} // This function is designed to be inlinable, so please take care when making
367// changes to the function body.
368
369
370function howMuchToRead(n, state) {
371 if (n <= 0 || state.length === 0 && state.ended) return 0;
372 if (state.objectMode) return 1;
373
374 if (n !== n) {
375 // Only flow one buffer at a time
376 if (state.flowing && state.length) return state.buffer.head.data.length;else return state.length;
377 } // If we're asking for more than the current hwm, then raise the hwm.
378
379
380 if (n > state.highWaterMark) state.highWaterMark = computeNewHighWaterMark(n);
381 if (n <= state.length) return n; // Don't have enough
382
383 if (!state.ended) {
384 state.needReadable = true;
385 return 0;
386 }
387
388 return state.length;
389} // you can override either this method, or the async _read(n) below.
390
391
392Readable.prototype.read = function (n) {
393 debug('read', n);
394 n = parseInt(n, 10);
395 var state = this._readableState;
396 var nOrig = n;
397 if (n !== 0) state.emittedReadable = false; // if we're doing read(0) to trigger a readable event, but we
398 // already have a bunch of data in the buffer, then just trigger
399 // the 'readable' event and move on.
400
401 if (n === 0 && state.needReadable && ((state.highWaterMark !== 0 ? state.length >= state.highWaterMark : state.length > 0) || state.ended)) {
402 debug('read: emitReadable', state.length, state.ended);
403 if (state.length === 0 && state.ended) endReadable(this);else emitReadable(this);
404 return null;
405 }
406
407 n = howMuchToRead(n, state); // if we've ended, and we're now clear, then finish it up.
408
409 if (n === 0 && state.ended) {
410 if (state.length === 0) endReadable(this);
411 return null;
412 } // All the actual chunk generation logic needs to be
413 // *below* the call to _read. The reason is that in certain
414 // synthetic stream cases, such as passthrough streams, _read
415 // may be a completely synchronous operation which may change
416 // the state of the read buffer, providing enough data when
417 // before there was *not* enough.
418 //
419 // So, the steps are:
420 // 1. Figure out what the state of things will be after we do
421 // a read from the buffer.
422 //
423 // 2. If that resulting state will trigger a _read, then call _read.
424 // Note that this may be asynchronous, or synchronous. Yes, it is
425 // deeply ugly to write APIs this way, but that still doesn't mean
426 // that the Readable class should behave improperly, as streams are
427 // designed to be sync/async agnostic.
428 // Take note if the _read call is sync or async (ie, if the read call
429 // has returned yet), so that we know whether or not it's safe to emit
430 // 'readable' etc.
431 //
432 // 3. Actually pull the requested chunks out of the buffer and return.
433 // if we need a readable event, then we need to do some reading.
434
435
436 var doRead = state.needReadable;
437 debug('need readable', doRead); // if we currently have less than the highWaterMark, then also read some
438
439 if (state.length === 0 || state.length - n < state.highWaterMark) {
440 doRead = true;
441 debug('length less than watermark', doRead);
442 } // however, if we've ended, then there's no point, and if we're already
443 // reading, then it's unnecessary.
444
445
446 if (state.ended || state.reading) {
447 doRead = false;
448 debug('reading or ended', doRead);
449 } else if (doRead) {
450 debug('do read');
451 state.reading = true;
452 state.sync = true; // if the length is currently zero, then we *need* a readable event.
453
454 if (state.length === 0) state.needReadable = true; // call internal read method
455
456 this._read(state.highWaterMark);
457
458 state.sync = false; // If _read pushed data synchronously, then `reading` will be false,
459 // and we need to re-evaluate how much data we can return to the user.
460
461 if (!state.reading) n = howMuchToRead(nOrig, state);
462 }
463
464 var ret;
465 if (n > 0) ret = fromList(n, state);else ret = null;
466
467 if (ret === null) {
468 state.needReadable = state.length <= state.highWaterMark;
469 n = 0;
470 } else {
471 state.length -= n;
472 state.awaitDrain = 0;
473 }
474
475 if (state.length === 0) {
476 // If we have nothing in the buffer, then we want to know
477 // as soon as we *do* get something into the buffer.
478 if (!state.ended) state.needReadable = true; // If we tried to read() past the EOF, then emit end on the next tick.
479
480 if (nOrig !== n && state.ended) endReadable(this);
481 }
482
483 if (ret !== null) this.emit('data', ret);
484 return ret;
485};
486
487function onEofChunk(stream, state) {
488 debug('onEofChunk');
489 if (state.ended) return;
490
491 if (state.decoder) {
492 var chunk = state.decoder.end();
493
494 if (chunk && chunk.length) {
495 state.buffer.push(chunk);
496 state.length += state.objectMode ? 1 : chunk.length;
497 }
498 }
499
500 state.ended = true;
501
502 if (state.sync) {
503 // if we are sync, wait until next tick to emit the data.
504 // Otherwise we risk emitting data in the flow()
505 // the readable code triggers during a read() call
506 emitReadable(stream);
507 } else {
508 // emit 'readable' now to make sure it gets picked up.
509 state.needReadable = false;
510
511 if (!state.emittedReadable) {
512 state.emittedReadable = true;
513 emitReadable_(stream);
514 }
515 }
516} // Don't emit readable right away in sync mode, because this can trigger
517// another read() call => stack overflow. This way, it might trigger
518// a nextTick recursion warning, but that's not so bad.
519
520
521function emitReadable(stream) {
522 var state = stream._readableState;
523 debug('emitReadable', state.needReadable, state.emittedReadable);
524 state.needReadable = false;
525
526 if (!state.emittedReadable) {
527 debug('emitReadable', state.flowing);
528 state.emittedReadable = true;
529 process.nextTick(emitReadable_, stream);
530 }
531}
532
533function emitReadable_(stream) {
534 var state = stream._readableState;
535 debug('emitReadable_', state.destroyed, state.length, state.ended);
536
537 if (!state.destroyed && (state.length || state.ended)) {
538 stream.emit('readable');
539 state.emittedReadable = false;
540 } // The stream needs another readable event if
541 // 1. It is not flowing, as the flow mechanism will take
542 // care of it.
543 // 2. It is not ended.
544 // 3. It is below the highWaterMark, so we can schedule
545 // another readable later.
546
547
548 state.needReadable = !state.flowing && !state.ended && state.length <= state.highWaterMark;
549 flow(stream);
550} // at this point, the user has presumably seen the 'readable' event,
551// and called read() to consume some data. that may have triggered
552// in turn another _read(n) call, in which case reading = true if
553// it's in progress.
554// However, if we're not ended, or reading, and the length < hwm,
555// then go ahead and try to read some more preemptively.
556
557
558function maybeReadMore(stream, state) {
559 if (!state.readingMore) {
560 state.readingMore = true;
561 process.nextTick(maybeReadMore_, stream, state);
562 }
563}
564
565function maybeReadMore_(stream, state) {
566 // Attempt to read more data if we should.
567 //
568 // The conditions for reading more data are (one of):
569 // - Not enough data buffered (state.length < state.highWaterMark). The loop
570 // is responsible for filling the buffer with enough data if such data
571 // is available. If highWaterMark is 0 and we are not in the flowing mode
572 // we should _not_ attempt to buffer any extra data. We'll get more data
573 // when the stream consumer calls read() instead.
574 // - No data in the buffer, and the stream is in flowing mode. In this mode
575 // the loop below is responsible for ensuring read() is called. Failing to
576 // call read here would abort the flow and there's no other mechanism for
577 // continuing the flow if the stream consumer has just subscribed to the
578 // 'data' event.
579 //
580 // In addition to the above conditions to keep reading data, the following
581 // conditions prevent the data from being read:
582 // - The stream has ended (state.ended).
583 // - There is already a pending 'read' operation (state.reading). This is a
584 // case where the the stream has called the implementation defined _read()
585 // method, but they are processing the call asynchronously and have _not_
586 // called push() with new data. In this case we skip performing more
587 // read()s. The execution ends in this method again after the _read() ends
588 // up calling push() with more data.
589 while (!state.reading && !state.ended && (state.length < state.highWaterMark || state.flowing && state.length === 0)) {
590 var len = state.length;
591 debug('maybeReadMore read 0');
592 stream.read(0);
593 if (len === state.length) // didn't get any data, stop spinning.
594 break;
595 }
596
597 state.readingMore = false;
598} // abstract method. to be overridden in specific implementation classes.
599// call cb(er, data) where data is <= n in length.
600// for virtual (non-string, non-buffer) streams, "length" is somewhat
601// arbitrary, and perhaps not very meaningful.
602
603
604Readable.prototype._read = function (n) {
605 errorOrDestroy(this, new ERR_METHOD_NOT_IMPLEMENTED('_read()'));
606};
607
608Readable.prototype.pipe = function (dest, pipeOpts) {
609 var src = this;
610 var state = this._readableState;
611
612 switch (state.pipesCount) {
613 case 0:
614 state.pipes = dest;
615 break;
616
617 case 1:
618 state.pipes = [state.pipes, dest];
619 break;
620
621 default:
622 state.pipes.push(dest);
623 break;
624 }
625
626 state.pipesCount += 1;
627 debug('pipe count=%d opts=%j', state.pipesCount, pipeOpts);
628 var doEnd = (!pipeOpts || pipeOpts.end !== false) && dest !== process.stdout && dest !== process.stderr;
629 var endFn = doEnd ? onend : unpipe;
630 if (state.endEmitted) process.nextTick(endFn);else src.once('end', endFn);
631 dest.on('unpipe', onunpipe);
632
633 function onunpipe(readable, unpipeInfo) {
634 debug('onunpipe');
635
636 if (readable === src) {
637 if (unpipeInfo && unpipeInfo.hasUnpiped === false) {
638 unpipeInfo.hasUnpiped = true;
639 cleanup();
640 }
641 }
642 }
643
644 function onend() {
645 debug('onend');
646 dest.end();
647 } // when the dest drains, it reduces the awaitDrain counter
648 // on the source. This would be more elegant with a .once()
649 // handler in flow(), but adding and removing repeatedly is
650 // too slow.
651
652
653 var ondrain = pipeOnDrain(src);
654 dest.on('drain', ondrain);
655 var cleanedUp = false;
656
657 function cleanup() {
658 debug('cleanup'); // cleanup event handlers once the pipe is broken
659
660 dest.removeListener('close', onclose);
661 dest.removeListener('finish', onfinish);
662 dest.removeListener('drain', ondrain);
663 dest.removeListener('error', onerror);
664 dest.removeListener('unpipe', onunpipe);
665 src.removeListener('end', onend);
666 src.removeListener('end', unpipe);
667 src.removeListener('data', ondata);
668 cleanedUp = true; // if the reader is waiting for a drain event from this
669 // specific writer, then it would cause it to never start
670 // flowing again.
671 // So, if this is awaiting a drain, then we just call it now.
672 // If we don't know, then assume that we are waiting for one.
673
674 if (state.awaitDrain && (!dest._writableState || dest._writableState.needDrain)) ondrain();
675 }
676
677 src.on('data', ondata);
678
679 function ondata(chunk) {
680 debug('ondata');
681 var ret = dest.write(chunk);
682 debug('dest.write', ret);
683
684 if (ret === false) {
685 // If the user unpiped during `dest.write()`, it is possible
686 // to get stuck in a permanently paused state if that write
687 // also returned false.
688 // => Check whether `dest` is still a piping destination.
689 if ((state.pipesCount === 1 && state.pipes === dest || state.pipesCount > 1 && indexOf(state.pipes, dest) !== -1) && !cleanedUp) {
690 debug('false write response, pause', state.awaitDrain);
691 state.awaitDrain++;
692 }
693
694 src.pause();
695 }
696 } // if the dest has an error, then stop piping into it.
697 // however, don't suppress the throwing behavior for this.
698
699
700 function onerror(er) {
701 debug('onerror', er);
702 unpipe();
703 dest.removeListener('error', onerror);
704 if (EElistenerCount(dest, 'error') === 0) errorOrDestroy(dest, er);
705 } // Make sure our error handler is attached before userland ones.
706
707
708 prependListener(dest, 'error', onerror); // Both close and finish should trigger unpipe, but only once.
709
710 function onclose() {
711 dest.removeListener('finish', onfinish);
712 unpipe();
713 }
714
715 dest.once('close', onclose);
716
717 function onfinish() {
718 debug('onfinish');
719 dest.removeListener('close', onclose);
720 unpipe();
721 }
722
723 dest.once('finish', onfinish);
724
725 function unpipe() {
726 debug('unpipe');
727 src.unpipe(dest);
728 } // tell the dest that it's being piped to
729
730
731 dest.emit('pipe', src); // start the flow if it hasn't been started already.
732
733 if (!state.flowing) {
734 debug('pipe resume');
735 src.resume();
736 }
737
738 return dest;
739};
740
741function pipeOnDrain(src) {
742 return function pipeOnDrainFunctionResult() {
743 var state = src._readableState;
744 debug('pipeOnDrain', state.awaitDrain);
745 if (state.awaitDrain) state.awaitDrain--;
746
747 if (state.awaitDrain === 0 && EElistenerCount(src, 'data')) {
748 state.flowing = true;
749 flow(src);
750 }
751 };
752}
753
754Readable.prototype.unpipe = function (dest) {
755 var state = this._readableState;
756 var unpipeInfo = {
757 hasUnpiped: false
758 }; // if we're not piping anywhere, then do nothing.
759
760 if (state.pipesCount === 0) return this; // just one destination. most common case.
761
762 if (state.pipesCount === 1) {
763 // passed in one, but it's not the right one.
764 if (dest && dest !== state.pipes) return this;
765 if (!dest) dest = state.pipes; // got a match.
766
767 state.pipes = null;
768 state.pipesCount = 0;
769 state.flowing = false;
770 if (dest) dest.emit('unpipe', this, unpipeInfo);
771 return this;
772 } // slow case. multiple pipe destinations.
773
774
775 if (!dest) {
776 // remove all.
777 var dests = state.pipes;
778 var len = state.pipesCount;
779 state.pipes = null;
780 state.pipesCount = 0;
781 state.flowing = false;
782
783 for (var i = 0; i < len; i++) {
784 dests[i].emit('unpipe', this, {
785 hasUnpiped: false
786 });
787 }
788
789 return this;
790 } // try to find the right one.
791
792
793 var index = indexOf(state.pipes, dest);
794 if (index === -1) return this;
795 state.pipes.splice(index, 1);
796 state.pipesCount -= 1;
797 if (state.pipesCount === 1) state.pipes = state.pipes[0];
798 dest.emit('unpipe', this, unpipeInfo);
799 return this;
800}; // set up data events if they are asked for
801// Ensure readable listeners eventually get something
802
803
804Readable.prototype.on = function (ev, fn) {
805 var res = Stream.prototype.on.call(this, ev, fn);
806 var state = this._readableState;
807
808 if (ev === 'data') {
809 // update readableListening so that resume() may be a no-op
810 // a few lines down. This is needed to support once('readable').
811 state.readableListening = this.listenerCount('readable') > 0; // Try start flowing on next tick if stream isn't explicitly paused
812
813 if (state.flowing !== false) this.resume();
814 } else if (ev === 'readable') {
815 if (!state.endEmitted && !state.readableListening) {
816 state.readableListening = state.needReadable = true;
817 state.flowing = false;
818 state.emittedReadable = false;
819 debug('on readable', state.length, state.reading);
820
821 if (state.length) {
822 emitReadable(this);
823 } else if (!state.reading) {
824 process.nextTick(nReadingNextTick, this);
825 }
826 }
827 }
828
829 return res;
830};
831
832Readable.prototype.addListener = Readable.prototype.on;
833
834Readable.prototype.removeListener = function (ev, fn) {
835 var res = Stream.prototype.removeListener.call(this, ev, fn);
836
837 if (ev === 'readable') {
838 // We need to check if there is someone still listening to
839 // readable and reset the state. However this needs to happen
840 // after readable has been emitted but before I/O (nextTick) to
841 // support once('readable', fn) cycles. This means that calling
842 // resume within the same tick will have no
843 // effect.
844 process.nextTick(updateReadableListening, this);
845 }
846
847 return res;
848};
849
850Readable.prototype.removeAllListeners = function (ev) {
851 var res = Stream.prototype.removeAllListeners.apply(this, arguments);
852
853 if (ev === 'readable' || ev === undefined) {
854 // We need to check if there is someone still listening to
855 // readable and reset the state. However this needs to happen
856 // after readable has been emitted but before I/O (nextTick) to
857 // support once('readable', fn) cycles. This means that calling
858 // resume within the same tick will have no
859 // effect.
860 process.nextTick(updateReadableListening, this);
861 }
862
863 return res;
864};
865
866function updateReadableListening(self) {
867 var state = self._readableState;
868 state.readableListening = self.listenerCount('readable') > 0;
869
870 if (state.resumeScheduled && !state.paused) {
871 // flowing needs to be set to true now, otherwise
872 // the upcoming resume will not flow.
873 state.flowing = true; // crude way to check if we should resume
874 } else if (self.listenerCount('data') > 0) {
875 self.resume();
876 }
877}
878
879function nReadingNextTick(self) {
880 debug('readable nexttick read 0');
881 self.read(0);
882} // pause() and resume() are remnants of the legacy readable stream API
883// If the user uses them, then switch into old mode.
884
885
886Readable.prototype.resume = function () {
887 var state = this._readableState;
888
889 if (!state.flowing) {
890 debug('resume'); // we flow only if there is no one listening
891 // for readable, but we still have to call
892 // resume()
893
894 state.flowing = !state.readableListening;
895 resume(this, state);
896 }
897
898 state.paused = false;
899 return this;
900};
901
902function resume(stream, state) {
903 if (!state.resumeScheduled) {
904 state.resumeScheduled = true;
905 process.nextTick(resume_, stream, state);
906 }
907}
908
909function resume_(stream, state) {
910 debug('resume', state.reading);
911
912 if (!state.reading) {
913 stream.read(0);
914 }
915
916 state.resumeScheduled = false;
917 stream.emit('resume');
918 flow(stream);
919 if (state.flowing && !state.reading) stream.read(0);
920}
921
922Readable.prototype.pause = function () {
923 debug('call pause flowing=%j', this._readableState.flowing);
924
925 if (this._readableState.flowing !== false) {
926 debug('pause');
927 this._readableState.flowing = false;
928 this.emit('pause');
929 }
930
931 this._readableState.paused = true;
932 return this;
933};
934
935function flow(stream) {
936 var state = stream._readableState;
937 debug('flow', state.flowing);
938
939 while (state.flowing && stream.read() !== null) {
940 ;
941 }
942} // wrap an old-style stream as the async data source.
943// This is *not* part of the readable stream interface.
944// It is an ugly unfortunate mess of history.
945
946
947Readable.prototype.wrap = function (stream) {
948 var _this = this;
949
950 var state = this._readableState;
951 var paused = false;
952 stream.on('end', function () {
953 debug('wrapped end');
954
955 if (state.decoder && !state.ended) {
956 var chunk = state.decoder.end();
957 if (chunk && chunk.length) _this.push(chunk);
958 }
959
960 _this.push(null);
961 });
962 stream.on('data', function (chunk) {
963 debug('wrapped data');
964 if (state.decoder) chunk = state.decoder.write(chunk); // don't skip over falsy values in objectMode
965
966 if (state.objectMode && (chunk === null || chunk === undefined)) return;else if (!state.objectMode && (!chunk || !chunk.length)) return;
967
968 var ret = _this.push(chunk);
969
970 if (!ret) {
971 paused = true;
972 stream.pause();
973 }
974 }); // proxy all the other methods.
975 // important when wrapping filters and duplexes.
976
977 for (var i in stream) {
978 if (this[i] === undefined && typeof stream[i] === 'function') {
979 this[i] = function methodWrap(method) {
980 return function methodWrapReturnFunction() {
981 return stream[method].apply(stream, arguments);
982 };
983 }(i);
984 }
985 } // proxy certain important events.
986
987
988 for (var n = 0; n < kProxyEvents.length; n++) {
989 stream.on(kProxyEvents[n], this.emit.bind(this, kProxyEvents[n]));
990 } // when we try to consume some more bytes, simply unpause the
991 // underlying stream.
992
993
994 this._read = function (n) {
995 debug('wrapped _read', n);
996
997 if (paused) {
998 paused = false;
999 stream.resume();
1000 }
1001 };
1002
1003 return this;
1004};
1005
1006if (typeof Symbol === 'function') {
1007 Readable.prototype[Symbol.asyncIterator] = function () {
1008 if (createReadableStreamAsyncIterator === undefined) {
1009 createReadableStreamAsyncIterator = require('./internal/streams/async_iterator');
1010 }
1011
1012 return createReadableStreamAsyncIterator(this);
1013 };
1014}
1015
1016Object.defineProperty(Readable.prototype, 'readableHighWaterMark', {
1017 // making it explicit this property is not enumerable
1018 // because otherwise some prototype manipulation in
1019 // userland will fail
1020 enumerable: false,
1021 get: function get() {
1022 return this._readableState.highWaterMark;
1023 }
1024});
1025Object.defineProperty(Readable.prototype, 'readableBuffer', {
1026 // making it explicit this property is not enumerable
1027 // because otherwise some prototype manipulation in
1028 // userland will fail
1029 enumerable: false,
1030 get: function get() {
1031 return this._readableState && this._readableState.buffer;
1032 }
1033});
1034Object.defineProperty(Readable.prototype, 'readableFlowing', {
1035 // making it explicit this property is not enumerable
1036 // because otherwise some prototype manipulation in
1037 // userland will fail
1038 enumerable: false,
1039 get: function get() {
1040 return this._readableState.flowing;
1041 },
1042 set: function set(state) {
1043 if (this._readableState) {
1044 this._readableState.flowing = state;
1045 }
1046 }
1047}); // exposed for testing purposes only.
1048
1049Readable._fromList = fromList;
1050Object.defineProperty(Readable.prototype, 'readableLength', {
1051 // making it explicit this property is not enumerable
1052 // because otherwise some prototype manipulation in
1053 // userland will fail
1054 enumerable: false,
1055 get: function get() {
1056 return this._readableState.length;
1057 }
1058}); // Pluck off n bytes from an array of buffers.
1059// Length is the combined lengths of all the buffers in the list.
1060// This function is designed to be inlinable, so please take care when making
1061// changes to the function body.
1062
1063function fromList(n, state) {
1064 // nothing buffered
1065 if (state.length === 0) return null;
1066 var ret;
1067 if (state.objectMode) ret = state.buffer.shift();else if (!n || n >= state.length) {
1068 // read it all, truncate the list
1069 if (state.decoder) ret = state.buffer.join('');else if (state.buffer.length === 1) ret = state.buffer.first();else ret = state.buffer.concat(state.length);
1070 state.buffer.clear();
1071 } else {
1072 // read part of list
1073 ret = state.buffer.consume(n, state.decoder);
1074 }
1075 return ret;
1076}
1077
1078function endReadable(stream) {
1079 var state = stream._readableState;
1080 debug('endReadable', state.endEmitted);
1081
1082 if (!state.endEmitted) {
1083 state.ended = true;
1084 process.nextTick(endReadableNT, state, stream);
1085 }
1086}
1087
1088function endReadableNT(state, stream) {
1089 debug('endReadableNT', state.endEmitted, state.length); // Check that we didn't get one last unshift.
1090
1091 if (!state.endEmitted && state.length === 0) {
1092 state.endEmitted = true;
1093 stream.readable = false;
1094 stream.emit('end');
1095
1096 if (state.autoDestroy) {
1097 // In case of duplex streams we need a way to detect
1098 // if the writable side is ready for autoDestroy as well
1099 var wState = stream._writableState;
1100
1101 if (!wState || wState.autoDestroy && wState.finished) {
1102 stream.destroy();
1103 }
1104 }
1105 }
1106}
1107
1108if (typeof Symbol === 'function') {
1109 Readable.from = function (iterable, opts) {
1110 if (from === undefined) {
1111 from = require('./internal/streams/from');
1112 }
1113
1114 return from(Readable, iterable, opts);
1115 };
1116}
1117
1118function indexOf(xs, x) {
1119 for (var i = 0, l = xs.length; i < l; i++) {
1120 if (xs[i] === x) return i;
1121 }
1122
1123 return -1;
1124}
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