node/lib/_stream_readable.js at master · anchnk/node · GitHub

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// Copyright Joyent, Inc. and other Node contributors.

// Permission is hereby granted, free of charge, to any person obtaining a

// copy of this software and associated documentation files (the

// "Software"), to deal in the Software without restriction, including

// without limitation the rights to use, copy, modify, merge, publish,

// distribute, sublicense, and/or sell copies of the Software, and to permit

// persons to whom the Software is furnished to do so, subject to the

// following conditions:

// The above copyright notice and this permission notice shall be included

// in all copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS

// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN

// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,

// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR

// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE

// USE OR OTHER DEALINGS IN THE SOFTWARE.

'use strict';

module.exports = Readable;

Readable.ReadableState = ReadableState;

const EE = require('events');

const Stream = require('stream');

const Buffer = require('buffer').Buffer;

const util = require('util');

const debug = util.debuglog('stream');

const BufferList = require('internal/streams/BufferList');

var StringDecoder;

util.inherits(Readable, Stream);

const kProxyEvents = ['error', 'close', 'destroy', 'pause', 'resume'];

function prependListener(emitter, event, fn) {

// Sadly this is not cacheable as some libraries bundle their own

// event emitter implementation with them.

if (typeof emitter.prependListener === 'function') {

return emitter.prependListener(event, fn);

} else {

// This is a hack to make sure that our error handler is attached before any

// userland ones. NEVER DO THIS. This is here only because this code needs

// to continue to work with older versions of Node.js that do not include

// the prependListener() method. The goal is to eventually remove this hack.

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]];

}

function ReadableState(options, stream) {

options = options || {};

// object stream flag. Used to make read(n) ignore n and to

// make all the buffer merging and length checks go away

this.objectMode = !!options.objectMode;

if (stream instanceof Stream.Duplex)

this.objectMode = this.objectMode || !!options.readableObjectMode;

// the point at which it stops calling _read() to fill the buffer

// Note: 0 is a valid value, means "don't call _read preemptively ever"

var hwm = options.highWaterMark;

var defaultHwm = this.objectMode ? 16 : 16 * 1024;

this.highWaterMark = (hwm || hwm === 0) ? hwm : defaultHwm;

// cast to ints.

this.highWaterMark = Math.floor(this.highWaterMark);

// A linked list is used to store data chunks instead of an array because the

// linked list can remove elements from the beginning faster than

// array.shift()

this.buffer = new BufferList();

this.length = 0;

this.pipes = null;

this.pipesCount = 0;

this.flowing = null;

this.ended = false;

this.endEmitted = false;

this.reading = false;

// a flag to be able to tell if the event 'readable'/'data' is emitted

// 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 read call.

this.sync = true;

// whenever we return null, then we set a flag to say

// that we're awaiting a 'readable' event emission.

this.needReadable = false;

this.emittedReadable = false;

this.readableListening = false;

this.resumeScheduled = false;

// 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.defaultEncoding || 'utf8';

// the number of writers that are awaiting a drain event in .pipe()s

this.awaitDrain = 0;

// if true, a maybeReadMore has been scheduled

this.readingMore = false;

this.decoder = null;

this.encoding = null;

if (options.encoding) {

if (!StringDecoder)

StringDecoder = require('string_decoder').StringDecoder;

this.decoder = new StringDecoder(options.encoding);

this.encoding = options.encoding;

}

function Readable(options) {

if (!(this instanceof Readable))

return new Readable(options);

this._readableState = new ReadableState(options, this);

// legacy

this.readable = true;

if (options && typeof options.read === 'function')

this._read = options.read;

Stream.call(this);

}

// Manually shove something into the read() buffer.

// This returns true if the highWaterMark has not been hit yet,

// similar to how Writable.write() returns true if you should

// write() some more.

Readable.prototype.push = function(chunk, encoding) {

var state = this._readableState;

if (!state.objectMode && typeof chunk === 'string') {

encoding = encoding || state.defaultEncoding;

if (encoding !== state.encoding) {

chunk = Buffer.from(chunk, encoding);

encoding = '';

}

return readableAddChunk(this, state, chunk, encoding, false);

};

// Unshift should *always* be something directly out of read()

Readable.prototype.unshift = function(chunk) {

var state = this._readableState;

return readableAddChunk(this, state, chunk, '', true);

};

Readable.prototype.isPaused = function() {

return this._readableState.flowing === false;

};

function readableAddChunk(stream, state, chunk, encoding, addToFront) {

var er = chunkInvalid(state, chunk);

if (er) {

stream.emit('error', er);

} else if (chunk === null) {

state.reading = false;

onEofChunk(stream, state);

} else if (state.objectMode || chunk && chunk.length > 0) {

if (state.ended && !addToFront) {

const e = new Error('stream.push() after EOF');

stream.emit('error', e);

} else if (state.endEmitted && addToFront) {

const e = new Error('stream.unshift() after end event');

stream.emit('error', e);

} else {

var skipAdd;

if (state.decoder && !addToFront && !encoding) {

chunk = state.decoder.write(chunk);

skipAdd = (!state.objectMode && chunk.length === 0);

}

if (!addToFront)

state.reading = false;

// Don't add to the buffer if we've decoded to an empty string chunk and

// we're not in object mode

if (!skipAdd) {

// if we want the data now, just emit it.

if (state.flowing && state.length === 0 && !state.sync) {

stream.emit('data', chunk);

stream.read(0);

} else {

// update the buffer info.

state.length += state.objectMode ? 1 : chunk.length;

if (addToFront)

state.buffer.unshift(chunk);

else

state.buffer.push(chunk);

if (state.needReadable)

emitReadable(stream);

}

maybeReadMore(stream, state);

}

} else if (!addToFront) {

state.reading = false;

}

return needMoreData(state);

}

// if it's past the high water mark, we can push in some more.

// Also, if we have no data yet, we can stand some

// more bytes. This is to work around cases where hwm=0,

// such as the repl. Also, if the push() triggered a

// readable event, and the user called read(largeNumber) such that

// needReadable was set, then we ought to push more, so that another

// 'readable' event will be triggered.

function needMoreData(state) {

return !state.ended &&

(state.needReadable ||

state.length < state.highWaterMark ||

state.length === 0);

}

// backwards compatibility.

Readable.prototype.setEncoding = function(enc) {

if (!StringDecoder)

StringDecoder = require('string_decoder').StringDecoder;

this._readableState.decoder = new StringDecoder(enc);

this._readableState.encoding = enc;

return this;

};

// Don't raise the hwm > 8MB

const MAX_HWM = 0x800000;

function computeNewHighWaterMark(n) {

if (n >= MAX_HWM) {

n = MAX_HWM;

} else {

// Get the next highest power of 2 to prevent increasing hwm excessively in

// tiny amounts

n--;

n |= n >>> 1;

n |= n >>> 2;

n |= n >>> 4;

n |= n >>> 8;

n |= n >>> 16;

n++;

}

return n;

}

// This function is designed to be inlinable, so please take care when making

// changes to the function body.

function howMuchToRead(n, state) {

if (n <= 0 || (state.length === 0 && state.ended))

return 0;

if (state.objectMode)

return 1;

if (n !== n) {

// Only flow one buffer at a time

if (state.flowing && state.length)

return state.buffer.head.data.length;

else

return state.length;

}

// If we're asking for more than the current hwm, then raise the hwm.

if (n > state.highWaterMark)

state.highWaterMark = computeNewHighWaterMark(n);

if (n <= state.length)

return n;

// Don't have enough

if (!state.ended) {

state.needReadable = true;

return 0;

}

return state.length;

}

// you can override either this method, or the async _read(n) below.

Readable.prototype.read = function(n) {

debug('read', n);

n = parseInt(n, 10);

var state = this._readableState;

var nOrig = n;

if (n !== 0)

state.emittedReadable = false;

// if we're doing read(0) to trigger a readable event, but we

// already have a bunch of data in the buffer, then just trigger

// the 'readable' event and move on.

if (n === 0 &&

state.needReadable &&

(state.length >= state.highWaterMark || state.ended)) {

debug('read: emitReadable', state.length, state.ended);

if (state.length === 0 && state.ended)

endReadable(this);

else

emitReadable(this);

return null;

}

n = howMuchToRead(n, state);

// if we've ended, and we're now clear, then finish it up.

if (n === 0 && state.ended) {

if (state.length === 0)

endReadable(this);

return null;

}

// All the actual chunk generation logic needs to be

// *below* the call to _read. The reason is that in certain

// synthetic stream cases, such as passthrough streams, _read

// may be a completely synchronous operation which may change

// the state of the read buffer, providing enough data when

// before there was *not* enough.

// So, the steps are:

// 1. Figure out what the state of things will be after we do

// a read from the buffer.

// 2. If that resulting state will trigger a _read, then call _read.

// Note that this may be asynchronous, or synchronous. Yes, it is

// deeply ugly to write APIs this way, but that still doesn't mean

// that the Readable class should behave improperly, as streams are

// designed to be sync/async agnostic.

// Take note if the _read call is sync or async (ie, if the read call

// has returned yet), so that we know whether or not it's safe to emit

// 'readable' etc.

// 3. Actually pull the requested chunks out of the buffer and return.

// if we need a readable event, then we need to do some reading.

var doRead = state.needReadable;

debug('need readable', doRead);

// if we currently have less than the highWaterMark, then also read some

if (state.length === 0 || state.length - n < state.highWaterMark) {

doRead = true;

debug('length less than watermark', doRead);

}

// however, if we've ended, then there's no point, and if we're already

// reading, then it's unnecessary.

if (state.ended || state.reading) {

doRead = false;

debug('reading or ended', doRead);

} else if (doRead) {

debug('do read');

state.reading = true;

state.sync = true;

// if the length is currently zero, then we *need* a readable event.

if (state.length === 0)

state.needReadable = true;

// call internal read method

this._read(state.highWaterMark);

state.sync = false;

// If _read pushed data synchronously, then `reading` will be false,

// and we need to re-evaluate how much data we can return to the user.

if (!state.reading)

n = howMuchToRead(nOrig, state);

}

var ret;

if (n > 0)

ret = fromList(n, state);

else

ret = null;

if (ret === null) {

state.needReadable = true;

n = 0;

} else {

state.length -= n;

}

if (state.length === 0) {

// If we have nothing in the buffer, then we want to know

// as soon as we *do* get something into the buffer.

if (!state.ended)

state.needReadable = true;

// If we tried to read() past the EOF, then emit end on the next tick.

if (nOrig !== n && state.ended)

endReadable(this);

}

if (ret !== null)

this.emit('data', ret);

return ret;

};

function chunkInvalid(state, chunk) {

var er = null;

if (!(chunk instanceof Buffer) &&

typeof chunk !== 'string' &&

chunk !== null &&

chunk !== undefined &&

!state.objectMode) {

er = new TypeError('Invalid non-string/buffer chunk');

}

return er;

}

function onEofChunk(stream, state) {

if (state.ended) return;

if (state.decoder) {

var chunk = state.decoder.end();

if (chunk && chunk.length) {

state.buffer.push(chunk);

state.length += state.objectMode ? 1 : chunk.length;

}

state.ended = true;

// emit 'readable' now to make sure it gets picked up.

emitReadable(stream);

}

// Don't emit readable right away in sync mode, because this can trigger

// another read() call => stack overflow. This way, it might trigger

// a nextTick recursion warning, but that's not so bad.

function emitReadable(stream) {

var state = stream._readableState;

state.needReadable = false;

if (!state.emittedReadable) {

debug('emitReadable', state.flowing);

state.emittedReadable = true;

if (state.sync)

process.nextTick(emitReadable_, stream);

else

emitReadable_(stream);

}

function emitReadable_(stream) {

debug('emit readable');

stream.emit('readable');

flow(stream);

}

// at this point, the user has presumably seen the 'readable' event,

// and called read() to consume some data. that may have triggered

// in turn another _read(n) call, in which case reading = true if

// it's in progress.

// However, if we're not ended, or reading, and the length < hwm,

// then go ahead and try to read some more preemptively.

function maybeReadMore(stream, state) {

if (!state.readingMore) {

state.readingMore = true;

process.nextTick(maybeReadMore_, stream, state);

}

function maybeReadMore_(stream, state) {

var len = state.length;

while (!state.reading && !state.flowing && !state.ended &&

state.length < state.highWaterMark) {

debug('maybeReadMore read 0');

stream.read(0);

if (len === state.length)

// didn't get any data, stop spinning.

break;

else

len = state.length;

}

state.readingMore = false;

}

// abstract method. to be overridden in specific implementation classes.

// call cb(er, data) where data is <= n in length.

// for virtual (non-string, non-buffer) streams, "length" is somewhat

// arbitrary, and perhaps not very meaningful.

Readable.prototype._read = function(n) {

this.emit('error', new Error('_read() is not implemented'));

};

Readable.prototype.pipe = function(dest, pipeOpts) {

var src = this;

var state = this._readableState;

switch (state.pipesCount) {

case 0:

state.pipes = dest;

break;

case 1:

state.pipes = [state.pipes, dest];

break;

default:

state.pipes.push(dest);

break;

}

state.pipesCount += 1;

debug('pipe count=%d opts=%j', state.pipesCount, pipeOpts);

var doEnd = (!pipeOpts || pipeOpts.end !== false) &&

dest !== process.stdout &&

dest !== process.stderr;

var endFn = doEnd ? onend : unpipe;

if (state.endEmitted)

process.nextTick(endFn);

else

src.once('end', endFn);

dest.on('unpipe', onunpipe);

function onunpipe(readable, unpipeInfo) {

debug('onunpipe');

if (readable === src) {

if (unpipeInfo && unpipeInfo.hasUnpiped === false) {

unpipeInfo.hasUnpiped = true;

cleanup();

}

function onend() {

debug('onend');

dest.end();

}

// when the dest drains, it reduces the awaitDrain counter

// on the source. This would be more elegant with a .once()

// handler in flow(), but adding and removing repeatedly is

// too slow.

var ondrain = pipeOnDrain(src);

dest.on('drain', ondrain);

var cleanedUp = false;

function cleanup() {

debug('cleanup');

// cleanup event handlers once the pipe is broken

dest.removeListener('close', onclose);

dest.removeListener('finish', onfinish);

dest.removeListener('drain', ondrain);

dest.removeListener('error', onerror);

dest.removeListener('unpipe', onunpipe);

src.removeListener('end', onend);

src.removeListener('end', unpipe);

src.removeListener('data', ondata);

cleanedUp = true;

// if the reader is waiting for a drain event from this

// specific writer, then it would cause it to never start

// flowing again.

// So, if this is awaiting a drain, then we just call it now.

// If we don't know, then assume that we are waiting for one.

if (state.awaitDrain &&

(!dest._writableState || dest._writableState.needDrain))

ondrain();

}

// If the user pushes more data while we're writing to dest then we'll end up

// in ondata again. However, we only want to increase awaitDrain once because

// dest will only emit one 'drain' event for the multiple writes.

// => Introduce a guard on increasing awaitDrain.

var increasedAwaitDrain = false;

src.on('data', ondata);

function ondata(chunk) {

debug('ondata');

increasedAwaitDrain = false;

var ret = dest.write(chunk);

if (false === ret && !increasedAwaitDrain) {

// If the user unpiped during `dest.write()`, it is possible

// to get stuck in a permanently paused state if that write

// also returned false.

// => Check whether `dest` is still a piping destination.

if (((state.pipesCount === 1 && state.pipes === dest) ||

(state.pipesCount > 1 && state.pipes.indexOf(dest) !== -1)) &&

!cleanedUp) {

debug('false write response, pause', src._readableState.awaitDrain);

src._readableState.awaitDrain++;

increasedAwaitDrain = true;

}

src.pause();

}

// if the dest has an error, then stop piping into it.

// however, don't suppress the throwing behavior for this.

function onerror(er) {

debug('onerror', er);

unpipe();

dest.removeListener('error', onerror);

if (EE.listenerCount(dest, 'error') === 0)

dest.emit('error', er);

}

// Make sure our error handler is attached before userland ones.

prependListener(dest, 'error', onerror);

// Both close and finish should trigger unpipe, but only once.

function onclose() {

dest.removeListener('finish', onfinish);

unpipe();

}

dest.once('close', onclose);

function onfinish() {

debug('onfinish');

dest.removeListener('close', onclose);

unpipe();

}

dest.once('finish', onfinish);

function unpipe() {

debug('unpipe');

src.unpipe(dest);

}

// tell the dest that it's being piped to

dest.emit('pipe', src);

// start the flow if it hasn't been started already.

if (!state.flowing) {

debug('pipe resume');

src.resume();

}

return dest;

};

function pipeOnDrain(src) {

return function() {

var state = src._readableState;

debug('pipeOnDrain', state.awaitDrain);

if (state.awaitDrain)

state.awaitDrain--;

if (state.awaitDrain === 0 && EE.listenerCount(src, 'data')) {

state.flowing = true;

flow(src);

}

};

}

Readable.prototype.unpipe = function(dest) {

var state = this._readableState;

var unpipeInfo = { hasUnpiped: false };

// if we're not piping anywhere, then do nothing.

if (state.pipesCount === 0)

return this;

// just one destination. most common case.

if (state.pipesCount === 1) {

// passed in one, but it's not the right one.

if (dest && dest !== state.pipes)

return this;

if (!dest)

dest = state.pipes;

// got a match.

state.pipes = null;

state.pipesCount = 0;

state.flowing = false;

if (dest)

dest.emit('unpipe', this, unpipeInfo);

return this;

}

// slow case. multiple pipe destinations.

if (!dest) {

// remove all.

var dests = state.pipes;

var len = state.pipesCount;

state.pipes = null;

state.pipesCount = 0;

state.flowing = false;

for (var i = 0; i < len; i++)

dests[i].emit('unpipe', this, unpipeInfo);

return this;

}

// try to find the right one.

var index = state.pipes.indexOf(dest);

if (index === -1)

return this;

state.pipes.splice(index, 1);

state.pipesCount -= 1;

if (state.pipesCount === 1)

state.pipes = state.pipes[0];

dest.emit('unpipe', this, unpipeInfo);

return this;

};

// set up data events if they are asked for

// Ensure readable listeners eventually get something

Readable.prototype.on = function(ev, fn) {

const res = Stream.prototype.on.call(this, ev, fn);

if (ev === 'data') {

// Start flowing on next tick if stream isn't explicitly paused

if (this._readableState.flowing !== false)

this.resume();

} else if (ev === 'readable') {

const state = this._readableState;

if (!state.endEmitted && !state.readableListening) {

state.readableListening = state.needReadable = true;

state.emittedReadable = false;

if (!state.reading) {

process.nextTick(nReadingNextTick, this);

} else if (state.length) {

emitReadable(this);

}

return res;

};

Readable.prototype.addListener = Readable.prototype.on;

function nReadingNextTick(self) {

debug('readable nexttick read 0');

self.read(0);

}

// pause() and resume() are remnants of the legacy readable stream API

// If the user uses them, then switch into old mode.

Readable.prototype.resume = function() {

var state = this._readableState;

if (!state.flowing) {

debug('resume');

state.flowing = true;

resume(this, state);

}

return this;

};

function resume(stream, state) {

if (!state.resumeScheduled) {

state.resumeScheduled = true;

process.nextTick(resume_, stream, state);

}

function resume_(stream, state) {

if (!state.reading) {

debug('resume read 0');

stream.read(0);

}

state.resumeScheduled = false;

state.awaitDrain = 0;

stream.emit('resume');

flow(stream);

if (state.flowing && !state.reading)

stream.read(0);

}

Readable.prototype.pause = function() {

debug('call pause flowing=%j', this._readableState.flowing);

if (false !== this._readableState.flowing) {

debug('pause');

this._readableState.flowing = false;

this.emit('pause');

}

return this;

};

function flow(stream) {

const state = stream._readableState;

debug('flow', state.flowing);

while (state.flowing && stream.read() !== null);

}

// wrap an old-style stream as the async data source.

// This is *not* part of the readable stream interface.

// It is an ugly unfortunate mess of history.

Readable.prototype.wrap = function(stream) {

var state = this._readableState;

var paused = false;

var self = this;

stream.on('end', function() {

debug('wrapped end');

if (state.decoder && !state.ended) {

var chunk = state.decoder.end();

if (chunk && chunk.length)

self.push(chunk);

}

self.push(null);

});

stream.on('data', function(chunk) {

debug('wrapped data');

if (state.decoder)

chunk = state.decoder.write(chunk);

// don't skip over falsy values in objectMode

if (state.objectMode && (chunk === null || chunk === undefined))

return;

else if (!state.objectMode && (!chunk || !chunk.length))

return;

var ret = self.push(chunk);

if (!ret) {

paused = true;

stream.pause();

}

});

// proxy all the other methods.

// important when wrapping filters and duplexes.

for (var i in stream) {

if (this[i] === undefined && typeof stream[i] === 'function') {

this[i] = function(method) {

return function() {

return stream[method].apply(stream, arguments);

};

}(i);

}

// proxy certain important events.

for (var n = 0; n < kProxyEvents.length; n++) {

stream.on(kProxyEvents[n], self.emit.bind(self, kProxyEvents[n]));

}

// when we try to consume some more bytes, simply unpause the

// underlying stream.

self._read = function(n) {

debug('wrapped _read', n);

if (paused) {

paused = false;

stream.resume();

}

};

return self;

};

// exposed for testing purposes only.

Readable._fromList = fromList;

// Pluck off n bytes from an array of buffers.

// Length is the combined lengths of all the buffers in the list.

// This function is designed to be inlinable, so please take care when making

// changes to the function body.

function fromList(n, state) {

// nothing buffered

if (state.length === 0)

return null;

var ret;

if (state.objectMode)

ret = state.buffer.shift();

else if (!n || n >= state.length) {

// read it all, truncate the list

if (state.decoder)

ret = state.buffer.join('');

else if (state.buffer.length === 1)

ret = state.buffer.head.data;

else

ret = state.buffer.concat(state.length);

state.buffer.clear();

} else {

// read part of list

ret = fromListPartial(n, state.buffer, state.decoder);

}

return ret;

}

// Extracts only enough buffered data to satisfy the amount requested.

// This function is designed to be inlinable, so please take care when making

// changes to the function body.

function fromListPartial(n, list, hasStrings) {

var ret;

if (n < list.head.data.length) {

// slice is the same for buffers and strings

ret = list.head.data.slice(0, n);

list.head.data = list.head.data.slice(n);

} else if (n === list.head.data.length) {

// first chunk is a perfect match

ret = list.shift();

} else {

// result spans more than one buffer

ret = (hasStrings ?

copyFromBufferString(n, list) :

copyFromBuffer(n, list));

}

return ret;

}

// Copies a specified amount of characters from the list of buffered data

// chunks.

// This function is designed to be inlinable, so please take care when making

// changes to the function body.

function copyFromBufferString(n, list) {

var p = list.head;

var c = 1;

var ret = p.data;

n -= ret.length;

while (p = p.next) {

const str = p.data;

const nb = (n > str.length ? str.length : n);

if (nb === str.length)

ret += str;

else

ret += str.slice(0, n);

n -= nb;

if (n === 0) {

if (nb === str.length) {

++c;

if (p.next)

list.head = p.next;

else

list.head = list.tail = null;

} else {

list.head = p;

p.data = str.slice(nb);

}

break;

}

++c;

}

list.length -= c;

return ret;

}

// Copies a specified amount of bytes from the list of buffered data chunks.

// This function is designed to be inlinable, so please take care when making

// changes to the function body.

function copyFromBuffer(n, list) {

const ret = Buffer.allocUnsafe(n);

var p = list.head;

var c = 1;

p.data.copy(ret);

n -= p.data.length;

while (p = p.next) {

const buf = p.data;

const nb = (n > buf.length ? buf.length : n);

buf.copy(ret, ret.length - n, 0, nb);

n -= nb;

if (n === 0) {

if (nb === buf.length) {

++c;

if (p.next)

list.head = p.next;

else

list.head = list.tail = null;

} else {

list.head = p;

p.data = buf.slice(nb);

}

break;

}

++c;

}

list.length -= c;

return ret;

}

function endReadable(stream) {

var state = stream._readableState;

// If we get here before consuming all the bytes, then that is a

// bug in node. Should never happen.

if (state.length > 0)

throw new Error('"endReadable()" called on non-empty stream');

if (!state.endEmitted) {

state.ended = true;

process.nextTick(endReadableNT, state, stream);

}

function endReadableNT(state, stream) {

// Check that we didn't get one last unshift.

if (!state.endEmitted && state.length === 0) {

state.endEmitted = true;

stream.readable = false;

stream.emit('end');

}

node/lib/_stream_readable.js at master · anchnk/node · GitHub

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