Current File : //lib/node_modules/npm/node_modules/readable-stream/lib/_stream_readable.js
// 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;
/*<replacement>*/
var Duplex;
/*</replacement>*/
Readable.ReadableState = ReadableState;
/*<replacement>*/
var EE = require('events').EventEmitter;
var EElistenerCount = function EElistenerCount(emitter, type) {
return emitter.listeners(type).length;
};
/*</replacement>*/
/*<replacement>*/
var Stream = require('./internal/streams/stream');
/*</replacement>*/
var Buffer = require('buffer').Buffer;
var OurUint8Array = global.Uint8Array || function () {};
function _uint8ArrayToBuffer(chunk) {
return Buffer.from(chunk);
}
function _isUint8Array(obj) {
return Buffer.isBuffer(obj) || obj instanceof OurUint8Array;
}
/*<replacement>*/
var debugUtil = require('util');
var debug;
if (debugUtil && debugUtil.debuglog) {
debug = debugUtil.debuglog('stream');
} else {
debug = function debug() {};
}
/*</replacement>*/
var BufferList = require('./internal/streams/buffer_list');
var destroyImpl = require('./internal/streams/destroy');
var _require = require('./internal/streams/state'),
getHighWaterMark = _require.getHighWaterMark;
var _require$codes = require('../errors').codes,
ERR_INVALID_ARG_TYPE = _require$codes.ERR_INVALID_ARG_TYPE,
ERR_STREAM_PUSH_AFTER_EOF = _require$codes.ERR_STREAM_PUSH_AFTER_EOF,
ERR_METHOD_NOT_IMPLEMENTED = _require$codes.ERR_METHOD_NOT_IMPLEMENTED,
ERR_STREAM_UNSHIFT_AFTER_END_EVENT = _require$codes.ERR_STREAM_UNSHIFT_AFTER_END_EVENT; // Lazy loaded to improve the startup performance.
var StringDecoder;
var createReadableStreamAsyncIterator;
var from;
require('inherits')(Readable, Stream);
var errorOrDestroy = destroyImpl.errorOrDestroy;
var 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); // 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, isDuplex) {
Duplex = Duplex || require('./_stream_duplex');
options = options || {}; // 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.
// These options can be provided separately as readableXXX and writableXXX.
if (typeof isDuplex !== 'boolean') isDuplex = stream instanceof Duplex; // 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 (isDuplex) 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"
this.highWaterMark = getHighWaterMark(this, options, 'readableHighWaterMark', isDuplex); // 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;
this.paused = true; // Should close be emitted on destroy. Defaults to true.
this.emitClose = options.emitClose !== false; // Should .destroy() be called after 'end' (and potentially 'finish')
this.autoDestroy = !!options.autoDestroy; // has it been destroyed
this.destroyed = 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) {
Duplex = Duplex || require('./_stream_duplex');
if (!(this instanceof Readable)) return new Readable(options); // Checking for a Stream.Duplex instance is faster here instead of inside
// the ReadableState constructor, at least with V8 6.5
var isDuplex = this instanceof Duplex;
this._readableState = new ReadableState(options, this, isDuplex); // legacy
this.readable = true;
if (options) {
if (typeof options.read === 'function') this._read = options.read;
if (typeof options.destroy === 'function') this._destroy = options.destroy;
}
Stream.call(this);
}
Object.defineProperty(Readable.prototype, 'destroyed', {
// making it explicit this property is not enumerable
// because otherwise some prototype manipulation in
// userland will fail
enumerable: false,
get: function get() {
if (this._readableState === undefined) {
return false;
}
return this._readableState.destroyed;
},
set: function set(value) {
// we ignore the value if the stream
// has not been initialized yet
if (!this._readableState) {
return;
} // backward compatibility, the user is explicitly
// managing destroyed
this._readableState.destroyed = value;
}
});
Readable.prototype.destroy = destroyImpl.destroy;
Readable.prototype._undestroy = destroyImpl.undestroy;
Readable.prototype._destroy = function (err, cb) {
cb(err);
}; // 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;
var skipChunkCheck;
if (!state.objectMode) {
if (typeof chunk === 'string') {
encoding = encoding || state.defaultEncoding;
if (encoding !== state.encoding) {
chunk = Buffer.from(chunk, encoding);
encoding = '';
}
skipChunkCheck = true;
}
} else {
skipChunkCheck = true;
}
return readableAddChunk(this, chunk, encoding, false, skipChunkCheck);
}; // Unshift should *always* be something directly out of read()
Readable.prototype.unshift = function (chunk) {
return readableAddChunk(this, chunk, null, true, false);
};
function readableAddChunk(stream, chunk, encoding, addToFront, skipChunkCheck) {
debug('readableAddChunk', chunk);
var state = stream._readableState;
if (chunk === null) {
state.reading = false;
onEofChunk(stream, state);
} else {
var er;
if (!skipChunkCheck) er = chunkInvalid(state, chunk);
if (er) {
errorOrDestroy(stream, er);
} else if (state.objectMode || chunk && chunk.length > 0) {
if (typeof chunk !== 'string' && !state.objectMode && Object.getPrototypeOf(chunk) !== Buffer.prototype) {
chunk = _uint8ArrayToBuffer(chunk);
}
if (addToFront) {
if (state.endEmitted) errorOrDestroy(stream, new ERR_STREAM_UNSHIFT_AFTER_END_EVENT());else addChunk(stream, state, chunk, true);
} else if (state.ended) {
errorOrDestroy(stream, new ERR_STREAM_PUSH_AFTER_EOF());
} else if (state.destroyed) {
return false;
} else {
state.reading = false;
if (state.decoder && !encoding) {
chunk = state.decoder.write(chunk);
if (state.objectMode || chunk.length !== 0) addChunk(stream, state, chunk, false);else maybeReadMore(stream, state);
} else {
addChunk(stream, state, chunk, false);
}
}
} else if (!addToFront) {
state.reading = false;
maybeReadMore(stream, state);
}
} // We can push more data if we are below the highWaterMark.
// 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.
return !state.ended && (state.length < state.highWaterMark || state.length === 0);
}
function addChunk(stream, state, chunk, addToFront) {
if (state.flowing && state.length === 0 && !state.sync) {
state.awaitDrain = 0;
stream.emit('data', chunk);
} 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);
}
function chunkInvalid(state, chunk) {
var er;
if (!_isUint8Array(chunk) && typeof chunk !== 'string' && chunk !== undefined && !state.objectMode) {
er = new ERR_INVALID_ARG_TYPE('chunk', ['string', 'Buffer', 'Uint8Array'], chunk);
}
return er;
}
Readable.prototype.isPaused = function () {
return this._readableState.flowing === false;
}; // backwards compatibility.
Readable.prototype.setEncoding = function (enc) {
if (!StringDecoder) StringDecoder = require('string_decoder/').StringDecoder;
var decoder = new StringDecoder(enc);
this._readableState.decoder = decoder; // If setEncoding(null), decoder.encoding equals utf8
this._readableState.encoding = this._readableState.decoder.encoding; // Iterate over current buffer to convert already stored Buffers:
var p = this._readableState.buffer.head;
var content = '';
while (p !== null) {
content += decoder.write(p.data);
p = p.next;
}
this._readableState.buffer.clear();
if (content !== '') this._readableState.buffer.push(content);
this._readableState.length = content.length;
return this;
}; // Don't raise the hwm > 1GB
var MAX_HWM = 0x40000000;
function computeNewHighWaterMark(n) {
if (n >= MAX_HWM) {
// TODO(ronag): Throw ERR_VALUE_OUT_OF_RANGE.
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.highWaterMark !== 0 ? state.length >= state.highWaterMark : state.length > 0) || 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 = state.length <= state.highWaterMark;
n = 0;
} else {
state.length -= n;
state.awaitDrain = 0;
}
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 onEofChunk(stream, state) {
debug('onEofChunk');
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;
if (state.sync) {
// if we are sync, wait until next tick to emit the data.
// Otherwise we risk emitting data in the flow()
// the readable code triggers during a read() call
emitReadable(stream);
} else {
// emit 'readable' now to make sure it gets picked up.
state.needReadable = false;
if (!state.emittedReadable) {
state.emittedReadable = true;
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;
debug('emitReadable', state.needReadable, state.emittedReadable);
state.needReadable = false;
if (!state.emittedReadable) {
debug('emitReadable', state.flowing);
state.emittedReadable = true;
process.nextTick(emitReadable_, stream);
}
}
function emitReadable_(stream) {
var state = stream._readableState;
debug('emitReadable_', state.destroyed, state.length, state.ended);
if (!state.destroyed && (state.length || state.ended)) {
stream.emit('readable');
state.emittedReadable = false;
} // The stream needs another readable event if
// 1. It is not flowing, as the flow mechanism will take
// care of it.
// 2. It is not ended.
// 3. It is below the highWaterMark, so we can schedule
// another readable later.
state.needReadable = !state.flowing && !state.ended && state.length <= state.highWaterMark;
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) {
// Attempt to read more data if we should.
//
// The conditions for reading more data are (one of):
// - Not enough data buffered (state.length < state.highWaterMark). The loop
// is responsible for filling the buffer with enough data if such data
// is available. If highWaterMark is 0 and we are not in the flowing mode
// we should _not_ attempt to buffer any extra data. We'll get more data
// when the stream consumer calls read() instead.
// - No data in the buffer, and the stream is in flowing mode. In this mode
// the loop below is responsible for ensuring read() is called. Failing to
// call read here would abort the flow and there's no other mechanism for
// continuing the flow if the stream consumer has just subscribed to the
// 'data' event.
//
// In addition to the above conditions to keep reading data, the following
// conditions prevent the data from being read:
// - The stream has ended (state.ended).
// - There is already a pending 'read' operation (state.reading). This is a
// case where the the stream has called the implementation defined _read()
// method, but they are processing the call asynchronously and have _not_
// called push() with new data. In this case we skip performing more
// read()s. The execution ends in this method again after the _read() ends
// up calling push() with more data.
while (!state.reading && !state.ended && (state.length < state.highWaterMark || state.flowing && state.length === 0)) {
var len = state.length;
debug('maybeReadMore read 0');
stream.read(0);
if (len === state.length) // didn't get any data, stop spinning.
break;
}
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) {
errorOrDestroy(this, new ERR_METHOD_NOT_IMPLEMENTED('_read()'));
};
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();
}
src.on('data', ondata);
function ondata(chunk) {
debug('ondata');
var ret = dest.write(chunk);
debug('dest.write', ret);
if (ret === false) {
// 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 && indexOf(state.pipes, dest) !== -1) && !cleanedUp) {
debug('false write response, pause', state.awaitDrain);
state.awaitDrain++;
}
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 (EElistenerCount(dest, 'error') === 0) errorOrDestroy(dest, 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 pipeOnDrainFunctionResult() {
var state = src._readableState;
debug('pipeOnDrain', state.awaitDrain);
if (state.awaitDrain) state.awaitDrain--;
if (state.awaitDrain === 0 && EElistenerCount(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, {
hasUnpiped: false
});
}
return this;
} // try to find the right one.
var index = indexOf(state.pipes, 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) {
var res = Stream.prototype.on.call(this, ev, fn);
var state = this._readableState;
if (ev === 'data') {
// update readableListening so that resume() may be a no-op
// a few lines down. This is needed to support once('readable').
state.readableListening = this.listenerCount('readable') > 0; // Try start flowing on next tick if stream isn't explicitly paused
if (state.flowing !== false) this.resume();
} else if (ev === 'readable') {
if (!state.endEmitted && !state.readableListening) {
state.readableListening = state.needReadable = true;
state.flowing = false;
state.emittedReadable = false;
debug('on readable', state.length, state.reading);
if (state.length) {
emitReadable(this);
} else if (!state.reading) {
process.nextTick(nReadingNextTick, this);
}
}
}
return res;
};
Readable.prototype.addListener = Readable.prototype.on;
Readable.prototype.removeListener = function (ev, fn) {
var res = Stream.prototype.removeListener.call(this, ev, fn);
if (ev === 'readable') {
// We need to check if there is someone still listening to
// readable and reset the state. However this needs to happen
// after readable has been emitted but before I/O (nextTick) to
// support once('readable', fn) cycles. This means that calling
// resume within the same tick will have no
// effect.
process.nextTick(updateReadableListening, this);
}
return res;
};
Readable.prototype.removeAllListeners = function (ev) {
var res = Stream.prototype.removeAllListeners.apply(this, arguments);
if (ev === 'readable' || ev === undefined) {
// We need to check if there is someone still listening to
// readable and reset the state. However this needs to happen
// after readable has been emitted but before I/O (nextTick) to
// support once('readable', fn) cycles. This means that calling
// resume within the same tick will have no
// effect.
process.nextTick(updateReadableListening, this);
}
return res;
};
function updateReadableListening(self) {
var state = self._readableState;
state.readableListening = self.listenerCount('readable') > 0;
if (state.resumeScheduled && !state.paused) {
// flowing needs to be set to true now, otherwise
// the upcoming resume will not flow.
state.flowing = true; // crude way to check if we should resume
} else if (self.listenerCount('data') > 0) {
self.resume();
}
}
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'); // we flow only if there is no one listening
// for readable, but we still have to call
// resume()
state.flowing = !state.readableListening;
resume(this, state);
}
state.paused = false;
return this;
};
function resume(stream, state) {
if (!state.resumeScheduled) {
state.resumeScheduled = true;
process.nextTick(resume_, stream, state);
}
}
function resume_(stream, state) {
debug('resume', state.reading);
if (!state.reading) {
stream.read(0);
}
state.resumeScheduled = false;
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 (this._readableState.flowing !== false) {
debug('pause');
this._readableState.flowing = false;
this.emit('pause');
}
this._readableState.paused = true;
return this;
};
function flow(stream) {
var 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 _this = this;
var state = this._readableState;
var paused = false;
stream.on('end', function () {
debug('wrapped end');
if (state.decoder && !state.ended) {
var chunk = state.decoder.end();
if (chunk && chunk.length) _this.push(chunk);
}
_this.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 = _this.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 methodWrap(method) {
return function methodWrapReturnFunction() {
return stream[method].apply(stream, arguments);
};
}(i);
}
} // proxy certain important events.
for (var n = 0; n < kProxyEvents.length; n++) {
stream.on(kProxyEvents[n], this.emit.bind(this, kProxyEvents[n]));
} // when we try to consume some more bytes, simply unpause the
// underlying stream.
this._read = function (n) {
debug('wrapped _read', n);
if (paused) {
paused = false;
stream.resume();
}
};
return this;
};
if (typeof Symbol === 'function') {
Readable.prototype[Symbol.asyncIterator] = function () {
if (createReadableStreamAsyncIterator === undefined) {
createReadableStreamAsyncIterator = require('./internal/streams/async_iterator');
}
return createReadableStreamAsyncIterator(this);
};
}
Object.defineProperty(Readable.prototype, 'readableHighWaterMark', {
// making it explicit this property is not enumerable
// because otherwise some prototype manipulation in
// userland will fail
enumerable: false,
get: function get() {
return this._readableState.highWaterMark;
}
});
Object.defineProperty(Readable.prototype, 'readableBuffer', {
// making it explicit this property is not enumerable
// because otherwise some prototype manipulation in
// userland will fail
enumerable: false,
get: function get() {
return this._readableState && this._readableState.buffer;
}
});
Object.defineProperty(Readable.prototype, 'readableFlowing', {
// making it explicit this property is not enumerable
// because otherwise some prototype manipulation in
// userland will fail
enumerable: false,
get: function get() {
return this._readableState.flowing;
},
set: function set(state) {
if (this._readableState) {
this._readableState.flowing = state;
}
}
}); // exposed for testing purposes only.
Readable._fromList = fromList;
Object.defineProperty(Readable.prototype, 'readableLength', {
// making it explicit this property is not enumerable
// because otherwise some prototype manipulation in
// userland will fail
enumerable: false,
get: function get() {
return this._readableState.length;
}
}); // 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.first();else ret = state.buffer.concat(state.length);
state.buffer.clear();
} else {
// read part of list
ret = state.buffer.consume(n, state.decoder);
}
return ret;
}
function endReadable(stream) {
var state = stream._readableState;
debug('endReadable', state.endEmitted);
if (!state.endEmitted) {
state.ended = true;
process.nextTick(endReadableNT, state, stream);
}
}
function endReadableNT(state, stream) {
debug('endReadableNT', state.endEmitted, state.length); // Check that we didn't get one last unshift.
if (!state.endEmitted && state.length === 0) {
state.endEmitted = true;
stream.readable = false;
stream.emit('end');
if (state.autoDestroy) {
// In case of duplex streams we need a way to detect
// if the writable side is ready for autoDestroy as well
var wState = stream._writableState;
if (!wState || wState.autoDestroy && wState.finished) {
stream.destroy();
}
}
}
}
if (typeof Symbol === 'function') {
Readable.from = function (iterable, opts) {
if (from === undefined) {
from = require('./internal/streams/from');
}
return from(Readable, iterable, opts);
};
}
function indexOf(xs, x) {
for (var i = 0, l = xs.length; i < l; i++) {
if (xs[i] === x) return i;
}
return -1;
}
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