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1019 lines
31 KiB
1019 lines
31 KiB
// Copyright Joyent, Inc. and other Node contributors.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a
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// copy of this software and associated documentation files (the
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// "Software"), to deal in the Software without restriction, including
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// without limitation the rights to use, copy, modify, merge, publish,
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// distribute, sublicense, and/or sell copies of the Software, and to permit
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// persons to whom the Software is furnished to do so, subject to the
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// following conditions:
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//
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// The above copyright notice and this permission notice shall be included
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// in all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
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// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
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// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
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// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
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// USE OR OTHER DEALINGS IN THE SOFTWARE.
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'use strict';
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/*<replacement>*/
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var pna = require('process-nextick-args');
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/*</replacement>*/
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module.exports = Readable;
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/*<replacement>*/
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var isArray = require('isarray');
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/*</replacement>*/
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/*<replacement>*/
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var Duplex;
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/*</replacement>*/
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Readable.ReadableState = ReadableState;
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/*<replacement>*/
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var EE = require('events').EventEmitter;
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var EElistenerCount = function (emitter, type) {
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return emitter.listeners(type).length;
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};
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/*</replacement>*/
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/*<replacement>*/
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var Stream = require('./internal/streams/stream');
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/*</replacement>*/
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/*<replacement>*/
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var Buffer = require('safe-buffer').Buffer;
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var OurUint8Array = (typeof global !== 'undefined' ? global : typeof window !== 'undefined' ? window : typeof self !== 'undefined' ? self : {}).Uint8Array || function () {};
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function _uint8ArrayToBuffer(chunk) {
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return Buffer.from(chunk);
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}
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function _isUint8Array(obj) {
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return Buffer.isBuffer(obj) || obj instanceof OurUint8Array;
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}
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/*</replacement>*/
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/*<replacement>*/
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var util = Object.create(require('core-util-is'));
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util.inherits = require('inherits');
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/*</replacement>*/
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/*<replacement>*/
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var debugUtil = require('util');
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var debug = void 0;
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if (debugUtil && debugUtil.debuglog) {
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debug = debugUtil.debuglog('stream');
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} else {
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debug = function () {};
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}
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/*</replacement>*/
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var BufferList = require('./internal/streams/BufferList');
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var destroyImpl = require('./internal/streams/destroy');
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var StringDecoder;
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util.inherits(Readable, Stream);
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var kProxyEvents = ['error', 'close', 'destroy', 'pause', 'resume'];
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function prependListener(emitter, event, fn) {
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// Sadly this is not cacheable as some libraries bundle their own
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// event emitter implementation with them.
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if (typeof emitter.prependListener === 'function') return emitter.prependListener(event, fn);
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// This is a hack to make sure that our error handler is attached before any
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// userland ones. NEVER DO THIS. This is here only because this code needs
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// to continue to work with older versions of Node.js that do not include
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// the prependListener() method. The goal is to eventually remove this hack.
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if (!emitter._events || !emitter._events[event]) emitter.on(event, fn);else if (isArray(emitter._events[event])) emitter._events[event].unshift(fn);else emitter._events[event] = [fn, emitter._events[event]];
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}
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function ReadableState(options, stream) {
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Duplex = Duplex || require('./_stream_duplex');
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options = options || {};
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// Duplex streams are both readable and writable, but share
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// the same options object.
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// However, some cases require setting options to different
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// values for the readable and the writable sides of the duplex stream.
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// These options can be provided separately as readableXXX and writableXXX.
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var isDuplex = stream instanceof Duplex;
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// object stream flag. Used to make read(n) ignore n and to
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// make all the buffer merging and length checks go away
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this.objectMode = !!options.objectMode;
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if (isDuplex) this.objectMode = this.objectMode || !!options.readableObjectMode;
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// the point at which it stops calling _read() to fill the buffer
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// Note: 0 is a valid value, means "don't call _read preemptively ever"
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var hwm = options.highWaterMark;
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var readableHwm = options.readableHighWaterMark;
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var defaultHwm = this.objectMode ? 16 : 16 * 1024;
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if (hwm || hwm === 0) this.highWaterMark = hwm;else if (isDuplex && (readableHwm || readableHwm === 0)) this.highWaterMark = readableHwm;else this.highWaterMark = defaultHwm;
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// cast to ints.
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this.highWaterMark = Math.floor(this.highWaterMark);
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// A linked list is used to store data chunks instead of an array because the
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// linked list can remove elements from the beginning faster than
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// array.shift()
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this.buffer = new BufferList();
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this.length = 0;
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this.pipes = null;
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this.pipesCount = 0;
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this.flowing = null;
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this.ended = false;
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this.endEmitted = false;
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this.reading = false;
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// a flag to be able to tell if the event 'readable'/'data' is emitted
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// immediately, or on a later tick. We set this to true at first, because
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// any actions that shouldn't happen until "later" should generally also
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// not happen before the first read call.
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this.sync = true;
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// whenever we return null, then we set a flag to say
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// that we're awaiting a 'readable' event emission.
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this.needReadable = false;
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this.emittedReadable = false;
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this.readableListening = false;
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this.resumeScheduled = false;
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// has it been destroyed
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this.destroyed = false;
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// Crypto is kind of old and crusty. Historically, its default string
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// encoding is 'binary' so we have to make this configurable.
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// Everything else in the universe uses 'utf8', though.
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this.defaultEncoding = options.defaultEncoding || 'utf8';
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// the number of writers that are awaiting a drain event in .pipe()s
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this.awaitDrain = 0;
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// if true, a maybeReadMore has been scheduled
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this.readingMore = false;
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this.decoder = null;
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this.encoding = null;
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if (options.encoding) {
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if (!StringDecoder) StringDecoder = require('string_decoder/').StringDecoder;
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this.decoder = new StringDecoder(options.encoding);
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this.encoding = options.encoding;
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}
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}
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function Readable(options) {
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Duplex = Duplex || require('./_stream_duplex');
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if (!(this instanceof Readable)) return new Readable(options);
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this._readableState = new ReadableState(options, this);
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// legacy
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this.readable = true;
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if (options) {
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if (typeof options.read === 'function') this._read = options.read;
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if (typeof options.destroy === 'function') this._destroy = options.destroy;
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}
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Stream.call(this);
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}
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Object.defineProperty(Readable.prototype, 'destroyed', {
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get: function () {
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if (this._readableState === undefined) {
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return false;
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}
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return this._readableState.destroyed;
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},
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set: function (value) {
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// we ignore the value if the stream
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// has not been initialized yet
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if (!this._readableState) {
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return;
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}
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// backward compatibility, the user is explicitly
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// managing destroyed
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this._readableState.destroyed = value;
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}
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});
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Readable.prototype.destroy = destroyImpl.destroy;
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Readable.prototype._undestroy = destroyImpl.undestroy;
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Readable.prototype._destroy = function (err, cb) {
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this.push(null);
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cb(err);
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};
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// Manually shove something into the read() buffer.
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// This returns true if the highWaterMark has not been hit yet,
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// similar to how Writable.write() returns true if you should
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// write() some more.
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Readable.prototype.push = function (chunk, encoding) {
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var state = this._readableState;
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var skipChunkCheck;
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if (!state.objectMode) {
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if (typeof chunk === 'string') {
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encoding = encoding || state.defaultEncoding;
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if (encoding !== state.encoding) {
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chunk = Buffer.from(chunk, encoding);
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encoding = '';
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}
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skipChunkCheck = true;
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}
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} else {
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skipChunkCheck = true;
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}
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return readableAddChunk(this, chunk, encoding, false, skipChunkCheck);
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};
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// Unshift should *always* be something directly out of read()
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Readable.prototype.unshift = function (chunk) {
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return readableAddChunk(this, chunk, null, true, false);
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};
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function readableAddChunk(stream, chunk, encoding, addToFront, skipChunkCheck) {
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var state = stream._readableState;
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if (chunk === null) {
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state.reading = false;
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onEofChunk(stream, state);
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} else {
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var er;
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if (!skipChunkCheck) er = chunkInvalid(state, chunk);
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if (er) {
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stream.emit('error', er);
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} else if (state.objectMode || chunk && chunk.length > 0) {
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if (typeof chunk !== 'string' && !state.objectMode && Object.getPrototypeOf(chunk) !== Buffer.prototype) {
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chunk = _uint8ArrayToBuffer(chunk);
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}
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if (addToFront) {
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if (state.endEmitted) stream.emit('error', new Error('stream.unshift() after end event'));else addChunk(stream, state, chunk, true);
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} else if (state.ended) {
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stream.emit('error', new Error('stream.push() after EOF'));
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} else {
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state.reading = false;
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if (state.decoder && !encoding) {
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chunk = state.decoder.write(chunk);
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if (state.objectMode || chunk.length !== 0) addChunk(stream, state, chunk, false);else maybeReadMore(stream, state);
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} else {
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addChunk(stream, state, chunk, false);
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}
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}
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} else if (!addToFront) {
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state.reading = false;
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}
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}
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return needMoreData(state);
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}
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function addChunk(stream, state, chunk, addToFront) {
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if (state.flowing && state.length === 0 && !state.sync) {
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stream.emit('data', chunk);
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stream.read(0);
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} else {
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// update the buffer info.
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state.length += state.objectMode ? 1 : chunk.length;
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if (addToFront) state.buffer.unshift(chunk);else state.buffer.push(chunk);
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if (state.needReadable) emitReadable(stream);
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}
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maybeReadMore(stream, state);
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}
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function chunkInvalid(state, chunk) {
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var er;
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if (!_isUint8Array(chunk) && typeof chunk !== 'string' && chunk !== undefined && !state.objectMode) {
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er = new TypeError('Invalid non-string/buffer chunk');
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}
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return er;
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}
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// if it's past the high water mark, we can push in some more.
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// Also, if we have no data yet, we can stand some
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// more bytes. This is to work around cases where hwm=0,
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// such as the repl. Also, if the push() triggered a
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// readable event, and the user called read(largeNumber) such that
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// needReadable was set, then we ought to push more, so that another
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// 'readable' event will be triggered.
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function needMoreData(state) {
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return !state.ended && (state.needReadable || state.length < state.highWaterMark || state.length === 0);
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}
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Readable.prototype.isPaused = function () {
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return this._readableState.flowing === false;
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};
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// backwards compatibility.
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Readable.prototype.setEncoding = function (enc) {
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if (!StringDecoder) StringDecoder = require('string_decoder/').StringDecoder;
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this._readableState.decoder = new StringDecoder(enc);
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this._readableState.encoding = enc;
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return this;
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};
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// Don't raise the hwm > 8MB
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var MAX_HWM = 0x800000;
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function computeNewHighWaterMark(n) {
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if (n >= MAX_HWM) {
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n = MAX_HWM;
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} else {
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// Get the next highest power of 2 to prevent increasing hwm excessively in
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// tiny amounts
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n--;
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n |= n >>> 1;
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n |= n >>> 2;
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n |= n >>> 4;
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n |= n >>> 8;
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n |= n >>> 16;
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n++;
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}
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return n;
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}
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// This function is designed to be inlinable, so please take care when making
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// changes to the function body.
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function howMuchToRead(n, state) {
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if (n <= 0 || state.length === 0 && state.ended) return 0;
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if (state.objectMode) return 1;
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if (n !== n) {
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// Only flow one buffer at a time
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if (state.flowing && state.length) return state.buffer.head.data.length;else return state.length;
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}
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// If we're asking for more than the current hwm, then raise the hwm.
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if (n > state.highWaterMark) state.highWaterMark = computeNewHighWaterMark(n);
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if (n <= state.length) return n;
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// Don't have enough
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if (!state.ended) {
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state.needReadable = true;
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return 0;
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}
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return state.length;
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}
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// you can override either this method, or the async _read(n) below.
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Readable.prototype.read = function (n) {
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debug('read', n);
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n = parseInt(n, 10);
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var state = this._readableState;
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var nOrig = n;
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if (n !== 0) state.emittedReadable = false;
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// if we're doing read(0) to trigger a readable event, but we
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// already have a bunch of data in the buffer, then just trigger
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// the 'readable' event and move on.
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if (n === 0 && state.needReadable && (state.length >= state.highWaterMark || state.ended)) {
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debug('read: emitReadable', state.length, state.ended);
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if (state.length === 0 && state.ended) endReadable(this);else emitReadable(this);
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return null;
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}
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n = howMuchToRead(n, state);
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// if we've ended, and we're now clear, then finish it up.
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if (n === 0 && state.ended) {
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if (state.length === 0) endReadable(this);
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return null;
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}
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// All the actual chunk generation logic needs to be
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// *below* the call to _read. The reason is that in certain
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// synthetic stream cases, such as passthrough streams, _read
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// may be a completely synchronous operation which may change
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// the state of the read buffer, providing enough data when
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// before there was *not* enough.
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//
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// So, the steps are:
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// 1. Figure out what the state of things will be after we do
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// a read from the buffer.
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//
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// 2. If that resulting state will trigger a _read, then call _read.
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// Note that this may be asynchronous, or synchronous. Yes, it is
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// deeply ugly to write APIs this way, but that still doesn't mean
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// that the Readable class should behave improperly, as streams are
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// designed to be sync/async agnostic.
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// Take note if the _read call is sync or async (ie, if the read call
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// has returned yet), so that we know whether or not it's safe to emit
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// 'readable' etc.
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//
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// 3. Actually pull the requested chunks out of the buffer and return.
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// if we need a readable event, then we need to do some reading.
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var doRead = state.needReadable;
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debug('need readable', doRead);
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// if we currently have less than the highWaterMark, then also read some
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if (state.length === 0 || state.length - n < state.highWaterMark) {
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doRead = true;
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debug('length less than watermark', doRead);
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}
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// however, if we've ended, then there's no point, and if we're already
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// reading, then it's unnecessary.
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if (state.ended || state.reading) {
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doRead = false;
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debug('reading or ended', doRead);
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} else if (doRead) {
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debug('do read');
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state.reading = true;
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state.sync = true;
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// if the length is currently zero, then we *need* a readable event.
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if (state.length === 0) state.needReadable = true;
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// call internal read method
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this._read(state.highWaterMark);
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state.sync = false;
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// If _read pushed data synchronously, then `reading` will be false,
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// and we need to re-evaluate how much data we can return to the user.
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if (!state.reading) n = howMuchToRead(nOrig, state);
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}
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var ret;
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if (n > 0) ret = fromList(n, state);else ret = null;
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if (ret === null) {
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state.needReadable = true;
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n = 0;
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} else {
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state.length -= n;
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}
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if (state.length === 0) {
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// If we have nothing in the buffer, then we want to know
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// as soon as we *do* get something into the buffer.
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if (!state.ended) state.needReadable = true;
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// If we tried to read() past the EOF, then emit end on the next tick.
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if (nOrig !== n && state.ended) endReadable(this);
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}
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if (ret !== null) this.emit('data', ret);
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return ret;
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};
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function onEofChunk(stream, state) {
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if (state.ended) return;
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if (state.decoder) {
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var chunk = state.decoder.end();
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if (chunk && chunk.length) {
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state.buffer.push(chunk);
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state.length += state.objectMode ? 1 : chunk.length;
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}
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}
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state.ended = true;
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// emit 'readable' now to make sure it gets picked up.
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emitReadable(stream);
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}
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// Don't emit readable right away in sync mode, because this can trigger
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// another read() call => stack overflow. This way, it might trigger
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|
// a nextTick recursion warning, but that's not so bad.
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|
function emitReadable(stream) {
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var state = stream._readableState;
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state.needReadable = false;
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if (!state.emittedReadable) {
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debug('emitReadable', state.flowing);
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state.emittedReadable = true;
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if (state.sync) pna.nextTick(emitReadable_, stream);else emitReadable_(stream);
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}
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}
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function emitReadable_(stream) {
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debug('emit readable');
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stream.emit('readable');
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flow(stream);
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}
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|
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// at this point, the user has presumably seen the 'readable' event,
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// 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;
|
|
pna.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) pna.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 && indexOf(state.pipes, dest) !== -1) && !cleanedUp) {
|
|
debug('false write response, pause', state.awaitDrain);
|
|
state.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 (EElistenerCount(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 && 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);
|
|
|
|
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') {
|
|
var state = this._readableState;
|
|
if (!state.endEmitted && !state.readableListening) {
|
|
state.readableListening = state.needReadable = true;
|
|
state.emittedReadable = false;
|
|
if (!state.reading) {
|
|
pna.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;
|
|
pna.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) {
|
|
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 (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], 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;
|
|
};
|
|
|
|
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 () {
|
|
return this._readableState.highWaterMark;
|
|
}
|
|
});
|
|
|
|
// 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) {
|
|
var str = p.data;
|
|
var 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) {
|
|
var ret = Buffer.allocUnsafe(n);
|
|
var p = list.head;
|
|
var c = 1;
|
|
p.data.copy(ret);
|
|
n -= p.data.length;
|
|
while (p = p.next) {
|
|
var buf = p.data;
|
|
var 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;
|
|
pna.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');
|
|
}
|
|
}
|
|
|
|
function indexOf(xs, x) {
|
|
for (var i = 0, l = xs.length; i < l; i++) {
|
|
if (xs[i] === x) return i;
|
|
}
|
|
return -1;
|
|
}
|