node_modules

1 files changed, 328 insertions, 342 deletions

diff --git a/node_modules/readable-stream/lib/_stream_readable.js b/node_modules/readable-stream/lib/_stream_readable.js
index 19ab35889..208cc65f1 100644
--- a/node_modules/readable-stream/lib/_stream_readable.js
+++ b/node_modules/readable-stream/lib/_stream_readable.js
@@ -1,82 +1,98 @@
-// 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 isArray = require('isarray');
+var processNextTick = require('process-nextick-args');
 /*</replacement>*/
 
-
 /*<replacement>*/
-var Buffer = require('buffer').Buffer;
+var isArray = require('isarray');
 /*</replacement>*/
 
 Readable.ReadableState = ReadableState;
 
+/*<replacement>*/
 var EE = require('events').EventEmitter;
 
-/*<replacement>*/
-if (!EE.listenerCount) EE.listenerCount = function(emitter, type) {
+var EElistenerCount = function (emitter, type) {
   return emitter.listeners(type).length;
 };
 /*</replacement>*/
 
-var Stream = require('stream');
+/*<replacement>*/
+var Stream;
+(function () {
+  try {
+    Stream = require('st' + 'ream');
+  } catch (_) {} finally {
+    if (!Stream) Stream = require('events').EventEmitter;
+  }
+})();
+/*</replacement>*/
+
+var Buffer = require('buffer').Buffer;
+/*<replacement>*/
+var bufferShim = require('buffer-shims');
+/*</replacement>*/
 
 /*<replacement>*/
 var util = require('core-util-is');
 util.inherits = require('inherits');
 /*</replacement>*/
 
-var StringDecoder;
-
-
 /*<replacement>*/
-var debug = require('util');
-if (debug && debug.debuglog) {
-  debug = debug.debuglog('stream');
+var debugUtil = require('util');
+var debug = void 0;
+if (debugUtil && debugUtil.debuglog) {
+  debug = debugUtil.debuglog('stream');
 } else {
   debug = function () {};
 }
 /*</replacement>*/
 
+var BufferList = require('./internal/streams/BufferList');
+var StringDecoder;
 
 util.inherits(Readable, Stream);
 
+function prependListener(emitter, event, fn) {
+  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 (isArray(emitter._events[event])) emitter._events[event].unshift(fn);else emitter._events[event] = [fn, emitter._events[event]];
+  }
+}
+
+var Duplex;
 function ReadableState(options, stream) {
-  var Duplex = require('./_stream_duplex');
+  Duplex = Duplex || require('./_stream_duplex');
 
   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 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 = options.objectMode ? 16 : 16 * 1024;
-  this.highWaterMark = (hwm || hwm === 0) ? hwm : defaultHwm;
+  var defaultHwm = this.objectMode ? 16 : 16 * 1024;
+  this.highWaterMark = hwm || hwm === 0 ? hwm : defaultHwm;
 
   // cast to ints.
-  this.highWaterMark = ~~this.highWaterMark;
+  this.highWaterMark = ~ ~this.highWaterMark;
 
-  this.buffer = [];
+  // 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;
@@ -96,14 +112,7 @@ function ReadableState(options, stream) {
   this.needReadable = false;
   this.emittedReadable = false;
   this.readableListening = false;
-
-
-  // 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 Duplex)
-    this.objectMode = this.objectMode || !!options.readableObjectMode;
+  this.resumeScheduled = false;
 
   // Crypto is kind of old and crusty.  Historically, its default string
   // encoding is 'binary' so we have to make this configurable.
@@ -123,24 +132,25 @@ function ReadableState(options, stream) {
   this.decoder = null;
   this.encoding = null;
   if (options.encoding) {
-    if (!StringDecoder)
-      StringDecoder = require('string_decoder/').StringDecoder;
+    if (!StringDecoder) StringDecoder = require('string_decoder/').StringDecoder;
     this.decoder = new StringDecoder(options.encoding);
     this.encoding = options.encoding;
   }
 }
 
+var Duplex;
 function Readable(options) {
-  var Duplex = require('./_stream_duplex');
+  Duplex = Duplex || require('./_stream_duplex');
 
-  if (!(this instanceof Readable))
-    return new 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);
 }
 
@@ -148,13 +158,13 @@ function Readable(options) {
 // 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) {
+Readable.prototype.push = function (chunk, encoding) {
   var state = this._readableState;
 
-  if (util.isString(chunk) && !state.objectMode) {
+  if (!state.objectMode && typeof chunk === 'string') {
     encoding = encoding || state.defaultEncoding;
     if (encoding !== state.encoding) {
-      chunk = new Buffer(chunk, encoding);
+      chunk = bufferShim.from(chunk, encoding);
       encoding = '';
     }
   }
@@ -163,47 +173,52 @@ Readable.prototype.push = function(chunk, encoding) {
 };
 
 // Unshift should *always* be something directly out of read()
-Readable.prototype.unshift = function(chunk) {
+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 (util.isNullOrUndefined(chunk)) {
+  } else if (chunk === null) {
     state.reading = false;
-    if (!state.ended)
-      onEofChunk(stream, state);
+    onEofChunk(stream, state);
   } else if (state.objectMode || chunk && chunk.length > 0) {
     if (state.ended && !addToFront) {
       var e = new Error('stream.push() after EOF');
       stream.emit('error', e);
     } else if (state.endEmitted && addToFront) {
-      var e = new Error('stream.unshift() after end event');
-      stream.emit('error', e);
+      var _e = new Error('stream.unshift() after end event');
+      stream.emit('error', _e);
     } else {
-      if (state.decoder && !addToFront && !encoding)
+      var skipAdd;
+      if (state.decoder && !addToFront && !encoding) {
         chunk = state.decoder.write(chunk);
+        skipAdd = !state.objectMode && chunk.length === 0;
+      }
 
-      if (!addToFront)
-        state.reading = false;
-
-      // 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);
+      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);
@@ -215,8 +230,6 @@ function readableAddChunk(stream, state, chunk, encoding, addToFront) {
   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,
@@ -225,92 +238,71 @@ function readableAddChunk(stream, state, chunk, encoding, addToFront) {
 // 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);
+  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;
+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 > 128MB
+// Don't raise the hwm > 8MB
 var MAX_HWM = 0x800000;
-function roundUpToNextPowerOf2(n) {
+function computeNewHighWaterMark(n) {
   if (n >= MAX_HWM) {
     n = MAX_HWM;
   } else {
-    // Get the next highest power of 2
+    // Get the next highest power of 2 to prevent increasing hwm excessively in
+    // tiny amounts
     n--;
-    for (var p = 1; p < 32; p <<= 1) n |= n >> p;
+    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 (state.length === 0 && state.ended)
+  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;
-
-  if (state.objectMode)
-    return n === 0 ? 0 : 1;
-
-  if (isNaN(n) || util.isNull(n)) {
-    // only flow one buffer at a time
-    if (state.flowing && state.buffer.length)
-      return state.buffer[0].length;
-    else
-      return state.length;
   }
-
-  if (n <= 0)
-    return 0;
-
-  // If we're asking for more than the target buffer level,
-  // then raise the water mark.  Bump up to the next highest
-  // power of 2, to prevent increasing it excessively in tiny
-  // amounts.
-  if (n > state.highWaterMark)
-    state.highWaterMark = roundUpToNextPowerOf2(n);
-
-  // don't have that much.  return null, unless we've ended.
-  if (n > state.length) {
-    if (!state.ended) {
-      state.needReadable = true;
-      return 0;
-    } else
-      return state.length;
-  }
-
-  return n;
+  return state.length;
 }
 
 // you can override either this method, or the async _read(n) below.
-Readable.prototype.read = function(n) {
+Readable.prototype.read = function (n) {
   debug('read', n);
+  n = parseInt(n, 10);
   var state = this._readableState;
   var nOrig = n;
 
-  if (!util.isNumber(n) || n > 0)
-    state.emittedReadable = false;
+  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)) {
+  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);
+    if (state.length === 0 && state.ended) endReadable(this);else emitReadable(this);
     return null;
   }
 
@@ -318,8 +310,7 @@ Readable.prototype.read = function(n) {
 
   // if we've ended, and we're now clear, then finish it up.
   if (n === 0 && state.ended) {
-    if (state.length === 0)
-      endReadable(this);
+    if (state.length === 0) endReadable(this);
     return null;
   }
 
@@ -360,67 +351,55 @@ Readable.prototype.read = function(n) {
   if (state.ended || state.reading) {
     doRead = false;
     debug('reading or ended', doRead);
-  }
-
-  if (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;
+    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);
   }
 
-  // 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 (doRead && !state.reading)
-    n = howMuchToRead(nOrig, state);
-
   var ret;
-  if (n > 0)
-    ret = fromList(n, state);
-  else
-    ret = null;
+  if (n > 0) ret = fromList(n, state);else ret = null;
 
-  if (util.isNull(ret)) {
+  if (ret === null) {
     state.needReadable = true;
     n = 0;
+  } else {
+    state.length -= n;
   }
 
-  state.length -= n;
-
-  // If we have nothing in the buffer, then we want to know
-  // as soon as we *do* get something into the buffer.
-  if (state.length === 0 && !state.ended)
-    state.needReadable = true;
+  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 && state.length === 0)
-    endReadable(this);
+    // If we tried to read() past the EOF, then emit end on the next tick.
+    if (nOrig !== n && state.ended) endReadable(this);
+  }
 
-  if (!util.isNull(ret))
-    this.emit('data', ret);
+  if (ret !== null) this.emit('data', ret);
 
   return ret;
 };
 
 function chunkInvalid(state, chunk) {
   var er = null;
-  if (!util.isBuffer(chunk) &&
-      !util.isString(chunk) &&
-      !util.isNullOrUndefined(chunk) &&
-      !state.objectMode) {
+  if (!Buffer.isBuffer(chunk) && 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.decoder && !state.ended) {
+  if (state.ended) return;
+  if (state.decoder) {
     var chunk = state.decoder.end();
     if (chunk && chunk.length) {
       state.buffer.push(chunk);
@@ -442,12 +421,7 @@ function emitReadable(stream) {
   if (!state.emittedReadable) {
     debug('emitReadable', state.flowing);
     state.emittedReadable = true;
-    if (state.sync)
-      process.nextTick(function() {
-        emitReadable_(stream);
-      });
-    else
-      emitReadable_(stream);
+    if (state.sync) processNextTick(emitReadable_, stream);else emitReadable_(stream);
   }
 }
 
@@ -457,7 +431,6 @@ function emitReadable_(stream) {
   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
@@ -467,23 +440,18 @@ function emitReadable_(stream) {
 function maybeReadMore(stream, state) {
   if (!state.readingMore) {
     state.readingMore = true;
-    process.nextTick(function() {
-      maybeReadMore_(stream, state);
-    });
+    processNextTick(maybeReadMore_, stream, state);
   }
 }
 
 function maybeReadMore_(stream, state) {
   var len = state.length;
-  while (!state.reading && !state.flowing && !state.ended &&
-         state.length < state.highWaterMark) {
+  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;
+      break;else len = state.length;
   }
   state.readingMore = false;
 }
@@ -492,11 +460,11 @@ function maybeReadMore_(stream, state) {
 // 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) {
+Readable.prototype._read = function (n) {
   this.emit('error', new Error('not implemented'));
 };
 
-Readable.prototype.pipe = function(dest, pipeOpts) {
+Readable.prototype.pipe = function (dest, pipeOpts) {
   var src = this;
   var state = this._readableState;
 
@@ -514,15 +482,10 @@ Readable.prototype.pipe = function(dest, pipeOpts) {
   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 doEnd = (!pipeOpts || pipeOpts.end !== false) && dest !== process.stdout && dest !== process.stderr;
 
   var endFn = doEnd ? onend : cleanup;
-  if (state.endEmitted)
-    process.nextTick(endFn);
-  else
-    src.once('end', endFn);
+  if (state.endEmitted) processNextTick(endFn);else src.once('end', endFn);
 
   dest.on('unpipe', onunpipe);
   function onunpipe(readable) {
@@ -544,6 +507,7 @@ Readable.prototype.pipe = function(dest, pipeOpts) {
   var ondrain = pipeOnDrain(src);
   dest.on('drain', ondrain);
 
+  var cleanedUp = false;
   function cleanup() {
     debug('cleanup');
     // cleanup event handlers once the pipe is broken
@@ -556,24 +520,36 @@ Readable.prototype.pipe = function(dest, pipeOpts) {
     src.removeListener('end', cleanup);
     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 (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) {
-      debug('false write response, pause',
-            src._readableState.awaitDrain);
-      src._readableState.awaitDrain++;
+    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', src._readableState.awaitDrain);
+        src._readableState.awaitDrain++;
+        increasedAwaitDrain = true;
+      }
       src.pause();
     }
   }
@@ -584,19 +560,11 @@ Readable.prototype.pipe = function(dest, pipeOpts) {
     debug('onerror', er);
     unpipe();
     dest.removeListener('error', onerror);
-    if (EE.listenerCount(dest, 'error') === 0)
-      dest.emit('error', er);
+    if (EElistenerCount(dest, 'error') === 0) dest.emit('error', er);
   }
-  // This is a brutally ugly hack to make sure that our error handler
-  // is attached before any userland ones.  NEVER DO THIS.
-  if (!dest._events || !dest._events.error)
-    dest.on('error', onerror);
-  else if (isArray(dest._events.error))
-    dest._events.error.unshift(onerror);
-  else
-    dest._events.error = [onerror, dest._events.error];
-
 
+  // 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() {
@@ -629,41 +597,35 @@ Readable.prototype.pipe = function(dest, pipeOpts) {
 };
 
 function pipeOnDrain(src) {
-  return function() {
+  return function () {
     var state = src._readableState;
     debug('pipeOnDrain', state.awaitDrain);
-    if (state.awaitDrain)
-      state.awaitDrain--;
-    if (state.awaitDrain === 0 && EE.listenerCount(src, 'data')) {
+    if (state.awaitDrain) state.awaitDrain--;
+    if (state.awaitDrain === 0 && EElistenerCount(src, 'data')) {
       state.flowing = true;
       flow(src);
     }
   };
 }
 
-
-Readable.prototype.unpipe = function(dest) {
+Readable.prototype.unpipe = function (dest) {
   var state = this._readableState;
 
   // if we're not piping anywhere, then do nothing.
-  if (state.pipesCount === 0)
-    return this;
+  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) return this;
 
-    if (!dest)
-      dest = state.pipes;
+    if (!dest) dest = state.pipes;
 
     // got a match.
     state.pipes = null;
     state.pipesCount = 0;
     state.flowing = false;
-    if (dest)
-      dest.emit('unpipe', this);
+    if (dest) dest.emit('unpipe', this);
     return this;
   }
 
@@ -677,20 +639,18 @@ Readable.prototype.unpipe = function(dest) {
     state.pipesCount = 0;
     state.flowing = false;
 
-    for (var i = 0; i < len; i++)
-      dests[i].emit('unpipe', this);
-    return this;
+    for (var _i = 0; _i < len; _i++) {
+      dests[_i].emit('unpipe', this);
+    }return this;
   }
 
   // try to find the right one.
   var i = indexOf(state.pipes, dest);
-  if (i === -1)
-    return this;
+  if (i === -1) return this;
 
   state.pipes.splice(i, 1);
   state.pipesCount -= 1;
-  if (state.pipesCount === 1)
-    state.pipes = state.pipes[0];
+  if (state.pipesCount === 1) state.pipes = state.pipes[0];
 
   dest.emit('unpipe', this);
 
@@ -699,27 +659,19 @@ Readable.prototype.unpipe = function(dest) {
 
 // set up data events if they are asked for
 // Ensure readable listeners eventually get something
-Readable.prototype.on = function(ev, fn) {
+Readable.prototype.on = function (ev, fn) {
   var res = Stream.prototype.on.call(this, ev, fn);
 
-  // If listening to data, and it has not explicitly been paused,
-  // then call resume to start the flow of data on the next tick.
-  if (ev === 'data' && false !== this._readableState.flowing) {
-    this.resume();
-  }
-
-  if (ev === 'readable' && this.readable) {
+  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.readableListening) {
-      state.readableListening = true;
+    if (!state.endEmitted && !state.readableListening) {
+      state.readableListening = state.needReadable = true;
       state.emittedReadable = false;
-      state.needReadable = true;
       if (!state.reading) {
-        var self = this;
-        process.nextTick(function() {
-          debug('readable nexttick read 0');
-          self.read(0);
-        });
+        processNextTick(nReadingNextTick, this);
       } else if (state.length) {
         emitReadable(this, state);
       }
@@ -730,17 +682,18 @@ Readable.prototype.on = function(ev, fn) {
 };
 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() {
+Readable.prototype.resume = function () {
   var state = this._readableState;
   if (!state.flowing) {
     debug('resume');
     state.flowing = true;
-    if (!state.reading) {
-      debug('resume read 0');
-      this.read(0);
-    }
     resume(this, state);
   }
   return this;
@@ -749,21 +702,24 @@ Readable.prototype.resume = function() {
 function resume(stream, state) {
   if (!state.resumeScheduled) {
     state.resumeScheduled = true;
-    process.nextTick(function() {
-      resume_(stream, state);
-    });
+    processNextTick(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);
+  if (state.flowing && !state.reading) stream.read(0);
 }
 
-Readable.prototype.pause = function() {
+Readable.prototype.pause = function () {
   debug('call pause flowing=%j', this._readableState.flowing);
   if (false !== this._readableState.flowing) {
     debug('pause');
@@ -776,38 +732,33 @@ Readable.prototype.pause = function() {
 function flow(stream) {
   var state = stream._readableState;
   debug('flow', state.flowing);
-  if (state.flowing) {
-    do {
-      var chunk = stream.read();
-    } while (null !== chunk && 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) {
+Readable.prototype.wrap = function (stream) {
   var state = this._readableState;
   var paused = false;
 
   var self = this;
-  stream.on('end', function() {
+  stream.on('end', function () {
     debug('wrapped end');
     if (state.decoder && !state.ended) {
       var chunk = state.decoder.end();
-      if (chunk && chunk.length)
-        self.push(chunk);
+      if (chunk && chunk.length) self.push(chunk);
     }
 
     self.push(null);
   });
 
-  stream.on('data', function(chunk) {
+  stream.on('data', function (chunk) {
     debug('wrapped data');
-    if (state.decoder)
-      chunk = state.decoder.write(chunk);
-    if (!chunk || !state.objectMode && !chunk.length)
-      return;
+    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) {
@@ -819,22 +770,24 @@ Readable.prototype.wrap = function(stream) {
   // proxy all the other methods.
   // important when wrapping filters and duplexes.
   for (var i in stream) {
-    if (util.isFunction(stream[i]) && util.isUndefined(this[i])) {
-      this[i] = function(method) { return function() {
-        return stream[method].apply(stream, arguments);
-      }}(i);
+    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.
   var events = ['error', 'close', 'destroy', 'pause', 'resume'];
-  forEach(events, function(ev) {
+  forEach(events, function (ev) {
     stream.on(ev, self.emit.bind(self, ev));
   });
 
   // when we try to consume some more bytes, simply unpause the
   // underlying stream.
-  self._read = function(n) {
+  self._read = function (n) {
     debug('wrapped _read', n);
     if (paused) {
       paused = false;
@@ -845,74 +798,106 @@ Readable.prototype.wrap = function(stream) {
   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) {
-  var list = state.buffer;
-  var length = state.length;
-  var stringMode = !!state.decoder;
-  var objectMode = !!state.objectMode;
+  // 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);
+  }
 
-  // nothing in the list, definitely empty.
-  if (list.length === 0)
-    return null;
+  return ret;
+}
 
-  if (length === 0)
-    ret = null;
-  else if (objectMode)
+// 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 if (!n || n >= length) {
-    // read it all, truncate the array.
-    if (stringMode)
-      ret = list.join('');
-    else
-      ret = Buffer.concat(list, length);
-    list.length = 0;
   } else {
-    // read just some of it.
-    if (n < list[0].length) {
-      // just take a part of the first list item.
-      // slice is the same for buffers and strings.
-      var buf = list[0];
-      ret = buf.slice(0, n);
-      list[0] = buf.slice(n);
-    } else if (n === list[0].length) {
-      // first list is a perfect match
-      ret = list.shift();
-    } else {
-      // complex case.
-      // we have enough to cover it, but it spans past the first buffer.
-      if (stringMode)
-        ret = '';
-      else
-        ret = new Buffer(n);
-
-      var c = 0;
-      for (var i = 0, l = list.length; i < l && c < n; i++) {
-        var buf = list[0];
-        var cpy = Math.min(n - c, buf.length);
-
-        if (stringMode)
-          ret += buf.slice(0, cpy);
-        else
-          buf.copy(ret, c, 0, cpy);
-
-        if (cpy < buf.length)
-          list[0] = buf.slice(cpy);
-        else
-          list.shift();
-
-        c += cpy;
+    // 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 = bufferShim.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;
 }
 
@@ -921,31 +906,32 @@ function endReadable(stream) {
 
   // 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.length > 0) throw new Error('"endReadable()" called on non-empty stream');
 
   if (!state.endEmitted) {
     state.ended = true;
-    process.nextTick(function() {
-      // Check that we didn't get one last unshift.
-      if (!state.endEmitted && state.length === 0) {
-        state.endEmitted = true;
-        stream.readable = false;
-        stream.emit('end');
-      }
-    });
+    processNextTick(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 forEach (xs, f) {
+function forEach(xs, f) {
   for (var i = 0, l = xs.length; i < l; i++) {
     f(xs[i], i);
   }
 }
 
-function indexOf (xs, x) {
+function indexOf(xs, x) {
   for (var i = 0, l = xs.length; i < l; i++) {
     if (xs[i] === x) return i;
   }
   return -1;
-}
+}
\ No newline at end of file