add node_modules to address #4364

5 files changed, 1772 insertions, 0 deletions

diff --git a/node_modules/readable-stream/lib/_stream_duplex.js b/node_modules/readable-stream/lib/_stream_duplex.js
new file mode 100644
index 000000000..b513d61a9
--- /dev/null
+++ b/node_modules/readable-stream/lib/_stream_duplex.js
@@ -0,0 +1,89 @@
+// 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.
+
+// a duplex stream is just a stream that is both readable and writable.
+// Since JS doesn't have multiple prototypal inheritance, this class
+// prototypally inherits from Readable, and then parasitically from
+// Writable.
+
+module.exports = Duplex;
+
+/*<replacement>*/
+var objectKeys = Object.keys || function (obj) {
+  var keys = [];
+  for (var key in obj) keys.push(key);
+  return keys;
+}
+/*</replacement>*/
+
+
+/*<replacement>*/
+var util = require('core-util-is');
+util.inherits = require('inherits');
+/*</replacement>*/
+
+var Readable = require('./_stream_readable');
+var Writable = require('./_stream_writable');
+
+util.inherits(Duplex, Readable);
+
+forEach(objectKeys(Writable.prototype), function(method) {
+  if (!Duplex.prototype[method])
+    Duplex.prototype[method] = Writable.prototype[method];
+});
+
+function Duplex(options) {
+  if (!(this instanceof Duplex))
+    return new Duplex(options);
+
+  Readable.call(this, options);
+  Writable.call(this, options);
+
+  if (options && options.readable === false)
+    this.readable = false;
+
+  if (options && options.writable === false)
+    this.writable = false;
+
+  this.allowHalfOpen = true;
+  if (options && options.allowHalfOpen === false)
+    this.allowHalfOpen = false;
+
+  this.once('end', onend);
+}
+
+// the no-half-open enforcer
+function onend() {
+  // if we allow half-open state, or if the writable side ended,
+  // then we're ok.
+  if (this.allowHalfOpen || this._writableState.ended)
+    return;
+
+  // no more data can be written.
+  // But allow more writes to happen in this tick.
+  process.nextTick(this.end.bind(this));
+}
+
+function forEach (xs, f) {
+  for (var i = 0, l = xs.length; i < l; i++) {
+    f(xs[i], i);
+  }
+}
diff --git a/node_modules/readable-stream/lib/_stream_passthrough.js b/node_modules/readable-stream/lib/_stream_passthrough.js
new file mode 100644
index 000000000..895ca50a1
--- /dev/null
+++ b/node_modules/readable-stream/lib/_stream_passthrough.js
@@ -0,0 +1,46 @@
+// 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.
+
+// a passthrough stream.
+// basically just the most minimal sort of Transform stream.
+// Every written chunk gets output as-is.
+
+module.exports = PassThrough;
+
+var Transform = require('./_stream_transform');
+
+/*<replacement>*/
+var util = require('core-util-is');
+util.inherits = require('inherits');
+/*</replacement>*/
+
+util.inherits(PassThrough, Transform);
+
+function PassThrough(options) {
+  if (!(this instanceof PassThrough))
+    return new PassThrough(options);
+
+  Transform.call(this, options);
+}
+
+PassThrough.prototype._transform = function(chunk, encoding, cb) {
+  cb(null, chunk);
+};
diff --git a/node_modules/readable-stream/lib/_stream_readable.js b/node_modules/readable-stream/lib/_stream_readable.js
new file mode 100644
index 000000000..19ab35889
--- /dev/null
+++ b/node_modules/readable-stream/lib/_stream_readable.js
@@ -0,0 +1,951 @@
+// 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.
+
+module.exports = Readable;
+
+/*<replacement>*/
+var isArray = require('isarray');
+/*</replacement>*/
+
+
+/*<replacement>*/
+var Buffer = require('buffer').Buffer;
+/*</replacement>*/
+
+Readable.ReadableState = ReadableState;
+
+var EE = require('events').EventEmitter;
+
+/*<replacement>*/
+if (!EE.listenerCount) EE.listenerCount = function(emitter, type) {
+  return emitter.listeners(type).length;
+};
+/*</replacement>*/
+
+var Stream = require('stream');
+
+/*<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');
+} else {
+  debug = function () {};
+}
+/*</replacement>*/
+
+
+util.inherits(Readable, Stream);
+
+function ReadableState(options, stream) {
+  var Duplex = require('./_stream_duplex');
+
+  options = options || {};
+
+  // 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;
+
+  // cast to ints.
+  this.highWaterMark = ~~this.highWaterMark;
+
+  this.buffer = [];
+  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 onwrite cb is called 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 write 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;
+
+
+  // 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;
+
+  // 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';
+
+  // when piping, we only care about 'readable' events that happen
+  // after read()ing all the bytes and not getting any pushback.
+  this.ranOut = false;
+
+  // 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) {
+  var Duplex = require('./_stream_duplex');
+
+  if (!(this instanceof Readable))
+    return new Readable(options);
+
+  this._readableState = new ReadableState(options, this);
+
+  // legacy
+  this.readable = true;
+
+  Stream.call(this);
+}
+
+// Manually shove something into the read() buffer.
+// This returns true if the highWaterMark has not been hit yet,
+// similar to how Writable.write() returns true if you should
+// write() some more.
+Readable.prototype.push = function(chunk, encoding) {
+  var state = this._readableState;
+
+  if (util.isString(chunk) && !state.objectMode) {
+    encoding = encoding || state.defaultEncoding;
+    if (encoding !== state.encoding) {
+      chunk = new Buffer(chunk, encoding);
+      encoding = '';
+    }
+  }
+
+  return readableAddChunk(this, state, chunk, encoding, false);
+};
+
+// Unshift should *always* be something directly out of read()
+Readable.prototype.unshift = function(chunk) {
+  var state = this._readableState;
+  return readableAddChunk(this, state, chunk, '', true);
+};
+
+function readableAddChunk(stream, state, chunk, encoding, addToFront) {
+  var er = chunkInvalid(state, chunk);
+  if (er) {
+    stream.emit('error', er);
+  } else if (util.isNullOrUndefined(chunk)) {
+    state.reading = false;
+    if (!state.ended)
+      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);
+    } else {
+      if (state.decoder && !addToFront && !encoding)
+        chunk = state.decoder.write(chunk);
+
+      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);
+      }
+
+      maybeReadMore(stream, state);
+    }
+  } else if (!addToFront) {
+    state.reading = false;
+  }
+
+  return needMoreData(state);
+}
+
+
+
+// if it's past the high water mark, we can push in some more.
+// Also, if we have no data yet, we can stand some
+// more bytes.  This is to work around cases where hwm=0,
+// such as the repl.  Also, if the push() triggered a
+// readable event, and the user called read(largeNumber) such that
+// needReadable was set, then we ought to push more, so that another
+// 'readable' event will be triggered.
+function needMoreData(state) {
+  return !state.ended &&
+         (state.needReadable ||
+          state.length < state.highWaterMark ||
+          state.length === 0);
+}
+
+// backwards compatibility.
+Readable.prototype.setEncoding = function(enc) {
+  if (!StringDecoder)
+    StringDecoder = require('string_decoder/').StringDecoder;
+  this._readableState.decoder = new StringDecoder(enc);
+  this._readableState.encoding = enc;
+  return this;
+};
+
+// Don't raise the hwm > 128MB
+var MAX_HWM = 0x800000;
+function roundUpToNextPowerOf2(n) {
+  if (n >= MAX_HWM) {
+    n = MAX_HWM;
+  } else {
+    // Get the next highest power of 2
+    n--;
+    for (var p = 1; p < 32; p <<= 1) n |= n >> p;
+    n++;
+  }
+  return n;
+}
+
+function howMuchToRead(n, state) {
+  if (state.length === 0 && state.ended)
+    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;
+}
+
+// you can override either this method, or the async _read(n) below.
+Readable.prototype.read = function(n) {
+  debug('read', n);
+  var state = this._readableState;
+  var nOrig = n;
+
+  if (!util.isNumber(n) || n > 0)
+    state.emittedReadable = false;
+
+  // if we're doing read(0) to trigger a readable event, but we
+  // already have a bunch of data in the buffer, then just trigger
+  // the 'readable' event and move on.
+  if (n === 0 &&
+      state.needReadable &&
+      (state.length >= state.highWaterMark || state.ended)) {
+    debug('read: emitReadable', state.length, state.ended);
+    if (state.length === 0 && state.ended)
+      endReadable(this);
+    else
+      emitReadable(this);
+    return null;
+  }
+
+  n = howMuchToRead(n, state);
+
+  // if we've ended, and we're now clear, then finish it up.
+  if (n === 0 && state.ended) {
+    if (state.length === 0)
+      endReadable(this);
+    return null;
+  }
+
+  // All the actual chunk generation logic needs to be
+  // *below* the call to _read.  The reason is that in certain
+  // synthetic stream cases, such as passthrough streams, _read
+  // may be a completely synchronous operation which may change
+  // the state of the read buffer, providing enough data when
+  // before there was *not* enough.
+  //
+  // So, the steps are:
+  // 1. Figure out what the state of things will be after we do
+  // a read from the buffer.
+  //
+  // 2. If that resulting state will trigger a _read, then call _read.
+  // Note that this may be asynchronous, or synchronous.  Yes, it is
+  // deeply ugly to write APIs this way, but that still doesn't mean
+  // that the Readable class should behave improperly, as streams are
+  // designed to be sync/async agnostic.
+  // Take note if the _read call is sync or async (ie, if the read call
+  // has returned yet), so that we know whether or not it's safe to emit
+  // 'readable' etc.
+  //
+  // 3. Actually pull the requested chunks out of the buffer and return.
+
+  // if we need a readable event, then we need to do some reading.
+  var doRead = state.needReadable;
+  debug('need readable', doRead);
+
+  // if we currently have less than the highWaterMark, then also read some
+  if (state.length === 0 || state.length - n < state.highWaterMark) {
+    doRead = true;
+    debug('length less than watermark', doRead);
+  }
+
+  // however, if we've ended, then there's no point, and if we're already
+  // reading, then it's unnecessary.
+  if (state.ended || state.reading) {
+    doRead = false;
+    debug('reading or ended', doRead);
+  }
+
+  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 (doRead && !state.reading)
+    n = howMuchToRead(nOrig, state);
+
+  var ret;
+  if (n > 0)
+    ret = fromList(n, state);
+  else
+    ret = null;
+
+  if (util.isNull(ret)) {
+    state.needReadable = true;
+    n = 0;
+  }
+
+  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 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 (!util.isNull(ret))
+    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) {
+    er = new TypeError('Invalid non-string/buffer chunk');
+  }
+  return er;
+}
+
+
+function onEofChunk(stream, state) {
+  if (state.decoder && !state.ended) {
+    var chunk = state.decoder.end();
+    if (chunk && chunk.length) {
+      state.buffer.push(chunk);
+      state.length += state.objectMode ? 1 : chunk.length;
+    }
+  }
+  state.ended = true;
+
+  // emit 'readable' now to make sure it gets picked up.
+  emitReadable(stream);
+}
+
+// Don't emit readable right away in sync mode, because this can trigger
+// another read() call => stack overflow.  This way, it might trigger
+// a nextTick recursion warning, but that's not so bad.
+function emitReadable(stream) {
+  var state = stream._readableState;
+  state.needReadable = false;
+  if (!state.emittedReadable) {
+    debug('emitReadable', state.flowing);
+    state.emittedReadable = true;
+    if (state.sync)
+      process.nextTick(function() {
+        emitReadable_(stream);
+      });
+    else
+      emitReadable_(stream);
+  }
+}
+
+function emitReadable_(stream) {
+  debug('emit readable');
+  stream.emit('readable');
+  flow(stream);
+}
+
+
+// at this point, the user has presumably seen the 'readable' event,
+// and called read() to consume some data.  that may have triggered
+// in turn another _read(n) call, in which case reading = true if
+// it's in progress.
+// However, if we're not ended, or reading, and the length < hwm,
+// then go ahead and try to read some more preemptively.
+function maybeReadMore(stream, state) {
+  if (!state.readingMore) {
+    state.readingMore = true;
+    process.nextTick(function() {
+      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('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 : cleanup;
+  if (state.endEmitted)
+    process.nextTick(endFn);
+  else
+    src.once('end', endFn);
+
+  dest.on('unpipe', onunpipe);
+  function onunpipe(readable) {
+    debug('onunpipe');
+    if (readable === src) {
+      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);
+
+  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', cleanup);
+    src.removeListener('data', ondata);
+
+    // 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);
+    if (false === ret) {
+      debug('false write response, pause',
+            src._readableState.awaitDrain);
+      src._readableState.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 (EE.listenerCount(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];
+
+
+
+  // Both close and finish should trigger unpipe, but only once.
+  function onclose() {
+    dest.removeListener('finish', onfinish);
+    unpipe();
+  }
+  dest.once('close', onclose);
+  function onfinish() {
+    debug('onfinish');
+    dest.removeListener('close', onclose);
+    unpipe();
+  }
+  dest.once('finish', onfinish);
+
+  function unpipe() {
+    debug('unpipe');
+    src.unpipe(dest);
+  }
+
+  // tell the dest that it's being piped to
+  dest.emit('pipe', src);
+
+  // start the flow if it hasn't been started already.
+  if (!state.flowing) {
+    debug('pipe resume');
+    src.resume();
+  }
+
+  return dest;
+};
+
+function pipeOnDrain(src) {
+  return function() {
+    var state = src._readableState;
+    debug('pipeOnDrain', state.awaitDrain);
+    if (state.awaitDrain)
+      state.awaitDrain--;
+    if (state.awaitDrain === 0 && EE.listenerCount(src, 'data')) {
+      state.flowing = true;
+      flow(src);
+    }
+  };
+}
+
+
+Readable.prototype.unpipe = function(dest) {
+  var state = this._readableState;
+
+  // 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);
+    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);
+    return this;
+  }
+
+  // try to find the right one.
+  var i = indexOf(state.pipes, dest);
+  if (i === -1)
+    return this;
+
+  state.pipes.splice(i, 1);
+  state.pipesCount -= 1;
+  if (state.pipesCount === 1)
+    state.pipes = state.pipes[0];
+
+  dest.emit('unpipe', this);
+
+  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 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) {
+    var state = this._readableState;
+    if (!state.readableListening) {
+      state.readableListening = true;
+      state.emittedReadable = false;
+      state.needReadable = true;
+      if (!state.reading) {
+        var self = this;
+        process.nextTick(function() {
+          debug('readable nexttick read 0');
+          self.read(0);
+        });
+      } else if (state.length) {
+        emitReadable(this, state);
+      }
+    }
+  }
+
+  return res;
+};
+Readable.prototype.addListener = Readable.prototype.on;
+
+// 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;
+    if (!state.reading) {
+      debug('resume read 0');
+      this.read(0);
+    }
+    resume(this, state);
+  }
+  return this;
+};
+
+function resume(stream, state) {
+  if (!state.resumeScheduled) {
+    state.resumeScheduled = true;
+    process.nextTick(function() {
+      resume_(stream, state);
+    });
+  }
+}
+
+function resume_(stream, state) {
+  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 (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);
+  if (state.flowing) {
+    do {
+      var chunk = stream.read();
+    } while (null !== chunk && state.flowing);
+  }
+}
+
+// wrap an old-style stream as the async data source.
+// This is *not* part of the readable stream interface.
+// It is an ugly unfortunate mess of history.
+Readable.prototype.wrap = function(stream) {
+  var state = this._readableState;
+  var paused = false;
+
+  var self = this;
+  stream.on('end', function() {
+    debug('wrapped end');
+    if (state.decoder && !state.ended) {
+      var chunk = state.decoder.end();
+      if (chunk && chunk.length)
+        self.push(chunk);
+    }
+
+    self.push(null);
+  });
+
+  stream.on('data', function(chunk) {
+    debug('wrapped data');
+    if (state.decoder)
+      chunk = state.decoder.write(chunk);
+    if (!chunk || !state.objectMode && !chunk.length)
+      return;
+
+    var ret = self.push(chunk);
+    if (!ret) {
+      paused = true;
+      stream.pause();
+    }
+  });
+
+  // proxy all the other methods.
+  // important when wrapping filters and duplexes.
+  for (var i in stream) {
+    if (util.isFunction(stream[i]) && util.isUndefined(this[i])) {
+      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) {
+    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) {
+    debug('wrapped _read', n);
+    if (paused) {
+      paused = false;
+      stream.resume();
+    }
+  };
+
+  return self;
+};
+
+
+
+// exposed for testing purposes only.
+Readable._fromList = fromList;
+
+// Pluck off n bytes from an array of buffers.
+// Length is the combined lengths of all the buffers in the list.
+function fromList(n, state) {
+  var list = state.buffer;
+  var length = state.length;
+  var stringMode = !!state.decoder;
+  var objectMode = !!state.objectMode;
+  var ret;
+
+  // nothing in the list, definitely empty.
+  if (list.length === 0)
+    return null;
+
+  if (length === 0)
+    ret = null;
+  else if (objectMode)
+    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;
+      }
+    }
+  }
+
+  return ret;
+}
+
+function endReadable(stream) {
+  var state = stream._readableState;
+
+  // If we get here before consuming all the bytes, then that is a
+  // bug in node.  Should never happen.
+  if (state.length > 0)
+    throw new Error('endReadable called on non-empty stream');
+
+  if (!state.endEmitted) {
+    state.ended = true;
+    process.nextTick(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');
+      }
+    });
+  }
+}
+
+function forEach (xs, f) {
+  for (var i = 0, l = xs.length; i < l; i++) {
+    f(xs[i], i);
+  }
+}
+
+function indexOf (xs, x) {
+  for (var i = 0, l = xs.length; i < l; i++) {
+    if (xs[i] === x) return i;
+  }
+  return -1;
+}
diff --git a/node_modules/readable-stream/lib/_stream_transform.js b/node_modules/readable-stream/lib/_stream_transform.js
new file mode 100644
index 000000000..905c5e450
--- /dev/null
+++ b/node_modules/readable-stream/lib/_stream_transform.js
@@ -0,0 +1,209 @@
+// 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.
+
+
+// a transform stream is a readable/writable stream where you do
+// something with the data.  Sometimes it's called a "filter",
+// but that's not a great name for it, since that implies a thing where
+// some bits pass through, and others are simply ignored.  (That would
+// be a valid example of a transform, of course.)
+//
+// While the output is causally related to the input, it's not a
+// necessarily symmetric or synchronous transformation.  For example,
+// a zlib stream might take multiple plain-text writes(), and then
+// emit a single compressed chunk some time in the future.
+//
+// Here's how this works:
+//
+// The Transform stream has all the aspects of the readable and writable
+// stream classes.  When you write(chunk), that calls _write(chunk,cb)
+// internally, and returns false if there's a lot of pending writes
+// buffered up.  When you call read(), that calls _read(n) until
+// there's enough pending readable data buffered up.
+//
+// In a transform stream, the written data is placed in a buffer.  When
+// _read(n) is called, it transforms the queued up data, calling the
+// buffered _write cb's as it consumes chunks.  If consuming a single
+// written chunk would result in multiple output chunks, then the first
+// outputted bit calls the readcb, and subsequent chunks just go into
+// the read buffer, and will cause it to emit 'readable' if necessary.
+//
+// This way, back-pressure is actually determined by the reading side,
+// since _read has to be called to start processing a new chunk.  However,
+// a pathological inflate type of transform can cause excessive buffering
+// here.  For example, imagine a stream where every byte of input is
+// interpreted as an integer from 0-255, and then results in that many
+// bytes of output.  Writing the 4 bytes {ff,ff,ff,ff} would result in
+// 1kb of data being output.  In this case, you could write a very small
+// amount of input, and end up with a very large amount of output.  In
+// such a pathological inflating mechanism, there'd be no way to tell
+// the system to stop doing the transform.  A single 4MB write could
+// cause the system to run out of memory.
+//
+// However, even in such a pathological case, only a single written chunk
+// would be consumed, and then the rest would wait (un-transformed) until
+// the results of the previous transformed chunk were consumed.
+
+module.exports = Transform;
+
+var Duplex = require('./_stream_duplex');
+
+/*<replacement>*/
+var util = require('core-util-is');
+util.inherits = require('inherits');
+/*</replacement>*/
+
+util.inherits(Transform, Duplex);
+
+
+function TransformState(options, stream) {
+  this.afterTransform = function(er, data) {
+    return afterTransform(stream, er, data);
+  };
+
+  this.needTransform = false;
+  this.transforming = false;
+  this.writecb = null;
+  this.writechunk = null;
+}
+
+function afterTransform(stream, er, data) {
+  var ts = stream._transformState;
+  ts.transforming = false;
+
+  var cb = ts.writecb;
+
+  if (!cb)
+    return stream.emit('error', new Error('no writecb in Transform class'));
+
+  ts.writechunk = null;
+  ts.writecb = null;
+
+  if (!util.isNullOrUndefined(data))
+    stream.push(data);
+
+  if (cb)
+    cb(er);
+
+  var rs = stream._readableState;
+  rs.reading = false;
+  if (rs.needReadable || rs.length < rs.highWaterMark) {
+    stream._read(rs.highWaterMark);
+  }
+}
+
+
+function Transform(options) {
+  if (!(this instanceof Transform))
+    return new Transform(options);
+
+  Duplex.call(this, options);
+
+  this._transformState = new TransformState(options, this);
+
+  // when the writable side finishes, then flush out anything remaining.
+  var stream = this;
+
+  // start out asking for a readable event once data is transformed.
+  this._readableState.needReadable = true;
+
+  // we have implemented the _read method, and done the other things
+  // that Readable wants before the first _read call, so unset the
+  // sync guard flag.
+  this._readableState.sync = false;
+
+  this.once('prefinish', function() {
+    if (util.isFunction(this._flush))
+      this._flush(function(er) {
+        done(stream, er);
+      });
+    else
+      done(stream);
+  });
+}
+
+Transform.prototype.push = function(chunk, encoding) {
+  this._transformState.needTransform = false;
+  return Duplex.prototype.push.call(this, chunk, encoding);
+};
+
+// This is the part where you do stuff!
+// override this function in implementation classes.
+// 'chunk' is an input chunk.
+//
+// Call `push(newChunk)` to pass along transformed output
+// to the readable side.  You may call 'push' zero or more times.
+//
+// Call `cb(err)` when you are done with this chunk.  If you pass
+// an error, then that'll put the hurt on the whole operation.  If you
+// never call cb(), then you'll never get another chunk.
+Transform.prototype._transform = function(chunk, encoding, cb) {
+  throw new Error('not implemented');
+};
+
+Transform.prototype._write = function(chunk, encoding, cb) {
+  var ts = this._transformState;
+  ts.writecb = cb;
+  ts.writechunk = chunk;
+  ts.writeencoding = encoding;
+  if (!ts.transforming) {
+    var rs = this._readableState;
+    if (ts.needTransform ||
+        rs.needReadable ||
+        rs.length < rs.highWaterMark)
+      this._read(rs.highWaterMark);
+  }
+};
+
+// Doesn't matter what the args are here.
+// _transform does all the work.
+// That we got here means that the readable side wants more data.
+Transform.prototype._read = function(n) {
+  var ts = this._transformState;
+
+  if (!util.isNull(ts.writechunk) && ts.writecb && !ts.transforming) {
+    ts.transforming = true;
+    this._transform(ts.writechunk, ts.writeencoding, ts.afterTransform);
+  } else {
+    // mark that we need a transform, so that any data that comes in
+    // will get processed, now that we've asked for it.
+    ts.needTransform = true;
+  }
+};
+
+
+function done(stream, er) {
+  if (er)
+    return stream.emit('error', er);
+
+  // if there's nothing in the write buffer, then that means
+  // that nothing more will ever be provided
+  var ws = stream._writableState;
+  var ts = stream._transformState;
+
+  if (ws.length)
+    throw new Error('calling transform done when ws.length != 0');
+
+  if (ts.transforming)
+    throw new Error('calling transform done when still transforming');
+
+  return stream.push(null);
+}
diff --git a/node_modules/readable-stream/lib/_stream_writable.js b/node_modules/readable-stream/lib/_stream_writable.js
new file mode 100644
index 000000000..db8539cd5
--- /dev/null
+++ b/node_modules/readable-stream/lib/_stream_writable.js
@@ -0,0 +1,477 @@
+// 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.
+
+// A bit simpler than readable streams.
+// Implement an async ._write(chunk, cb), and it'll handle all
+// the drain event emission and buffering.
+
+module.exports = Writable;
+
+/*<replacement>*/
+var Buffer = require('buffer').Buffer;
+/*</replacement>*/
+
+Writable.WritableState = WritableState;
+
+
+/*<replacement>*/
+var util = require('core-util-is');
+util.inherits = require('inherits');
+/*</replacement>*/
+
+var Stream = require('stream');
+
+util.inherits(Writable, Stream);
+
+function WriteReq(chunk, encoding, cb) {
+  this.chunk = chunk;
+  this.encoding = encoding;
+  this.callback = cb;
+}
+
+function WritableState(options, stream) {
+  var Duplex = require('./_stream_duplex');
+
+  options = options || {};
+
+  // the point at which write() starts returning false
+  // Note: 0 is a valid value, means that we always return false if
+  // the entire buffer is not flushed immediately on write()
+  var hwm = options.highWaterMark;
+  var defaultHwm = options.objectMode ? 16 : 16 * 1024;
+  this.highWaterMark = (hwm || hwm === 0) ? hwm : defaultHwm;
+
+  // object stream flag to indicate whether or not this stream
+  // contains buffers or objects.
+  this.objectMode = !!options.objectMode;
+
+  if (stream instanceof Duplex)
+    this.objectMode = this.objectMode || !!options.writableObjectMode;
+
+  // cast to ints.
+  this.highWaterMark = ~~this.highWaterMark;
+
+  this.needDrain = false;
+  // at the start of calling end()
+  this.ending = false;
+  // when end() has been called, and returned
+  this.ended = false;
+  // when 'finish' is emitted
+  this.finished = false;
+
+  // should we decode strings into buffers before passing to _write?
+  // this is here so that some node-core streams can optimize string
+  // handling at a lower level.
+  var noDecode = options.decodeStrings === false;
+  this.decodeStrings = !noDecode;
+
+  // 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';
+
+  // not an actual buffer we keep track of, but a measurement
+  // of how much we're waiting to get pushed to some underlying
+  // socket or file.
+  this.length = 0;
+
+  // a flag to see when we're in the middle of a write.
+  this.writing = false;
+
+  // when true all writes will be buffered until .uncork() call
+  this.corked = 0;
+
+  // a flag to be able to tell if the onwrite cb is called 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 write call.
+  this.sync = true;
+
+  // a flag to know if we're processing previously buffered items, which
+  // may call the _write() callback in the same tick, so that we don't
+  // end up in an overlapped onwrite situation.
+  this.bufferProcessing = false;
+
+  // the callback that's passed to _write(chunk,cb)
+  this.onwrite = function(er) {
+    onwrite(stream, er);
+  };
+
+  // the callback that the user supplies to write(chunk,encoding,cb)
+  this.writecb = null;
+
+  // the amount that is being written when _write is called.
+  this.writelen = 0;
+
+  this.buffer = [];
+
+  // number of pending user-supplied write callbacks
+  // this must be 0 before 'finish' can be emitted
+  this.pendingcb = 0;
+
+  // emit prefinish if the only thing we're waiting for is _write cbs
+  // This is relevant for synchronous Transform streams
+  this.prefinished = false;
+
+  // True if the error was already emitted and should not be thrown again
+  this.errorEmitted = false;
+}
+
+function Writable(options) {
+  var Duplex = require('./_stream_duplex');
+
+  // Writable ctor is applied to Duplexes, though they're not
+  // instanceof Writable, they're instanceof Readable.
+  if (!(this instanceof Writable) && !(this instanceof Duplex))
+    return new Writable(options);
+
+  this._writableState = new WritableState(options, this);
+
+  // legacy.
+  this.writable = true;
+
+  Stream.call(this);
+}
+
+// Otherwise people can pipe Writable streams, which is just wrong.
+Writable.prototype.pipe = function() {
+  this.emit('error', new Error('Cannot pipe. Not readable.'));
+};
+
+
+function writeAfterEnd(stream, state, cb) {
+  var er = new Error('write after end');
+  // TODO: defer error events consistently everywhere, not just the cb
+  stream.emit('error', er);
+  process.nextTick(function() {
+    cb(er);
+  });
+}
+
+// If we get something that is not a buffer, string, null, or undefined,
+// and we're not in objectMode, then that's an error.
+// Otherwise stream chunks are all considered to be of length=1, and the
+// watermarks determine how many objects to keep in the buffer, rather than
+// how many bytes or characters.
+function validChunk(stream, state, chunk, cb) {
+  var valid = true;
+  if (!util.isBuffer(chunk) &&
+      !util.isString(chunk) &&
+      !util.isNullOrUndefined(chunk) &&
+      !state.objectMode) {
+    var er = new TypeError('Invalid non-string/buffer chunk');
+    stream.emit('error', er);
+    process.nextTick(function() {
+      cb(er);
+    });
+    valid = false;
+  }
+  return valid;
+}
+
+Writable.prototype.write = function(chunk, encoding, cb) {
+  var state = this._writableState;
+  var ret = false;
+
+  if (util.isFunction(encoding)) {
+    cb = encoding;
+    encoding = null;
+  }
+
+  if (util.isBuffer(chunk))
+    encoding = 'buffer';
+  else if (!encoding)
+    encoding = state.defaultEncoding;
+
+  if (!util.isFunction(cb))
+    cb = function() {};
+
+  if (state.ended)
+    writeAfterEnd(this, state, cb);
+  else if (validChunk(this, state, chunk, cb)) {
+    state.pendingcb++;
+    ret = writeOrBuffer(this, state, chunk, encoding, cb);
+  }
+
+  return ret;
+};
+
+Writable.prototype.cork = function() {
+  var state = this._writableState;
+
+  state.corked++;
+};
+
+Writable.prototype.uncork = function() {
+  var state = this._writableState;
+
+  if (state.corked) {
+    state.corked--;
+
+    if (!state.writing &&
+        !state.corked &&
+        !state.finished &&
+        !state.bufferProcessing &&
+        state.buffer.length)
+      clearBuffer(this, state);
+  }
+};
+
+function decodeChunk(state, chunk, encoding) {
+  if (!state.objectMode &&
+      state.decodeStrings !== false &&
+      util.isString(chunk)) {
+    chunk = new Buffer(chunk, encoding);
+  }
+  return chunk;
+}
+
+// if we're already writing something, then just put this
+// in the queue, and wait our turn.  Otherwise, call _write
+// If we return false, then we need a drain event, so set that flag.
+function writeOrBuffer(stream, state, chunk, encoding, cb) {
+  chunk = decodeChunk(state, chunk, encoding);
+  if (util.isBuffer(chunk))
+    encoding = 'buffer';
+  var len = state.objectMode ? 1 : chunk.length;
+
+  state.length += len;
+
+  var ret = state.length < state.highWaterMark;
+  // we must ensure that previous needDrain will not be reset to false.
+  if (!ret)
+    state.needDrain = true;
+
+  if (state.writing || state.corked)
+    state.buffer.push(new WriteReq(chunk, encoding, cb));
+  else
+    doWrite(stream, state, false, len, chunk, encoding, cb);
+
+  return ret;
+}
+
+function doWrite(stream, state, writev, len, chunk, encoding, cb) {
+  state.writelen = len;
+  state.writecb = cb;
+  state.writing = true;
+  state.sync = true;
+  if (writev)
+    stream._writev(chunk, state.onwrite);
+  else
+    stream._write(chunk, encoding, state.onwrite);
+  state.sync = false;
+}
+
+function onwriteError(stream, state, sync, er, cb) {
+  if (sync)
+    process.nextTick(function() {
+      state.pendingcb--;
+      cb(er);
+    });
+  else {
+    state.pendingcb--;
+    cb(er);
+  }
+
+  stream._writableState.errorEmitted = true;
+  stream.emit('error', er);
+}
+
+function onwriteStateUpdate(state) {
+  state.writing = false;
+  state.writecb = null;
+  state.length -= state.writelen;
+  state.writelen = 0;
+}
+
+function onwrite(stream, er) {
+  var state = stream._writableState;
+  var sync = state.sync;
+  var cb = state.writecb;
+
+  onwriteStateUpdate(state);
+
+  if (er)
+    onwriteError(stream, state, sync, er, cb);
+  else {
+    // Check if we're actually ready to finish, but don't emit yet
+    var finished = needFinish(stream, state);
+
+    if (!finished &&
+        !state.corked &&
+        !state.bufferProcessing &&
+        state.buffer.length) {
+      clearBuffer(stream, state);
+    }
+
+    if (sync) {
+      process.nextTick(function() {
+        afterWrite(stream, state, finished, cb);
+      });
+    } else {
+      afterWrite(stream, state, finished, cb);
+    }
+  }
+}
+
+function afterWrite(stream, state, finished, cb) {
+  if (!finished)
+    onwriteDrain(stream, state);
+  state.pendingcb--;
+  cb();
+  finishMaybe(stream, state);
+}
+
+// Must force callback to be called on nextTick, so that we don't
+// emit 'drain' before the write() consumer gets the 'false' return
+// value, and has a chance to attach a 'drain' listener.
+function onwriteDrain(stream, state) {
+  if (state.length === 0 && state.needDrain) {
+    state.needDrain = false;
+    stream.emit('drain');
+  }
+}
+
+
+// if there's something in the buffer waiting, then process it
+function clearBuffer(stream, state) {
+  state.bufferProcessing = true;
+
+  if (stream._writev && state.buffer.length > 1) {
+    // Fast case, write everything using _writev()
+    var cbs = [];
+    for (var c = 0; c < state.buffer.length; c++)
+      cbs.push(state.buffer[c].callback);
+
+    // count the one we are adding, as well.
+    // TODO(isaacs) clean this up
+    state.pendingcb++;
+    doWrite(stream, state, true, state.length, state.buffer, '', function(err) {
+      for (var i = 0; i < cbs.length; i++) {
+        state.pendingcb--;
+        cbs[i](err);
+      }
+    });
+
+    // Clear buffer
+    state.buffer = [];
+  } else {
+    // Slow case, write chunks one-by-one
+    for (var c = 0; c < state.buffer.length; c++) {
+      var entry = state.buffer[c];
+      var chunk = entry.chunk;
+      var encoding = entry.encoding;
+      var cb = entry.callback;
+      var len = state.objectMode ? 1 : chunk.length;
+
+      doWrite(stream, state, false, len, chunk, encoding, cb);
+
+      // if we didn't call the onwrite immediately, then
+      // it means that we need to wait until it does.
+      // also, that means that the chunk and cb are currently
+      // being processed, so move the buffer counter past them.
+      if (state.writing) {
+        c++;
+        break;
+      }
+    }
+
+    if (c < state.buffer.length)
+      state.buffer = state.buffer.slice(c);
+    else
+      state.buffer.length = 0;
+  }
+
+  state.bufferProcessing = false;
+}
+
+Writable.prototype._write = function(chunk, encoding, cb) {
+  cb(new Error('not implemented'));
+
+};
+
+Writable.prototype._writev = null;
+
+Writable.prototype.end = function(chunk, encoding, cb) {
+  var state = this._writableState;
+
+  if (util.isFunction(chunk)) {
+    cb = chunk;
+    chunk = null;
+    encoding = null;
+  } else if (util.isFunction(encoding)) {
+    cb = encoding;
+    encoding = null;
+  }
+
+  if (!util.isNullOrUndefined(chunk))
+    this.write(chunk, encoding);
+
+  // .end() fully uncorks
+  if (state.corked) {
+    state.corked = 1;
+    this.uncork();
+  }
+
+  // ignore unnecessary end() calls.
+  if (!state.ending && !state.finished)
+    endWritable(this, state, cb);
+};
+
+
+function needFinish(stream, state) {
+  return (state.ending &&
+          state.length === 0 &&
+          !state.finished &&
+          !state.writing);
+}
+
+function prefinish(stream, state) {
+  if (!state.prefinished) {
+    state.prefinished = true;
+    stream.emit('prefinish');
+  }
+}
+
+function finishMaybe(stream, state) {
+  var need = needFinish(stream, state);
+  if (need) {
+    if (state.pendingcb === 0) {
+      prefinish(stream, state);
+      state.finished = true;
+      stream.emit('finish');
+    } else
+      prefinish(stream, state);
+  }
+  return need;
+}
+
+function endWritable(stream, state, cb) {
+  state.ending = true;
+  finishMaybe(stream, state);
+  if (cb) {
+    if (state.finished)
+      process.nextTick(cb);
+    else
+      stream.once('finish', cb);
+  }
+  state.ended = true;
+}