upgrade dependencies

2 files changed, 532 insertions, 296 deletions

diff --git a/node_modules/browserify-zlib/src/binding.js b/node_modules/browserify-zlib/src/binding.js
index 7244b4384..14e419d2e 100644
--- a/node_modules/browserify-zlib/src/binding.js
+++ b/node_modules/browserify-zlib/src/binding.js
@@ -1,236 +1,432 @@
-var msg = require('pako/lib/zlib/messages');
-var zstream = require('pako/lib/zlib/zstream');
-var zlib_deflate = require('pako/lib/zlib/deflate.js');
-var zlib_inflate = require('pako/lib/zlib/inflate.js');
-var constants = require('pako/lib/zlib/constants');
+'use strict'
+/* eslint camelcase: "off" */
+
+var assert = require('assert')
+
+var Zstream = require('pako/lib/zlib/zstream')
+var zlib_deflate = require('pako/lib/zlib/deflate.js')
+var zlib_inflate = require('pako/lib/zlib/inflate.js')
+var constants = require('pako/lib/zlib/constants')
 
 for (var key in constants) {
-  exports[key] = constants[key];
+  exports[key] = constants[key]
 }
 
 // zlib modes
-exports.NONE = 0;
-exports.DEFLATE = 1;
-exports.INFLATE = 2;
-exports.GZIP = 3;
-exports.GUNZIP = 4;
-exports.DEFLATERAW = 5;
-exports.INFLATERAW = 6;
-exports.UNZIP = 7;
+exports.NONE = 0
+exports.DEFLATE = 1
+exports.INFLATE = 2
+exports.GZIP = 3
+exports.GUNZIP = 4
+exports.DEFLATERAW = 5
+exports.INFLATERAW = 6
+exports.UNZIP = 7
+
+var GZIP_HEADER_ID1 = 0x1f
+var GZIP_HEADER_ID2 = 0x8b
 
 /**
  * Emulate Node's zlib C++ layer for use by the JS layer in index.js
  */
-function Zlib(mode) {
-  if (mode < exports.DEFLATE || mode > exports.UNZIP)
-    throw new TypeError("Bad argument");
-    
-  this.mode = mode;
-  this.init_done = false;
-  this.write_in_progress = false;
-  this.pending_close = false;
-  this.windowBits = 0;
-  this.level = 0;
-  this.memLevel = 0;
-  this.strategy = 0;
-  this.dictionary = null;
-}
-
-Zlib.prototype.init = function(windowBits, level, memLevel, strategy, dictionary) {
-  this.windowBits = windowBits;
-  this.level = level;
-  this.memLevel = memLevel;
-  this.strategy = strategy;
-  // dictionary not supported.
-  
-  if (this.mode === exports.GZIP || this.mode === exports.GUNZIP)
-    this.windowBits += 16;
-    
-  if (this.mode === exports.UNZIP)
-    this.windowBits += 32;
-    
-  if (this.mode === exports.DEFLATERAW || this.mode === exports.INFLATERAW)
-    this.windowBits = -this.windowBits;
-    
-  this.strm = new zstream();
-  
+function Zlib (mode) {
+  if (typeof mode !== 'number' || mode < exports.DEFLATE || mode > exports.UNZIP) {
+    throw new TypeError('Bad argument')
+  }
+
+  this.dictionary = null
+  this.err = 0
+  this.flush = 0
+  this.init_done = false
+  this.level = 0
+  this.memLevel = 0
+  this.mode = mode
+  this.strategy = 0
+  this.windowBits = 0
+  this.write_in_progress = false
+  this.pending_close = false
+  this.gzip_id_bytes_read = 0
+}
+
+Zlib.prototype.close = function () {
+  if (this.write_in_progress) {
+    this.pending_close = true
+    return
+  }
+
+  this.pending_close = false
+
+  assert(this.init_done, 'close before init')
+  assert(this.mode <= exports.UNZIP)
+
+  if (this.mode === exports.DEFLATE || this.mode === exports.GZIP || this.mode === exports.DEFLATERAW) {
+    zlib_deflate.deflateEnd(this.strm)
+  } else if (this.mode === exports.INFLATE || this.mode === exports.GUNZIP ||
+      this.mode === exports.INFLATERAW || this.mode === exports.UNZIP) {
+    zlib_inflate.inflateEnd(this.strm)
+  }
+
+  this.mode = exports.NONE
+
+  this.dictionary = null
+}
+
+Zlib.prototype.write = function (flush, input, in_off, in_len, out, out_off, out_len) {
+  return this._write(true, flush, input, in_off, in_len, out, out_off, out_len)
+}
+
+Zlib.prototype.writeSync = function (flush, input, in_off, in_len, out, out_off, out_len) {
+  return this._write(false, flush, input, in_off, in_len, out, out_off, out_len)
+}
+
+Zlib.prototype._write = function (async, flush, input, in_off, in_len, out, out_off, out_len) {
+  assert.equal(arguments.length, 8)
+
+  assert(this.init_done, 'write before init')
+  assert(this.mode !== exports.NONE, 'already finalized')
+  assert.equal(false, this.write_in_progress, 'write already in progress')
+  assert.equal(false, this.pending_close, 'close is pending')
+
+  this.write_in_progress = true
+
+  assert.equal(false, flush === undefined, 'must provide flush value')
+
+  this.write_in_progress = true
+
+  if (flush !== exports.Z_NO_FLUSH &&
+    flush !== exports.Z_PARTIAL_FLUSH &&
+    flush !== exports.Z_SYNC_FLUSH &&
+    flush !== exports.Z_FULL_FLUSH &&
+    flush !== exports.Z_FINISH &&
+    flush !== exports.Z_BLOCK) {
+    throw new Error('Invalid flush value')
+  }
+
+  if (input == null) {
+    input = Buffer.alloc(0)
+    in_len = 0
+    in_off = 0
+  }
+
+  this.strm.avail_in = in_len
+  this.strm.input = input
+  this.strm.next_in = in_off
+  this.strm.avail_out = out_len
+  this.strm.output = out
+  this.strm.next_out = out_off
+  this.flush = flush
+
+  if (!async) {
+    // sync version
+    this._process()
+
+    if (this._checkError()) {
+      return this._afterSync()
+    }
+    return
+  }
+
+  // async version
+  var self = this
+  process.nextTick(function () {
+    self._process()
+    self._after()
+  })
+
+  return this
+}
+
+Zlib.prototype._afterSync = function () {
+  var avail_out = this.strm.avail_out
+  var avail_in = this.strm.avail_in
+
+  this.write_in_progress = false
+
+  return [avail_in, avail_out]
+}
+
+Zlib.prototype._process = function () {
+  var next_expected_header_byte = null
+
+  // If the avail_out is left at 0, then it means that it ran out
+  // of room.  If there was avail_out left over, then it means
+  // that all of the input was consumed.
   switch (this.mode) {
     case exports.DEFLATE:
     case exports.GZIP:
     case exports.DEFLATERAW:
-      var status = zlib_deflate.deflateInit2(
+      this.err = zlib_deflate.deflate(this.strm, this.flush)
+      break
+    case exports.UNZIP:
+      if (this.strm.avail_in > 0) {
+        next_expected_header_byte = this.strm.next_in
+      }
+
+      switch (this.gzip_id_bytes_read) {
+        case 0:
+          if (next_expected_header_byte === null) {
+            break
+          }
+
+          if (this.strm.input[next_expected_header_byte] === GZIP_HEADER_ID1) {
+            this.gzip_id_bytes_read = 1
+            next_expected_header_byte++
+
+            if (this.strm.avail_in === 1) {
+              // The only available byte was already read.
+              break
+            }
+          } else {
+            this.mode = exports.INFLATE
+            break
+          }
+
+          // fallthrough
+        case 1:
+          if (next_expected_header_byte === null) {
+            break
+          }
+
+          if (this.strm.input[next_expected_header_byte] === GZIP_HEADER_ID2) {
+            this.gzip_id_bytes_read = 2
+            this.mode = exports.GUNZIP
+          } else {
+            // There is no actual difference between INFLATE and INFLATERAW
+            // (after initialization).
+            this.mode = exports.INFLATE
+          }
+
+          break
+        default:
+          throw new Error('invalid number of gzip magic number bytes read')
+      }
+
+      // fallthrough
+    case exports.INFLATE:
+    case exports.GUNZIP:
+    case exports.INFLATERAW:
+      this.err = zlib_inflate.inflate(this.strm, this.flush)
+
+      // If data was encoded with dictionary
+      if (this.err === exports.Z_NEED_DICT && this.dictionary) {
+        // Load it
+        this.err = zlib_inflate.inflateSetDictionary(this.strm, this.dictionary)
+        if (this.err === exports.Z_OK) {
+          // And try to decode again
+          this.err = zlib_inflate.inflate(this.strm, this.flush)
+        } else if (this.err === exports.Z_DATA_ERROR) {
+          // Both inflateSetDictionary() and inflate() return Z_DATA_ERROR.
+          // Make it possible for After() to tell a bad dictionary from bad
+          // input.
+          this.err = exports.Z_NEED_DICT
+        }
+      }
+      while (this.strm.avail_in > 0 &&
+             this.mode === exports.GUNZIP &&
+             this.err === exports.Z_STREAM_END &&
+             this.strm.next_in[0] !== 0x00) {
+        // Bytes remain in input buffer. Perhaps this is another compressed
+        // member in the same archive, or just trailing garbage.
+        // Trailing zero bytes are okay, though, since they are frequently
+        // used for padding.
+
+        this.reset()
+        this.err = zlib_inflate.inflate(this.strm, this.flush)
+      }
+      break
+    default:
+      throw new Error('Unknown mode ' + this.mode)
+  }
+}
+
+Zlib.prototype._checkError = function () {
+  // Acceptable error states depend on the type of zlib stream.
+  switch (this.err) {
+    case exports.Z_OK:
+    case exports.Z_BUF_ERROR:
+      if (this.strm.avail_out !== 0 && this.flush === exports.Z_FINISH) {
+        this._error('unexpected end of file')
+        return false
+      }
+      break
+    case exports.Z_STREAM_END:
+      // normal statuses, not fatal
+      break
+    case exports.Z_NEED_DICT:
+      if (this.dictionary == null) {
+        this._error('Missing dictionary')
+      } else {
+        this._error('Bad dictionary')
+      }
+      return false
+    default:
+      // something else.
+      this._error('Zlib error')
+      return false
+  }
+
+  return true
+}
+
+Zlib.prototype._after = function () {
+  if (!this._checkError()) {
+    return
+  }
+
+  var avail_out = this.strm.avail_out
+  var avail_in = this.strm.avail_in
+
+  this.write_in_progress = false
+
+  // call the write() cb
+  this.callback(avail_in, avail_out)
+
+  if (this.pending_close) {
+    this.close()
+  }
+}
+
+Zlib.prototype._error = function (message) {
+  if (this.strm.msg) {
+    message = this.strm.msg
+  }
+  this.onerror(message, this.err)
+
+  // no hope of rescue.
+  this.write_in_progress = false
+  if (this.pending_close) {
+    this.close()
+  }
+}
+
+Zlib.prototype.init = function (windowBits, level, memLevel, strategy, dictionary) {
+  assert(arguments.length === 4 || arguments.length === 5, 'init(windowBits, level, memLevel, strategy, [dictionary])')
+
+  assert(windowBits >= 8 && windowBits <= 15, 'invalid windowBits')
+  assert(level >= -1 && level <= 9, 'invalid compression level')
+
+  assert(memLevel >= 1 && memLevel <= 9, 'invalid memlevel')
+
+  assert(strategy === exports.Z_FILTERED ||
+         strategy === exports.Z_HUFFMAN_ONLY ||
+         strategy === exports.Z_RLE ||
+         strategy === exports.Z_FIXED ||
+         strategy === exports.Z_DEFAULT_STRATEGY, 'invalid strategy')
+
+  this._init(level, windowBits, memLevel, strategy, dictionary)
+  this._setDictionary()
+}
+
+Zlib.prototype.params = function () {
+  throw new Error('deflateParams Not supported')
+}
+
+Zlib.prototype.reset = function () {
+  this._reset()
+  this._setDictionary()
+}
+
+Zlib.prototype._init = function (level, windowBits, memLevel, strategy, dictionary) {
+  this.level = level
+  this.windowBits = windowBits
+  this.memLevel = memLevel
+  this.strategy = strategy
+
+  this.flush = exports.Z_NO_FLUSH
+
+  this.err = exports.Z_OK
+
+  if (this.mode === exports.GZIP || this.mode === exports.GUNZIP) {
+    this.windowBits += 16
+  }
+
+  if (this.mode === exports.UNZIP) {
+    this.windowBits += 32
+  }
+
+  if (this.mode === exports.DEFLATERAW || this.mode === exports.INFLATERAW) {
+    this.windowBits = -1 * this.windowBits
+  }
+
+  this.strm = new Zstream()
+
+  switch (this.mode) {
+    case exports.DEFLATE:
+    case exports.GZIP:
+    case exports.DEFLATERAW:
+      this.err = zlib_deflate.deflateInit2(
         this.strm,
         this.level,
         exports.Z_DEFLATED,
         this.windowBits,
         this.memLevel,
         this.strategy
-      );
-      break;
+      )
+      break
     case exports.INFLATE:
     case exports.GUNZIP:
     case exports.INFLATERAW:
     case exports.UNZIP:
-      var status  = zlib_inflate.inflateInit2(
+      this.err = zlib_inflate.inflateInit2(
         this.strm,
         this.windowBits
-      );
-      break;
+      )
+      break
     default:
-      throw new Error("Unknown mode " + this.mode);
-  }
-  
-  if (status !== exports.Z_OK) {
-    this._error(status);
-    return;
-  }
-  
-  this.write_in_progress = false;
-  this.init_done = true;
-};
-
-Zlib.prototype.params = function() {
-  throw new Error("deflateParams Not supported");
-};
-
-Zlib.prototype._writeCheck = function() {
-  if (!this.init_done)
-    throw new Error("write before init");
-    
-  if (this.mode === exports.NONE)
-    throw new Error("already finalized");
-    
-  if (this.write_in_progress)
-    throw new Error("write already in progress");
-    
-  if (this.pending_close)
-    throw new Error("close is pending");
-};
-
-Zlib.prototype.write = function(flush, input, in_off, in_len, out, out_off, out_len) {    
-  this._writeCheck();
-  this.write_in_progress = true;
-  
-  var self = this;
-  process.nextTick(function() {
-    self.write_in_progress = false;
-    var res = self._write(flush, input, in_off, in_len, out, out_off, out_len);
-    self.callback(res[0], res[1]);
-    
-    if (self.pending_close)
-      self.close();
-  });
-  
-  return this;
-};
-
-// set method for Node buffers, used by pako
-function bufferSet(data, offset) {
-  for (var i = 0; i < data.length; i++) {
-    this[offset + i] = data[i];
-  }
-}
-
-Zlib.prototype.writeSync = function(flush, input, in_off, in_len, out, out_off, out_len) {
-  this._writeCheck();
-  return this._write(flush, input, in_off, in_len, out, out_off, out_len);
-};
-
-Zlib.prototype._write = function(flush, input, in_off, in_len, out, out_off, out_len) {
-  this.write_in_progress = true;
-  
-  if (flush !== exports.Z_NO_FLUSH &&
-      flush !== exports.Z_PARTIAL_FLUSH &&
-      flush !== exports.Z_SYNC_FLUSH &&
-      flush !== exports.Z_FULL_FLUSH &&
-      flush !== exports.Z_FINISH &&
-      flush !== exports.Z_BLOCK) {
-    throw new Error("Invalid flush value");
-  }
-  
-  if (input == null) {
-    input = new Buffer(0);
-    in_len = 0;
-    in_off = 0;
-  }
-  
-  if (out._set)
-    out.set = out._set;
-  else
-    out.set = bufferSet;
-  
-  var strm = this.strm;
-  strm.avail_in = in_len;
-  strm.input = input;
-  strm.next_in = in_off;
-  strm.avail_out = out_len;
-  strm.output = out;
-  strm.next_out = out_off;
-  
+      throw new Error('Unknown mode ' + this.mode)
+  }
+
+  if (this.err !== exports.Z_OK) {
+    this._error('Init error')
+  }
+
+  this.dictionary = dictionary
+
+  this.write_in_progress = false
+  this.init_done = true
+}
+
+Zlib.prototype._setDictionary = function () {
+  if (this.dictionary == null) {
+    return
+  }
+
+  this.err = exports.Z_OK
+
   switch (this.mode) {
     case exports.DEFLATE:
-    case exports.GZIP:
     case exports.DEFLATERAW:
-      var status = zlib_deflate.deflate(strm, flush);
-      break;
-    case exports.UNZIP:
-    case exports.INFLATE:
-    case exports.GUNZIP:
-    case exports.INFLATERAW:
-      var status = zlib_inflate.inflate(strm, flush);
-      break;
+      this.err = zlib_deflate.deflateSetDictionary(this.strm, this.dictionary)
+      break
     default:
-      throw new Error("Unknown mode " + this.mode);
+      break
   }
-  
-  if (status !== exports.Z_STREAM_END && status !== exports.Z_OK) {
-    this._error(status);
-  }
-  
-  this.write_in_progress = false;
-  return [strm.avail_in, strm.avail_out];
-};
 
-Zlib.prototype.close = function() {
-  if (this.write_in_progress) {
-    this.pending_close = true;
-    return;
-  }
-  
-  this.pending_close = false;
-  
-  if (this.mode === exports.DEFLATE || this.mode === exports.GZIP || this.mode === exports.DEFLATERAW) {
-    zlib_deflate.deflateEnd(this.strm);
-  } else {
-    zlib_inflate.inflateEnd(this.strm);
+  if (this.err !== exports.Z_OK) {
+    this._error('Failed to set dictionary')
   }
-  
-  this.mode = exports.NONE;
-};
+}
+
+Zlib.prototype._reset = function () {
+  this.err = exports.Z_OK
 
-Zlib.prototype.reset = function() {
   switch (this.mode) {
     case exports.DEFLATE:
     case exports.DEFLATERAW:
-      var status = zlib_deflate.deflateReset(this.strm);
-      break;
+    case exports.GZIP:
+      this.err = zlib_deflate.deflateReset(this.strm)
+      break
     case exports.INFLATE:
     case exports.INFLATERAW:
-      var status = zlib_inflate.inflateReset(this.strm);
-      break;
-  }
-  
-  if (status !== exports.Z_OK) {
-    this._error(status);
+    case exports.GUNZIP:
+      this.err = zlib_inflate.inflateReset(this.strm)
+      break
+    default:
+      break
   }
-};
 
-Zlib.prototype._error = function(status) {
-  this.onerror(msg[status] + ': ' + this.strm.msg, status);
-  
-  this.write_in_progress = false;
-  if (this.pending_close)
-    this.close();
-};
+  if (this.err !== exports.Z_OK) {
+    this._error('Failed to reset stream')
+  }
+}
 
-exports.Zlib = Zlib;
+exports.Zlib = Zlib
diff --git a/node_modules/browserify-zlib/src/index.js b/node_modules/browserify-zlib/src/index.js
index 032689c4a..12f1ad033 100644
--- a/node_modules/browserify-zlib/src/index.js
+++ b/node_modules/browserify-zlib/src/index.js
@@ -1,29 +1,13 @@
-// 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.
-
-var Transform = require('_stream_transform');
-
-var binding = require('./binding');
-var util = require('util');
-var assert = require('assert').ok;
+'use strict';
+
+const Buffer = require('buffer').Buffer;
+const Transform = require('stream').Transform;
+const binding = require('./binding');
+const util = require('util');
+const assert = require('assert').ok;
+const kMaxLength = require('buffer').kMaxLength;
+const kRangeErrorMessage = 'Cannot create final Buffer. It would be larger ' +
+                           'than 0x' + kMaxLength.toString(16) + ' bytes';
 
 // zlib doesn't provide these, so kludge them in following the same
 // const naming scheme zlib uses.
@@ -47,12 +31,18 @@ binding.Z_MAX_LEVEL = 9;
 binding.Z_DEFAULT_LEVEL = binding.Z_DEFAULT_COMPRESSION;
 
 // expose all the zlib constants
-Object.keys(binding).forEach(function(k) {
-  if (k.match(/^Z/)) exports[k] = binding[k];
-});
+const bkeys = Object.keys(binding);
+for (var bk = 0; bk < bkeys.length; bk++) {
+  var bkey = bkeys[bk];
+  if (bkey.match(/^Z/)) {
+    Object.defineProperty(exports, bkey, {
+      enumerable: true, value: binding[bkey], writable: false
+    });
+  }
+}
 
 // translation table for return codes.
-exports.codes = {
+const codes = {
   Z_OK: binding.Z_OK,
   Z_STREAM_END: binding.Z_STREAM_END,
   Z_NEED_DICT: binding.Z_NEED_DICT,
@@ -64,8 +54,14 @@ exports.codes = {
   Z_VERSION_ERROR: binding.Z_VERSION_ERROR
 };
 
-Object.keys(exports.codes).forEach(function(k) {
-  exports.codes[exports.codes[k]] = k;
+const ckeys = Object.keys(codes);
+for (var ck = 0; ck < ckeys.length; ck++) {
+  var ckey = ckeys[ck];
+  codes[codes[ckey]] = ckey;
+}
+
+Object.defineProperty(exports, 'codes', {
+  enumerable: true, value: Object.freeze(codes), writable: false
 });
 
 exports.Deflate = Deflate;
@@ -217,20 +213,29 @@ function zlibBuffer(engine, buffer, callback) {
   }
 
   function onEnd() {
-    var buf = Buffer.concat(buffers, nread);
+    var buf;
+    var err = null;
+
+    if (nread >= kMaxLength) {
+      err = new RangeError(kRangeErrorMessage);
+    } else {
+      buf = Buffer.concat(buffers, nread);
+    }
+
     buffers = [];
-    callback(null, buf);
     engine.close();
+    callback(err, buf);
   }
 }
 
 function zlibBufferSync(engine, buffer) {
   if (typeof buffer === 'string')
-    buffer = new Buffer(buffer);
+    buffer = Buffer.from(buffer);
+
   if (!Buffer.isBuffer(buffer))
     throw new TypeError('Not a string or buffer');
 
-  var flushFlag = binding.Z_FINISH;
+  var flushFlag = engine._finishFlushFlag;
 
   return engine._processChunk(buffer, flushFlag);
 }
@@ -248,7 +253,6 @@ function Inflate(opts) {
 }
 
 
-
 // gzip - bigger header, same deflate compression
 function Gzip(opts) {
   if (!(this instanceof Gzip)) return new Gzip(opts);
@@ -261,7 +265,6 @@ function Gunzip(opts) {
 }
 
 
-
 // raw - no header
 function DeflateRaw(opts) {
   if (!(this instanceof DeflateRaw)) return new DeflateRaw(opts);
@@ -280,6 +283,14 @@ function Unzip(opts) {
   Zlib.call(this, opts, binding.UNZIP);
 }
 
+function isValidFlushFlag(flag) {
+  return flag === binding.Z_NO_FLUSH ||
+         flag === binding.Z_PARTIAL_FLUSH ||
+         flag === binding.Z_SYNC_FLUSH ||
+         flag === binding.Z_FULL_FLUSH ||
+         flag === binding.Z_FINISH ||
+         flag === binding.Z_BLOCK;
+}
 
 // the Zlib class they all inherit from
 // This thing manages the queue of requests, and returns
@@ -292,17 +303,16 @@ function Zlib(opts, mode) {
 
   Transform.call(this, opts);
 
-  if (opts.flush) {
-    if (opts.flush !== binding.Z_NO_FLUSH &&
-        opts.flush !== binding.Z_PARTIAL_FLUSH &&
-        opts.flush !== binding.Z_SYNC_FLUSH &&
-        opts.flush !== binding.Z_FULL_FLUSH &&
-        opts.flush !== binding.Z_FINISH &&
-        opts.flush !== binding.Z_BLOCK) {
-      throw new Error('Invalid flush flag: ' + opts.flush);
-    }
+  if (opts.flush && !isValidFlushFlag(opts.flush)) {
+    throw new Error('Invalid flush flag: ' + opts.flush);
+  }
+  if (opts.finishFlush && !isValidFlushFlag(opts.finishFlush)) {
+    throw new Error('Invalid flush flag: ' + opts.finishFlush);
   }
+
   this._flushFlag = opts.flush || binding.Z_NO_FLUSH;
+  this._finishFlushFlag = typeof opts.finishFlush !== 'undefined' ?
+    opts.finishFlush : binding.Z_FINISH;
 
   if (opts.chunkSize) {
     if (opts.chunkSize < exports.Z_MIN_CHUNK ||
@@ -348,14 +358,14 @@ function Zlib(opts, mode) {
     }
   }
 
-  this._binding = new binding.Zlib(mode);
+  this._handle = new binding.Zlib(mode);
 
   var self = this;
   this._hadError = false;
-  this._binding.onerror = function(message, errno) {
+  this._handle.onerror = function(message, errno) {
     // there is no way to cleanly recover.
     // continuing only obscures problems.
-    self._binding = null;
+    _close(self);
     self._hadError = true;
 
     var error = new Error(message);
@@ -370,19 +380,24 @@ function Zlib(opts, mode) {
   var strategy = exports.Z_DEFAULT_STRATEGY;
   if (typeof opts.strategy === 'number') strategy = opts.strategy;
 
-  this._binding.init(opts.windowBits || exports.Z_DEFAULT_WINDOWBITS,
-                     level,
-                     opts.memLevel || exports.Z_DEFAULT_MEMLEVEL,
-                     strategy,
-                     opts.dictionary);
+  this._handle.init(opts.windowBits || exports.Z_DEFAULT_WINDOWBITS,
+                    level,
+                    opts.memLevel || exports.Z_DEFAULT_MEMLEVEL,
+                    strategy,
+                    opts.dictionary);
 
-  this._buffer = new Buffer(this._chunkSize);
+  this._buffer = Buffer.allocUnsafe(this._chunkSize);
   this._offset = 0;
-  this._closed = false;
   this._level = level;
   this._strategy = strategy;
 
   this.once('end', this.close);
+
+  Object.defineProperty(this, '_closed', {
+    get: () => { return !this._handle; },
+    configurable: true,
+    enumerable: true
+  });
 }
 
 util.inherits(Zlib, Transform);
@@ -403,7 +418,8 @@ Zlib.prototype.params = function(level, strategy, callback) {
   if (this._level !== level || this._strategy !== strategy) {
     var self = this;
     this.flush(binding.Z_SYNC_FLUSH, function() {
-      self._binding.params(level, strategy);
+      assert(self._handle, 'zlib binding closed');
+      self._handle.params(level, strategy);
       if (!self._hadError) {
         self._level = level;
         self._strategy = strategy;
@@ -416,19 +432,20 @@ Zlib.prototype.params = function(level, strategy, callback) {
 };
 
 Zlib.prototype.reset = function() {
-  return this._binding.reset();
+  assert(this._handle, 'zlib binding closed');
+  return this._handle.reset();
 };
 
 // This is the _flush function called by the transform class,
 // internally, when the last chunk has been written.
 Zlib.prototype._flush = function(callback) {
-  this._transform(new Buffer(0), '', callback);
+  this._transform(Buffer.alloc(0), '', callback);
 };
 
 Zlib.prototype.flush = function(kind, callback) {
   var ws = this._writableState;
 
-  if (typeof kind === 'function' || (kind === void 0 && !callback)) {
+  if (typeof kind === 'function' || (kind === undefined && !callback)) {
     callback = kind;
     kind = binding.Z_FULL_FLUSH;
   }
@@ -440,32 +457,35 @@ Zlib.prototype.flush = function(kind, callback) {
     if (callback)
       this.once('end', callback);
   } else if (ws.needDrain) {
-    var self = this;
-    this.once('drain', function() {
-      self.flush(callback);
-    });
+    if (callback) {
+      this.once('drain', () => this.flush(kind, callback));
+    }
   } else {
     this._flushFlag = kind;
-    this.write(new Buffer(0), '', callback);
+    this.write(Buffer.alloc(0), '', callback);
   }
 };
 
 Zlib.prototype.close = function(callback) {
+  _close(this, callback);
+  process.nextTick(emitCloseNT, this);
+};
+
+function _close(engine, callback) {
   if (callback)
     process.nextTick(callback);
 
-  if (this._closed)
+  // Caller may invoke .close after a zlib error (which will null _handle).
+  if (!engine._handle)
     return;
 
-  this._closed = true;
-
-  this._binding.close();
+  engine._handle.close();
+  engine._handle = null;
+}
 
-  var self = this;
-  process.nextTick(function() {
-    self.emit('close');
-  });
-};
+function emitCloseNT(self) {
+  self.emit('close');
+}
 
 Zlib.prototype._transform = function(chunk, encoding, cb) {
   var flushFlag;
@@ -473,15 +493,19 @@ Zlib.prototype._transform = function(chunk, encoding, cb) {
   var ending = ws.ending || ws.ended;
   var last = ending && (!chunk || ws.length === chunk.length);
 
-  if (!chunk === null && !Buffer.isBuffer(chunk))
+  if (chunk !== null && !Buffer.isBuffer(chunk))
     return cb(new Error('invalid input'));
 
-  // If it's the last chunk, or a final flush, we use the Z_FINISH flush flag.
+  if (!this._handle)
+    return cb(new Error('zlib binding closed'));
+
+  // If it's the last chunk, or a final flush, we use the Z_FINISH flush flag
+  // (or whatever flag was provided using opts.finishFlush).
   // If it's explicitly flushing at some other time, then we use
   // Z_FULL_FLUSH. Otherwise, use Z_NO_FLUSH for maximum compression
   // goodness.
   if (last)
-    flushFlag = binding.Z_FINISH;
+    flushFlag = this._finishFlushFlag;
   else {
     flushFlag = this._flushFlag;
     // once we've flushed the last of the queue, stop flushing and
@@ -491,7 +515,6 @@ Zlib.prototype._transform = function(chunk, encoding, cb) {
     }
   }
 
-  var self = this;
   this._processChunk(chunk, flushFlag, cb);
 };
 
@@ -513,38 +536,55 @@ Zlib.prototype._processChunk = function(chunk, flushFlag, cb) {
       error = er;
     });
 
+    assert(this._handle, 'zlib binding closed');
     do {
-      var res = this._binding.writeSync(flushFlag,
-                                        chunk, // in
-                                        inOff, // in_off
-                                        availInBefore, // in_len
-                                        this._buffer, // out
-                                        this._offset, //out_off
-                                        availOutBefore); // out_len
+      var res = this._handle.writeSync(flushFlag,
+                                       chunk, // in
+                                       inOff, // in_off
+                                       availInBefore, // in_len
+                                       this._buffer, // out
+                                       this._offset, //out_off
+                                       availOutBefore); // out_len
     } while (!this._hadError && callback(res[0], res[1]));
 
     if (this._hadError) {
       throw error;
     }
 
+    if (nread >= kMaxLength) {
+      _close(this);
+      throw new RangeError(kRangeErrorMessage);
+    }
+
     var buf = Buffer.concat(buffers, nread);
-    this.close();
+    _close(this);
 
     return buf;
   }
 
-  var req = this._binding.write(flushFlag,
-                                chunk, // in
-                                inOff, // in_off
-                                availInBefore, // in_len
-                                this._buffer, // out
-                                this._offset, //out_off
-                                availOutBefore); // out_len
+  assert(this._handle, 'zlib binding closed');
+  var req = this._handle.write(flushFlag,
+                               chunk, // in
+                               inOff, // in_off
+                               availInBefore, // in_len
+                               this._buffer, // out
+                               this._offset, //out_off
+                               availOutBefore); // out_len
 
   req.buffer = chunk;
   req.callback = callback;
 
   function callback(availInAfter, availOutAfter) {
+    // When the callback is used in an async write, the callback's
+    // context is the `req` object that was created. The req object
+    // is === this._handle, and that's why it's important to null
+    // out the values after they are done being used. `this._handle`
+    // can stay in memory longer than the callback and buffer are needed.
+    if (this) {
+      this.buffer = null;
+      this.callback = null;
+    }
+
     if (self._hadError)
       return;
 
@@ -567,7 +607,7 @@ Zlib.prototype._processChunk = function(chunk, flushFlag, cb) {
     if (availOutAfter === 0 || self._offset >= self._chunkSize) {
       availOutBefore = self._chunkSize;
       self._offset = 0;
-      self._buffer = new Buffer(self._chunkSize);
+      self._buffer = Buffer.allocUnsafe(self._chunkSize);
     }
 
     if (availOutAfter === 0) {
@@ -581,13 +621,13 @@ Zlib.prototype._processChunk = function(chunk, flushFlag, cb) {
       if (!async)
         return true;
 
-      var newReq = self._binding.write(flushFlag,
-                                       chunk,
-                                       inOff,
-                                       availInBefore,
-                                       self._buffer,
-                                       self._offset,
-                                       self._chunkSize);
+      var newReq = self._handle.write(flushFlag,
+                                      chunk,
+                                      inOff,
+                                      availInBefore,
+                                      self._buffer,
+                                      self._offset,
+                                      self._chunkSize);
       newReq.callback = callback; // this same function
       newReq.buffer = chunk;
       return;