stream: make Duplex inherits from DuplexBase

Add ability to subclass `stream.Duplex` without inheriting the "no-half-open enforcer" regardless of the value of the `allowHalfOpen` option. PR-URL: nodejs#18974 Reviewed-By: Benjamin Gruenbaum <[email protected]> Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: Matteo Collina <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Chen Gang <[email protected]> Reviewed-By: Ruben Bridgewater <[email protected]>
marcushill · Mar 7, 2018 · df07169 · df07169
1 parent 42e9b48
commit df07169
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Showing 3 changed files with 35 additions and 22 deletions.
diff --git a/lib/_stream_duplex.js b/lib/_stream_duplex.js
@@ -29,33 +29,15 @@
 module.exports = Duplex;
 
 const util = require('util');
-const Readable = require('_stream_readable');
-const Writable = require('_stream_writable');
-
-util.inherits(Duplex, Readable);
-
-{
- // avoid scope creep, the keys array can then be collected
- const keys = Object.keys(Writable.prototype);
- for (var v = 0; v < keys.length; v++) {
- const method = keys[v];
- if (!Duplex.prototype[method])
- Duplex.prototype[method] = Writable.prototype[method];
- }
-}
+const DuplexBase = require('internal/streams/duplex_base');
+
+util.inherits(Duplex, DuplexBase);
 
 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;
+ DuplexBase.call(this, options);
 
  this.allowHalfOpen = true;
  if (options && options.allowHalfOpen === false) {

diff --git a/lib/internal/streams/duplex_base.js b/lib/internal/streams/duplex_base.js
@@ -0,0 +1,30 @@
+'use strict';
+
+const util = require('util');
+const Readable = require('_stream_readable');
+const Writable = require('_stream_writable');
+
+function DuplexBase(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;
+}
+
+util.inherits(DuplexBase, Readable);
+
+{
+ // Avoid scope creep, the keys array can then be collected.
+ const keys = Object.keys(Writable.prototype);
+ for (var v = 0; v < keys.length; v++) {
+ const method = keys[v];
+ if (!DuplexBase.prototype[method])
+ DuplexBase.prototype[method] = Writable.prototype[method];
+ }
+}
+
+module.exports = DuplexBase;
diff --git a/node.gyp b/node.gyp
@@ -146,6 +146,7 @@
  'lib/internal/streams/lazy_transform.js',
  'lib/internal/streams/async_iterator.js',
  'lib/internal/streams/BufferList.js',
+ 'lib/internal/streams/duplex_base.js',
  'lib/internal/streams/duplexpair.js',
  'lib/internal/streams/legacy.js',
  'lib/internal/streams/destroy.js',