From 545f5126190acacd14ce54799d1e3c5d6dcd9edb Mon Sep 17 00:00:00 2001
From: isaacs <i@izs.me>
Date: Mon, 8 Oct 2012 14:43:17 -0700
Subject: [PATCH] streams2: ctor guards on Stream classes

---
 lib/_stream_duplex.js      | 3 +++
 lib/_stream_passthrough.js | 3 +++
 lib/_stream_readable.js    | 3 +++
 lib/_stream_transform.js   | 3 +++
 lib/_stream_writable.js    | 6 ++++++
 5 files changed, 18 insertions(+)

diff --git a/lib/_stream_duplex.js b/lib/_stream_duplex.js
index 0256b0f2f2..30b4692233 100644
--- a/lib/_stream_duplex.js
+++ b/lib/_stream_duplex.js
@@ -37,6 +37,9 @@ Object.keys(Writable.prototype).forEach(function(method) {
 });
 
 function Duplex(options) {
+  if (!(this instanceof Duplex))
+    return new Duplex(options);
+
   Readable.call(this, options);
   Writable.call(this, options);
 
diff --git a/lib/_stream_passthrough.js b/lib/_stream_passthrough.js
index 5acd27b260..0f2fe14c78 100644
--- a/lib/_stream_passthrough.js
+++ b/lib/_stream_passthrough.js
@@ -30,6 +30,9 @@ var util = require('util');
 util.inherits(PassThrough, Transform);
 
 function PassThrough(options) {
+  if (!(this instanceof PassThrough))
+    return new PassThrough(options);
+
   Transform.call(this, options);
 }
 
diff --git a/lib/_stream_readable.js b/lib/_stream_readable.js
index 916ebc2056..180ab1d55b 100644
--- a/lib/_stream_readable.js
+++ b/lib/_stream_readable.js
@@ -59,6 +59,9 @@ function ReadableState(options) {
 }
 
 function Readable(options) {
+  if (!(this instanceof Readable))
+    return new Readable(options);
+
   this._readableState = new ReadableState(options, this);
   Stream.apply(this);
 }
diff --git a/lib/_stream_transform.js b/lib/_stream_transform.js
index 16f2cacb93..abf7479fdc 100644
--- a/lib/_stream_transform.js
+++ b/lib/_stream_transform.js
@@ -77,6 +77,9 @@ function TransformState() {
 }
 
 function Transform(options) {
+  if (!(this instanceof Transform))
+    return new Transform(options);
+
   Duplex.call(this, options);
 
   // bind output so that it can be passed around as a regular function.
diff --git a/lib/_stream_writable.js b/lib/_stream_writable.js
index 90aa285865..ce56afdff9 100644
--- a/lib/_stream_writable.js
+++ b/lib/_stream_writable.js
@@ -27,6 +27,7 @@ module.exports = Writable
 
 var util = require('util');
 var Stream = require('stream');
+var Duplex = Stream.Duplex;
 
 util.inherits(Writable, Stream);
 
@@ -51,6 +52,11 @@ function WritableState(options) {
 }
 
 function Writable(options) {
+  // 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);
 
   // legacy.