lib: refactor wrap_js_stream for ES6/readability

PR-URL: https://github.com/nodejs/node/pull/16158
Backport-PR-URL: https://github.com/nodejs/node/pull/16626
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Franziska Hinkelmann <franziska.hinkelmann@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>

3 files changed, 183 insertions, 187 deletions

diff --git a/lib/internal/wrap_js_stream.js b/lib/internal/wrap_js_stream.js
index 25a77b8c4a..9e0961654d 100644
--- a/lib/internal/wrap_js_stream.js
+++ b/lib/internal/wrap_js_stream.js
@@ -2,226 +2,222 @@
 
 const assert = require('assert');
 const util = require('util');
-const Socket = require('net').Socket;
-const JSStream = process.binding('js_stream').JSStream;
+const { Socket } = require('net');
+const { JSStream } = process.binding('js_stream');
 // TODO(bmeurer): Change this back to const once hole checks are
 // properly optimized away early in Ignition+TurboFan.
 var Buffer = require('buffer').Buffer;
 const uv = process.binding('uv');
 const debug = util.debuglog('stream_wrap');
 
-function StreamWrap(stream) {
-  const handle = new JSStream();
-
-  this.stream = stream;
-
-  this._list = null;
-
-  const self = this;
-  handle.close = function(cb) {
-    debug('close');
-    self.doClose(cb);
-  };
-  handle.isAlive = function() {
-    return self.isAlive();
-  };
-  handle.isClosing = function() {
-    return self.isClosing();
-  };
-  handle.onreadstart = function() {
-    return self.readStart();
-  };
-  handle.onreadstop = function() {
-    return self.readStop();
-  };
-  handle.onshutdown = function(req) {
-    return self.doShutdown(req);
-  };
-  handle.onwrite = function(req, bufs) {
-    return self.doWrite(req, bufs);
-  };
-
-  this.stream.pause();
-  this.stream.on('error', function onerror(err) {
-    self.emit('error', err);
-  });
-  this.stream.on('data', function ondata(chunk) {
-    if (!(chunk instanceof Buffer)) {
-      // Make sure that no further `data` events will happen
-      this.pause();
-      this.removeListener('data', ondata);
-
-      self.emit('error', new Error('Stream has StringDecoder'));
-      return;
-    }
-
-    debug('data', chunk.length);
-    if (self._handle)
-      self._handle.readBuffer(chunk);
-  });
-  this.stream.once('end', function onend() {
-    debug('end');
-    if (self._handle)
-      self._handle.emitEOF();
-  });
-
-  Socket.call(this, {
-    handle: handle
-  });
-}
-util.inherits(StreamWrap, Socket);
-module.exports = StreamWrap;
-
-// require('_stream_wrap').StreamWrap
-StreamWrap.StreamWrap = StreamWrap;
-
-StreamWrap.prototype.isAlive = function isAlive() {
-  return true;
-};
-
-StreamWrap.prototype.isClosing = function isClosing() {
-  return !this.readable || !this.writable;
-};
-
-StreamWrap.prototype.readStart = function readStart() {
-  this.stream.resume();
-  return 0;
-};
-
-StreamWrap.prototype.readStop = function readStop() {
-  this.stream.pause();
-  return 0;
-};
-
-StreamWrap.prototype.doShutdown = function doShutdown(req) {
-  const self = this;
-  const handle = this._handle;
-  const item = this._enqueue('shutdown', req);
-
-  this.stream.end(function() {
-    // Ensure that write was dispatched
-    setImmediate(function() {
-      if (!self._dequeue(item))
+/* This class serves as a wrapper for when the C++ side of Node wants access
+ * to a standard JS stream. For example, TLS or HTTP do not operate on network
+ * resources conceptually, although that is the common case and what we are
+ * optimizing for; in theory, they are completely composable and can work with
+ * any stream resource they see.
+ *
+ * For the common case, i.e. a TLS socket wrapping around a net.Socket, we
+ * can skip going through the JS layer and let TLS access the raw C++ handle
+ * of a net.Socket. The flipside of this is that, to maintain composability,
+ * we need a way to create "fake" net.Socket instances that call back into a
+ * "real" JavaScript stream. JSStreamWrap is exactly this.
+ */
+class JSStreamWrap extends Socket {
+  constructor(stream) {
+    const handle = new JSStream();
+    handle.close = (cb) => {
+      debug('close');
+      this.doClose(cb);
+    };
+    handle.isAlive = () => this.isAlive();
+    handle.isClosing = () => this.isClosing();
+    handle.onreadstart = () => this.readStart();
+    handle.onreadstop = () => this.readStop();
+    handle.onshutdown = (req) => this.doShutdown(req);
+    handle.onwrite = (req, bufs) => this.doWrite(req, bufs);
+
+    stream.pause();
+    stream.on('error', (err) => this.emit('error', err));
+    const ondata = (chunk) => {
+      if (!(chunk instanceof Buffer)) {
+        // Make sure that no further `data` events will happen.
+        stream.pause();
+        stream.removeListener('data', ondata);
+
+        this.emit('error', new Error('Stream has StringDecoder'));
         return;
+      }
 
-      handle.finishShutdown(req, 0);
+      debug('data', chunk.length);
+      if (this._handle)
+        this._handle.readBuffer(chunk);
+    };
+    stream.on('data', ondata);
+    stream.once('end', () => {
+      debug('end');
+      if (this._handle)
+        this._handle.emitEOF();
     });
-  });
-  return 0;
-};
 
-StreamWrap.prototype.doWrite = function doWrite(req, bufs) {
-  const self = this;
-  const handle = self._handle;
+    super({ handle, manualStart: true });
+    this.stream = stream;
+    this._list = null;
+    this.read(0);
+  }
 
-  var pending = bufs.length;
+  // Legacy
+  static get StreamWrap() {
+    return JSStreamWrap;
+  }
 
-  // Queue the request to be able to cancel it
-  const item = self._enqueue('write', req);
+  isAlive() {
+    return true;
+  }
 
-  self.stream.cork();
-  for (var n = 0; n < bufs.length; n++)
-    self.stream.write(bufs[n], done);
-  self.stream.uncork();
+  isClosing() {
+    return !this.readable || !this.writable;
+  }
 
-  function done(err) {
-    if (!err && --pending !== 0)
-      return;
+  readStart() {
+    this.stream.resume();
+    return 0;
+  }
 
-    // Ensure that this is called once in case of error
-    pending = 0;
+  readStop() {
+    this.stream.pause();
+    return 0;
+  }
 
-    // Ensure that write was dispatched
-    setImmediate(function() {
-      // Do not invoke callback twice
-      if (!self._dequeue(item))
-        return;
+  doShutdown(req) {
+    const handle = this._handle;
+    const item = this._enqueue('shutdown', req);
 
-      var errCode = 0;
-      if (err) {
-        if (err.code && uv['UV_' + err.code])
-          errCode = uv['UV_' + err.code];
-        else
-          errCode = uv.UV_EPIPE;
-      }
+    this.stream.end(() => {
+      // Ensure that write was dispatched
+      setImmediate(() => {
+        if (!this._dequeue(item))
+          return;
 
-      handle.doAfterWrite(req);
-      handle.finishWrite(req, errCode);
+        handle.finishShutdown(req, 0);
+      });
     });
+    return 0;
   }
 
-  return 0;
-};
+  doWrite(req, bufs) {
+    const self = this;
+    const handle = this._handle;
 
-function QueueItem(type, req) {
-  this.type = type;
-  this.req = req;
-  this.prev = this;
-  this.next = this;
-}
+    var pending = bufs.length;
 
-StreamWrap.prototype._enqueue = function _enqueue(type, req) {
-  const item = new QueueItem(type, req);
-  if (this._list === null) {
-    this._list = item;
-    return item;
-  }
+    // Queue the request to be able to cancel it
+    const item = this._enqueue('write', req);
 
-  item.next = this._list.next;
-  item.prev = this._list;
-  item.next.prev = item;
-  item.prev.next = item;
+    this.stream.cork();
+    for (var n = 0; n < bufs.length; n++)
+      this.stream.write(bufs[n], done);
+    this.stream.uncork();
 
-  return item;
-};
+    function done(err) {
+      if (!err && --pending !== 0)
+        return;
 
-StreamWrap.prototype._dequeue = function _dequeue(item) {
-  assert(item instanceof QueueItem);
+      // Ensure that this is called once in case of error
+      pending = 0;
 
-  var next = item.next;
-  var prev = item.prev;
+      // Ensure that write was dispatched
+      setImmediate(function() {
+        // Do not invoke callback twice
+        if (!self._dequeue(item))
+          return;
 
-  if (next === null && prev === null)
-    return false;
+        var errCode = 0;
+        if (err) {
+          if (err.code && uv['UV_' + err.code])
+            errCode = uv['UV_' + err.code];
+          else
+            errCode = uv.UV_EPIPE;
+        }
 
-  item.next = null;
-  item.prev = null;
+        handle.doAfterWrite(req);
+        handle.finishWrite(req, errCode);
+      });
+    }
 
-  if (next === item) {
-    prev = null;
-    next = null;
-  } else {
-    prev.next = next;
-    next.prev = prev;
+    return 0;
   }
 
-  if (this._list === item)
-    this._list = next;
+  _enqueue(type, req) {
+    const item = new QueueItem(type, req);
+    if (this._list === null) {
+      this._list = item;
+      return item;
+    }
 
-  return true;
-};
+    item.next = this._list.next;
+    item.prev = this._list;
+    item.next.prev = item;
+    item.prev.next = item;
 
-StreamWrap.prototype.doClose = function doClose(cb) {
-  const self = this;
-  const handle = self._handle;
+    return item;
+  }
 
-  setImmediate(function() {
-    while (self._list !== null) {
-      const item = self._list;
-      const req = item.req;
-      self._dequeue(item);
+  _dequeue(item) {
+    assert(item instanceof QueueItem);
 
-      const errCode = uv.UV_ECANCELED;
-      if (item.type === 'write') {
-        handle.doAfterWrite(req);
-        handle.finishWrite(req, errCode);
-      } else if (item.type === 'shutdown') {
-        handle.finishShutdown(req, errCode);
-      }
+    var next = item.next;
+    var prev = item.prev;
+
+    if (next === null && prev === null)
+      return false;
+
+    item.next = null;
+    item.prev = null;
+
+    if (next === item) {
+      prev = null;
+      next = null;
+    } else {
+      prev.next = next;
+      next.prev = prev;
     }
 
-    // Should be already set by net.js
-    assert(self._handle === null);
-    cb();
-  });
-};
+    if (this._list === item)
+      this._list = next;
+
+    return true;
+  }
+
+  doClose(cb) {
+    const handle = this._handle;
+
+    setImmediate(() => {
+      while (this._list !== null) {
+        const item = this._list;
+        const req = item.req;
+        this._dequeue(item);
+
+        const errCode = uv.UV_ECANCELED;
+        if (item.type === 'write') {
+          handle.doAfterWrite(req);
+          handle.finishWrite(req, errCode);
+        } else if (item.type === 'shutdown') {
+          handle.finishShutdown(req, errCode);
+        }
+      }
+
+      // Should be already set by net.js
+      assert.strictEqual(this._handle, null);
+      cb();
+    });
+  }
+}
+
+function QueueItem(type, req) {
+  this.type = type;
+  this.req = req;
+  this.prev = this;
+  this.next = this;
+}
+
+module.exports = JSStreamWrap;
diff --git a/lib/net.js b/lib/net.js
index 70d4841d5e..8e4377cb41 100644
--- a/lib/net.js
+++ b/lib/net.js
@@ -241,7 +241,7 @@ function Socket(options) {
       this._handle.reading = false;
       this._handle.readStop();
       this._readableState.flowing = false;
-    } else {
+    } else if (!options.manualStart) {
       this.read(0);
     }
   }
diff --git a/test/parallel/test-tls-wrap-event-emmiter.js b/test/parallel/test-tls-wrap-event-emmiter.js
index 82953f1333..b6ae9e2d5a 100644
--- a/test/parallel/test-tls-wrap-event-emmiter.js
+++ b/test/parallel/test-tls-wrap-event-emmiter.js
@@ -15,5 +15,5 @@ const TlsSocket = require('tls').TLSSocket;
 const EventEmitter = require('events').EventEmitter;
 assert.throws(
   () => { new TlsSocket(new EventEmitter()); },
-  /^TypeError: this\.stream\.pause is not a function/
+  /^TypeError: (.+) is not a function$/
 );