lib,src: standardize `owner_symbol` for handles

Instead of somtimes using an `owner` string to link from a
native handle object to the corresponding JS object, standardize
on a single symbol that fulfills this role.

PR-URL: https://github.com/nodejs/node/pull/22002
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Jon Moss <me@jonathanmoss.me>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Minwoo Jung <minwoo@nodesource.com>
Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com>
Reviewed-By: Ali Ijaz Sheikh <ofrobots@google.com>

12 files changed, 77 insertions, 42 deletions

diff --git a/lib/_tls_wrap.js b/lib/_tls_wrap.js
index 225d65fee3..83da2721e8 100644
--- a/lib/_tls_wrap.js
+++ b/lib/_tls_wrap.js
@@ -35,6 +35,7 @@ const debug = util.debuglog('tls');
 const tls_wrap = process.binding('tls_wrap');
 const { TCP, constants: TCPConstants } = process.binding('tcp_wrap');
 const { Pipe, constants: PipeConstants } = process.binding('pipe_wrap');
+const { owner_symbol } = require('internal/async_hooks').symbols;
 const {
   SecureContext: NativeSecureContext
 } = process.binding('crypto');
@@ -76,7 +77,7 @@ function onhandshakestart(now) {
   else
     this.handshakes++;
 
-  const { owner } = this;
+  const owner = this[owner_symbol];
   if (this.handshakes > tls.CLIENT_RENEG_LIMIT) {
     owner._emitTLSError(new ERR_TLS_SESSION_ATTACK());
     return;
@@ -89,7 +90,7 @@ function onhandshakestart(now) {
 function onhandshakedone() {
   debug('onhandshakedone');
 
-  const owner = this.owner;
+  const owner = this[owner_symbol];
 
   // `newSession` callback wasn't called yet
   if (owner._newSessionPending) {
@@ -102,7 +103,7 @@ function onhandshakedone() {
 
 
 function loadSession(hello) {
-  const owner = this.owner;
+  const owner = this[owner_symbol];
 
   var once = false;
   function onSession(err, session) {
@@ -130,7 +131,7 @@ function loadSession(hello) {
 
 
 function loadSNI(info) {
-  const owner = this.owner;
+  const owner = this[owner_symbol];
   const servername = info.servername;
   if (!servername || !owner._SNICallback)
     return requestOCSP(owner, info);
@@ -212,7 +213,7 @@ function requestOCSPDone(socket) {
 
 
 function onnewsession(key, session) {
-  const owner = this.owner;
+  const owner = this[owner_symbol];
 
   if (!owner.server)
     return;
@@ -241,11 +242,11 @@ function onnewsession(key, session) {
 
 
 function onocspresponse(resp) {
-  this.owner.emit('OCSPResponse', resp);
+  this[owner_symbol].emit('OCSPResponse', resp);
 }
 
 function onerror(err) {
-  const owner = this.owner;
+  const owner = this[owner_symbol];
 
   if (owner._writableState.errorEmitted)
     return;
@@ -364,9 +365,9 @@ for (var n = 0; n < proxiedMethods.length; n++) {
 
 tls_wrap.TLSWrap.prototype.close = function close(cb) {
   let ssl;
-  if (this.owner) {
-    ssl = this.owner.ssl;
-    this.owner.ssl = null;
+  if (this[owner_symbol]) {
+    ssl = this[owner_symbol].ssl;
+    this[owner_symbol].ssl = null;
   }
 
   // Invoke `destroySSL` on close to clean up possibly pending write requests
@@ -405,7 +406,7 @@ TLSSocket.prototype._wrapHandle = function(wrap) {
     handle = options.pipe ?
       new Pipe(PipeConstants.SOCKET) :
       new TCP(TCPConstants.SOCKET);
-    handle.owner = this;
+    handle[owner_symbol] = this;
   }
 
   // Wrap socket's handle
diff --git a/lib/dgram.js b/lib/dgram.js
index 292f7daf87..8ddd523237 100644
--- a/lib/dgram.js
+++ b/lib/dgram.js
@@ -43,7 +43,7 @@ const { isUint8Array } = require('internal/util/types');
 const EventEmitter = require('events');
 const {
   defaultTriggerAsyncIdScope,
-  symbols: { async_id_symbol }
+  symbols: { async_id_symbol, owner_symbol }
 } = require('internal/async_hooks');
 const { UV_UDP_REUSEADDR } = process.binding('constants').os;
 
@@ -78,7 +78,7 @@ function Socket(type, listener) {
   }
 
   var handle = newHandle(type, lookup);
-  handle.owner = this;
+  handle[owner_symbol] = this;
 
   this[async_id_symbol] = handle.getAsyncId();
   this.type = type;
@@ -132,7 +132,7 @@ function replaceHandle(self, newHandle) {
   newHandle.lookup = oldHandle.lookup;
   newHandle.bind = oldHandle.bind;
   newHandle.send = oldHandle.send;
-  newHandle.owner = self;
+  newHandle[owner_symbol] = self;
 
   // Replace the existing handle by the handle we got from master.
   oldHandle.close();
@@ -635,7 +635,7 @@ function stopReceiving(socket) {
 
 
 function onMessage(nread, handle, buf, rinfo) {
-  var self = handle.owner;
+  var self = handle[owner_symbol];
   if (nread < 0) {
     return self.emit('error', errnoException(nread, 'recvmsg'));
   }
@@ -745,6 +745,14 @@ Socket.prototype._stopReceiving = function() {
 };
 
 
+// Legacy alias on the C++ wrapper object. This is not public API, so we may
+// want to runtime-deprecate it at some point. There's no hurry, though.
+Object.defineProperty(UDP.prototype, 'owner', {
+  get() { return this[owner_symbol]; },
+  set(v) { return this[owner_symbol] = v; }
+});
+
+
 module.exports = {
   _createSocketHandle,
   createSocket,
diff --git a/lib/internal/async_hooks.js b/lib/internal/async_hooks.js
index 90155fa3c7..9edb23f8a6 100644
--- a/lib/internal/async_hooks.js
+++ b/lib/internal/async_hooks.js
@@ -30,7 +30,7 @@ const async_wrap = process.binding('async_wrap');
  * It has a fixed size, so if that is exceeded, calls to the native
  * side are used instead in pushAsyncIds() and popAsyncIds().
  */
-const { async_hook_fields, async_id_fields } = async_wrap;
+const { async_hook_fields, async_id_fields, owner_symbol } = async_wrap;
 // Store the pair executionAsyncId and triggerAsyncId in a std::stack on
 // Environment::AsyncHooks::async_ids_stack_ tracks the resource responsible for
 // the current execution stack. This is unwound as each resource exits. In the
@@ -434,7 +434,7 @@ module.exports = {
   symbols: {
     async_id_symbol, trigger_async_id_symbol,
     init_symbol, before_symbol, after_symbol, destroy_symbol,
-    promise_resolve_symbol
+    promise_resolve_symbol, owner_symbol
   },
   constants: {
     kInit, kBefore, kAfter, kDestroy, kTotals, kPromiseResolve
diff --git a/lib/internal/child_process.js b/lib/internal/child_process.js
index d22009505a..558932d341 100644
--- a/lib/internal/child_process.js
+++ b/lib/internal/child_process.js
@@ -27,6 +27,7 @@ const { TTY } = process.binding('tty_wrap');
 const { TCP } = process.binding('tcp_wrap');
 const { UDP } = process.binding('udp_wrap');
 const SocketList = require('internal/socket_list');
+const { owner_symbol } = require('internal/async_hooks').symbols;
 const { convertToValidSignal } = require('internal/util');
 const { isUint8Array } = require('internal/util/types');
 const spawn_sync = process.binding('spawn_sync');
@@ -209,7 +210,7 @@ function ChildProcess() {
   this.spawnfile = null;
 
   this._handle = new Process();
-  this._handle.owner = this;
+  this._handle[owner_symbol] = this;
 
   this._handle.onexit = (exitCode, signalCode) => {
     if (signalCode) {
diff --git a/lib/internal/cluster/child.js b/lib/internal/cluster/child.js
index 40c1a12327..39e891214f 100644
--- a/lib/internal/cluster/child.js
+++ b/lib/internal/cluster/child.js
@@ -3,6 +3,7 @@ const assert = require('assert');
 const util = require('util');
 const path = require('path');
 const EventEmitter = require('events');
+const { owner_symbol } = require('internal/async_hooks').symbols;
 const Worker = require('internal/cluster/worker');
 const { internal, sendHelper } = require('internal/cluster/utils');
 const cluster = new EventEmitter();
@@ -207,8 +208,8 @@ function _disconnect(masterInitiated) {
     delete handles[key];
     waitingCount++;
 
-    if (handle.owner)
-      handle.owner.close(checkWaitingCount);
+    if (handle[owner_symbol])
+      handle[owner_symbol].close(checkWaitingCount);
     else
       handle.close(checkWaitingCount);
   }
diff --git a/lib/internal/fs/watchers.js b/lib/internal/fs/watchers.js
index e7edc1c5ac..90ea3971aa 100644
--- a/lib/internal/fs/watchers.js
+++ b/lib/internal/fs/watchers.js
@@ -11,7 +11,10 @@ const {
   getStatsFromBinding,
   validatePath
 } = require('internal/fs/utils');
-const { defaultTriggerAsyncIdScope } = require('internal/async_hooks');
+const {
+  defaultTriggerAsyncIdScope,
+  symbols: { owner_symbol }
+} = require('internal/async_hooks');
 const { toNamespacedPath } = require('path');
 const { validateUint32 } = require('internal/validators');
 const { getPathFromURL } = require('internal/url');
@@ -20,7 +23,6 @@ const assert = require('assert');
 
 const kOldStatus = Symbol('kOldStatus');
 const kUseBigint = Symbol('kUseBigint');
-const kOwner = Symbol('kOwner');
 
 function emitStop(self) {
   self.emit('stop');
@@ -36,7 +38,7 @@ function StatWatcher(bigint) {
 util.inherits(StatWatcher, EventEmitter);
 
 function onchange(newStatus, stats) {
-  const self = this[kOwner];
+  const self = this[owner_symbol];
   if (self[kOldStatus] === -1 &&
       newStatus === -1 &&
       stats[2/* new nlink */] === stats[16/* old nlink */]) {
@@ -59,7 +61,7 @@ StatWatcher.prototype.start = function(filename, persistent, interval) {
     return;
 
   this._handle = new _StatWatcher(this[kUseBigint]);
-  this._handle[kOwner] = this;
+  this._handle[owner_symbol] = this;
   this._handle.onchange = onchange;
   if (!persistent)
     this._handle.unref();
@@ -104,7 +106,7 @@ function FSWatcher() {
   EventEmitter.call(this);
 
   this._handle = new FSEvent();
-  this._handle.owner = this;
+  this._handle[owner_symbol] = this;
 
   this._handle.onchange = (status, eventType, filename) => {
     // TODO(joyeecheung): we may check self._handle.initialized here
@@ -131,6 +133,7 @@ function FSWatcher() {
 }
 util.inherits(FSWatcher, EventEmitter);
 
+
 // FIXME(joyeecheung): this method is not documented.
 // At the moment if filename is undefined, we
 // 1. Throw an Error if it's the first time .start() is called
@@ -187,6 +190,13 @@ function emitCloseNT(self) {
   self.emit('close');
 }
 
+// Legacy alias on the C++ wrapper object. This is not public API, so we may
+// want to runtime-deprecate it at some point. There's no hurry, though.
+Object.defineProperty(FSEvent.prototype, 'owner', {
+  get() { return this[owner_symbol]; },
+  set(v) { return this[owner_symbol] = v; }
+});
+
 module.exports = {
   FSWatcher,
   StatWatcher
diff --git a/lib/internal/http2/core.js b/lib/internal/http2/core.js
index 18c0c4ce4c..568980c927 100644
--- a/lib/internal/http2/core.js
+++ b/lib/internal/http2/core.js
@@ -28,6 +28,7 @@ const {
   defaultTriggerAsyncIdScope,
   symbols: {
     async_id_symbol,
+    owner_symbol,
   },
 } = require('internal/async_hooks');
 const { internalBinding } = require('internal/bootstrap/loaders');
@@ -141,7 +142,7 @@ const kInfoHeaders = Symbol('sent-info-headers');
 const kMaybeDestroy = Symbol('maybe-destroy');
 const kLocalSettings = Symbol('local-settings');
 const kOptions = Symbol('options');
-const kOwner = Symbol('owner');
+const kOwner = owner_symbol;
 const kProceed = Symbol('proceed');
 const kProtocol = Symbol('protocol');
 const kProxySocket = Symbol('proxy-socket');
diff --git a/lib/internal/wrap_js_stream.js b/lib/internal/wrap_js_stream.js
index ec966028a0..e80716059e 100644
--- a/lib/internal/wrap_js_stream.js
+++ b/lib/internal/wrap_js_stream.js
@@ -6,16 +6,17 @@ const { Socket } = require('net');
 const { JSStream } = process.binding('js_stream');
 const uv = process.binding('uv');
 const debug = util.debuglog('stream_wrap');
+const { owner_symbol } = require('internal/async_hooks').symbols;
 const { ERR_STREAM_WRAP } = require('internal/errors').codes;
 
 const kCurrentWriteRequest = Symbol('kCurrentWriteRequest');
 const kCurrentShutdownRequest = Symbol('kCurrentShutdownRequest');
 
-function isClosing() { return this.owner.isClosing(); }
-function onreadstart() { return this.owner.readStart(); }
-function onreadstop() { return this.owner.readStop(); }
-function onshutdown(req) { return this.owner.doShutdown(req); }
-function onwrite(req, bufs) { return this.owner.doWrite(req, bufs); }
+function isClosing() { return this[owner_symbol].isClosing(); }
+function onreadstart() { return this[owner_symbol].readStart(); }
+function onreadstop() { return this[owner_symbol].readStop(); }
+function onshutdown(req) { return this[owner_symbol].doShutdown(req); }
+function onwrite(req, bufs) { return this[owner_symbol].doWrite(req, bufs); }
 
 /* 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
@@ -37,7 +38,7 @@ class JSStreamWrap extends Socket {
       this.doClose(cb);
     };
     // Inside of the following functions, `this` refers to the handle
-    // and `this.owner` refers to this JSStreamWrap instance.
+    // and `this[owner_symbol]` refers to this JSStreamWrap instance.
     handle.isClosing = isClosing;
     handle.onreadstart = onreadstart;
     handle.onreadstop = onreadstop;
diff --git a/lib/net.js b/lib/net.js
index 889f28b0aa..8c05f2c07b 100644
--- a/lib/net.js
+++ b/lib/net.js
@@ -56,7 +56,7 @@ const {
 const {
   newAsyncId,
   defaultTriggerAsyncIdScope,
-  symbols: { async_id_symbol }
+  symbols: { async_id_symbol, owner_symbol }
 } = require('internal/async_hooks');
 const {
   createWriteWrap,
@@ -207,7 +207,7 @@ function initSocketHandle(self) {
 
   // Handle creation may be deferred to bind() or connect() time.
   if (self._handle) {
-    self._handle.owner = self;
+    self._handle[owner_symbol] = self;
     self._handle.onread = onread;
     self[async_id_symbol] = getNewAsyncId(self._handle);
   }
@@ -371,7 +371,7 @@ Socket.prototype._final = function(cb) {
 
 
 function afterShutdown(status, handle) {
-  var self = handle.owner;
+  var self = handle[owner_symbol];
 
   debug('afterShutdown destroyed=%j', self.destroyed,
         self._readableState);
@@ -620,7 +620,7 @@ Socket.prototype._destroy = function(exception, cb) {
 // buffer, or when there's an error reading.
 function onread(nread, buffer) {
   var handle = this;
-  var self = handle.owner;
+  var self = handle[owner_symbol];
   assert(handle === self._handle, 'handle != self._handle');
 
   self._unrefTimer();
@@ -819,7 +819,7 @@ protoGetter('bytesWritten', function bytesWritten() {
 
 
 function afterWrite(status, handle, err) {
-  var self = handle.owner;
+  var self = handle[owner_symbol];
   if (self !== process.stderr && self !== process.stdout)
     debug('afterWrite', status);
 
@@ -1123,7 +1123,7 @@ Socket.prototype.unref = function() {
 
 
 function afterConnect(status, handle, req, readable, writable) {
-  var self = handle.owner;
+  var self = handle[owner_symbol];
 
   // callback may come after call to destroy
   if (self.destroyed) {
@@ -1325,7 +1325,7 @@ function setupListenHandle(address, port, addressType, backlog, fd) {
 
   this[async_id_symbol] = getNewAsyncId(this._handle);
   this._handle.onconnection = onconnection;
-  this._handle.owner = this;
+  this._handle[owner_symbol] = this;
 
   // Use a backlog of 512 entries. We pass 511 to the listen() call because
   // the kernel does: backlogsize = roundup_pow_of_two(backlogsize + 1);
@@ -1538,7 +1538,7 @@ Server.prototype.address = function() {
 
 function onconnection(err, clientHandle) {
   var handle = this;
-  var self = handle.owner;
+  var self = handle[owner_symbol];
 
   debug('onconnection');
 
@@ -1669,6 +1669,14 @@ function emitCloseNT(self) {
 }
 
 
+// Legacy alias on the C++ wrapper object. This is not public API, so we may
+// want to runtime-deprecate it at some point. There's no hurry, though.
+Object.defineProperty(TCP.prototype, 'owner', {
+  get() { return this[owner_symbol]; },
+  set(v) { return this[owner_symbol] = v; }
+});
+
+
 Server.prototype.listenFD = internalUtil.deprecate(function(fd, type) {
   return this.listen({ fd: fd });
 }, 'Server.listenFD is deprecated. Use Server.listen({fd: <number>}) instead.',
diff --git a/src/async_wrap.cc b/src/async_wrap.cc
index 7ef3dafdf9..9d9d03b0fa 100644
--- a/src/async_wrap.cc
+++ b/src/async_wrap.cc
@@ -481,6 +481,10 @@ void AsyncWrap::Initialize(Local<Object> target,
               env->async_ids_stack_string(),
               env->async_hooks()->async_ids_stack().GetJSArray()).FromJust();
 
+  target->Set(context,
+              FIXED_ONE_BYTE_STRING(env->isolate(), "owner_symbol"),
+              env->owner_symbol()).FromJust();
+
   Local<Object> constants = Object::New(isolate);
 #define SET_HOOKS_CONSTANT(name)                                              \
   FORCE_SET_TARGET_FIELD(                                                     \
diff --git a/src/env.h b/src/env.h
index 8e6da729c4..290ac89fb5 100644
--- a/src/env.h
+++ b/src/env.h
@@ -111,6 +111,7 @@ struct PackageConfig {
 // for the sake of convenience.
 #define PER_ISOLATE_SYMBOL_PROPERTIES(V)                                      \
   V(handle_onclose_symbol, "handle_onclose")                                  \
+  V(owner_symbol, "owner")                                                    \
 
 // Strings are per-isolate primitives but Environment proxies them
 // for the sake of convenience.  Strings should be ASCII-only.
@@ -234,7 +235,6 @@ struct PackageConfig {
   V(openssl_error_stack, "opensslErrorStack")                                 \
   V(output_string, "output")                                                  \
   V(order_string, "order")                                                    \
-  V(owner_string, "owner")                                                    \
   V(parse_error_string, "Parse Error")                                        \
   V(password_string, "password")                                              \
   V(path_string, "path")                                                      \
diff --git a/src/tcp_wrap.cc b/src/tcp_wrap.cc
index 805e566bfa..e817087d97 100644
--- a/src/tcp_wrap.cc
+++ b/src/tcp_wrap.cc
@@ -81,7 +81,7 @@ void TCPWrap::Initialize(Local<Object> target,
   // Init properties
   t->InstanceTemplate()->Set(FIXED_ONE_BYTE_STRING(env->isolate(), "reading"),
                              Boolean::New(env->isolate(), false));
-  t->InstanceTemplate()->Set(env->owner_string(), Null(env->isolate()));
+  t->InstanceTemplate()->Set(env->owner_symbol(), Null(env->isolate()));
   t->InstanceTemplate()->Set(env->onread_string(), Null(env->isolate()));
   t->InstanceTemplate()->Set(env->onconnection_string(), Null(env->isolate()));