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>

1 files changed, 15 insertions, 5 deletions

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