fs: make stats date fields lazy

PR-URL: #50908
Reviewed-By: Raz Luvaton <[email protected]>
Reviewed-By: Moshe Atlow <[email protected]>
Reviewed-By: Matteo Collina <[email protected]>

Author: anonrig

lib/internal/fs/utils.js

@@ -12,6 +12,8 @@ const {
   NumberIsFinite,
   MathMin,
   MathRound,
+  ObjectDefineProperties,
+  ObjectDefineProperty,
   ObjectIs,
   ObjectSetPrototypeOf,
   ReflectApply,
@@ -449,6 +451,62 @@ function dateFromMs(ms) {
   return new Date(MathRound(Number(ms)));
 }
 
+const lazyDateFields = {
+  __proto__: null,
+  atime: {
+    __proto__: null,
+    enumerable: true,
+    configurable: true,
+    get() {
+      const value = dateFromMs(this.atimeMs);
+      ObjectDefineProperty(this, 'atime', { __proto__: null, value });
+      return this.atime;
+    },
+    set(value) {
+      this.atime = value;
+    },
+  },
+  mtime: {
+    __proto__: null,
+    enumerable: true,
+    configurable: true,
+    get() {
+      const value = dateFromMs(this.mtimeMs);
+      ObjectDefineProperty(this, 'mtime', { __proto__: null, value });
+      return this.mtime;
+    },
+    set(value) {
+      this.mtime = value;
+    },
+  },
+  ctime: {
+    __proto__: null,
+    enumerable: true,
+    configurable: true,
+    get() {
+      const value = dateFromMs(this.ctimeMs);
+      ObjectDefineProperty(this, 'ctime', { __proto__: null, value });
+      return this.ctime;
+    },
+    set(value) {
+      this.ctime = value;
+    },
+  },
+  birthtime: {
+    __proto__: null,
+    enumerable: true,
+    configurable: true,
+    get() {
+      const value = dateFromMs(this.birthtimeMs);
+      ObjectDefineProperty(this, 'birthtime', { __proto__: null, value });
+      return this.birthtime;
+    },
+    set(value) {
+      this.birthtime = value;
+    },
+  },
+};
+
 function BigIntStats(dev, mode, nlink, uid, gid, rdev, blksize,
                      ino, size, blocks,
                      atimeNs, mtimeNs, ctimeNs, birthtimeNs) {
@@ -463,14 +521,11 @@ function BigIntStats(dev, mode, nlink, uid, gid, rdev, blksize,
   this.mtimeNs = mtimeNs;
   this.ctimeNs = ctimeNs;
   this.birthtimeNs = birthtimeNs;
-  this.atime = dateFromMs(this.atimeMs);
-  this.mtime = dateFromMs(this.mtimeMs);
-  this.ctime = dateFromMs(this.ctimeMs);
-  this.birthtime = dateFromMs(this.birthtimeMs);
 }
 
 ObjectSetPrototypeOf(BigIntStats.prototype, StatsBase.prototype);
 ObjectSetPrototypeOf(BigIntStats, StatsBase);
+ObjectDefineProperties(BigIntStats.prototype, lazyDateFields);
 
 BigIntStats.prototype._checkModeProperty = function(property) {
   if (isWindows && (property === S_IFIFO || property === S_IFBLK ||
@@ -489,14 +544,11 @@ function Stats(dev, mode, nlink, uid, gid, rdev, blksize,
   this.mtimeMs = mtimeMs;
   this.ctimeMs = ctimeMs;
   this.birthtimeMs = birthtimeMs;
-  this.atime = dateFromMs(atimeMs);
-  this.mtime = dateFromMs(mtimeMs);
-  this.ctime = dateFromMs(ctimeMs);
-  this.birthtime = dateFromMs(birthtimeMs);
 }
 
 ObjectSetPrototypeOf(Stats.prototype, StatsBase.prototype);
 ObjectSetPrototypeOf(Stats, StatsBase);
+ObjectDefineProperties(Stats.prototype, lazyDateFields);
 
 Stats.prototype._checkModeProperty = function(property) {
   if (isWindows && (property === S_IFIFO || property === S_IFBLK ||

test/parallel/test-fs-stat.js

@@ -80,8 +80,6 @@ fs.stat(__filename, common.mustSucceed((s) => {
   assert.strictEqual(s.isFIFO(), false);
   assert.strictEqual(s.isSymbolicLink(), false);
 
-  const jsonString = JSON.stringify(s);
-  const parsed = JSON.parse(jsonString);
   [
     'dev', 'mode', 'nlink', 'uid',
     'gid', 'rdev', 'blksize', 'ino', 'size', 'blocks',
@@ -91,19 +89,15 @@ fs.stat(__filename, common.mustSucceed((s) => {
     assert.ok(k in s, `${k} should be in Stats`);
     assert.notStrictEqual(s[k], undefined, `${k} should not be undefined`);
     assert.notStrictEqual(s[k], null, `${k} should not be null`);
-    assert.notStrictEqual(parsed[k], undefined, `${k} should not be undefined`);
-    assert.notStrictEqual(parsed[k], null, `${k} should not be null`);
   });
   [
     'dev', 'mode', 'nlink', 'uid', 'gid', 'rdev', 'blksize', 'ino', 'size',
     'blocks', 'atimeMs', 'mtimeMs', 'ctimeMs', 'birthtimeMs',
   ].forEach((k) => {
     assert.strictEqual(typeof s[k], 'number', `${k} should be a number`);
-    assert.strictEqual(typeof parsed[k], 'number', `${k} should be a number`);
   });
   ['atime', 'mtime', 'ctime', 'birthtime'].forEach((k) => {
     assert.ok(s[k] instanceof Date, `${k} should be a Date`);
-    assert.strictEqual(typeof parsed[k], 'string', `${k} should be a string`);
   });
 }));