fs: add *timeNs properties to BigInt Stats objects

- Extend the aliased buffer for stats objects to contain
  the entire time spec (seconds and nanoseconds) for the time
  values instead of calculating the milliseconds in C++ and
  lose precision there.
- Calculate the nanosecond-precision time values in JS and expose
  them in BigInt Stats objects as `*timeNs`. The
  millisecond-precision values are now calculated from the
  nanosecond-precision values.

PR-URL: https://github.com/nodejs/node/pull/21387
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>

2 files changed, 33 insertions, 5 deletions

diff --git a/test/parallel/test-fs-stat-bigint.js b/test/parallel/test-fs-stat-bigint.js
index d004112680..998ddb289d 100644
--- a/test/parallel/test-fs-stat-bigint.js
+++ b/test/parallel/test-fs-stat-bigint.js
@@ -59,6 +59,26 @@ function verifyStats(bigintStats, numStats) {
         bigintStats.isSymbolicLink(),
         numStats.isSymbolicLink()
       );
+    } else if (key.endsWith('Ms')) {
+      const nsKey = key.replace('Ms', 'Ns');
+      const msFromBigInt = bigintStats[key];
+      const nsFromBigInt = bigintStats[nsKey];
+      const msFromBigIntNs = Number(nsFromBigInt / (10n ** 6n));
+      const msFromNum = numStats[key];
+      // The difference between the millisecond-precision values should be
+      // smaller than 2
+      assert(
+        Math.abs(msFromNum - Number(msFromBigInt)) < 2,
+        `Number version ${key} = ${msFromNum}, ` +
+        `BigInt version ${key} = ${msFromBigInt}n`);
+      // The difference between the millisecond-precision value and the
+      // nanosecond-precision value scaled down to milliseconds should be
+      // smaller than 2
+      assert(
+        Math.abs(msFromNum - Number(msFromBigIntNs)) < 2,
+        `Number version ${key} = ${msFromNum}, ` +
+        `BigInt version ${nsKey} = ${nsFromBigInt}n` +
+        ` = ${msFromBigIntNs}ms`);
     } else if (Number.isSafeInteger(val)) {
       assert.strictEqual(
         bigintStats[key], BigInt(val),
diff --git a/test/parallel/test-fs-watchfile-bigint.js b/test/parallel/test-fs-watchfile-bigint.js
index d5528bb2d3..500a0ef1f6 100644
--- a/test/parallel/test-fs-watchfile-bigint.js
+++ b/test/parallel/test-fs-watchfile-bigint.js
@@ -1,14 +1,18 @@
 'use strict';
+
+// Flags: --expose-internals
+
 const common = require('../common');
 
 const assert = require('assert');
+const { BigIntStats } = require('internal/fs/utils');
 const fs = require('fs');
 const path = require('path');
 
 const tmpdir = require('../common/tmpdir');
 
 const enoentFile = path.join(tmpdir.path, 'non-existent-file');
-const expectedStatObject = new fs.Stats(
+const expectedStatObject = new BigIntStats(
   0n,                                        // dev
   0n,                                        // mode
   0n,                                        // nlink
@@ -19,10 +23,14 @@ const expectedStatObject = new fs.Stats(
   0n,                                        // ino
   0n,                                        // size
   0n,                                        // blocks
-  0n,                                        // atim_msec
-  0n,                                        // mtim_msec
-  0n,                                        // ctim_msec
-  0n                                         // birthtim_msec
+  0n,                                        // atimeMs
+  0n,                                        // mtimeMs
+  0n,                                        // ctimeMs
+  0n,                                        // birthtimeMs
+  0n,                                        // atimeNs
+  0n,                                        // mtimeNs
+  0n,                                        // ctimeNs
+  0n                                         // birthtimeNs
 );
 
 tmpdir.refresh();