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>

1 files changed, 108 insertions, 55 deletions

diff --git a/lib/internal/fs/utils.js b/lib/internal/fs/utils.js
index 14abad81ec..6cd6f7aceb 100644
--- a/lib/internal/fs/utils.js
+++ b/lib/internal/fs/utils.js
@@ -1,6 +1,6 @@
 'use strict';
 
-const { Reflect } = primordials;
+const { Object, Reflect } = primordials;
 
 const { Buffer, kMaxLength } = require('buffer');
 const {
@@ -16,7 +16,8 @@ const {
 } = require('internal/errors');
 const {
   isUint8Array,
-  isDate
+  isDate,
+  isBigUint64Array
 } = require('internal/util/types');
 const { once } = require('internal/util');
 const { toPathIfFileURL } = require('internal/url');
@@ -230,27 +231,9 @@ function preprocessSymlinkDestination(path, type, linkPath) {
   }
 }
 
-function dateFromNumeric(num) {
-  return new Date(Number(num) + 0.5);
-}
-
 // Constructor for file stats.
-function Stats(
-  dev,
-  mode,
-  nlink,
-  uid,
-  gid,
-  rdev,
-  blksize,
-  ino,
-  size,
-  blocks,
-  atim_msec,
-  mtim_msec,
-  ctim_msec,
-  birthtim_msec
-) {
+function StatsBase(dev, mode, nlink, uid, gid, rdev, blksize,
+                   ino, size, blocks) {
   this.dev = dev;
   this.mode = mode;
   this.nlink = nlink;
@@ -261,63 +244,132 @@ function Stats(
   this.ino = ino;
   this.size = size;
   this.blocks = blocks;
-  this.atimeMs = atim_msec;
-  this.mtimeMs = mtim_msec;
-  this.ctimeMs = ctim_msec;
-  this.birthtimeMs = birthtim_msec;
-  this.atime = dateFromNumeric(atim_msec);
-  this.mtime = dateFromNumeric(mtim_msec);
-  this.ctime = dateFromNumeric(ctim_msec);
-  this.birthtime = dateFromNumeric(birthtim_msec);
 }
 
-Stats.prototype._checkModeProperty = function(property) {
-  if (isWindows && (property === S_IFIFO || property === S_IFBLK ||
-    property === S_IFSOCK)) {
-    return false;  // Some types are not available on Windows
-  }
-  if (typeof this.mode === 'bigint') {  // eslint-disable-line valid-typeof
-    return (this.mode & BigInt(S_IFMT)) === BigInt(property);
-  }
-  return (this.mode & S_IFMT) === property;
-};
-
-Stats.prototype.isDirectory = function() {
+StatsBase.prototype.isDirectory = function() {
   return this._checkModeProperty(S_IFDIR);
 };
 
-Stats.prototype.isFile = function() {
+StatsBase.prototype.isFile = function() {
   return this._checkModeProperty(S_IFREG);
 };
 
-Stats.prototype.isBlockDevice = function() {
+StatsBase.prototype.isBlockDevice = function() {
   return this._checkModeProperty(S_IFBLK);
 };
 
-Stats.prototype.isCharacterDevice = function() {
+StatsBase.prototype.isCharacterDevice = function() {
   return this._checkModeProperty(S_IFCHR);
 };
 
-Stats.prototype.isSymbolicLink = function() {
+StatsBase.prototype.isSymbolicLink = function() {
   return this._checkModeProperty(S_IFLNK);
 };
 
-Stats.prototype.isFIFO = function() {
+StatsBase.prototype.isFIFO = function() {
   return this._checkModeProperty(S_IFIFO);
 };
 
-Stats.prototype.isSocket = function() {
+StatsBase.prototype.isSocket = function() {
   return this._checkModeProperty(S_IFSOCK);
 };
 
+const kNsPerMsBigInt = 10n ** 6n;
+const kNsPerSecBigInt = 10n ** 9n;
+const kMsPerSec = 10 ** 3;
+const kNsPerMs = 10 ** 6;
+function msFromTimeSpec(sec, nsec) {
+  return sec * kMsPerSec + nsec / kNsPerMs;
+}
+
+function nsFromTimeSpecBigInt(sec, nsec) {
+  return sec * kNsPerSecBigInt + nsec;
+}
+
+function dateFromMs(ms) {
+  return new Date(Number(ms) + 0.5);
+}
+
+function BigIntStats(dev, mode, nlink, uid, gid, rdev, blksize,
+                     ino, size, blocks,
+                     atimeNs, mtimeNs, ctimeNs, birthtimeNs) {
+  StatsBase.call(this, dev, mode, nlink, uid, gid, rdev, blksize,
+                 ino, size, blocks);
+
+  this.atimeMs = atimeNs / kNsPerMsBigInt;
+  this.mtimeMs = mtimeNs / kNsPerMsBigInt;
+  this.ctimeMs = ctimeNs / kNsPerMsBigInt;
+  this.birthtimeMs = birthtimeNs / kNsPerMsBigInt;
+  this.atimeNs = atimeNs;
+  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);
+}
+
+Object.setPrototypeOf(BigIntStats.prototype, StatsBase.prototype);
+Object.setPrototypeOf(BigIntStats, StatsBase);
+
+BigIntStats.prototype._checkModeProperty = function(property) {
+  if (isWindows && (property === S_IFIFO || property === S_IFBLK ||
+    property === S_IFSOCK)) {
+    return false;  // Some types are not available on Windows
+  }
+  return (this.mode & BigInt(S_IFMT)) === BigInt(property);
+};
+
+function Stats(dev, mode, nlink, uid, gid, rdev, blksize,
+               ino, size, blocks,
+               atimeMs, mtimeMs, ctimeMs, birthtimeMs) {
+  StatsBase.call(this, dev, mode, nlink, uid, gid, rdev, blksize,
+                 ino, size, blocks);
+  this.atimeMs = atimeMs;
+  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);
+}
+
+Object.setPrototypeOf(Stats.prototype, StatsBase.prototype);
+Object.setPrototypeOf(Stats, StatsBase);
+
+Stats.prototype._checkModeProperty = function(property) {
+  if (isWindows && (property === S_IFIFO || property === S_IFBLK ||
+    property === S_IFSOCK)) {
+    return false;  // Some types are not available on Windows
+  }
+  return (this.mode & S_IFMT) === property;
+};
+
 function getStatsFromBinding(stats, offset = 0) {
-  return new Stats(stats[0 + offset], stats[1 + offset], stats[2 + offset],
-                   stats[3 + offset], stats[4 + offset], stats[5 + offset],
-                   stats[6 + offset],  // blksize
-                   stats[7 + offset], stats[8 + offset],
-                   stats[9 + offset],  // blocks
-                   stats[10 + offset], stats[11 + offset],
-                   stats[12 + offset], stats[13 + offset]);
+  if (isBigUint64Array(stats)) {
+    return new BigIntStats(
+      stats[0 + offset], stats[1 + offset], stats[2 + offset],
+      stats[3 + offset], stats[4 + offset], stats[5 + offset],
+      stats[6 + offset], stats[7 + offset], stats[8 + offset],
+      stats[9 + offset],
+      nsFromTimeSpecBigInt(stats[10 + offset], stats[11 + offset]),
+      nsFromTimeSpecBigInt(stats[12 + offset], stats[13 + offset]),
+      nsFromTimeSpecBigInt(stats[14 + offset], stats[15 + offset]),
+      nsFromTimeSpecBigInt(stats[16 + offset], stats[17 + offset])
+    );
+  }
+  return new Stats(
+    stats[0 + offset], stats[1 + offset], stats[2 + offset],
+    stats[3 + offset], stats[4 + offset], stats[5 + offset],
+    stats[6 + offset], stats[7 + offset], stats[8 + offset],
+    stats[9 + offset],
+    msFromTimeSpec(stats[10 + offset], stats[11 + offset]),
+    msFromTimeSpec(stats[12 + offset], stats[13 + offset]),
+    msFromTimeSpec(stats[14 + offset], stats[15 + offset]),
+    msFromTimeSpec(stats[16 + offset], stats[17 + offset])
+  );
 }
 
 function stringToFlags(flags) {
@@ -453,6 +505,7 @@ function warnOnNonPortableTemplate(template) {
 
 module.exports = {
   assertEncoding,
+  BigIntStats,  // for testing
   copyObject,
   Dirent,
   getDirents,