fs: improve performance for sync stat() functions

PR-URL: #11522
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

Author: mscdex

benchmark/fs/bench-statSync.js

@@ -5,17 +5,35 @@ const fs = require('fs');
 
 const bench = common.createBenchmark(main, {
   n: [1e4],
-  kind: ['lstatSync', 'statSync']
+  kind: ['fstatSync', 'lstatSync', 'statSync']
 });
 
 
 function main(conf) {
   const n = conf.n >>> 0;
-  const fn = fs[conf.kind];
-
-  bench.start();
-  for (var i = 0; i < n; i++) {
-    fn(__filename);
+  var fn;
+  var i;
+  switch (conf.kind) {
+    case 'statSync':
+    case 'lstatSync':
+      fn = fs[conf.kind];
+      bench.start();
+      for (i = 0; i < n; i++) {
+        fn(__filename);
+      }
+      bench.end(n);
+      break;
+    case 'fstatSync':
+      fn = fs.fstatSync;
+      const fd = fs.openSync(__filename, 'r');
+      bench.start();
+      for (i = 0; i < n; i++) {
+        fn(fd);
+      }
+      bench.end(n);
+      fs.closeSync(fd);
+      break;
+    default:
+      throw new Error('Invalid kind argument');
   }
-  bench.end(n);
 }

lib/fs.js

@@ -132,7 +132,7 @@ function isFd(path) {
 }
 
 // Static method to set the stats properties on a Stats object.
-fs.Stats = function(
+function Stats(
     dev,
     mode,
     nlink,
@@ -161,7 +161,8 @@ fs.Stats = function(
   this.mtime = new Date(mtim_msec);
   this.ctime = new Date(ctim_msec);
   this.birthtime = new Date(birthtim_msec);
-};
+}
+fs.Stats = Stats;
 
 // Create a C++ binding to the function which creates a Stats object.
 binding.FSInitialize(fs.Stats);
@@ -263,7 +264,7 @@ fs.existsSync = function(path) {
   try {
     handleError((path = getPathFromURL(path)));
     nullCheck(path);
-    binding.stat(pathModule._makeLong(path));
+    binding.stat(pathModule._makeLong(path), statValues);
     return true;
   } catch (e) {
     return false;
@@ -938,20 +939,33 @@ fs.stat = function(path, callback) {
   binding.stat(pathModule._makeLong(path), req);
 };
 
+const statValues = new Float64Array(14);
+function statsFromValues() {
+  return new Stats(statValues[0], statValues[1], statValues[2], statValues[3],
+                   statValues[4], statValues[5],
+                   statValues[6] < 0 ? undefined : statValues[6], statValues[7],
+                   statValues[8], statValues[9] < 0 ? undefined : statValues[9],
+                   statValues[10], statValues[11], statValues[12],
+                   statValues[13]);
+}
+
 fs.fstatSync = function(fd) {
-  return binding.fstat(fd);
+  binding.fstat(fd, statValues);
+  return statsFromValues();
 };
 
 fs.lstatSync = function(path) {
   handleError((path = getPathFromURL(path)));
   nullCheck(path);
-  return binding.lstat(pathModule._makeLong(path));
+  binding.lstat(pathModule._makeLong(path), statValues);
+  return statsFromValues();
 };
 
 fs.statSync = function(path) {
   handleError((path = getPathFromURL(path)));
   nullCheck(path);
-  return binding.stat(pathModule._makeLong(path));
+  binding.stat(pathModule._makeLong(path), statValues);
+  return statsFromValues();
 };
 
 fs.readlink = function(path, options, callback) {

src/node_file.cc

@@ -27,8 +27,10 @@
 namespace node {
 
 using v8::Array;
+using v8::ArrayBuffer;
 using v8::Context;
 using v8::EscapableHandleScope;
+using v8::Float64Array;
 using v8::Function;
 using v8::FunctionCallbackInfo;
 using v8::FunctionTemplate;
@@ -528,6 +530,37 @@ Local<Value> BuildStatsObject(Environment* env, const uv_stat_t* s) {
   return handle_scope.Escape(stats);
 }
 
+void FillStatsArray(double* fields, const uv_stat_t* s) {
+  fields[0] = s->st_dev;
+  fields[1] = s->st_mode;
+  fields[2] = s->st_nlink;
+  fields[3] = s->st_uid;
+  fields[4] = s->st_gid;
+  fields[5] = s->st_rdev;
+#if defined(__POSIX__)
+  fields[6] = s->st_blksize;
+#else
+  fields[6] = -1;
+#endif
+  fields[7] = s->st_ino;
+  fields[8] = s->st_size;
+#if defined(__POSIX__)
+  fields[9] = s->st_blocks;
+#else
+  fields[9] = -1;
+#endif
+  // Dates.
+#define X(idx, name)                                                          \
+  fields[idx] = (static_cast<double>(s->st_##name.tv_sec) * 1000) +           \
+                (static_cast<double>(s->st_##name.tv_nsec / 1000000));        \
+
+  X(10, atim)
+  X(11, mtim)
+  X(12, ctim)
+  X(13, birthtim)
+#undef X
+}
+
 // Used to speed up module loading.  Returns the contents of the file as
 // a string or undefined when the file cannot be opened.  The speedup
 // comes from not creating Error objects on failure.
@@ -612,12 +645,15 @@ static void Stat(const FunctionCallbackInfo<Value>& args) {
   BufferValue path(env->isolate(), args[0]);
   ASSERT_PATH(path)
 
-  if (args[1]->IsObject()) {
-    ASYNC_CALL(stat, args[1], UTF8, *path)
-  } else {
+  if (args[1]->IsFloat64Array()) {
+    Local<Float64Array> array = args[1].As<Float64Array>();
+    CHECK_EQ(array->Length(), 14);
+    Local<ArrayBuffer> ab = array->Buffer();
+    double* fields = static_cast<double*>(ab->GetContents().Data());
     SYNC_CALL(stat, *path, *path)
-    args.GetReturnValue().Set(
-        BuildStatsObject(env, static_cast<const uv_stat_t*>(SYNC_REQ.ptr)));
+    FillStatsArray(fields, static_cast<const uv_stat_t*>(SYNC_REQ.ptr));
+  } else if (args[1]->IsObject()) {
+    ASYNC_CALL(stat, args[1], UTF8, *path)
   }
 }
 
@@ -630,12 +666,15 @@ static void LStat(const FunctionCallbackInfo<Value>& args) {
   BufferValue path(env->isolate(), args[0]);
   ASSERT_PATH(path)
 
-  if (args[1]->IsObject()) {
-    ASYNC_CALL(lstat, args[1], UTF8, *path)
-  } else {
+  if (args[1]->IsFloat64Array()) {
+    Local<Float64Array> array = args[1].As<Float64Array>();
+    CHECK_EQ(array->Length(), 14);
+    Local<ArrayBuffer> ab = array->Buffer();
+    double* fields = static_cast<double*>(ab->GetContents().Data());
     SYNC_CALL(lstat, *path, *path)
-    args.GetReturnValue().Set(
-        BuildStatsObject(env, static_cast<const uv_stat_t*>(SYNC_REQ.ptr)));
+    FillStatsArray(fields, static_cast<const uv_stat_t*>(SYNC_REQ.ptr));
+  } else if (args[1]->IsObject()) {
+    ASYNC_CALL(lstat, args[1], UTF8, *path)
   }
 }
 
@@ -649,12 +688,15 @@ static void FStat(const FunctionCallbackInfo<Value>& args) {
 
   int fd = args[0]->Int32Value();
 
-  if (args[1]->IsObject()) {
-    ASYNC_CALL(fstat, args[1], UTF8, fd)
-  } else {
+  if (args[1]->IsFloat64Array()) {
+    Local<Float64Array> array = args[1].As<Float64Array>();
+    CHECK_EQ(array->Length(), 14);
+    Local<ArrayBuffer> ab = array->Buffer();
+    double* fields = static_cast<double*>(ab->GetContents().Data());
     SYNC_CALL(fstat, 0, fd)
-    args.GetReturnValue().Set(
-        BuildStatsObject(env, static_cast<const uv_stat_t*>(SYNC_REQ.ptr)));
+    FillStatsArray(fields, static_cast<const uv_stat_t*>(SYNC_REQ.ptr));
+  } else if (args[1]->IsObject()) {
+    ASYNC_CALL(fstat, args[1], UTF8, fd)
   }
 }