Speed up require(), phase 1 and 2

lib/module.js

@@ -6,6 +6,8 @@ const runInThisContext = require('vm').runInThisContext;
 const assert = require('assert').ok;
 const fs = require('fs');
 const path = require('path');
+const internalModuleReadFile = process.binding('fs').internalModuleReadFile;
+const internalModuleStat = process.binding('fs').internalModuleStat;
 
 
 // If obj.hasOwnProperty has been overridden, then calling
@@ -56,13 +58,6 @@ const debug = Module._debug;
 //   -> a.<ext>
 //   -> a/index.<ext>
 
-function statPath(path) {
-  try {
-    return fs.statSync(path);
-  } catch (ex) {}
-  return false;
-}
-
 // check if the directory is a package.json dir
 const packageMainCache = {};
 
@@ -71,10 +66,10 @@ function readPackage(requestPath) {
     return packageMainCache[requestPath];
   }
 
-  try {
-    var jsonPath = path.resolve(requestPath, 'package.json');
-    var json = fs.readFileSync(jsonPath, 'utf8');
-  } catch (e) {
+  var jsonPath = path.resolve(requestPath, 'package.json');
+  var json = internalModuleReadFile(jsonPath);
+
+  if (json === undefined) {
     return false;
   }
 
@@ -94,7 +89,7 @@ function tryPackage(requestPath, exts) {
   if (!pkg) return false;
 
   var filename = path.resolve(requestPath, pkg);
-  return tryFile(filename, null) || tryExtensions(filename, exts) ||
+  return tryFile(filename) || tryExtensions(filename, exts) ||
          tryExtensions(path.resolve(filename, 'index'), exts);
 }
 
@@ -104,18 +99,19 @@ function tryPackage(requestPath, exts) {
 Module._realpathCache = {};
 
 // check if the file exists and is not a directory
-function tryFile(requestPath, stats) {
-  stats = stats || statPath(requestPath);
-  if (stats && !stats.isDirectory()) {
-    return fs.realpathSync(requestPath, Module._realpathCache);
-  }
-  return false;
+function tryFile(requestPath) {
+  const rc = internalModuleStat(requestPath);
+  return rc === 0 && toRealPath(requestPath);
+}
+
+function toRealPath(requestPath) {
+  return fs.realpathSync(requestPath, Module._realpathCache);
 }
 
 // given a path check a the file exists with any of the set extensions
 function tryExtensions(p, exts) {
   for (var i = 0, EL = exts.length; i < EL; i++) {
-    var filename = tryFile(p + exts[i], null);
+    var filename = tryFile(p + exts[i]);
 
     if (filename) {
       return filename;
@@ -150,11 +146,10 @@ Module._findPath = function(request, paths) {
     var filename;
 
     if (!trailingSlash) {
-      var stats = statPath(basePath);
-      // try to join the request to the path
-      filename = tryFile(basePath, stats);
-
-      if (!filename && stats && stats.isDirectory()) {
+      const rc = internalModuleStat(basePath);
+      if (rc === 0) {  // File.
+        filename = toRealPath(basePath);
+      } else if (rc === 1) {  // Directory.
         filename = tryPackage(basePath, exts);
       }
 

src/node_file.cc

@@ -22,6 +22,8 @@
 # include <io.h>
 #endif
 
+#include <vector>
+
 namespace node {
 
 using v8::Array;
@@ -433,6 +435,70 @@ Local<Value> BuildStatsObject(Environment* env, const uv_stat_t* s) {
   return handle_scope.Escape(stats);
 }
 
+// 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.
+static void InternalModuleReadFile(const FunctionCallbackInfo<Value>& args) {
+  Environment* env = Environment::GetCurrent(args);
+
+  CHECK(args[0]->IsString());
+  node::Utf8Value path(env->isolate(), args[0]);
+
+  FILE* const stream = fopen(*path, "rb");
+  if (stream == nullptr) {
+    return;
+  }
+
+  std::vector<char> chars;
+  while (!ferror(stream)) {
+    const size_t kBlockSize = 32 << 10;
+    const size_t start = chars.size();
+    chars.resize(start + kBlockSize);
+    const size_t numchars = fread(&chars[start], 1, kBlockSize, stream);
+    if (numchars < kBlockSize) {
+      chars.resize(start + numchars);
+    }
+    if (numchars == 0) {
+      break;
+    }
+  }
+
+  CHECK_EQ(false, ferror(stream));
+  CHECK_EQ(0, fclose(stream));
+
+  size_t start = 0;
+  if (chars.size() >= 3 && 0 == memcmp(&chars[0], "\xEF\xBB\xBF", 3)) {
+    start = 3;  // Skip UTF-8 BOM.
+  }
+
+  Local<String> chars_string =
+      String::NewFromUtf8(env->isolate(),
+                          &chars[start],
+                          String::kNormalString,
+                          chars.size() - start);
+  args.GetReturnValue().Set(chars_string);
+}
+
+// Used to speed up module loading.  Returns 0 if the path refers to
+// a file, 1 when it's a directory or < 0 on error (usually -ENOENT.)
+// The speedup comes from not creating thousands of Stat and Error objects.
+static void InternalModuleStat(const FunctionCallbackInfo<Value>& args) {
+  Environment* env = Environment::GetCurrent(args);
+
+  CHECK(args[0]->IsString());
+  node::Utf8Value path(env->isolate(), args[0]);
+
+  uv_fs_t req;
+  int rc = uv_fs_stat(env->event_loop(), &req, *path, nullptr);
+  if (rc == 0) {
+    const uv_stat_t* const s = static_cast<const uv_stat_t*>(req.ptr);
+    rc = !!(s->st_mode & S_IFDIR);
+  }
+  uv_fs_req_cleanup(&req);
+
+  args.GetReturnValue().Set(rc);
+}
+
 static void Stat(const FunctionCallbackInfo<Value>& args) {
   Environment* env = Environment::GetCurrent(args);
 
@@ -1141,6 +1207,8 @@ void InitFs(Handle<Object> target,
   env->SetMethod(target, "rmdir", RMDir);
   env->SetMethod(target, "mkdir", MKDir);
   env->SetMethod(target, "readdir", ReadDir);
+  env->SetMethod(target, "internalModuleReadFile", InternalModuleReadFile);
+  env->SetMethod(target, "internalModuleStat", InternalModuleStat);
   env->SetMethod(target, "stat", Stat);
   env->SetMethod(target, "lstat", LStat);
   env->SetMethod(target, "fstat", FStat);