module: fix stat cache & simpler shebang

lib/internal/modules/cjs/helpers.js

@@ -5,25 +5,13 @@ const path = require('path');
 const { pathToFileURL } = require('internal/url');
 const { URL } = require('url');
 
-const {
-  CHAR_LINE_FEED,
-  CHAR_CARRIAGE_RETURN,
-  CHAR_EXCLAMATION_MARK,
-  CHAR_HASH,
-} = require('internal/constants');
-
 // Invoke with makeRequireFunction(module) where |module| is the Module object
 // to use as the context for the require() function.
 function makeRequireFunction(mod) {
   const Module = mod.constructor;
 
   function require(path) {
-    try {
-      exports.requireDepth += 1;
-      return mod.require(path);
-    } finally {
-      exports.requireDepth -= 1;
-    }
+    return mod.require(path);
   }
 
   function resolve(request, options) {
@@ -67,31 +55,17 @@ function stripBOM(content) {
  */
 function stripShebang(content) {
   // Remove shebang
-  var contLen = content.length;
-  if (contLen >= 2) {
-    if (content.charCodeAt(0) === CHAR_HASH &&
-        content.charCodeAt(1) === CHAR_EXCLAMATION_MARK) {
-      if (contLen === 2) {
-        // Exact match
-        content = '';
-      } else {
-        // Find end of shebang line and slice it off
-        var i = 2;
-        for (; i < contLen; ++i) {
-          var code = content.charCodeAt(i);
-          if (code === CHAR_LINE_FEED || code === CHAR_CARRIAGE_RETURN)
-            break;
-        }
-        if (i === contLen)
-          content = '';
-        else {
-          // Note that this actually includes the newline character(s) in the
-          // new output. This duplicates the behavior of the regular expression
-          // that was previously used to replace the shebang line
-          content = content.slice(i);
-        }
-      }
-    }
+  if (content.charAt(0) === '#' && content.charAt(1) === '!') {
+    // Find end of shebang line and slice it off
+    let index = content.indexOf('\n', 2);
+    if (index === -1)
+      return '';
+    if (content.charAt(index - 1) === '\r')
+      index--;
+    // Note that this actually includes the newline character(s) in the
+    // new output. This duplicates the behavior of the regular expression
+    // that was previously used to replace the shebang line
+    content = content.slice(index);
   }
   return content;
 }
@@ -160,7 +134,6 @@ module.exports = exports = {
   builtinLibs,
   makeRequireFunction,
   normalizeReferrerURL,
-  requireDepth: 0,
   stripBOM,
   stripShebang
 };

lib/internal/modules/cjs/loader.js

@@ -37,7 +37,6 @@ const { safeGetenv } = internalBinding('credentials');
 const {
   makeRequireFunction,
   normalizeReferrerURL,
-  requireDepth,
   stripBOM,
   stripShebang
 } = require('internal/modules/cjs/helpers');
@@ -85,18 +84,17 @@ const {
 
 const isWindows = process.platform === 'win32';
 
+let requireDepth = 0;
+let statCache = new Map();
 function stat(filename) {
   filename = path.toNamespacedPath(filename);
-  const cache = stat.cache;
-  if (cache !== null) {
-    const result = cache.get(filename);
-    if (result !== undefined) return result;
-  }
-  const result = internalModuleStat(filename);
-  if (cache !== null) cache.set(filename, result);
+  if (statCache === null) statCache = new Map();
+  let result = statCache.get(filename);
+  if (result !== undefined) return result;
+  result = internalModuleStat(filename);
+  statCache.set(filename, result);
   return result;
 }
-stat.cache = null;
 
 function updateChildren(parent, child, scan) {
   var children = parent && parent.children;
@@ -710,7 +708,12 @@ Module.prototype.require = function(id) {
     throw new ERR_INVALID_ARG_VALUE('id', id,
                                     'must be a non-empty string');
   }
-  return Module._load(id, this, /* isMain */ false);
+  requireDepth++;
+  try {
+    return Module._load(id, this, /* isMain */ false);
+  } finally {
+    requireDepth--;
+  }
 };
 
 
@@ -793,8 +796,6 @@ Module.prototype._compile = function(content, filename) {
   }
   var dirname = path.dirname(filename);
   var require = makeRequireFunction(this);
-  var depth = requireDepth;
-  if (depth === 0) stat.cache = new Map();
   var result;
   var exports = this.exports;
   var thisValue = exports;
@@ -806,7 +807,7 @@ Module.prototype._compile = function(content, filename) {
     result = compiledWrapper.call(thisValue, exports, require, module,
                                   filename, dirname);
   }
-  if (depth === 0) stat.cache = null;
+  if (requireDepth === 0) statCache = null;
   return result;
 };