lib: speed up require(), phase 2

Replace calls to fs.readFileSync() with an internal variant that does
not create Error objects on failure and is a bit speedier in general.

A secondary benefit is that it improves start-up times in the debugger
because it no longer emits thousands of exception debug events.

On a medium-sized application[0], this commit and its predecessor reduce
start-up times from about 1.5s to 0.5s and reduce the number of start-up
exceptions from ~6100 to 32, half of them internal to the application.

[0] https://github.com/strongloop/loopback-sample-app

PR-URL: https://github.com/nodejs/io.js/pull/1801
Reviewed-By: Trevor Norris <trev.norris@gmail.com>

1 files changed, 5 insertions, 4 deletions

diff --git a/lib/module.js b/lib/module.js
index c9e4e2c785..65e44b60b1 100644
--- a/lib/module.js
+++ b/lib/module.js
@@ -6,6 +6,7 @@ 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;
 
 
@@ -65,10 +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;
   }