src: lazily load internalBinding('uv') and build the errmap lazily

This removes the `internalBinding('uv')` call from the normal
bootstrap for now, and avoids building `errmap` by default which
expands to a lot of calls into V8.

PR-URL: https://github.com/nodejs/node/pull/25143
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

2 files changed, 33 insertions, 11 deletions

diff --git a/lib/internal/errors.js b/lib/internal/errors.js
index 8be692ef57..dae7f8600d 100644
--- a/lib/internal/errors.js
+++ b/lib/internal/errors.js
@@ -15,11 +15,6 @@ const kInfo = Symbol('info');
 const messages = new Map();
 const codes = {};
 
-const {
-  errmap,
-  UV_EAI_NODATA,
-  UV_EAI_NONAME
-} = internalBinding('uv');
 const { kMaxLength } = internalBinding('buffer');
 const { defineProperty } = Object;
 
@@ -237,6 +232,24 @@ function getMessage(key, args) {
   return util.format.apply(null, args);
 }
 
+let uvBinding;
+
+function lazyUv() {
+  if (!uvBinding) {
+    uvBinding = internalBinding('uv');
+  }
+  return uvBinding;
+}
+
+function lazyErrmapGet(name) {
+  uvBinding = lazyUv();
+  if (!uvBinding.errmap) {
+    uvBinding.errmap = uvBinding.getErrorMap();
+  }
+  return uvBinding.errmap.get(name);
+}
+
+
 /**
  * This creates an error compatible with errors produced in the C++
  * function UVException using a context object with data assembled in C++.
@@ -247,7 +260,7 @@ function getMessage(key, args) {
  * @returns {Error}
  */
 function uvException(ctx) {
-  const [ code, uvmsg ] = errmap.get(ctx.errno);
+  const [ code, uvmsg ] = lazyErrmapGet(ctx.errno);
   let message = `${code}: ${ctx.message || uvmsg}, ${ctx.syscall}`;
 
   let path;
@@ -303,7 +316,7 @@ function uvException(ctx) {
  * @returns {Error}
  */
 function uvExceptionWithHostPort(err, syscall, address, port) {
-  const [ code, uvmsg ] = errmap.get(err);
+  const [ code, uvmsg ] = lazyErrmapGet(err);
   const message = `${syscall} ${code}: ${uvmsg}`;
   let details = '';
 
@@ -421,7 +434,7 @@ function dnsException(code, syscall, hostname) {
   if (typeof code === 'number') {
     // FIXME(bnoordhuis) Remove this backwards compatibility nonsense and pass
     // the true error to the user. ENOTFOUND is not even a proper POSIX error!
-    if (code === UV_EAI_NODATA || code === UV_EAI_NONAME) {
+    if (code === lazyUv().UV_EAI_NODATA || code === lazyUv().UV_EAI_NONAME) {
       code = 'ENOTFOUND'; // Fabricated error name.
     } else {
       code = lazyInternalUtil().getSystemErrorName(code);
diff --git a/lib/internal/util.js b/lib/internal/util.js
index 16c1e3370c..902375afdb 100644
--- a/lib/internal/util.js
+++ b/lib/internal/util.js
@@ -16,8 +16,6 @@ const {
   isNativeError
 } = require('internal/util/types');
 
-const { errmap } = internalBinding('uv');
-
 const noCrypto = !process.versions.openssl;
 
 const experimentalWarnings = new Set();
@@ -250,8 +248,19 @@ function getConstructorOf(obj) {
   return null;
 }
 
+let uvBinding;
+function lazyErrmapGet(name) {
+  if (!uvBinding) {
+    uvBinding = internalBinding('uv');
+  }
+  if (!uvBinding.errmap) {
+    uvBinding.errmap = uvBinding.getErrorMap();
+  }
+  return uvBinding.errmap.get(name);
+}
+
 function getSystemErrorName(err) {
-  const entry = errmap.get(err);
+  const entry = lazyErrmapGet(err);
   return entry ? entry[0] : `Unknown system error ${err}`;
 }