process: add process.features, remove process.useUV

Partially fixes #1385.

src/node.cc

@@ -2013,6 +2013,19 @@ static Handle<Array> EnvEnumerator(const AccessorInfo& info) {
 }
 
 
+static Handle<Object> GetFeatures() {
+  HandleScope scope;
+
+  Local<Object> obj = Object::New();
+  obj->Set(String::NewSymbol("uv"), Boolean::New(use_uv));
+  obj->Set(String::NewSymbol("ipv6"), True()); // TODO ping libuv
+  obj->Set(String::NewSymbol("tls"),
+      Boolean::New(get_builtin_module("crypto") != NULL));
+
+  return scope.Close(obj);
+}
+
+
 Handle<Object> SetupProcessObject(int argc, char *argv[]) {
   HandleScope scope;
 
@@ -2102,7 +2115,7 @@ Handle<Object> SetupProcessObject(int argc, char *argv[]) {
   process->Set(String::NewSymbol("ENV"), ENV);
 
   process->Set(String::NewSymbol("pid"), Integer::New(getpid()));
-  process->Set(String::NewSymbol("useUV"), use_uv ? True() : False());
+  process->Set(String::NewSymbol("features"), GetFeatures());
 
   // -e, --eval
   if (eval_string) {

src/node.js

@@ -31,7 +31,7 @@
 
   function startup() {
 
-    if (process.env.NODE_USE_UV == '1') process.useUV = true;
+    if (process.env.NODE_USE_UV == '1') process.features.uv = true;
 
     EventEmitter = NativeModule.require('events').EventEmitter;
     process.__proto__ = EventEmitter.prototype;
@@ -389,13 +389,13 @@
   function translateId(id) {
     switch (id) {
       case 'net':
-        return process.useUV ? 'net_uv' : 'net_legacy';
+        return process.features.uv ? 'net_uv' : 'net_legacy';
 
       case 'timers':
-        return process.useUV ? 'timers_uv' : 'timers_legacy';
+        return process.features.uv ? 'timers_uv' : 'timers_legacy';
 
       case 'dns':
-        return process.useUV ? 'dns_uv' : 'dns_legacy';
+        return process.features.uv ? 'dns_uv' : 'dns_legacy';
 
       default:
         return id;

test/internet/test-dns.js

@@ -25,7 +25,7 @@ var assert = require('assert');
     isIP = net.isIP,
     isIPv4 = net.isIPv4,
     isIPv6 = net.isIPv6,
-    uv = process.useUV;
+    uv = process.features.uv;
 
 var expected = 0,
     completed = 0,