util: correctly inspect Map/Set Iterators

Previously, a MapIterator or SetIterator would
not be inspected properly. This change makes it possible
to inspect them by creating a Debug Mirror and previewing
the iterators to not consume the actual iterator that
we are trying to inspect.

This change also adds a node_util binding that uses
v8's Value::IsSetIterator and Value::IsMapIterator
to verify that the values passed in are actual iterators.

Fixes: https://github.com/nodejs/node/issues/3107
PR-URL: https://github.com/nodejs/node/pull/3119
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

1 files changed, 38 insertions, 0 deletions

diff --git a/src/node_util.cc b/src/node_util.cc
new file mode 100644
index 0000000000..cc86478e09
--- /dev/null
+++ b/src/node_util.cc
@@ -0,0 +1,38 @@
+#include "node.h"
+#include "v8.h"
+#include "env.h"
+#include "env-inl.h"
+
+namespace node {
+namespace util {
+
+using v8::Context;
+using v8::FunctionCallbackInfo;
+using v8::Local;
+using v8::Object;
+using v8::Value;
+
+static void IsMapIterator(const FunctionCallbackInfo<Value>& args) {
+  CHECK_EQ(1, args.Length());
+  args.GetReturnValue().Set(args[0]->IsMapIterator());
+}
+
+
+static void IsSetIterator(const FunctionCallbackInfo<Value>& args) {
+  CHECK_EQ(1, args.Length());
+  args.GetReturnValue().Set(args[0]->IsSetIterator());
+}
+
+
+void Initialize(Local<Object> target,
+                Local<Value> unused,
+                Local<Context> context) {
+  Environment* env = Environment::GetCurrent(context);
+  env->SetMethod(target, "isMapIterator", IsMapIterator);
+  env->SetMethod(target, "isSetIterator", IsSetIterator);
+}
+
+}  // namespace util
+}  // namespace node
+
+NODE_MODULE_CONTEXT_AWARE_BUILTIN(util, node::util::Initialize)