V8 API: Add a missing NULL check into Isolate::GetCurrentContext().

There is a missing NULL check for: "internal_isolate->context() != NULL".
Right now before calling this method one should call v8::Context::InContext()
first to perform this check, otherwise we may crash. But this static method
will do this check on the current isolate, which may not be the same as a given one.

BUG=249655
R=yurys@chromium.org,mvstanton@chromium.org

Review URL: https://codereview.chromium.org/16943006

Patch from Andrey Adaykin <aandrey@chromium.org>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15266 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/api.cc

@@ -6559,10 +6559,11 @@ CpuProfiler* Isolate::GetCpuProfiler() {
 
 v8::Local<v8::Context> Isolate::GetCurrentContext() {
   i::Isolate* internal_isolate = reinterpret_cast<i::Isolate*>(this);
-  i::Handle<i::Object> current = internal_isolate->native_context();
-  if (current.is_null()) return Local<Context>();
-  i::Handle<i::Context> context = i::Handle<i::Context>::cast(current);
-  return Utils::ToLocal(context);
+  i::Context* context = internal_isolate->context();
+  if (context == NULL) return Local<Context>();
+  i::Context* native_context = context->global_object()->native_context();
+  if (native_context == NULL) return Local<Context>();
+  return Utils::ToLocal(i::Handle<i::Context>(native_context));
 }
 
 

test/cctest/test-api.cc

@@ -14200,6 +14200,18 @@ static void GetCallingContextCallback(
 }
 
 
+THREADED_TEST(GetCurrentContextWhenNotInContext) {
+  i::Isolate* isolate = i::Isolate::Current();
+  CHECK(isolate != NULL);
+  CHECK(isolate->context() == NULL);
+  v8::Isolate* v8_isolate = reinterpret_cast<v8::Isolate*>(isolate);
+  v8::HandleScope scope(v8_isolate);
+  // The following should not crash, but return an empty handle.
+  v8::Local<v8::Context> current = v8_isolate->GetCurrentContext();
+  CHECK(current.IsEmpty());
+}
+
+
 THREADED_TEST(GetCallingContext) {
   v8::Isolate* isolate = v8::Isolate::GetCurrent();
   v8::HandleScope scope(isolate);