Object.observe: use JSWeakMaps instead of raw ObjectHashTables in observation state

test/cctest/test-object-observe.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 12 matching lines @@
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include "v8.h"
 
 #include "cctest.h"
 
 using namespace v8;
+namespace i = v8::internal;
 
 namespace {
 // Need to create a new isolate when FLAG_harmony_observation is on.
 class HarmonyIsolate {
  public:
   HarmonyIsolate() {
     i::FLAG_harmony_observation = true;
     isolate_ = Isolate::New();
     isolate_->Enter();
   }
@@ skipping 347 matching lines @@
       "Object.unobserve(obj, observer);"
       "obj.foo = 44;");
   const RecordExpectation expected_records3[] = {
     { proto, "new", "bar", Handle<Value>() }
     // TODO(adamk): The below record should be emitted since proto is observed
     // and has been modified. Not clear if this happens in practice.
     // { proto, "updated", "foo", Number::New(43) }
   };
   EXPECT_RECORDS(CompileRun("records"), expected_records3);
 }
+
+
+static int NumberOfElements(i::Handle<i::JSWeakMap> map) {
+  return i::ObjectHashTable::cast(map->table())->NumberOfElements();
+}
+
+
+TEST(ObservationWeakMap) {
+  HarmonyIsolate isolate;
+  HandleScope scope;
+  LocalContext context;
+  CompileRun(
+      "var obj = {};"
+      "Object.observe(obj, function(){});"
+      "Object.getNotifier(obj);"
+      "obj = null;");
+  i::Handle<i::JSObject> observation_state = FACTORY->observation_state();
+  i::Handle<i::JSWeakMap> observerInfoMap =
+      i::Handle<i::JSWeakMap>::cast(
+          i::GetProperty(observation_state, "observerInfoMap"));
+  i::Handle<i::JSWeakMap> objectInfoMap =
+      i::Handle<i::JSWeakMap>::cast(
+          i::GetProperty(observation_state, "objectInfoMap"));
+  i::Handle<i::JSWeakMap> notifierTargetMap =
+      i::Handle<i::JSWeakMap>::cast(
+          i::GetProperty(observation_state, "notifierTargetMap"));
+  CHECK_EQ(1, NumberOfElements(observerInfoMap));
+  CHECK_EQ(1, NumberOfElements(objectInfoMap));
+  CHECK_EQ(1, NumberOfElements(notifierTargetMap));
+  HEAP->CollectAllGarbage(i::Heap::kNoGCFlags);
+  CHECK_EQ(0, NumberOfElements(observerInfoMap));
+  CHECK_EQ(0, NumberOfElements(objectInfoMap));
+  CHECK_EQ(0, NumberOfElements(notifierTargetMap));
+}