Modify the Weak Reference Set creation API to make it easier to create

runtime/vm/dart_api_impl.cc

Index: runtime/vm/dart_api_impl.cc
===================================================================
--- runtime/vm/dart_api_impl.cc	(revision 35211)
+++ runtime/vm/dart_api_impl.cc	(working copy)
@@ -93,6 +93,16 @@
 }
 
 
+WeakReferenceSetBuilder* ApiState::NewWeakReferenceSetBuilder() {
+  return new WeakReferenceSetBuilder(this);
+}
+
+
+void ApiState::DelayWeakReferenceSet(WeakReferenceSet* reference_set) {
+  WeakReferenceSet::Push(reference_set, &delayed_weak_reference_sets_);
+}
+
+
 Dart_Handle Api::InitNewHandle(Isolate* isolate, RawObject* raw) {
   LocalHandles* local_handles = Api::TopScope(isolate)->local_handles();
   ASSERT(local_handles != NULL);
@@ -742,39 +752,66 @@
 }
 
 
-DART_EXPORT Dart_Handle Dart_NewWeakReferenceSet(
-    Dart_WeakPersistentHandle* keys,
-    intptr_t num_keys,
-    Dart_WeakPersistentHandle* values,
-    intptr_t num_values) {
+DART_EXPORT Dart_WeakReferenceSetBuilder Dart_NewWeakReferenceSetBuilder() {
   Isolate* isolate = Isolate::Current();
   CHECK_ISOLATE(isolate);
   ApiState* state = isolate->api_state();
   ASSERT(state != NULL);
-  if (keys == NULL) {
-    RETURN_NULL_ERROR(keys);
+  return reinterpret_cast<Dart_WeakReferenceSetBuilder>(
+      state->NewWeakReferenceSetBuilder());
+}
+
+
+DART_EXPORT Dart_WeakReferenceSet Dart_NewWeakReferenceSet(
+    Dart_WeakReferenceSetBuilder set_builder,
+    Dart_WeakPersistentHandle key,
+    Dart_WeakPersistentHandle value) {
+  ASSERT(set_builder != NULL && key != NULL);
+  WeakReferenceSetBuilder* builder =
+      reinterpret_cast<WeakReferenceSetBuilder*>(set_builder);
+  ApiState* state = builder->api_state();
+  ASSERT(state == Isolate::Current()->api_state());
+  WeakReferenceSet* reference_set = builder->NewWeakReferenceSet();
+  reference_set->AppendKey(key);
+  if (value != NULL) {
+    reference_set->AppendValue(value);
   }
-  if (num_keys <= 0) {
-    return Api::NewError(
-        "%s expects argument 'num_keys' to be greater than 0.",
-        CURRENT_FUNC);
-  }
-  if (values == NULL) {
-    RETURN_NULL_ERROR(values);
-  }
-  if (num_values <= 0) {
-    return Api::NewError(
-        "%s expects argument 'num_values' to be greater than 0.",
-        CURRENT_FUNC);
-  }
+  state->DelayWeakReferenceSet(reference_set);
+  return reinterpret_cast<Dart_WeakReferenceSet>(reference_set);
+}
 
-  WeakReferenceSet* reference_set = new WeakReferenceSet(keys, num_keys,
-                                                         values, num_values);
-  state->DelayWeakReferenceSet(reference_set);
+
+DART_EXPORT Dart_Handle Dart_AppendToWeakReferenceSet(
+    Dart_WeakReferenceSet reference_set,
+    Dart_WeakPersistentHandle key,
+    Dart_WeakPersistentHandle value) {
+  ASSERT(reference_set != NULL);
+  WeakReferenceSet* set = reinterpret_cast<WeakReferenceSet*>(reference_set);
+  set->Append(key, value);
   return Api::Success();
 }
 
 
+DART_EXPORT Dart_Handle Dart_AppendKeyToWeakReferenceSet(
+    Dart_WeakReferenceSet reference_set,
+    Dart_WeakPersistentHandle key) {
+  ASSERT(reference_set != NULL);
+  WeakReferenceSet* set = reinterpret_cast<WeakReferenceSet*>(reference_set);
+  set->AppendKey(key);
+  return Api::Success();
+}
+
+
+DART_EXPORT Dart_Handle Dart_AppendValueToWeakReferenceSet(
+    Dart_WeakReferenceSet reference_set,
+    Dart_WeakPersistentHandle value) {
+  ASSERT(reference_set != NULL);
+  WeakReferenceSet* set = reinterpret_cast<WeakReferenceSet*>(reference_set);
+  set->AppendValue(value);
+  return Api::Success();
+}
+
+
 // --- Garbage Collection Callbacks --
 
 DART_EXPORT Dart_Handle Dart_SetGcCallbacks(