Add utility functions for creating and accessing Dart_CObject structures

runtime/bin/dartutils.cc

Index: runtime/bin/dartutils.cc
diff --git a/runtime/bin/dartutils.cc b/runtime/bin/dartutils.cc
index cb0ae2bac099356a22c9d3b2b502fd65866c60cd..b472e7975946cb8c2b8f01a183560ba6053f06e6 100644
--- a/runtime/bin/dartutils.cc
+++ b/runtime/bin/dartutils.cc
@@ -252,9 +252,7 @@ const char* DartUtils::GetCanonicalPath(const char* reference_dir,
 
 bool DartUtils::PostNull(Dart_Port port_id) {
   // Post a message with just the null object.
-  Dart_CObject object;
-  object.type = Dart_CObject::kNull;
-  return Dart_PostCObject(port_id, &object);
+  return Dart_PostCObject(port_id, CObject::Null()->AsApiCObject());
 }
 
 
@@ -268,3 +266,89 @@ bool DartUtils::PostInt32(Dart_Port port_id, int32_t value) {
   object.value.as_int32 = value;
   return Dart_PostCObject(port_id, &object);
 }
+
+
+// Statically allocated Dart_CObject instances for immutable
+// objects. As these will be used by different threads the use of
+// these depends on the fact that the marking internally in the
+// Dart_CObject structure is not marking simple value objects.
+Dart_CObject CObject::api_null_ = { Dart_CObject::kNull , { 0 } };
+Dart_CObject CObject::api_true_ = { Dart_CObject::kBool , { true } };
+Dart_CObject CObject::api_false_ = { Dart_CObject::kBool, { false } };
+CObject CObject::null_ = CObject(&api_null_);
+CObject CObject::true_ = CObject(&api_true_);
+CObject CObject::false_ = CObject(&api_false_);
+
+
+CObject* CObject::Null() {
+  return &null_;
+}
+
+
+CObject* CObject::True() {
+  return &true_;
+}
+
+
+CObject* CObject::False() {
+  return &false_;
+}
+
+
+CObject* CObject::Bool(bool value) {
+  return value ? &true_ : &false_;
+}
+
+
+Dart_CObject* CObject::New(Dart_CObject::Type type, int additional_bytes) {
+  Dart_CObject* cobject = reinterpret_cast<Dart_CObject*>(
+      Dart_ScopeAllocate(sizeof(Dart_CObject) + additional_bytes));
+  cobject->type = type;
+  return cobject;
+}
+
+
+Dart_CObject* CObject::NewInt32(int32_t value) {
+  Dart_CObject* cobject = New(Dart_CObject::kInt32);
+  cobject->value.as_int32 = value;
+  return cobject;
+}
+
+
+Dart_CObject* CObject::NewInt64(int64_t value) {
+  Dart_CObject* cobject = New(Dart_CObject::kInt64);
+  cobject->value.as_int64 = value;
+  return cobject;
+}
+
+
+Dart_CObject* CObject::NewDouble(double value) {
+  Dart_CObject* cobject = New(Dart_CObject::kDouble);
+  cobject->value.as_double = value;
+  return cobject;
+}
+
+
+Dart_CObject* CObject::NewString(int length) {
+  Dart_CObject* cobject = New(Dart_CObject::kString, length + 1);
+  cobject->value.as_string = reinterpret_cast<char*>(cobject + 1);
+  return cobject;
+}
+
+
+Dart_CObject* CObject::NewString(const char* str) {
+  int length = strlen(str);
+  Dart_CObject* cobject = NewString(length);
+  memmove(cobject->value.as_string, str, length + 1);
+  return cobject;
+}
+
+
+Dart_CObject* CObject::NewArray(int length) {
+  Dart_CObject* cobject =
+      New(Dart_CObject::kArray, length * sizeof(Dart_CObject*));  // NOLINT
+  cobject->value.as_array.length = length;
+  cobject->value.as_array.values =
+      reinterpret_cast<Dart_CObject**>(cobject + 1);
+  return cobject;
+}