Add Dart_Null, Dart_True, and Dart_False.

runtime/vm/dart_api_impl.cc

Index: runtime/vm/dart_api_impl.cc
===================================================================
--- runtime/vm/dart_api_impl.cc	(revision 1035)
+++ runtime/vm/dart_api_impl.cc	(working copy)
@@ -436,6 +436,11 @@
 }
 
 
+DART_EXPORT Dart_Handle Dart_Null() {
+  return Api::Null();
+}
+
+
 DART_EXPORT bool Dart_IsNull(Dart_Handle object) {
   Zone zone;  // Setup a VM zone as we are creating some handles.
   HandleScope scope;  // Setup a VM handle scope.
@@ -637,6 +642,16 @@
 }
 
 
+DART_EXPORT Dart_Handle Dart_True() {
+  return Api::True();
+}
+
+
+DART_EXPORT Dart_Handle Dart_False() {
+  return Api::False();
+}
+
+
 DART_EXPORT bool Dart_IsBoolean(Dart_Handle object) {
   Zone zone;  // Setup a VM zone as we are creating some handles.
   HandleScope scope;  // Setup a VM handle scope.
@@ -646,10 +661,7 @@
 
 
 DART_EXPORT Dart_Handle Dart_NewBoolean(bool value) {
-  Zone zone;  // Setup a VM zone as we are creating some handles.
-  HandleScope scope;  // Setup a VM handle scope.
-  const Bool& obj = Bool::Handle(Bool::Get(value));
-  return Api::NewLocalHandle(obj);
+  return value ? Api::True() : Api::False();

[turnidge, 2011/11/03 20:54:27]

How do you feel about this?  Does it violate expectation to be returning a
persistent handle here?  It is mostly transparent to the user.

[siva, 2011/11/03 21:45:25]

I think this is fine the only thing we may have to do is to protect ourselves
from somebody calling Dart_DeletePersistentHandle(...) on these handles (null,
true, false). 

Maybe delete is a nop when these handles are passed in.

On 2011/11/03 20:54:27, turnidge wrote:

[turnidge, 2011/11/04 00:03:17]

Okay.  Added code to protect against one of these handles getting deleted by
hijacking the "callback" field on the handle.

On 2011/11/03 21:45:25, asiva wrote:

 }
 
 
@@ -1522,14 +1534,16 @@
 
 
 DART_EXPORT Dart_Handle Dart_NewPersistentHandle(Dart_Handle object) {
+  Zone zone;  // Setup a VM zone as we are creating some handles.
+  HandleScope scope;  // Setup a VM handle scope.
   Isolate* isolate = Isolate::Current();
   ASSERT(isolate != NULL);
   ApiState* state = isolate->api_state();
   ASSERT(state != NULL);
-  LocalHandle* local_ref = Api::UnwrapAsLocalHandle(*state, object);
-  PersistentHandle* ref = state->persistent_handles().AllocateHandle();
-  ref->set_raw(*local_ref);
-  return reinterpret_cast<Dart_Handle>(ref);
+  const Object& old_ref = Object::Handle(Api::UnwrapHandle(object));
+  PersistentHandle* new_ref = state->persistent_handles().AllocateHandle();
+  new_ref->set_raw(old_ref);
+  return reinterpret_cast<Dart_Handle>(new_ref);
 }
 
 
@@ -1983,6 +1997,36 @@
 }
 
 
+Dart_Handle Api::Null() {
+  Isolate* isolate = Isolate::Current();
+  ASSERT(isolate != NULL);
+  ApiState* state = isolate->api_state();
+  ASSERT(state != NULL);
+  PersistentHandle* null_handle = state->Null();
+  return reinterpret_cast<Dart_Handle>(null_handle);
+}
+
+
+Dart_Handle Api::True() {
+  Isolate* isolate = Isolate::Current();
+  ASSERT(isolate != NULL);
+  ApiState* state = isolate->api_state();
+  ASSERT(state != NULL);
+  PersistentHandle* true_handle = state->True();
+  return reinterpret_cast<Dart_Handle>(true_handle);
+}
+
+
+Dart_Handle Api::False() {
+  Isolate* isolate = Isolate::Current();
+  ASSERT(isolate != NULL);
+  ApiState* state = isolate->api_state();
+  ASSERT(state != NULL);
+  PersistentHandle* false_handle = state->False();
+  return reinterpret_cast<Dart_Handle>(false_handle);
+}
+
+
 uword Api::Allocate(intptr_t size) {
   Isolate* isolate = Isolate::Current();
   ASSERT(isolate != NULL);