Add Dart_Null, Dart_True, and Dart_False.

runtime/vm/dart_api_impl.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "include/dart_api.h"
 
 #include "vm/bigint_operations.h"
 #include "vm/class_finalizer.h"
 #include "vm/compiler.h"
 #include "vm/dart.h"
@@ skipping 418 matching lines @@
       return Api::Error("An exception occurred when converting to string");
     }
   } else {
     // This is a VM internal object. Call the C++ method of printing.
     result = String::New(obj.ToCString());
   }
   return Api::NewLocalHandle(result);
 }
 
 
+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.
   const Object& obj = Object::Handle(Api::UnwrapHandle(object));
   return obj.IsNull();
 }
 
 
 DART_EXPORT bool Dart_IsClosure(Dart_Handle object) {
   Zone zone;  // Setup a VM zone as we are creating some handles.
@@ skipping 181 matching lines @@
     bigint ^= obj.raw();
     ASSERT(!BigintOperations::FitsIntoInt64(bigint));
 #endif
     *fits = false;
     return Api::Success();
   }
   return Api::Error("Object is not a Integer");
 }
 
 
+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.
   const Object& obj = Object::Handle(Api::UnwrapHandle(object));
   return obj.IsBool();
 }
 
 
 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:

 }
 
 
 DART_EXPORT Dart_Handle Dart_BooleanValue(Dart_Handle bool_object,
                                           bool* value) {

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

Instead of this function does it make sense to have a Dart_IsTrue and
Dart_IsFalse similar to the way we have Dart_IsNull?

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

Discussed offline.  Let's defer adding these until we figure out what the
error-checking should be?

   Zone zone;  // Setup a VM zone as we are creating some handles.
   HandleScope scope;  // Setup a VM handle scope.
   const Object& obj = Object::Handle(Api::UnwrapHandle(bool_object));
   if (obj.IsBool()) {
     Bool& bool_obj = Bool::Handle();
     bool_obj ^= obj.raw();
     *value = bool_obj.value();
     return Api::Success();
   }
   return Api::Error("Object is not a Boolean");
@@ skipping 847 matching lines @@
   ApiState* state = isolate->api_state();
   ASSERT(state != NULL);
   ApiLocalScope* scope = state->top_scope();
   ASSERT(scope != NULL);
   state->set_top_scope(scope->previous());  // Reset top scope to previous.
   delete scope;  // Free up the old scope which we have just exited.
 }
 
 
 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);
 }
 
 
 DART_EXPORT Dart_Handle Dart_MakeWeakPersistentHandle(Dart_Handle object) {
   UNIMPLEMENTED();
   return NULL;
 }
 
 
 DART_EXPORT Dart_Handle Dart_MakePersistentHandle(Dart_Handle object) {
@@ skipping 433 matching lines @@
 
 Dart_Handle Api::Error(const char* text) {
   Zone zone;  // Setup a VM zone as we are creating some handles.
   HandleScope scope;  // Setup a VM handle scope.
   const String& message = String::Handle(String::New(text));
   const Object& obj = Object::Handle(ApiFailure::New(message));
   return Api::NewLocalHandle(obj);
 }
 
 
+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);
   ApiState* state = isolate->api_state();
   ASSERT(state != NULL);
   ApiLocalScope* scope = state->top_scope();
   ASSERT(scope != NULL);
   return scope->zone().Allocate(size);
 }
 
 
 uword Api::Reallocate(uword ptr, intptr_t old_size, intptr_t new_size) {
   Isolate* isolate = Isolate::Current();
   ASSERT(isolate != NULL);
   ApiState* state = isolate->api_state();
   ASSERT(state != NULL);
   ApiLocalScope* scope = state->top_scope();
   ASSERT(scope != NULL);
   return scope->zone().Reallocate(ptr, old_size, new_size);
 }
 
 
 }  // namespace dart