Add native extensions for the Dart shell to mac and windows

runtime/bin/test_extension.cc

 // Copyright (c) 2012, 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 <string.h>
 
-#include "../include/dart_api.h"
+#include "include/dart_api.h"
 
-#define EXPORT_SYMBOL __attribute__ ((visibility ("default")))
+DART_EXTERN_C Dart_NativeFunction ResolveName(Dart_Handle name, int argc);
 
-extern "C" Dart_NativeFunction ResolveName(Dart_Handle name, int argc);
+DART_EXPORT Dart_Handle test_extension_Init(
+    Dart_Handle parent_library) {
+  if (Dart_IsError(parent_library)) {
+    return parent_library;

[Bill Hesse, 2012/03/06 15:04:07]

Reformat to longer lines.

+  }
 
-extern "C" EXPORT_SYMBOL Dart_Handle test_extension_Init(Dart_Handle library) {
-  if (Dart_IsError(library)) return library;
-  Dart_Handle check_return = Dart_SetNativeResolver(library, ResolveName);
+  Dart_Handle check_return =
+      Dart_SetNativeResolver(parent_library, ResolveName);
   if (Dart_IsError(check_return)) return check_return;
-  return Dart_Null();
+
+  return parent_library;
 }
 
-extern "C" void IfNull(Dart_NativeArguments arguments) {
+DART_EXTERN_C void IfNull(Dart_NativeArguments arguments) {

[Søren Gjesse, 2012/03/07 06:58:31]

Should we add an additional macro DART_NATIVE (or something like that) in place
of DART_EXTERN_C for the extension writer to use?

   Dart_Handle object = Dart_GetNativeArgument(arguments, 0);
+
   if (Dart_IsNull(object)) {
     Dart_SetReturnValue(arguments, Dart_GetNativeArgument(arguments, 1));
   } else {
     Dart_SetReturnValue(arguments, object);
   }
 }
 
-extern "C" Dart_NativeFunction ResolveName(Dart_Handle name, int argc) {
+DART_EXTERN_C Dart_NativeFunction ResolveName(Dart_Handle name, int argc) {

[Ivan Posva, 2012/03/07 07:22:51]

Can you please explain why these need to be 'extern "C"'? All the registered
callback can be mangled all you want, as they are never looked up by name.

   assert(Dart_IsString8(name));
   const char* cname;
   Dart_Handle check_error;
 
   check_error = Dart_StringToCString(name, &cname);
   if (Dart_IsError(check_error)) return NULL;
-  if (!strcmp("Cat_IfNull", cname) && argc == 2) {
+  if (!strcmp("TestExtension_IfNull", cname) && argc == 2) {
     return IfNull;
   }
   return NULL;
 }