- Refactor the way X.fromEnvironment is implemented.

runtime/lib/integers.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 "vm/bootstrap_natives.h"
 
 #include "include/dart_api.h"
 #include "vm/bigint_operations.h"
 #include "vm/dart_entry.h"
 #include "vm/dart_api_impl.h"
@@ skipping 221 matching lines @@
 DEFINE_NATIVE_ENTRY(Integer_parse, 1) {
   GET_NON_NULL_NATIVE_ARGUMENT(String, value, arguments->NativeArgAt(0));
   return ParseInteger(value);
 }
 
 
 DEFINE_NATIVE_ENTRY(Integer_fromEnvironment, 3) {
   GET_NON_NULL_NATIVE_ARGUMENT(String, name, arguments->NativeArgAt(1));
   GET_NATIVE_ARGUMENT(Integer, default_value, arguments->NativeArgAt(2));
   // Call the embedder to supply us with the environment.
-  Api::Scope api_scope(isolate);
-  Dart_EnvironmentCallback callback = isolate->environment_callback();
-  if (callback != NULL) {
-    Dart_Handle response = callback(Api::NewHandle(isolate, name.raw()));
-    if (Dart_IsString(response)) {
-      const String& value = String::Cast(
-          Object::Handle(isolate, Api::UnwrapHandle(response)));
-      const Integer& result = Integer::Handle(ParseInteger(value));
-      if (!result.IsNull()) {
-        if (result.IsSmi()) return result.raw();
-        return result.CheckAndCanonicalize(NULL);
+  const String& env_value =
+      String::Handle(Api::CallEnvironmentCallback(isolate, name));
+  if (!env_value.IsNull()) {
+    const Integer& result = Integer::Handle(ParseInteger(env_value));
+    if (!result.IsNull()) {
+      if (result.IsSmi()) {
+        return result.raw();
       }
-    } else if (Dart_IsError(response)) {
-      const Object& error =
-          Object::Handle(isolate, Api::UnwrapHandle(response));
-      Exceptions::ThrowArgumentError(
-          String::Handle(
-              String::New(Error::Cast(error).ToErrorCString())));
-    } else  if (!Dart_IsNull(response)) {
-      Exceptions::ThrowArgumentError(
-          String::Handle(String::New("Illegal environment value")));
+      return result.CheckAndCanonicalize(NULL);
     }
   }
   return default_value.raw();
 }
 
 
 // Passing true for 'silent' prevents throwing JavascriptIntegerOverflow.
 static RawInteger* ShiftOperationHelper(Token::Kind kind,
                                         const Integer& value,
                                         const Smi& amount,
@@ skipping 172 matching lines @@
   // Use the preallocated out of memory exception to avoid calling
   // into dart code or allocating any code.
   const Instance& exception =
       Instance::Handle(isolate->object_store()->out_of_memory());
   Exceptions::Throw(isolate, exception);
   UNREACHABLE();
   return 0;
 }
 
 }  // namespace dart