Introduce a flag to disable string operator +

runtime/lib/string.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 "vm/bootstrap_natives.h"
 
 #include "vm/exceptions.h"
 #include "vm/native_entry.h"
 #include "vm/object.h"
 
@@ skipping 99 matching lines @@
 
 
 DEFINE_NATIVE_ENTRY(String_concat, 2) {
   const String& receiver = String::CheckedHandle(arguments->At(0));
   GET_NATIVE_ARGUMENT(String, b, arguments->At(1));
   const String& result = String::Handle(String::Concat(receiver, b));
   arguments->SetReturn(result);
 }
 
 
+// TODO(hausner): Remove obsolete String_plus.
+DECLARE_FLAG(bool, allow_string_plus);

[Ivan Posva, 2012/04/11 12:03:57]

Usually we try to declare flags at the top of the file, but since this is
temporary I do like it better here as well.

+DEFINE_NATIVE_ENTRY(String_plus, 2) {
+  const String& receiver = String::CheckedHandle(arguments->At(0));
+  GET_NATIVE_ARGUMENT(String, b, arguments->At(1));
+  if (!FLAG_allow_string_plus) {
+    // Throw a noSuchMethod exception if operator + is not supported.
+    const String& func_name = String::Handle(String::New("+"));
+    const Array& func_args = Array::Handle(Array::New(1));
+    func_args.SetAt(0, b);
+    GrowableArray<const Object*> dart_arguments(3);
+    dart_arguments.Add(&receiver);
+    dart_arguments.Add(&func_name);
+    dart_arguments.Add(&func_args);
+    Exceptions::ThrowByType(Exceptions::kNoSuchMethod, dart_arguments);
+  }
+  const String& result = String::Handle(String::Concat(receiver, b));
+  arguments->SetReturn(result);
+}
+
+
 DEFINE_NATIVE_ENTRY(String_toLowerCase, 1) {
   const String& receiver = String::CheckedHandle(arguments->At(0));
   ASSERT(!receiver.IsNull());
   const String& result = String::Handle(String::ToLowerCase(receiver));
   arguments->SetReturn(result);
 }
 
 
 DEFINE_NATIVE_ENTRY(String_toUpperCase, 1) {
   const String& receiver = String::CheckedHandle(arguments->At(0));
@@ skipping 18 matching lines @@
       GrowableArray<const Object*> args;
       args.Add(&elem);
       Exceptions::ThrowByType(Exceptions::kIllegalArgument, args);
     }
   }
   const String& result = String::Handle(String::ConcatAll(strings));
   arguments->SetReturn(result);
 }
 
 }  // namespace dart