IO v2: Handle illegal arguments to socket writes

runtime/vm/dart_api_impl.cc

-// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2013, 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"
 #include "vm/dart_api_impl.h"
@@ skipping 2011 matching lines @@
         args.SetAt(2, value_obj);
         return Api::NewHandle(isolate, DartEntry::InvokeDynamic(function,
                                                                 args));
       }
     }
     return Api::NewError("Object does not implement the 'List' interface");
   }
 }
 
 
-// TODO(hpayer): value should always be smaller then 0xff. Add error handling.
 #define GET_LIST_ELEMENT_AS_BYTES(isolate, type, obj, native_array, offset,    \
                                   length)                                      \
   const type& array = type::Cast(obj);                                         \
   if (Utils::RangeCheck(offset, length, array.Length())) {                     \
     Object& element = Object::Handle(isolate);                                 \
     for (int i = 0; i < length; i++) {                                         \
       element = array.At(offset + i);                                          \
       if (!element.IsInteger()) {                                              \
-        return Api::NewError("%s expects the argument 'list' to be "           \
-                             "a List of int", CURRENT_FUNC);                   \
+      Dart_Handle argument_error_class =                                       \
+          Dart_GetClass(                                                       \
+              Dart_LookupLibrary(Dart_NewStringFromCString("dart:core")),      \
+                                 Dart_NewStringFromCString("ArgumentError"));  \
+      Dart_Handle args[1];                                                     \
+      args[0] = Dart_NewStringFromCString("List contains non-int elements");   \
+      Dart_Handle exception =                                                  \
+          Dart_New(argument_error_class, Dart_Null(), 1, args);                \
+        return Dart_ThrowException(exception);                                 \
       }                                                                        \
       const Integer& integer = Integer::Cast(element);                         \
       native_array[i] = static_cast<uint8_t>(integer.AsInt64Value() & 0xff);   \
       ASSERT(integer.AsInt64Value() <= 0xff);                                  \

[Mads Ager (google), 2013/01/31 07:53:30]

I think this is what the TODO was about? It seems easy to hit this ASSERT. We
should either document the truncating behavior and remove the assert or make
this check part of the argument error check above.

Related question: what happens if the integer is a bigint that does not fit in
an int64_t?

For now, maybe we should leave the error handling TODO in there listing these
issues?

[Søren Gjesse, 2013/01/31 12:12:01]

You are right. I just saw the clamping and thought that the TODO was no longer
valid. Added it back in.

     }                                                                          \
     return Api::Success(isolate);                                              \
   }                                                                            \
   return Api::NewError("Invalid length passed in to access array elements");   \
 
 
 DART_EXPORT Dart_Handle Dart_ListGetAsBytes(Dart_Handle list,
                                             intptr_t offset,
                                             uint8_t* native_array,
                                             intptr_t length) {
@@ skipping 2464 matching lines @@
   }
   {
     NoGCScope no_gc;
     RawObject* raw_obj = obj.raw();
     isolate->heap()->SetPeer(raw_obj, peer);
   }
   return Api::Success(isolate);
 }
 
 }  // namespace dart