mojo::Serialize*_() calls now propogate/return validation errors.

mojo/public/cpp/bindings/lib/map_serialization.h

Index: mojo/public/cpp/bindings/lib/map_serialization.h
diff --git a/mojo/public/cpp/bindings/lib/map_serialization.h b/mojo/public/cpp/bindings/lib/map_serialization.h
index 8ef83b3a3a554947606e20eb0aa01beaa53d06a5..d5101f42fd1acfd58566796187627211f5df9c6d 100644
--- a/mojo/public/cpp/bindings/lib/map_serialization.h
+++ b/mojo/public/cpp/bindings/lib/map_serialization.h
@@ -128,7 +128,7 @@ template <typename MapKey,
           typename MapValue,
           typename DataKey,
           typename DataValue>
-inline void SerializeMap_(
+inline internal::ValidationError SerializeMap_(
     Map<MapKey, MapValue>* input,
     internal::Buffer* buf,
     internal::Map_Data<DataKey, DataValue>** output,
@@ -148,9 +148,14 @@ inline void SerializeMap_(
       const internal::ArrayValidateParams* key_validate_params =
           internal::MapKeyValidateParamsFactory<DataKey>::Get();
 
-      internal::ArraySerializer<MapKey, DataKey>::SerializeElements(
-          key_iter.begin(), input->size(), buf, result->keys.ptr,
-          key_validate_params);
+      {
+        auto retval =
+            internal::ArraySerializer<MapKey, DataKey>::SerializeElements(
+                key_iter.begin(), input->size(), buf, result->keys.ptr,
+                key_validate_params);
+        if (retval != internal::ValidationError::VALIDATION_ERROR_NONE)
+          return retval;

[viettrungluu, 2015/10/06 16:40:06]

Are you supposed to set *output in this case? (Ditto below.)

(What exactly is the contract for this function on error?)

[vardhan, 2015/10/06 22:57:14]

No, not in this case -- setting "*output = nullptr" needs to happen if the map
we're serializing |is_null()| (and is also nullable), in which case the
serialization is successful.

SerializeMap_ delegates almost all of its logic to serializing two arrays, where
the actual data will lie, so those errors are propogated back.  I can't see any
other validation-related errors here.

+      }
 
       // Now we try allocate an Array_Data for the values
       internal::Array_Data<DataValue>* values_data =
@@ -158,15 +163,21 @@ inline void SerializeMap_(
       if (values_data) {
         result->values.ptr = values_data;
         internal::MapValueIterator<MapKey, MapValue> value_iter(input);
-        internal::ArraySerializer<MapValue, DataValue>::SerializeElements(
-            value_iter.begin(), input->size(), buf, result->values.ptr,
-            value_validate_params);
+        {

[viettrungluu, 2015/10/06 16:40:06]

These braces seem redundant.

But more generally, I think you should restructure this function to be cleaner
(maybe with some helper functions).

The way errors are handled in this function seem bad.

[vardhan, 2015/10/06 22:57:14]

This way, I could reuse 'retval' as the name for the return value for keys and
values.  I thought it looked cleaner (and delineated which was serializing keys
and which was values).  But removing..
I removed the unnecessary '::New()' checking that flattened this function out a
bit more, PTAL.

There's not much happening here other than preparing the params for calling
|SerializeELements| and propogating any returned errors.. But i have no problem
doing it if you still think this version looks messy.

+          auto retval =
+              internal::ArraySerializer<MapValue, DataValue>::SerializeElements(
+                  value_iter.begin(), input->size(), buf, result->values.ptr,
+                  value_validate_params);
+          if (retval != internal::ValidationError::VALIDATION_ERROR_NONE)
+            return retval;
+        }
       }
     }
     *output = result;
   } else {
     *output = nullptr;
   }
+  return internal::ValidationError::VALIDATION_ERROR_NONE;
 }
 
 template <typename MapKey,