IDL: Enumerations support in dictionaries

Source/bindings/templates/dictionary_v8.cpp

Index: Source/bindings/templates/dictionary_v8.cpp
diff --git a/Source/bindings/templates/dictionary_v8.cpp b/Source/bindings/templates/dictionary_v8.cpp
index 82c6e9accf1d60a42ae7ed24b8c2baf9d2235c02..ca12139b8718deaf49a6dad3e39515d051c26cfe 100644
--- a/Source/bindings/templates/dictionary_v8.cpp
+++ b/Source/bindings/templates/dictionary_v8.cpp
@@ -13,7 +13,7 @@
 
 namespace blink {
 
-{{cpp_class}}* {{v8_class}}::toImpl(v8::Isolate* isolate, v8::Handle<v8::Value> v8Value)
+{{cpp_class}}* {{v8_class}}::toImpl(v8::Isolate* isolate, v8::Handle<v8::Value> v8Value, ExceptionState& exceptionState)

[Jens Widell, 2014/09/10 06:20:15]

This sort of conflicts with where I was going with
https://codereview.chromium.org/559553003/ ultimately; to have all functions
that throw exceptions via an ExceptionsState& argument throw all their
exceptions that way.

This function effectively throws exceptions directly via V8 sometimes, since it
calls into V8 via DictionaryHelper. Any exceptions thrown that way are ignored
by this code, but would probably be caught by a v8::TryCatch in the caller, and
then propagated.

This does not block this patch, though. Just saying. :-)

[bashi, 2014/09/10 07:21:04]

Thank you for the heads up. That's a fantastic plan! I'm also planning to
replace DictionaryHelper with a new class called PropertyBag, which will use
ExceptionStates to throw conversion exceptions.
https://codereview.chromium.org/534133002/

I'd like to land this at this moment, given that adding PropertyBag may take
time. But I'm willing to change the logic to follow your changes:)

[Jens Widell, 2014/09/10 08:31:11]

Yes, absolutely.

 {
     {{cpp_class}}* impl = {{cpp_class}}::create();
     // FIXME: Do not use Dictionary and DictionaryHelper
@@ -21,8 +21,17 @@ namespace blink {
     Dictionary dictionary(v8Value, isolate);
     {% for member in members %}
     {{member.cpp_type}} {{member.name}};
-    if (DictionaryHelper::getWithUndefinedOrNullCheck(dictionary, "{{member.name}}", {{member.name}}))
+    if (DictionaryHelper::getWithUndefinedOrNullCheck(dictionary, "{{member.name}}", {{member.name}})) {
+    {% if member.enum_validation_expression %}
+        String string = {{member.name}};
+        if ({{member.enum_validation_expression}})

[Jens Widell, 2014/09/10 06:20:15]

Rephrase this as

  if (!{{member.enum_validation_expression}}) {
    exceptionState.throwTypeError("member {{member.name}} ('" + string + "') is
not a valid enum value.");
    return NULL;
  }

and thus avoid duplicating the "impl->{{member.setter_name}}({{member.name}});"
line?

[bashi, 2014/09/10 07:21:04]

Great suggestion! Done.

+            impl->{{member.setter_name}}({{member.name}});
+        else
+            exceptionState.throwTypeError("member {{member.name}} ('" + string + "') is not a valid enum value.");
+    {% else %}
         impl->{{member.setter_name}}({{member.name}});
+    {% endif %}
+    }
     {% endfor %}
     return impl;
 }