IDL: Enumerations support in dictionaries

Source/bindings/templates/dictionary_v8.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file has been auto-generated by {{code_generator}}. DO NOT MODIFY!
 
 #include "config.h"
 #include "{{v8_class}}.h"
 
 {% for filename in cpp_includes if filename != '%s.h' % v8_class %}
 #include "{{filename}}"
 {% endfor %}
 
 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
     // https://crbug.com/321462
     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;
 }
 
 v8::Handle<v8::Value> toV8({{cpp_class}}* impl, v8::Handle<v8::Object> creationContext, v8::Isolate* isolate)
 {
     v8::Handle<v8::Object> v8Object = v8::Object::New(isolate);
     {% for member in members %}
     if (impl->{{member.has_method_name}}())
         v8Object->Set(v8String(isolate, "{{member.name}}"), {{member.cpp_value_to_v8_value}});
     {% if member.v8_default_value %}
     else
         v8Object->Set(v8String(isolate, "{{member.name}}"), {{member.v8_default_value}});
     {% endif %}
     {% endfor %}
     return v8Object;
 }
 
 } // namespace blink