Enable the WebIDL [Exposed] annotation on an interface's members.

Source/bindings/scripts/v8_utilities.py

 # Copyright (C) 2013 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 # copyright notice, this list of conditions and the following disclaimer
@@ skipping 207 matching lines @@
 
 # [DeprecateAs]
 def deprecate_as(member):
     extended_attributes = member.extended_attributes
     if 'DeprecateAs' not in extended_attributes:
         return None
     includes.add('core/frame/UseCounter.h')
     return extended_attributes['DeprecateAs']
 
 
+# [Exposed]
+def exposed(definition_or_member, interface):
+    extended_attributes = definition_or_member.extended_attributes
+    if 'Exposed' not in extended_attributes:
+        return None
+
+    # FIXME: [Exposed] is an extended attribute, the value of which should be parsed
+    # as |ExtendedAttributeIdentList| per the WebIDL parsing rules.

[Peter Beverloo, 2014/07/29 17:40:26]

Note: This was resolved 12 hours ago, and hasn't been implemented in Blink yet.

https://github.com/heycam/webidl/commit/68ebd7772eb5b4b2e10bd8bdee56145c77e318cf

+    exposure_set = set(extended_attributes['Exposed'].split('&'))

[bashi, 2014/07/30 00:34:34]

extended_attributes['Exposed'].split('[|&]') ?

I understand that the grammar of value list has changed, but we might want to
add a helper function for this.

[Peter Beverloo, 2014/07/30 14:48:15]

I added |sorted_extended_attribute_set| for the general case, and a
specialization for the exposed attribute as we also have to expand some values
(Worker = DedicatedWorker&SharedWorker&ServiceWorker).

+    interface_exposure_set = ('Window')  # Default value

[Jens Widell, 2014/07/29 18:24:29]

This ought to be ['Window'] or ('Window',). You're setting the variable to a
plain string here.

[Peter Beverloo, 2014/07/30 14:48:15]

Heh, thanks! Done

+
+    interface_extended_attributes = interface.extended_attributes
+    if 'Exposed' in interface_extended_attributes:
+        interface_exposure_set = interface_extended_attributes['Exposed'].split('&')
+
+    # Methods must not be exposed to a broader scope than their interface.
+    if not exposure_set.issubset(interface_exposure_set):
+        raise Exception('Interface members\' exposure sets must be a subset of the interface\'s.')
+
+    exposure_checks = []
+    for environment in exposure_set:
+        exposure_checks.append('context->is%s()' % environment)

[Peter Beverloo, 2014/07/29 17:40:26]

Do we have a canonical way of checking what kind of environment |context| (EC)
is? There are the isDocument and isWorkerGlobalScope checks, but these don't
have the granularity of different kinds of workers.

[haraken, 2014/07/29 20:13:10]

As far as I know, we currently don't have such methods. Probably it's worth
introducing them.

[Peter Beverloo, 2014/07/30 14:48:15]

Done.

+
+    return ' || '.join(exposure_checks)

[Peter Beverloo, 2014/07/29 17:40:26]

Is this the correct layer to join the checks together? I couldn't find much
precedence for this in the templates.

[Jens Widell, 2014/07/29 18:24:29]

You ought to sort somehow here, otherwise code generation could vary randomly.

Or you could keep exposure_set a list and convert temporarily to a set when used
as such.

[Peter Beverloo, 2014/07/30 14:48:15]

Done.

+
+
 # [GarbageCollected], [WillBeGarbageCollected]
 def gc_type(definition):
     extended_attributes = definition.extended_attributes
     if 'GarbageCollected' in extended_attributes:
         return 'GarbageCollectedObject'
     elif 'WillBeGarbageCollected' in extended_attributes:
         return 'WillBeGarbageCollectedObject'
     return 'RefCountedObject'
 
 
@@ skipping 29 matching lines @@
 
     The returned function checks if a method/attribute is enabled.
     Given extended attribute RuntimeEnabled=FeatureName, return:
         RuntimeEnabledFeatures::{featureName}Enabled
     """
     extended_attributes = definition_or_member.extended_attributes
     if 'RuntimeEnabled' not in extended_attributes:
         return None
     feature_name = extended_attributes['RuntimeEnabled']
     return 'RuntimeEnabledFeatures::%sEnabled' % uncapitalize(feature_name)