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 56 matching lines @@
     return any(extended_attribute in definition_or_member.extended_attributes
                for extended_attribute in extended_attribute_list)
 
 
 def has_extended_attribute_value(definition_or_member, name, value):
     extended_attributes = definition_or_member.extended_attributes
     return (name in extended_attributes and
             extended_attribute_value_contains(extended_attributes[name], value))
 
 
+def sorted_extended_attribute_list(definition_or_member, name):
+    extended_attributes = definition_or_member.extended_attributes
+    if name not in extended_attributes:
+        return []
+
+    attribute_values = re.split('[|&]', extended_attributes[name])
+    return sorted(attribute_values)
+
+
 ################################################################################
 # String handling
 ################################################################################
 
 def capitalize(name):
     """Capitalize first letter or initial acronym (used in setter names)."""
     for acronym in ACRONYMS:
         if name.startswith(acronym.lower()):
             return name.replace(acronym.lower(), acronym)
     return name[0].upper() + name[1:]
@@ skipping 131 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]
+EXPOSED_EXECUTION_CONTEXT_METHOD = {
+    'DedicatedWorker': 'isDedicatedWorkerGlobalScope',
+    'ServiceWorker': 'isServiceWorkerGlobalScope',
+    'SharedWorker': 'isSharedWorkerGlobalScope',
+    'Window': 'isDocument',
+    'Worker': 'isWorkerGlobalScope',
+}
+
+def exposed(definition_or_member, interface):
+    extended_attributes = definition_or_member.extended_attributes

[Jens Widell, 2014/07/30 16:48:45]

This local is only used once, on the line below, and is thus rather unnecessary.
And the check below could be done on 'exposure_list' instead:

  if not exposure_list:
    return None

[Peter Beverloo, 2014/07/31 19:02:21]

Done.

+    if 'Exposed' not in extended_attributes:
+        return None
+
+    exposure_list = sorted_extended_attribute_list(definition_or_member, 'Exposed')

[Jens Widell, 2014/07/30 16:48:45]

I think you could have stuck with 'exposure_set' here; it's still logically a
set of something, even if we use a Python list to represent it.

The suffix switch indicates that the suffix was actually just an explicit record
of the type of the stored value, and such are rarely useful IMO, in particular
not for something with a scope this limited.

We could also just call it 'exposure'.

This comment could also just be considered as noise. :-)

[Peter Beverloo, 2014/07/31 19:02:21]

I'm in dubio. It would indeed describe the contents accurately (a sorted set),
but it could cause some confusion since the Python data type in fact is a list.

Let's go with following the contents -- thanks!

+    interface_exposure_list = expanded_exposure_list_for_interface(interface)
+
+    # Methods must not be exposed to a broader scope than their interface.
+    if not set(exposure_list).issubset(interface_exposure_list):
+        raise Exception('Interface members\' exposure sets must be a subset of the interface\'s.')

[haraken, 2014/07/30 16:32:03]

Nit: We normally use ValueError instead of Exception.

[Peter Beverloo, 2014/07/31 19:02:22]

Done.

+
+    exposure_checks = []
+    for environment in exposure_list:
+        # Methods must be exposed on one of the scopes known to Blink.
+        if environment not in EXPOSED_EXECUTION_CONTEXT_METHOD:
+            raise Exception('Values for the [Exposed] annotation must reflect to a valid exposure scope.')

[haraken, 2014/07/30 16:32:03]

Ditto.

[Peter Beverloo, 2014/07/31 19:02:22]

Done.

+
+        exposure_checks.append('context->%s()' % EXPOSED_EXECUTION_CONTEXT_METHOD[environment])
+
+    return ' || '.join(exposure_checks)
+
+
+def expanded_exposure_list_for_interface(interface):
+    exposure_list = sorted_extended_attribute_list(interface, 'Exposed')
+
+    # "Worker" is an aggregation for the different kinds of workers.
+    if 'Worker' in exposure_list:
+        exposure_list.extend(('DedicatedWorker', 'SharedWorker', 'ServiceWorker'))
+
+    return sorted(set(exposure_list))
+
+
 # [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)