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_set(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):
+    exposure_set = sorted_extended_attribute_set(definition_or_member, 'Exposed')
+    if not exposure_set:
+        return None
+
+    interface_exposure_set = expanded_exposure_set_for_interface(interface)
+
+    # Methods must not be exposed to a broader scope than their interface.
+    if not set(exposure_set).issubset(interface_exposure_set):
+        raise ValueError('Interface members\' exposure sets must be a subset of the interface\'s.')
+
+    exposure_checks = []
+    for environment in exposure_set:
+        # Methods must be exposed on one of the scopes known to Blink.
+        if environment not in EXPOSED_EXECUTION_CONTEXT_METHOD:
+            raise ValueError('Values for the [Exposed] annotation must reflect to a valid exposure scope.')
+
+        exposure_checks.append('context->%s()' % EXPOSED_EXECUTION_CONTEXT_METHOD[environment])
+
+    return ' || '.join(exposure_checks)
+
+
+def expanded_exposure_set_for_interface(interface):
+    exposure_set = sorted_extended_attribute_set(interface, 'Exposed')
+
+    # "Worker" is an aggregation for the different kinds of workers.
+    if 'Worker' in exposure_set:
+        exposure_set.extend(('DedicatedWorker', 'SharedWorker', 'ServiceWorker'))
+
+    return sorted(set(exposure_set))
+
+
 # [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)