IDL: Generate union type containers

Source/bindings/scripts/v8_union.py

Index: Source/bindings/scripts/v8_union.py
diff --git a/Source/bindings/scripts/v8_union.py b/Source/bindings/scripts/v8_union.py
index 994deb70f1c801390f944db5192e12c31f6aeabd..fab726e59ebf04553547ce817cb35ad7512580e8 100644
--- a/Source/bindings/scripts/v8_union.py
+++ b/Source/bindings/scripts/v8_union.py
@@ -2,15 +2,90 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import v8_utilities
 
-def union_context(union_types):
+
+UNION_H_INCLUDES = frozenset([
+    'bindings/core/v8/ExceptionState.h',
+    'bindings/core/v8/V8Binding.h',
+    'platform/heap/Handle.h',
+])
+
+cpp_includes = set()
+header_forward_decls = set()
+
+
+def union_context(union_types, interfaces_info):
     return {
-        'containers': [container_context(union_type)
+        'containers': [container_context(union_type, interfaces_info)
                        for union_type in union_types],
+        'cpp_includes': sorted(cpp_includes),
+        'header_forward_decls': sorted(header_forward_decls),
+        'header_includes': sorted(UNION_H_INCLUDES),
     }
 
 
-def container_context(union_type):
+def container_context(union_type, interfaces_info):
+    members = []
+
+    # These variables refer to member contexts if the given union type has
+    # corresponding types. They are used for V8 -> impl conversion.
+    boolean_type = None
+    dictionary_type = None
+    interface_types = []
+    numeric_type = None
+    string_type = None
+    for member in union_type.member_types:
+        context = member_context(member, interfaces_info)
+        members.append(context)
+        if member.is_interface_type:
+            interface_types.append(context)
+        elif member.is_dictionary:
+            if dictionary_type:
+                raise Exception('%s is ambiguous.' % union_type.name)
+            dictionary_type = context
+        elif member.base_type == 'boolean':
+            if boolean_type:
+                raise Exception('%s is ambiguous.' % union_type.name)
+            boolean_type = context
+        elif member.is_numeric_type:
+            if numeric_type:
+                raise Exception('%s is ambiguous.' % union_type.name)
+            numeric_type = context
+        elif member.is_string_type:
+            if string_type:
+                raise Exception('%s is ambiguous.' % union_type.name)
+            string_type = context
+        else:
+            raise Exception('%s is not supported as an union member.' % member.name)
+
     return {
+        'boolean_type': boolean_type,
         'cpp_class': union_type.name,
+        'dictionary_type': dictionary_type,
+        'interface_types': interface_types,
+        'members': members,
+        'numeric_type': numeric_type,
+        'string_type': string_type,
+    }
+
+
+def member_context(member, interfaces_info):
+    cpp_includes.update(member.includes_for_type)
+    interface_info = interfaces_info.get(member.name, None)
+    if interface_info:
+        cpp_includes.update(interface_info.get('dependencies_include_paths', []))
+        header_forward_decls.add(member.name)
+    return {
+        'cpp_name': v8_utilities.uncapitalize(member.name),
+        'cpp_type': member.cpp_type_args(used_in_cpp_sequence=True),
+        'cpp_local_type': member.cpp_type,
+        'cpp_value_to_v8_value': member.cpp_value_to_v8_value(
+            cpp_value='impl.getAs%s()' % member.name, isolate='isolate',
+            creation_context='creationContext'),
+        'rvalue_cpp_type': member.cpp_type_args(used_as_rvalue_type=True),
+        'specific_type_enum': 'SpecificType' + member.name,
+        'type_name': member.name,
+        'v8_value_to_local_cpp_value': member.v8_value_to_local_cpp_value(
+            {}, 'v8Value', 'cppValue', needs_exception_state_for_string=True),
     }