IDL: Drop redundant null check for string and wrapper type attributes

Source/bindings/scripts/v8_types.py

 # Copyright (C) 2013 Google Inc. All rights reserved.
 #
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 # modification, are permitted provided that the following conditions are
 # met:
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 #     * Redistributions of source code must retain the above copyright
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 #     * Redistributions in binary form must reproduce the above
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@@ skipping 540 matching lines @@
         return 'array'
 
     # Simple types
     base_idl_type = idl_type.base_type
     # Basic types, without additional includes
     if base_idl_type in CPP_INT_TYPES:
         return 'int'
     if base_idl_type in CPP_UNSIGNED_TYPES:
         return 'unsigned'
     if idl_type.is_string_type:
+        if idl_type.is_nullable:
+            return 'StringOrNull'
         if 'TreatReturnedNullStringAs' not in extended_attributes:
             return base_idl_type
         treat_returned_null_string_as = extended_attributes['TreatReturnedNullStringAs']
         if treat_returned_null_string_as == 'Null':
             return 'StringOrNull'
         if treat_returned_null_string_as == 'Undefined':
             return 'StringOrUndefined'
         raise 'Unrecognized TreatReturnNullStringAs value: "%s"' % treat_returned_null_string_as
     if idl_type.is_basic_type or base_idl_type == 'ScriptValue':
         return base_idl_type
@@ skipping 98 matching lines @@
     'ByteString': 'v8String({isolate}, {cpp_value})',
     'ScalarValueString': 'v8String({isolate}, {cpp_value})',
     'boolean': 'v8Boolean({cpp_value}, {isolate})',
     'int': 'v8::Integer::New({isolate}, {cpp_value})',
     'unsigned': 'v8::Integer::NewFromUnsigned({isolate}, {cpp_value})',
     'float': 'v8::Number::New({isolate}, {cpp_value})',
     'unrestricted float': 'v8::Number::New({isolate}, {cpp_value})',
     'double': 'v8::Number::New({isolate}, {cpp_value})',
     'unrestricted double': 'v8::Number::New({isolate}, {cpp_value})',
     'void': 'v8Undefined()',
+    # [TreatNullReturnValueAs]
+    'StringOrNull': '!{cpp_value}.isNull() ? v8String({isolate}, {cpp_value}) : v8::Handle<v8::Value>(v8::Null({isolate}))',

[haraken, 2014/07/01 00:57:33]

Flip the order and avoid a negation.

{cpp_value}.isNull() ? v8::Handle<v8::Value>(v8::Null({isolate})) :
v8String({isolate}, {cpp_value})

Do we have a run-bindings-test for this? I couldn't find a diff caused by this
change.

[Jens Widell, 2014/07/01 06:43:22]

Done.

+    'StringOrUndefined': '!{cpp_value}.isNull() ? v8String({isolate}, {cpp_value}) : v8Undefined()',

[haraken, 2014/07/01 00:57:33]

Ditto.

BTW, who needs StringOrUndefined? The behavior sounds a bit strange in terms of
the spec.

[Jens Widell, 2014/07/01 06:43:22]

A bit strange, yes. Kicks in with [TreatReturnedNullStringAs=Undefined], which
is used in a few places in real IDL files. Somewhat unclear if any of them
actually ever return a null string, so this may be dead code.

These added code snippets don't end up anywhere in generated code with current
IDL files, but the dictionary items are always accessed to calculate (unused)
attribute context values, so not having them raises KeyError.

I've added tests for the cases where they would be used; DOMString? or
[TreatReturnedNullStringAs] combined with [CachedAttribute] or
[LogPreviousValue].

     # Special cases
     'EventHandler': '{cpp_value} ? v8::Handle<v8::Value>(V8AbstractEventListener::cast({cpp_value})->getListenerObject(impl->executionContext())) : v8::Handle<v8::Value>(v8::Null({isolate}))',
     'ScriptValue': '{cpp_value}.v8Value()',
     'SerializedScriptValue': '{cpp_value} ? {cpp_value}->deserialize() : v8::Handle<v8::Value>(v8::Null({isolate}))',
     # General
     'array': 'v8Array({cpp_value}, {creation_context}, {isolate})',
     'DOMWrapper': 'toV8({cpp_value}, {creation_context}, {isolate})',
 }
 
 
@@ skipping 11 matching lines @@
 
 def literal_cpp_value(idl_type, idl_literal):
     """Converts an expression that is a valid C++ literal for this type."""
     # FIXME: add validation that idl_type and idl_literal are compatible
     literal_value = str(idl_literal)
     if idl_type.base_type in CPP_UNSIGNED_TYPES:
         return literal_value + 'u'
     return literal_value
 
 IdlType.literal_cpp_value = literal_cpp_value