Revert of Revert of IDL: Support optional argument default value synt…

…ax (https://codereview.chromium.org/339683002/)

Reason for revert:
Revert the revert because the bot went green even without this revert, and other bots had no trouble.

Original issue's description:
> Revert of IDL: Support optional argument default value syntax (https://codereview.chromium.org/312683005/)
> 
> Reason for revert:
> This patch is the most likely candidate for browser test failures: http://build.chromium.org/p/chromium.webkit/builders/Linux%20Tests%20%28dbg%29/builds/2905
> 
> BrowserTestBase signal handler received SIGTERM. Backtrace:
> #0 0x7f2c2a201a1d base::debug::StackTrace::StackTrace()
> #1 0x00000460caf2 content::(anonymous namespace)::DumpStackTraceSignalHandler()
> #2 0x7f2c232cd4a0 \u003Cunknown>
> #3 0x7f2c2337f313 __poll
> #4 0x7f2c240b6036 \u003Cunknown>
> #5 0x7f2c240b6164 g_main_context_iteration
> #6 0x7f2c2a1c9b45 base::MessagePumpGlib::Run()
> #7 0x7f2c2a29eed7 base::MessageLoop::RunHandler()
> #8 0x7f2c2a2f69d8 base::RunLoop::Run()
> #9 0x00000466bd59 content::RunThisRunLoop()
> #10 0x00000466c1b8 content::MessageLoopRunner::Run()
> #11 0x000004610946 content::TitleWatcher::WaitAndGetTitle()
> #12 0x0000011fdf00 MediaBrowserTest::RunTest()
> #13 0x0000011fdc00 MediaBrowserTest::RunMediaTestPage()
> #14 0x0000011ec98b EncryptedMediaTestBase::RunEncryptedMediaTestPage()
> #15 0x0000011ee5fa EncryptedMediaTest::TestConfigChange()
> #16 0x0000011eb73a EncryptedMediaTest_ConfigChangeVideo_Test::RunTestOnMainThread()
> ...
> 
> Please look into it. An alterate possible candidate is  https://codereview.chromium.org/327553002 but I think that's less likely.
> 
> Original issue's description:
> > IDL: Support optional argument default value syntax
> > 
> > Adds support for parsing default values of different types, but
> > only handles null default values when generating code.
> > 
> > Replaces existing
> > 
> >   [Default=Null] optional SomeInterface arg
> >   [Default=NullString] optional DOMString arg
> > 
> > with the now equivalent
> > 
> >   optional SomeInterface arg = null
> >   optional DOMString arg = null
> > 
> > in IDL files, and drops support for those [Default] attributes.
> > 
> > No changes to generated code.
> > 
> > BUG=258153
> > 
> > Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=176200
> 
> [email protected],[email protected],[email protected],[email protected],[email protected]
> NOTREECHECKS=true
> NOTRY=true
> BUG=258153
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=176220

[email protected],[email protected],[email protected],[email protected],[email protected]
NOTREECHECKS=true
NOTRY=true
BUG=258153

Review URL: https://codereview.chromium.org/339723002

git-svn-id: svn://svn.chromium.org/blink/trunk@176231 bbb929c8-8fbe-4397-9dbb-9b2b20218538

Source/bindings/IDLExtendedAttributes.txt

@@ -46,7 +46,7 @@ ConstructorCallWith=ExecutionContext|Document
 Custom=|Getter|Setter|LegacyCallAsFunction|ToV8|VisitDOMWrapper|Wrap|PropertyGetter|PropertyEnumerator|PropertyQuery
 CustomConstructor
 CustomElementCallbacks
-Default=Null|NullString|Undefined
+Default=Undefined
 DependentLifetime
 DeprecateAs=*
 DoNotCheckConstants

Source/bindings/scripts/idl_definitions.py

@@ -393,6 +393,59 @@ def __init__(self, node):
             self.extended_attributes = {}
 
 
+################################################################################
+# Literals
+################################################################################
+
+class IdlLiteral(object):
+    def __init__(self, idl_type, value):
+        self.idl_type = idl_type
+        self.value = value
+        self.is_null = False
+
+    def __str__(self):
+        if self.idl_type == 'DOMString':
+            return 'String("%s")' % self.value
+        if self.idl_type == 'integer':
+            return '%d' % self.value
+        if self.idl_type == 'float':
+            return '%g' % self.value
+        if self.idl_type == 'boolean':
+            return 'true' if self.value else 'false'
+        raise ValueError('Unsupported literal type: %s' % self.idl_type)
+
+
+class IdlLiteralNull(IdlLiteral):
+    def __init__(self):
+        self.idl_type = 'NULL'
+        self.value = None
+        self.is_null = True
+
+    def __str__(self):
+        return 'nullptr'
+
+
+def default_node_to_idl_literal(node):
+    # FIXME: This code is unnecessarily complicated due to the rather
+    # inconsistent way the upstream IDL parser outputs default values.
+    # http://crbug.com/374178
+    idl_type = node.GetProperty('TYPE')
+    if idl_type == 'DOMString':
+        value = node.GetProperty('NAME')
+        if '"' in value or '\\' in value:
+            raise ValueError('Unsupported string value: %r' % value)
+        return IdlLiteral(idl_type, value)
+    if idl_type == 'integer':
+        return IdlLiteral(idl_type, int(node.GetProperty('NAME')))
+    if idl_type == 'float':
+        return IdlLiteral(idl_type, float(node.GetProperty('VALUE')))
+    if idl_type == 'boolean':
+        return IdlLiteral(idl_type, node.GetProperty('VALUE'))
+    if idl_type == 'NULL':
+        return IdlLiteralNull()
+    raise ValueError('Unrecognized default value type: %s' % idl_type)
+
+
 ################################################################################
 # Operations
 ################################################################################
@@ -475,6 +528,7 @@ def __init__(self, node):
         self.is_optional = node.GetProperty('OPTIONAL')  # syntax: (optional T)
         self.is_variadic = False  # syntax: (T...)
         self.name = node.GetName()
+        self.default_value = None
 
         children = node.GetChildren()
         for child in children:
@@ -488,6 +542,8 @@ def __init__(self, node):
                 if child_name != '...':
                     raise ValueError('Unrecognized Argument node; expected "...", got "%s"' % child_name)
                 self.is_variadic = child.GetProperty('ELLIPSIS') or False
+            elif child_class == 'Default':
+                self.default_value = default_node_to_idl_literal(child)
             else:
                 raise ValueError('Unrecognized node class: %s' % child_class)
 

Source/bindings/scripts/v8_methods.py

@@ -181,8 +181,11 @@ def generate_argument(interface, method, argument, index):
                                            used_as_argument=True,
                                            used_as_variadic_argument=argument.is_variadic),
         'cpp_value': this_cpp_value,
+        # FIXME: check that the default value's type is compatible with the argument's
+        'default_value': str(argument.default_value) if argument.default_value else None,
         'enum_validation_expression': idl_type.enum_validation_expression,
-        'has_default': 'Default' in extended_attributes,
+        # FIXME: remove once [Default] removed and just use argument.default_value
+        'has_default': 'Default' in extended_attributes or argument.default_value,
         'has_event_listener_argument': any(
             argument_so_far for argument_so_far in method.arguments[:index]
             if argument_so_far.idl_type.name == 'EventListener'),
@@ -298,9 +301,10 @@ def v8_value_to_local_cpp_value(argument, index):
     name = argument.name
     if argument.is_variadic:
         return v8_value_to_local_cpp_variadic_value(argument, index)
-    # [Default=NullString]
+    # FIXME: This special way of handling string arguments with null defaults
+    # can go away once we fully support default values.
     if (argument.is_optional and idl_type.name in ('String', 'ByteString') and
-        extended_attributes.get('Default') == 'NullString'):
+        argument.default_value and argument.default_value.is_null):
         v8_value = 'argumentOrNull(info, %s)' % index
     else:
         v8_value = 'info[%s]' % index

Source/bindings/tests/idls/TestInterfaceConstructor2.idl

@@ -44,7 +44,7 @@
         TestInterfaceEmpty testInterfaceEmptyArg,
         long longArg,
         [Default=Undefined] optional DOMString defaultUndefinedOptionalStringArg,
-        [Default=NullString] optional DOMString defaultNullStringOptionalStringArg,
+        optional DOMString defaultNullStringOptionalStringArg = null,
         [Default=Undefined] optional Dictionary defaultUndefinedOptionalDictionaryArg,
         optional DOMString optionalStringArg),
 ] interface TestInterfaceConstructor2 {

Source/bindings/tests/idls/TestInterfaceNamedConstructor.idl

@@ -33,7 +33,7 @@
         [Default=Undefined] optional boolean defaultUndefinedOptionalBooleanArg,
         [Default=Undefined] optional long defaultUndefinedOptionalLongArg,
         [Default=Undefined] optional DOMString defaultUndefinedOptionalStringArg,
-        [Default=NullString] optional DOMString defaultNullStringOptionalstringArg,
+        optional DOMString defaultNullStringOptionalstringArg = null,
         optional DOMString optionalStringArg),
     RaisesException=Constructor,
 ] interface TestInterfaceNamedConstructor {

Source/bindings/tests/idls/TestObject.idl

@@ -379,6 +379,16 @@ interface TestObject {
     // Optional arguments: exceptional case
     void voidMethodOptionalDictionaryArg(optional Dictionary optionalDictionaryArg);
 
+    // Optional arguments with defaults
+    void voidMethodDefaultStringArg(optional DOMString defaultStringArg = "foo");
+    void voidMethodDefaultNullStringArg(optional DOMString defaultStringArg = null);
+    void voidMethodDefaultLongArg(optional long defaultLongArg = 10);
+    void voidMethodDefaultDoubleArg(optional double defaultDoubleArg = 0.5);
+    void voidMethodDefaultTrueBooleanArg(optional boolean defaultBooleanArg = true);
+    void voidMethodDefaultFalseBooleanArg(optional boolean defaultBooleanArg = false);
+    void voidMethodDefaultNullableStringArg(optional DOMString? defaultStringArg = null);
+    void voidMethodDefaultNullableTestInterfaceArg(optional TestInterface? defaultTestInterfaceArg = null);
+
     // Variadic operations
     void voidMethodVariadicStringArg(DOMString... variadicStringArgs);
     void voidMethodStringArgVariadicStringArg(DOMString stringArg, DOMString... variadicStringArgs);
@@ -401,7 +411,7 @@ interface TestObject {
     void overloadedMethodF(optional DOMString stringArg);
     void overloadedMethodF(double doubleArg);
     void overloadedMethodG(long longArg);
-    void overloadedMethodG([Default=Null] TestInterfaceEmpty? testInterfaceEmptyOrNullArg);
+    void overloadedMethodG(optional TestInterfaceEmpty? testInterfaceEmptyOrNullArg = null);
     void overloadedMethodH(TestInterface testInterfaceArg);
     void overloadedMethodH(TestInterfaceEmpty testInterfaceEmptyArg);
     void overloadedMethodI(DOMString stringArg);
@@ -422,7 +432,6 @@ interface TestObject {
     void voidMethodDefaultUndefinedTestInterfaceEmptyArg([Default=Undefined] optional TestInterfaceEmpty defaultUndefinedTestInterfaceEmptyArg);
     void voidMethodDefaultUndefinedLongArg([Default=Undefined] optional long defaultUndefinedLongArg);
     void voidMethodDefaultUndefinedStringArg([Default=Undefined] optional DOMString defaultUndefinedStringArg);
-    void voidMethodDefaultNullStringStringArg([Default=NullString] optional DOMString defaultNullStringStringArg);
     // [EnforceRange]
     void voidMethodEnforceRangeLongArg([EnforceRange] long enforceRangeLongArg);
     // [TreatNullAs], [TreatUndefinedAs]