Generate Mojom Types in Dart (Take 2)

mojo/public/tools/bindings/generators/mojom_dart_generator.py

Index: mojo/public/tools/bindings/generators/mojom_dart_generator.py
diff --git a/mojo/public/tools/bindings/generators/mojom_dart_generator.py b/mojo/public/tools/bindings/generators/mojom_dart_generator.py
index 2adb77b363a42853aa88b45af4de1afd5e5315d8..61c28c6cf9b7a3de412d9fe30f751fc3db9165bb 100644
--- a/mojo/public/tools/bindings/generators/mojom_dart_generator.py
+++ b/mojo/public/tools/bindings/generators/mojom_dart_generator.py
@@ -123,6 +123,32 @@ _kind_to_dart_decl_type = {
   mojom.NULLABLE_STRING:       "String"
 }
 
+_kind_to_mojom_type = {
+  mojom.BOOL:                  "bool",
+  mojom.INT8:                  "int8",
+  mojom.UINT8:                 "uint8",
+  mojom.INT16:                 "int16",
+  mojom.UINT16:                "uint16",
+  mojom.INT32:                 "int32",
+  mojom.UINT32:                "uint32",
+  mojom.FLOAT:                 "float",
+  mojom.HANDLE:                "unspecified",
+  mojom.DCPIPE:                "dataPipeConsumer",
+  mojom.DPPIPE:                "dataPipeProducer",
+  mojom.MSGPIPE:               "messagePipe",
+  mojom.SHAREDBUFFER:          "sharedBuffer",
+  mojom.NULLABLE_HANDLE:       "unspecified",
+  mojom.NULLABLE_DCPIPE:       "dataPipeConsumer",
+  mojom.NULLABLE_DPPIPE:       "dataPipeProducer",
+  mojom.NULLABLE_MSGPIPE:      "messagePipe",
+  mojom.NULLABLE_SHAREDBUFFER: "sharedBuffer",
+  mojom.INT64:                 "int64",
+  mojom.UINT64:                "uint64",
+  mojom.DOUBLE:                "double",
+  mojom.STRING:                "string",
+  mojom.NULLABLE_STRING:       "string"
+}
+
 _spec_to_decode_method = {
   mojom.BOOL.spec:                  'decodeBool',
   mojom.DCPIPE.spec:                'decodeConsumerHandle',
@@ -175,6 +201,16 @@ _spec_to_encode_method = {
   mojom.UINT8.spec:                 'encodeUint8',
 }
 
+# The mojom_types.mojom and service_describer.mojom files are special because
+# they are used to generate mojom Type's and ServiceDescription implementations.
+# They need to be imported, unless the file itself is being generated.
+_service_describer_pkg_short = "service_describer"
+_service_describer_pkg = "package:mojo/mojo/bindings/types/%s.mojom.dart" % \
+  _service_describer_pkg_short
+_mojom_types_pkg_short = "mojom_types"
+_mojom_types_pkg = "package:mojo/mojo/bindings/types/%s.mojom.dart" % \
+  _mojom_types_pkg_short
+
 def GetDartType(kind):
   if kind.imported_from:
     return kind.imported_from["unique_name"] + "." + GetNameForElement(kind)
@@ -225,6 +261,27 @@ def DartDeclType(kind):
   if mojom.IsEnumKind(kind):
     return GetDartType(kind)
 
+def GetMojomTypeValue(kind, typepkg=''):

[zra, 2016/01/15 21:01:33]

I think it would be more consistent to move this logic to a template macro.

[alexfandrianto, 2016/01/20 00:08:28]

Pretty much all the languages use a map for the simple/handle/string kinds, so
the inconsistency must be the string concatenations.

It really takes a lot longer code-wise if I remove the map and need to add more
filters, so I've moved as much of it over as I can without making it overly
painful.

+  if not kind in _kind_to_mojom_type:
+    return ''
+
+  nullable = 'true' if mojom.IsNullableKind(kind) else 'false'
+  w = _kind_to_mojom_type[kind]
+  if kind == mojom.BOOL or kind == mojom.FLOAT or kind == mojom.DOUBLE or \
+    mojom.IsIntegralKind(kind):
+
+    return 'new %sType()..simpleType = %sSimpleType.%s' % (typepkg, typepkg, w)
+  elif mojom.IsAnyHandleKind(kind):
+    return ('new %sType()\n..handleType = (new %sHandleType()' +
+      '\n..kind = %sHandleTypeKind.%s' +
+      '\n..nullable = %s)') % \
+      (typepkg, typepkg, typepkg, w, nullable)
+  elif mojom.IsStringKind(kind):
+    return 'new %sType()\n..stringType = (new %sStringType()..nullable = %s)' \
+      % (typepkg, typepkg, nullable)
+  else:
+    raise Exception('Missing case for kind: %s' % kind)
+
 def NameToComponent(name):
   # insert '_' between anything and a Title name (e.g, HTTPEntry2FooBar ->
   # HTTP_Entry2_FooBar). Numbers terminate a string of lower-case characters.
@@ -426,6 +483,9 @@ def IsPointerArrayKind(kind):
 def IsEnumArrayKind(kind):
   return mojom.IsArrayKind(kind) and mojom.IsEnumKind(kind.kind)
 
+def IsImportedKind(kind):
+  return hasattr(kind, 'imported_from') and kind.imported_from
+
 def ParseStringAttribute(attribute):
   assert isinstance(attribute, basestring)
   return attribute
@@ -436,12 +496,43 @@ def GetPackage(module):
   # Default package.
   return 'mojom'
 
+def GetPackageName(module):
+  return module.name.split('.')[0]
+
 def GetImportUri(module):
   package = GetPackage(module);
   elements = module.namespace.split('.')
   elements.append("%s" % module.name)
   return os.path.join(package, *elements)
 
+def GetIdentifier(kind):

[zra, 2016/01/15 21:01:33]

This name is too generic for what (I think) this function does. The name
generation functions that you're adding should be made more distinct from e.g.
GetNameForElement. There should be no confusion about which one should be used
when the next person comes along to add a feature.

Also, unless the names generated here have some significance outside of Dart,
they should probably use GetNameForElement to make names with Dart styling.

[alexfandrianto, 2016/01/20 00:08:28]

This was combined with GetMojomTypeIdentifier below. This is used to uniquely
identify mojom types across languages.

+  """Use the kind's module to determine the package and name."""
+  # Note: InterfaceRequest's should use the Interface inside them.
+  if hasattr(kind, 'module'):
+    package = GetPackageName(kind.module)
+    name = kind.name
+  elif mojom.IsInterfaceRequestKind(kind):
+    package = GetPackageName(kind.kind.module)
+    name = kind.kind.name
+  else:
+    # These kinds (e.g., simple kinds, maps, and arrays) lack identifiers.
+    raise Exception('Unexpected kind: %s' % kind)
+
+  return '%s_%s' % (package, name)
+
+# Returns a string of the form package.path.TypeName - the full identifier
+# for an element.
+def GetFullIdentifier(element, exported=True):
+  return '%s.%s' % (element.module.namespace, GetNameForElement(element))
+
+def RaiseHelper(msg):
+    raise Exception(msg)
+
+def GetMojomTypeIdentifier(kind):
+  """Get the mojom type's identifier suffix."""
+  # Since this should be unique, it is based on the type's identifier.
+  return "_%s__" % GetIdentifier(kind)

[zra, 2016/01/15 21:01:33]

Why are there trailing underscores?

[alexfandrianto, 2016/01/20 00:08:28]

This has to match between languages, and the Go one already has trailing
underscores.

+
 class Generator(generator.Generator):
 
   dart_filters = {
@@ -450,6 +541,12 @@ class Generator(generator.Generator):
     'decode_method': DecodeMethod,
     'default_value': DartDefaultValue,
     'encode_method': EncodeMethod,
+    'fullidentifier': GetFullIdentifier,
+    'identifier': GetIdentifier,
+    'mojom_type_value': GetMojomTypeValue,
+    'mojom_type_identifier': GetMojomTypeIdentifier,
+    'is_imported_kind': IsImportedKind,
+    'is_array_kind': mojom.IsArrayKind,
     'is_map_kind': mojom.IsMapKind,
     'is_nullable_kind': mojom.IsNullableKind,
     'is_pointer_array_kind': IsPointerArrayKind,
@@ -457,16 +554,25 @@ class Generator(generator.Generator):
     'is_struct_kind': mojom.IsStructKind,
     'is_union_kind': mojom.IsUnionKind,
     'is_enum_kind': mojom.IsEnumKind,
+    'is_interface_kind': mojom.IsInterfaceKind,
+    'is_interface_request_kind': mojom.IsInterfaceRequestKind,
     'dart_true_false': GetDartTrueFalse,
     'dart_type': DartDeclType,
     'name': GetNameForElement,
     'interface_response_name': GetInterfaceResponseName,
     'dot_to_underscore': DotToUnderscore,
     'is_cloneable_kind': mojom.IsCloneableKind,
+    'upper_camel': UpperCamelCase,
+    'raise': RaiseHelper,
   }
 
+  # If set to True, then mojom type information will be generated.
+  should_gen_mojom_types = False
+
   def GetParameters(self, args):
-    return {
+    package = GetPackageName(self.module)
+
+    parameters = {
       "namespace": self.module.namespace,
       "imports": self.GetImports(args),
       "kinds": self.module.kinds,
@@ -477,6 +583,33 @@ class Generator(generator.Generator):
       "interfaces": self.GetInterfaces(),
       "imported_interfaces": self.GetImportedInterfaces(),
       "imported_from": self.ImportedFrom(),
+      "typepkg": '%s.' % _mojom_types_pkg_short,
+      "descpkg": '%s.' % _service_describer_pkg_short,
+      "mojom_types_import": 'import \'%s\' as %s;' % \
+        (_mojom_types_pkg, _mojom_types_pkg_short),
+      "service_describer_import": 'import \'%s\' as %s;' % \
+        (_service_describer_pkg, _service_describer_pkg_short),
+    }
+
+    # If this is the mojom types package, clear the import-related params.
+    if package == _mojom_types_pkg_short:
+      parameters["typepkg"] = ""
+      parameters["mojom_types_import"] = ""
+
+    # If this is the service describer package, clear the import-related params.
+    if package == _service_describer_pkg_short:
+      parameters["descpkg"] = ""
+      parameters["service_describer_import"] = ""
+
+    # If no interfaces were defined, the service describer import isn't needed.
+    if len(self.module.interfaces) == 0:
+      parameters["service_describer_import"] = ""
+
+    return parameters
+
+  def GetGlobals(self):
+    return {
+      'should_gen_mojom_types': self.should_gen_mojom_types,
     }
 
   @UseJinja("dart_templates/module.lib.tmpl", filters=dart_filters)
@@ -485,6 +618,8 @@ class Generator(generator.Generator):
 
 
   def GenerateFiles(self, args):
+    self.should_gen_mojom_types = "--generate_type_info" in args
+
     elements = self.module.namespace.split('.')
     elements.append("%s.dart" % self.module.name)