Allow Mojo structs as map keys

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

Index: mojo/public/tools/bindings/generators/mojom_cpp_generator.py
diff --git a/mojo/public/tools/bindings/generators/mojom_cpp_generator.py b/mojo/public/tools/bindings/generators/mojom_cpp_generator.py
index de906690344d6b1db2664376002d81b77bae5c6a..07eb45bfc3ec2681a844efcd9b5295fe3abc7456 100644
--- a/mojo/public/tools/bindings/generators/mojom_cpp_generator.py
+++ b/mojo/public/tools/bindings/generators/mojom_cpp_generator.py
@@ -152,9 +152,11 @@ def DefaultValue(field):
 def NamespaceToArray(namespace):
   return namespace.split(".") if namespace else []
 
-def GetNameForKind(kind, internal=False, flatten_nested_kind=False):
+def GetNameForKind(kind, internal=False, flatten_nested_kind=False,
+                   add_same_module_namespaces=False):
   return _NameFormatter(kind, _variant).FormatForCpp(
-      internal=internal, flatten_nested_kind=flatten_nested_kind)
+      internal=internal, flatten_nested_kind=flatten_nested_kind,
+      add_same_module_namespaces=add_same_module_namespaces)
 
 def GetQualifiedNameForKind(kind, internal=False, flatten_nested_kind=False):
   return _NameFormatter(kind, _variant).FormatForCpp(
@@ -172,6 +174,45 @@ def IsNativeOnlyKind(kind):
   return (mojom.IsStructKind(kind) or mojom.IsEnumKind(kind)) and \
       kind.native_only
 
+
+def IsHashableKind(kind):
+  """Check if the kind can be hashed.
+
+  Args:
+    kind: {Kind} The kind to check.
+
+  Returns:
+    {bool} True if a value of this kind can be hashed.
+  """
+  checked = set()
+  def Check(kind):
+    if kind.spec in checked:
+      return True
+    checked.add(kind.spec)
+    if mojom.IsNullableKind(kind):
+      return False
+    elif mojom.IsStructKind(kind):
+      if (IsTypemappedKind(kind) and
+          not _current_typemap[GetFullMojomNameForKind(kind)]["hashable"]):
+        return False
+      return all(Check(field.kind) for field in kind.fields)
+    elif mojom.IsUnionKind(kind):
+      return all(Check(field.kind) for field in kind.fields)
+    elif mojom.IsAnyHandleKind(kind):
+      return False
+    elif mojom.IsAnyInterfaceKind(kind):
+      return False
+    # TODO(tibell): Arrays and maps could be made hashable. We just don't have a
+    # use case yet.
+    elif mojom.IsArrayKind(kind):
+      return False
+    elif mojom.IsMapKind(kind):
+      return False
+    else:
+      return True
+  return Check(kind)
+
+
 def GetNativeTypeName(typemapped_kind):
   return _current_typemap[GetFullMojomNameForKind(typemapped_kind)]["typename"]
 
@@ -180,7 +221,7 @@ def GetCppPodType(kind):
     return "char*"
   return _kind_to_cpp_type[kind]
 
-def GetCppWrapperType(kind):
+def GetCppWrapperType(kind, add_same_module_namespaces=False):
   def _AddOptional(type_name):
     pattern = "WTF::Optional<%s>" if _for_blink else "base::Optional<%s>"
     return pattern % type_name
@@ -193,9 +234,11 @@ def GetCppWrapperType(kind):
       type_name = _AddOptional(type_name)
     return type_name
   if mojom.IsEnumKind(kind):
-    return GetNameForKind(kind)
+    return GetNameForKind(
+        kind, add_same_module_namespaces=add_same_module_namespaces)
   if mojom.IsStructKind(kind) or mojom.IsUnionKind(kind):
-    return "%sPtr" % GetNameForKind(kind)
+    return "%sPtr" % GetNameForKind(
+        kind, add_same_module_namespaces=add_same_module_namespaces)
   if mojom.IsArrayKind(kind):
     pattern = None
     if _use_new_wrapper_types:
@@ -204,7 +247,8 @@ def GetCppWrapperType(kind):
         pattern = _AddOptional(pattern)
     else:
       pattern = "mojo::WTFArray<%s>" if _for_blink else "mojo::Array<%s>"
-    return pattern % GetCppWrapperType(kind.kind)
+    return pattern % GetCppWrapperType(
+        kind.kind, add_same_module_namespaces=add_same_module_namespaces)
   if mojom.IsMapKind(kind):
     pattern = None
     if _use_new_wrapper_types:
@@ -214,16 +258,25 @@ def GetCppWrapperType(kind):
         pattern = _AddOptional(pattern)
     else:
       pattern = "mojo::WTFMap<%s, %s>" if _for_blink else "mojo::Map<%s, %s>"
-    return pattern % (GetCppWrapperType(kind.key_kind),
-                      GetCppWrapperType(kind.value_kind))
+    return pattern % (
+        GetCppWrapperType(
+            kind.key_kind,
+            add_same_module_namespaces=add_same_module_namespaces),
+        GetCppWrapperType(
+            kind.value_kind,
+            add_same_module_namespaces=add_same_module_namespaces))
   if mojom.IsInterfaceKind(kind):
-    return "%sPtr" % GetNameForKind(kind)
+    return "%sPtr" % GetNameForKind(
+        kind, add_same_module_namespaces=add_same_module_namespaces)
   if mojom.IsInterfaceRequestKind(kind):
-    return "%sRequest" % GetNameForKind(kind.kind)
+    return "%sRequest" % GetNameForKind(
+        kind.kind, add_same_module_namespaces=add_same_module_namespaces)
   if mojom.IsAssociatedInterfaceKind(kind):
-    return "%sAssociatedPtrInfo" % GetNameForKind(kind.kind)
+    return "%sAssociatedPtrInfo" % GetNameForKind(
+        kind.kind, add_same_module_namespaces=add_same_module_namespaces)
   if mojom.IsAssociatedInterfaceRequestKind(kind):
-    return "%sAssociatedRequest" % GetNameForKind(kind.kind)
+    return "%sAssociatedRequest" % GetNameForKind(
+        kind.kind, add_same_module_namespaces=add_same_module_namespaces)
   if mojom.IsStringKind(kind):
     if _for_blink:
       return "WTF::String"
@@ -313,6 +366,22 @@ def GetUnionGetterReturnType(kind):
     return "%s&" % GetCppWrapperType(kind)
   return GetCppWrapperType(kind)
 
+def GetUnionTraitGetterReturnType(kind):
+  """Get field type used in UnionTraits template specialization.
+
+  The type may be qualified as UnionTraits specializations live outside the
+  namespace where e.g. structs are defined.
+
+  Args:
+    kind: {Kind} The type of the field.
+
+  Returns:
+    {str} The C++ type to use for the field.
+  """
+  if mojom.IsReferenceKind(kind):
+    return "%s&" % GetCppWrapperType(kind, add_same_module_namespaces=True)
+  return GetCppWrapperType(kind, add_same_module_namespaces=True)
+
 def GetCppDataViewType(kind, qualified=False):
   def _GetName(input_kind):
     return _NameFormatter(input_kind, None).FormatForCpp(
@@ -465,6 +534,7 @@ class Generator(generator.Generator):
 
   cpp_filters = {
     "constant_value": ConstantValue,
+    "contains_handles_or_interfaces": mojom.ContainsHandlesOrInterfaces,
     "contains_move_only_members": ContainsMoveOnlyMembers,
     "cpp_wrapper_param_type": GetCppWrapperParamType,
     "cpp_data_view_type": GetCppDataViewType,
@@ -472,6 +542,7 @@ class Generator(generator.Generator):
     "cpp_union_field_type": GetCppUnionFieldType,
     "cpp_pod_type": GetCppPodType,
     "cpp_union_getter_return_type": GetUnionGetterReturnType,
+    "cpp_union_trait_getter_return_type": GetUnionTraitGetterReturnType,
     "cpp_wrapper_type": GetCppWrapperType,
     "default_value": DefaultValue,
     "expression_to_text": ExpressionToText,
@@ -493,9 +564,11 @@ class Generator(generator.Generator):
     "is_any_interface_kind": mojom.IsAnyInterfaceKind,
     "is_any_handle_or_interface_kind": mojom.IsAnyHandleOrInterfaceKind,
     "is_associated_kind": mojom.IsAssociatedKind,
+    "is_hashable": IsHashableKind,
     "is_map_kind": mojom.IsMapKind,
     "is_nullable_kind": mojom.IsNullableKind,
     "is_object_kind": mojom.IsObjectKind,
+    "is_reference_kind": mojom.IsReferenceKind,
     "is_string_kind": mojom.IsStringKind,
     "is_struct_kind": mojom.IsStructKind,
     "is_typemapped_kind": IsTypemappedKind,