Change mojo enums to be scoped enums in the generated C++ bindings.

Some mojo enums were previously not proper enums: they were constants
for bitfields. These have been replaced by const int32s in the mojoms:
- mus.mojom.EventFlags
- mus.mojom.MouseEventFlags
- mus.mojom.ResizeBehavior
- mus.mojom.WindowTree.AccessPolicy

Some mojo enum values now conflict with macros (mostly on Windows) and
needed to change:
- mus.mojom.Cursor.NULL became CURSOR_NULL (again)
- mus.mojom.KeyboardCode.DELETE became DELETE_KEY
- mus.mojom.WindowManagerErrorCode.ERROR_ACCESS_DENIED became
  ACCESS_DENIED
- device.usb.TransferDirection.IN became INBOUND
- device.usb.TransferDirection.OUT became OUTBOUND
- device.usb.TransferStatus.ERROR became TRANSFER_ERROR
- device.NFCRecordType.OPAQUE became OPAQUE_RECORD
- media.interfaces.Decryptor.Status.ERROR became DECRYPTION_ERROR
- skia.AlphaType.OPAQUE became ALPHA_TYPE_OPAQUE

Review URL: https://codereview.chromium.org/1527183003

Cr-Commit-Position: refs/heads/master@{#370632}

6 files changed, 44 insertions, 10 deletions

diff --git a/mojo/public/tools/bindings/generators/cpp_templates/enum_macros.tmpl b/mojo/public/tools/bindings/generators/cpp_templates/enum_macros.tmpl
index 0e44acd..d11b198 100644
--- a/mojo/public/tools/bindings/generators/cpp_templates/enum_macros.tmpl
+++ b/mojo/public/tools/bindings/generators/cpp_templates/enum_macros.tmpl
@@ -4,12 +4,12 @@
   which case associated functions need to be static.
 ---#}
 {%- macro enum_decl(enum, is_static=false) %}
-enum {{enum.name}} : int32_t {
+enum class {{enum.name}} : int32_t {
 {%- for field in enum.fields %}
 {%-    if field.value %}
-  {{enum.name|to_all_caps}}_{{field.name}} = {{field.value|expression_to_text}},
+  {{field.name}} = {{field.value|expression_to_text}},
 {%-    else %}
-  {{enum.name|to_all_caps}}_{{field.name}},
+  {{field.name}},
 {%-    endif %}
 {%- endfor %}
 };
@@ -27,6 +27,27 @@ enum {{enum.name}} : int32_t {
 bool {{enum.name}}_IsValidValue({{enum.name}} value);
 {%- endmacro %}
 
+{%- macro enum_stream_operator(enum) %}
+inline std::ostream& operator<<(std::ostream& os, {{enum|get_name_for_kind}} value) {
+  switch(value) {
+{%- for _, values in enum.fields|groupby('numeric_value') %}
+    case {{enum|get_name_for_kind}}::{{values[0].name}}:
+      return os << "{{enum|get_name_for_kind}}::
+{%-   if values|length > 1 -%}
+      {{'{'}}
+{%-   endif -%}
+      {{values|map(attribute='name')|join(', ')}}
+{%-   if values|length > 1 -%}
+      {{'}'}}
+{%-   endif -%}
+      ";
+{%- endfor %}
+    default:
+      return os << "Unknown {{enum|get_name_for_kind}} value: " << static_cast<int32_t>(value);
+  }
+}
+{%- endmacro %}
+
 {%- macro is_valid_enum_def(enum, class_name = '') %}
 {% if class_name != '' -%}
 // static
diff --git a/mojo/public/tools/bindings/generators/cpp_templates/module.h.tmpl b/mojo/public/tools/bindings/generators/cpp_templates/module.h.tmpl
index f29d3d8..5ef35a2 100644
--- a/mojo/public/tools/bindings/generators/cpp_templates/module.h.tmpl
+++ b/mojo/public/tools/bindings/generators/cpp_templates/module.h.tmpl
@@ -16,6 +16,7 @@
 #define {{header_guard}}
 
 #include <stdint.h>
+#include <ostream>
 
 #include "mojo/public/cpp/bindings/array.h"
 #include "mojo/public/cpp/bindings/associated_interface_ptr.h"
@@ -49,8 +50,10 @@ namespace {{variant}} {
 
 {#--- Enums #}
 {% from "enum_macros.tmpl" import enum_decl -%}
+{% from "enum_macros.tmpl" import enum_stream_operator -%}
 {%  for enum in enums %}
   {{enum_decl(enum)}}
+  {{enum_stream_operator(enum)}}
 {%- endfor %}
 
 {#--- Constants #}
@@ -158,6 +161,18 @@ typedef mojo::StructPtr<{{union.name}}> {{union.name}}Ptr;
 {%-   endfor %}
 {%- endif %}
 
+{%  for struct in structs %}
+{%    for enum in struct.enums %}
+{{enum_stream_operator(enum)}}
+{%-   endfor %}
+{%- endfor %}
+
+{%  for interface in interfaces %}
+{%    for enum in interface.enums %}
+{{enum_stream_operator(enum)}}
+{%-   endfor %}
+{%- endfor %}
+
 {%- if variant %}
 }  // namespace {{variant}}
 {%- endif %}
diff --git a/mojo/public/tools/bindings/generators/cpp_templates/struct_macros.tmpl b/mojo/public/tools/bindings/generators/cpp_templates/struct_macros.tmpl
index 47068c5..ebc6048 100644
--- a/mojo/public/tools/bindings/generators/cpp_templates/struct_macros.tmpl
+++ b/mojo/public/tools/bindings/generators/cpp_templates/struct_macros.tmpl
@@ -110,6 +110,8 @@
 {%-     else %}
   {{output}}->{{name}} = mojo::internal::AssociatedInterfaceRequestHelper::PassHandle(&{{input_field}}).release();
 {%-     endif %}
+{%-   elif kind|is_enum_kind %}
+  {{output}}->{{name}} = static_cast<int32_t>({{input_field}});
 {%-   else %}
   {{output}}->{{name}} = {{input_field}};
 {%-   endif %}
diff --git a/mojo/public/tools/bindings/generators/cpp_templates/union_serialization_definition.tmpl b/mojo/public/tools/bindings/generators/cpp_templates/union_serialization_definition.tmpl
index 5321d29..f067e64 100644
--- a/mojo/public/tools/bindings/generators/cpp_templates/union_serialization_definition.tmpl
+++ b/mojo/public/tools/bindings/generators/cpp_templates/union_serialization_definition.tmpl
@@ -78,6 +78,8 @@ void SerializeUnion_({{union.name}}Ptr input, mojo::internal::Buffer* buf,
             std::move(*input_acc.data()->{{field.name}}), {{field.name}});
 {%-   elif field.kind|is_associated_kind %}
         // TODO(yzshen): add seralization logic for associated kinds.
+{%    elif field.kind|is_enum_kind %}
+        result->data.f_{{field.name}} = static_cast<int32_t>(input_acc.data()->{{field.name}});
 {%    else %}
         result->data.f_{{field.name}} = input_acc.data()->{{field.name}};
 {%-   endif %}
diff --git a/mojo/public/tools/bindings/generators/mojom_cpp_generator.py b/mojo/public/tools/bindings/generators/mojom_cpp_generator.py
index 45d7476..eb2f03b 100644
--- a/mojo/public/tools/bindings/generators/mojom_cpp_generator.py
+++ b/mojo/public/tools/bindings/generators/mojom_cpp_generator.py
@@ -334,8 +334,7 @@ def TranslateConstants(token, kind):
     if token.parent_kind:
       name.append(token.parent_kind.name)
     if isinstance(token, mojom.EnumValue):
-      name.append(
-          "%s_%s" % (generator.CamelCaseToAllCaps(token.enum.name), token.name))
+      name.extend([token.enum.name, token.name])
     else:
       name.append(token.name)
     return "::".join(name)
@@ -463,7 +462,6 @@ class Generator(generator.Generator):
     "passes_associated_kinds": mojom.PassesAssociatedKinds,
     "struct_size": lambda ps: ps.GetTotalSize() + _HEADER_SIZE,
     "stylize_method": generator.StudlyCapsToCamel,
-    "to_all_caps": generator.CamelCaseToAllCaps,
     "under_to_camel": generator.UnderToCamel,
   }
 
diff --git a/mojo/public/tools/bindings/pylib/mojom/generate/generator.py b/mojo/public/tools/bindings/pylib/mojom/generate/generator.py
index 9c225b4..0ecc615 100644
--- a/mojo/public/tools/bindings/pylib/mojom/generate/generator.py
+++ b/mojo/public/tools/bindings/pylib/mojom/generate/generator.py
@@ -20,10 +20,6 @@ def ExpectedArraySize(kind):
 def StudlyCapsToCamel(studly):
   return studly[0].lower() + studly[1:]
 
-def CamelCaseToAllCaps(camel_case):
-  return '_'.join(
-      word for word in re.split(r'([A-Z][^A-Z]+)', camel_case) if word).upper()
-
 def UnderToCamel(under):
   """Converts underscore_separated strings to CamelCase strings."""
   return ''.join(word.capitalize() for word in under.split('_'))