media_perception/mojom/values.mojom

// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

module mojo_base.mojom;

// Value represents a value that can be serialized to/from JSON.
//
// One notable caveat is that Value supports arbitrary binary data, which JSON
// does not support natively.
union Value {
  // Null type placeholder. This field is never used.
  uint8 null_value;
  // Primitive types.
  bool bool_value;
  int32 int_value;
  double double_value;
  // Unicode string.
  string string_value;
  // Binary blob with arbitrary bytes. Not supported for JSON.
  array<uint8> binary_value;
  // Basic container support for lists and maps.
  DictionaryValue dictionary_value;
  ListValue list_value;
};

// Interfaces that only want to handle a value of dictionary or list type
// should use base.mojom.DictionaryValue or base.mojom.ListValue in the method
// declaration. Currently, both of these are typemapped to base::Value, though
// once all existing usage is swapped over to the deprecated versions below,
// the typemap will be updated to deserialize as a base::Value::Dict and
// base::Value::List respectively instead.
struct DictionaryValue {
  map<string, Value> storage;
};

struct ListValue {
  array<Value> storage;
};

// Legacy versions of the above dictionary and list value types. Both are
// unconditionally typemapped to base::Value. Though the typemap ensures that
// the deserialized base::Value has a matching subtype, use of these will be
// removed in the future due to lack of type safety.
struct DeprecatedDictionaryValue {
  map<string, Value> storage;
};

struct DeprecatedListValue {
  array<Value> storage;
};