blob: 228316fe91a6b4754ebbd9c0bc7b1d13595cde3d [file] [log] [blame]
// Copyright 2014 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <map>
#include <memory>
#include <string>
#include <chromeos/any.h>
#include <chromeos/errors/error.h>
#include "buffet/commands/schema_utils.h"
namespace base {
class Value;
class DictionaryValue;
} // namespace base
namespace buffet {
// Enumeration to indicate supported command parameter types.
enum class ValueType {
class PropValue;
class IntValue;
class DoubleValue;
class StringValue;
class BooleanValue;
class ObjectValue;
class ArrayValue;
class PropType;
// Helper methods to get the parameter type enum value for the given
// native C++ data representation.
// The generic GetValueType<T>() is undefined, however particular
// type specializations return the appropriate ValueType.
template<typename T> ValueType GetValueType(); // Undefined.
inline ValueType GetValueType<int>() { return ValueType::Int; }
inline ValueType GetValueType<double>() { return ValueType::Double; }
inline ValueType GetValueType<std::string>() { return ValueType::String; }
inline ValueType GetValueType<bool>() { return ValueType::Boolean; }
inline ValueType GetValueType<native_types::Object>() {
return ValueType::Object;
inline ValueType GetValueType<native_types::Array>() {
return ValueType::Array;
// The base class for property values.
// Concrete value classes of various types will be derived from this base.
// A property value is the actual command parameter value (or a concrete value
// that can be used in constraints and presets). The PropValue is mostly
// just parsed content of base::Value when a command is dispatched, however
// it does have some additional functionality:
// - it has a reference to the type definition (PropType) which is used
// when validating the value, especially for "object" types.
// - it can be compared with another instances of values of the same type.
// This is used to validate the values against "enum"/"one of" constraints.
class PropValue {
explicit PropValue(std::unique_ptr<const PropType> type);
// Special out-of-line constructor to help implement PropValue::Clone().
// That method needs to clone the underlying type but can't do this in this
// header file since PropType is just forward-declared (it needs PropValue
// fully defined in its own inner workings).
explicit PropValue(const PropType* type_ptr);
virtual ~PropValue();
// Gets the type of the value.
virtual ValueType GetType() const = 0;
// Type conversion methods. Used in lieu of RTTI and dynamic_cast<>.
virtual IntValue* GetInt() { return nullptr; }
virtual IntValue const* GetInt() const { return nullptr; }
virtual DoubleValue* GetDouble() { return nullptr; }
virtual DoubleValue const* GetDouble() const { return nullptr; }
virtual StringValue* GetString() { return nullptr; }
virtual StringValue const* GetString() const { return nullptr; }
virtual BooleanValue* GetBoolean() { return nullptr; }
virtual BooleanValue const* GetBoolean() const { return nullptr; }
virtual ObjectValue* GetObject() { return nullptr; }
virtual ObjectValue const* GetObject() const { return nullptr; }
virtual ArrayValue* GetArray() { return nullptr; }
virtual ArrayValue const* GetArray() const { return nullptr; }
// Makes a full copy of this value class.
virtual std::unique_ptr<PropValue> Clone() const = 0;
// Saves the value as a JSON object.
// If it fails, returns nullptr value and fills in the details for the
// failure in the |error| parameter.
virtual std::unique_ptr<base::Value> ToJson(
chromeos::ErrorPtr* error) const = 0;
// Parses a value from JSON.
// If it fails, it returns false and provides additional information
// via the |error| parameter.
virtual bool FromJson(const base::Value* value,
chromeos::ErrorPtr* error) = 0;
// Returns the contained C++ value as Any.
virtual chromeos::Any GetValueAsAny() const = 0;
// Return the type definition of this value.
const PropType* GetPropType() const { return type_.get(); }
// Compares two values and returns true if they are equal.
virtual bool IsEqual(const PropValue* value) const = 0;
std::unique_ptr<const PropType> type_;
// A helper template base class for implementing value classes.
template<typename Derived, typename T>
class TypedValueBase : public PropValue {
// To help refer to this base class from derived classes, define Base to
// be this class.
using Base = TypedValueBase<Derived, T>;
// Expose the non-default constructor of the base class.
using PropValue::PropValue;
// Overrides from PropValue base class.
ValueType GetType() const override { return GetValueType<T>(); }
std::unique_ptr<PropValue> Clone() const override {
std::unique_ptr<Derived> derived{new Derived{type_.get()}};
derived->value_ = value_;
return std::move(derived);
std::unique_ptr<base::Value> ToJson(
chromeos::ErrorPtr* error) const override {
return TypedValueToJson(value_, error);
bool FromJson(const base::Value* value, chromeos::ErrorPtr* error) override {
return TypedValueFromJson(value, GetPropType(), &value_, error);
bool IsEqual(const PropValue* value) const override {
if (GetType() != value->GetType())
return false;
const Base* value_base = static_cast<const Base*>(value);
return CompareValue(GetValue(), value_base->GetValue());
// Helper methods to get and set the C++ representation of the value.
chromeos::Any GetValueAsAny() const override { return value_; }
const T& GetValue() const { return value_; }
void SetValue(T value) { value_ = std::move(value); }
T value_{}; // The value of the parameter in C++ data representation.
// Value of type Integer.
class IntValue final : public TypedValueBase<IntValue, int> {
using Base::Base; // Expose the custom constructor of the base class.
IntValue* GetInt() override { return this; }
IntValue const* GetInt() const override { return this; }
// Value of type Number.
class DoubleValue final : public TypedValueBase<DoubleValue, double> {
using Base::Base; // Expose the custom constructor of the base class.
DoubleValue* GetDouble() override { return this; }
DoubleValue const* GetDouble() const override { return this; }
// Value of type String.
class StringValue final : public TypedValueBase<StringValue, std::string> {
using Base::Base; // Expose the custom constructor of the base class.
StringValue* GetString() override { return this; }
StringValue const* GetString() const override { return this; }
// Value of type Boolean.
class BooleanValue final : public TypedValueBase<BooleanValue, bool> {
using Base::Base; // Expose the custom constructor of the base class.
BooleanValue* GetBoolean() override { return this; }
BooleanValue const* GetBoolean() const override { return this; }
// Value of type Object.
class ObjectValue final
: public TypedValueBase<ObjectValue, native_types::Object> {
using Base::Base; // Expose the custom constructor of the base class.
ObjectValue* GetObject() override { return this; }
ObjectValue const* GetObject() const override { return this; }
// Value of type Array.
class ArrayValue final
: public TypedValueBase<ArrayValue, native_types::Array> {
using Base::Base; // Expose the custom constructor of the base class.
ArrayValue* GetArray() override { return this; }
ArrayValue const* GetArray() const override { return this; }
} // namespace buffet