buffet: Adding GCD command definition schema - phase 1.
Initial implementation of GCD command definition schema
and parsing command definition provided as JSON.
This change introduces the class hierarchy to describe
parameter type description (ParamType-derived classes),
parameter values (ParamValue-derived classes), constraints,
and general object schema which is a collection of
parameter definition for an object which corresponds
almost directly into a GCD command definition.
Object definition parsing from JSON is implemented
as well as validation of parameter values with rich
error reporting.
This is a basis for future command definition implementation
and device draft definition for GCD devices.
BUG=chromium:374860
TEST=Unit tests pass
Change-Id: I82d185b155956ff31a2d2e33f75bec9605ef32ee
Reviewed-on: https://chromium-review.googlesource.com/201159
Reviewed-by: Christopher Wiley <wiley@chromium.org>
Commit-Queue: Alex Vakulenko <avakulenko@chromium.org>
Tested-by: Alex Vakulenko <avakulenko@chromium.org>
diff --git a/buffet/commands/prop_values.h b/buffet/commands/prop_values.h
new file mode 100644
index 0000000..e03d39b
--- /dev/null
+++ b/buffet/commands/prop_values.h
@@ -0,0 +1,144 @@
+// 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.
+
+#ifndef BUFFET_COMMANDS_PROP_VALUES_H_
+#define BUFFET_COMMANDS_PROP_VALUES_H_
+
+#include <map>
+#include <memory>
+#include <string>
+
+#include "buffet/commands/prop_constraints.h"
+#include "buffet/error.h"
+
+namespace base {
+class Value;
+class DictionaryValue;
+} // namespace base
+
+namespace buffet {
+
+// Enumeration to indicate supported command parameter types.
+enum class ValueType {
+ Int,
+ Double,
+ String,
+ Boolean
+};
+
+// 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.
+template<> ValueType GetValueType<int>();
+template<> ValueType GetValueType<double>();
+template<> ValueType GetValueType<std::string>();
+template<> ValueType GetValueType<bool>();
+
+class ObjectSchema;
+
+class PropValue;
+class IntPropType;
+class DoublePropType;
+class StringPropType;
+class BooleanPropType;
+
+class IntValue;
+class DoubleValue;
+class StringValue;
+class BooleanValue;
+
+// The base class for parameter values.
+// Concrete value classes of various types will be derived from this base.
+class PropValue {
+ public:
+ PropValue() = default;
+ 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; }
+
+ // Makes a full copy of this value class.
+ virtual std::shared_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(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, ErrorPtr* error) = 0;
+};
+
+// A helper template base class for implementing simple (non-Object) value
+// classes.
+template<typename Derived, typename T>
+class TypedValueBase : public PropValue {
+ public:
+ // Overrides from PropValue base class.
+ virtual ValueType GetType() const override { return GetValueType<T>(); }
+ virtual std::shared_ptr<PropValue> Clone() const override {
+ return std::make_shared<Derived>(*static_cast<const Derived*>(this));
+ }
+
+ virtual std::unique_ptr<base::Value> ToJson(ErrorPtr* error) const override {
+ (void)error; // unused.
+ return TypedValueToJson(value_);
+ }
+
+ virtual bool FromJson(const base::Value* value, ErrorPtr* error) override {
+ return TypedValueFromJson(value, &value_, error);
+ }
+
+ // Helper method to get and set the C++ representation of the value.
+ const T& GetValue() const { return value_; }
+ void SetValue(T value) { value_ = std::move(value); }
+
+ protected:
+ T value_{}; // The value of the parameter in C++ data representation.
+};
+
+// Value of type Integer.
+class IntValue final : public TypedValueBase<IntValue, int> {
+ public:
+ virtual IntValue* GetInt() override { return this; }
+ virtual IntValue const* GetInt() const override { return this; }
+};
+
+// Value of type Number.
+class DoubleValue final : public TypedValueBase<DoubleValue, double> {
+ public:
+ virtual DoubleValue* GetDouble() override { return this; }
+ virtual DoubleValue const* GetDouble() const override { return this; }
+};
+
+// Value of type String.
+class StringValue final : public TypedValueBase<StringValue, std::string> {
+ public:
+ virtual StringValue* GetString() override { return this; }
+ virtual StringValue const* GetString() const override { return this; }
+};
+
+// Value of type Boolean.
+class BooleanValue final : public TypedValueBase<BooleanValue, bool> {
+ public:
+ virtual BooleanValue* GetBoolean() override { return this; }
+ virtual BooleanValue const* GetBoolean() const override { return this; }
+};
+
+} // namespace buffet
+
+#endif // BUFFET_COMMANDS_PROP_VALUES_H_
