text: //
  // Copyright (c) 2008-2019 the Urho3D project.
  //
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to deal
  // in the Software without restriction, including without limitation the rights
  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  // copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions:
  //
  // The above copyright notice and this permission notice shall be included in
  // all copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  // THE SOFTWARE.
  //
  
  /// \file
  
  #pragma once
  
  #include "../Container/FlagSet.h"
  #include "../Container/Ptr.h"
  #include "../Core/Variant.h"
  
  namespace Urho3D
  {
  
  enum AttributeMode
  {
      /// Attribute shown only in the editor, but not serialized.
      AM_EDIT = 0x0,
      /// Attribute used for file serialization.
      AM_FILE = 0x1,
      /// Attribute used for network replication.
      AM_NET = 0x2,
      /// Attribute used for both file serialization and network replication (default).
      AM_DEFAULT = 0x3,
      /// Attribute should use latest data grouping instead of delta update in network replication.
      AM_LATESTDATA = 0x4,
      /// Attribute should not be shown in the editor.
      AM_NOEDIT = 0x8,
      /// Attribute is a node ID and may need rewriting.
      AM_NODEID = 0x10,
      /// Attribute is a component ID and may need rewriting.
      AM_COMPONENTID = 0x20,
      /// Attribute is a node ID vector where first element is the amount of nodes.
      AM_NODEIDVECTOR = 0x40,
      /// Attribute is readonly. Can't be used with binary serialized objects.
      AM_FILEREADONLY = 0x81,
  };
  URHO3D_FLAGSET(AttributeMode, AttributeModeFlags);
  
  class Serializable;
  
  /// Abstract base class for invoking attribute accessors.
  class URHO3D_API AttributeAccessor : public RefCounted
  {
  public:
      /// Get the attribute.
      virtual void Get(const Serializable* ptr, Variant& dest) const = 0;
      /// Set the attribute.
      virtual void Set(Serializable* ptr, const Variant& src) = 0;
  };
  
  /// Description of an automatically serializable variable.
  struct AttributeInfo
  {
      /// Construct empty.
      AttributeInfo() = default;
  
      /// Construct attribute.
      AttributeInfo(VariantType type, const char* name, const SharedPtr<AttributeAccessor>& accessor, const char** enumNames, const Variant& defaultValue, AttributeModeFlags mode) :
          type_(type),
          name_(name),
          enumNames_(enumNames),
          accessor_(accessor),
          defaultValue_(defaultValue),
          mode_(mode)
      {
      }
  
      /// Get attribute metadata.
      const Variant& GetMetadata(const StringHash& key) const
      {
          auto elem = metadata_.Find(key);
          return elem != metadata_.End() ? elem->second_ : Variant::EMPTY;
      }
  
      /// Get attribute metadata of specified type.
      template <class T> T GetMetadata(const StringHash& key) const
      {
          return GetMetadata(key).Get<T>();
      }
  
      /// Attribute type.
      VariantType type_ = VAR_NONE;
      /// Name.
      String name_;
      /// Enum names.
      const char** enumNames_ = nullptr;
      /// Helper object for accessor mode.
      SharedPtr<AttributeAccessor> accessor_;
      /// Default value for network replication.
      Variant defaultValue_;
      /// Attribute mode: whether to use for serialization, network replication, or both.
      AttributeModeFlags mode_ = AM_DEFAULT;
      /// Attribute metadata.
      VariantMap metadata_;
      /// Attribute data pointer if elsewhere than in the Serializable.
      void* ptr_ = nullptr;
  };
  
  /// Attribute handle returned by Context::RegisterAttribute and used to chain attribute setup calls.
  struct AttributeHandle
  {
      friend class Context;
  private:
      /// Construct default.
      AttributeHandle() = default;
      /// Construct from another handle.
      AttributeHandle(const AttributeHandle& another) = default;
      /// Attribute info.
      AttributeInfo* attributeInfo_ = nullptr;
      /// Network attribute info.
      AttributeInfo* networkAttributeInfo_ = nullptr;
  public:
      /// Set metadata.
      AttributeHandle& SetMetadata(StringHash key, const Variant& value)
      {
          if (attributeInfo_)
              attributeInfo_->metadata_[key] = value;
          if (networkAttributeInfo_)
              networkAttributeInfo_->metadata_[key] = value;
          return *this;
      }
  };
  
  }
  