src/DurableTask.Core/Serializing/PackageUpgradeSerializationBinder.cs

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//  Copyright Microsoft Corporation
//  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//  http://www.apache.org/licenses/LICENSE-2.0
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.
//  ----------------------------------------------------------------------------------

namespace DurableTask.Core.Serializing
{
    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Runtime.InteropServices;
    using Newtonsoft.Json.Serialization;

    /// <summary>
    /// SerializationBinder to be used for deserializing DurableTask types that are pre v-2.0, this allows upgrade compatibility.
    /// This is not sufficient to deserialize objects from 1.0 which had the Tags Property set.
    /// </summary>
    [ComVisible(false)]
    public class PackageUpgradeSerializationBinder : DefaultSerializationBinder
    {
        static readonly Lazy<IDictionary<string, Type>> KnownTypes = new Lazy<IDictionary<string, Type>>(() =>
        {
            //Get all types in the DurableTask.Core Namespace
            return typeof(PackageUpgradeSerializationBinder).Assembly.GetTypes()
                .Where(t => t?.Namespace?.StartsWith("DurableTask.Core") ?? false)
                .ToDictionary(x => x.FullName);
        });

        static readonly string CurrentAssemblyName = typeof(PackageUpgradeSerializationBinder).Assembly.GetName().Name;
        static readonly ISet<string> UpgradeableAssemblyNames = new HashSet<string> { "DurableTask", "DurableTaskFx" };

        /// <inheritdoc />
        public override Type BindToType(string assemblyName, string typeName)
        {
            Type resolvedType = null;

            if (assemblyName != CurrentAssemblyName && !string.IsNullOrWhiteSpace(typeName))
            {
                //Separator Index if TypeNameAssemblyFormat Full
                int separatorIndex = assemblyName.IndexOf(',');

                //If no assembly name is specified or this is a type from the v1.0 or vnext assemblies
                if (string.IsNullOrWhiteSpace(assemblyName) || UpgradeableAssemblyNames.Contains(separatorIndex < 0 ? assemblyName : assemblyName.Substring(0, assemblyName.IndexOf(','))))
                {
                    KnownTypes.Value.TryGetValue(typeName.Replace("DurableTask.", "DurableTask.Core."), out resolvedType);
                }
            }

            if (resolvedType == null)
            {
                resolvedType = base.BindToType(assemblyName, typeName);
            }

            return resolvedType;
        }
    };
}