// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
 
using Microsoft.CodeAnalysis.Serialization;
using Roslyn.Utilities;
 
namespace Microsoft.CodeAnalysis.Remote
{
    /// <summary>
    /// Represents a part of solution snapshot along with its checksum.
    /// </summary>
    internal sealed class SolutionAsset
    {
        public static readonly SolutionAsset Null = new(value: null, Checksum.Null, WellKnownSynchronizationKind.Null);
 
        /// <summary>
        /// Indicates what kind of object it.
        /// 
        /// Used in transportation framework and deserialization service to hand shake how to send over data and
        /// deserialize serialized data.
        /// </summary>
        public readonly WellKnownSynchronizationKind Kind;
 
        /// <summary>
        /// Checksum of <see cref="Value"/>.
        /// </summary>
        public readonly Checksum Checksum;
 
        public readonly object? Value;
 
        public SolutionAsset(object? value, Checksum checksum, WellKnownSynchronizationKind kind)
        {
            // SolutionAsset is not allowed to hold strong references to SourceText. SerializableSourceText is used
            // instead to allow data to be released from process address space when it is also held in temporary
            // storage.
            // https://github.com/dotnet/roslyn/issues/43802
            Contract.ThrowIfTrue(kind is WellKnownSynchronizationKind.SourceText);
 
            Checksum = checksum;
            Kind = kind;
            Value = value;
        }
 
        public SolutionAsset(Checksum checksum, object value)
            : this(value, checksum, value.GetWellKnownSynchronizationKind())
        {
        }
    }
}