ICompletableWithResult.cs

#nullable enable

using Newtonsoft.Json;

namespace OpenServiceBroker;

/// <summary>
/// An async/deferred operation that can also be completed and provide a result synchronously.
/// </summary>
public interface ICompletableWithResult<T> : ICompletable
    where T : class
{
    /// <summary>
    /// If <see cref="ICompletable.Completed"/> is <c>true</c> this holds the result of the operation.
    /// </summary>
    /// <remarks>This is not part of the Open Service Broker JSON representation. Instead it is communicated out of band via HTTP status codes.</remarks>
    [JsonIgnore]
    T? Result { get; set; }
}

public static class CompletableWithResult
{
    /// <summary>
    /// Marks an operation as already completed synchronously.
    /// </summary>
    /// <param name="completable">The operation to mark.</param>
    /// <param name="result">The result of the operation.</param>
    /// <returns><paramref name="completable"/> for fluent-style use.</returns>
    public static TCompletable Complete<TCompletable, TResult>(this TCompletable completable, TResult? result)
        where TCompletable : ICompletableWithResult<TResult>
        where TResult : class
    {
        completable.Result = result;
        return completable.Complete();
    }
}