// 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 System;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.Host;

namespace Microsoft.CodeAnalysis.Shared.Utilities;

/// <summary>
/// An optional interface which allows an environment to customize the behavior for synchronous methods that need to
/// block on the result of an asynchronous invocation. An implementation of this is provided in the MEF catalog when
/// applicable.
/// </summary>
/// <remarks>
/// <para>For Visual Studio, Microsoft.VisualStudio.Threading provides the JoinableTaskFactory.Run method, which is
/// the expected way to invoke an asynchronous method from a synchronous entry point and block on its completion.
/// Other environments may choose to use this or any other strategy, or omit an implementation of this interface to
/// allow callers to simply use <see cref="Task.Wait()"/>.</para>
///
/// <para>New code is expected to use fully-asynchronous programming where possible. In cases where external APIs
/// restrict ability to be asynchronous, this service allows Roslyn to adhere to environmental policies related to
/// joining asynchronous work.</para>
/// </remarks>
internal interface IWorkspaceThreadingService
{
    bool IsOnMainThread { get; }

    TResult Run<TResult>(Func<Task<TResult>> asyncMethod);
}

internal interface IWorkspaceThreadingServiceProvider : IWorkspaceService
{
    IWorkspaceThreadingService Service { get; }
}