8 files changed, 242 insertions(+), 0 deletions(-)

A src/Extensions/NosSmooth.Extensions.SharedBinding/EventArgs/ConflictEventArgs.cs
A src/Extensions/NosSmooth.Extensions.SharedBinding/EventArgs/InstanceEventArgs.cs
M src/Extensions/NosSmooth.Extensions.SharedBinding/Extensions/ServiceCollectionExtensions.cs
A src/Extensions/NosSmooth.Extensions.SharedBinding/Lifetime/DefaultInstanceLifetime.cs
A src/Extensions/NosSmooth.Extensions.SharedBinding/Lifetime/IInstanceLifetime.cs
A src/Extensions/NosSmooth.Extensions.SharedBinding/Lifetime/SharedInstanceInfo.cs
A src/Extensions/NosSmooth.Extensions.SharedBinding/Lifetime/SharedLifetime.cs
M src/Extensions/NosSmooth.Extensions.SharedBinding/SharedManager.cs

@@ 0,0 1,60 @@
+//
+//  ConflictEventArgs.cs
+//
+//  Copyright (c) František Boháček. All rights reserved.
+//  Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using NosSmooth.Extensions.SharedBinding.Lifetime;
+
+namespace NosSmooth.Extensions.SharedBinding.EventArgs;
+
+/// <summary>
+/// Arguments containing information about a shared instance.
+/// The conflict may be resolved by setting the correct property.
+/// </summary>
+public class ConflictEventArgs : System.EventArgs
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="ConflictEventArgs"/> class.
+    /// </summary>
+    /// <param name="conflictingInstances">All of the conflicting instances.</param>
+    /// <param name="defaultResolution">The default method to resolve the conflict.</param>
+    public ConflictEventArgs(IReadOnlyList<SharedInstanceInfo> conflictingInstances, ConflictResolution defaultResolution)
+    {
+        ConflictingInstances = conflictingInstances;
+        Resolve = defaultResolution;
+    }
+
+    /// <summary>
+    /// Gets the instances that are in conflict.
+    /// </summary>
+    public IReadOnlyList<SharedInstanceInfo> ConflictingInstances { get; }
+
+    /// <summary>
+    /// Gets or sets the method of resolution.
+    /// </summary>
+    public ConflictResolution Resolve { get; set; }
+
+    /// <summary>
+    /// Possible methods of resolution.
+    /// </summary>
+    public enum ConflictResolution
+    {
+        /// <summary>
+        /// Allow the new instance, keep the old ones.
+        /// </summary>
+        Allow,
+
+        /// <summary>
+        /// Do not allow the new instance, keep the old ones.
+        /// </summary>
+        Restrict,
+
+        /// <summary>
+        /// Allow the instance, try to detach the old instance.
+        /// In case the old instance cannot be detached, fall back
+        /// to <see cref="Restrict"/>.
+        /// </summary>
+        DetachOriginal
+    }
+}<
\ No newline at end of file

@@ 0,0 1,29 @@
+//
+//  InstanceEventArgs.cs
+//
+//  Copyright (c) František Boháček. All rights reserved.
+//  Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using NosSmooth.Extensions.SharedBinding.Lifetime;
+
+namespace NosSmooth.Extensions.SharedBinding.EventArgs;
+
+/// <summary>
+/// Arguments containing information about a shared instance.
+/// </summary>
+public class InstanceEventArgs : System.EventArgs
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="InstanceEventArgs"/> class.
+    /// </summary>
+    /// <param name="instanceInfo">The new instance.</param>
+    public InstanceEventArgs(SharedInstanceInfo instanceInfo)
+    {
+        InstanceInfo = instanceInfo;
+    }
+
+    /// <summary>
+    /// Gets the information about the new instance.
+    /// </summary>
+    public SharedInstanceInfo InstanceInfo { get; }
+}<
\ No newline at end of file

@@ 5,10 5,12 @@
 //  Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
 using System.Diagnostics;
+using System.Reflection;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.DependencyInjection.Extensions;
 using NosSmooth.Data.NOSFiles;
 using NosSmooth.Extensions.SharedBinding.Hooks;
+using NosSmooth.Extensions.SharedBinding.Lifetime;
 using NosSmooth.LocalBinding;
 using NosSmooth.LocalBinding.Extensions;
 using NosSmooth.LocalBinding.Hooks;


@@ 94,7 96,9 @@ public static class ServiceCollectionExtensions
     /// <returns>The same collection.</returns>
     public static IServiceCollection ShareNosSmooth(this IServiceCollection serviceCollection)
     {
+        var assembly = Assembly.GetCallingAssembly();
         return serviceCollection
+            .AddSingleton(_ => new SharedInstanceInfo(assembly.GetName().FullName, assembly.GetName().Version?.ToString(), assembly))
             .AddSingleton<SharedManager>(p => SharedManager.Instance)
             .ShareHooks()
             .TryShare<NosBrowserManager>()

@@ 0,0 1,57 @@
+//
+//  DefaultInstanceLifetime.cs
+//
+//  Copyright (c) František Boháček. All rights reserved.
+//  Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using Remora.Results;
+
+namespace NosSmooth.Extensions.SharedBinding.Lifetime;
+
+public class DefaultInstanceLifetime : IInstanceLifetime
+{
+    private readonly CancellationTokenSource _stoppingSource;
+    private bool _stoppingHooked;
+
+    public DefaultInstanceLifetime()
+    {
+        _stoppingSource = new CancellationTokenSource();
+    }
+
+    /// <inheritdoc/>
+    public SharedInstanceInfo Info { get; }
+
+    /// <inheritdoc />
+    public CancellationToken InstanceStopping
+    {
+        get
+        {
+            _stoppingHooked = true;
+            return _stoppingSource.Token;
+        }
+    }
+
+    /// <inheritdoc />
+    public Result RequestStop()
+    {
+        if (!_stoppingHooked)
+        { // There is no way anything was hooked to InstanceStopping, thus
+          // stop won't work for sure.
+            return new CannotRequestStop()
+        }
+
+        try
+        {
+            _stoppingSource.Cancel();
+            return Result.FromSuccess();
+        }
+        catch (TaskCanceledException)
+        {
+            return Result.FromSuccess();
+        }
+        catch (Exception e)
+        {
+            return e;
+        }
+    }
+}<
\ No newline at end of file

@@ 0,0 1,20 @@
+//
+//  IInstanceLifetime.cs
+//
+//  Copyright (c) František Boháček. All rights reserved.
+//  Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using Remora.Results;
+
+namespace NosSmooth.Extensions.SharedBinding.Lifetime;
+
+public interface IInstanceLifetime
+{
+    public SharedInstanceInfo Info { get; }
+
+    public CancellationToken InstanceStopping { get; }
+
+    public CancellationToken InstanceStopped { get; }
+
+    public Task<Result> RequestStop();
+}<
\ No newline at end of file

@@ 0,0 1,11 @@
+//
+//  SharedInstanceInfo.cs
+//
+//  Copyright (c) František Boháček. All rights reserved.
+//  Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System.Reflection;
+
+namespace NosSmooth.Extensions.SharedBinding.Lifetime;
+
+public record SharedInstanceInfo(string Name, string? Version, Assembly Assembly);

@@ 0,0 1,53 @@
+//
+//  SharedLifetime.cs
+//
+//  Copyright (c) František Boháček. All rights reserved.
+//  Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using NosSmooth.Extensions.SharedBinding.EventArgs;
+using Remora.Results;
+
+namespace NosSmooth.Extensions.SharedBinding.Lifetime;
+
+/// <summary>
+/// Events for shared lifetime.
+/// </summary>
+public class SharedLifetime
+{
+    /// <summary>
+    /// A new instance has been attached.
+    /// </summary>
+    public event EventHandler<InstanceEventArgs>? InstanceAttached;
+
+    /// <summary>
+    /// A new instance has been attached and a conflict was detected,
+    /// the same instance type is already attached.
+    /// </summary>
+    public event EventHandler<ConflictEventArgs>? ConflictDetected;
+
+    /// <summary>
+    /// Initialize a new shared instance.
+    /// </summary>
+    /// <param name="instanceInfo">The new instance.</param>
+    /// <returns>A result, if errorful, the new instance should not start.</returns>
+    public Result<CancellationTokenSource> Initialize(SharedInstanceInfo instanceInfo)
+    {
+        return Result<CancellationTokenSource>.FromSuccess(new CancellationTokenSource());
+    }
+
+    /// <summary>
+    /// Initialize a new shared instance without its cooperation.
+    /// In case the instance is not allowed, an exception will be thrown.
+    /// </summary>
+    /// <param name="instanceInfo">The shared instance.</param>
+    /// <exception cref="Exception">Throws an exception in case the instance cannot be attached.</exception>
+    public void ForceInitialize(SharedInstanceInfo instanceInfo)
+    {
+        var result = Initialize(instanceInfo);
+
+        if (!result.IsSuccess)
+        {
+            throw new Exception($"Initialization not allowed! {result.Error.Message}");
+        }
+    }
+}<
\ No newline at end of file

@@ 7,6 7,7 @@
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Options;
 using NosSmooth.Data.NOSFiles;
+using NosSmooth.Extensions.SharedBinding.Lifetime;
 using NosSmooth.LocalBinding;
 using NosSmooth.PacketSerializer.Packets;
 


@@ 41,9 42,15 @@ public class SharedManager
 
     private SharedManager()
     {
+        Lifetime = new SharedLifetime();
     }
 
     /// <summary>
+    /// Gets the shared lifetime.
+    /// </summary>
+    public SharedLifetime Lifetime { get; }
+
+    /// <summary>
     /// Get shared equivalent of the given type.
     /// </summary>
     /// <param name="services">The service provider.</param>


@@ 53,6 60,7 @@ public class SharedManager
     public T GetShared<T>(IServiceProvider services)
         where T : class
     {
+        Lifetime.ForceInitialize(services.GetRequiredService<SharedInstanceInfo>());
         if (!_sharedData.ContainsKey(typeof(T)))
         {
             _sharedData[typeof(T)] = CreateShared<T>(services);