baseline: OpenMU upstream b5a0961 (fresh source)

src/PlugIns/StrategyPlugInProvider.cs

@@ -0,0 +1,108 @@
+// <copyright file="StrategyPlugInProvider.cs" company="MUnique">
+// Licensed under the MIT License. See LICENSE file in the project root for full license information.
+// </copyright>
+
+namespace MUnique.OpenMU.PlugIns;
+
+using System.Diagnostics.CodeAnalysis;
+using Microsoft.Extensions.Logging;
+
+/// <summary>
+/// The implementation for the <see cref="IStrategyPlugInProvider{TKey,TPlugIn}"/> which provides plugins by their key.
+/// </summary>
+/// <typeparam name="TKey">The type of the key.</typeparam>
+/// <typeparam name="TPlugIn">The type of the plugin.</typeparam>
+/// <seealso cref="MUnique.OpenMU.PlugIns.IStrategyPlugInProvider{TKey, TPlugIn}" />
+/// <seealso cref="IPlugInContainer{TPlugIn}" />
+public class StrategyPlugInProvider<TKey, TPlugIn> : PlugInContainerBase<TPlugIn>, IStrategyPlugInProvider<TKey, TPlugIn>
+    where TPlugIn : class, IStrategyPlugIn<TKey>
+    where TKey : notnull
+{
+    private readonly IDictionary<TKey, TPlugIn> _effectiveStrategies = new Dictionary<TKey, TPlugIn>();
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="StrategyPlugInProvider{TKey, TPlugIn}" /> class.
+    /// </summary>
+    /// <param name="manager">The plugin manager that manages this instance.</param>
+    /// <param name="loggerFactory">The logger factory.</param>
+    public StrategyPlugInProvider(PlugInManager manager, ILoggerFactory loggerFactory)
+        : base(manager)
+    {
+        this.Logger = loggerFactory.CreateLogger(this.GetType());
+    }
+
+    /// <inheritdoc />
+    public IEnumerable<TPlugIn> AvailableStrategies
+    {
+        get
+        {
+            using var l = this.Lock.ReaderLock();
+            return this._effectiveStrategies.Values.ToList();
+        }
+    }
+
+    /// <summary>
+    /// Gets the logger.
+    /// </summary>
+    /// <value>
+    /// The logger.
+    /// </value>
+    protected ILogger Logger { get; }
+
+    /// <inheritdoc />
+    public TPlugIn? this[TKey key]
+    {
+        get
+        {
+            using var l = this.Lock.ReaderLock();
+            if (this.TryGetPlugIn(key, out var plugIn))
+            {
+                return plugIn;
+            }
+
+            return default;
+        }
+    }
+
+    /// <summary>
+    /// Tries the get the plug in with the specified key.
+    /// </summary>
+    /// <param name="key">The key.</param>
+    /// <param name="plugIn">The plugin.</param>
+    /// <returns><c>True</c>, if the plugin has been found and returned; Otherwise, <c>false</c>.</returns>
+    protected bool TryGetPlugIn(TKey key, [MaybeNullWhen(false)] out TPlugIn plugIn) => this._effectiveStrategies.TryGetValue(key, out plugIn);
+
+    /// <inheritdoc />
+    protected override void ActivatePlugIn(TPlugIn plugIn)
+    {
+        base.ActivatePlugIn(plugIn);
+        if (this._effectiveStrategies.TryGetValue(plugIn.Key, out var registeredPlugIn))
+        {
+            this.Logger.LogWarning($"Plugin {registeredPlugIn} with key {plugIn.Key} was already registered and is active. Plugin {plugIn} will not be effective.");
+        }
+        else
+        {
+            this.SetEffectivePlugin(plugIn);
+        }
+    }
+
+    /// <inheritdoc />
+    protected override void DeactivatePlugIn(TPlugIn plugIn)
+    {
+        base.DeactivatePlugIn(plugIn);
+        if (this._effectiveStrategies.TryGetValue(plugIn.Key, out var effective) && effective == plugIn)
+        {
+            this._effectiveStrategies.Remove(plugIn.Key);
+        }
+    }
+
+    /// <summary>
+    /// Sets the effective plugin.
+    /// </summary>
+    /// <param name="plugIn">The plugin.</param>
+    protected void SetEffectivePlugin(TPlugIn plugIn)
+    {
+        this._effectiveStrategies.Remove(plugIn.Key);
+        this._effectiveStrategies.Add(plugIn.Key, plugIn);
+    }
+}