Plugins can load assemblies from their dependent plugins (#6851)

BTCPayServer/Plugins/Dotnet/LibraryModel/ManagedLibrary.cs

@@ -0,0 +1,73 @@
+// Copyright (c) Nate McMaster.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Diagnostics;
+using System.IO;
+using System.Reflection;
+
+namespace BTCPayServer.Plugins.Dotnet.LibraryModel
+{
+    /// <summary>
+    /// Represents a managed, .NET assembly.
+    /// </summary>
+    [DebuggerDisplay("{Name} = {AdditionalProbingPath}")]
+    public class ManagedLibrary
+    {
+        private ManagedLibrary(AssemblyName name, string additionalProbingPath, string appLocalPath)
+        {
+            Name = name ?? throw new ArgumentNullException(nameof(name));
+            AdditionalProbingPath = additionalProbingPath ?? throw new ArgumentNullException(nameof(additionalProbingPath));
+            AppLocalPath = appLocalPath ?? throw new ArgumentNullException(nameof(appLocalPath));
+        }
+
+        /// <summary>
+        /// Name of the managed library
+        /// </summary>
+        public AssemblyName Name { get; private set; }
+
+        /// <summary>
+        /// Contains path to file within an additional probing path root. This is typically a combination
+        /// of the NuGet package ID (lowercased), version, and path within the package.
+        /// <para>
+        /// For example, <c>microsoft.data.sqlite/1.0.0/lib/netstandard1.3/Microsoft.Data.Sqlite.dll</c>
+        /// </para>
+        /// </summary>
+        public string AdditionalProbingPath { get; private set; }
+
+        /// <summary>
+        /// Contains path to file within a deployed, framework-dependent application.
+        /// <para>
+        /// For most managed libraries, this will be the file name.
+        /// For example, <c>MyPlugin1.dll</c>.
+        /// </para>
+        /// <para>
+        /// For runtime-specific managed implementations, this may include a sub folder path.
+        /// For example, <c>runtimes/win/lib/netcoreapp2.0/System.Diagnostics.EventLog.dll</c>
+        /// </para>
+        /// </summary>
+        public string AppLocalPath { get; private set; }
+
+        /// <summary>
+        /// Create an instance of <see cref="ManagedLibrary" /> from a NuGet package.
+        /// </summary>
+        /// <param name="packageId">The name of the package.</param>
+        /// <param name="packageVersion">The version of the package.</param>
+        /// <param name="assetPath">The path within the NuGet package.</param>
+        /// <returns></returns>
+        public static ManagedLibrary CreateFromPackage(string packageId, string packageVersion, string assetPath)
+        {
+            // When the asset comes from "lib/$tfm/", Microsoft.NET.Sdk will flatten this during publish based on the most compatible TFM.
+            // The SDK will not flatten managed libraries found under runtimes/
+            var appLocalPath = assetPath.StartsWith("lib/")
+                ? Path.GetFileName(assetPath)
+                : assetPath;
+
+            return new ManagedLibrary(
+                new AssemblyName(Path.GetFileNameWithoutExtension(assetPath)),
+                Path.Combine(packageId.ToLowerInvariant(), packageVersion, assetPath),
+                appLocalPath
+            );
+        }
+    }
+}