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

BTCPayServer/Plugins/Dotnet/LibraryModel/NativeLibrary.cs

@@ -0,0 +1,69 @@
+// 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;
+
+namespace BTCPayServer.Plugins.Dotnet.LibraryModel
+{
+    /// <summary>
+    /// Represents an unmanaged library, such as `libsqlite3`, which may need to be loaded
+    /// for P/Invoke to work.
+    /// </summary>
+    [DebuggerDisplay("{Name} = {AdditionalProbingPath}")]
+    public class NativeLibrary
+    {
+        private NativeLibrary(string name, string appLocalPath, string additionalProbingPath)
+        {
+            Name = name ?? throw new ArgumentNullException(nameof(name));
+            AppLocalPath = appLocalPath ?? throw new ArgumentNullException(nameof(appLocalPath));
+            AdditionalProbingPath = additionalProbingPath ?? throw new ArgumentNullException(nameof(additionalProbingPath));
+        }
+
+        /// <summary>
+        /// Name of the native library. This should match the name of the P/Invoke call.
+        /// <para>
+        /// For example, if specifying `[DllImport("sqlite3")]`, <see cref="Name" /> should be <c>sqlite3</c>.
+        /// This may not match the exact file name as loading will attempt variations on the name according
+        /// to OS convention. On Windows, P/Invoke will attempt to load `sqlite3.dll`. On macOS, it will
+        /// attempt to find `sqlite3.dylib` and `libsqlite3.dylib`. On Linux, it will attempt to find
+        /// `sqlite3.so` and `libsqlite3.so`.
+        /// </para>
+        /// </summary>
+        public string Name { get; private set; }
+
+        /// <summary>
+        /// Contains path to file within a deployed, framework-dependent application
+        /// <para>
+        /// For example, <c>runtimes/linux-x64/native/libsqlite.so</c>
+        /// </para>
+        /// </summary>
+        public string AppLocalPath { 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>sqlite/3.13.3/runtimes/linux-x64/native/libsqlite.so</c>
+        /// </para>
+        /// </summary>
+        public string AdditionalProbingPath { get; private set; }
+
+        /// <summary>
+        /// Create an instance of <see cref="NativeLibrary" /> 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 NativeLibrary CreateFromPackage(string packageId, string packageVersion, string assetPath)
+        {
+            return new NativeLibrary(
+                Path.GetFileNameWithoutExtension(assetPath),
+                assetPath,
+                Path.Combine(packageId.ToLowerInvariant(), packageVersion, assetPath)
+            );
+        }
+    }
+}