BepInEx/BepInEx.NetLauncher/Utility.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Reflection;

namespace BepInEx.NetLauncher
{
    /// <summary>
    ///     Generic helper properties and methods.
    /// </summary>
    public static class LocalUtility
    {
        /// <summary>
        ///     Try to resolve and load the given assembly DLL.
        /// </summary>
        /// <param name="assemblyName">Name of the assembly, of the type <see cref="AssemblyName" />.</param>
        /// <param name="directory">Directory to search the assembly from.</param>
        /// <param name="assembly">The loaded assembly.</param>
        /// <returns>True, if the assembly was found and loaded. Otherwise, false.</returns>
        private static bool TryResolveDllAssembly<T>(AssemblyName assemblyName,
                                                     string directory,
                                                     Func<string, T> loader,
                                                     out T assembly) where T : class
        {
            assembly = null;

            if (!Directory.Exists(directory))
                return false;

            var potentialDirectories = new List<string> { directory };

            potentialDirectories.AddRange(Directory.GetDirectories(directory, "*", SearchOption.AllDirectories));

            foreach (var subDirectory in potentialDirectories)
            {
                var path = Path.Combine(subDirectory, $"{assemblyName.Name}.dll");

                if (!File.Exists(path))
                    continue;

                try
                {
                    assembly = loader(path);
                }
                catch (Exception)
                {
                    continue;
                }

                return true;
            }

            return false;
        }

        /// <summary>
        ///     Try to resolve and load the given assembly DLL.
        /// </summary>
        /// <param name="assemblyName">Name of the assembly, of the type <see cref="AssemblyName" />.</param>
        /// <param name="directory">Directory to search the assembly from.</param>
        /// <param name="assembly">The loaded assembly.</param>
        /// <returns>True, if the assembly was found and loaded. Otherwise, false.</returns>
        public static bool TryResolveDllAssembly(AssemblyName assemblyName, string directory, out Assembly assembly) =>
            TryResolveDllAssembly(assemblyName, directory, Assembly.LoadFile, out assembly);
    }
}