Kerbal Space Program

// Kerbal Development tools.

// Author: [email protected]

// This software is distributed under Public domain license.

using System;

using System.Collections.Generic;

using System.Reflection;

using UnityEngine;

[KSPAddon(KSPAddon.Startup.Instantly, true)]

public class AddonVersionDependancyBinder : MonoBehaviour {

  /// <summary>Local cache of redirects done so far. Used to speedup assembly resolutions since what

  /// has failed once will likely keep failing thru the game.</summary>

  static readonly Dictionary<string, Assembly> bindingRedirect = new Dictionary<string, Assembly>();

  void Awake() {

    // Ensure there is only one listener added.

    AppDomain.CurrentDomain.AssemblyResolve -= MyResolveEventHandler;

    AppDomain.CurrentDomain.AssemblyResolve += MyResolveEventHandler;

  }

  /// <summary>Triggers when framework fails to resolve an assembly.</summary>

  /// <remarks>Since KSP versioning engine verifies addons dependencies this failure may only happen

  /// if a dependency assembly has been upgarded to a higher version. This code tries to load the

  /// assembly without version specified, and just checks if the found assembly has greater version.

  /// <param name="sender"></param>

  /// <param name="args"></param>

  /// <returns></returns>

  static Assembly MyResolveEventHandler(object sender, ResolveEventArgs args) {

    // Return cached version if exists.

    Assembly result = null;

    if (bindingRedirect.TryGetValue(args.Name, out result)) {

      return result;

    }

    // Try finding asssembly by name ignoring the version info. 

    var targetAssemblyName = new AssemblyName(args.Name);

    var targetAssemblyVersion = targetAssemblyName.Version;

    targetAssemblyName.Version = null;

    try {

      result = Assembly.Load(targetAssemblyName);

      if (result.GetName().Version >= targetAssemblyVersion) {

        Debug.LogFormat("ADDON BINDER: Create binding redirect: {0} => {1}",

                        args.Name, result.FullName);

      } else {

        Debug.LogWarningFormat(

            "ADDON BINDER: Ingoring binding redirect due to incompatible versions: {0} => {1}",

            args.Name, result.FullName);

        result = null;

      }

    } catch (Exception) {

      Debug.LogErrorFormat("ADDON BINDER: Cannot resolve assembly: {0}", targetAssemblyName);

    }

    bindingRedirect.Add(args.Name, result);

    return result;

  }

}