/// <summary>
/// Search all fallback paths for a suitable .dll ignoring all exceptions.
/// Returns the full path to the dll if a suitable assembly was found.
/// </summary>
private string?ResolveFromFallbackPaths(AssemblyName name)
{
bool MatchByName(string file) =>
Path.GetFileNameWithoutExtension(file)
.Equals(name.Name, StringComparison.InvariantCultureIgnoreCase);
var found = new List <string>();
foreach (var dir in this.fallbackPaths)
{
try
{
found.AddRange(Directory.GetFiles(dir, "*.dll", SearchOption.AllDirectories).Where(MatchByName));
}
catch
{
continue;
}
}
if (found.Count <= 1 || name.Version == null)
{
return(found.FirstOrDefault());
}
var tempContext = new LoadContext(this.PathToParentAssembly);
var versions = new List <(string, Version?)>();
foreach (var file in found)
{
try
{
var asm = tempContext.LoadFromAssemblyPath(file);
var asmVersion = asm.GetName()?.Version;
versions.Add((file, asmVersion));
if (name.Version.Equals(asmVersion))
{
if (tempContext.IsCollectible)
{
tempContext.Unload();
}
return(file);
}
}
catch
{
continue;
}
}
if (tempContext.IsCollectible)
{
tempContext.Unload();
}
var matchesMajor = versions.Where(asm => name.Version.Major == asm.Item2?.Major);
var matchesMinor = matchesMajor.Where(asm => name.Version.Minor == asm.Item2?.Minor);
var matchesMajRev = matchesMinor.Where(asm => name.Version.MajorRevision == asm.Item2?.MajorRevision);
return(matchesMajRev.Concat(matchesMinor).Concat(matchesMajor).Select(asm => asm.Item1).FirstOrDefault());
}
/// <summary>
/// Loads an assembly at the given location into a new context.
/// Adds the specified fallback locations, if any,
/// to the list of paths where the context will try to look for assemblies that could otherwise not be loaded.
/// Throws a FileNotFoundException if no file with the given path exists.
/// </summary>
public static Assembly LoadAssembly(string path, string[] fallbackPaths = null)
{
if (!File.Exists(path))
{
throw new FileNotFoundException("Failed to create contex for \"path\". No such file exists.");
}
var context = new LoadContext(path);
if (fallbackPaths != null)
{
context.AddToPath(fallbackPaths);
}
LoadContext.Loaded.Add(context);
var assemblyName = new AssemblyName(Path.GetFileNameWithoutExtension(path));
return(context.LoadFromAssemblyName(assemblyName));
}