Umbraco-CMS/src/Umbraco.Core/Composing/FindAssembliesWithReferencesTo.cs

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

namespace Umbraco.Core.Composing
{
    /// <summary>
    /// Finds Assemblies from the entry point assemblies, it's dependencies and it's transitive dependencies that reference that targetAssemblyNames
    /// </summary>
    /// <remarkes>
    /// borrowed and modified from here https://github.com/dotnet/aspnetcore-tooling/blob/master/src/Razor/src/Microsoft.NET.Sdk.Razor/FindAssembliesWithReferencesTo.cs
    /// </remarkes>
    internal class FindAssembliesWithReferencesTo
    {
        private readonly Assembly[] _referenceAssemblies;
        private readonly string[] _targetAssemblies;
        private readonly bool _includeTargets;

        /// <summary>
        /// Constructor
        /// </summary>
        /// <param name="referenceAssemblies">Entry point assemblies</param>
        /// <param name="targetAssemblyNames">Used to check if the entry point or it's transitive assemblies reference these assembly names</param>
        /// <param name="includeTargets">If true will also use the target assembly names as entry point assemblies</param>
        public FindAssembliesWithReferencesTo(Assembly[] referenceAssemblies, string[] targetAssemblyNames, bool includeTargets)
        {
            _referenceAssemblies = referenceAssemblies;
            _targetAssemblies = targetAssemblyNames;
            _includeTargets = includeTargets;
        }

        public IEnumerable<Assembly> Find()
        {
            var referenceItems = new List<Assembly>();
            foreach (var assembly in _referenceAssemblies)
            {
                referenceItems.Add(assembly);
            }

            if (_includeTargets)
            {
                foreach(var target in _targetAssemblies)
                {
                    try
                    {
                        referenceItems.Add(Assembly.Load(target));
                    }
                    catch (FileNotFoundException)
                    {
                        // occurs if we cannot load this ... for example in a test project where we aren't currently referencing Umbraco.Web, etc...
                    }
                }
            }

            var provider = new ReferenceResolver(_targetAssemblies, referenceItems);
            var assemblyNames = provider.ResolveAssemblies();
            return assemblyNames.ToList();
        }

    }
}