ILSpy/ILSpy/EntityReference.cs

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using System.Diagnostics;
using System.Reflection.Metadata;
using System.Reflection.Metadata.Ecma335;

using ICSharpCode.Decompiler.Metadata;
using ICSharpCode.Decompiler.TypeSystem;
using ICSharpCode.ILSpyX;

namespace ICSharpCode.ILSpy
{
	/// <summary>
	/// Unresolved metadata reference — a (module, handle) pair plus a protocol that says how
	/// to interpret the target (e.g. "decompile" jumps to the declaration in C# view).
	/// </summary>
	[DebuggerDisplay("EntityReference Module={Module}, Handle={Handle}, Protocol={Protocol}")]
	public sealed class EntityReference
	{
		readonly MetadataFile? metadataFile;
		public string Module { get; }
		public Handle Handle { get; }
		public string Protocol { get; }

		public EntityReference(string moduleFileName, Handle handle, string protocol = "decompile")
		{
			Module = moduleFileName;
			Handle = handle;
			Protocol = protocol;
		}

		public EntityReference(MetadataFile module, Handle handle, string protocol = "decompile")
		{
			metadataFile = module;
			Module = module.FileName;
			Handle = handle;
			Protocol = protocol;
		}

		public MetadataFile? ResolveAssembly(AssemblyList context)
			=> metadataFile ?? context.FindAssembly(Module)?.GetMetadataFileOrNull();

		/// <summary>
		/// Resolves this reference to a live <see cref="IEntity"/> within <paramref name="context"/>,
		/// or null when the module, the handle, or the entity can't be resolved. Builds a fresh
		/// uncached <see cref="DecompilerTypeSystem"/> per call -- the caller is resolving a single
		/// handle, not walking the whole module.
		/// </summary>
		public IEntity? Resolve(AssemblyList context)
		{
			var module = ResolveAssembly(context);
			if (module == null)
				return null;
			var token = MetadataTokenHelpers.TryAsEntityHandle(MetadataTokens.GetToken(Handle));
			if (token == null)
				return null;
			var typeSystem = new DecompilerTypeSystem(module, module.GetAssemblyResolver(),
				TypeSystemOptions.Default | TypeSystemOptions.Uncached);
			return typeSystem.MainModule.ResolveEntity(token.Value);
		}
	}
}