MonoScriptCache.cs

using System;
using System.Collections.Generic;
using UnityEditor;

namespace NGToolsEditor.NGMissingScriptRecovery
{
	using UnityEngine;

	public static class MonoScriptCache
	{
		private static Dictionary<Type, MonoScriptIdentity>	cache = new Dictionary<Type, MonoScriptIdentity>();

		public static MonoScriptIdentity	Get(Type type)
		{
			MonoScriptIdentity	result;

			if (MonoScriptCache.cache.TryGetValue(type, out result) == false)
			{
				result = new MonoScriptIdentity();

				MonoScript	monoScript;

				if (typeof(ScriptableObject).IsAssignableFrom(type) == true)
				{
					ScriptableObject	temp = ScriptableObject.CreateInstance(type);
					monoScript = MonoScript.FromScriptableObject(temp);
					Object.DestroyImmediate(temp, true);
				}
				else
				{
					GameObject	temp = new GameObject("TEMP_RECOVERY", type);
					monoScript = MonoScript.FromMonoBehaviour(temp.GetComponent(type) as MonoBehaviour);
					Object.DestroyImmediate(temp, true);
				}

				if (monoScript == null)
					return result;

#if UNITY_2018_2_OR_NEWER
				// Modern technique, fastest & safest.
				AssetDatabase.TryGetGUIDAndLocalFileIdentifier(monoScript.GetInstanceID(), out result.guid, out result.localID);
#endif

				// First fallback, quick, can fix a Type from a DLL.
				if (result.guid == null || result.guid.Length != 32 || result.localID == 0)
				{
					using (SerializedObject serializedScript = new SerializedObject(monoScript))
					{
						BrokenObject.inspectorModeProperty.SetValue(serializedScript, InspectorMode.Debug);
						result.localID = serializedScript.FindProperty("m_LocalIdentfierInFile").intValue;
					}

					string	projectPath = System.IO.Path.GetFullPath(Application.dataPath);

					if (type.Assembly.Location.StartsWith(projectPath) == true)
						result.guid = AssetDatabase.AssetPathToGUID(type.Assembly.Location.Substring(projectPath.Length - "Assets".Length).Replace('\\', '/'));
					else
						result.guid = AssetDatabase.AssetPathToGUID(type.Assembly.Location);
				}

				// Second fallback, slower, works as long as the Type's name matches the C# filename in the project.
				if (result.guid == null || result.guid.Length != 32 || result.localID == 0)
				{
					string[]	files = AssetDatabase.FindAssets(type.Name + " t:MonoScript");

					for (int i = 0, max = files.Length; i < max; ++i)
					{
						string	path = AssetDatabase.GUIDToAssetPath(files[i]);

						if (path.EndsWith("/" + type.Name + ".cs") == true)
						{
							MonoScript	ms = AssetDatabase.LoadAssetAtPath<MonoScript>(path);

							if (result.guid == null || result.guid.Length != 32)
								result.guid = files[i];

							if (result.localID == 0)
								result.localID = long.Parse(Utility.GetLocalIdentifierFromObject(ms));

							break;
						}
					}
				}

				Debug.AssertFormat(result.guid != null && result.guid.Length == 32 && result.localID != 0, "MonoScript identity for \"{0}\" could not be retrieve properly.", type);
				MonoScriptCache.cache.Add(type, result);
			}

			return result;
		}
	}
}