在Unity编辑器中搜索资源的引用关系

优化游戏的时候，我们需要删除没有用到的资源。如何判断资源有没有被引用？
Unity编辑器提供了两个搜索资源关系的方法：
（1）Find References In Scene，在Hierarchy面板中搜索资源的引用关系
（2）Select Dependencies，在Project面板中搜索资源的依赖关系
但是这两个方法并不能满足我们的需求，因此我写了另外一个搜索资源引用的方法：
原理很简单：
（1）获取当前文件的guid
（2）获取所有查找文件的内容
（3）判断这些文件内容包不包含这个guid

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEditor;
using System.IO;
using System.Text;

public class ReferenceEditor : Editor
{
    [MenuItem ("Assets/Find References In Prefabs", false, 50)]
    private static void FindReferencesInPrefabs ()
    {
        FindReferences("*.prefab");
    }

    [MenuItem ("Assets/Find References In Prefabs", true)]
    private static bool ValidateFindReferencesInPrefabs ()
    {
        return Selection.activeObject != null;
    }

    [MenuItem ("Assets/Find References In Materials", false, 50)]
    private static void FindReferencesInMaterials ()
    {
        FindReferences("*.mat");
    }

    [MenuItem ("Assets/Find References In Materials", true)]
    private static bool ValidateFindReferencesInMaterials ()
    {
        return Selection.activeObject != null;
    }

    [MenuItem ("Assets/Find References In Configs", false, 50)]
    private static void FindReferencesInConfigs ()
    {
        FindReferences("*.asset");
    }

    [MenuItem ("Assets/Find References In Configs", true)]
    private static bool ValidateFindReferencesInConfigs ()
    {
        return Selection.activeObject != null;
    }

    [MenuItem ("Assets/Find References In SpriteAtlas", false, 50)]
    private static void FindReferencesInSpriteAtlas ()
    {
        FindReferences("*.spriteatlas");
    }

    [MenuItem ("Assets/Find References In SpriteAtlas", true)]
    private static bool ValidateFindReferencesInSpriteAtlas ()
    {
        return Selection.activeObject != null;
    }

    private static List<string> prefabList;
    private static List<string> guidList;
    private static List<string> pathList;
    private static Dictionary<string, List<string>> referDict = new Dictionary<string, List<string>>();

    private static void FindReferences(string pattern)
    {
        guidList = new List<string>(Selection.assetGUIDs);
        pathList = new List<string>();
        for(int i=0; i<guidList.Count; ++i) {
            pathList.Add(AssetDatabase.GUIDToAssetPath(guidList[i]));
        }

        GetFilesWithPattern(pattern);
        
        CheckEveryPrefab();
    }

    private static void GetFilesWithPattern(string pattern)
    {
        string[] prefabArr = GetFiles(Application.dataPath, pattern);
        prefabList = new List<string>(prefabArr);
    }

    private static string[] GetFiles(string folderPath, string pattern, bool recursive = true)
    {
        List<string> pathList = new List<string>();
        string[] dirArr = Directory.GetFiles(folderPath, pattern, recursive ? SearchOption.AllDirectories : SearchOption.TopDirectoryOnly);
        for (int i=0; i<dirArr.Length; ++i)
        {
            if(Path.GetExtension(dirArr[i]) != ".meta")
                pathList.Add(dirArr[i].Replace('\\', '/'));
        }
        return pathList.ToArray();
    }

    private static void CheckEveryPrefab()
    {
        if(guidList == null || guidList.Count == 0)
            return;
        
        if(prefabList == null || prefabList.Count == 0)
            return;

        referDict.Clear();
        for(int i=0; i<guidList.Count; ++i)
        {
            for(int j=0; j<prefabList.Count; ++j)
            {
                EditorUtility.DisplayProgressBar("搜索预设引用关系", "搜索中..." + pathList[i], j / prefabList.Count);
                FileStream fs = new FileStream(prefabList[j], FileMode.Open, FileAccess.Read);
                byte[] buff = new byte[fs.Length];
                fs.Read(buff, 0, (int)fs.Length);
                string strText = Encoding.Default.GetString(buff);
                int index = strText.IndexOf(guidList[i]);
                if(index != -1)
                {
                    Debug.Log(pathList[i] + " : " + prefabList[j].Replace(Application.dataPath, ""));
                }
            }
        }
        EditorUtility.ClearProgressBar();
    }
}