Unity開發(fā)時自動熱更新Lua代碼

在游戲開發(fā)階段中提鸟，經(jīng)常需要小修小改，Unity提供了很方便的Scene窗口仅淑，讓開發(fā)者的修改馬上生效称勋，而不需要重新啟動游戲。
那么代碼需要怎么樣才能做到一修改就馬上生效涯竟，并且不需要重啟游戲呢赡鲜？

下面結合Slua來說一下代碼自動更新的方案(我使用的版本是slua-1.3.2空厌，較舊)

思路：

獲取Lua加載過哪些文件揩瞪，記錄下這些文件的文件名喷屋、全路徑和最后修改時間
定時檢測文件的最后修改時間密任，如果比記錄的最后修改時間還要大淹遵，則表示在加載后發(fā)生過修改，然后重新加載它

代碼：

using UnityEngine;
#if UNITY_EDITOR    
using UnityEditor;
#endif
using System.Collections;
using System.Collections.Generic;
using System.IO;
using SLua;
using System;

namespace XS
{
    public class ImmediateLuaScript : MonoBehaviour
    {
        public class ScriptInfo
        {
            public string strFileName;
            public string strFileFullPath;
            public System.DateTime dtLastWrite;
        }

        List<ScriptInfo> m_loadedScripts = new List<ScriptInfo>();
        int m_nNextScriptIndex = 0;

        private static ImmediateLuaScript _Instance;
        public static ImmediateLuaScript Instance
        {
            get
            {
                if (_Instance == null)
                {
                    GameObject resMgr = GameObject.Find("_ImmediateLuaScript");
                    if (resMgr == null)
                    {
                        resMgr = new GameObject("_ImmediateLuaScript");
                        GameObject.DontDestroyOnLoad(resMgr);
                    }

                    _Instance = resMgr.AddComponent<ImmediateLuaScript>();
                }
                return _Instance;
            }
        }

#if UNITY_EDITOR
       // 可以通過外部控制ImmediateLuaScriptInEditor老玛，使自動更新暫团澹或恢復
       public static bool ImmediateLuaScriptInEditor = true;
       // 每幀檢查文件數(shù)，可根據(jù)文件數(shù)量成正比
       public static int CheckFilesOnce = 5;

       ScriptInfo getScriptInfo(string strFileFullPath)
        {
            foreach (ScriptInfo info in m_loadedScripts)
            {   
                if(info.strFileFullPath == strFileFullPath)
                {
                    return info;
                }
            }
            return null;
        }

        ScriptInfo getOrCreateScriptInfo(string strFileName, string strFileFullPath)
        {
            ScriptInfo info = getScriptInfo(strFileFullPath);
            if (info != null) return info;

            info = new ScriptInfo();
            info.strFileName = strFileName;
            info.strFileFullPath = strFileFullPath;
            m_loadedScripts.Add(info);
            return info;
        }

        ScriptInfo getNextScriptInfo()
        {
            if (m_nNextScriptIndex >= m_loadedScripts.Count)
            {
                m_nNextScriptIndex = 0;
                return null;
            }

            return m_loadedScripts[m_nNextScriptIndex++];
        }

        string getFileFullPath(string strFileName)
        {
            string strFileFullPath;
            do
            {
                // 這里的代碼目錄路徑屬于自定義
                strFileFullPath = UnityEngine.Application.dataPath + "/../luaScript/" + strFileName + ".lua";
                if (System.IO.File.Exists(strFileFullPath))
                    break;
            } while (false);

            return strFileFullPath;
        }

        public void SetImmediateLuaScript(string strFileName)
        {
            if (!ImmediateLuaScriptInEditor) return;

            string strFileFullPath = getFileFullPath(strFileName);
            FileInfo fileInfo = new FileInfo(strFileFullPath);
            if(fileInfo.Exists)
            {
                ScriptInfo info = getOrCreateScriptInfo(strFileName, strFileFullPath);
                info.dtLastWrite = fileInfo.LastWriteTime;
            }
        }

        void checkScriptUpdate()
        {
            ScriptInfo info = getNextScriptInfo();
            if (info == null) return;

            FileInfo fileInfo = new FileInfo(info.strFileFullPath);
            if (info.dtLastWrite < fileInfo.LastWriteTime)
            {
                info.dtLastWrite = fileInfo.LastWriteTime;
                bool result = loadScriptFile(info.strFileName, info.strFileFullPath);
                if(!result)
                {
                    var L = LuaSvr.Instance.luaState.L;
                    string err = LuaDLL.lua_tostring(L, -1);
                    LuaDLL.lua_pop(L, 2);
                    throw new Exception(err);
                }
            }
        }

        void LateUpdate()
        {
            if (!ImmediateLuaScriptInEditor) return;
            for(int i=0;i<CheckFilesOnce; i++)
            {
                checkScriptUpdate();
            }
        }

        public static int newLoader(System.IntPtr L)
        {
            string fileName = LuaDLL.lua_tostring(L, 1);
            Instance.SetImmediateLuaScript(fileName);
            LuaObject.pushValue(L, true);
            LuaDLL.lua_pushnil(L);
            return 2;
        }

        // 注冊Lua腳本loader
        public void AddLuaLoaders(System.IntPtr L)
        {
            LuaState.pushcsfunction(L, newLoader);
            int loaderFunc = LuaDLL.lua_gettop(L);

            LuaDLL.lua_getglobal(L, "package");
#if LUA_5_3
            LuaDLL.lua_getfield(L, -1, "searchers");
#else
            LuaDLL.lua_getfield(L, -1, "loaders");
#endif
            int loaderTable = LuaDLL.lua_gettop(L);

            // Shift table elements right
            for (int e = LuaDLL.lua_rawlen(L, loaderTable) + 1; e > 2; e--)
            {
                LuaDLL.lua_rawgeti(L, loaderTable, e - 1);
                LuaDLL.lua_rawseti(L, loaderTable, e);
            }
            LuaDLL.lua_pushvalue(L, loaderFunc);
            LuaDLL.lua_rawseti(L, loaderTable, 2);
            LuaDLL.lua_settop(L, 0);
        }

        // 加載lua文件
        bool loadScriptFile(string strFileName, string strFileFullPath)
        {
            FileStream fs = new FileStream(strFileFullPath, FileMode.Open);
            long size = fs.Length;
            byte[] bytes = new byte[size];
            fs.Read(bytes, 0, bytes.Length);
            fs.Close();

            bytes = LuaState.CleanUTF8Bom(bytes);

            var L = LuaSvr.Instance.luaState.L;
            if (bytes != null)
            {
                var nOldTop = LuaDLL.lua_gettop(L);
                var err = LuaDLL.luaL_loadbuffer(L, bytes, bytes.Length, "@" + strFileFullPath);
                if (err != 0)
                {
                    string errstr = LuaDLL.lua_tostring(L, -1);
                    LuaDLL.lua_pop(L, 1);
                    LuaObject.error(L, errstr);
                    return false;
                }
                err = LuaDLL.lua_pcall(L, 0, 0, 0);
                if (err != 0)
                {
                    string errstr = LuaDLL.lua_tostring(L, -1);
                    LuaDLL.lua_pop(L, 1);
                    LuaObject.error(L, errstr);
                    return false;
                }
                LuaDLL.lua_settop(L, nOldTop);
                Debug.Log(" *** Reload Lua File Successful : " + strFileName);
                return true;
            }
            LuaObject.error(L, "Can't find {0}", strFileFullPath);
            return false;
        }

#endif

    }
}

使用：

在Slua啟動時薪前，在任何未加載Lua腳本前調(diào)用

    ImmediateLuaScript.Instance.AddLuaLoaders(luaState.L);

來完成注冊

注意事項：

熱更新Lua代碼只是針對具體文件依次執(zhí)行l(wèi)uaL_loadbuffer和lua_pcall鳍侣，并不能更新代碼中的閉包
代碼中的局部變量會丟失，所以需要在代碼書寫時注意局部變量的保存（這里涉及Lua框架設計敛助，如setfenv测砂、module加匈、_ENV存璃，甚至面向對象）
可以通過增大CheckFilesOnce來加快檢測速度，但是這樣會影響到游戲運行時的性能
每次更新代碼后會在后臺輸出 “ *** Reload Lua File Successful : FileName ”