xLua介绍

xLua地址：传送门

Xlua是啥？
2016年腾讯推出的一种 unity下 lua 编成的解决方案

基本概念介绍：
1.模块
模块就是一个 程序库，可以通过 require 加载，得到了一个表示 table的全局变量
这个table 就像一个命名空间，他的内容就是模块中导出的所有东西，比如：函数和常量

2.require 函数
Lua 提供了一个名为 require 的函数来加载模块。
执行 require 后会返回一个由模块常量或函数组成的 table，并且还会定义一个包含该 table 的全局变量
将模块中旧的函数替换成新的函数，这个新的函数可以放到一个Lua文件

3.upvalue与闭包
Lua函数可以被当成参数传递，可以被当成结果返回，在函数体中仍然可以定义内嵌函数
Lua闭包是Lua函数生成的数据对象。每个闭包可以有一个upvalue值，或者多个闭包共享一个upvalue数值
（如果函数F2定义在函数F1中，那么函数F2为F1的内嵌函数，F1为F2的外包函数）
内嵌函数可以访问外包函数已经创建的局部变量，而这些局部变量则被称为该内嵌函数的外部局部变量（或者upvalue）

4.require实现热更新
Lua 的 require(modelname) 把一个lua文件加载存放到 package.load[modelname]
当我们加载一个模块的时候，会先判断是否在package.loaded中已存在，如果存在就直接返回，不存在才加载，防止重复加载

通过AddLoader可以注册个回调，该回调参数是字符串
lua代码调用require时，参数将会透传给回调，回调中可以根据这个参数取加载指定文件
返回一个byte数组，如果为空则表示该loader找不到，否则则为lua文件内容

public class CustomLoader : Monobehaviour
{LuaEnv luaenv = null;void Start(){luaenv = new LuaEnv();luaenv.AddLoader((ref string filename) =>{return xxxx;});}
}

5.xLua使用流程
如图所示：

流程：
1.xLua文件配置：通过对C#的类与函数设置Hotfix标签。来标识需要支持热更的类和函数

a.打标签：
xLua用白名单来指明生成哪些代码，而白名单通过attribute来配置
（比如想从lua调用c#的某个类，希望生成适配代码，可以加一个 LuaCallCSharp 标签）
注意：会在il2cpp下增加不少代码量，不建议使用

[LuaCallCSharp]
public classA
{
}

b.静态列表
有时候不能给一个类型打标签（比如系统的API，没源码的库，或者实例化的泛型类型）
可以在一个静态类里声明一个静态字段，该字段的类型除 BlackList 和 AdditionalProperties 之外只要实现了 Ienumerable 就可以了

[LuaCallCSharp]
public static List<Type> my_lua_call_cs_list = new List<Type>()
{typeof(GameObject),typeof(Dictionary<string, int>)
};

c.动态列表
使用动态列表的方式，声明一个静态属性
比如对某命名空间下的所有类配置到 Hotfix 列表 or 全注入+排除特定 or 放到目录通过正则生成一个类列表等等

public static List<Type> by_property
{get{return (from type int Assembly.Load("Assembly-CSharp").GetTypes()where type.Namespace == "XXX"select type).ToList();}
}

注意：
上线后很难预测那些地方有bug，大部分时候需要把大多数类都囊括在内，然后把一些不需要通过热更新修改bug的部分排除在外（第三方库啥的），然后随着后续的迭代把日趋稳定的模块排除在外。

2.加载Lua文件
有三种方式
a.执行字符串
b.加载lua文件
c.自定义Loader（一般都用这种）

3.连接lua脚本与C#函数：xLua中有两种方式来实现Lua调用CS种德方法，一种是反射调用，一种是生成适配的代码

a.反射调用

[MonoPInvokeCallback(typeof(LuaCSFunction))]
static int FixCSFuction(RealStatePtr L)
{try{ObjectTranslator translator = ObjectTranslatorPool.Instance.Find(L);int idx = LuaAPI.xlua_tointeger(L, LuaAPI.xlua_upvalueindex(1)); //获取闭包中的 upvalue 值LuaCSFunction func = (LuaCSFunction)translator.GetFixCSFunction(idx);  // 获取对应的 LuaCSharpreturn func(L);// 执行}catch (System.Exception e){return LuaAPI.luaL_error(L, "c# exception in FixCSFunction : " + e);}
}

b.生成适配器代码（Generate Code）
在xLua中生成适配代码后会在Gen目录生成代码
根据C#类中需要支持热更的方法，生成对应的委托方法。

注册函数：

// 以偏向减少代码段的方式生成代码
public static void RegisterFunc(RealStatePtr L, int idx, string name, LuaCSFunction func)
{idx = abs_idx(LuaAPI.lua_gettop(L), idx);// idx 就是指CLS_IDX，也就是SetCSTable设置的值LuaAPI.xlua_pushasciistring(L, name);// 压入方法名LuaAPI.lua_pushstdcallcfunction(L, func);// 压入c# wrapperLuaAPI.lua_rawset(L, idx);
}

public static void __Register(RealStatePtr L)
{ObjectTranslator translator = ObjectTranslatorPool.Instance.Find(L);System.Type type = typeof(GameGlobal);//注册成员方法Utils.BeginObjectRegister(type, L, translator, 0, 0, 0, 0);Utils.EndObjectRegister(type, L, translator, null, null,null, null, null);//注册静态方法Utils.BeginClassRegister(type, L, __CreateInstance, 2, 26, 0);//注册回调Utils.RegisterFunc(L, Utils.CLS_IDX, "QuitGame", _m_QuitGame_xlua_st_);Utils.RegisterFunc(L, Utils.CLS_GETTER_IDX, "CoroutineTask", _g_get_CoroutineTask);Utils.RegisterFunc(L, Utils.CLS_GETTER_IDX, "TimeTask", _g_get_TimeTask);Utils.RegisterFunc(L, Utils.CLS_GETTER_IDX, "GameUpdater", _g_get_GameUpdater);Utils.RegisterFunc(L, Utils.CLS_GETTER_IDX, "Color", _g_get_Color);Utils.RegisterFunc(L, Utils.CLS_GETTER_IDX, "GameState", _g_get_GameState);Utils.RegisterFunc(L, Utils.CLS_GETTER_IDX, "GameModule", _g_get_GameModule);Utils.RegisterFunc(L, Utils.CLS_GETTER_IDX, "ResourcesMng", _g_get_ResourcesMng);Utils.RegisterFunc(L, Utils.CLS_GETTER_IDX, "Resources", _g_get_Resources);Utils.RegisterFunc(L, Utils.CLS_GETTER_IDX, "EVDispatcher", _g_get_EVDispatcher);Utils.RegisterFunc(L, Utils.CLS_GETTER_IDX, "UIModule", _g_get_UIModule);Utils.RegisterFunc(L, Utils.CLS_GETTER_IDX, "UIConfig", _g_get_UIConfig);Utils.RegisterFunc(L, Utils.CLS_GETTER_IDX, "UIController", _g_get_UIController);Utils.RegisterFunc(L, Utils.CLS_GETTER_IDX, "RedPoint", _g_get_RedPoint);Utils.RegisterFunc(L, Utils.CLS_GETTER_IDX, "UILayer", _g_get_UILayer);Utils.RegisterFunc(L, Utils.CLS_GETTER_IDX, "Data", _g_get_Data);Utils.RegisterFunc(L, Utils.CLS_GETTER_IDX, "Net", _g_get_Net);Utils.RegisterFunc(L, Utils.CLS_GETTER_IDX, "Version", _g_get_Version);Utils.RegisterFunc(L, Utils.CLS_GETTER_IDX, "SDK", _g_get_SDK);Utils.RegisterFunc(L, Utils.CLS_GETTER_IDX, "HotUpdate", _g_get_HotUpdate);Utils.RegisterFunc(L, Utils.CLS_GETTER_IDX, "DB", _g_get_DB);Utils.RegisterFunc(L, Utils.CLS_GETTER_IDX, "Sound", _g_get_Sound);Utils.RegisterFunc(L, Utils.CLS_GETTER_IDX, "HotFix", _g_get_HotFix);Utils.RegisterFunc(L, Utils.CLS_GETTER_IDX, "HeartPingManager", _g_get_HeartPingManager);Utils.RegisterFunc(L, Utils.CLS_GETTER_IDX, "ApplicateQuit", _g_get_ApplicateQuit);Utils.RegisterFunc(L, Utils.CLS_GETTER_IDX, "ApplicationPaused", _g_get_ApplicationPaused);Utils.RegisterFunc(L, Utils.CLS_GETTER_IDX, "ApplicationFocused", _g_get_ApplicationFocused);Utils.EndClassRegister(type, L, translator);
}...

3.热更脚本注入：在C#脚本编译结束后，使用Mono提供的一套C#的API函数，对已经编译过的.Net体系生成的DLL文件进行修改
xLua对dll注入一些判断条件式来完成
Lua调用的行为很简单，就是检查对应类静态字段是否有 DelegateBridge 对象

（非常长的）源码如下：

        bool injectMethod(MethodDefinition method, HotfixFlagInTool hotfixType){var type = method.DeclaringType;bool isFinalize = (method.Name == "Finalize" && method.IsSpecialName);MethodReference invoke = null;//__Gen_Delegate_Imp 方法引用int param_count = method.Parameters.Count + (method.IsStatic ? 0 : 1);if (!findHotfixDelegate(method, out invoke, hotfixType))// 根据返回值和参数个数类型，查找对应的委托方法{Error("can not find delegate for " + method.DeclaringType + "." + method.Name + "! try re-genertate code.");return false;}if (invoke == null){throw new Exception("unknow exception!");}#if XLUA_GENERALinvoke = injectAssembly.MainModule.ImportReference(invoke);
#elseinvoke = injectAssembly.MainModule.Import(invoke);
#endifFieldReference fieldReference = null;//插入的类静态字段，用来标记是否有对应的Lua注入VariableDefinition injection = null;//方法中的变量顶一bool isIntKey = hotfixType.HasFlag(HotfixFlagInTool.IntKey) && !type.HasGenericParameters && isTheSameAssembly;//isIntKey = !type.HasGenericParameters;if (!isIntKey){injection = new VariableDefinition(invoke.DeclaringType);//新建变量，加入方法体的变量组中method.Body.Variables.Add(injection);//获取这个方法对应的委托名，因为有重载方法存在//所以之前已经注入过的方法会在这边获取时计数+1//比如第一个重载获取的是__Hotfix0，那么下一个重载会是__Hotfix1，判断是否注入就是对应FieldReferencevar luaDelegateName = getDelegateName(method);if (luaDelegateName == null){Error("too many overload!");return false;}//创建对应的静态Field名字 就是上面收取道德luaDelegateNameFieldDefinition fieldDefinition = new FieldDefinition(luaDelegateName, Mono.Cecil.FieldAttributes.Static | Mono.Cecil.FieldAttributes.Private,invoke.DeclaringType);type.Fields.Add(fieldDefinition);fieldReference = fieldDefinition.GetGeneric();}bool ignoreValueType = hotfixType.HasFlag(HotfixFlagInTool.ValueTypeBoxing);//IL插入位置，目前定位的是方法的第一行var insertPoint = method.Body.Instructions[0];//获取IL处理器var processor = method.Body.GetILProcessor();//构造函数的处理逻辑先跳过这边不做分析if (method.IsConstructor){insertPoint = findNextRet(method.Body.Instructions, insertPoint);}Dictionary<Instruction, Instruction> originToNewTarget = new Dictionary<Instruction, Instruction>();HashSet<Instruction> noCheck = new HashSet<Instruction>();while (insertPoint != null){Instruction firstInstruction;if (isIntKey){firstInstruction = processor.Create(OpCodes.Ldc_I4, bridgeIndexByKey.Count);processor.InsertBefore(insertPoint, firstInstruction);processor.InsertBefore(insertPoint, processor.Create(OpCodes.Call, hotfixFlagGetter));}else{//创建第一条 IL 语句，获取类的静态Field压入方法栈用（之前luaDelegateName获取的字段）firstInstruction = processor.Create(OpCodes.Ldsfld, fieldReference);//插入 insertPoint 之前processor.InsertBefore(insertPoint, firstInstruction);//创建并插入IL，获取栈顶的值并压入到对应的变量中（之前创建的新建变量）processor.InsertBefore(insertPoint, processor.Create(OpCodes.Stloc, injection));//创建并插入 IL，压入变量体中的值到栈processor.InsertBefore(insertPoint, processor.Create(OpCodes.Ldloc, injection));}//创建跳转语句，为false时候直接跳转到insertPoint//OpCodes.Brfalse看起来是布尔值判断，其实也会判断是否为nullvar jmpInstruction = processor.Create(OpCodes.Brfalse, insertPoint);processor.InsertBefore(insertPoint, jmpInstruction);if (isIntKey){processor.InsertBefore(insertPoint, processor.Create(OpCodes.Ldc_I4, bridgeIndexByKey.Count));processor.InsertBefore(insertPoint, processor.Create(OpCodes.Call, delegateBridgeGetter));}else{//创建并插入IL，再次压入变量的值，因为上面判断之后，栈顶的值就会被弹出processor.InsertBefore(insertPoint, processor.Create(OpCodes.Ldloc, injection));}//后面就先不分析了。。。for (int i = 0; i < param_count; i++){if (i < ldargs.Length){processor.InsertBefore(insertPoint, processor.Create(ldargs[i]));}else if (i < 256){processor.InsertBefore(insertPoint, processor.Create(OpCodes.Ldarg_S, (byte)i));}else{processor.InsertBefore(insertPoint, processor.Create(OpCodes.Ldarg, (short)i));}if (i == 0 && !method.IsStatic && type.IsValueType){processor.InsertBefore(insertPoint, processor.Create(OpCodes.Ldobj, type));}if (ignoreValueType){TypeReference paramType;if (method.IsStatic){paramType = method.Parameters[i].ParameterType;}else{paramType = (i == 0) ? type : method.Parameters[i - 1].ParameterType;}if (paramType.IsValueType){processor.InsertBefore(insertPoint, processor.Create(OpCodes.Box, paramType));}}}processor.InsertBefore(insertPoint, processor.Create(OpCodes.Call, invoke));if (!method.IsConstructor && !isFinalize){processor.InsertBefore(insertPoint, processor.Create(OpCodes.Ret));}if (!method.IsConstructor){break;}else{originToNewTarget[insertPoint] = firstInstruction;noCheck.Add(jmpInstruction);}insertPoint = findNextRet(method.Body.Instructions, insertPoint);}if (method.IsConstructor){fixBranch(processor, method.Body.Instructions, originToNewTarget, noCheck);}if (isFinalize){if (method.Body.ExceptionHandlers.Count == 0){throw new InvalidProgramException("Finalize has not try-catch? Type :" + method.DeclaringType);}method.Body.ExceptionHandlers[0].TryStart = method.Body.Instructions[0];}if (isIntKey){bridgeIndexByKey.Add(method);}return true;}bool injectGenericMethod(MethodDefinition method, HotfixFlagInTool hotfixType){//如果注入的是xlua所在之外的Assembly的话，不支持该方式if (!isTheSameAssembly){return true;}var type = method.DeclaringType;bool isFinalize = (method.Name == "Finalize" && method.IsSpecialName);bool isIntKey = hotfixType.HasFlag(HotfixFlagInTool.IntKey) && !type.HasGenericParameters;//isIntKey = !type.HasGenericParameters;FieldReference fieldReference = null;VariableDefinition injection = null;if (!isIntKey){var luaDelegateName = getDelegateName(method);if (luaDelegateName == null){Error("too many overload!");return false;}FieldDefinition fieldDefinition = new FieldDefinition(luaDelegateName, Mono.Cecil.FieldAttributes.Static | Mono.Cecil.FieldAttributes.Private,delegateBridgeType);type.Fields.Add(fieldDefinition);fieldReference = fieldDefinition.GetGeneric();}injection = new VariableDefinition(delegateBridgeType);method.Body.Variables.Add(injection);int param_start = method.IsStatic ? 0 : 1;int param_count = method.Parameters.Count + param_start;var insertPoint = method.Body.Instructions[0];var processor = method.Body.GetILProcessor();if (method.IsConstructor){insertPoint = findNextRet(method.Body.Instructions, insertPoint);}Dictionary<Instruction, Instruction> originToNewTarget = new Dictionary<Instruction, Instruction>();HashSet<Instruction> noCheck = new HashSet<Instruction>();while (insertPoint != null){Instruction firstInstruction;Instruction jmpInstruction;if (isIntKey){firstInstruction = processor.Create(OpCodes.Ldc_I4, bridgeIndexByKey.Count);processor.InsertBefore(insertPoint, firstInstruction);processor.InsertBefore(insertPoint, processor.Create(OpCodes.Call, hotfixFlagGetter));jmpInstruction = processor.Create(OpCodes.Brfalse, insertPoint);processor.InsertBefore(insertPoint, jmpInstruction);processor.InsertBefore(insertPoint, processor.Create(OpCodes.Ldc_I4, bridgeIndexByKey.Count));processor.InsertBefore(insertPoint, processor.Create(OpCodes.Call, delegateBridgeGetter));processor.InsertBefore(insertPoint, processor.Create(OpCodes.Stloc, injection));}else{firstInstruction = processor.Create(OpCodes.Ldsfld, fieldReference);processor.InsertBefore(insertPoint, firstInstruction);processor.InsertBefore(insertPoint, processor.Create(OpCodes.Stloc, injection));processor.InsertBefore(insertPoint, processor.Create(OpCodes.Ldloc, injection));jmpInstruction = processor.Create(OpCodes.Brfalse, insertPoint);processor.InsertBefore(insertPoint, jmpInstruction);}processor.InsertBefore(insertPoint, processor.Create(OpCodes.Ldloc, injection));processor.InsertBefore(insertPoint, processor.Create(OpCodes.Callvirt, invokeSessionStart));TypeReference returnType = method.ReturnType;bool isVoid = returnType.FullName == "System.Void";int outCout = 0;for (int i = 0; i < param_count; i++){if (i == 0 && !method.IsStatic){processor.InsertBefore(insertPoint, processor.Create(OpCodes.Ldloc, injection));processor.InsertBefore(insertPoint, processor.Create(OpCodes.Ldarg_0));if (type.IsValueType){processor.InsertBefore(insertPoint, processor.Create(OpCodes.Ldobj, method.DeclaringType.GetGeneric()));}processor.InsertBefore(insertPoint, processor.Create(OpCodes.Callvirt, inParam.MakeGenericMethod(method.DeclaringType.GetGeneric())));}else{var param = method.Parameters[i - param_start];if (param.ParameterType.IsByReference){outCout++;}if (!param.IsOut){processor.InsertBefore(insertPoint, processor.Create(OpCodes.Ldloc, injection));if (i < ldargs.Length){processor.InsertBefore(insertPoint, processor.Create(ldargs[i]));}else if (i < 256){processor.InsertBefore(insertPoint, processor.Create(OpCodes.Ldarg_S, (byte)i));}else{processor.InsertBefore(insertPoint, processor.Create(OpCodes.Ldarg, (short)i));}var paramType = param.ParameterType;if (param.ParameterType.IsByReference){paramType = ((ByReferenceType)paramType).ElementType;if (paramType.IsValueType || paramType.IsGenericParameter){processor.InsertBefore(insertPoint, processor.Create(OpCodes.Ldobj, paramType));}else{processor.InsertBefore(insertPoint, processor.Create(OpCodes.Ldind_Ref));}}if (i == param_count - 1 && param.CustomAttributes.Any(ca => ca.AttributeType.FullName == "System.ParamArrayAttribute")){processor.InsertBefore(insertPoint, processor.Create(OpCodes.Callvirt, inParams.MakeGenericMethod(((ArrayType)paramType).ElementType)));}else{processor.InsertBefore(insertPoint, processor.Create(OpCodes.Callvirt, inParam.MakeGenericMethod(paramType)));}}}}int outStart = (isVoid ? 0 : 1);processor.InsertBefore(insertPoint, processor.Create(OpCodes.Ldloc, injection));processor.InsertBefore(insertPoint, processor.Create(OpCodes.Ldc_I4, outCout + outStart));processor.InsertBefore(insertPoint, processor.Create(OpCodes.Callvirt, functionInvoke));int outPos = outStart;for (int i = 0; i < method.Parameters.Count; i++){if (method.Parameters[i].ParameterType.IsByReference){processor.InsertBefore(insertPoint, processor.Create(OpCodes.Ldloc, injection));processor.InsertBefore(insertPoint, processor.Create(OpCodes.Ldc_I4, outPos));int arg_pos = param_start + i;if (arg_pos < ldargs.Length){processor.InsertBefore(insertPoint, processor.Create(ldargs[arg_pos]));}else if (arg_pos < 256){processor.InsertBefore(insertPoint, processor.Create(OpCodes.Ldarg_S, (byte)arg_pos));}else{processor.InsertBefore(insertPoint, processor.Create(OpCodes.Ldarg, (short)arg_pos));}processor.InsertBefore(insertPoint, processor.Create(OpCodes.Callvirt, outParam.MakeGenericMethod(((ByReferenceType)method.Parameters[i].ParameterType).ElementType)));outPos++;}}processor.InsertBefore(insertPoint, processor.Create(OpCodes.Ldloc, injection));if (isVoid){processor.InsertBefore(insertPoint, processor.Create(OpCodes.Callvirt, invokeSessionEnd));}else{processor.InsertBefore(insertPoint, processor.Create(OpCodes.Callvirt, invokeSessionEndWithResult.MakeGenericMethod(returnType)));}if (!method.IsConstructor && !isFinalize){processor.InsertBefore(insertPoint, processor.Create(OpCodes.Ret));}if (!method.IsConstructor){break;}else{originToNewTarget[insertPoint] = firstInstruction;noCheck.Add(jmpInstruction);}insertPoint = findNextRet(method.Body.Instructions, insertPoint);}if (method.IsConstructor){fixBranch(processor, method.Body.Instructions, originToNewTarget, noCheck);}if (isFinalize){method.Body.ExceptionHandlers[0].TryStart = method.Body.Instructions[0];}if (isIntKey){bridgeIndexByKey.Add(method);}return true;}public void OutputIntKeyMapper(Stream output){using (StreamWriter writer = new StreamWriter(output)){writer.WriteLine("return {");var data = bridgeIndexByKey.Select((md, idx) => new { Method = md, Index = idx}).GroupBy(info => info.Method.DeclaringType).ToDictionary(group => group.Key, group =>{return group.GroupBy(info => info.Method.Name).ToDictionary(group_by_name => group_by_name.Key, group_by_name => group_by_name.Select(info => info.Index.ToString()).ToArray());});foreach(var kv in data){writer.WriteLine("    [\"" + kv.Key.FullName.Replace('/', '+') + "\"] = {");foreach(var kv2 in kv.Value){writer.WriteLine("        [\"" + kv2.Key + "\"] = {");writer.WriteLine("            " + string.Join(",", kv2.Value));writer.WriteLine("        },");}writer.WriteLine("    },");}writer.WriteLine("}");}}

4.执行热更脚本：通过脚本修改C#带有标签的类中的静态变量，把代码的执行路径修改到Lua脚本中
在完成生成代码和注入猴，只要在Lua中调用 xlua.hotfix 或 util.hotfix_ex 方法，就可以实现 c# 代码热更新

-- hotfix 和 hotfix_ex 的区别就是是否可以调用原 c# 代码，其实ex的实现也是调用了hotfix
xlua.hotfix = function(cs, field, func)if func == nil then func = false endlocal tbl = (type(field) == 'table') and field or {[field] = func}
-- 遍历需要 hotfix 的代码，key是方法名，v是对应的funcfor k,v in pairs(tbl) dolocal cflag = ''if k == '.ctor' thenclfag = 'c'k = 'ctor'endlocal f = type(v) == 'fucntion' and v or nil-- 调用 access 方法xlua.acces(cs, cflag..'__Hotfix0_'..k, f) --at least one-- 添加重载方法pcall(function()for i = 1, 99 doxlua.access(cs, cflag..'__Hotfix'..i..'_'..k, f)endend)end-- 设置私有访问xlua.private_accessible(cs)
end

其中额外的东西：
a).xlua.access 对应的c#代码是xLuaAccess代码处理
代码对应 XLua.StaticLuaCallbacks.cs 里面的 XLuaAccess() 方法

[MonoPInvokeCallback(typeof(LuaCSFunction))]
public static int XLuaAccess(RealStatePtr L)
{try{ObjectTranslator translator = ObjectTranslatorPool.Instance.Find(L);Type type = getType(L, translator, 1);object obj = null;if (type == null && LuaAPI.lua_type(L, 1) == LuaTypes.LUA_TUSERDATA){obj = translator.SafeGetCSObj(L, 1);if (obj == null){return LuaAPI.luaL_error(L, "xlua.access, #1 parameter must a type/c# object/string");}type = obj.GetType();}if (type == null){return LuaAPI.luaL_error(L, "xlua.access, can not find c# type");}//将cflag..'__Hotfix0_'..k 转为fieldName，这个字段就是之前Inject时候创建的类的静态字段名string fieldName = LuaAPI.lua_tostring(L, 2);BindingFlags bindingFlags = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static;if (LuaAPI.lua_gettop(L) > 2) // set{//获取函数名称var field = type.GetField(fieldName, bindingFlags);if (field != null){field.SetValue(obj, translator.GetObject(L, 3, field.FieldType));return 0;}var prop = type.GetProperty(fieldName, bindingFlags);if (prop != null){//修改当前函数名称prop.SetValue(obj, translator.GetObject(L, 3, prop.PropertyType), null);return 0;}}else{var field = type.GetField(fieldName, bindingFlags);if (field != null){translator.PushAny(L, field.GetValue(obj));return 1;}var prop = type.GetProperty(fieldName, bindingFlags);if (prop != null){translator.PushAny(L, prop.GetValue(obj, null));return 1;}}return LuaAPI.luaL_error(L, "xlua.access, no field " + fieldName);}catch (Exception e){return LuaAPI.luaL_error(L, "c# exception in xlua.access: " + e);}
}

b).创建修改函数对象
代码对应 XLua.ObjectTranslator.cs 里面的 CreateDelegateBridge () 方法

        public object CreateDelegateBridge(RealStatePtr L, Type delegateType, int idx){LuaAPI.lua_pushvalue(L, idx);LuaAPI.lua_rawget(L, LuaIndexes.LUA_REGISTRYINDEX);if (!LuaAPI.lua_isnil(L, -1)){int referenced = LuaAPI.xlua_tointeger(L, -1);LuaAPI.lua_pop(L, 1);if (delegate_bridges[referenced].IsAlive){if (delegateType == null){return delegate_bridges[referenced].Target;}DelegateBridgeBase exist_bridge = delegate_bridges[referenced].Target as DelegateBridgeBase;Delegate exist_delegate;if (exist_bridge.TryGetDelegate(delegateType, out exist_delegate)){return exist_delegate;}else{exist_delegate = getDelegate(exist_bridge, delegateType);exist_bridge.AddDelegate(delegateType, exist_delegate);return exist_delegate;}}}else{LuaAPI.lua_pop(L, 1);}//push idx对应的值，idx对应的值是Lua中的functionLuaAPI.lua_pushvalue(L, idx);//获取应用的引用idint reference = LuaAPI.luaL_ref(L);//再次压入idx对应的值，idx对应的值是Lua中的函数LuaAPI.lua_pushvalue(L, idx);//压入方法对应的引用idLuaAPI.lua_pushnumber(L, reference);//将栈顶的两个值存入全局变量表中，方便查询是否已经在lua中缓存LuaAPI.lua_rawset(L, LuaIndexes.LUA_REGISTRYINDEX);DelegateBridgeBase bridge;try{
#if (UNITY_EDITOR || XLUA_GENERAL) && !NET_STANDARD_2_0if (!DelegateBridge.Gen_Flag){bridge = Activator.CreateInstance(delegate_birdge_type, new object[] { reference, luaEnv }) as DelegateBridgeBase;}else
#endif{//创建 DeleagteBridge，reference 对应了 lua 中修复的lua函数，在 Inject 时候 call 的方法会使用到这个函数bridge = new DelegateBridge(reference, luaEnv);}}catch(Exception e){LuaAPI.lua_pushvalue(L, idx);LuaAPI.lua_pushnil(L);LuaAPI.lua_rawset(L, LuaIndexes.LUA_REGISTRYINDEX);LuaAPI.lua_pushnil(L);LuaAPI.xlua_rawseti(L, LuaIndexes.LUA_REGISTRYINDEX, reference);throw e;}if (delegateType == null){delegate_bridges[reference] = new WeakReference(bridge);return bridge;}try {var ret = getDelegate(bridge, delegateType);bridge.AddDelegate(delegateType, ret);delegate_bridges[reference] = new WeakReference(bridge);return ret;}catch(Exception e){bridge.Dispose();throw e;}}