/// <summary>
/// 根据上下文，生成一个Action
/// </summary>
/// <param name="cmdContext"></param>
/// <returns></returns>
IAction Generate(ActionGenerationContext cmdContext)
{
//获取所有参数
var parameters = cmdContext.ActionMethodInfo.GetParameters();
//函数调用的参数列表
var argExprs = new List<ParameterExpression>();
//循环所有参数
foreach (var par in parameters)
{
#region 生成为每个参数赋值的表达式
//构建参数上下文
var parContext = new ActionGenerationParameterBindContext(cmdContext,par);
//把参数变量添加到变量表中
cmdContext.LocalVarExpressions.Add(parContext.LocalExpression);
argExprs.Add(parContext.LocalExpression);
//生成绑定参数值的表达式
if (parContext.NullableChecker.IsNullable)
{
GenerateNullableBindCodes(parContext);
}
else {
GenerateNonullableBindCodes(parContext);
}
#endregion
}
#region 生成函数调用 controllerInstance.Insert(username,password);
var instanceExpr = cmdContext.ControllerInstanceExpression;
var instanceConvertExpr = Expression.Convert(instanceExpr,cmdContext.ActionMethodInfo.DeclaringType);
var callExpr = Expression.Call(instanceConvertExpr, cmdContext.ActionMethodInfo, argExprs);
cmdContext.CodeExpressions.Add(callExpr);
#endregion
//根据Action Method的不同返回值类型，生成不同的Action
return GenerateReturn(cmdContext,callExpr);
}
void GenerateValueTypeBindCodes(ActionGenerationParameterBindContext parContext, Func<string, object> parser)
{
//定义一个临时变量
var tmpVarExp = Expression.Parameter(typeof(object), "___EXTEmPORanEous_" + parContext.ParameterInfo.Name);
parContext.LocalVarExpressions.Add(tmpVarExp);
//获取parse的值到临时变量中
var getValueExpr = Expression.Invoke(Expression.Constant(parser), parContext.GetItemExpression);
var tmpAssignExpr = Expression.Assign(tmpVarExp, getValueExpr);
parContext.CodeExpressions.Add(tmpAssignExpr);
//if(tmp_username==null) username = "******";else username = (string)temp_usernmae;
var initExpr = GenerateInitCodes(parContext);
var convertExpr = Expression.Convert(getValueExpr, parContext.ParameterType);
var code = Expression.IfThenElse(Expression.Equal(tmpVarExp, Expression.Constant(null, typeof(object)))
, initExpr
, Expression.Assign(parContext.LocalExpression, convertExpr)
);
parContext.CodeExpressions.Add(code);
}
void GenerateStringBindCodes(ActionGenerationParameterBindContext parContext)
{
//申请一个临时变量
//string ___EXTEmPORanEous_username;
var tmpVarExp = Expression.Parameter(typeof(string), "___EXTEmPORanEous_" + parContext.ParameterInfo.Name);
parContext.LocalVarExpressions.Add(tmpVarExp);
//从arguments中拿到值
//___EXTEmPORanEous_username = arguments["username"];
var assignExpr = Expression.Assign(tmpVarExp, parContext.GetItemExpression);
parContext.CodeExpressions.Add(assignExpr);
//如果是null，就赋默认值，否者就赋临时变量的值
//username = ___EXTEmPORanEous_username==null?string.Empty:___EXTEmPORanEous_username
var condExpr = Expression.IfThenElse(
Expression.Equal(tmpVarExp, Expression.Constant(null, typeof(string)))
, GenerateInitCodes(parContext)
, Expression.Assign(parContext.LocalExpression, tmpVarExp)
);
parContext.CodeExpressions.Add(condExpr);
}
/// <summary>
/// 给Nullable<>的参数变量赋值
/// </summary>
/// <param name="parContext"></param>
void GenerateNullableBindCodes(ActionGenerationParameterBindContext parContext)
{
Expression assignExpr = null;
if (parContext.NullableChecker.ActualType.IsEnum)
{
var method = ParseNullableEnumMethodInfo.MakeGenericMethod(parContext.NullableChecker.ActualType);
// ParseEnum<T>(_ARGUMENTS['par_name']);
var parseExpr = Expression.Call(null, method, parContext.GetItemExpression);
assignExpr = Expression.Assign(parContext.LocalExpression, parseExpr);
}
else
{
var binder = NullableTypes.GetParser(parContext.NullableChecker);
if (binder == null) throw new Exception(parContext.NullableChecker.ActualType.FullName + " is not supported to bind as nullable<>");
var getValueExpr = Expression.Invoke(Expression.Constant(binder), parContext.GetItemExpression);
var convertExpr = Expression.Convert(getValueExpr, parContext.ParameterType);
// local = (T?)NullableTypes.GetParser(typeof(T))(_ARGUMENTS["parameter_name"]);
assignExpr = Expression.Assign(parContext.LocalExpression, convertExpr);
}
parContext.CodeExpressions.Add(assignExpr);
var hasValueExpr = Expression.Call(parContext.LocalExpression,
parContext.ParameterType.GetMethod("get_HasValue")
);
var ckExpr = Expression.IfThen(Expression.Not(hasValueExpr)
, GenerateInitCodes(parContext)
);
parContext.CodeExpressions.Add(ckExpr);
}
/// <summary>
/// 给不是 Nullable<>的参数变量赋值
/// </summary>
/// <param name="parContext"></param>
void GenerateNonullableBindCodes(ActionGenerationParameterBindContext parContext)
{
Func<ParameterInfo, IArguments, IRequest, Context, object> binder =
parContext.BinderFactory == null ?null: parContext.BinderFactory(parContext.ParameterInfo,parContext.CommandText,parContext.HttpMethod);
if (binder == null)
{
GenerateDefaultNonullableBindCodes(parContext);
}
else {
var tmpVarExp = Expression.Parameter(typeof(object), "___EXTEmPORanEous_" + parContext.ParameterInfo.Name);
parContext.LocalVarExpressions.Add(tmpVarExp);
var getValueExpr = Expression.Invoke(Expression.Constant(binder), Expression.Constant(parContext.ParameterInfo),parContext.ArgumentsExpression,parContext.RequestExpression,parContext.ContextExpression);
var tmpAssignExpr = Expression.Assign(tmpVarExp, getValueExpr);
var initExpr = GenerateInitCodes(parContext);
var convertExpr = Expression.Convert(getValueExpr, parContext.ParameterType);
var code = Expression.IfThenElse(Expression.Equal(tmpVarExp, Expression.Constant(null, typeof(object)))
, initExpr
, Expression.Assign(parContext.LocalExpression, convertExpr)
);
parContext.CodeExpressions.Add(code);
}
}
/// <summary>
/// 生成初始化代码 gender = Genders.Secret;
/// </summary>
/// <param name="parContext"></param>
/// <returns></returns>
Expression GenerateInitCodes(ActionGenerationParameterBindContext parContext)
{
Expression initParExpr = null;
if (parContext.ParameterInfo.HasDefaultValue)
{
initParExpr = Expression.Assign(parContext.LocalExpression, Expression.Constant(parContext.ParameterInfo.DefaultValue, parContext.ParameterType));
}
else
{
var defaultValue = ValueTypes.GetDefaultValue(parContext.ParameterType);
var defaultValueExpr = Expression.Convert(Expression.Constant(defaultValue, typeof(object)), parContext.ParameterType);
initParExpr = Expression.Assign(parContext.LocalExpression, defaultValueExpr);
}
return initParExpr;
}
void GenerateDefaultNonullableBindCodes(ActionGenerationParameterBindContext parContext)
{
if (parContext.ParameterType == typeof(string)) {
this.GenerateStringBindCodes(parContext);
return;
}
var vparser = ValueTypes.GetParser(parContext.ParameterType);
if (vparser == null)
{
var initExpr = GenerateInitCodes(parContext);
parContext.CodeExpressions.Add(initExpr);
//binder = this.ParameterBinderFactory.GetBinder(par, cmdText,)
}
else
{
GenerateValueTypeBindCodes(parContext, vparser);
}
}