xpipline.go

package typex

import (
	"errors"
	"strconv"

	lua "github.com/hootrhino/gopher-lua"
)

// RunPipline
//
//	Run lua as pipline
func RunPipline(vm *lua.LState, funcs map[string]*lua.LFunction, arg lua.LValue) (lua.LValue, error) {
	// start 1
	acc := 1
	return pipLine(vm, acc, funcs, arg)
}

func pipLine(vm *lua.LState, acc int, funcs map[string]*lua.LFunction, arg lua.LValue) (lua.LValue, error) {
	if acc == len(funcs) {
		values, err0 := callLuaFunc(vm, funcs[strconv.Itoa(acc)], arg)
		if err0 != nil {
			return nil, err0
		}
		return validate(values, func() (lua.LValue, error) {
			result := values[1]
			return result, nil
		})

	}
	values, err0 := callLuaFunc(vm, funcs[strconv.Itoa(acc)], arg)
	if err0 != nil {
		return nil, err0
	}
	return validate(values, func() (lua.LValue, error) {
		next := values[0]
		result := values[1]
		if next.Type() == lua.LTBool {
			if next.(lua.LBool) {
				return pipLine(vm, acc+1, funcs, result)
			}
			return result, nil
		}
		return nil, errors.New("'Action' callback first argument is must be bool")

	})

}

// validate lua callback
func validate(values []lua.LValue, f func() (lua.LValue, error)) (lua.LValue, error) {
	// Lua call back must have 2 args!!!
	if len(values) != 2 {
		return nil, errors.New("'Action' callback must have 2 return value:[bool, T]")
	} else {
		return f()
	}
}

// 执行lua函数的接口, 后期可以用这个接口来实现运行 lua 微服务
func Execute(vm *lua.LState, k string, args ...lua.LValue) (interface{}, error) {
	callable := vm.GetGlobal(k)
	if callable.Type() == lua.LTFunction {
		return callLuaFunc(vm, callable.(*lua.LFunction), args...)
	}
	return nil, errors.New("target:" + k + " is not a lua function")
}

// callLuaFunc
func callLuaFunc(vm *lua.LState, callable *lua.LFunction, args ...lua.LValue) ([]lua.LValue, error) {
	if callable == nil {
		return nil, errors.New("callable function is not exists")
	}
	err := vm.CallByParam(lua.P{
		Fn:      callable,
		NRet:    2,
		Protect: true,
	}, args...)
	if err != nil {
		return nil, err
	}
	vm.Pop(-1)
	vm.Pop(-2)
	vm.Pop(-3)
	return []lua.LValue{vm.Get(-2), vm.Get(-1)}, nil

}