Golang C.lua_getfield函數代碼示例

// Executes an aggregation over the iterator.
func (e *ExecutionEngine) Aggregate() (interface{}, error) {
	functionName := C.CString("sky_aggregate")
	defer C.free(unsafe.Pointer(functionName))

	C.lua_getfield(e.state, -10002, functionName)
	C.lua_pushlightuserdata(e.state, unsafe.Pointer(e.cursor))
	rc := C.lua_pcall(e.state, 1, 1, 0)
	if rc != 0 {
		luaErrString := C.GoString(C.lua_tolstring(e.state, -1, nil))
		fmt.Println(e.FullAnnotatedSource())
		return nil, fmt.Errorf("skyd.ExecutionEngine: Unable to aggregate: %s", luaErrString)
	}

	return e.decodeResult()
}

// Pcall calls a lua function. no panic
func (l *Lua) Pcall(fullname string, args ...interface{}) (returns []interface{}, err error) {
	C.push_errfunc(l.State)
	curTop := C.lua_gettop(l.State)
	// get function
	path := strings.Split(fullname, ".")
	for i, name := range path {
		if i == 0 {
			C.lua_getfield(l.State, C.LUA_GLOBALSINDEX, cstr(name))
		} else {
			if C.lua_type(l.State, -1) != C.LUA_TTABLE {
				return nil, fmt.Errorf("%s is not a function", fullname)
			}
			C.lua_pushstring(l.State, cstr(name))
			C.lua_gettable(l.State, -2)
			C.lua_remove(l.State, -2) // remove table
		}
	}
	if C.lua_type(l.State, -1) != C.LUA_TFUNCTION {
		return nil, fmt.Errorf("%s is not a function", fullname)
	}
	// args
	for _, arg := range args {
		l.pushGoValue(arg, "")
	}
	// call
	l.err = nil
	if ret := C.lua_pcall(l.State, C.int(len(args)), C.LUA_MULTRET, C.int(-(len(args))-2)); ret != 0 {
		// error occured
		return nil, fmt.Errorf("CALL ERROR: %s", C.GoString(C.lua_tolstring(l.State, -1, nil)))
	} else if l.err != nil { // error raise by invokeGoFunc
		return nil, l.err
	} else {
		// return values
		nReturn := C.lua_gettop(l.State) - curTop
		returns = make([]interface{}, int(nReturn))
		for i := C.int(0); i < nReturn; i++ {
			value, err := l.toGoValue(-1-i, interfaceType)
			if err != nil {
				return nil, err
			}
			returns[int(nReturn-1-i)] = value.Interface()
		}
	}
	return
}

// Executes an merge over the iterator.
func (e *ExecutionEngine) Merge(results interface{}, data interface{}) (interface{}, error) {
	functionName := C.CString("sky_merge")
	defer C.free(unsafe.Pointer(functionName))

	C.lua_getfield(e.state, -10002, functionName)
	err := e.encodeArgument(results)
	if err != nil {
		return results, err
	}
	err = e.encodeArgument(data)
	if err != nil {
		return results, err
	}
	rc := C.lua_pcall(e.state, 2, 1, 0)
	if rc != 0 {
		luaErrString := C.GoString(C.lua_tolstring(e.state, -1, nil))
		fmt.Println(e.FullAnnotatedSource())
		return results, fmt.Errorf("skyd.ExecutionEngine: Unable to merge: %s", luaErrString)
	}

	return e.decodeResult()
}

// Initializes the cursor used by the script.
func (e *ExecutionEngine) initCursor() error {
	// Create the cursor.
	minPropertyId, maxPropertyId := e.propertyFile.NextIdentifiers()
	e.cursor = C.sky_cursor_new((C.int32_t)(minPropertyId), (C.int32_t)(maxPropertyId))
	e.cursor.context = unsafe.Pointer(e)
	C.executionEngine_setNextObjectFunc(unsafe.Pointer(e.cursor))

	// Initialize the cursor from within Lua.
	functionName := C.CString("sky_init_cursor")
	defer C.free(unsafe.Pointer(functionName))

	C.lua_getfield(e.state, -10002, functionName)
	C.lua_pushlightuserdata(e.state, unsafe.Pointer(e.cursor))
	//fmt.Printf("%s\n\n", e.FullAnnotatedSource())
	rc := C.lua_pcall(e.state, 1, 0, 0)
	if rc != 0 {
		luaErrString := C.GoString(C.lua_tolstring(e.state, -1, nil))
		return fmt.Errorf("Unable to init cursor: %s", luaErrString)
	}

	return nil
}

// luaL_getmetatable
func (L *State) LGetMetaTable(tname string) {
	Ctname := C.CString(tname)
	defer C.free(unsafe.Pointer(Ctname))
	C.lua_getfield(L.s, LUA_REGISTRYINDEX, Ctname)
}

// lua_getfield
func (L *State) GetField(index int, k string) {
	Ck := C.CString(k)
	defer C.free(unsafe.Pointer(Ck))
	C.lua_getfield(L.s, C.int(index), Ck)
}

// Pushes onto the stack the value t[k], where t is the value at the
// given valid index.
func (this *State) Getfield(index int, k string) {
	cs := C.CString(k)
	defer C.free(unsafe.Pointer(cs))
	C.lua_getfield(this.luastate, C.int(index), cs)
}

func (L *State) GetField(index int, k string) {
	C.lua_getfield(L.s, C.int(index), C.CString(k))
}

func (l *Lua) getStackTraceback() string {
	C.lua_getfield(l.State, C.LUA_GLOBALSINDEX, cstr("debug"))
	C.lua_getfield(l.State, -1, cstr("traceback"))
	C.lua_call(l.State, 0, 1)
	return C.GoString(C.lua_tolstring(l.State, -1, nil))
}

//TODO: rename better... clashes with lua_getmetatable
func LGetMetaTable(L *State, tname string) {
	//C.luaL_getmetatable(L.s,C.CString(tname));
	C.lua_getfield(L.s, LUA_REGISTRYINDEX, C.CString(tname))
}