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Matteo Scandoloa6a3aee2019-11-26 13:30:14 -07001// Copyright (c) 2013 - Max Persson <max@looplab.se>
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7// http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15package fsm
16
17// Event is the info that get passed as a reference in the callbacks.
18type Event struct {
19 // FSM is a reference to the current FSM.
20 FSM *FSM
21
22 // Event is the event name.
23 Event string
24
25 // Src is the state before the transition.
26 Src string
27
28 // Dst is the state after the transition.
29 Dst string
30
31 // Err is an optional error that can be returned from a callback.
32 Err error
33
34 // Args is a optinal list of arguments passed to the callback.
35 Args []interface{}
36
37 // canceled is an internal flag set if the transition is canceled.
38 canceled bool
39
40 // async is an internal flag set if the transition should be asynchronous
41 async bool
42}
43
44// Cancel can be called in before_<EVENT> or leave_<STATE> to cancel the
45// current transition before it happens. It takes an opitonal error, which will
46// overwrite e.Err if set before.
47func (e *Event) Cancel(err ...error) {
48 e.canceled = true
49
50 if len(err) > 0 {
51 e.Err = err[0]
52 }
53}
54
55// Async can be called in leave_<STATE> to do an asynchronous state transition.
56//
57// The current state transition will be on hold in the old state until a final
58// call to Transition is made. This will comlete the transition and possibly
59// call the other callbacks.
60func (e *Event) Async() {
61 e.async = true
62}