98bc96c911
This also increases the max allowed to 5% -- I'm happy to make this lower if someone asks.
120 lines
3.1 KiB
Go
120 lines
3.1 KiB
Go
// Mgmt
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// Copyright (C) 2013-2017+ James Shubin and the project contributors
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// Written by James Shubin <james@shubin.ca> and the project contributors
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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// Package event provides some primitives that are used for message passing.
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package event
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import (
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"fmt"
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)
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//go:generate stringer -type=Kind -output=kind_stringer.go
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// Kind represents the type of event being passed.
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type Kind int
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// The different event kinds are used in different contexts.
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const (
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EventNil Kind = iota
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EventExit
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EventStart
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EventPause
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EventPoke
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EventBackPoke
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)
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// Resp is a channel to be used for boolean responses. A nil represents an ACK,
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// and a non-nil represents a NACK (false). This also lets us use custom errors.
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type Resp chan error
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// Event is the main struct that stores event information and responses.
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type Event struct {
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Kind Kind
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Resp Resp // channel to send an ack response on, nil to skip
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//Wg *sync.WaitGroup // receiver barrier to Wait() for everyone else on
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Err error // store an error in our event
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}
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// ACK sends a single acknowledgement on the channel if one was requested.
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func (event *Event) ACK() {
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if event.Resp != nil { // if they've requested an ACK
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event.Resp.ACK()
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}
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}
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// NACK sends a negative acknowledgement message on the channel if one was requested.
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func (event *Event) NACK() {
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if event.Resp != nil { // if they've requested a NACK
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event.Resp.NACK()
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}
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}
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// ACKNACK sends a custom ACK or NACK message on the channel if one was requested.
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func (event *Event) ACKNACK(err error) {
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if event.Resp != nil { // if they've requested a NACK
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event.Resp.ACKNACK(err)
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}
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}
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// NewResp is just a helper to return the right type of response channel.
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func NewResp() Resp {
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resp := make(chan error)
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return resp
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}
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// ACK sends a true value to resp.
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func (resp Resp) ACK() {
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if resp != nil {
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resp <- nil // TODO: close instead?
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}
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}
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// NACK sends a false value to resp.
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func (resp Resp) NACK() {
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if resp != nil {
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resp <- fmt.Errorf("NACK")
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}
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}
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// ACKNACK sends a custom ACK or NACK. The ACK value is always nil, the NACK can
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// be any non-nil error value.
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func (resp Resp) ACKNACK(err error) {
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if resp != nil {
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resp <- err
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}
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}
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// Wait waits for any response from a Resp channel and returns it.
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func (resp Resp) Wait() error {
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return <-resp
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}
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// ACKWait waits for a +ive Ack from a Resp channel.
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func (resp Resp) ACKWait() {
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for {
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// wait until true value
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if resp.Wait() == nil {
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return
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}
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}
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}
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// Error returns the stored error value.
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func (event *Event) Error() error {
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return event.Err
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}
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