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// -*- Mode: Go; indent-tabs-mode: t -*-
/*
* Copyright (C) 2020 Canonical Ltd
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
package triggerwatch
import (
"errors"
"fmt"
"time"
"github.com/snapcore/snapd/logger"
)
type triggerProvider interface {
FindMatchingDevices(filter triggerEventFilter) ([]triggerDevice, error)
}
type triggerDevice interface {
WaitForTrigger(chan keyEvent)
String() string
Close()
}
var (
// trigger mechanism
trigger triggerProvider
// wait for '1' to be pressed
triggerFilter = triggerEventFilter{Key: "KEY_1"}
ErrTriggerNotDetected = errors.New("trigger not detected")
ErrNoMatchingInputDevices = errors.New("no matching input devices")
)
// Wait waits for a trigger on the available trigger devices for a given amount
// of time. Returns nil if one was detected, ErrTriggerNotDetected if timeout
// was hit, or other non-nil error.
func Wait(timeout time.Duration) error {
if trigger == nil {
logger.Panicf("trigger is unset")
}
devices, err := trigger.FindMatchingDevices(triggerFilter)
if err != nil {
return fmt.Errorf("cannot list trigger devices: %v", err)
}
if devices == nil {
return ErrNoMatchingInputDevices
}
logger.Noticef("waiting for trigger key: %v", triggerFilter.Key)
detectKeyCh := make(chan keyEvent, len(devices))
for _, dev := range devices {
go dev.WaitForTrigger(detectKeyCh)
defer dev.Close()
}
select {
case kev := <-detectKeyCh:
if kev.Err != nil {
return err
}
// channel got closed without an error
logger.Noticef("%s: + got trigger key %v", kev.Dev, triggerFilter.Key)
case <-time.After(timeout):
return ErrTriggerNotDetected
}
return nil
}
|
