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package imap
import (
"fmt"
"math"
"sync"
"time"
"git.sr.ht/~rjarry/aerc/log"
"git.sr.ht/~rjarry/aerc/worker/types"
"github.com/emersion/go-imap"
)
// observer monitors the loggedOut channel of the imap client. If the logout
// signal is received, the observer will emit a connection error to the ui in
// order to start the reconnect cycle.
type observer struct {
sync.Mutex
config imapConfig
client *imapClient
worker *types.Worker
done chan struct{}
autoReconnect bool
retries int
running bool
}
func newObserver(cfg imapConfig, w *types.Worker) *observer {
return &observer{config: cfg, worker: w, done: make(chan struct{})}
}
func (o *observer) SetClient(c *imapClient) {
o.Stop()
o.Lock()
o.client = c
o.Unlock()
o.Start()
o.retries = 0
}
func (o *observer) SetAutoReconnect(auto bool) {
o.autoReconnect = auto
}
func (o *observer) AutoReconnect() bool {
return o.autoReconnect
}
func (o *observer) isClientConnected() bool {
o.Lock()
defer o.Unlock()
return o.client != nil && o.client.State() == imap.SelectedState
}
func (o *observer) EmitIfNotConnected() bool {
if !o.isClientConnected() {
o.emit("imap client not connected: attempt reconnect")
return true
}
return false
}
func (o *observer) IsRunning() bool {
return o.running
}
func (o *observer) Start() {
if o.running {
return
}
if o.client == nil {
return
}
if o.EmitIfNotConnected() {
return
}
go func() {
defer log.PanicHandler()
select {
case <-o.client.LoggedOut():
if o.autoReconnect {
o.emit("logged out")
} else {
o.log("ignore logout (auto-reconnect off)")
}
case <-o.done:
break
}
o.running = false
o.log("stopped")
}()
o.running = true
o.log("started")
}
func (o *observer) Stop() {
if o.client == nil {
return
}
if o.done != nil {
close(o.done)
}
o.done = make(chan struct{})
o.running = false
}
func (o *observer) DelayedReconnect() error {
if o.client == nil {
return nil
}
var wait time.Duration
var reterr error
if o.retries > 0 {
backoff := int(math.Pow(1.8, float64(o.retries)))
var err error
wait, err = time.ParseDuration(fmt.Sprintf("%ds", backoff))
if err != nil {
return err
}
if wait > o.config.reconnect_maxwait {
wait = o.config.reconnect_maxwait
}
reterr = fmt.Errorf("reconnect in %v", wait)
} else {
reterr = fmt.Errorf("reconnect")
}
go func() {
defer log.PanicHandler()
<-time.After(wait)
o.emit(reterr.Error())
}()
o.retries++
return reterr
}
func (o *observer) emit(errMsg string) {
o.worker.PostMessage(&types.Done{
Message: types.RespondTo(&types.Disconnect{}),
}, nil)
o.worker.PostMessage(&types.ConnError{
Error: fmt.Errorf(errMsg),
}, nil)
}
func (o *observer) log(format string, args ...interface{}) {
msg := fmt.Sprintf(format, args...)
o.worker.Tracef("observer (%p) [running:%t] %s", o, o.running, msg)
}
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