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|
package types
import (
"container/list"
"sync"
"sync/atomic"
"git.sr.ht/~rjarry/aerc/lib/log"
"git.sr.ht/~rjarry/aerc/models"
)
type WorkerInteractor interface {
log.Logger
Actions() chan WorkerMessage
ProcessAction(WorkerMessage) WorkerMessage
PostAction(WorkerMessage, func(msg WorkerMessage))
PostMessage(WorkerMessage, func(msg WorkerMessage))
Unwrap() WorkerInteractor
Name() string
}
var lastId int64 = 1 // access via atomic
type Backend interface {
Run()
Capabilities() *models.Capabilities
PathSeparator() string
}
type Worker struct {
Backend Backend
actions chan WorkerMessage
actionCallbacks map[int64]func(msg WorkerMessage)
messageCallbacks map[int64]func(msg WorkerMessage)
actionQueue *list.List
status int32
name string
sync.Mutex
log.Logger
}
func NewWorker(name string) *Worker {
return &Worker{
Logger: log.NewLogger(name, 2),
actions: make(chan WorkerMessage),
actionCallbacks: make(map[int64]func(msg WorkerMessage)),
messageCallbacks: make(map[int64]func(msg WorkerMessage)),
actionQueue: list.New(),
name: name,
}
}
func (worker *Worker) Unwrap() WorkerInteractor {
return nil
}
func (worker *Worker) Actions() chan WorkerMessage {
return worker.actions
}
func (worker *Worker) Name() string {
return worker.name
}
func (worker *Worker) setId(msg WorkerMessage) {
id := atomic.AddInt64(&lastId, 1)
msg.setId(id)
}
const (
idle int32 = iota
busy
)
// Add a new task to the action queue without blocking. Start processing the
// queue in the background if needed.
func (worker *Worker) queue(msg WorkerMessage) {
worker.Lock()
defer worker.Unlock()
worker.actionQueue.PushBack(msg)
if atomic.LoadInt32(&worker.status) == idle {
atomic.StoreInt32(&worker.status, busy)
go worker.processQueue()
}
}
// Start processing the action queue and write all messages to the actions
// channel, one by one. Stop when the action queue is empty.
func (worker *Worker) processQueue() {
defer log.PanicHandler()
for {
worker.Lock()
e := worker.actionQueue.Front()
if e == nil {
atomic.StoreInt32(&worker.status, idle)
worker.Unlock()
return
}
msg := worker.actionQueue.Remove(e).(WorkerMessage)
worker.Unlock()
worker.actions <- msg
}
}
// PostAction posts an action to the worker. This method should not be called
// from the same goroutine that the worker runs in or deadlocks may occur
func (worker *Worker) PostAction(msg WorkerMessage, cb func(msg WorkerMessage)) {
worker.setId(msg)
// write to actions channel without blocking
worker.queue(msg)
if cb != nil {
worker.Lock()
worker.actionCallbacks[msg.getId()] = cb
worker.Unlock()
}
}
var WorkerMessages = make(chan WorkerMessage, 50)
// PostMessage posts an message to the UI. This method should not be called
// from the same goroutine that the UI runs in or deadlocks may occur
func (worker *Worker) PostMessage(msg WorkerMessage,
cb func(msg WorkerMessage),
) {
worker.setId(msg)
msg.setAccount(worker.name)
WorkerMessages <- msg
if cb != nil {
worker.Lock()
worker.messageCallbacks[msg.getId()] = cb
worker.Unlock()
}
}
func (worker *Worker) ProcessMessage(msg WorkerMessage) WorkerMessage {
if inResponseTo := msg.InResponseTo(); inResponseTo != nil {
worker.Lock()
f, ok := worker.actionCallbacks[inResponseTo.getId()]
worker.Unlock()
if ok {
f(msg)
switch msg.(type) {
case *Cancelled, *Done:
worker.Lock()
delete(worker.actionCallbacks, inResponseTo.getId())
worker.Unlock()
}
}
}
return msg
}
func (worker *Worker) ProcessAction(msg WorkerMessage) WorkerMessage {
if inResponseTo := msg.InResponseTo(); inResponseTo != nil {
worker.Lock()
f, ok := worker.messageCallbacks[inResponseTo.getId()]
worker.Unlock()
if ok {
f(msg)
if _, ok := msg.(*Done); ok {
worker.Lock()
delete(worker.messageCallbacks, inResponseTo.getId())
worker.Unlock()
}
}
}
return msg
}
func (worker *Worker) PathSeparator() string {
return worker.Backend.PathSeparator()
}
|
