9ef2a57b51
Worker.Process* functions were called in different goroutines than Worker.Post*. Protect the map with a mutex. Also make the map unexported to prevent external unprotected accesses. Worker.Process* functions used to delete items from the map. However they didn't delete the element they retrieved: callbacks[msg.InResponseTo()] was read while callbacks[msg] was deleted. I'm not sure I understand why. I tried to delete the element that was accessed - but this broke everything (UI froze at "Connecting..."). I don't believe any elements were actually removed from the map, so the new code just doesn't remove anything.
100 lines
2.1 KiB
Go
100 lines
2.1 KiB
Go
package types
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import (
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"log"
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"sync"
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)
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type Backend interface {
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Run()
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}
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type Worker struct {
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Backend Backend
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Actions chan WorkerMessage
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Messages chan WorkerMessage
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Logger *log.Logger
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callbacks map[WorkerMessage]func(msg WorkerMessage) // protected by mutex
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mutex sync.Mutex
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}
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func NewWorker(logger *log.Logger) *Worker {
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return &Worker{
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Actions: make(chan WorkerMessage, 50),
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Messages: make(chan WorkerMessage, 50),
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Logger: logger,
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callbacks: make(map[WorkerMessage]func(msg WorkerMessage)),
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}
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}
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func (worker *Worker) setCallback(msg WorkerMessage,
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cb func(msg WorkerMessage)) {
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if cb != nil {
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worker.mutex.Lock()
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worker.callbacks[msg] = cb
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worker.mutex.Unlock()
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}
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}
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func (worker *Worker) getCallback(msg WorkerMessage) (func(msg WorkerMessage),
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bool) {
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worker.mutex.Lock()
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cb, ok := worker.callbacks[msg]
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worker.mutex.Unlock()
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return cb, ok
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}
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func (worker *Worker) PostAction(msg WorkerMessage,
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cb func(msg WorkerMessage)) {
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if resp := msg.InResponseTo(); resp != nil {
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worker.Logger.Printf("(ui)=> %T:%T\n", msg, resp)
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} else {
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worker.Logger.Printf("(ui)=> %T\n", msg)
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}
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worker.Actions <- msg
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worker.setCallback(msg, cb)
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}
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func (worker *Worker) PostMessage(msg WorkerMessage,
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cb func(msg WorkerMessage)) {
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if resp := msg.InResponseTo(); resp != nil {
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worker.Logger.Printf("->(ui) %T:%T\n", msg, resp)
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} else {
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worker.Logger.Printf("->(ui) %T\n", msg)
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}
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worker.Messages <- msg
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worker.setCallback(msg, cb)
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}
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func (worker *Worker) ProcessMessage(msg WorkerMessage) WorkerMessage {
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if resp := msg.InResponseTo(); resp != nil {
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worker.Logger.Printf("(ui)<= %T:%T\n", msg, resp)
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} else {
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worker.Logger.Printf("(ui)<= %T\n", msg)
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}
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if cb, ok := worker.getCallback(msg.InResponseTo()); ok {
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cb(msg)
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}
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return msg
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}
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func (worker *Worker) ProcessAction(msg WorkerMessage) WorkerMessage {
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if resp := msg.InResponseTo(); resp != nil {
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worker.Logger.Printf("<-(ui) %T:%T\n", msg, resp)
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} else {
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worker.Logger.Printf("<-(ui) %T\n", msg)
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}
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if cb, ok := worker.getCallback(msg.InResponseTo()); ok {
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cb(msg)
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}
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return msg
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}
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