syncthing/lib/events/events.go
Jakob Borg 1dbc310c9b cmd/syncthing: Rename event LocalDiskUpdated -> LocalChangeDetected
I think this better reflects what it means. Also tweaks the verbose
format to be more like our other things and lightly refactors the code
to not have the boolean and include the folder in the event.

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/3121
2016-05-19 07:01:43 +00:00

308 lines
6.0 KiB
Go

// Copyright (C) 2014 The Syncthing Authors.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at http://mozilla.org/MPL/2.0/.
// Package events provides event subscription and polling functionality.
package events
import (
"errors"
stdsync "sync"
"time"
"github.com/syncthing/syncthing/lib/sync"
)
type EventType int
const (
Ping EventType = 1 << iota
Starting
StartupComplete
DeviceDiscovered
DeviceConnected
DeviceDisconnected
DeviceRejected
DevicePaused
DeviceResumed
LocalChangeDetected
LocalIndexUpdated
RemoteIndexUpdated
ItemStarted
ItemFinished
StateChanged
FolderRejected
ConfigSaved
DownloadProgress
FolderSummary
FolderCompletion
FolderErrors
FolderScanProgress
ListenAddressesChanged
LoginAttempt
AllEvents = (1 << iota) - 1
)
func (t EventType) String() string {
switch t {
case Ping:
return "Ping"
case Starting:
return "Starting"
case StartupComplete:
return "StartupComplete"
case DeviceDiscovered:
return "DeviceDiscovered"
case DeviceConnected:
return "DeviceConnected"
case DeviceDisconnected:
return "DeviceDisconnected"
case DeviceRejected:
return "DeviceRejected"
case LocalChangeDetected:
return "LocalChangeDetected"
case LocalIndexUpdated:
return "LocalIndexUpdated"
case RemoteIndexUpdated:
return "RemoteIndexUpdated"
case ItemStarted:
return "ItemStarted"
case ItemFinished:
return "ItemFinished"
case StateChanged:
return "StateChanged"
case FolderRejected:
return "FolderRejected"
case ConfigSaved:
return "ConfigSaved"
case DownloadProgress:
return "DownloadProgress"
case FolderSummary:
return "FolderSummary"
case FolderCompletion:
return "FolderCompletion"
case FolderErrors:
return "FolderErrors"
case DevicePaused:
return "DevicePaused"
case DeviceResumed:
return "DeviceResumed"
case FolderScanProgress:
return "FolderScanProgress"
case ListenAddressesChanged:
return "ListenAddressesChanged"
case LoginAttempt:
return "LoginAttempt"
default:
return "Unknown"
}
}
func (t EventType) MarshalText() ([]byte, error) {
return []byte(t.String()), nil
}
const BufferSize = 64
type Logger struct {
subs []*Subscription
nextID int
mutex sync.Mutex
}
type Event struct {
ID int `json:"id"`
Time time.Time `json:"time"`
Type EventType `json:"type"`
Data interface{} `json:"data"`
}
type Subscription struct {
mask EventType
events chan Event
timeout *time.Timer
}
var Default = NewLogger()
var (
ErrTimeout = errors.New("timeout")
ErrClosed = errors.New("closed")
)
func NewLogger() *Logger {
return &Logger{
mutex: sync.NewMutex(),
}
}
func (l *Logger) Log(t EventType, data interface{}) {
l.mutex.Lock()
dl.Debugln("log", l.nextID, t, data)
l.nextID++
e := Event{
ID: l.nextID,
Time: time.Now(),
Type: t,
Data: data,
}
for _, s := range l.subs {
if s.mask&t != 0 {
select {
case s.events <- e:
default:
// if s.events is not ready, drop the event
}
}
}
l.mutex.Unlock()
}
func (l *Logger) Subscribe(mask EventType) *Subscription {
l.mutex.Lock()
dl.Debugln("subscribe", mask)
s := &Subscription{
mask: mask,
events: make(chan Event, BufferSize),
timeout: time.NewTimer(0),
}
// We need to create the timeout timer in the stopped, non-fired state so
// that Subscription.Poll() can safely reset it and select on the timeout
// channel. This ensures the timer is stopped and the channel drained.
if !s.timeout.Stop() {
<-s.timeout.C
}
l.subs = append(l.subs, s)
l.mutex.Unlock()
return s
}
func (l *Logger) Unsubscribe(s *Subscription) {
l.mutex.Lock()
dl.Debugln("unsubscribe")
for i, ss := range l.subs {
if s == ss {
last := len(l.subs) - 1
l.subs[i] = l.subs[last]
l.subs[last] = nil
l.subs = l.subs[:last]
break
}
}
close(s.events)
l.mutex.Unlock()
}
// Poll returns an event from the subscription or an error if the poll times
// out of the event channel is closed. Poll should not be called concurrently
// from multiple goroutines for a single subscription.
func (s *Subscription) Poll(timeout time.Duration) (Event, error) {
dl.Debugln("poll", timeout)
s.timeout.Reset(timeout)
select {
case e, ok := <-s.events:
if !ok {
return e, ErrClosed
}
if !s.timeout.Stop() {
// The timeout must be stopped and possibly drained to be ready
// for reuse in the next call.
<-s.timeout.C
}
return e, nil
case <-s.timeout.C:
return Event{}, ErrTimeout
}
}
func (s *Subscription) C() <-chan Event {
return s.events
}
type bufferedSubscription struct {
sub *Subscription
buf []Event
next int
cur int
mut sync.Mutex
cond *stdsync.Cond
}
type BufferedSubscription interface {
Since(id int, into []Event) []Event
}
func NewBufferedSubscription(s *Subscription, size int) BufferedSubscription {
bs := &bufferedSubscription{
sub: s,
buf: make([]Event, size),
mut: sync.NewMutex(),
}
bs.cond = stdsync.NewCond(bs.mut)
go bs.pollingLoop()
return bs
}
func (s *bufferedSubscription) pollingLoop() {
for {
ev, err := s.sub.Poll(60 * time.Second)
if err == ErrTimeout {
continue
}
if err == ErrClosed {
return
}
if err != nil {
panic("unexpected error: " + err.Error())
}
s.mut.Lock()
s.buf[s.next] = ev
s.next = (s.next + 1) % len(s.buf)
s.cur = ev.ID
s.cond.Broadcast()
s.mut.Unlock()
}
}
func (s *bufferedSubscription) Since(id int, into []Event) []Event {
s.mut.Lock()
defer s.mut.Unlock()
for id >= s.cur {
s.cond.Wait()
}
for i := s.next; i < len(s.buf); i++ {
if s.buf[i].ID > id {
into = append(into, s.buf[i])
}
}
for i := 0; i < s.next; i++ {
if s.buf[i].ID > id {
into = append(into, s.buf[i])
}
}
return into
}
// Error returns a string pointer suitable for JSON marshalling errors. It
// retains the "null on success" semantics, but ensures the error result is a
// string regardless of the underlying concrete error type.
func Error(err error) *string {
if err == nil {
return nil
}
str := err.Error()
return &str
}