104 lines
2.4 KiB
Go
104 lines
2.4 KiB
Go
// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
|
|
// Use of this source code is governed by the MIT license that can be
|
|
// found in the LICENSE file.
|
|
|
|
package notify
|
|
|
|
// EventDiff describes a change to an event set - EventDiff[0] is an old state,
|
|
// while EventDiff[1] is a new state. If event set has not changed (old == new),
|
|
// functions typically return the None value.
|
|
type eventDiff [2]Event
|
|
|
|
func (diff eventDiff) Event() Event {
|
|
return diff[1] &^ diff[0]
|
|
}
|
|
|
|
// Watchpoint
|
|
//
|
|
// The nil key holds total event set - logical sum for all registered events.
|
|
// It speeds up computing EventDiff for Add method.
|
|
//
|
|
// The rec key holds an event set for a watchpoints created by RecursiveWatch
|
|
// for a Watcher implementation which is not natively recursive.
|
|
type watchpoint map[chan<- EventInfo]Event
|
|
|
|
// None is an empty event diff, think null object.
|
|
var none eventDiff
|
|
|
|
// rec is just a placeholder
|
|
var rec = func() (ch chan<- EventInfo) {
|
|
ch = make(chan<- EventInfo)
|
|
close(ch)
|
|
return
|
|
}()
|
|
|
|
func (wp watchpoint) dryAdd(ch chan<- EventInfo, e Event) eventDiff {
|
|
if e &^= internal; wp[ch]&e == e {
|
|
return none
|
|
}
|
|
total := wp[ch] &^ internal
|
|
return eventDiff{total, total | e}
|
|
}
|
|
|
|
// Add assumes neither c nor e are nil or zero values.
|
|
func (wp watchpoint) Add(c chan<- EventInfo, e Event) (diff eventDiff) {
|
|
wp[c] |= e
|
|
diff[0] = wp[nil]
|
|
diff[1] = diff[0] | e
|
|
wp[nil] = diff[1] &^ omit
|
|
// Strip diff from internal events.
|
|
diff[0] &^= internal
|
|
diff[1] &^= internal
|
|
if diff[0] == diff[1] {
|
|
return none
|
|
}
|
|
return
|
|
}
|
|
|
|
func (wp watchpoint) Del(c chan<- EventInfo, e Event) (diff eventDiff) {
|
|
wp[c] &^= e
|
|
if wp[c] == 0 {
|
|
delete(wp, c)
|
|
}
|
|
diff[0] = wp[nil]
|
|
delete(wp, nil)
|
|
if len(wp) != 0 {
|
|
// Recalculate total event set.
|
|
for _, e := range wp {
|
|
diff[1] |= e
|
|
}
|
|
wp[nil] = diff[1] &^ omit
|
|
}
|
|
// Strip diff from internal events.
|
|
diff[0] &^= internal
|
|
diff[1] &^= internal
|
|
if diff[0] == diff[1] {
|
|
return none
|
|
}
|
|
return
|
|
}
|
|
|
|
func (wp watchpoint) Dispatch(ei EventInfo, extra Event) {
|
|
e := eventmask(ei, extra)
|
|
if !matches(wp[nil], e) {
|
|
return
|
|
}
|
|
for ch, eset := range wp {
|
|
if ch != nil && matches(eset, e) {
|
|
select {
|
|
case ch <- ei:
|
|
default: // Drop event if receiver is too slow
|
|
dbgprintf("dropped %s on %q: receiver too slow", ei.Event(), ei.Path())
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
func (wp watchpoint) Total() Event {
|
|
return wp[nil] &^ internal
|
|
}
|
|
|
|
func (wp watchpoint) IsRecursive() bool {
|
|
return wp[nil]&recursive != 0
|
|
}
|