1 files changed, 103 insertions, 0 deletions
diff --git a/Godeps/_workspace/src/github.com/rjeczalik/notify/watchpoint.go b/Godeps/_workspace/src/github.com/rjeczalik/notify/watchpoint.go
new file mode 100644
index 000000000..5afc914f4
--- /dev/null
+++ b/Godeps/_workspace/src/github.com/rjeczalik/notify/watchpoint.go
@@ -0,0 +1,103 @@
+// 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
+}