1 files changed, 101 insertions, 0 deletions
diff --git a/vendor/github.com/byzantine-lab/dexon-consensus/common/event.go b/vendor/github.com/byzantine-lab/dexon-consensus/common/event.go
new file mode 100644
index 000000000..4e4e23bf3
--- /dev/null
+++ b/vendor/github.com/byzantine-lab/dexon-consensus/common/event.go
@@ -0,0 +1,101 @@
+// Copyright 2018 The dexon-consensus Authors
+// This file is part of the dexon-consensus library.
+//
+// The dexon-consensus library is free software: you can redistribute it
+// and/or modify it under the terms of the GNU Lesser General Public License as
+// published by the Free Software Foundation, either version 3 of the License,
+// or (at your option) any later version.
+//
+// The dexon-consensus library is distributed in the hope that it will be
+// useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
+// General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the dexon-consensus library. If not, see
+// <http://www.gnu.org/licenses/>.
+
+package common
+
+import (
+	"container/heap"
+	"sync"
+)
+
+type heightEventFn func(uint64)
+
+type heightEvent struct {
+	h  uint64
+	fn heightEventFn
+}
+
+// heightEvents implements a Min-Heap structure.
+type heightEvents []heightEvent
+
+func (h heightEvents) Len() int           { return len(h) }
+func (h heightEvents) Less(i, j int) bool { return h[i].h < h[j].h }
+func (h heightEvents) Swap(i, j int)      { h[i], h[j] = h[j], h[i] }
+func (h *heightEvents) Push(x interface{}) {
+	*h = append(*h, x.(heightEvent))
+}
+func (h *heightEvents) Pop() interface{} {
+	old := *h
+	n := len(old)
+	x := old[n-1]
+	*h = old[0 : n-1]
+	return x
+}
+
+// Event implements the Observer pattern.
+type Event struct {
+	heightEvents     heightEvents
+	heightEventsLock sync.Mutex
+}
+
+// NewEvent creates a new event instance.
+func NewEvent() *Event {
+	he := heightEvents{}
+	heap.Init(&he)
+	return &Event{
+		heightEvents: he,
+	}
+}
+
+// RegisterHeight to get notified on a specific height.
+func (e *Event) RegisterHeight(h uint64, fn heightEventFn) {
+	e.heightEventsLock.Lock()
+	defer e.heightEventsLock.Unlock()
+	heap.Push(&e.heightEvents, heightEvent{
+		h:  h,
+		fn: fn,
+	})
+}
+
+// NotifyHeight and trigger function callback.
+func (e *Event) NotifyHeight(h uint64) {
+	fns := func() (fns []heightEventFn) {
+		e.heightEventsLock.Lock()
+		defer e.heightEventsLock.Unlock()
+		if len(e.heightEvents) == 0 {
+			return
+		}
+		for h >= e.heightEvents[0].h {
+			he := heap.Pop(&e.heightEvents).(heightEvent)
+			fns = append(fns, he.fn)
+			if len(e.heightEvents) == 0 {
+				return
+			}
+		}
+		return
+	}()
+	for _, fn := range fns {
+		fn(h)
+	}
+}
+
+// Reset clears all pending event
+func (e *Event) Reset() {
+	e.heightEventsLock.Lock()
+	defer e.heightEventsLock.Unlock()
+	e.heightEvents = heightEvents{}
+}