syncthing/internal/lamport/clock.go

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// Copyright (C) 2014 Jakob Borg and Contributors (see the CONTRIBUTORS file).
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//
// This program is free software: you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the Free
// Software Foundation, either version 3 of the License, or (at your option)
// any later version.
//
// This program 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 General Public License for
// more details.
//
// You should have received a copy of the GNU General Public License along
// with this program. If not, see <http://www.gnu.org/licenses/>.
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// Package lamport implements a simple Lamport Clock for versioning
package lamport
import "sync"
var Default = Clock{}
type Clock struct {
val uint64
mut sync.Mutex
}
func (c *Clock) Tick(v uint64) uint64 {
c.mut.Lock()
if v > c.val {
c.val = v + 1
c.mut.Unlock()
return v + 1
} else {
c.val++
v = c.val
c.mut.Unlock()
return v
}
}