Hulk did something

[bytom/vapor.git] / vendor / github.com / prometheus / prometheus / util / flock / flock_unix.go

diff --git a/vendor/github.com/prometheus/prometheus/util/flock/flock_unix.go b/vendor/github.com/prometheus/prometheus/util/flock/flock_unix.go
new file mode 100644 (file)
index 0000000..7d71f8f
--- /dev/null
+++ b/vendor/github.com/prometheus/prometheus/util/flock/flock_unix.go
@@ -0,0 +1,54 @@
+// Copyright 2016 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build darwin dragonfly freebsd linux netbsd openbsd
+
+package flock
+
+import (
+       "os"
+       "syscall"
+)
+
+type unixLock struct {
+       f *os.File
+}
+
+func (l *unixLock) Release() error {
+       if err := l.set(false); err != nil {
+               return err
+       }
+       return l.f.Close()
+}
+
+func (l *unixLock) set(lock bool) error {
+       how := syscall.LOCK_UN
+       if lock {
+               how = syscall.LOCK_EX
+       }
+       return syscall.Flock(int(l.f.Fd()), how|syscall.LOCK_NB)
+}
+
+func newLock(fileName string) (Releaser, error) {
+       f, err := os.OpenFile(fileName, os.O_RDWR|os.O_CREATE, 0644)
+       if err != nil {
+               return nil, err
+       }
+       l := &unixLock{f}
+       err = l.set(true)
+       if err != nil {
+               f.Close()
+               return nil, err
+       }
+       return l, nil
+}