Hulk did something

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

diff --git a/vendor/github.com/prometheus/prometheus/util/flock/flock.go b/vendor/github.com/prometheus/prometheus/util/flock/flock.go
new file mode 100644 (file)
index 0000000..5dc22a2
--- /dev/null
+++ b/vendor/github.com/prometheus/prometheus/util/flock/flock.go
@@ -0,0 +1,46 @@
+// 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.
+
+// Package flock provides portable file locking. It is essentially ripped out
+// from the code of github.com/syndtr/goleveldb. Strange enough that the
+// standard library does not provide this functionality. Once this package has
+// proven to work as expected, we should probably turn it into a separate
+// general purpose package for humanity.
+package flock
+
+import (
+       "os"
+       "path/filepath"
+)
+
+// Releaser provides the Release method to release a file lock.
+type Releaser interface {
+       Release() error
+}
+
+// New locks the file with the provided name. If the file does not exist, it is
+// created. The returned Releaser is used to release the lock. existed is true
+// if the file to lock already existed. A non-nil error is returned if the
+// locking has failed. Neither this function nor the returned Releaser is
+// goroutine-safe.
+func New(fileName string) (r Releaser, existed bool, err error) {
+       if err = os.MkdirAll(filepath.Dir(fileName), 0755); err != nil {
+               return
+       }
+
+       _, err = os.Stat(fileName)
+       existed = err == nil
+
+       r, err = newLock(fileName)
+       return
+}