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// Copyright 2015 CNI 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 disk
import (
"os"
"syscall"
)
// FileLock wraps os.File to be used as a lock using flock
type FileLock struct {
f *os.File
}
// NewFileLock opens file/dir at path and returns unlocked FileLock object
func NewFileLock(path string) (*FileLock, error) {
f, err := os.Open(path)
if err != nil {
return nil, err
}
return &FileLock{f}, nil
}
// Close closes underlying file
func (l *FileLock) Close() error {
return l.f.Close()
}
// Lock acquires an exclusive lock
func (l *FileLock) Lock() error {
return syscall.Flock(int(l.f.Fd()), syscall.LOCK_EX)
}
// Unlock releases the lock
func (l *FileLock) Unlock() error {
return syscall.Flock(int(l.f.Fd()), syscall.LOCK_UN)
}
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