github.com/df-mc/goleveldb@v1.1.9/leveldb/storage/file_storage_plan9.go (about)

     1  // Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
     2  // All rights reserved.
     3  //
     4  // Use of this source code is governed by a BSD-style license that can be
     5  // found in the LICENSE file.
     6  
     7  package storage
     8  
     9  import (
    10  	"os"
    11  )
    12  
    13  type plan9FileLock struct {
    14  	f *os.File
    15  }
    16  
    17  func (fl *plan9FileLock) release() error {
    18  	return fl.f.Close()
    19  }
    20  
    21  func newFileLock(path string, readOnly bool) (fl fileLock, err error) {
    22  	var (
    23  		flag int
    24  		perm os.FileMode
    25  	)
    26  	if readOnly {
    27  		flag = os.O_RDONLY
    28  	} else {
    29  		flag = os.O_RDWR
    30  		perm = os.ModeExclusive
    31  	}
    32  	f, err := os.OpenFile(path, flag, perm)
    33  	if os.IsNotExist(err) {
    34  		f, err = os.OpenFile(path, flag|os.O_CREATE, perm|0644)
    35  	}
    36  	if err != nil {
    37  		return
    38  	}
    39  	fl = &plan9FileLock{f: f}
    40  	return
    41  }
    42  
    43  func rename(oldpath, newpath string) error {
    44  	if _, err := os.Stat(newpath); err == nil {
    45  		if err := os.Remove(newpath); err != nil {
    46  			return err
    47  		}
    48  	}
    49  
    50  	return os.Rename(oldpath, newpath)
    51  }
    52  
    53  func syncDir(name string) error {
    54  	f, err := os.Open(name)
    55  	if err != nil {
    56  		return err
    57  	}
    58  	defer f.Close()
    59  	if err := f.Sync(); err != nil {
    60  		return err
    61  	}
    62  	return nil
    63  }