99 lines
2.1 KiB
Go
99 lines
2.1 KiB
Go
package atomicfile
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import (
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"crypto/rand"
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"encoding/hex"
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"fmt"
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"os"
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"path/filepath"
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"runtime"
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)
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func Write(path string, data []byte, perm os.FileMode) error {
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directory := filepath.Dir(path)
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root, err := os.OpenRoot(directory)
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if err != nil {
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return err
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}
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defer root.Close()
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return WriteRoot(root, filepath.Base(path), data, perm)
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}
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func WriteRoot(root *os.Root, name string, data []byte, perm os.FileMode) error {
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if root == nil || name == "" || name == "." || filepath.IsAbs(name) {
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return fmt.Errorf("invalid atomic file path")
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}
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directory := filepath.Dir(name)
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base := filepath.Base(name)
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token := make([]byte, 16)
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if _, err := rand.Read(token); err != nil {
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return err
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}
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temporaryName := filepath.Join(directory, "."+base+"-"+hex.EncodeToString(token))
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temporary, err := root.OpenFile(temporaryName, os.O_WRONLY|os.O_CREATE|os.O_EXCL, perm)
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if err != nil {
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return err
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}
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closed := false
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committed := false
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defer func() {
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if !closed {
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_ = temporary.Close()
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}
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if !committed {
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_ = root.Remove(temporaryName)
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}
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}()
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if err = temporary.Chmod(perm); err != nil {
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return err
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}
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written, err := temporary.Write(data)
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if err != nil {
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return err
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}
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if written != len(data) {
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return fmt.Errorf("short atomic file write: wrote %d of %d bytes", written, len(data))
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}
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if err = temporary.Sync(); err != nil {
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return err
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}
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if err = temporary.Close(); err != nil {
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closed = true
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return err
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}
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closed = true
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if err = root.Rename(temporaryName, name); err != nil {
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return err
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}
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committed = true
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if err = root.Chmod(name, perm); err != nil {
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return err
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}
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return syncRootDirectory(root, directory)
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}
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func SyncDirectory(path string) error {
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if runtime.GOOS == "windows" {
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return nil
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}
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root, err := os.OpenRoot(path)
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if err != nil {
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return err
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}
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defer root.Close()
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return syncRootDirectory(root, ".")
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}
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func syncRootDirectory(root *os.Root, name string) error {
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if runtime.GOOS == "windows" {
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return nil
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}
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directory, err := root.Open(name)
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if err != nil {
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return err
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}
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defer directory.Close()
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return directory.Sync()
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}
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