40 lines
742 B
Go
40 lines
742 B
Go
package continuity
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import (
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"io"
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"io/ioutil"
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"os"
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"path/filepath"
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)
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// atomicWriteFile writes data to a file by first writing to a temp
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// file and calling rename.
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func atomicWriteFile(filename string, r io.Reader, rf RegularFile) error {
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f, err := ioutil.TempFile(filepath.Dir(filename), ".tmp-"+filepath.Base(filename))
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if err != nil {
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return err
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}
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err = os.Chmod(f.Name(), rf.Mode())
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if err != nil {
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f.Close()
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return err
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}
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n, err := io.Copy(f, r)
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if err == nil && n < rf.Size() {
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f.Close()
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return io.ErrShortWrite
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}
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if err != nil {
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f.Close()
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return err
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}
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if err := f.Sync(); err != nil {
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f.Close()
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return err
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}
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if err := f.Close(); err != nil {
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return err
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}
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return os.Rename(f.Name(), filename)
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}
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