OnlineLibrary

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package util
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import (
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	"os"
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	"path/filepath"
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)
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const tmp_suffix = ".tmp"
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type SecureFile struct {
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	path      string
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	corrupted bool
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	f         *os.File
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}
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func CreateSecureFile(path string) (*SecureFile, error) {
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	if err := os.MkdirAll(filepath.Dir(path), os.ModeDir); err != nil {
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		return nil, err
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	}
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	f, err := os.Create(path + tmp_suffix)
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	if err != nil {
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		return nil, err
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	}
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	sf := new(SecureFile)
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	sf.path = path
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	sf.f = f
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	return sf, nil
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}
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func (sf *SecureFile) Write(p []byte) (int, error) {
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	n, err := sf.f.Write(p)
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	if err != nil {
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		sf.corrupted = true
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	}
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	return n, err
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}
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func (sf *SecureFile) Corrupted() {
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	sf.corrupted = true
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}
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func (sf *SecureFile) Close() error {
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	err := sf.f.Close()
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	tmp_path := sf.f.Name()
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	if sf.corrupted || err != nil {
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		// Temporary file is corrupted. Trying to remove it
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		os.Remove(tmp_path)
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		return err
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	}
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	// Just replace the original file with a temporary one
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	return os.Rename(tmp_path, sf.path)
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}
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