wehub-resource-sync
47 lines
1.3 KiB
Go
47 lines
1.3 KiB
Go
package modeladmin
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import (
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"fmt"
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"os"
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"path/filepath"
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)
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// writeFileAtomic writes data to path via a sibling temp file followed by
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// an os.Rename. If the process is killed mid-write, the original file is
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// preserved intact instead of being truncated/partial — which os.WriteFile
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// + O_TRUNC|O_WRONLY would leave behind.
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//
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// The temp file lives in the same directory so the rename is atomic on the
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// same filesystem. The leading "." keeps it out of `ls` output. Cleanup
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// runs on every error path so stray temps don't accumulate when the
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// destination directory is read-only or out of inodes.
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func writeFileAtomic(path string, data []byte, mode os.FileMode) error {
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dir := filepath.Dir(path)
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f, err := os.CreateTemp(dir, "."+filepath.Base(path)+".tmp-*")
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if err != nil {
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return fmt.Errorf("create temp file: %w", err)
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}
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tmp := f.Name()
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cleanup := func() { _ = os.Remove(tmp) }
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if _, err := f.Write(data); err != nil {
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_ = f.Close()
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cleanup()
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return fmt.Errorf("write temp file: %w", err)
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}
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if err := f.Chmod(mode); err != nil {
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_ = f.Close()
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cleanup()
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return fmt.Errorf("chmod temp file: %w", err)
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}
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if err := f.Close(); err != nil {
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cleanup()
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return fmt.Errorf("close temp file: %w", err)
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}
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if err := os.Rename(tmp, path); err != nil {
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cleanup()
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return fmt.Errorf("rename temp file: %w", err)
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}
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return nil
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}
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