80 lines
1.8 KiB
Go
80 lines
1.8 KiB
Go
package tape
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import (
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"archive/tar"
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"bufio"
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"os"
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"github.com/pojntfx/stfs/internal/controllers"
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"github.com/pojntfx/stfs/internal/counters"
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)
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func OpenTapeWriteOnly(drive string, recordSize int, overwrite bool) (tw *tar.Writer, isRegular bool, cleanup func(dirty *bool) error, err error) {
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stat, err := os.Stat(drive)
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if err == nil {
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isRegular = stat.Mode().IsRegular()
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} else {
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if os.IsNotExist(err) {
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isRegular = true
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} else {
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return nil, false, nil, err
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}
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}
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var f *os.File
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if isRegular {
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f, err = os.OpenFile(drive, os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0600)
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if err != nil {
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return nil, false, nil, err
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}
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// No need to go to end manually due to `os.O_APPEND`
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} else {
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f, err = os.OpenFile(drive, os.O_APPEND|os.O_WRONLY, os.ModeCharDevice)
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if err != nil {
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return nil, false, nil, err
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}
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if !overwrite {
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// Go to end of tape
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if err := controllers.GoToEndOfTape(f); err != nil {
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return nil, false, nil, err
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}
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}
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}
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var bw *bufio.Writer
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var counter *counters.CounterWriter
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if isRegular {
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tw = tar.NewWriter(f)
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} else {
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bw = bufio.NewWriterSize(f, controllers.BlockSize*recordSize)
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counter = &counters.CounterWriter{Writer: bw, BytesRead: 0}
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tw = tar.NewWriter(counter)
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}
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return tw, isRegular, func(dirty *bool) error {
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// Only write the trailer if we wrote to the archive
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if *dirty {
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if err := tw.Close(); err != nil {
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return err
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}
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if !isRegular {
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if controllers.BlockSize*recordSize-counter.BytesRead > 0 {
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// Fill the rest of the record with zeros
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if _, err := bw.Write(make([]byte, controllers.BlockSize*recordSize-counter.BytesRead)); err != nil {
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return err
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}
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}
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if err := bw.Flush(); err != nil {
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return err
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}
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}
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}
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return f.Close()
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}, nil
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}
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