65 lines
1.1 KiB
Go
65 lines
1.1 KiB
Go
package iio
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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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"sync"
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)
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type DiskTeeReader struct {
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io.ReaderAt
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io.Closer
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io.Reader
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m sync.Mutex
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fo int64
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fr *os.File
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to int64
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tr io.Reader
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}
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func NewDiskTeeReader(r io.Reader) (*DiskTeeReader, error) {
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fr, err := ioutil.TempFile("", "dtb_tmp")
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if err != nil {
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return nil, err
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}
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tr := io.TeeReader(r, fr)
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return &DiskTeeReader{fr: fr, tr: tr}, nil
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}
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func (dtr *DiskTeeReader) ReadAt(p []byte, off int64) (int, error) {
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dtr.m.Lock()
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defer dtr.m.Unlock()
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tb := off + int64(len(p))
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if tb > dtr.fo {
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w, err := io.CopyN(ioutil.Discard, dtr.tr, tb-dtr.fo)
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dtr.to += w
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if err != nil && err != io.EOF {
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return 0, err
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}
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}
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n, err := dtr.fr.ReadAt(p, off)
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dtr.fo += int64(n)
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return n, err
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}
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func (dtr *DiskTeeReader) Read(p []byte) (n int, err error) {
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dtr.m.Lock()
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defer dtr.m.Unlock()
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// use directly tee reader here
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n, err = dtr.tr.Read(p)
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dtr.to += int64(n)
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return
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}
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func (dtr *DiskTeeReader) Close() error {
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if err := dtr.fr.Close(); err != nil {
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return err
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}
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return os.Remove(dtr.fr.Name())
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}
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