74 lines
1.4 KiB
Go
74 lines
1.4 KiB
Go
package incrt
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import (
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"io"
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"time"
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logging "github.com/ipfs/go-log/v2"
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)
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var log = logging.Logger("incrt")
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var now = time.Now
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type ReaderDeadline interface {
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Read([]byte) (int, error)
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SetReadDeadline(time.Time) error
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}
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type incrt struct {
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rd ReaderDeadline
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waitPerByte time.Duration
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wait time.Duration
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maxWait time.Duration
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}
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// New creates an Incremental Reader Timeout, with minimum sustained speed of
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// minSpeed bytes per second and with maximum wait of maxWait
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func New(rd ReaderDeadline, minSpeed int64, maxWait time.Duration) io.Reader {
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return &incrt{
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rd: rd,
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waitPerByte: time.Second / time.Duration(minSpeed),
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wait: maxWait,
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maxWait: maxWait,
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}
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}
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type errNoWait struct{}
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func (err errNoWait) Error() string {
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return "wait time exceeded"
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}
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func (err errNoWait) Timeout() bool {
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return true
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}
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func (crt *incrt) Read(buf []byte) (int, error) {
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start := now()
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if crt.wait == 0 {
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return 0, errNoWait{}
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}
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err := crt.rd.SetReadDeadline(start.Add(crt.wait))
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if err != nil {
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log.Debugf("unable to set deadline: %+v", err)
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}
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n, err := crt.rd.Read(buf)
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crt.rd.SetReadDeadline(time.Time{})
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if err == nil {
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dur := now().Sub(start)
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crt.wait -= dur
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crt.wait += time.Duration(n) * crt.waitPerByte
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if crt.wait < 0 {
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crt.wait = 0
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}
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if crt.wait > crt.maxWait {
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crt.wait = crt.maxWait
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}
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}
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return n, err
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}
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