56 lines
1.3 KiB
Go
56 lines
1.3 KiB
Go
package http3
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import (
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"io"
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"github.com/quic-go/quic-go/quicvarint"
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)
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// CapsuleType is the type of the capsule.
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type CapsuleType uint64
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type exactReader struct {
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R *io.LimitedReader
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}
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func (r *exactReader) Read(b []byte) (int, error) {
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n, err := r.R.Read(b)
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if r.R.N > 0 {
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return n, io.ErrUnexpectedEOF
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}
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return n, err
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}
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// ParseCapsule parses the header of a Capsule.
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// It returns an io.LimitedReader that can be used to read the Capsule value.
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// The Capsule value must be read entirely (i.e. until the io.EOF) before using r again.
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func ParseCapsule(r quicvarint.Reader) (CapsuleType, io.Reader, error) {
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ct, err := quicvarint.Read(r)
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if err != nil {
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if err == io.EOF {
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return 0, nil, io.ErrUnexpectedEOF
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}
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return 0, nil, err
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}
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l, err := quicvarint.Read(r)
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if err != nil {
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if err == io.EOF {
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return 0, nil, io.ErrUnexpectedEOF
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}
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return 0, nil, err
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}
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return CapsuleType(ct), &exactReader{R: io.LimitReader(r, int64(l)).(*io.LimitedReader)}, nil
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}
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// WriteCapsule writes a capsule
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func WriteCapsule(w quicvarint.Writer, ct CapsuleType, value []byte) error {
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b := make([]byte, 0, 16)
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b = quicvarint.Append(b, uint64(ct))
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b = quicvarint.Append(b, uint64(len(value)))
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if _, err := w.Write(b); err != nil {
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return err
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}
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_, err := w.Write(value)
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return err
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}
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