telebit/decoder.go

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package telebit
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import (
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"fmt"
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"io"
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"os"
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"git.rootprojects.org/root/telebit/dbg"
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)
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// Decoder handles a Reader stream containing mplexy-encoded clients
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type Decoder struct {
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in io.Reader
bufferSize int
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}
// NewDecoder returns an initialized Decoder
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func NewDecoder(rin io.Reader) *Decoder {
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return &Decoder{
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in: rin,
bufferSize: defaultBufferSize,
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}
}
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// Decode will call WriteMessage as often as addressable data exists,
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// reading up to bufferSize (default 8192) at a time
// (header + data, though headers are often sent separately from data).
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func (d *Decoder) Decode(out Router) error {
p := NewParser(out)
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rx := make(chan []byte)
rxErr := make(chan error)
go func() {
for {
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b := make([]byte, d.bufferSize)
n, err := d.in.Read(b)
if dbg.Debug {
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fmt.Fprintf(os.Stderr, "[debug] [decoder] [srv] Tunnel read %d %s\n", n, dbg.Trunc(b, n))
}
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if n > 0 {
rx <- b[:n]
}
if nil != err {
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fmt.Fprintf(os.Stderr, "[decoder] [srv] Tunnel read err: %s\n", err)
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rxErr <- err
return
}
}
}()
for {
select {
case b := <-rx:
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n, err := p.Write(b)
if dbg.Debug {
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fmt.Fprintf(os.Stderr, "[debug] [decoder] [srv] Tunnel write %d %d %s\n", n, len(b), dbg.Trunc(b, len(b)))
}
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// TODO BUG: handle when 'n' bytes written is less than len(b)
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if nil != err {
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fmt.Fprintf(os.Stderr, "[decoder] [srv] Tunnel write err: %s\n", err)
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// an error to write represents an unrecoverable error,
// not just a downstream client error
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//d.in.Close()
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return err
}
case err := <-rxErr:
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//d.in.Close()
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if io.EOF == err {
// it can be assumed that err will close though, right
return nil
}
return err
}
}
}