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stream-rwc.go
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stream-rwc.go
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package srpc
import (
"bytes"
"io"
)
// StreamRwc implements an io.ReadWriteCloser with a srpc.Stream.
type StreamRwc struct {
// Stream is the base stream interface.
Stream
// buf is the incoming data buffer
buf bytes.Buffer
// readMsg is the raw read message
readMsg RawMessage
// writeMsg is the raw write message
writeMsg RawMessage
}
// NewStreamRwc constructs a new stream read write closer.
func NewStreamRwc(strm Stream) *StreamRwc {
rwc := &StreamRwc{Stream: strm}
rwc.readMsg.copy = true
rwc.writeMsg.copy = true
return rwc
}
// Read reads data from the stream to p.
// Implements io.Reader.
func (s *StreamRwc) Read(p []byte) (n int, err error) {
readBuf := p
for len(readBuf) != 0 && err == nil {
var rn int
// if the buffer has data, read from it.
if s.buf.Len() != 0 {
rn, err = s.buf.Read(readBuf)
} else {
if n != 0 {
// if we read data to p already, return now.
break
}
s.readMsg.Clear()
if err := s.Stream.MsgRecv(&s.readMsg); err != nil {
return n, err
}
data := s.readMsg.GetData()
if len(data) == 0 {
continue
}
// read as much as possible directly to the output
copy(readBuf, data)
if len(data) > len(readBuf) {
// we read some of the data, buffer the rest.
rn = len(readBuf)
_, _ = s.buf.Write(data[rn:]) // never returns an error
} else {
// we read all of data
rn = len(data)
}
}
// advance readBuf by rn
n += rn
readBuf = readBuf[rn:]
}
return n, err
}
// Write writes data to the stream.
func (s *StreamRwc) Write(p []byte) (n int, err error) {
s.writeMsg.SetData(p)
err = s.Stream.MsgSend(&s.writeMsg)
s.writeMsg.Clear()
if err != nil {
return 0, err
}
return len(p), nil
}
// _ is a type assertion
var _ io.ReadWriteCloser = ((*StreamRwc)(nil))