// TODO(prashant): Use a small buffer and then flush it when it's full.
func writeHeaders(w io.Writer, headers map[string]string) error {
// Calculate the size of the buffer that we need.
size := 2
for k, v := range headers {
size += 4 /* size of key/value lengths */
size += len(k) + len(v)
}
buf := make([]byte, size)
writeBuffer := typed.NewWriteBuffer(buf)
writeBuffer.WriteUint16(uint16(len(headers)))
for k, v := range headers {
writeBuffer.WriteLen16String(k)
writeBuffer.WriteLen16String(v)
}
if err := writeBuffer.Err(); err != nil {
return err
}
// Safety check to ensure the bytes written calculation is correct.
if writeBuffer.BytesWritten() != size {
return fmt.Errorf("writeHeaders size calculation wrong, expected to write %v bytes, only wrote %v bytes",
size, writeBuffer.BytesWritten())
}
_, err := writeBuffer.FlushTo(w)
return err
}
func (ch fragmentChannel) newFragment(initial bool, checksum Checksum) (*writableFragment, error) {
wbuf := typed.NewWriteBuffer(make([]byte, testFragmentSize))
fragment := new(writableFragment)
fragment.flagsRef = wbuf.DeferByte()
wbuf.WriteSingleByte(byte(checksum.TypeCode()))
fragment.checksumRef = wbuf.DeferBytes(checksum.Size())
fragment.checksum = checksum
fragment.contents = wbuf
return fragment, wbuf.Err()
}
// newFragment creates a new fragment for marshaling into
func (w *reqResWriter) newFragment(initial bool, checksum Checksum) (*writableFragment, error) {
message := w.messageForFragment(initial)
// Create the frame
frame := w.conn.framePool.Get()
frame.Header.ID = w.mex.msgID
frame.Header.messageType = message.messageType()
// Write the message into the fragment, reserving flags and checksum bytes
wbuf := typed.NewWriteBuffer(frame.Payload[:])
fragment := new(writableFragment)
fragment.frame = frame
fragment.flagsRef = wbuf.DeferByte()
if err := message.write(wbuf); err != nil {
return nil, err
}
wbuf.WriteByte(byte(checksum.TypeCode()))
fragment.checksumRef = wbuf.DeferBytes(checksum.Size())
fragment.checksum = checksum
fragment.contents = wbuf
return fragment, wbuf.Err()
}