func (r *rawV4EventReader) getHeaderBuffer() *bufio2.LookAheadBuffer {
if r.headerBuffer == nil { // New event
r.headerBuffer = bufio2.NewLookAheadBufferUsing(
r.src,
r.rawHeaderBuffer)
}
return r.headerBuffer
}
func (r *rawV4EventReader) NextEvent() (Event, error) {
if r.isClosed {
return nil, errors.New("Event reader is closed")
}
if r.nextEvent == nil { // new event
r.nextEvent = &RawV4Event{
sourceName: r.srcName,
sourcePosition: r.logPosition,
}
}
if r.nextEvent.data == nil { // still parsing the header
headerBytes, err := r.getHeaderBuffer().PeekAll()
if err != nil {
return nil, err
}
_, err = readLittleEndian(headerBytes, &r.nextEvent.header)
if err != nil {
return nil, err
}
bodySize := int(r.nextEvent.EventLength()) - sizeOfBasicV4EventHeader
if bodySize < 0 { // should never happen
return nil, errors.New("Invalid event size")
}
r.nextEvent.data = make(
[]byte,
r.nextEvent.EventLength(),
r.nextEvent.EventLength())
copied := copy(r.nextEvent.data, headerBytes)
if copied != sizeOfBasicV4EventHeader { // should never happen
panic("Failed to copy header")
}
r.bodyBuffer = bufio2.NewLookAheadBufferUsing(
r.src,
r.nextEvent.data[sizeOfBasicV4EventHeader:])
}
_, err := r.bodyBuffer.PeekAll()
if err != nil {
return nil, err
}
// consume the constructed event and clean the look ahead buffers
event := r.nextEvent
r.nextEvent = nil
r.headerBuffer = nil
r.bodyBuffer = nil
r.logPosition += int64(event.EventLength())
return event, nil
}