After reviewing codebase, only queue for DATA frames requires
priorities. Other frames can be replaced multiple linear queues.
Replacing priority queue with linear queue allows us to simplify
codebase a bit; for example, now nghttp2_session.next_seq is gone.
It is generally useful to know what is the cause of the error. Since
we expose HPACK API, it is friendly to tell application the
insufficient buffer size is a culprit.
Now incoming data is processed in very small buffer (up to 8 bytes)
using state machine. GOAWAY debug data can get to 16K - 1, and we
don't have callback for it. Since we don't want to buffer that
amount of data just for debugging, we currently discard it.
This change also makes parse_error callback not function.
It probably be removed from API.
This stream inflater can inflate incoming header block in streaming
fashion. Currently, we buffer up single name/value pair, but we chose
far more smaller buffer size than HTTP/2 frame size.
Tatsuhiro Tsujikawa
Alexis La Goutte