H3 consolidation: merge client and server code - #9
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The QUIC/HTTP3 server and client were two near-identical files: the read path, the write path, flow control, the ngtcp2/nghttp3 callback bridges and the write loop existed twice, and every fix had to be applied twice, in parallel, to both. A QUIC connection is symmetric, and so is an HTTP/3 stream -- what differs between the roles is only which half of the exchange travels in which direction. So both now share one implementation, phrased in terms of the *incoming* and the *outgoing* message: * http3::Http3Stream (anyhttp/http3_stream.hpp, src/http3_stream.cpp) -- one request/response exchange: read path, write path, header parsing, lifecycle, plus the Http3Reader/Http3Writer adapter templates. Role hooks: on_pseudo_header(), on_headers_complete(), on_failed(), submit_response(). * http3::Http3Session (anyhttp/http3_session.hpp, src/http3_session.cpp) -- one QUIC connection: every callback bridge, write_pkt/write_streams, the timers, flow control, setup_http3(), setup_tls(). Role hooks: handle_error(), send_datagrams(), make_stream(), on_http3_ready(), on_new_cid()/on_remove_cid(). * anyhttp/http3_common.hpp -- make_nv(), log_headers(), the ngtcp2 log callback and the shared constants. What is left in server_impl_udp.cpp is what is genuinely server-side: the TLS server context, the UDP demux (many connections over one socket, a CID table, a strand and a dup()ed fd per session) and the closing/draining bookkeeping. In client_impl_udp.cpp: the TLS client context, the connect()ed socket and its receive loop, wait_ready() and async_submit(). 4902 lines became 3900, of which 2250 are now shared. Making the two sides one implementation also made them behave alike: the client now uses the server's ngtcp2_conn_write_aggregate_pkt2() write path (splitting the buffer by gso_size, without UDP_SEGMENT), both roles register nghttp3's acked_stream_data, both send STOP_SENDING when a reader is dropped early, both support read cancellation, and stream failure reporting goes through one Http3Stream::fail(). The one thing that stayed apart is how a body is handed to nghttp3, now spelled out as WriteMode: the server points nghttp3 straight into the caller's buffer and completes the write on acknowledgement, while the client stages through a bounded copy so that cancelling a write leaves the stream intact. Everything around it is shared. Three bugs found on the way, fixed here: * async_get_response() on a stream that had already failed waited forever, because only a handler installed *before* the failure was ever completed. The stream now remembers why it died and answers a late caller right away. * Write completions ran the application from inside a nghttp3 callback, i.e. from inside ngtcp2: a handler destroying the session there wrote a CONNECTION_CLOSE with a fresh timestamp and the enclosing write pass then continued with its own, stale one, tripping ngtcp2's "conn->log.last_ts <= ts" assertion. Completions are posted now, and write_pkt() stops packing when the connection went away underneath it. * Delivering a response can drop the last reference to its stream, so async_get_response() holds one of its own (found by ASAN). Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Each protocol implementation now lives in files prefixed h1_ (beast), h2_ (nghttp2) and h3_ (ngtcp2/nghttp3), and the protocol libraries no longer leak out of them: <nghttp2/*> is included only by h2_* files, <ngtcp2/*>/<nghttp3/*> only by h3_* ones. Four places needed more than a rename: * formatter.hpp pulled in <nghttp2/nghttp2.h> for the nghttp2_nv formatter, which moves to h2_common.hpp (absorbing nghttp2_common.hpp). * server_impl.cpp / client_impl.cpp instantiated the h1 and h2 session templates themselves. They now go through make_server_session() / make_client_session(), declared in h1_backend.hpp / h2_backend.hpp in terms of asio types only and defined in the backends' own translation units, which are the only ones instantiating those templates. * the server's ALPN callback called nghttp2_select_next_protocol(), replaced by a preference-ordered selection over the ALPN wire format. * Server::Impl held the whole QUIC demux -- UDP socket, receive loop, connection-ID table, an ngtcp2_cid forward declaration. That is now Http3ServerImpl in h3_server.cpp, behind the abstract Http3Server and make_http3_server() in h3_backend.hpp. What is left in Server::Impl is m_http3 plus add_session()/remove_session(), the session registry all three protocols share. Also drops the stray NGHTTP2 link from the server executable. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
The error_code overloads of shutdown()/set_option() now return void, so drop the std::ignore = in front of them. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Replaces the hand-written "[{}] " prefix and log_prefix_ argument with the
mlog* macros in the member functions of h3_session.cpp.
The static ngtcp2/nghttp3 callbacks keep the explicit form: mlog* expands to
an unqualified logPrefix(), which has nothing to bind to there.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Comment wording and formatting only, no behaviour change: - h3_session: half-open range as [dest, dest+destlen[ - h3_backend: reflow the Http3Server comment, "de-multiplexing" - common: section separator before the ReadSome aliases - cspell: sveccnt Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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