Headers related to ws or h2 are now elided if the ws or h2 role
is not enabled for build. In addition, a new build-time option
LWS_WITH_HTTP_UNCOMMON_HEADERS on by default allows removal of
less-common http headers to shrink the parser footprint.
Minilex is adapted to produce 8 different versions of the lex
table, chosen at build-time according to which headers are
included in the build.
If you don't need the unusual headers, or aren't using h2 or ws,
this chops down the size of the ah and the rodata needed to hold
the parsing table from 87 strings / pointers to 49, and the
parsing table from 1177 to 696 bytes.
This should be a NOP for h2 support and only affects internal
apis. But it lets us reuse the working and reliable h2 mux
arrangements directly in other protocols later, and share code
so building for h2 + new protocols can take advantage of common
mux child handling struct and code.
Break out common mux handling struct into its own type.
Convert all uses of members that used to be in wsi->h2 to wsi->mux
Audit all references to the members and break out generic helpers
for anything that is useful for other mux-capable protocols to
reuse wsi->mux related features.
Until now lws only parses headers it knows at build-time from its
prebuilt lexical analyzer.
This adds an on-by-default cmake option and a couple of apis
to also store and query "custom", ie, unknown-to-lws headers.
A minimal example is also provided.
At the moment it only works on h1, h2 support needs improvements
to the hpack implementation.
Since it bloats ah memory usage compared to without it if custom
headers are present, the related code and ah footprint can be
disabled with the cmake option LWS_WITH_CUSTOM_HEADERS, but it's
on by default normally. ESP32 platform disables it.
https://github.com/warmcat/libwebsockets/pull/1499
