The nghttp2 library itself is still h2-14. To experiment with the
implementations to require h2-16 to test new features (e.g.,
prioritization), nghttp, nghttpx, nghttpd and h2load now support h2-16
as well as h2-14. Cleartext HTTP Upgrade is still limited to h2-14
however.
Now the number of -v option specifies verbosity level. Current all
verbose output are turned on for at lest one -v option, except for the
debug output for each data chunk which is only turned on more than one
-v options.
It is not used by library for a while. It could be used to pass
unsupported extension frames to application, but its interface
requires library to buffer entire frame, which we'd like to avoid.
For unsupported extension frames, we will add new callbacks which does
not require buffering if they are required.
h2-14 now allows extensions to define new error codes. To allow
application callback to access such error codes, we uses uint32_t as
error_code type for structs and function parameters. Previously we
treated unknown error code as INTERNAL_ERROR, but this change removes
this and unknown error code is passed to application callback as is.
To make it possible to add new callbacks without bumping so name, we
decided to hide details of nghttp2_session_callbacks. We provide
setter like functions to set individual callback function.
Now concatenating header values with 0x00 as delimiter is not
necessary because HPACK reference set is removed and the order of
header field fed into HPACK encoder is preserved when they are
decoded.
Previously, we use evbuffer_pullup(buf, -1) to linearize the memory
region and it may cause buffer copy. To avoid this, we use the return
value of evbuffer_get_contiguous_space() as 2nd parameter. According
to the libevent manual, by doing so evbuffer_pullup() will not copy or
modify any data in evbuffer.