HTX_FL_FRAGMENTED flag is now set on an HTX message when it is
fragmented. It happens when an HTX block is removed in the middle of the
message and flagged as unused. HTX_FL_FRAGMENTED flag is removed when all
data are removed from the message or when the message is defragmented.
Note that some optimisations are still possible because the flag can be
avoided in other situations. For instance when the last header of a bodyless
message is removed.
The EOM block may be removed. The HTX_FL_EOM flags is enough. Most of time,
to know if the end of the message is reached, we just need to have an empty
HTX message with HTX_FL_EOM flag set. It may also be detected when the last
block of a message with HTX_FL_EOM flag is manipulated.
Removing EOM blocks simplifies the HTX message filling. Indeed, there is no
more edge problems when the message ends but there is no more space to write
the EOM block. However, some part are more tricky. Especially the
compression filter or the FCGI mux. The compression filter must finish the
compression on the last DATA block. Before it was performed on the EOM
block, an extra DATA block with the checksum was added. Now, we must detect
the last DATA block to be sure to finish the compression. The FCGI mux on
its part must be sure to reserve the space for the empty STDIN record on the
last DATA block while this record was inserted on the EOM block.
The H2 multiplexer is probably the part that benefits the most from this
change. Indeed, it is now fairly easier to known when to set the ES flag.
The HTX documentaion has been updated accordingly.
Add an HTX start-line flag and its counterpart into the HTTP message to
track the presence of the Upgrade option into the Connection header. This
way, without parsing the Connection header again, it will be easy to know if
a client asks for a protocol upgrade and if the server agrees to do so. It
will also be easy to perform some conformance checks when a
101-switching-protocols is received.
Surprisingly there were still a number of [0] definitions for variable
sized arrays in certain structures all over the code. We need to use
VAR_ARRAY instead of zero to accommodate various compilers' preferences,
as zero was used only on old ones and tends to report errors on new ones.
The HTX_FL_EOI flag must now be set on a HTX message when no more data are
expected. Most of time, it must be set before adding the EOM block. Thus, if
there is no space for the EOM, there is still an information to know all data
were received and pushed in the HTX message. There is only an exception for the
HTTP replies (deny, return...). For these messages, the flag is set after all
blocks are pushed in the message, including the EOM block, because, on error,
we remove all inserted data.
Most of the file was a large set of HTX elements manipulation functions
and few types, so splitting them allowed to further reduce dependencies
and shrink the build time. Doing so revealed that a few files (h2.c,
mux_pt.c) needed haproxy/buf.h and were previously getting it through
htx.h. They were fixed.
