Improve legibility of reviewing the generated table, using hex rather than dec

Submitted by: wrowe
Backport: r1754536

Correct T_HTTP_TOKEN_STOP per RFC2068 (2.2) - RFC7230 (3.2.6),
which has always defined 'token' as CHAR or VCHAR - visible USASCII only.
NUL char is also a stop, end of parsing.
Submitted by: wrowe
Backport: r1754538

Be more explicit about NUL in case iscntrl is inconsistent
Submitted by: wrowe
Backport: r1754539

Introduce T_HTTP_CTRLS for efficiently finding non-text chars
Submitted by: wrowe
Backport: r1754540

Introduce ap_scan_http_field_content, ap_scan_http_token
and ap_get_http_token [later reverted] for more efficient
string handling.
Submitted by: wrowe
Backport: r1754541

With NUL as a TOKEN_STOP, this code is more efficient
Submitted by: wrowe
Backport: r1754544

We arrive here for more than one cause; offer a more general statement
Submitted by: wrowe
Backport: r1754547

Strictly observe spec on obs-fold
Submitted by: wrowe
Backport: r1754548

Leave an emphatic TODO per Jeff's observations
Submitted by: trawick
Backport: r1754555

Introduce ap_scan_http_token / ap_scan_http_field_content for a much
more efficient pass through the header text; rather than reparsing
the strings over and over under the HTTP_CONFORMANCE_STRICT fules.

Improve logic and legibility by eliminating multiple repetitive tests
of the STRICT flag, and simply reorder 'classic' behavior first and
this new parser second to simplify the diff. Because of the whitespace
change (which I had wished to dodge), reading this --ignore-all-space
is a whole lot easier. Particularly against 2.4.x branch, which is now
identical in the 'classic' logic flow. Both of which I'll share with dev@
Submitted by: wrowe
Backport: r1754556

Friendly catch by Rüdiger, restore line mis-removed by the previous commit
Submitted by: rpluem
Backport: r1754568

Clean up doubled-'{'
Correct usage for ap_scan_http_token (had used _get_ syntax)
Correct logic, detect no 'token' chars, or missing ':'
Submitted by: wrowe, rpluem
Backport: r1754569,r1754570,r1754577

Replacement solution to identify VCHAR/ASCII symbols, even in EBCDIC.
Looking for someone with an EBCDIC environment to post the output of
the test_char.h generated file for verification.
Submitted by: wrowe
Backport: r1754579

Clean up an edge case where obs-fold continuation preceeds the first header,
as with r1755098, but this time ensure the previous header processing logic 
ensures there was a previous header as identified by jchampion.

This patch restructures the loop for legibility with a loop continuation,
allowing us to flatten all of this hard-to-follow code. The subsequent
patch will be a whitespace-only change for formatting.

Testing len > 0 is redundant when *field is a "\0" and mismatches here,
folded flag was a no-op, unused once we added continue; logic.
Fix these as initially attempted in r1755114.

Improve comments and reflow whitespace.
Submitted by: wrowe
Backport: r1755123,r1755124,r1755125,r1755126

As promised, reduce this logic by net 9 code lines, shifting the burden 
of killing trailing whitespace to the purpose-agnostic read logic.

Whitespace before or after an obs-fold, and before or after a field value
have no semantic purpose at all. Because we are building a buffer for all
folded values, reducing the size of the newly allocated buffer is always
to our advantage.
Submitted by: wrowe
Backport: r1755233

Treat empty obs-fold line as a noop, eliminate all intra-obs-fold excess
whitespace, and observe the 1 SP per obs-folding per spec.
Submitted by: wrowe
Backport: r1755234,r1755235,r1755236

Treat empty obs-fold line as abusive traffic.
Submitted by: wrowe
Backport: r1755263

Stop reflecting irrelevant data to the request error notes, particularly
for abusive and malformed traffic the non-technical consumer of a user-agent
has no control over.

Simply take note where the administrator-configured limits have been exceeded,
that administrator can find details in the error log if desired.
Submitted by: wrowe
Backport: r1755264

Follow up to r1755264.
Don't crash when ap_rgetline() returns a NULL field on ENOSPC.
Submitted by: ylavic
Backport: r1755343

Follow on to r1755264, for the case of merged header length exceptions,
and ensure the field header name is truncated to a sane log width.
Submitted by: wrowe
Backport: r1755744



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x-merge-http-strict@1769649 13f79535-47bb-0310-9956-ffa450edef68