This replaces the existing binary search with two perfect hash functions
for the composition and the decomposition in the backend code, at the
cost of slightly-larger binaries there (35kB in libpgcommon_srv.a). Per
the measurements done, this improves the speed of the recomposition and
decomposition by up to 30~40 times for the NFC and NFKC conversions,
while all other operations get at least 40% faster. This is not as
"good" as what libicu has, but it closes the gap a lot as per the
feedback from Daniel Verite.
The decomposition table remains the same, getting used for the binary
search in the frontend code, where we care more about the size of the
libraries like libpq over performance as this gets involved only in code
paths related to the SCRAM authentication. In consequence, note that
the perfect hash function for the recomposition needs to use a new
inverse lookup array back to to the existing decomposition table.
The size of all frontend deliverables remains unchanged, even with
--enable-debug, including libpq.
Author: John Naylor
Reviewed-by: Michael Paquier, Tom Lane
Discussion: https://postgr.es/m/CAFBsxsHUuMFCt6-pU+oG-F1==CmEp8wR+O+bRouXWu6i8kXuqA@mail.gmail.com
Includes some manual cleanup of places that pgindent messed up,
most of which weren't per project style anyway.
Notably, it seems some people didn't absorb the style rules of
commit c9d297751, because there were a bunch of new occurrences
of function calls with a newline just after the left paren, all
with faulty expectations about how the rest of the call would get
indented.
It previously only supported NFKC, for use by SASLprep. This expands
the API to offer the choice of all four normalization forms. Right
now, there are no internal users of the forms other than NFKC.
Reviewed-by: Daniel Verite <daniel@manitou-mail.org>
Reviewed-by: Andreas Karlsson <andreas@proxel.se>
Discussion: https://www.postgresql.org/message-id/flat/c1909f27-c269-2ed9-12f8-3ab72c8caf7a@2ndquadrant.com
An important step of SASLprep normalization, is to convert the string to
Unicode normalization form NFKC. Unicode normalization requires a fairly
large table of character decompositions, which is generated from data
published by the Unicode consortium. The script to generate the table is
put in src/common/unicode, as well test code for the normalization.
A pre-generated version of the tables is included in src/include/common,
so you don't need the code in src/common/unicode to build PostgreSQL, only
if you wish to modify the normalization tables.
The SASLprep implementation depends on the UTF-8 functions from
src/backend/utils/mb/wchar.c. So to use it, you must also compile and link
that. That doesn't change anything for the current users of these
functions, the backend and libpq, as they both already link with wchar.o.
It would be good to move those functions into a separate file in
src/commmon, but I'll leave that for another day.
No documentation changes included, because there is no details on the
SCRAM mechanism in the docs anyway. An overview on that in the protocol
specification would probably be good, even though SCRAM is documented in
detail in RFC5802. I'll write that as a separate patch. An important thing
to mention there is that we apply SASLprep even on invalid UTF-8 strings,
to support other encodings.
Patch by Michael Paquier and me.
Discussion: https://www.postgresql.org/message-id/CAB7nPqSByyEmAVLtEf1KxTRh=PWNKiWKEKQR=e1yGehz=wbymQ@mail.gmail.com
Michael Paquier
Tom Lane
Peter Eisentraut
Bruce Momjian
Peter Eisentraut
Heikki Linnakangas