Re: [PATCH] psql formatting patch (round 2)

[Please CC any replies, thanks]

This patch has the same effect as the last one except it now uses the
PQmblen and PQdsplen functions exported by libpq as suggested by Tom.
This clears a lot of stuff from psql's mbprint.c which is a good thing.
This means it should work for all for encodings (though I can't say I
tested them all).

The PQdsplen function in libpq has been improved so it can actually
work and provide the necessary information for formatting. That file
(wchar.c) is actually shared with the backend but the backend doesn't
use the dsplen functions, so it does add some dead code (on top of what
was already there).

Note: this changes the PQdsplen function, it can now return zero or
minus one which was not possible before. It doesn't appear anyone is
actually using the functions other than psql but it is a change. The
functions are not actually documentated anywhere so it's not like we're
breaking a defined interface. The new semantics follow the Unicode
standard.

The other uses of PQdsplen in psql (in ReportSyntaxErrorPosition) would
seem to be slightly affected by the change, except it's not clear how
psql should react to control characters in the string it's trying to
print...

Patch available at:
http://svana.org/kleptog/pgsql/psql-format.patch

Comments welcome,

Have a nice day,
--
Martijn van Oosterhout <kleptog(at)svana(dot)org> http://svana.org/kleptog/
> Patent. n. Genius is 5% inspiration and 95% perspiration. A patent is a
> tool for doing 5% of the work and then sitting around waiting for someone
> else to do the other 95% so you can sue them.

Modified patch attached and applied. I made some style changes and had
some merge conflicts because wchar.c has changed since 8.1.

The change to libpq's PQdsplen() seems like a good one and I will
mention it in the release notes.

---------------------------------------------------------------------------

Martijn van Oosterhout wrote:
-- Start of PGP signed section.
> [Please CC any replies, thanks]
>
> This patch has the same effect as the last one except it now uses the
> PQmblen and PQdsplen functions exported by libpq as suggested by Tom.
> This clears a lot of stuff from psql's mbprint.c which is a good thing.
> This means it should work for all for encodings (though I can't say I
> tested them all).
>
> The PQdsplen function in libpq has been improved so it can actually
> work and provide the necessary information for formatting. That file
> (wchar.c) is actually shared with the backend but the backend doesn't
> use the dsplen functions, so it does add some dead code (on top of what
> was already there).
>
> Note: this changes the PQdsplen function, it can now return zero or
> minus one which was not possible before. It doesn't appear anyone is
> actually using the functions other than psql but it is a change. The
> functions are not actually documentated anywhere so it's not like we're
> breaking a defined interface. The new semantics follow the Unicode
> standard.
>
> The other uses of PQdsplen in psql (in ReportSyntaxErrorPosition) would
> seem to be slightly affected by the change, except it's not clear how
> psql should react to control characters in the string it's trying to
> print...
>
> Patch available at:
> http://svana.org/kleptog/pgsql/psql-format.patch
>
> Comments welcome,
>
> Have a nice day,
> --
> Martijn van Oosterhout <kleptog(at)svana(dot)org> http://svana.org/kleptog/
> > Patent. n. Genius is 5% inspiration and 95% perspiration. A patent is a
> > tool for doing 5% of the work and then sitting around waiting for someone
> > else to do the other 95% so you can sue them.

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--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
+ Christ can be your backup. | Newtown Square, Pennsylvania 19073

Oh, one more thing. The only user-visible change I saw in the
regression tests is that a SELECT * on a table where all the columns
have been dropped doesn't return a blank line like before. This seems
like a step forward.

Usage example:

test=> SELECT '1\n2\n3', 'a\nb\nc';
?column? | ?column?
----------+----------
1 | a
2 : b
3 : c
(1 row)

---------------------------------------------------------------------------

Martijn van Oosterhout wrote:
-- Start of PGP signed section.
> [Please CC any replies, thanks]
>
> This patch has the same effect as the last one except it now uses the
> PQmblen and PQdsplen functions exported by libpq as suggested by Tom.
> This clears a lot of stuff from psql's mbprint.c which is a good thing.
> This means it should work for all for encodings (though I can't say I
> tested them all).
>
> The PQdsplen function in libpq has been improved so it can actually
> work and provide the necessary information for formatting. That file
> (wchar.c) is actually shared with the backend but the backend doesn't
> use the dsplen functions, so it does add some dead code (on top of what
> was already there).
>
> Note: this changes the PQdsplen function, it can now return zero or
> minus one which was not possible before. It doesn't appear anyone is
> actually using the functions other than psql but it is a change. The
> functions are not actually documentated anywhere so it's not like we're
> breaking a defined interface. The new semantics follow the Unicode
> standard.
>
> The other uses of PQdsplen in psql (in ReportSyntaxErrorPosition) would
> seem to be slightly affected by the change, except it's not clear how
> psql should react to control characters in the string it's trying to
> print...
>
> Patch available at:
> http://svana.org/kleptog/pgsql/psql-format.patch
>
> Comments welcome,
>
> Have a nice day,
> --
> Martijn van Oosterhout <kleptog(at)svana(dot)org> http://svana.org/kleptog/
> > Patent. n. Genius is 5% inspiration and 95% perspiration. A patent is a
> > tool for doing 5% of the work and then sitting around waiting for someone
> > else to do the other 95% so you can sue them.

[ Attachment, skipping... ]
-- End of PGP section, PGP failed!

--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
+ Christ can be your backup. | Newtown Square, Pennsylvania 19073