Re: pg_ls_tmpdir to show directories and shared filesets (and pg_ls_*)

On Tue, Mar 17, 2020 at 10:21:48AM +0100, Fabien COELHO wrote:
>
> About v13, seens as one patch:
>
> Function "pg_ls_dir_metadata" documentation suggests a variable number of
> arguments with brackets, but parameters are really mandatory.

Fixed, and added tests on 1 and 3 arg versions of both pg_ls_dir() and
pg_ls_dir_metadata().

It seems like the only way to make variable number of arguments is is with
multiple entries in pg_proc.dat, one for each "number of" arguments. Is that
right ?

> The example in the documentation could be better indented. Also, ISTM that
> there are two implicit laterals (format & pg_ls_dir_recurse) that I would
> make explicit. I'd use the pcs alias explicitely. I'd use meaningful aliases
> (eg ts instead of b, …).

> On reflection, I think that a boolean "isdir" column is a bad idea because
> it is not extensible. I'd propose to switch to the standard "ls" approach of
> providing the type as one character: '-' for regular, 'd' for directory, 'l'
> for link, 's' for socket, 'c' for character special…

I think that's outside the scope of the patch, since I'd want to change
pg_stat_file; that's where I borrowed "isdir" from, for consistency.

Note that both LS_DIR_HISTORIC and LS_DIR_MODERN include LS_DIR_SKIP_SPECIAL,
so only pg_ls_dir itself show specials, so they way to do it would be to 1)
change pg_stat_file to expose the file's "type", 2) use pg_ls_dir() AS a,
lateral pg_stat_file(a) AS b, 3) then consider also changing LS_DIR_MODERN and
all the existing pg_ls_*.

> ISTM that "lstat" is not available on windows, which suggests to call "stat"
> always, and then "lstat" on un*x and pg ports stuff on win.

I believe that's handled here.
src/include/port/win32_port.h:#define lstat(path, sb) stat(path, sb)

> I'm wondering about the restriction on directories only. Why should it not
> work on a file? Can it be easily extended to work on a simple file? If so,
> it could be just "pg_ls".

I think that's a good idea, except it doesn't fit with what the code does:
AllocDir() and ReadDir(). Instead, use pg_stat_file() for that.

Hm, I realized that the existing pg_ls_dir_metadata was skipping links to dirs,
since !ISREG(). So changed to use both stat() and lstat().

--
Justin