Tip: How to avoid fc-cache as root?

[Danilo Šegan <dsegan gmx net>]

I've found out what's wrong (partly) with fontconfig, and why it 
requires running fc-cache as root.

When we call fc-list, it updates our local file "~/.fonts.cache-1" with 
the results of a scan of all our directories listed in "fonts.conf". For 
example, if "fonts.conf" contains 
"<dir>/usr/X11R6.6/lib/X11/fonts</dir>", then we get a list of all the 
fonts and directories found in it. The problem is that it doesn't run 
recursively, but rather just one level deep, so subdirectories found 
don't get scanned, rather just stored with their timestamps (this causes 
the trouble, see below).

One would expect that the second run of fc-list would correct the 
situation, but there's a single problem with that: stored "times" are 
the same as ctime and/or atime of listed subdirectories. So, if we have 
root access, we might do "su -c fc-cache", or "for i in 
/usr/X11R6.6/lib/X11/fonts/*; do if [ -d $i ]; then touch $i/fonts.dir; 
fi;done".

But if we want to follow the tradition of user-space GARNOME install, 
we'd have to edit all the timestamps of subdirectories in generated 
"~/.fonts.cache-1" (or whatever is set as <cache> in fonts.conf), but we 
must not change the timestamps of first-level directories (those 
mentioned in fonts.conf), because it would rescan that dir, and again 
wouldn't go any deeper.

So, here's the Python script fcfix (if you don't have Python, how did 
you manage to compile GARNOME?) that accepts the filename as a first 
argument, and all other  arguments are considered directories of which 
no timestamp changes are wanted. No error checking, so be careful, and 
use at your own risk. All the timestamps that are changed are decreased 
for 1 (second).

WARNING: This is not a solution, this is an ugly *HACK*.


#-fcfix--CUT-HERE---------------------------------------------------
#!/usr/bin/python
import sys

if len(sys.argv)>1:
    onfile=1
    f=open(sys.argv[1],"r")
    lines=f.readlines()
    f.close()
    f=open(sys.argv[1],"w")
else:
    print "Usage: fcfix <fonts.cache file> <dir>*\n"
    sys.exit(-1)

for line in lines:
    parts=line.split(" ")
    if parts[3]=='".dir"\n' and not(parts[0][1:-1] in sys.argv[1:]):
        parts[2]=str(int(parts[2])-1)
    line=" ".join(parts)
    f.write(line)
#-fcfix---------------------------------------------------CUT-HERE--


Which directories would you put on command line depends on the settings 
in your fonts.conf, my example session follows:

subota u 01:24: ~ $ rm ~/.fonts.cache-1
subota u 01:24: ~ $ fc-list
subota u 01:24: ~ $ fcfix ~/.fonts.cache-1 /usr/X11R6.6/lib/X11/fonts 
~/.fonts
subota u 01:24: ~ $ fc-list | wc -l
    230
subota u 01:26: ~ $

Be sure to substitute all the paths I use with paths from your 
fonts.conf, and (if you added <cache> directive to fonts.conf) the name 
.fonts.cache-1 with appropriate name.


When I get some more spare time, I'll look into fontconfig source, and 
try to find the real solution. Or, someone might tip the Keith Packard 
about this behaviour: it simply couldn't be what is desired of fc-list, 
so it must be a bug. As it seems after quick glance, 
fontconfig/src/fccache.c is the place to check, but some things are done 
in fcdir.c.

To summarize: fc-list works incorrectly if initially started with no 
cache file. Once you correct it, all's fine.

So, maybe we should generate one .fonts.cache-1 for the user with his 
directories and timestamps far in the past (maybe 0?)for GARNOME.


Hope this helps shed some light on the subject, so any comments? Should 
a bug be filed (if so, where?) or should it be first corrected, then 
filed :)

Danilo