"fontversion" used to be modified to sort out fonts as a technique.
But that lost the original purpose to do the version control between
releases.
This change adds the dedicated property into the cache.
Fixes https://gitlab.freedesktop.org/fontconfig/fontconfig/-/issues/226
XML tools interpret “fonts.dtd” as a relative path.
Unfortunately, that can not work now that the configuration is spread over
multiple system-dependant directories, without a common relative path to this
file. And, an absolute path can not be defined in a system-independant way.
System independance is a requirement to share config files between systems.
Therefore, replace the broken relative path by a formal URN, that will work the
same way on all systems, without network access.
This makes the DTD registerable with commands like:
$ xmlcatalog --noout --add system \
"urn:fontconfig:fonts.dtd" \
"file:///usr/share/xml/fontconfig/fonts.dtd" \
/etc/xml/catalog
That enables easy config file checking:
$ xmllint --loaddtd ${config_file} >/dev/null
The UUID files would be placed in each font directory to provide the
unique cache name, independent of path, for that directory. The UUID
files are undesireable for a couple of reasons:
1) They must be placed in the font directories to be useful. This
requires modifying the font directories themselves, introducing
potential visible timestamp changes when running multiple
applications, and makes the cache processing inconsistent between
applications with permission to write to the font directories and
applications without such permission.
2) The UUID contents were generated randomly, which makes the font
cache not reproducible across multiple runs.
One proposed fix for 2) is to make the UUID dependent on the font
directory path, but once we do that, we can simply use the font
directory path itself as the key as the original MD5-based font cache
naming mechanism did.
The goal of the UUID file mechanism was to fix startup time of
flatpaks; as the font path names inside the flatpak did not match the
font path names in the base system, the font cache would need to be
reconstructed the first time the flatpak was launched.
The new mechanism for doing this is to allow each '<dir>' element in
the configuration include a 'map' attribute. When looking for a cache
file for a particular directory, if the directory name starts with the
contents of the <dir> element, that portion of the name will be
replaced with the value of the 'map' attribute.
Outside of the flatpak, nothing need change -- fontconfig will build
cache files using real directory names.
Inside the flatpak, the custom fonts.conf file will now include
mappings such as this:
<dir map="/usr/share/fonts">/run/host/fonts</dir>
When scanning the directory /run/host/fonts/ttf, fontconfig will
use the name /usr/share/fonts/ttf as the source for building the cache
file name.
The existing FC_FILE replacement code used for the UUID-based
implementation continues to correctly adapt font path names seen by
applications.
v2:
Leave FcDirCacheCreateUUID stub around to avoid removing
public API function.
Document 'map' attribute of <dir> element in
fontconfig-user.sgml
Suggested-by: Akira TAGOH <akira@tagoh.org>
Signed-off-by: Keith Packard <keithp@keithp.com>
Whilst working on the Reproducible Builds[0] effort, we noticed that
fontconfig generates unreproducible cache files.
This is due to fc-cache uses the modification timestamps of each
directory in the "checksum" and "checksum_nano" members of the _FcCache
struct. This is so that it can identify which cache files are valid
and/or require regeneration.
This patch changes the behaviour of the checksum calculations to prefer
the value of the SOURCE_DATE_EPOCH[1] environment variable over the
directory's own mtime. This variable can then be exported by build
systems to ensure reproducible output.
If SOURCE_DATE_EPOCH is not set or is newer than the mtime of the
directory, the existing behaviour is unchanged.
This work was sponsored by Tails[2].
[0] https://reproducible-builds.org/
[1] https://reproducible-builds.org/specs/source-date-epoch/
[2] https://tails.boum.org/
just setting FC_MATCH=3 shows a lot of information and hard to keep on track for informamtion
which is really necessary to see. to use this more effectively, added FC_DBG_MATCH_FILTER to
see for what one really want to see. it takes a comma-separated-list of object names.
If you want to see family name only, try like this:
FC_DBG_MATCH_FILTER=family FC_DEBUG=4096 fc-match
debugging output will be filtered out and see family only in the result.
Add two edit mode, "delete" and "delete_all".
what values are being deleted depends on <test> as documented.
if the target object is same to what is tested, matching value there
will be deleted. otherwise all of values in the object will be deleted.
so this would means both edit mode will not take any expressions.
e.g.
Given that the testing is always true here, the following rules:
<match>
<test name="foo" compare="eq">
<string>bar</string>
</test>
<edit name="foo" mode="delete"/>
</match>
will removes "bar" string from "foo" object. and:
<match>
<test name="foo" compare="eq">
<string>foo</string>
</test>
<edit name="bar" mode="delete"/>
</match>
will removes all of values in "bar" object.
Warn if the multiple values is set to <test>, including the case of
in <alias> because the behavior isn't intuitive since so many users
is asking for a help to get things working for their expectation.
Use multiple <match>s or <alias>es for OR operator and
multiple <test>s for AND operator.
Allows reading configuration files, fonts and cache files from
the directories where the XDG Base Directory Specification defines.
the old directories are still in the configuration files for
the backward compatibility.
Add a new attribute `ignore-blanks' to <test>.
When this is set to "true", any blanks in the string will be ignored
on comparison. This takes effects for compare="eq" or "not_eq" only.
Also changed the behavior of the comparison on <alias> too.
Stop using mmap() if the cache file is stored on NFS.
also added FONTCONFIG_USE_MMAP environment variable to enforce the use of
or not the use of mmap(2) regardless of what the filesystem the cache files
are stored on.
Akira TAGOH
Ondrej Balaz
Alan Coopersmith
ratijas
Nicolas Mailhot
Keith Packard
Chris Lamb
Tom Anderson
Behdad Esfahbod
Brad Hards