'salt' attribute affects a cache filename to generate different name from directory name.
This is useful when sharing caches with host on sandbox and/or give a filename differently:
<dir salt="randomdata">/usr/share/fonts</dir>
<remap-dir as-path="/usr/share/fonts" salt="salt for /usr/share/fonts on host">/run/host/fonts</remap-dir>
Applications can read caches as-is for fonts on /run/host/fonts where is mounted from host.
and write a cache for their own fonts on /usr/share/fonts with different name.
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>
On a file system with one-second time stamps, extra delays are needed
between cache modification operations to ensure that fontconfig isn't
fooled.
And, when the timestamps are checked correctly, we need to make sure
that FcConfigUptoDate returns false whenever we change a font
directory, so separate that out from the call to reinitialize the core
config.
Signed-off-by: Keith Packard <keithp@keithp.com>
This causes a failure when evaluating $OSTYPE on systems which do not
set that variable (everything but Msys/MinGW)
Signed-off-by: Keith Packard <keithp@keithp.com>
This saves the value of FONTCONFIG_SYSROOT in the config instead of
having to call getenv every time we need this value.
This also uses 'realpath' to construct a canonical path to sysroot,
eliminating symlinks and relative path names.
Signed-off-by: Keith Packard <keithp@keithp.com>
The generic family of 'system-ui' name is being proposed in a draft of next CSS Fonts.
This would be nice to support in fontconfig too.
https://www.w3.org/TR/css-fonts-4/
All non trivial users of FontConfig must use FcConfigGetSysRoot to
resolve file properties in patterns. In order to support sysroot the
filename in the file property must be relative to the sysroot, but the
value of the file property in a pattern is directly exposed, making it
impossible for FontConfig to resolve the filename itself transparently.
Otherwise, there would be build errors in the following 2 cases:
* define HAVE_POSIX_FADVISE
Or:
* undef HAVE_POSIX_FADVISE
Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Akira TAGOH
Keith Packard
Ben Wagner
Robert Yang