[OE-core] [RFC][PATCH 3/3] fontcache: allow to pass extra parameters and environment to fc-cache

[Martin Jansa]

* this can be useful for passing extra parameters, pass
  -v by default to see what's going on in do_rootfs
* we need to use this for extra parameter we implemented
  in fontconfig:
  --ignore-mtime always use cache file regardless of font directory mtime
  because the checksum of fontcache generated in do_rootfs
  doesn't match with /usr/share/fonts directory as seen on
  target device causing fontconfig to re-create the cache
  when fontconfig is used for first time or worse create
  new cache in every user's home directory when /usr/
  filesystem is read only and cache cannot be updated.

  Running FC_DEBUG=16 fc-cache -v on such device shows:
  FcCacheTimeValid dir "/usr/share/fonts" cache checksum 1441207803 dir checksum 1441206149
* my guess is that the checksum is different, because pseudo
  (which is unloaded when running qemuwrapper) or because some
  influence of running the rootfs under qemu.

Signed-off-by: Martin Jansa <Martin.Jansa at gmail.com>
---
 meta/classes/fontcache.bbclass                | 19 +++++++++++++++----
 scripts/postinst-intercepts/update_font_cache |  4 ++--
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/meta/classes/fontcache.bbclass b/meta/classes/fontcache.bbclass
index d122387..1dd1418 100644
--- a/meta/classes/fontcache.bbclass
+++ b/meta/classes/fontcache.bbclass
@@ -9,12 +9,23 @@ inherit qemu
 FONT_PACKAGES ??= "${PN}"
 FONT_EXTRA_RDEPENDS ?= "fontconfig-utils"
 FONTCONFIG_CACHE_DIR ?= "${localstatedir}/cache/fontconfig"
+FONTCONFIG_CACHE_PARAMS ?= "-v"
+# You can change this to e.g. FC_DEBUG=16 to debug fc-cache issues,
+# something has to be set, because qemuwrapper is using this variable after -E
+# multiple variables aren't allowed because for qemu they are separated
+# by comma and in -n "$D" case they should be separated by space
+FONTCONFIG_CACHE_ENV ?= "FC_DEBUG=1"
 fontcache_common() {
-if [ "x$D" != "x" ] ; then
-	$INTERCEPT_DIR/postinst_intercept update_font_cache ${PKG} mlprefix=${MLPREFIX} bindir=${bindir} \
-		libdir=${libdir} base_libdir=${base_libdir} fontconfigcachedir=${FONTCONFIG_CACHE_DIR}
+if [ -n "$D" ] ; then
+	$INTERCEPT_DIR/postinst_intercept update_font_cache ${PKG} mlprefix=${MLPREFIX} \
+		'bindir="${bindir}'" \
+		'libdir="${libdir}'" \
+		'base_libdir="${base_libdir}'" \
+		'fontconfigcachedir="${FONTCONFIG_CACHE_DIR}'" \
+		'fontconfigcacheparams="${FONTCONFIG_CACHE_PARAMS}'" \
+		'fontconfigcacheenv="${FONTCONFIG_CACHE_ENV}'"
 else
-	fc-cache
+	${FONTCONFIG_CACHE_ENV} fc-cache ${FONTCONFIG_CACHE_PARAMS}
 fi
 }
 
diff --git a/scripts/postinst-intercepts/update_font_cache b/scripts/postinst-intercepts/update_font_cache
index c8c6018..0deab3c 100644
--- a/scripts/postinst-intercepts/update_font_cache
+++ b/scripts/postinst-intercepts/update_font_cache
@@ -1,5 +1,5 @@
 #!/bin/sh
 
-PSEUDO_UNLOAD=1 qemuwrapper -L $D -E LD_LIBRARY_PATH=$D/${libdir}:$D/${base_libdir}\
-					$D${bindir}/fc-cache --sysroot=$D
+PSEUDO_UNLOAD=1 qemuwrapper -L $D -E LD_LIBRARY_PATH=$D/${libdir}:$D/${base_libdir} \
+					-E ${fontconfigcacheenv} $D${bindir}/fc-cache --sysroot=$D ${fontconfigcacheparams}
 chown -R root:root $D${fontconfigcachedir}
-- 
2.5.0