[PATCH v3 0/1] MR2081: Support relocatable fontconfig cache

[catsout (＠catsout)]

For flatpak:  
```
bind mount:
/run/host/fonts      <- /usr/share/fonts
/run/host/user-fonts <- ~/.local/share/fonts

/run/host/fonts-cache      <- /usr/lib/fontconfig/cache
/run/host/user-fonts-cache <- ~/.cache/fontconfig
```

For fontconfig:   
https://bugs.freedesktop.org/show_bug.cgi?id=101889  
https://github.com/flatpak/flatpak/issues/589  
It supports relocatable cache.  
```
FcConfigGetFontDirs( config )  -> /run/host/user-fonts/test,...
FcDirCacheRead( /run/host/user-fonts/test, ... ) -> FcCacheCopySet -> pattern
FcPatternGetString( pattern, FC_FILE, 0, &filename ) -> ~/.local/share/fonts/test/test.ttf
```

For wine:  
``` 
FcPatternGetString -> unix_name -> add_unix_face( unix_name, ... )  
```
The valid file path for flatpak is `/run/host/user-fonts/test/test.ttf`.  
`~/.local/share/fonts/test/test.ttf` does not exist in flatpak sandbox.

Add a check for this, and switch to right path.

Test:  
```
flatpak install org.winehq.Wine
LANG=zh_CN.UTF-8 flatpak run org.winehq.Wine winecfg
```
![image](/uploads/6679b2771e3400b02903faa308a1d1c5/image.png)

--
  v3: Support relocatable fontconfig cache

https://gitlab.winehq.org/wine/wine/-/merge_requests/2081

[PATCH v3 1/1] Support relocatable fontconfig cache

[catsout]

From: catsout

---
 dlls/win32u/freetype.c | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

diff --git a/dlls/win32u/freetype.c b/dlls/win32u/freetype.c
index fd402758daa..6ac6670fd89 100644
--- a/dlls/win32u/freetype.c
+++ b/dlls/win32u/freetype.c
@@ -1524,11 +1524,12 @@ static FcPattern *create_family_pattern( const char *name, FcPattern **cached )
     return ret;
 }

-static void fontconfig_add_font( FcPattern *pattern, UINT flags )
+static void fontconfig_add_font( FcPattern *pattern, UINT flags, const char *cache_dir )
 {
-    const char *unix_name, *format;
+    char *unix_name;
+    const char *format, *basename;
     WCHAR *dos_name;
-    FcBool scalable;
+    FcBool scalable, reloc;
     DWORD aa_flags;
     int face_index;

@@ -1564,9 +1565,23 @@ static void fontconfig_add_font( FcPattern *pattern, UINT flags )
     if (pFcPatternGetInteger( pattern, FC_INDEX, 0, &face_index ) != FcResultMatch)
         face_index = 0;

+    reloc = FcFalse;
+    if (strncmp( unix_name, cache_dir, strlen(cache_dir) ) != 0 && access( unix_name, F_OK ) != 0) {
+        basename = strrchr( unix_name, '/' );
+        basename = ( basename ? basename+1 : unix_name );
+        unix_name = malloc( strlen(cache_dir) + strlen(basename) + 2 );
+        if (unix_name) {
+            sprintf( unix_name, "%s/%s", cache_dir, basename );
+            reloc = FcTrue;
+        }
+    }
+
     dos_name = get_dos_file_name( unix_name );
     add_unix_face( unix_name, dos_name, NULL, 0, face_index, flags, NULL );
     free( dos_name );
+
+    if (reloc == FcTrue)
+      free( unix_name );
 }

static void init_fontconfig(void)
@@ -1648,7 +1663,7 @@ static void fontconfig_add_fonts_from_dir_list( FcConfig *config, FcStrList *dir

if (!(font_set = pFcCacheCopySet( cache ))) goto done;
         for (i = 0; i < font_set->nfont; i++)
-            fontconfig_add_font( font_set->fonts[i], flags );
+            fontconfig_add_font( font_set->fonts[i], flags , (const char *)dir );
         pFcFontSetDestroy( font_set );
         font_set = NULL;

[Huw Davies (＠huw)]

So basically the path of `FC_FILE` in fontconfig under flatpak is incorrect?  This doesn't sound like something Wine should have to work around.

[catsout (＠catsout)]

On Thu Feb 16 14:36:25 2023 +0000, Huw Davies wrote:
> So basically the path of `FC_FILE` in fontconfig under flatpak is
> incorrect?  This doesn't sound like something Wine should have to work around.

`FC_FILE` is stored in the font cache file.  
flatpak mounts the cache into the sandbox.  
To avoid recreating the cache, maybe have the fontconfig lib check and return the changed `FC_FILE` value?

[Huw Davies (＠huw)]

> To avoid recreating the cache, maybe have the fontconfig lib check and return the changed `FC_FILE` value?

That would seem to be a better place for the fix.

[Huw Davies (＠huw)]

> > To avoid recreating the cache, maybe have the fontconfig lib check and return the changed `FC_FILE` value?
>
> That would seem to be a better place for the fix.

Either that, or flatpak should copy the font cache and modify its contents to fix up the paths or something.

[PATCH v3 0/1] MR2081: Support relocatable fontconfig cache - closed

[Huw Davies (＠huw)]

This merge request was closed by Huw Davies.

[Huw Davies (＠huw)]

Closing as this isn't something that Wine should need to deal with.