When I originally wrote hb-ft, FreeType objects did not support reference
counting. As such, hb_ft_face_create() and hb_ft_font_create() had a
"destroy" callback and client was responsible for making sure FT_Face is
kept around as long as the hb-font/face are alive.
However, since this was not clearly documented, some clienets didn't
correctly did that. In particular, some clients assumed that it's safe
to destroy FT_Face and then hb_face_t. This, indeed, used to work, until
45fd9424c7, which make face destroy access
font tables.
Now, I fixed that issue in 395b35903e since
the access was not needed, but the problem remains that not all clients
handle this correctly. See:
https://bugs.freedesktop.org/show_bug.cgi?id=86300
Fortunately, FT_Reference_Face() was added to FreeType in 2010, and so we
can use it now. Originally I wanted to change hb_ft_face_create() and
hb_ft_font_create() to reference the face if destroy==NULL was passed in.
That would improve pretty much all clients, with little undesired effects.
Except that FreeType itself, when compiled with HarfBuzz support, calls
hb_ft_font_create() with destroy==NULL and saves the resulting hb-font on
the ft-face (why does it not free it immediately?). Making hb-face
reference ft-face causes a cycling reference there. At least, that's my
current understanding.
At any rate, a cleaner approach, even if it means all clients will need a
change, is to introduce brand new API. Which this commit does.
Some comments added to hb-ft.h, hoping to make future clients make better
choices.
Fixes https://bugs.freedesktop.org/show_bug.cgi?id=75299
As in building for Android / iPhone. Only set it if
struct{char} alignment is not 1.
NOT tested on an actual Arm architecture. Guess we'll know
when this makes it to people's build bots.
They've been disabled for a while and no one cared. We're past
the point to need them for testing, and if we ever need to
resurrect them again, well, they're in git graveyard somewhere.
Behdad Esfahbod
Konstantin Ritt
Dominik Röttsches