Made sure clear_output is always paired with swap_buffers.
Trying to see if we can move towards RAII-like buffer iterators
instead of the buffer keeping an iterator internally.
Previous error-handling philosophy was that user doesn't need to
immediately know whether operation failed. But as can be seen after
we added malloc-failing fuzzing, there's just so many places in the
code that a failure of these operations needs to be mitigated before
further operations. So I'm moving towards returning success here,
and possibly making it nodiscard.
The immutable objects are a concept only enforced by the C API.
So move checks only to that region.
This does assume that the rest of the code is careful not getting
into these internal methods on immutable objects, which something
we do, but have no way of enforcing (currently).
.
`0xC2A0` was used, for some reasons. It's not really a problem, but Qt Creator
constatly trying to replace them with regular spaces, so I have to edit those
files separately.
Fixes this -fno-sanitize-recover=undefined check,
/buffer/positions/empty: hb-buffer.cc:327:11: runtime error: null pointer passed as argument 1, which is declared to never be null
/usr/include/string.h:60:62: note: nonnull attribute specified here
#0 0x4cf31c in hb_buffer_t::clear_positions() /home/user/code/harfbuzz/src/hb-buffer.cc:327:3
#1 0x4d4dd4 in hb_buffer_get_glyph_positions /home/user/code/harfbuzz/src/hb-buffer.cc:1418:13
#2 0x4cb553 in test_buffer_positions /home/user/code/harfbuzz/test/api/test-buffer.c:305:3
#3 0x7f324187bf49 (/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x72f49)
#4 0x7f324187be7a (/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x72e7a)
#5 0x7f324187be7a (/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x72e7a)
#6 0x7f324187c121 in g_test_run_suite (/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x73121)
#7 0x7f324187c140 in g_test_run (/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x73140)
#8 0x4c8bd3 in hb_test_run /home/user/code/harfbuzz/test/api/./hb-test.h:88:10
#9 0x4c8bd3 in main /home/user/code/harfbuzz/test/api/test-buffer.c:884:10
#10 0x7f324086db96 in __libc_start_main /build/glibc-OTsEL5/glibc-2.27/csu/../csu/libc-start.c:310
#11 0x41e919 in _start (/home/user/code/harfbuzz/test/api/test-buffer+0x41e919)
`hb_language_from_string` accepts not only ISO 639 but also BCP 47. Not
all ISO 639 codes are valid BCP 47 tags but the function does not accept
overlong language subtags anyway.