atomic: Separate bool and old-value compare-and-exchange

Some implementations only offer one version of compare-and-exchange,
thus we expose both through cairo-atomic, implementing what is missing
through appropriate fallbacks.
*_cmpxchg() now return a boolean (this unbreaks _cairo_atomic_uint_cmpxchg)
*_cmpxchg_return_old() return the old value
Code is updated everywhere to reflect this, by using *_cmpxchg()
wherever the returned value was only tested to check if the exchange
had really taken place.

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 2 insertions, 2 deletions

diff --git a/src/cairo-atomic.c b/src/cairo-atomic.c
index 60d8f0021..4347be12d 100644
--- a/src/cairo-atomic.c
+++ b/src/cairo-atomic.c
@@ -62,7 +62,7 @@ _cairo_atomic_int_dec_and_test (int *x)
 }
 
 int
-_cairo_atomic_int_cmpxchg (int *x, int oldv, int newv)
+_cairo_atomic_int_cmpxchg_return_old_impl (int *x, int oldv, int newv)
 {
     int ret;
 
@@ -76,7 +76,7 @@ _cairo_atomic_int_cmpxchg (int *x, int oldv, int newv)
 }
 
 void *
-_cairo_atomic_ptr_cmpxchg (void **x, void *oldv, void *newv)
+_cairo_atomic_ptr_cmpxchg_return_old_impl (void **x, void *oldv, void *newv)
 {
     void *ret;