Magic-Mirror/gecko-dev
1
0
Fork 0
mirror of https://github.com/mozilla/gecko-dev.git synced 2024-11-25 22:01:30 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Bug 853169 - Make qcms precache reference counts threadsafe/atomic. r=jrmuizel

Browse Source
This commit is contained in:
Joe Drew 2013-03-21 23:09:37 -04:00
parent 3d94635306
commit 90942b6b22
3 changed files with 34 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
gfx/qcms/qcms.h
View File

@ -40,6 +40,12 @@ sale, use or other dealings in this Software without written
authorization from SunSoft Inc.
******************************************************************/
/*
* QCMS, in general, is not threadsafe. However, it should be safe to create
* profile and transformation objects on different threads, so long as you
* don't use the same objects on different threads at the same time.
*/
/*
* Color Space Signatures
* Note that only icSigXYZData and icSigLabData are valid

18
gfx/qcms/qcmsint.h
View File

@ -284,6 +284,24 @@ void qcms_transform_data_rgba_out_lut_altivec(qcms_transform *transform,
extern qcms_bool qcms_supports_iccv4;
#ifdef _MSC_VER
long __cdecl _InterlockedIncrement(long volatile *);
long __cdecl _InterlockedDecrement(long volatile *);
#pragma intrinsic(_InterlockedIncrement)
#pragma intrinsic(_InterlockedDecrement)
#define qcms_atomic_increment(x) _InterlockedIncrement((long volatile *)&x)
#define qcms_atomic_decrement(x) _InterlockedDecrement((long volatile*)&x)
#else
#define qcms_atomic_increment(x) __sync_add_and_fetch(&x, 1)
#define qcms_atomic_decrement(x) __sync_sub_and_fetch(&x, 1)
#endif
#ifdef NATIVE_OUTPUT
# define RGB_OUTPUT_COMPONENTS 4
# define RGBA_OUTPUT_COMPONENTS 4

12
gfx/qcms/transform.c
View File

@ -886,9 +886,17 @@ static void qcms_transform_data_rgb_out_linear(qcms_transform *transform, unsign
}
#endif
/*
* If users create and destroy objects on different threads, even if the same
* objects aren't used on different threads at the same time, we can still run
* in to trouble with refcounts if they aren't atomic.
*
* This can lead to us prematurely deleting the precache if threads get unlucky
* and write the wrong value to the ref count.
*/
static struct precache_output *precache_reference(struct precache_output *p)
{
p->ref_count++;
qcms_atomic_increment(p->ref_count);
return p;
}
@ -902,7 +910,7 @@ static struct precache_output *precache_create()
void precache_release(struct precache_output *p)
{
if (--p->ref_count == 0) {
if (qcms_atomic_decrement(p->ref_count) == 0) {
free(p);
}
}