diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/core/SkRefCnt.h | 40 | ||||
| -rw-r--r-- | include/effects/SkColorCubeFilter.h | 1 |
2 files changed, 18 insertions, 23 deletions
diff --git a/include/core/SkRefCnt.h b/include/core/SkRefCnt.h index cf3e385b25..9c62fe2740 100644 --- a/include/core/SkRefCnt.h +++ b/include/core/SkRefCnt.h @@ -10,8 +10,7 @@ #ifndef SkRefCnt_DEFINED #define SkRefCnt_DEFINED -#include "SkDynamicAnnotations.h" -#include "SkThread.h" +#include "SkAtomics.h" #include "SkInstCnt.h" #include "SkTemplates.h" @@ -51,22 +50,20 @@ public: * Ensures that all previous owner's actions are complete. */ bool unique() const { - // We believe we're reading fRefCnt in a safe way here, so we stifle the TSAN warning about - // an unproctected read. Generally, don't read fRefCnt, and don't stifle this warning. - bool const unique = (1 == sk_acquire_load(&fRefCnt)); - if (unique) { - // Acquire barrier (L/SL), if not provided by load of fRefCnt. - // Prevents user's 'unique' code from happening before decrements. - //TODO: issue the barrier only when unique is true + if (1 == sk_atomic_load(&fRefCnt, sk_memory_order_acquire)) { + // The acquire barrier is only really needed if we return true. It + // prevents code conditioned on the result of unique() from running + // until previous owners are all totally done calling unref(). + return true; } - return unique; + return false; } /** Increment the reference count. Must be balanced by a call to unref(). */ void ref() const { SkASSERT(fRefCnt > 0); - sk_atomic_inc(&fRefCnt); // No barrier required. + (void)sk_atomic_fetch_add(&fRefCnt, +1, sk_memory_order_relaxed); // No barrier required. } /** Decrement the reference count. If the reference count is 1 before the @@ -75,12 +72,11 @@ public: */ void unref() const { SkASSERT(fRefCnt > 0); - // Release barrier (SL/S), if not provided below. - if (sk_atomic_dec(&fRefCnt) == 1) { - // Acquire barrier (L/SL), if not provided above. - // Prevents code in dispose from happening before the decrement. - sk_membar_acquire__after_atomic_dec(); - internal_dispose(); + // A release here acts in place of all releases we "should" have been doing in ref(). + if (1 == sk_atomic_fetch_add(&fRefCnt, -1, sk_memory_order_acq_rel)) { + // Like unique(), the acquire is only needed on success, to make sure + // code in internal_dispose() doesn't happen before the decrement. + this->internal_dispose(); } } @@ -262,17 +258,15 @@ public: // - ref() doesn't need any barrier; // - unref() needs a release barrier, and an acquire if it's going to call delete. - bool unique() const { return 1 == sk_acquire_load(&fRefCnt); } - void ref() const { sk_atomic_inc(&fRefCnt); } + bool unique() const { return 1 == sk_atomic_load(&fRefCnt, sk_memory_order_acquire); } + void ref() const { (void)sk_atomic_fetch_add(&fRefCnt, +1, sk_memory_order_relaxed); } void unref() const { - int32_t prevValue = sk_atomic_dec(&fRefCnt); - SkASSERT(prevValue >= 1); - if (1 == prevValue) { + if (1 == sk_atomic_fetch_add(&fRefCnt, -1, sk_memory_order_acq_rel)) { SkDEBUGCODE(fRefCnt = 1;) // restore the 1 for our destructor's assert SkDELETE((const Derived*)this); } } - void deref() const { this->unref(); } // Chrome prefers to call deref(). + void deref() const { this->unref(); } private: mutable int32_t fRefCnt; diff --git a/include/effects/SkColorCubeFilter.h b/include/effects/SkColorCubeFilter.h index 65df345b07..1d4d0fd17d 100644 --- a/include/effects/SkColorCubeFilter.h +++ b/include/effects/SkColorCubeFilter.h @@ -10,6 +10,7 @@ #include "SkColorFilter.h" #include "SkData.h" +#include "SkMutex.h" class SK_API SkColorCubeFilter : public SkColorFilter { public: |