SkAtomic: always use std::atomic

include/private/SkAtomics.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkAtomics_DEFINED
 #define SkAtomics_DEFINED
 
 // This file is not part of the public Skia API.
 #include "SkTypes.h"
+#include <atomic>
+
+// ~~~~~~~~ APIs ~~~~~~~~~
 
 enum sk_memory_order {
     sk_memory_order_relaxed,
     sk_memory_order_consume,
     sk_memory_order_acquire,
     sk_memory_order_release,
     sk_memory_order_acq_rel,
     sk_memory_order_seq_cst,
 };
 
@@ skipping 56 matching lines @@
 
     bool compare_exchange(T* expected, const T& desired,
                           sk_memory_order success = default_memory_order,
                           sk_memory_order failure = default_memory_order) {
         return sk_atomic_compare_exchange(&fVal, expected, desired, success, failure);
     }
 private:
     T fVal;
 };
 
-// IWYU pragma: begin_exports
-#if defined(_MSC_VER)
-    #include "../ports/SkAtomics_std.h"
-#elif !defined(SK_BUILD_FOR_IOS) && defined(__ATOMIC_RELAXED)
-    #include "../ports/SkAtomics_atomic.h"
-#else
-    #include "../ports/SkAtomics_sync.h"
-#endif
-// IWYU pragma: end_exports
+// ~~~~~~~~ Implementations ~~~~~~~~~
+
+template <typename T>
+T sk_atomic_load(const T* ptr, sk_memory_order mo) {
+    SkASSERT(mo == sk_memory_order_relaxed ||
+             mo == sk_memory_order_seq_cst ||
+             mo == sk_memory_order_acquire ||
+             mo == sk_memory_order_consume);
+    const std::atomic<T>* ap = reinterpret_cast<const std::atomic<T>*>(ptr);
+    return std::atomic_load_explicit(ap, (std::memory_order)mo);
+}
+
+template <typename T>
+void sk_atomic_store(T* ptr, T val, sk_memory_order mo) {
+    SkASSERT(mo == sk_memory_order_relaxed ||
+             mo == sk_memory_order_seq_cst ||
+             mo == sk_memory_order_release);
+    std::atomic<T>* ap = reinterpret_cast<std::atomic<T>*>(ptr);
+    return std::atomic_store_explicit(ap, val, (std::memory_order)mo);
+}
+
+template <typename T>
+T sk_atomic_fetch_add(T* ptr, T val, sk_memory_order mo) {
+    // All values of mo are valid.
+    std::atomic<T>* ap = reinterpret_cast<std::atomic<T>*>(ptr);
+    return std::atomic_fetch_add_explicit(ap, val, (std::memory_order)mo);
+}
+
+template <typename T>
+T sk_atomic_fetch_sub(T* ptr, T val, sk_memory_order mo) {
+    // All values of mo are valid.
+    std::atomic<T>* ap = reinterpret_cast<std::atomic<T>*>(ptr);
+    return std::atomic_fetch_sub_explicit(ap, val, (std::memory_order)mo);
+}
+
+template <typename T>
+bool sk_atomic_compare_exchange(T* ptr, T* expected, T desired,
+                                sk_memory_order success,
+                                sk_memory_order failure) {
+    // All values of success are valid.
+    SkASSERT(failure == sk_memory_order_relaxed ||
+             failure == sk_memory_order_seq_cst ||
+             failure == sk_memory_order_acquire ||
+             failure == sk_memory_order_consume);
+    SkASSERT(failure <= success);
+    std::atomic<T>* ap = reinterpret_cast<std::atomic<T>*>(ptr);
+    return std::atomic_compare_exchange_strong_explicit(ap, expected, desired,
+                                                        (std::memory_order)success,
+                                                        (std::memory_order)failure);
+}
+
+template <typename T>
+T sk_atomic_exchange(T* ptr, T val, sk_memory_order mo) {
+    // All values of mo are valid.
+    std::atomic<T>* ap = reinterpret_cast<std::atomic<T>*>(ptr);
+    return std::atomic_exchange_explicit(ap, val, (std::memory_order)mo);
+}
+
+// ~~~~~~~~ Legacy APIs ~~~~~~~~~
 
 // From here down we have shims for our old atomics API, to be weaned off of.
 // We use the default sequentially-consistent memory order to make things simple
 // and to match the practical reality of our old _sync and _win implementations.
 
 inline int32_t sk_atomic_inc(int32_t* ptr)            { return sk_atomic_fetch_add(ptr, +1); }
 inline int32_t sk_atomic_dec(int32_t* ptr)            { return sk_atomic_fetch_add(ptr, -1); }
 inline int32_t sk_atomic_add(int32_t* ptr, int32_t v) { return sk_atomic_fetch_add(ptr,  v); }
 
 inline int64_t sk_atomic_inc(int64_t* ptr) { return sk_atomic_fetch_add<int64_t>(ptr, +1); }
@@ skipping 20 matching lines @@
 template <typename T>
 T sk_acquire_load(T* ptr) { return sk_atomic_load(ptr, sk_memory_order_acquire); }
 
 template <typename T>
 void sk_release_store(T* ptr, T val) { sk_atomic_store(ptr, val, sk_memory_order_release); }
 
 inline void sk_membar_acquire__after_atomic_dec() {}
 inline void sk_membar_acquire__after_atomic_conditional_inc() {}
 
 #endif//SkAtomics_DEFINED