Fix deprecated atomic APIs used in AtomicReference (#27)

Author: neakor

Sources/Concurrency/AtomicReference.swift

@@ -16,6 +16,7 @@
 
 import Foundation
 import libkern
+import ObjCBridges
 
 /// A concurrency utility class that supports locking-free synchronization on mutating an object
 /// reference. Unlike using a lock, concurrent read and write accesses to this class is allowed. At
@@ -28,7 +29,7 @@ public class AtomicReference<ValueType> {
         get {
             // Create a memory barrier to ensure the entire memory stack is in sync so we
             // can safely retrieve the value. This guarantees the initial value is in sync.
-            OSMemoryBarrier()
+            atomic_thread_fence(memory_order_seq_cst)
             return wrappedValue
         }
         set {
@@ -59,7 +60,7 @@ public class AtomicReference<ValueType> {
         let expectPointer = unsafePassUnretainedPointer(value: expect)
         let newValuePointer = unsafePassUnretainedPointer(value: newValue)
 
-        if OSAtomicCompareAndSwapPtrBarrier(expectPointer, newValuePointer, pointer) {
+        if AtomicBridges.comparePointer(pointer, withExpectedPointer: expectPointer, andSwapPointer: newValuePointer) {
             // If pointer swap succeeded, a memory berrier is created, so we can safely write the new
             // value.
             wrappedValue = newValue

Sources/ObjCBridges/AtomicBridges.m

@@ -30,4 +30,8 @@ + (bool)compare:(_Atomic(long) *)value withExpected:(long *)expected andSwap:(lo
     return atomic_compare_exchange_strong(value, expected, desired);
 }
 
++ (bool)comparePointer:(void * volatile *)value withExpectedPointer:(void *)expected andSwapPointer:(void *)desired {
+    return __sync_bool_compare_and_swap(value, expected, desired);
+}
+
 @end

Sources/ObjCBridges/include/AtomicBridges.h

@@ -27,6 +27,8 @@ NS_ASSUME_NONNULL_BEGIN
 
 + (bool)compare:(_Atomic(long) *)value withExpected:(long *)expected andSwap:(long)desired;
 
++ (bool)comparePointer:(void * _Nullable volatile * _Nonnull)value withExpectedPointer:(void *)expected andSwapPointer:(void *)desired;
+
 @end
 
 NS_ASSUME_NONNULL_END

Tests/ConcurrencyTests/AtomicIntTests.swift

@@ -19,18 +19,6 @@ import XCTest
 
 class AtomicIntTests: XCTestCase {
 
-    static var allTests = [
-        ("test_init_verifyInitialValue", test_init_verifyInitialValue),
-        ("test_initGetSet_verifySetToNewValue", test_initGetSet_verifySetToNewValue),
-        ("test_compareAndSet_verifySettingNewValue", test_compareAndSet_verifySettingNewValue),
-        ("test_compareAndSet_withFalseExpectValue_verifyNotSettingNewValue", test_compareAndSet_withFalseExpectValue_verifyNotSettingNewValue),
-        ("test_getAndSet_verifySettingNewValueReturningOldValue", test_getAndSet_verifySettingNewValueReturningOldValue),
-        ("test_incrementAndGet_verifyNewValue", test_incrementAndGet_verifyNewValue),
-        ("test_decrementAndGet_verifyNewValue", test_decrementAndGet_verifyNewValue),
-        ("test_getAndIncrement_verifyNewValue", test_getAndIncrement_verifyNewValue),
-        ("test_getAndDecrement_verifyNewValue", test_getAndDecrement_verifyNewValue),
-    ]
-
     func test_init_verifyInitialValue() {
         let initialValue = 123
         let atomicInt = AtomicInt(initialValue: initialValue)

Tests/ConcurrencyTests/AtomicReferenceTests.swift

@@ -19,16 +19,6 @@ import XCTest
 
 class AtomicReferenceTests: XCTestCase {
 
-    static var allTests = [
-        ("test_init_verifyInitialValue", test_init_verifyInitialValue),
-        ("test_initGetSet_verifySetToNewValue", test_initGetSet_verifySetToNewValue),
-        ("test_compareAndSet_verifySettingNewValue", test_compareAndSet_verifySettingNewValue),
-        ("test_compareAndSet_withFalseExpectValue_verifyNotSettingNewValue", test_compareAndSet_withFalseExpectValue_verifyNotSettingNewValue),
-        ("test_compareAndSet_withNil_verifySettingNewValue", test_compareAndSet_withNil_verifySettingNewValue),
-        ("test_getAndSet_verifySettingNewValueReturningOldValue", test_getAndSet_verifySettingNewValueReturningOldValue),
-        ("test_compareAndSet_initialNilThenResetToNil_verifySuccess", test_compareAndSet_initialNilThenResetToNil_verifySuccess),
-    ]
-
     func test_init_verifyInitialValue() {
         let initialValue = NSObject()
         let atomicRef = AtomicReference<NSObject>(initialValue: initialValue)

Tests/ConcurrencyTests/CountDownLatchTests.swift

@@ -19,14 +19,6 @@ import XCTest
 
 class CountDownLatchTests: XCTestCase {
 
-    static var allTests = [
-        ("test_countDown_await_verifyCompletionWithTrue", test_countDown_await_verifyCompletionWithTrue),
-        ("test_countDown_await_withTimeout_verifyCompletionWithFalse", test_countDown_await_withTimeout_verifyCompletionWithFalse),
-        ("test_countDown_await_verifyDuplicateCountDown_verifyDuplicateAwaitCompletesWithTrue", test_countDown_await_verifyDuplicateCountDown_verifyDuplicateAwaitCompletesWithTrue),
-        ("test_multipleAwaitBeforeCountDown_verifyCompletesWithTrue", test_multipleAwaitBeforeCountDown_verifyCompletesWithTrue),
-        ("test_multipleAsyncAwaitBeforeCountDown_verifyCompletesWithTrue", test_multipleAsyncAwaitBeforeCountDown_verifyCompletesWithTrue),
-    ]
-
     func test_countDown_await_verifyCompletionWithTrue() {
         let latch = CountDownLatch(count: 3)