import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

intl/icu/source/common/sharedobject.cpp

@@ -0,0 +1,87 @@
+// Copyright (C) 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
+/*
+******************************************************************************
+* Copyright (C) 2015, International Business Machines
+* Corporation and others.  All Rights Reserved.
+******************************************************************************
+* sharedobject.cpp
+*/
+#include "sharedobject.h"
+#include "uassert.h"
+
+U_NAMESPACE_BEGIN
+
+SharedObject::~SharedObject() {}
+
+UnifiedCacheBase::~UnifiedCacheBase() {}
+
+void
+SharedObject::addRef(UBool fromWithinCache) const {
+    umtx_atomic_inc(&totalRefCount);
+
+    // Although items in use may not be correct immediately, it
+    // will be correct eventually.
+    if (umtx_atomic_inc(&hardRefCount) == 1 && cachePtr != NULL) {
+        // If this object is cached, and the hardRefCount goes from 0 to 1,
+        // then the increment must happen from within the cache while the
+        // cache global mutex is locked. In this way, we can be rest assured
+        // that data races can't happen if the cache performs some task if
+        // the hardRefCount is zero while the global cache mutex is locked.
+        (void)fromWithinCache;   // Suppress unused variable warning in non-debug builds.
+        U_ASSERT(fromWithinCache);
+        cachePtr->incrementItemsInUse();
+    }
+}
+
+void
+SharedObject::removeRef(UBool fromWithinCache) const {
+    UBool decrementItemsInUse = (umtx_atomic_dec(&hardRefCount) == 0);
+    UBool allReferencesGone = (umtx_atomic_dec(&totalRefCount) == 0);
+
+    // Although items in use may not be correct immediately, it
+    // will be correct eventually.
+    if (decrementItemsInUse && cachePtr != NULL) {
+        if (fromWithinCache) {
+            cachePtr->decrementItemsInUse();
+        } else {
+            cachePtr->decrementItemsInUseWithLockingAndEviction();
+        }
+    }
+    if (allReferencesGone) {
+        delete this;
+    }
+}
+
+void
+SharedObject::addSoftRef() const {
+    umtx_atomic_inc(&totalRefCount);
+    ++softRefCount;
+}
+
+void
+SharedObject::removeSoftRef() const {
+    --softRefCount;
+    if (umtx_atomic_dec(&totalRefCount) == 0) {
+        delete this;
+    }
+}
+
+int32_t
+SharedObject::getRefCount() const {
+    return umtx_loadAcquire(totalRefCount);
+}
+
+int32_t
+SharedObject::getHardRefCount() const {
+    return umtx_loadAcquire(hardRefCount);
+}
+
+void
+SharedObject::deleteIfZeroRefCount() const {
+    if(getRefCount() == 0) {
+        delete this;
+    }
+}
+
+U_NAMESPACE_END