icuSources/common/sharedobject.cpp

   1 // © 2016 and later: Unicode, Inc. and others.
   2 // License & terms of use: http://www.unicode.org/copyright.html
   3 /*
   4 ******************************************************************************
   5 * Copyright (C) 2015, International Business Machines
   6 * Corporation and others.  All Rights Reserved.
   7 ******************************************************************************
   8 * sharedobject.cpp
   9 */
  10 #include "sharedobject.h"
  11 #include "uassert.h"
  12
  13 U_NAMESPACE_BEGIN
  14
  15 SharedObject::~SharedObject() {}
  16
  17 UnifiedCacheBase::~UnifiedCacheBase() {}
  18
  19 void
  20 SharedObject::addRef(UBool fromWithinCache) const {
  21     umtx_atomic_inc(&totalRefCount);
  22
  23     // Although items in use may not be correct immediately, it
  24     // will be correct eventually.
  25     if (umtx_atomic_inc(&hardRefCount) == 1 && cachePtr != NULL) {
  26         // If this object is cached, and the hardRefCount goes from 0 to 1,
  27         // then the increment must happen from within the cache while the
  28         // cache global mutex is locked. In this way, we can be rest assured
  29         // that data races can't happen if the cache performs some task if
  30         // the hardRefCount is zero while the global cache mutex is locked.
  31         (void)fromWithinCache;   // Suppress unused variable warning in non-debug builds.
  32         U_ASSERT(fromWithinCache);
  33         cachePtr->incrementItemsInUse();
  34     }
  35 }
  36
  37 void
  38 SharedObject::removeRef(UBool fromWithinCache) const {
  39     UBool decrementItemsInUse = (umtx_atomic_dec(&hardRefCount) == 0);
  40     UBool allReferencesGone = (umtx_atomic_dec(&totalRefCount) == 0);
  41
  42     // Although items in use may not be correct immediately, it
  43     // will be correct eventually.
  44     if (decrementItemsInUse && cachePtr != NULL) {
  45         if (fromWithinCache) {
  46             cachePtr->decrementItemsInUse();
  47         } else {
  48             cachePtr->decrementItemsInUseWithLockingAndEviction();
  49         }
  50     }
  51     if (allReferencesGone) {
  52         delete this;
  53     }
  54 }
  55
  56 void
  57 SharedObject::addSoftRef() const {
  58     umtx_atomic_inc(&totalRefCount);
  59     ++softRefCount;
  60 }
  61
  62 void
  63 SharedObject::removeSoftRef() const {
  64     --softRefCount;
  65     if (umtx_atomic_dec(&totalRefCount) == 0) {
  66         delete this;
  67     }
  68 }
  69
  70 int32_t
  71 SharedObject::getRefCount() const {
  72     return umtx_loadAcquire(totalRefCount);
  73 }
  74
  75 int32_t
  76 SharedObject::getHardRefCount() const {
  77     return umtx_loadAcquire(hardRefCount);
  78 }
  79
  80 void
  81 SharedObject::deleteIfZeroRefCount() const {
  82     if(getRefCount() == 0) {
  83         delete this;
  84     }
  85 }
  86
  87 U_NAMESPACE_END