icuSources/common/sharedobject.cpp

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