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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 |