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author | Devtools Arcadia <arcadia-devtools@yandex-team.ru> | 2022-02-07 18:08:42 +0300 |
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committer | Devtools Arcadia <arcadia-devtools@mous.vla.yp-c.yandex.net> | 2022-02-07 18:08:42 +0300 |
commit | 1110808a9d39d4b808aef724c861a2e1a38d2a69 (patch) | |
tree | e26c9fed0de5d9873cce7e00bc214573dc2195b7 /contrib/libs/poco/Foundation/include/Poco/UniqueAccessExpireCache.h | |
download | ydb-1110808a9d39d4b808aef724c861a2e1a38d2a69.tar.gz |
intermediate changes
ref:cde9a383711a11544ce7e107a78147fb96cc4029
Diffstat (limited to 'contrib/libs/poco/Foundation/include/Poco/UniqueAccessExpireCache.h')
-rw-r--r-- | contrib/libs/poco/Foundation/include/Poco/UniqueAccessExpireCache.h | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/contrib/libs/poco/Foundation/include/Poco/UniqueAccessExpireCache.h b/contrib/libs/poco/Foundation/include/Poco/UniqueAccessExpireCache.h new file mode 100644 index 0000000000..a2d58f6433 --- /dev/null +++ b/contrib/libs/poco/Foundation/include/Poco/UniqueAccessExpireCache.h @@ -0,0 +1,73 @@ +// +// UniqueAccessExpireCache.h +// +// Library: Foundation +// Package: Cache +// Module: UniqueAccessExpireCache +// +// Definition of the UniqueAccessExpireCache class. +// +// Copyright (c) 2006, Applied Informatics Software Engineering GmbH. +// and Contributors. +// +// SPDX-License-Identifier: BSL-1.0 +// + + +#ifndef Foundation_UniqueAccessExpireCache_INCLUDED +#define Foundation_UniqueAccessExpireCache_INCLUDED + + +#include "Poco/AbstractCache.h" +#include "Poco/UniqueAccessExpireStrategy.h" + + +namespace Poco { + + +template < + class TKey, + class TValue, + class TMutex = FastMutex, + class TEventMutex = FastMutex +> +class UniqueAccessExpireCache: public AbstractCache<TKey, TValue, UniqueAccessExpireStrategy<TKey, TValue>, TMutex, TEventMutex> + /// An UniqueAccessExpireCache caches entries for a given time span. In contrast + /// to ExpireCache which only allows to set a per cache expiration value, it allows to define + /// expiration per CacheEntry. + /// Each TValue object must thus offer the following method: + /// + /// const Poco::Timespan& getTimeout() const; + /// + /// which returns the relative timespan for how long the entry should be valid without being accessed! + /// The absolute expire timepoint is calculated as now() + getTimeout(). + /// Accessing an object will update this absolute expire timepoint. + /// You can use the Poco::AccessExpirationDecorator to add the getExpiration + /// method to values that do not have a getExpiration function. + /// + /// Be careful when using an UniqueAccessExpireCache. A cache is often used + /// like cache.has(x) followed by cache.get x). Note that it could happen + /// that the "has" call works, then the current execution thread gets descheduled, time passes, + /// the entry gets invalid, thus leading to an empty SharedPtr being returned + /// when "get" is invoked. +{ +public: + UniqueAccessExpireCache(): + AbstractCache<TKey, TValue, UniqueAccessExpireStrategy<TKey, TValue>, TMutex, TEventMutex>(UniqueAccessExpireStrategy<TKey, TValue>()) + { + } + + ~UniqueAccessExpireCache() + { + } + +private: + UniqueAccessExpireCache(const UniqueAccessExpireCache& aCache); + UniqueAccessExpireCache& operator = (const UniqueAccessExpireCache& aCache); +}; + + +} // namespace Poco + + +#endif // Foundation_UniqueAccessExpireCache_INCLUDED |