mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-12-16 11:22:12 +00:00
b79ead9c84
* Replicate poco into base/poco/ * De-register poco submodule * Build poco from ClickHouse * Exclude poco from stylecheck * Exclude poco from whitespace check * Exclude poco from typo check * Remove x bit from sources/headers (the style check complained) * Exclude poco from duplicate include check * Fix fasttest * Remove contrib/poco-cmake/* * Simplify poco build descriptions * Remove poco stuff not used by ClickHouse * Glob poco sources * Exclude poco from clang-tidy
74 lines
2.2 KiB
C++
74 lines
2.2 KiB
C++
//
|
|
// 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
|