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construct/include/ircd/db/cache.h
2018-09-05 03:13:05 -07:00

76 lines
2.8 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.
#pragma once
#define HAVE_IRCD_DB_CACHE_H
// Interface to a cache. This interface is included in the standard include
// stack by forward declaring the rocksdb::Cache symbol.
//
// The interface overloads on a pointer to a cache for developer convenience.
// This is because caches may not always exist for some entity, and accessors
// will return a null pointer. The pointer overloads here will safely accept
// null pointers and provide the appropriate no-op behavior.
namespace ircd::db
{
struct cache_stats;
// Get our stats
const cache_stats &stats(const rocksdb::Cache &);
cache_stats stats(const rocksdb::Cache *const &);
// Get capacity
size_t capacity(const rocksdb::Cache &);
size_t capacity(const rocksdb::Cache *const &);
// Set capacity
void capacity(rocksdb::Cache &, const size_t &);
bool capacity(rocksdb::Cache *const &, const size_t &);
// Get usage
size_t usage(const rocksdb::Cache &);
size_t usage(const rocksdb::Cache *const &);
// Test if key exists
bool exists(const rocksdb::Cache &, const string_view &key);
bool exists(const rocksdb::Cache *const &, const string_view &key);
// Iterate the cache entries.
using cache_closure = std::function<void (const const_buffer &)>;
void for_each(const rocksdb::Cache &, const cache_closure &);
void for_each(const rocksdb::Cache *const &, const cache_closure &);
// Manually cache a key/value directly
bool insert(rocksdb::Cache &, const string_view &key, unique_buffer<const_buffer>);
bool insert(rocksdb::Cache *const &, const string_view &key, unique_buffer<const_buffer>);
// Manually cache a copy of key/value
bool insert(rocksdb::Cache &, const string_view &key, const string_view &value);
bool insert(rocksdb::Cache *const &, const string_view &key, const string_view &value);
// Remove key if it exists
bool remove(rocksdb::Cache &, const string_view &key);
bool remove(rocksdb::Cache *const &, const string_view &key);
// Clear the cache (won't clear entries which are actively referenced)
void clear(rocksdb::Cache &);
void clear(rocksdb::Cache *const &);
}
/// Our custom cache statistics. Though the rocksdb::Statistics ticker could
/// be instantiated for each cache we have our own counters, and we let the
/// rocksdb cache impl update our database ticker instead for aggregate stats.
struct ircd::db::cache_stats
{
size_t inserts {0};
size_t misses {0};
size_t hits {0};
};