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// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef NET_SSL_SSL_CLIENT_SESSION_CACHE_H
#define NET_SSL_SSL_CLIENT_SESSION_CACHE_H
#include <openssl/ssl.h>
#include <stddef.h>
#include <memory>
#include <string>
#include "base/bind.h"
#include "base/containers/mru_cache.h"
#include "base/macros.h"
#include "base/memory/memory_pressure_monitor.h"
#include "base/synchronization/lock.h"
#include "base/threading/thread_checker.h"
#include "base/time/time.h"
#include "net/base/net_export.h"
#include "net/ssl/scoped_openssl_types.h"
namespace base {
class Clock;
}
namespace net {
class NET_EXPORT SSLClientSessionCache {
public:
struct Config {
// The maximum number of entries in the cache.
size_t max_entries = 1024;
// The number of calls to Lookup before a new check for expired sessions.
size_t expiration_check_count = 256;
// How long each session should last.
base::TimeDelta timeout = base::TimeDelta::FromHours(1);
};
explicit SSLClientSessionCache(const Config& config);
~SSLClientSessionCache();
size_t size() const;
// Returns the session associated with |cache_key| and moves it to the front
// of the MRU list. Returns nullptr if there is none.
ScopedSSL_SESSION Lookup(const std::string& cache_key);
// Inserts |session| into the cache at |cache_key|. If there is an existing
// one, it is released. Every |expiration_check_count| calls, the cache is
// checked for stale entries.
void Insert(const std::string& cache_key, SSL_SESSION* session);
// Removes all entries from the cache.
void Flush();
void SetClockForTesting(std::unique_ptr<base::Clock> clock);
private:
struct CacheEntry {
CacheEntry();
~CacheEntry();
ScopedSSL_SESSION session;
// The time at which this entry was created.
base::Time creation_time;
};
using CacheEntryMap =
base::HashingMRUCache<std::string, std::unique_ptr<CacheEntry>>;
// Returns true if |entry| is expired as of |now|.
bool IsExpired(CacheEntry* entry, const base::Time& now);
// Removes all expired sessions from the cache.
void FlushExpiredSessions();
// Clear cache on low memory notifications callback.
void OnMemoryPressure(
base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level);
std::unique_ptr<base::Clock> clock_;
Config config_;
CacheEntryMap cache_;
size_t lookups_since_flush_;
// TODO(davidben): After https://crbug.com/458365 is fixed, replace this with
// a ThreadChecker. The session cache should be single-threaded like other
// classes in net.
base::Lock lock_;
std::unique_ptr<base::MemoryPressureListener> memory_pressure_listener_;
DISALLOW_COPY_AND_ASSIGN(SSLClientSessionCache);
};
} // namespace net
#endif // NET_SSL_SSL_CLIENT_SESSION_CACHE_H