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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*/
/** BEGIN COPYRIGHT BLOCK
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301 USA
*
* Copyright (C) 2007 Red Hat, Inc.
* All rights reserved.
* END COPYRIGHT BLOCK **/
#ifndef _CACHE_H_
#define _CACHE_H_
#ifdef HAVE_CONFIG_H
#ifndef AUTOTOOLS_CONFIG_H
#define AUTOTOOLS_CONFIG_H
/* Eliminate warnings when using Autotools */
#undef PACKAGE_BUGREPORT
#undef PACKAGE_NAME
#undef PACKAGE_STRING
#undef PACKAGE_TARNAME
#undef PACKAGE_VERSION
#include <config.h>
#endif /* AUTOTOOLS_CONFIG_H */
#endif /* HAVE_CONFIG_H */
#include "httpClient/httpc/Iterator.h"
/**
* Simple cache implementation
*/
/**
* Contains a cache entry and housekeeping info
*/
class CacheEntry {
public:
/**
* Constructor
*
* @param key Pointer to the key being cached
* @param data Pointer to the data being cached
*/
CacheEntry( const char *key, void *data );
/**
* Destructor
*/
virtual ~CacheEntry();
/**
* Returns a pointer to the cached key
*
* @return A pointer to the cached key
*/
const char *GetKey();
/**
* Returns a pointer to the cached data
*
* @return A pointer to the cached data
*/
void *GetData();
/**
* Returns the time when the entry was created
*
* @return The time when the entry was created
*/
long GetStartTime();
private:
char *m_key;
void *m_data;
time_t m_startTime;
};
/**
* Contains a generic cache; this is currently an abstract base class
*/
class Cache {
protected:
/**
* Default constructor
*/
Cache();
public:
/**
* Constructor
*
* @param name of the cache
* @param ttl Time to live of each cache entry
* @param implicitLock true if the Cached is to do locking internally
* when required; false if the caller will take responsibility
*/
Cache( const char *name, int ttl, bool implictLock = false );
/**
* Destructor
*/
virtual ~Cache();
/**
* Returns the number of entries in the cache
*
* @return The number of entries in the cache
*/
virtual int GetCount();
/**
* Acquires a read lock on the cache. Multiple threads may simultaneously
* have a read lock, but attempts to acquire a read lock will block
* if another thread already has a write lock. It is illegal to request
* a read lock if the thread already has one.
*/
void ReadLock();
/**
* Acquires a write lock on the cache. Only one thread may have a write
* lock at any given time; attempts to acquire a write lock will block
* if another thread already has one. It is illegal to request
* a write lock if the thread already has one.
*/
void WriteLock();
/**
* Releases a read or write lock that the thread has on the cache
*/
void Unlock();
protected:
/**
* Initializes the object - to be called from the constructor
*
* @param name of the cache
* @param ttl Time to live of each cache entry
* @param implicitLock true if the Cached is to do locking internally
* when required; false if the caller will take responsibility
*/
void Initialize( const char *name, int ttl, bool implictLock );
protected:
const char *m_name;
int m_ttl;
PLHashTable* m_cache;
PRRWLock* m_cacheLock;
bool m_implicitLock;
};
/**
* Contains a cache where the keys are strings
*/
class StringKeyCache : public Cache {
public:
/**
* Constructor
*
* @param name of the cache
* @param ttl Time to live of each cache entry
* @param implicitLock true if the Cached is to do locking internally
* when required; false if the caller will take responsibility
*/
StringKeyCache( const char *name, int ttl, bool implictLock = false );
/**
* Destructor
*/
virtual ~StringKeyCache();
/**
* Returns a cache entry
*
* @param key The name of the cache entry
* @return The corresponding cache entry, or NULL if not found
*/
CacheEntry *Get( const char *key );
/**
* Adds a cache entry
*
* @param key The name of the cache entry; an internal copy is made
* @param value The value of the cache entry
* @return The corresponding cache entry, or NULL if it couldn't be added
*/
CacheEntry *Put( const char *key, void *value );
/**
* Removes a cache entry; does not free the entry object
*
* @param key The name of the cache entry
* @return The corresponding cache entry, or NULL if not found
*/
CacheEntry *Remove( const char *key );
/**
* Allocates and returns a list of keys in the cache
*
* @param keys Returns an array of names; each name and also the
* array itself are to be freed by the caller with delete
* @return The number of keys found
*/
int GetKeys( char ***keys );
/**
* Returns an iterator over keys in the cache
*
* @return An iterator over keys in the cache
*/
Iterator *GetKeyIterator();
};
#endif // _CACHE_H_
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