libvirt/src/util/virfilecache.h
Pavel Hrdina ac3eb2ab24 util: introduce virFileCache
The new virFileCache will nicely handle the caching logic for any data
that we would like to cache.  For each type of data we will just need
to implement few handlers that will take care of creating, validating,
loading and saving the cached data.

The cached data must be an instance of virObject.

Currently we cache QEMU capabilities which will start using
virFileCache.

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
2017-07-26 15:31:25 +02:00

138 lines
3.7 KiB
C

/*
* virfilecache.h: file caching for data
*
* Copyright (C) 2017 Red Hat, Inc.
*
* 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; either
* version 2.1 of the License, or (at your option) any later version.
*
* 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, see
* <http://www.gnu.org/licenses/>.
*
*/
#ifndef __VIR_FILE_CACHE_H__
# define __VIR_FILE_CACHE_H__
# include "internal.h"
# include "virobject.h"
# include "virhash.h"
typedef struct _virFileCache virFileCache;
typedef virFileCache *virFileCachePtr;
/**
* virFileCacheIsValidPtr:
* @data: data object to validate
* @priv: private data created together with cache
*
* Validates the cached data whether it needs to be refreshed
* or no.
*
* Returns *true* if it's valid or *false* if not valid.
*/
typedef bool
(*virFileCacheIsValidPtr)(void *data,
void *priv);
/**
* virFileCacheNewDataPtr:
* @name: name of the new data
* @priv: private data created together with cache
*
* Creates a new data based on the @name. The returned data must be
* an instance of virObject.
*
* Returns data object or NULL on error.
*/
typedef void *
(*virFileCacheNewDataPtr)(const char *name,
void *priv);
/**
* virFileCacheLoadFilePtr:
* @filename: name of a file with cached data
* @name: name of the cached data
* @priv: private data created together with cache
*
* Loads the cached data from a file @filename.
*
* Returns cached data object or NULL on error.
*/
typedef void *
(*virFileCacheLoadFilePtr)(const char *filename,
const char *name,
void *priv);
/**
* virFileCacheSaveFilePtr:
* @data: data object to save into a file
* @filename: name of the file where to store the cached data
* @priv: private data created together with cache
*
* Stores the cached to a file @filename.
*
* Returns 0 on success, -1 on error.
*/
typedef int
(*virFileCacheSaveFilePtr)(void *data,
const char *filename,
void *priv);
/**
* virFileCachePrivFreePtr:
* @priv: private data created together with cache
*
* This is used to free the private data when the cache object
* is removed.
*/
typedef void
(*virFileCachePrivFreePtr)(void *priv);
typedef struct _virFileCacheHandlers virFileCacheHandlers;
typedef virFileCacheHandlers *virFileCacheHandlersPtr;
struct _virFileCacheHandlers {
virFileCacheIsValidPtr isValid;
virFileCacheNewDataPtr newData;
virFileCacheLoadFilePtr loadFile;
virFileCacheSaveFilePtr saveFile;
virFileCachePrivFreePtr privFree;
};
virFileCachePtr
virFileCacheNew(const char *dir,
const char *suffix,
virFileCacheHandlers *handlers);
void *
virFileCacheLookup(virFileCachePtr cache,
const char *name);
void *
virFileCacheLookupByFunc(virFileCachePtr cache,
virHashSearcher iter,
const void *iterData);
void *
virFileCacheGetPriv(virFileCachePtr cache);
void
virFileCacheSetPriv(virFileCachePtr cache,
void *priv);
int
virFileCacheInsertData(virFileCachePtr cache,
const char *name,
void *data);
#endif /* __VIR_FILE_CACHE_H__ */