netsurf/content/backing_store.h

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/*
* Copyright 2014 Vincent Sanders <vince@netsurf-browser.org>
*
* This file is part of NetSurf, http://www.netsurf-browser.org/
*
* NetSurf is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* NetSurf 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* \file
* Low-level source data cache backing store interface.
*/
#ifndef NETSURF_CONTENT_LLCACHE_PRIVATE_H_
#define NETSURF_CONTENT_LLCACHE_PRIVATE_H_
#include "content/llcache.h"
/** storage control flags */
enum backing_store_flags {
/** no special processing */
BACKING_STORE_NONE = 0,
/** data is metadata */
BACKING_STORE_META = 1,
};
/**
* low level cache backing store operation table
*
* The low level cache (source objects) has the capability to make
* objects and their metadata (headers etc) persistant by writing to a
* backing store using these operations.
*/
struct gui_llcache_table {
/**
* Initialise the backing store.
*
* @param parameters to configure backing store.
* @return NSERROR_OK on success or error code on faliure.
*/
nserror (*initialise)(const struct llcache_store_parameters *parameters);
/**
* Finalise the backing store.
*
* @return NSERROR_OK on success or error code on faliure.
*/
nserror (*finalise)(void);
/**
* Place an object in the backing store.
*
* The object is placed in the persistent store and may be
* retrieved with the fetch method.
*
* The backing store will take a reference to the
* passed data, subsequently the caller should explicitly
* release the allocation using the release method and not
* free the data itself.
*
* The caller may not assume that the persistent storage has
* been completely written on return.
*
* @param[in] url The url is used as the unique primary key for the data.
* @param[in] flags The flags to control how the obejct is stored.
* @param[in] data The objects data.
* @param[in] datalen The length of the \a data.
* @return NSERROR_OK on success or error code on faliure.
*/
nserror (*store)(struct nsurl *url, enum backing_store_flags flags,
uint8_t *data, const size_t datalen);
/**
* Retrive an object from the backing store.
*
* The caller may provide a buffer in \a data and a buffer
* length in \a datalen. Alternatively the backing store will
* allocate its own buffer if \a data is NULL, this memory is
* managed by the backing store.
*
* The caller must assume nothing about the backing store
* allocated buffers and the storage and *must* be freed by
* calling the release method.
*
* @param[in] url The url is used as the unique primary key for the data.
* @param[in] flags The flags to control how the object is retrived.
* @param[in,out] data The retrived objects data.
* @param[in,out] datalen The length of the \a data retrieved.
* @return NSERROR_OK on success or error code on faliure.
*/
nserror (*fetch)(struct nsurl *url, enum backing_store_flags flags,
uint8_t **data, size_t *datalen);
/**
* release a previously fetched or stored memory object.
*
* @param url The url is used as the unique primary key to invalidate.
* @param[in] flags The flags to control how the object data is released.
* @return NSERROR_OK on success or error code on faliure.
*/
nserror (*release)(struct nsurl *url, enum backing_store_flags flags);
/**
* Invalidate a source object from the backing store.
*
* The entry (if present in the backing store) must no longer
* be returned as a result to the fetch or meta operations.
*
* If the entry had data allocated it will be released.
*
* @param url The url is used as the unique primary key to invalidate.
* @return NSERROR_OK on success or error code on faliure.
*/
nserror (*invalidate)(struct nsurl *url);
};
extern struct gui_llcache_table* null_llcache_table;
extern struct gui_llcache_table* filesystem_llcache_table;
#endif