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/* Copyright (c) 2009, 2010, 2011, 2017 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef OVSDB_LOG_H
#define OVSDB_LOG_H 1
/* OVSDB log.
*
* A log consists of a series of records. After opening or creating a log with
* ovsdb_log_open(), the client may use ovsdb_log_read() to read any existing
* records, one by one. The client may also use ovsdb_log_write() to write new
* records (if some records have not yet been read at this point, then the
* first write truncates them).
*
* Log writes are atomic. A client may use ovsdb_log_commit() to ensure that
* they are durable.
*
* Logs provide a mechansim to allow the client to tell when they have grown
* enough that compacting may be warranted. After reading existing log
* contents, the client uses ovsdb_log_mark_base() to mark the "base" to be
* considered as the initial size of the log. Thereafter, a client may call
* ovsdb_log_grew_lots() to get an indication whether the log has grown enough
* that compacting is advised.
*/
#include <stdint.h>
#include <sys/types.h>
#include "compiler.h"
struct ds;
struct json;
struct ovsdb_log;
/* Access mode for opening an OVSDB log. */
enum ovsdb_log_open_mode {
OVSDB_LOG_READ_ONLY, /* Open existing file, read-only. */
OVSDB_LOG_READ_WRITE, /* Open existing file, read/write. */
OVSDB_LOG_CREATE_EXCL, /* Create new file, read/write. */
OVSDB_LOG_CREATE /* Create or open file, read/write. */
};
/* 'magic' for use with ovsdb_log_open() for OVSDB databases (see ovsdb(5)). */
#define OVSDB_MAGIC "JSON"
struct ovsdb_error *ovsdb_log_open(const char *name, const char *magic,
enum ovsdb_log_open_mode,
int locking, struct ovsdb_log **)
OVS_WARN_UNUSED_RESULT;
void ovsdb_log_close(struct ovsdb_log *);
const char *ovsdb_log_get_magic(const struct ovsdb_log *);
struct ovsdb_error *ovsdb_log_read(struct ovsdb_log *, struct json **)
OVS_WARN_UNUSED_RESULT;
void ovsdb_log_unread(struct ovsdb_log *);
struct ovsdb_error *ovsdb_log_reset(struct ovsdb_log *)
OVS_WARN_UNUSED_RESULT;
void ovsdb_log_compose_record(const struct json *, const char *magic,
struct ds *header, struct ds *data);
struct ovsdb_error *ovsdb_log_write(struct ovsdb_log *, const struct json *)
OVS_WARN_UNUSED_RESULT;
struct ovsdb_error *ovsdb_log_write_and_free(struct ovsdb_log *, struct json *)
OVS_WARN_UNUSED_RESULT;
uint64_t ovsdb_log_commit_start(struct ovsdb_log *);
uint64_t ovsdb_log_commit_progress(struct ovsdb_log *);
void ovsdb_log_commit_wait(struct ovsdb_log *, uint64_t);
struct ovsdb_error *ovsdb_log_commit_block(struct ovsdb_log *)
OVS_WARN_UNUSED_RESULT;
void ovsdb_log_mark_base(struct ovsdb_log *);
bool ovsdb_log_grew_lots(const struct ovsdb_log *);
struct ovsdb_error *ovsdb_log_replace(struct ovsdb_log *,
struct json **entries, size_t n)
OVS_WARN_UNUSED_RESULT;
struct ovsdb_error *ovsdb_log_replace_start(struct ovsdb_log *old,
struct ovsdb_log **newp)
OVS_WARN_UNUSED_RESULT;
struct ovsdb_error *ovsdb_log_replace_commit(struct ovsdb_log *old,
struct ovsdb_log *new)
OVS_WARN_UNUSED_RESULT;
void ovsdb_log_replace_abort(struct ovsdb_log *new);
/* For testing. */
void ovsdb_log_disable_renaming_open_files(void);
#endif /* ovsdb/log.h */
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