/*
- * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
- * David Goulet <dgoulet@efficios.com>
+ * Copyright (C) 2013 Julien Desfossez <jdesfossez@efficios.com>
+ * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License, version 2 only,
- * as published by the Free Software Foundation.
+ * SPDX-License-Identifier: GPL-2.0-only
*
- * This program 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, write to the Free Software Foundation, Inc.,
- * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef CONSUMER_METADATA_CACHE_H
#define CONSUMER_METADATA_CACHE_H
#include <common/consumer/consumer.h>
+#include <common/dynamic-buffer.h>
-struct consumer_metadata_cache {
- char *data;
- uint64_t cache_alloc_size;
+enum consumer_metadata_cache_write_status {
+ CONSUMER_METADATA_CACHE_WRITE_STATUS_ERROR = -1,
+ /*
+ * New metadata content was appended to the cache successfully.
+ * Previously available content remains valid.
+ */
+ CONSUMER_METADATA_CACHE_WRITE_STATUS_APPENDED_CONTENT = 0,
+ /*
+ * The new content pushed to the cache invalidated the content that
+ * was already present. The contents of the cache should be re-read.
+ */
+ CONSUMER_METADATA_CACHE_WRITE_STATUS_INVALIDATED,
/*
- * Current version of the metadata cache.
+ * A metadata cache write can simply overwrite an already existing
+ * section of the cache (and it should be a write-through with identical
+ * data). From the caller's standpoint, there is no change to the state
+ * of the cache.
*/
+ CONSUMER_METADATA_CACHE_WRITE_STATUS_NO_CHANGE,
+};
+
+struct consumer_metadata_cache {
+ /* Current version of the metadata cache. */
uint64_t version;
/*
- * The upper-limit of data written inside the buffer.
- *
- * With the total_bytes_written it allows us to keep track of when the
- * cache contains contiguous metadata ready to be sent to the RB.
+ * Size is the upper-limit of data written inside the buffer.
* All cached data is contiguous.
*/
- uint64_t max_offset;
+ struct lttng_dynamic_buffer contents;
/*
* Lock to update the metadata cache and push into the ring_buffer
* (ustctl_write_metadata_to_channel).
pthread_mutex_t lock;
};
-int consumer_metadata_cache_write(struct lttng_consumer_channel *channel,
+enum consumer_metadata_cache_write_status
+consumer_metadata_cache_write(struct consumer_metadata_cache *cache,
unsigned int offset, unsigned int len, uint64_t version,
- char *data);
+ const char *data);
int consumer_metadata_cache_allocate(struct lttng_consumer_channel *channel);
void consumer_metadata_cache_destroy(struct lttng_consumer_channel *channel);
int consumer_metadata_cache_flushed(struct lttng_consumer_channel *channel,