Build fix: consumer: unused-but-set-variable warning
[lttng-tools.git] / src / common / consumer / consumer-metadata-cache.hpp
1 /*
2 * Copyright (C) 2013 Julien Desfossez <jdesfossez@efficios.com>
3 * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
4 *
5 * SPDX-License-Identifier: GPL-2.0-only
6 *
7 */
8
9 #ifndef CONSUMER_METADATA_CACHE_H
10 #define CONSUMER_METADATA_CACHE_H
11
12 #include <common/consumer/consumer.hpp>
13 #include <common/dynamic-buffer.hpp>
14
15 enum consumer_metadata_cache_write_status {
16 CONSUMER_METADATA_CACHE_WRITE_STATUS_ERROR = -1,
17 /*
18 * New metadata content was appended to the cache successfully.
19 * Previously available content remains valid.
20 */
21 CONSUMER_METADATA_CACHE_WRITE_STATUS_APPENDED_CONTENT = 0,
22 /*
23 * The new content pushed to the cache invalidated the content that
24 * was already present. The contents of the cache should be re-read.
25 */
26 CONSUMER_METADATA_CACHE_WRITE_STATUS_INVALIDATED,
27 /*
28 * A metadata cache write can simply overwrite an already existing
29 * section of the cache (and it should be a write-through with identical
30 * data). From the caller's standpoint, there is no change to the state
31 * of the cache.
32 */
33 CONSUMER_METADATA_CACHE_WRITE_STATUS_NO_CHANGE,
34 };
35
36 struct consumer_metadata_cache {
37 /* Current version of the metadata cache. */
38 uint64_t version;
39 /*
40 * Size is the upper-limit of data written inside the buffer.
41 * All cached data is contiguous.
42 */
43 struct lttng_dynamic_buffer contents;
44 /*
45 * Lock to update the metadata cache and push into the ring_buffer
46 * (lttng_ust_ctl_write_metadata_to_channel).
47 *
48 * This is nested INSIDE the consumer_data lock.
49 */
50 pthread_mutex_t lock;
51 };
52
53 enum consumer_metadata_cache_write_status
54 consumer_metadata_cache_write(struct consumer_metadata_cache *cache,
55 unsigned int offset, unsigned int len, uint64_t version,
56 const char *data);
57 int consumer_metadata_cache_allocate(struct lttng_consumer_channel *channel);
58 void consumer_metadata_cache_destroy(struct lttng_consumer_channel *channel);
59 int consumer_metadata_cache_flushed(struct lttng_consumer_channel *channel,
60 uint64_t offset, int timer);
61
62 #endif /* CONSUMER_METADATA_CACHE_H */
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