common: compile libconfig as C++

[lttng-tools.git] / src / common / trace-chunk-registry.h

/*
 * Copyright (C) 2019 Jérémie Galarneau <jeremie.galarneau@efficios.com>
 *
 * SPDX-License-Identifier: LGPL-2.1-only
 *
 */

#ifndef LTTNG_TRACE_CHUNK_REGISTRY_H
#define LTTNG_TRACE_CHUNK_REGISTRY_H

#include <stddef.h>
#include <stdint.h>
#include <stdbool.h>
#include <common/macros.h>
#include <common/trace-chunk.h>

#ifdef __cplusplus
extern "C" {
#endif

struct lttng_trace_chunk_registry;

/*
 * Create an lttng_trace_chunk registry.
 *
 * A trace chunk registry maintains an association between a
 * (session_id, chunk_id) tuple and a trace chunk object. The chunk_id can
 * be "unset" in the case of an anonymous trace chunk.
 *
 * Note that a trace chunk registry holds no ownership of its trace
 * chunks. Trace chunks are unpublished when their last reference is released.
 * See the documentation of lttng_trace_chunk.
 *
 * Returns a trace chunk registry on success, NULL on error.
 *
 * Note that a trace chunk registry may only be accessed by an RCU thread.
 */
struct lttng_trace_chunk_registry *lttng_trace_chunk_registry_create(void);

/*
 * Destroy an lttng trace chunk registry. The registry must be emptied
 * (i.e. all references to the trace chunks it contains must be released) before
 * it is destroyed.
 */
void lttng_trace_chunk_registry_destroy(
		struct lttng_trace_chunk_registry *registry);

/*
 * Publish a trace chunk for a given session id.
 * A reference is acquired on behalf of the caller.
 *
 * The trace chunk that is returned is the published version of the trace
 * chunk. The chunk provided should be discarded on success and it's
 * published version used in its place.
 *
 * See the documentation of lttng_trace_chunk for more information on
 * the usage of the various parameters.
 *
 * Returns an lttng_trace_chunk on success, NULL on error.
 */
struct lttng_trace_chunk *lttng_trace_chunk_registry_publish_chunk(
		struct lttng_trace_chunk_registry *registry,
		uint64_t session_id, struct lttng_trace_chunk *chunk);

/*
 * Look-up a trace chunk by session_id and chunk_id.
 * A reference is acquired on behalf of the caller.
 *
 * Returns an lttng_trace_chunk on success, NULL if the chunk does not exist.
 */
struct lttng_trace_chunk *
lttng_trace_chunk_registry_find_chunk(
		const struct lttng_trace_chunk_registry *registry,
		uint64_t session_id, uint64_t chunk_id);

/*
 * Query the existence of a trace chunk by session_id and chunk_id.
 *
 * Returns 0 on success, a negative value on error.
 */
int lttng_trace_chunk_registry_chunk_exists(
		const struct lttng_trace_chunk_registry *registry,
		uint64_t session_id, uint64_t chunk_id, bool *chunk_exists);

/*
 * Look-up an anonymous trace chunk by session_id.
 * A reference is acquired on behalf of the caller.
 *
 * Returns an lttng_trace_chunk on success, NULL if the chunk does not exist.
 */
struct lttng_trace_chunk *
lttng_trace_chunk_registry_find_anonymous_chunk(
		const struct lttng_trace_chunk_registry *registry,
		uint64_t session_id);

unsigned int lttng_trace_chunk_registry_put_each_chunk(
		const struct lttng_trace_chunk_registry *registry);

#ifdef __cplusplus
}
#endif

#endif /* LTTNG_TRACE_CHUNK_REGISTRY_H */