Move to kernel style SPDX license identifiers

[babeltrace.git] / include / babeltrace2-ctf-writer / writer.h

/*
 * SPDX-License-Identifier: MIT
 *
 * Copyright (C) 2010-2019 EfficiOS Inc. and Linux Foundation
 */

#ifndef BABELTRACE2_CTF_WRITER_WRITER_H
#define BABELTRACE2_CTF_WRITER_WRITER_H

#include <babeltrace2-ctf-writer/field-types.h>
#include <babeltrace2-ctf-writer/stream-class.h>
#include <babeltrace2-ctf-writer/stream.h>
#include <babeltrace2-ctf-writer/trace.h>

#ifdef __cplusplus
extern "C" {
#endif

struct bt_ctf_writer;
struct bt_ctf_stream;
struct bt_ctf_stream_class;
struct bt_ctf_clock;

/*
 * bt_ctf_writer_create: create a writer instance.
 *
 * Allocate a new writer that will produce a trace in the given path.
 * The creation of a writer sets its reference count to 1.
 *
 * @param path Path to the trace's containing folder (string is copied).
 *
 * Returns an allocated writer on success, NULL on error.
 */
extern struct bt_ctf_writer *bt_ctf_writer_create(const char *path);

/*
 * bt_ctf_writer_get_trace: Get a writer's associated trace.
 *
 * @param writer Writer instance.
 *
 * Return the writer's associated instance, NULL on error.
 */
extern struct bt_ctf_trace *bt_ctf_writer_get_trace(
		struct bt_ctf_writer *writer);

/*
 * bt_ctf_writer_create_stream: create a stream instance.
 *
 * Allocate a new stream instance and register it to the writer. The creation of
 * a stream sets its reference count to 1.
 *
 * @param writer Writer instance.
 * @param stream_class Stream class to instantiate.
 *
 * Returns an allocated stream on success, NULL on error.
 */
extern struct bt_ctf_stream *bt_ctf_writer_create_stream(
		struct bt_ctf_writer *writer,
		struct bt_ctf_stream_class *stream_class);

/*
 * bt_ctf_writer_add_environment_field: add an environment field to the trace.
 *
 * Add an environment field to the trace. The name and value parameters are
 * copied.
 *
 * @param writer Writer instance.
 * @param name Name of the environment field (will be copied).
 * @param value Value of the environment field (will be copied).
 *
 * Returns 0 on success, a negative value on error.
 */
extern int bt_ctf_writer_add_environment_field(struct bt_ctf_writer *writer,
		const char *name,
		const char *value);

/*
 * bt_ctf_writer_add_environment_field_int64: add an environment field to the trace.
 *
 * Add an environment field to the trace. The name and value parameters are
 * copied.
 *
 * @param writer Writer instance.
 * @param name Name of the environment field (will be copied).
 * @param value Value of the environment field.
 *
 * Returns 0 on success, a negative value on error.
 */
extern int bt_ctf_writer_add_environment_field_int64(
		struct bt_ctf_writer *writer,
		const char *name,
		int64_t value);

/*
 * bt_ctf_writer_add_clock: add a clock to the trace.
 *
 * Add a clock to the trace. Clocks assigned to stream classes must be
 * registered to the writer.
 *
 * @param writer Writer instance.
 * @param clock Clock to add to the trace.
 *
 * Returns 0 on success, a negative value on error.
 */
extern int bt_ctf_writer_add_clock(struct bt_ctf_writer *writer,
		struct bt_ctf_clock *clock);

/*
 * bt_ctf_writer_get_metadata_string: get meta-data string.
 *
 * Get the trace's TSDL meta-data. The caller assumes the ownership of the
 * returned string.
 *
 * @param writer Writer instance.
 *
 * Returns the metadata string on success, NULL on error.
 */
extern char *bt_ctf_writer_get_metadata_string(struct bt_ctf_writer *writer);

/*
 * bt_ctf_writer_flush_metadata: flush the trace's metadata to disk.
 *
 * Flush the trace's metadata to the metadata file. Note that the metadata will
 * be flushed automatically when the Writer instance is released (last call to
 * bt_ctf_writer_put).
 *
 * @param writer Writer instance.
 */
extern void bt_ctf_writer_flush_metadata(struct bt_ctf_writer *writer);

/*
 * bt_ctf_writer_set_byte_order: set a field type's byte order.
 *
 * Set the trace's byte order. Defaults to the host machine's endianness.
 *
 * @param writer Writer instance.
 * @param byte_order Trace's byte order.
 *
 * Returns 0 on success, a negative value on error.
 *
 * Note: byte_order must not be BT_CTF_BYTE_ORDER_NATIVE since, according
 * to the CTF specification, is defined as "the byte order described in the
 * trace description".
 */
extern int bt_ctf_writer_set_byte_order(struct bt_ctf_writer *writer,
		enum bt_ctf_byte_order byte_order);

/*
 * bt_ctf_writer_get and bt_ctf_writer_put: increment and decrement the
 * writer's reference count.
 *
 * You may also use bt_ctf_get() and bt_ctf_put() with writer objects.
 *
 * These functions ensure that the writer won't be destroyed while it
 * is in use. The same number of get and put (plus one extra put to
 * release the initial reference done at creation) have to be done to
 * destroy a writer.
 *
 * When the writer's reference count is decremented to 0 by a
 * bt_ctf_writer_put, the writer is freed.
 *
 * @param writer Writer instance.
 */

/* Pre-2.0 CTF writer compatibility */
static inline
void bt_ctf_writer_get(struct bt_ctf_writer *writer)
{
	bt_ctf_object_get_ref(writer);
}

/* Pre-2.0 CTF writer compatibility */
static inline
void bt_ctf_writer_put(struct bt_ctf_writer *writer)
{
	bt_ctf_object_put_ref(writer);
}

#ifdef __cplusplus
}
#endif

#endif /* BABELTRACE2_CTF_WRITER_WRITER_H */