[babeltrace.git] / include / babeltrace / ctf-ir / event.h

#ifndef BABELTRACE_CTF_IR_EVENT_H
#define BABELTRACE_CTF_IR_EVENT_H

/*
 * BabelTrace - CTF IR: Event
 *
 * Copyright 2013, 2014 Jérémie Galarneau <jeremie.galarneau@efficios.com>
 *
 * Author: Jérémie Galarneau <jeremie.galarneau@efficios.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 * The Common Trace Format (CTF) Specification is available at
 * http://www.efficios.com/ctf
 */

#include <stdint.h>
#include <stddef.h>

#ifdef __cplusplus
extern "C" {
#endif

struct bt_value;
struct bt_clock_class;

/**
@defgroup ctfirevent CTF IR event
@ingroup ctfir
@brief CTF IR event.

@code
#include <babeltrace/ctf-ir/event.h>
@endcode

A CTF IR <strong><em>event</em></strong> is a container of event
fields:

- <strong>Stream event header</strong> field, described by the
  <em>stream event header field type</em> of a
  \link ctfirstreamclass CTF IR stream class\endlink.
- <strong>Stream event context</strong> field, described by the
  <em>stream event context field type</em> of a stream class.
- <strong>Event context</strong> field, described by the
  <em>event context field type</em> of a
  \link ctfireventclass CTF IR event class\endlink.
- <strong>Event payload</strong>, described by the
  <em>event payload field type</em> of an event class.

As a reminder, here's the structure of a CTF packet:

@imgpacketstructure

You can create a CTF IR event \em from a
\link ctfireventclass CTF IR event class\endlink with
bt_event_create(). The event class you use to create an event
object becomes its parent.

If the \link ctfirtraceclass CTF IR trace class\endlink of an event
object (parent of its \link ctfirstreamclass CTF IR stream class\endlink,
which is the parent of its event class) was created by a
\link ctfwriter CTF writer\endlink object, then the only possible
action you can do with this event object is to append it to a
\link ctfirstream CTF IR stream\endlink with
bt_stream_append_event(). Otherwise, you can create an event
notification with bt_notification_event_create(). The event you pass
to this function \em must have an attached packet object first.

You can attach a \link ctfirpacket CTF IR packet object\endlink to an
event object with bt_event_set_packet().

A CTF IR event has a mapping of
\link ctfirclockvalue CTF IR clock values\endlink. A clock value is
an instance of a specific
\link ctfirclockclass CTF IR clock class\endlink when the event is
emitted. You can set an event object's clock value with
bt_event_set_clock_value().

As with any Babeltrace object, CTF IR event objects have
<a href="https://en.wikipedia.org/wiki/Reference_counting">reference
counts</a>. See \ref refs to learn more about the reference counting
management of Babeltrace objects.

bt_notification_event_create() \em freezes its event parameter on
success. You cannot modify a frozen event object: it is considered
immutable, except for \link refs reference counting\endlink.

@sa ctfireventclass
@sa ctfirpacket

@file
@brief CTF IR event type and functions.
@sa ctfirevent

@addtogroup ctfirevent
@{
*/

/**
@struct bt_event
@brief A CTF IR event.
@sa ctfirevent
*/
struct bt_event;
struct bt_clock;
struct bt_clock_value;
struct bt_event_class;
struct bt_field;
struct bt_field_type;
struct bt_stream_class;
struct bt_packet;

/**
@name Creation and parent access functions
@{
*/

/**
@brief  Creates a default CTF IR event from the CTF IR event class
	\p event_class.

\p event_class \em must have a parent
\link ctfirstreamclass CTF IR stream class\endlink.

On success, the four fields of the created event object are not set. You
can set them with bt_event_set_header(),
bt_event_set_stream_event_context(),
bt_event_set_event_context(), and bt_event_set_event_payload().

This function tries to resolve the needed
\link ctfirfieldtypes CTF IR field type\endlink of the dynamic field
types that are found anywhere in the context or payload field
types of \p event_class and in the root field types of the
parent stream class of \p event_class. If any automatic resolving fails,
this function fails. This means that, if any dynamic field type need
a field type which should be found in the trace packet header root
field type, and if the parent stream class of \p event_class was not
added to a \link ctfirtraceclass CTF IR trace class\endlink yet
with bt_trace_add_stream_class(), then this function fails.

@param[in] event_class	CTF IR event class to use to create the
			CTF IR event.
@returns		Created event object, or \c NULL on error.

@prenotnull{event_class}
@pre \p event_class has a parent stream class.
@postsuccessrefcountret1
*/
extern struct bt_event *bt_event_create(
		struct bt_event_class *event_class);

/**
@brief	Returns the parent CTF IR event class of the CTF IR event
	\p event.

This function returns a reference to the event class which was used to
create the event object in the first place with bt_event_create().

@param[in] event	Event of which to get the parent event class.
@returns		Parent event class of \p event,
			or \c NULL on error.

@prenotnull{event}
@postrefcountsame{event}
@postsuccessrefcountretinc
*/
extern struct bt_event_class *bt_event_get_class(
		struct bt_event *event);

/**
@brief	Returns the CTF IR packet associated to the CTF IR event
	\p event.

This function returns a reference to the event class which was set to
\p event in the first place with bt_event_set_packet().

@param[in] event	Event of which to get the associated packet.
@returns		Packet associated to \p event,
			or \c NULL if no packet is associated to
			\p event or on error.

@prenotnull{event}
@postrefcountsame{event}
@postsuccessrefcountretinc

@sa bt_event_set_packet(): Associates a given event to a given
	packet.
*/
extern struct bt_packet *bt_event_get_packet(
		struct bt_event *event);

/**
@brief	Associates the CTF IR event \p event to the CTF IR packet
	\p packet.

The \link ctfirstreamclass CTF IR stream class\endlink of the
parent \link ctfirstream CTF IR stream\endlink of \p packet \em must
be the same as the parent stream class of the
\link ctfireventclass CTF IR event class\endlink returned
by bt_event_get_class() for \p event.

You \em must call this function to create an event-packet association
before you call bt_notification_event_create() with \p event.

On success, this function also sets the parent stream object of
\p event to the parent stream of \p packet.

@param[in] event	Event to which to associate \p packet.
@param[in] packet	Packet to associate to \p event.
@returns		0 on success, or a negative value on error.

@prenotnull{event}
@prenotnull{packet}
@prehot{event}
@pre The parent stream class of \p packet is the same as the parent
	stream class of \p event.
@postsuccessrefcountretinc

@sa bt_event_get_packet(): Returns the associated packet of a
	given event object.
*/
extern int bt_event_set_packet(struct bt_event *event,
		struct bt_packet *packet);

/**
@brief	Returns the parent CTF IR stream associated to the CTF IR event
	\p event.

@param[in] event	Event of which to get the parent stream.
@returns		Parent stream of \p event, or \c NULL on error.

@prenotnull{event}
@postrefcountsame{event}
@postsuccessrefcountretinc
*/
extern struct bt_stream *bt_event_get_stream(
		struct bt_event *event);

/** @} */

/**
@name Contained fields functions
@{
*/

/**
@brief	Returns the stream event header field of the CTF IR event
	\p event.

@param[in] event	Event of which to get the stream event header
			field.
@returns		Stream event header field of \p event,
			or \c NULL if the stream event header
			field is not set or on error.

@prenotnull{event}
@postrefcountsame{event}
@postsuccessrefcountretinc

@sa bt_event_get_header(): Sets the stream event header
	field of a given event.
*/
extern struct bt_field *bt_event_get_header(
		struct bt_event *event);

/**
@brief	Sets the stream event header field of the CTF IR event
	\p event to \p header, or unsets the current stream event header field
	from \p event.

If \p header is not \c NULL, the field type of \p header, as returned by
bt_field_get_type(), \em must be equivalent to the field type returned by
bt_stream_class_get_event_header_type() for the parent stream class
of \p event.

@param[in] event	Event of which to set the stream event header
			field.
@param[in] header	Stream event header field.
@returns		0 on success, or a negative value on error.

@prenotnull{event}
@prehot{event}
@pre <strong>\p header, if not \c NULL</strong>, has a field type equivalent to
	the field type returned by bt_stream_class_get_event_header_type()
	for the parent stream class of \p event.
@postrefcountsame{event}
@post <strong>On success, if \p header is not \c NULL</strong>,
	the reference count of \p header is incremented.

@sa bt_event_get_header(): Returns the stream event header field
	of a given event.
*/
extern int bt_event_set_header(struct bt_event *event,
		struct bt_field *header);

/**
@brief	Returns the stream event context field of the CTF IR event
	\p event.

@param[in] event	Event of which to get the stream event context
			field.
@returns		Stream event context field of \p event,
			or \c NULL if the stream event context
			field is not set or on error.

@prenotnull{event}
@postrefcountsame{event}
@postsuccessrefcountretinc

@sa bt_event_set_stream_event_context(): Sets the stream event context
	field of a given event.
*/
extern struct bt_field *bt_event_get_stream_event_context(
		struct bt_event *event);

/**
@brief	Sets the stream event context field of the CTF IR event
	\p event to \p context, or unsets the current stream event context field
	from \p event.

If \p context is not \c NULL, the field type of \p context, as returned by
bt_field_get_type(), \em must be equivalent to the field type returned by
bt_stream_class_get_event_context_type() for the parent stream class
of \p event.

@param[in] event	Event of which to set the stream event context field.
@param[in] context	Stream event context field.
@returns		0 on success, or a negative value on error.

@prenotnull{event}
@prehot{event}
@pre <strong>\p context, if not \c NULL</strong>, has a field type equivalent to
	the field type returned by bt_stream_class_get_event_context_type()
	for the parent stream class of \p event.
@postrefcountsame{event}
@post <strong>On success, if \p context is not \c NULL</strong>, the reference
	count of \p context is incremented.

@sa bt_event_get_stream_event_context(): Returns the stream event context
	field of a given event.
*/
extern int bt_event_set_stream_event_context(struct bt_event *event,
		struct bt_field *context);

/**
@brief	Returns the event context field of the CTF IR event \p event.

@param[in] event	Event of which to get the context field.
@returns		Event context field of \p event, or \c NULL if the
			event context field is not set or on error.

@prenotnull{event}
@postrefcountsame{event}
@postsuccessrefcountretinc

@sa bt_event_set_event_context(): Sets the event context field of a given
	event.
*/
extern struct bt_field *bt_event_get_event_context(
		struct bt_event *event);

/**
@brief	Sets the event context field of the CTF IR event \p event to \p context,
	or unsets the current event context field from \p event.

If \p context is not \c NULL, the field type of \p context, as returned by
bt_field_get_type(), \em must be equivalent to the field type returned by
bt_event_class_get_context_type() for the parent class of \p event.

@param[in] event	Event of which to set the context field.
@param[in] context	Event context field.
@returns		0 on success, or a negative value on error.

@prenotnull{event}
@prehot{event}
@pre <strong>\p context, if not \c NULL</strong>, has a field type equivalent to
	the field type returned by bt_event_class_get_context_type() for the
	parent class of \p event.
@postrefcountsame{event}
@post <strong>On success, if \p context is not \c NULL</strong>, the reference
	count of \p context is incremented.

@sa bt_event_get_context(): Returns the context field of a given event.
*/
extern int bt_event_set_event_context(struct bt_event *event,
		struct bt_field *context);

/**
@brief	Returns the payload field of the CTF IR event \p event.

@param[in] event	Event of which to get the payload field.
@returns		Payload field of \p event, or \c NULL if the payload
			field is not set or on error.

@prenotnull{event}
@postrefcountsame{event}
@postsuccessrefcountretinc

@sa bt_event_set_event_payload(): Sets the payload field of a given
	event.
*/
extern struct bt_field *bt_event_get_event_payload(
		struct bt_event *event);

/**
@brief	Sets the payload field of the CTF IR event \p event to \p payload,
	or unsets the current event payload field from \p event.

If \p payload is not \c NULL, the field type of \p payload, as returned by
bt_field_get_type(), \em must be equivalent to the field type returned by
bt_event_class_get_payload_type() for the parent class of \p event.

@param[in] event	Event of which to set the payload field.
@param[in] payload	Event payload field.
@returns		0 on success, or a negative value on error.

@prenotnull{event}
@prehot{event}
@pre <strong>\p payload, if not \c NULL</strong>, has a field type equivalent to
	the field typereturned by bt_event_class_get_payload_type() for the
	parent class of \p event.
@postrefcountsame{event}
@post <strong>On success, if \p payload is not \c NULL</strong>, the reference
	count of \p payload is incremented.

@sa bt_event_get_payload(): Returns the payload field of a given event.
*/
extern int bt_event_set_event_payload(struct bt_event *event,
		struct bt_field *payload);

/** @cond DOCUMENT */

/*
 * TODO: Doxygenize.
 *
 * bt_event_get_payload: get an event's field.
 *
 * Returns the field matching "name". bt_put() must be called on the
 * returned value.
 *
 * @param event Event instance.
 * @param name Event field name, see notes.
 *
 * Returns a field instance on success, NULL on error.
 *
 * Note: Passing a name will cause the function to perform a look-up by
 *	name assuming the event's payload is a structure. This will return
 *	the raw payload instance if name is NULL.
 */
extern struct bt_field *bt_event_get_payload(struct bt_event *event,
		const char *name);

/*
 * TODO: Doxygenize.
 *
 * bt_event_get_payload_by_index: Get event's field by index.
 *
 * Returns the field associated with the provided index. bt_put()
 * must be called on the returned value. The indexes to be provided are
 * the same as can be retrieved from the event class.
 *
 * @param event Event.
 * @param index Index of field.
 *
 * Returns the event's field, NULL on error.
 *
 * Note: Will return an error if the payload's type is not a structure.
 */
extern struct bt_field *bt_event_get_payload_by_index(
		struct bt_event *event, uint64_t index);

/*
 * TODO: Doxygenize.
 *
 * bt_event_set_payload: set an event's field.
 *
 * Set a manually allocated field as an event's payload. The event will share
 * the field's ownership by using its reference count.
 * bt_put() must be called on the returned value.
 *
 * @param event Event instance.
 * @param name Event field name, see notes.
 * @param value Instance of a field whose type corresponds to the event's field.
 *
 * Returns 0 on success, a negative value on error.
 *
 * Note: The function will return an error if a name is provided and the payload
 *	type is not a structure. If name is NULL, the payload field will be set
 *	directly and must match the event class' payload's type.
 */
extern int bt_event_set_payload(struct bt_event *event,
		const char *name,
		struct bt_field *value);

/** @endcond */

/** @} */

/**
@name Clock value functions
@{
*/

/**
@brief	Returns the value, as of the CTF IR event \p event, of the
	clock described by the
	\link ctfirclockclass CTF IR clock class\endlink \p clock_class.

@param[in] event	Event of which to get the value of the clock
			described by \p clock_class.
@param[in] clock_class	Class of the clock of which to get the value.
@returns		Value of the clock described by \p clock_class
			as of \p event.

@prenotnull{event}
@prenotnull{clock_class}
@postrefcountsame{event}
@postrefcountsame{clock_class}
@postsuccessrefcountretinc

@sa bt_event_set_clock_value(): Sets the clock value of a given event.
*/
extern struct bt_clock_value *bt_event_get_clock_value(
		struct bt_event *event,
		struct bt_clock_class *clock_class);

/**
@brief	Sets the value, as of the CTF IR event \p event, of the
	clock described by its \link ctfirclockclass CTF IR
	clock class\endlink.

@param[in] event	Event of which to set the value of the clock
			described by the clock class of \p clock_value.
@param[in] clock_value	Value of the clock described by its clock class
			as of \p event.
@returns		0 on success, or a negative value on error.

@prenotnull{event}
@prenotnull{clock_value}
@prehot{event}
@postrefcountsame{event}

@sa bt_event_get_clock_value(): Returns the clock value of
	a given event.
*/
extern int bt_event_set_clock_value(
		struct bt_event *event,
		struct bt_clock_value *clock_value);

/** @} */

/** @} */

/* Pre-2.0 CTF writer compatibility */
#define bt_ctf_event bt_event
#define bt_ctf_event_create bt_event_create
#define bt_ctf_event_get_payload bt_event_get_payload
#define bt_ctf_event_set_payload bt_event_set_payload

#ifdef __cplusplus
}
#endif

#endif /* BABELTRACE_CTF_IR_EVENT_H */