5 * Babeltrace - CTF message iterator
7 * Copyright (c) 2015-2016 EfficiOS Inc. and Linux Foundation
8 * Copyright (c) 2015-2016 Philippe Proulx <pproulx@efficios.com>
10 * Permission is hereby granted, free of charge, to any person obtaining a copy
11 * of this software and associated documentation files (the "Software"), to deal
12 * in the Software without restriction, including without limitation the rights
13 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
14 * copies of the Software, and to permit persons to whom the Software is
15 * furnished to do so, subject to the following conditions:
17 * The above copyright notice and this permission notice shall be included in
18 * all copies or substantial portions of the Software.
20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
23 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
24 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
25 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
33 #include <babeltrace2/babeltrace.h>
34 #include "common/macros.h"
36 #include "../metadata/ctf-meta.h"
39 * @file ctf-msg-iter.h
41 * CTF message iterator
43 * This is a common internal API used by CTF source plugins. It allows
44 * one to get messages from a user-provided medium.
48 * Medium operations status codes. These use the same values as
51 enum ctf_msg_iter_medium_status
{
55 * The medium function called by the message iterator
56 * function reached the end of the file.
58 CTF_MSG_ITER_MEDIUM_STATUS_EOF
= 1,
61 * There is no data available right now, try again later.
63 CTF_MSG_ITER_MEDIUM_STATUS_AGAIN
= 11,
66 CTF_MSG_ITER_MEDIUM_STATUS_ERROR
= -1,
69 CTF_MSG_ITER_MEDIUM_STATUS_MEMORY_ERROR
= -12,
71 /** Everything okay. */
72 CTF_MSG_ITER_MEDIUM_STATUS_OK
= 0,
76 * CTF message iterator API status code.
78 enum ctf_msg_iter_status
{
82 * The medium function called by the message iterator
83 * function reached the end of the file.
85 CTF_MSG_ITER_STATUS_EOF
= CTF_MSG_ITER_MEDIUM_STATUS_EOF
,
88 * There is no data available right now, try again later.
90 * Some condition resulted in the
91 * ctf_msg_iter_medium_ops::request_bytes() user function not
92 * having access to any data now. You should retry calling the
93 * last called message iterator function once the situation
96 CTF_MSG_ITER_STATUS_AGAIN
= CTF_MSG_ITER_MEDIUM_STATUS_AGAIN
,
99 CTF_MSG_ITER_STATUS_ERROR
= CTF_MSG_ITER_MEDIUM_STATUS_ERROR
,
102 CTF_MSG_ITER_STATUS_MEMORY_ERROR
= CTF_MSG_ITER_MEDIUM_STATUS_MEMORY_ERROR
,
104 /** Everything okay. */
105 CTF_MSG_ITER_STATUS_OK
= CTF_MSG_ITER_MEDIUM_STATUS_OK
,
111 * Those user functions are called by the message iterator
112 * functions to request medium actions.
114 struct ctf_msg_iter_medium_ops
{
116 * Returns the next byte buffer to be used by the binary file
117 * reader to deserialize binary data.
119 * This function \em must be defined.
121 * The purpose of this function is to return a buffer of bytes
122 * to the message iterator, of a maximum of \p request_sz
123 * bytes. If this function cannot return a buffer of at least
124 * \p request_sz bytes, it may return a smaller buffer. In
125 * either cases, \p buffer_sz must be set to the returned buffer
128 * The returned buffer's ownership remains the medium, in that
129 * it won't be freed by the message iterator functions. The
130 * returned buffer won't be modified by the message
131 * iterator functions either.
133 * When this function is called for the first time for a given
134 * file, the offset within the file is considered to be 0. The
135 * next times this function is called, the returned buffer's
136 * byte offset within the complete file must be the previous
137 * offset plus the last returned value of \p buffer_sz by this
140 * This function must return one of the following statuses:
142 * - <b>#CTF_MSG_ITER_MEDIUM_STATUS_OK</b>: Everything
143 * is okay, i.e. \p buffer_sz is set to a positive value
144 * reflecting the number of available bytes in the buffer
145 * starting at the address written in \p buffer_addr.
146 * - <b>#CTF_MSG_ITER_MEDIUM_STATUS_AGAIN</b>: No data is
147 * available right now. In this case, the message
148 * iterator function called by the user returns
149 * #CTF_MSG_ITER_STATUS_AGAIN, and it is the user's
150 * responsibility to make sure enough data becomes available
151 * before calling the \em same message iterator
152 * function again to continue the decoding process.
153 * - <b>#CTF_MSG_ITER_MEDIUM_STATUS_EOF</b>: The end of
154 * the file was reached, and no more data will ever be
155 * available for this file. In this case, the message
156 * iterator function called by the user returns
157 * #CTF_MSG_ITER_STATUS_EOF. This must \em not be
158 * returned when returning at least one byte of data to the
159 * caller, i.e. this must be returned when there's
160 * absolutely nothing left; should the request size be
161 * larger than what's left in the file, this function must
162 * return what's left, setting \p buffer_sz to the number of
163 * remaining bytes, and return
164 * #CTF_MSG_ITER_MEDIUM_STATUS_EOF on the \em following
166 * - <b>#CTF_MSG_ITER_MEDIUM_STATUS_ERROR</b>: A fatal
167 * error occured during this operation. In this case, the
168 * message iterator function called by the user returns
169 * #CTF_MSG_ITER_STATUS_ERROR.
171 * If #CTF_MSG_ITER_MEDIUM_STATUS_OK is not returned, the
172 * values of \p buffer_sz and \p buffer_addr are \em ignored by
175 * @param request_sz Requested buffer size (bytes)
176 * @param buffer_addr Returned buffer address
177 * @param buffer_sz Returned buffer's size (bytes)
178 * @param data User data
179 * @returns Status code (see description above)
181 enum ctf_msg_iter_medium_status (* request_bytes
)(size_t request_sz
,
182 uint8_t **buffer_addr
, size_t *buffer_sz
, void *data
);
185 * Repositions the underlying stream's position.
187 * This *optional* method repositions the underlying stream
188 * to a given absolute position in the medium.
190 * @param offset Offset to use for the given directive
191 * @param data User data
192 * @returns One of #ctf_msg_iter_medium_status values
194 enum ctf_msg_iter_medium_status (* seek
)(off_t offset
, void *data
);
197 * Called when the message iterator wishes to inform the medium that it
198 * is about to start a new packet.
200 * After the iterator has called switch_packet, the following call to
201 * request_bytes must return the content at the start of the next
203 enum ctf_msg_iter_medium_status (* switch_packet
)(void *data
);
206 * Returns a stream instance (weak reference) for the given
209 * This is called after a packet header is read, and the
210 * corresponding stream class is found by the message
213 * @param stream_class Stream class of the stream to get
214 * @param stream_id Stream (instance) ID of the stream
215 * to get (-1ULL if not available)
216 * @param data User data
217 * @returns Stream instance (weak reference) or
220 bt_stream
* (* borrow_stream
)(bt_stream_class
*stream_class
,
221 int64_t stream_id
, void *data
);
224 /** CTF message iterator. */
228 * Creates a CTF message iterator.
230 * Upon successful completion, the reference count of \p trace is
233 * @param trace Trace to read
234 * @param max_request_sz Maximum buffer size, in bytes, to
236 * ctf_msg_iter_medium_ops::request_bytes()
238 * @param medops Medium operations
239 * @param medops_data User data (passed to medium operations)
240 * @returns New CTF message iterator on
241 * success, or \c NULL on error
244 struct ctf_msg_iter
*ctf_msg_iter_create(
245 struct ctf_trace_class
*tc
,
246 size_t max_request_sz
,
247 struct ctf_msg_iter_medium_ops medops
,
249 bt_logging_level log_level
,
250 bt_self_component
*self_comp
,
251 bt_self_message_iterator
*self_msg_iter
);
254 * Destroys a CTF message iterator, freeing all internal resources.
256 * The registered trace's reference count is decremented.
258 * @param msg_iter CTF message iterator
261 void ctf_msg_iter_destroy(struct ctf_msg_iter
*msg_iter
);
264 * Returns the next message from a CTF message iterator.
266 * Upon successful completion, #CTF_MSG_ITER_STATUS_OK is
267 * returned, and the next message is written to \p msg.
268 * In this case, the caller is responsible for calling
269 * bt_message_put() on the returned message.
271 * If this function returns #CTF_MSG_ITER_STATUS_AGAIN, the caller
272 * should make sure that data becomes available to its medium, and
273 * call this function again, until another status is returned.
275 * @param msg_iter CTF message iterator
276 * @param message Returned message if the function's
277 * return value is #CTF_MSG_ITER_STATUS_OK
278 * @returns One of #ctf_msg_iter_status values
281 enum ctf_msg_iter_status
ctf_msg_iter_get_next_message(
282 struct ctf_msg_iter
*msg_it
,
283 const bt_message
**message
);
285 struct ctf_msg_iter_packet_properties
{
286 int64_t exp_packet_total_size
;
287 int64_t exp_packet_content_size
;
288 uint64_t stream_class_id
;
289 int64_t data_stream_id
;
292 uint64_t discarded_events
;
294 uint64_t beginning_clock
;
300 enum ctf_msg_iter_status
ctf_msg_iter_get_packet_properties(
301 struct ctf_msg_iter
*msg_it
,
302 struct ctf_msg_iter_packet_properties
*props
);
305 enum ctf_msg_iter_status
ctf_msg_iter_curr_packet_first_event_clock_snapshot(
306 struct ctf_msg_iter
*msg_it
, uint64_t *first_event_cs
);
309 enum ctf_msg_iter_status
ctf_msg_iter_curr_packet_last_event_clock_snapshot(
310 struct ctf_msg_iter
*msg_it
, uint64_t *last_event_cs
);
313 enum ctf_msg_iter_status
ctf_msg_iter_seek(
314 struct ctf_msg_iter
*msg_it
, off_t offset
);
317 * Resets the iterator so that the next requested medium bytes are
318 * assumed to be the first bytes of a new stream. Depending on
319 * ctf_msg_iter_set_emit_stream_beginning_message(), the first message
320 * which this iterator emits after calling ctf_msg_iter_reset() is of
321 * type `CTF_MESSAGE_TYPE_STREAM_BEGINNING`.
324 void ctf_msg_iter_reset(struct ctf_msg_iter
*msg_it
);
327 * Like ctf_msg_iter_reset(), but preserves stream-dependent state.
330 void ctf_msg_iter_reset_for_next_stream_file(struct ctf_msg_iter
*msg_it
);
333 void ctf_msg_iter_set_dry_run(struct ctf_msg_iter
*msg_it
,
337 const char *ctf_msg_iter_medium_status_string(
338 enum ctf_msg_iter_medium_status status
)
341 case CTF_MSG_ITER_MEDIUM_STATUS_EOF
:
343 case CTF_MSG_ITER_MEDIUM_STATUS_AGAIN
:
345 case CTF_MSG_ITER_MEDIUM_STATUS_ERROR
:
347 case CTF_MSG_ITER_MEDIUM_STATUS_OK
:
355 const char *ctf_msg_iter_status_string(
356 enum ctf_msg_iter_status status
)
359 case CTF_MSG_ITER_STATUS_EOF
:
361 case CTF_MSG_ITER_STATUS_AGAIN
:
363 case CTF_MSG_ITER_STATUS_ERROR
:
365 case CTF_MSG_ITER_STATUS_OK
:
372 #endif /* CTF_MSG_ITER_H */