lib: rename "notification" -> "message"
[babeltrace.git] / plugins / ctf / common / msg-iter / msg-iter.h
1 #ifndef CTF_MSG_ITER_H
2 #define CTF_MSG_ITER_H
3
4 /*
5 * Babeltrace - CTF message iterator
6 * ¯¯¯¯¯ ¯¯¯¯
7 * Copyright (c) 2015-2016 EfficiOS Inc. and Linux Foundation
8 * Copyright (c) 2015-2016 Philippe Proulx <pproulx@efficios.com>
9 *
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:
16 *
17 * The above copyright notice and this permission notice shall be included in
18 * all copies or substantial portions of the Software.
19 *
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
26 * SOFTWARE.
27 */
28
29 #include <stdint.h>
30 #include <stdio.h>
31 #include <stddef.h>
32 #include <babeltrace/babeltrace.h>
33 #include <babeltrace/babeltrace-internal.h>
34
35 #include "../metadata/ctf-meta.h"
36
37 /**
38 * @file ctf-msg-iter.h
39 *
40 * CTF message iterator
41 * ¯¯¯¯¯ ¯¯¯¯
42 * This is a common internal API used by CTF source plugins. It allows
43 * one to get messages from a user-provided medium.
44 */
45
46 /**
47 * Medium operations status codes.
48 */
49 enum bt_msg_iter_medium_status {
50 /**
51 * End of file.
52 *
53 * The medium function called by the message iterator
54 * function reached the end of the file.
55 */
56 BT_MSG_ITER_MEDIUM_STATUS_EOF = 1,
57
58 /**
59 * There is no data available right now, try again later.
60 */
61 BT_MSG_ITER_MEDIUM_STATUS_AGAIN = 11,
62
63 /** Unsupported operation. */
64 BT_MSG_ITER_MEDIUM_STATUS_UNSUPPORTED = -3,
65
66 /** Invalid argument. */
67 BT_MSG_ITER_MEDIUM_STATUS_INVAL = -2,
68
69 /** General error. */
70 BT_MSG_ITER_MEDIUM_STATUS_ERROR = -1,
71
72 /** Everything okay. */
73 BT_MSG_ITER_MEDIUM_STATUS_OK = 0,
74 };
75
76 /**
77 * CTF message iterator API status code.
78 */
79 enum bt_msg_iter_status {
80 /**
81 * End of file.
82 *
83 * The medium function called by the message iterator
84 * function reached the end of the file.
85 */
86 BT_MSG_ITER_STATUS_EOF = BT_MSG_ITER_MEDIUM_STATUS_EOF,
87
88 /**
89 * There is no data available right now, try again later.
90 *
91 * Some condition resulted in the
92 * bt_msg_iter_medium_ops::request_bytes() user function not
93 * having access to any data now. You should retry calling the
94 * last called message iterator function once the situation
95 * is resolved.
96 */
97 BT_MSG_ITER_STATUS_AGAIN = BT_MSG_ITER_MEDIUM_STATUS_AGAIN,
98
99 /** Invalid argument. */
100 BT_MSG_ITER_STATUS_INVAL = BT_MSG_ITER_MEDIUM_STATUS_INVAL,
101
102 /** Unsupported operation. */
103 BT_MSG_ITER_STATUS_UNSUPPORTED = BT_MSG_ITER_MEDIUM_STATUS_UNSUPPORTED,
104
105 /** General error. */
106 BT_MSG_ITER_STATUS_ERROR = BT_MSG_ITER_MEDIUM_STATUS_ERROR,
107
108 /** Everything okay. */
109 BT_MSG_ITER_STATUS_OK = 0,
110 };
111
112 /**
113 * CTF message iterator seek operation directives.
114 */
115 enum bt_msg_iter_seek_whence {
116 /**
117 * Set the iterator's position to an absolute offset in the underlying
118 * medium.
119 */
120 BT_MSG_ITER_SEEK_WHENCE_SET,
121 };
122
123 /**
124 * Medium operations.
125 *
126 * Those user functions are called by the message iterator
127 * functions to request medium actions.
128 */
129 struct bt_msg_iter_medium_ops {
130 /**
131 * Returns the next byte buffer to be used by the binary file
132 * reader to deserialize binary data.
133 *
134 * This function \em must be defined.
135 *
136 * The purpose of this function is to return a buffer of bytes
137 * to the message iterator, of a maximum of \p request_sz
138 * bytes. If this function cannot return a buffer of at least
139 * \p request_sz bytes, it may return a smaller buffer. In
140 * either cases, \p buffer_sz must be set to the returned buffer
141 * size (in bytes).
142 *
143 * The returned buffer's ownership remains the medium, in that
144 * it won't be freed by the message iterator functions. The
145 * returned buffer won't be modified by the message
146 * iterator functions either.
147 *
148 * When this function is called for the first time for a given
149 * file, the offset within the file is considered to be 0. The
150 * next times this function is called, the returned buffer's
151 * byte offset within the complete file must be the previous
152 * offset plus the last returned value of \p buffer_sz by this
153 * medium.
154 *
155 * This function must return one of the following statuses:
156 *
157 * - <b>#BT_MSG_ITER_MEDIUM_STATUS_OK</b>: Everything
158 * is okay, i.e. \p buffer_sz is set to a positive value
159 * reflecting the number of available bytes in the buffer
160 * starting at the address written in \p buffer_addr.
161 * - <b>#BT_MSG_ITER_MEDIUM_STATUS_AGAIN</b>: No data is
162 * available right now. In this case, the message
163 * iterator function called by the user returns
164 * #BT_MSG_ITER_STATUS_AGAIN, and it is the user's
165 * responsibility to make sure enough data becomes available
166 * before calling the \em same message iterator
167 * function again to continue the decoding process.
168 * - <b>#BT_MSG_ITER_MEDIUM_STATUS_EOF</b>: The end of
169 * the file was reached, and no more data will ever be
170 * available for this file. In this case, the message
171 * iterator function called by the user returns
172 * #BT_MSG_ITER_STATUS_EOF. This must \em not be
173 * returned when returning at least one byte of data to the
174 * caller, i.e. this must be returned when there's
175 * absolutely nothing left; should the request size be
176 * larger than what's left in the file, this function must
177 * return what's left, setting \p buffer_sz to the number of
178 * remaining bytes, and return
179 * #BT_MSG_ITER_MEDIUM_STATUS_EOF on the \em following
180 * call.
181 * - <b>#BT_MSG_ITER_MEDIUM_STATUS_ERROR</b>: A fatal
182 * error occured during this operation. In this case, the
183 * message iterator function called by the user returns
184 * #BT_MSG_ITER_STATUS_ERROR.
185 *
186 * If #BT_MSG_ITER_MEDIUM_STATUS_OK is not returned, the
187 * values of \p buffer_sz and \p buffer_addr are \em ignored by
188 * the caller.
189 *
190 * @param request_sz Requested buffer size (bytes)
191 * @param buffer_addr Returned buffer address
192 * @param buffer_sz Returned buffer's size (bytes)
193 * @param data User data
194 * @returns Status code (see description above)
195 */
196 enum bt_msg_iter_medium_status (* request_bytes)(
197 size_t request_sz, uint8_t **buffer_addr,
198 size_t *buffer_sz, void *data);
199
200 /**
201 * Repositions the underlying stream's position.
202 *
203 * This *optional* method repositions the underlying stream
204 * to a given absolute or relative position, as indicated by
205 * the whence directive.
206 *
207 * @param whence One of #bt_msg_iter_seek_whence values
208 * @param offset Offset to use for the given directive
209 * @param data User data
210 * @returns One of #bt_msg_iter_medium_status values
211 */
212 enum bt_msg_iter_medium_status (* seek)(
213 enum bt_msg_iter_seek_whence whence,
214 off_t offset, void *data);
215
216 /**
217 * Returns a stream instance (weak reference) for the given
218 * stream class.
219 *
220 * This is called after a packet header is read, and the
221 * corresponding stream class is found by the message
222 * iterator.
223 *
224 * @param stream_class Stream class of the stream to get
225 * @param stream_id Stream (instance) ID of the stream
226 * to get (-1ULL if not available)
227 * @param data User data
228 * @returns Stream instance (weak reference) or
229 * \c NULL on error
230 */
231 bt_stream * (* borrow_stream)(
232 bt_stream_class *stream_class,
233 int64_t stream_id, void *data);
234 };
235
236 /** CTF message iterator. */
237 struct bt_msg_iter;
238
239 /**
240 * Creates a CTF message iterator.
241 *
242 * Upon successful completion, the reference count of \p trace is
243 * incremented.
244 *
245 * @param trace Trace to read
246 * @param max_request_sz Maximum buffer size, in bytes, to
247 * request to
248 * bt_msg_iter_medium_ops::request_bytes()
249 * at a time
250 * @param medops Medium operations
251 * @param medops_data User data (passed to medium operations)
252 * @returns New CTF message iterator on
253 * success, or \c NULL on error
254 */
255 BT_HIDDEN
256 struct bt_msg_iter *bt_msg_iter_create(struct ctf_trace_class *tc,
257 size_t max_request_sz, struct bt_msg_iter_medium_ops medops,
258 void *medops_data);
259
260 /**
261 * Destroys a CTF message iterator, freeing all internal resources.
262 *
263 * The registered trace's reference count is decremented.
264 *
265 * @param msg_iter CTF message iterator
266 */
267 BT_HIDDEN
268 void bt_msg_iter_destroy(struct bt_msg_iter *msg_iter);
269
270 /**
271 * Returns the next message from a CTF message iterator.
272 *
273 * Upon successful completion, #BT_MSG_ITER_STATUS_OK is
274 * returned, and the next message is written to \p msg.
275 * In this case, the caller is responsible for calling
276 * bt_message_put() on the returned message.
277 *
278 * If this function returns #BT_MSG_ITER_STATUS_AGAIN, the caller
279 * should make sure that data becomes available to its medium, and
280 * call this function again, until another status is returned.
281 *
282 * @param msg_iter CTF message iterator
283 * @param message Returned message if the function's
284 * return value is #BT_MSG_ITER_STATUS_OK
285 * @returns One of #bt_msg_iter_status values
286 */
287 BT_HIDDEN
288 enum bt_msg_iter_status bt_msg_iter_get_next_message(
289 struct bt_msg_iter *notit,
290 bt_self_message_iterator *msg_iter,
291 bt_message **message);
292
293 /**
294 * Returns the first packet header and context fields. This function
295 * never needs to call the `borrow_stream()` medium operation because
296 * it does not create packet or event objects.
297 *
298 * @param msg_iter CTF message iterator
299 * @param packet_header_field Packet header field (\c NULL if there's
300 * no packet header field)
301 * @param packet_context_field Packet context field (\c NULL if there's
302 * no packet context field)
303 * @returns One of #bt_msg_iter_status values
304 */
305 BT_HIDDEN
306 enum bt_msg_iter_status bt_msg_iter_borrow_packet_header_context_fields(
307 struct bt_msg_iter *notit,
308 bt_field **packet_header_field,
309 bt_field **packet_context_field);
310
311 struct bt_msg_iter_packet_properties {
312 uint64_t exp_packet_total_size;
313 uint64_t exp_packet_content_size;
314 uint64_t stream_class_id;
315 int64_t data_stream_id;
316
317 struct {
318 uint64_t discarded_events;
319 uint64_t packets;
320 uint64_t beginning_clock;
321 uint64_t end_clock;
322 } snapshots;
323 };
324
325 BT_HIDDEN
326 enum bt_msg_iter_status bt_msg_iter_get_packet_properties(
327 struct bt_msg_iter *notit,
328 struct bt_msg_iter_packet_properties *props);
329
330 BT_HIDDEN
331 void bt_msg_iter_set_medops_data(struct bt_msg_iter *notit,
332 void *medops_data);
333
334 BT_HIDDEN
335 enum bt_msg_iter_status bt_msg_iter_seek(
336 struct bt_msg_iter *notit, off_t offset);
337
338 /*
339 * Get the current packet's offset in bytes relative to the media's initial
340 * position.
341 */
342 BT_HIDDEN
343 off_t bt_msg_iter_get_current_packet_offset(
344 struct bt_msg_iter *notit);
345
346 /* Get the current packet's size (in bits). */
347 BT_HIDDEN
348 off_t bt_msg_iter_get_current_packet_size(
349 struct bt_msg_iter *notit);
350
351 /*
352 * Resets the iterator so that the next requested medium bytes are
353 * assumed to be the first bytes of a new stream. The first message
354 * which this iterator emits after calling bt_msg_iter_reset() is a
355 * BT_MESSAGE_TYPE_STREAM_BEGINNING one.
356 */
357 BT_HIDDEN
358 void bt_msg_iter_reset(struct bt_msg_iter *notit);
359
360 /*
361 * Notify the iterator that the trace class changed somehow (new
362 * stream/event classes).
363 */
364 BT_HIDDEN
365 void bt_msg_trace_class_changed(struct bt_msg_iter *notit);
366
367 static inline
368 const char *bt_msg_iter_medium_status_string(
369 enum bt_msg_iter_medium_status status)
370 {
371 switch (status) {
372 case BT_MSG_ITER_MEDIUM_STATUS_EOF:
373 return "BT_MSG_ITER_MEDIUM_STATUS_EOF";
374 case BT_MSG_ITER_MEDIUM_STATUS_AGAIN:
375 return "BT_MSG_ITER_MEDIUM_STATUS_AGAIN";
376 case BT_MSG_ITER_MEDIUM_STATUS_INVAL:
377 return "BT_MSG_ITER_MEDIUM_STATUS_INVAL";
378 case BT_MSG_ITER_MEDIUM_STATUS_ERROR:
379 return "BT_MSG_ITER_MEDIUM_STATUS_ERROR";
380 case BT_MSG_ITER_MEDIUM_STATUS_OK:
381 return "BT_MSG_ITER_MEDIUM_STATUS_OK";
382 default:
383 return "(unknown)";
384 }
385 }
386
387 static inline
388 const char *bt_msg_iter_status_string(
389 enum bt_msg_iter_status status)
390 {
391 switch (status) {
392 case BT_MSG_ITER_STATUS_EOF:
393 return "BT_MSG_ITER_STATUS_EOF";
394 case BT_MSG_ITER_STATUS_AGAIN:
395 return "BT_MSG_ITER_STATUS_AGAIN";
396 case BT_MSG_ITER_STATUS_INVAL:
397 return "BT_MSG_ITER_STATUS_INVAL";
398 case BT_MSG_ITER_STATUS_ERROR:
399 return "BT_MSG_ITER_STATUS_ERROR";
400 case BT_MSG_ITER_STATUS_OK:
401 return "BT_MSG_ITER_STATUS_OK";
402 default:
403 return "(unknown)";
404 }
405 }
406
407 #endif /* CTF_MSG_ITER_H */
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