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[babeltrace.git] / src / 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 <babeltrace2/babeltrace.h>
33 #include "common/babeltrace.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)(size_t request_sz,
197 uint8_t **buffer_addr, size_t *buffer_sz, void *data);
198
199 /**
200 * Repositions the underlying stream's position.
201 *
202 * This *optional* method repositions the underlying stream
203 * to a given absolute or relative position, as indicated by
204 * the whence directive.
205 *
206 * @param whence One of #bt_msg_iter_seek_whence values
207 * @param offset Offset to use for the given directive
208 * @param data User data
209 * @returns One of #bt_msg_iter_medium_status values
210 */
211 enum bt_msg_iter_medium_status (* seek)(
212 enum bt_msg_iter_seek_whence whence,
213 off_t offset, void *data);
214
215 /**
216 * Returns a stream instance (weak reference) for the given
217 * stream class.
218 *
219 * This is called after a packet header is read, and the
220 * corresponding stream class is found by the message
221 * iterator.
222 *
223 * @param stream_class Stream class of the stream to get
224 * @param stream_id Stream (instance) ID of the stream
225 * to get (-1ULL if not available)
226 * @param data User data
227 * @returns Stream instance (weak reference) or
228 * \c NULL on error
229 */
230 bt_stream * (* borrow_stream)(bt_stream_class *stream_class,
231 int64_t stream_id, void *data);
232 };
233
234 /** CTF message iterator. */
235 struct bt_msg_iter;
236
237 /**
238 * Creates a CTF message iterator.
239 *
240 * Upon successful completion, the reference count of \p trace is
241 * incremented.
242 *
243 * @param trace Trace to read
244 * @param max_request_sz Maximum buffer size, in bytes, to
245 * request to
246 * bt_msg_iter_medium_ops::request_bytes()
247 * at a time
248 * @param medops Medium operations
249 * @param medops_data User data (passed to medium operations)
250 * @returns New CTF message iterator on
251 * success, or \c NULL on error
252 */
253 BT_HIDDEN
254 struct bt_msg_iter *bt_msg_iter_create(struct ctf_trace_class *tc,
255 size_t max_request_sz, struct bt_msg_iter_medium_ops medops,
256 void *medops_data);
257
258 /**
259 * Destroys a CTF message iterator, freeing all internal resources.
260 *
261 * The registered trace's reference count is decremented.
262 *
263 * @param msg_iter CTF message iterator
264 */
265 BT_HIDDEN
266 void bt_msg_iter_destroy(struct bt_msg_iter *msg_iter);
267
268 /**
269 * Returns the next message from a CTF message iterator.
270 *
271 * Upon successful completion, #BT_MSG_ITER_STATUS_OK is
272 * returned, and the next message is written to \p msg.
273 * In this case, the caller is responsible for calling
274 * bt_message_put() on the returned message.
275 *
276 * If this function returns #BT_MSG_ITER_STATUS_AGAIN, the caller
277 * should make sure that data becomes available to its medium, and
278 * call this function again, until another status is returned.
279 *
280 * @param msg_iter CTF message iterator
281 * @param message Returned message if the function's
282 * return value is #BT_MSG_ITER_STATUS_OK
283 * @returns One of #bt_msg_iter_status values
284 */
285 BT_HIDDEN
286 enum bt_msg_iter_status bt_msg_iter_get_next_message(
287 struct bt_msg_iter *notit,
288 bt_self_message_iterator *msg_iter,
289 bt_message **message);
290
291 struct bt_msg_iter_packet_properties {
292 int64_t exp_packet_total_size;
293 int64_t exp_packet_content_size;
294 uint64_t stream_class_id;
295 int64_t data_stream_id;
296
297 struct {
298 uint64_t discarded_events;
299 uint64_t packets;
300 uint64_t beginning_clock;
301 uint64_t end_clock;
302 } snapshots;
303 };
304
305 BT_HIDDEN
306 enum bt_msg_iter_status bt_msg_iter_get_packet_properties(
307 struct bt_msg_iter *notit,
308 struct bt_msg_iter_packet_properties *props);
309
310 BT_HIDDEN
311 void bt_msg_iter_set_medops_data(struct bt_msg_iter *notit,
312 void *medops_data);
313
314 BT_HIDDEN
315 enum bt_msg_iter_status bt_msg_iter_seek(
316 struct bt_msg_iter *notit, off_t offset);
317
318 /*
319 * Resets the iterator so that the next requested medium bytes are
320 * assumed to be the first bytes of a new stream. Depending on
321 * bt_msg_iter_set_emit_stream_beginning_message(), the first message
322 * which this iterator emits after calling bt_msg_iter_reset() is of
323 * type `BT_MESSAGE_TYPE_STREAM_BEGINNING`.
324 */
325 BT_HIDDEN
326 void bt_msg_iter_reset(struct bt_msg_iter *notit);
327
328 /*
329 * Like bt_msg_iter_reset(), but preserves stream-dependent state.
330 */
331 BT_HIDDEN
332 void bt_msg_iter_reset_for_next_stream_file(struct bt_msg_iter *notit);
333
334 BT_HIDDEN
335 void bt_msg_iter_set_emit_stream_beginning_message(struct bt_msg_iter *notit,
336 bool val);
337
338 BT_HIDDEN
339 void bt_msg_iter_set_emit_stream_end_message(struct bt_msg_iter *notit,
340 bool val);
341
342 static inline
343 const char *bt_msg_iter_medium_status_string(
344 enum bt_msg_iter_medium_status status)
345 {
346 switch (status) {
347 case BT_MSG_ITER_MEDIUM_STATUS_EOF:
348 return "BT_MSG_ITER_MEDIUM_STATUS_EOF";
349 case BT_MSG_ITER_MEDIUM_STATUS_AGAIN:
350 return "BT_MSG_ITER_MEDIUM_STATUS_AGAIN";
351 case BT_MSG_ITER_MEDIUM_STATUS_INVAL:
352 return "BT_MSG_ITER_MEDIUM_STATUS_INVAL";
353 case BT_MSG_ITER_MEDIUM_STATUS_ERROR:
354 return "BT_MSG_ITER_MEDIUM_STATUS_ERROR";
355 case BT_MSG_ITER_MEDIUM_STATUS_OK:
356 return "BT_MSG_ITER_MEDIUM_STATUS_OK";
357 default:
358 return "(unknown)";
359 }
360 }
361
362 static inline
363 const char *bt_msg_iter_status_string(
364 enum bt_msg_iter_status status)
365 {
366 switch (status) {
367 case BT_MSG_ITER_STATUS_EOF:
368 return "BT_MSG_ITER_STATUS_EOF";
369 case BT_MSG_ITER_STATUS_AGAIN:
370 return "BT_MSG_ITER_STATUS_AGAIN";
371 case BT_MSG_ITER_STATUS_INVAL:
372 return "BT_MSG_ITER_STATUS_INVAL";
373 case BT_MSG_ITER_STATUS_ERROR:
374 return "BT_MSG_ITER_STATUS_ERROR";
375 case BT_MSG_ITER_STATUS_OK:
376 return "BT_MSG_ITER_STATUS_OK";
377 default:
378 return "(unknown)";
379 }
380 }
381
382 #endif /* CTF_MSG_ITER_H */
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