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1 | #ifndef BABELTRACE2_TRACE_IR_FIELD_PATH_H |
2 | #define BABELTRACE2_TRACE_IR_FIELD_PATH_H | |
3 | ||
4 | /* | |
5 | * Copyright (c) 2010-2019 EfficiOS Inc. and Linux Foundation | |
6 | * | |
7 | * Permission is hereby granted, free of charge, to any person obtaining a copy | |
8 | * of this software and associated documentation files (the "Software"), to deal | |
9 | * in the Software without restriction, including without limitation the rights | |
10 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
11 | * copies of the Software, and to permit persons to whom the Software is | |
12 | * furnished to do so, subject to the following conditions: | |
13 | * | |
14 | * The above copyright notice and this permission notice shall be included in | |
15 | * all copies or substantial portions of the Software. | |
16 | * | |
17 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
18 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
19 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
20 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
21 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
22 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
23 | * SOFTWARE. | |
24 | */ | |
25 | ||
26 | #ifndef __BT_IN_BABELTRACE_H | |
27 | # error "Please include <babeltrace2/babeltrace.h> instead." | |
28 | #endif | |
29 | ||
30 | #include <stdint.h> | |
31 | ||
32 | #include <babeltrace2/types.h> | |
33 | ||
34 | #ifdef __cplusplus | |
35 | extern "C" { | |
36 | #endif | |
37 | ||
38 | /*! | |
39 | @defgroup api-tir-field-path Field path | |
40 | @ingroup api-tir | |
41 | ||
42 | @brief | |
43 | Path to a \bt_field. | |
44 | ||
45 | A <strong><em>field path</em></strong> indicates how to reach a given | |
46 | \bt_field from a given <em>root scope</em>. | |
47 | ||
48 | More specifically, a field path indicates how to reach: | |
49 | ||
50 | - The length field of a \bt_darray_field (with a length field). | |
51 | - The selector field of a \bt_opt_field (with a selector field). | |
52 | - The selector field of a \bt_var_field (with a selector field). | |
53 | ||
54 | You can borrow the field path from the \ref api-tir-fc "classes" of such | |
55 | fields with | |
56 | bt_field_class_array_dynamic_with_length_field_borrow_length_field_path_const(), | |
57 | bt_field_class_option_with_selector_field_borrow_selector_field_path_const(), | |
58 | and | |
59 | bt_field_class_variant_with_selector_field_borrow_selector_field_path_const(). | |
60 | Note that the field path properties of those field classes only becomes | |
61 | available when the field class becomes part of an \bt_ev_cls or of a | |
62 | \bt_stream_cls. See | |
63 | \ref api-tir-fc-link "Field classes with links to other field classes". | |
64 | ||
65 | A field path is a \ref api-tir "trace IR" metadata object. | |
66 | ||
67 | A field path is a \ref api-fund-shared-object "shared object": get a | |
68 | new reference with bt_field_path_get_ref() and put an existing | |
69 | reference with bt_field_path_put_ref(). | |
70 | ||
71 | The type of a field path is #bt_field_path. | |
72 | ||
73 | <h1>Properties</h1> | |
74 | ||
75 | A field path has the following properties: | |
76 | ||
77 | <dl> | |
78 | <dt> | |
79 | \anchor api-tir-field-path-prop-root | |
80 | Root scope | |
81 | </dt> | |
82 | <dd> | |
83 | Indicates from which \bt_struct_field to start a lookup. | |
84 | ||
85 | See \ref api-tir-field-path-lookup-algo "Lookup algorithm" to | |
86 | learn more. | |
87 | ||
88 | Get a field path's root scope with bt_field_path_get_root_scope(). | |
89 | </dd> | |
90 | ||
91 | <dt> | |
92 | \anchor api-tir-field-path-prop-items | |
93 | Items | |
94 | </dt> | |
95 | <dd> | |
96 | Each item in a field path's item list indicates which action to take | |
97 | to follow the path to the linked \bt_field. | |
98 | ||
99 | See \ref api-tir-field-path-lookup-algo "Lookup algorithm" to | |
100 | learn more. | |
101 | ||
102 | Get the number of items in a field path with | |
103 | bt_field_path_get_item_count(). | |
104 | ||
105 | Borrow an item from a field path with | |
106 | bt_field_path_borrow_item_by_index_const(). This function | |
107 | returns the #bt_field_path_item type. | |
108 | ||
109 | A field path item is a \ref api-fund-unique-object "unique object": | |
110 | it belongs to the field path which contains it. | |
111 | </dd> | |
112 | </dl> | |
113 | ||
114 | <h1>\anchor api-tir-field-path-lookup-algo Lookup algorithm</h1> | |
115 | ||
116 | The field resolution algorithm using a field path is: | |
117 | ||
118 | -# Use the appropriate function to set a <em>current field</em> variable | |
119 | from the root scope (as returned by bt_field_path_get_root_scope()): | |
120 | ||
121 | <dl> | |
122 | <dt>#BT_FIELD_PATH_SCOPE_PACKET_CONTEXT</dt> | |
123 | <dd> | |
124 | bt_packet_borrow_context_field_const(). | |
125 | </dd> | |
126 | <dt>#BT_FIELD_PATH_SCOPE_EVENT_COMMON_CONTEXT</dt> | |
127 | <dd> | |
128 | bt_event_borrow_common_context_field_const(). | |
129 | </dd> | |
130 | <dt>#BT_FIELD_PATH_SCOPE_EVENT_SPECIFIC_CONTEXT</dt> | |
131 | <dd> | |
132 | bt_event_borrow_specific_context_field_const(). | |
133 | </dd> | |
134 | <dt>#BT_FIELD_PATH_SCOPE_EVENT_PAYLOAD</dt> | |
135 | <dd> | |
136 | bt_event_borrow_payload_field_const(). | |
137 | </dd> | |
138 | </dl> | |
139 | ||
140 | -# For each field path item (use bt_field_path_get_item_count() | |
141 | and bt_field_path_borrow_item_by_index_const()), depending on | |
142 | the item's type (as returned by bt_field_path_item_get_type()): | |
143 | ||
144 | <dl> | |
145 | <dt>#BT_FIELD_PATH_ITEM_TYPE_INDEX</dt> | |
146 | <dd> | |
147 | Call bt_field_path_item_index_get_index() to get the item's | |
148 | index value. | |
149 | ||
150 | Depending on the current field's class's type (as | |
151 | returned by bt_field_get_class_type()): | |
152 | ||
153 | <dl> | |
154 | <dt>\bt_c_struct_fc</dt> | |
155 | <dd> | |
156 | Call bt_field_structure_borrow_member_field_by_index_const() | |
157 | with the current field and with the item's index to set the | |
158 | new current field. | |
159 | </dd> | |
160 | ||
161 | <dt>\bt_c_var_fc</dt> | |
162 | <dd> | |
163 | Call bt_field_variant_borrow_selected_option_field_const() | |
164 | with the current field to set the new current field. | |
165 | </dd> | |
166 | </dl> | |
167 | </dd> | |
168 | ||
169 | <dt>#BT_FIELD_PATH_ITEM_TYPE_CURRENT_ARRAY_ELEMENT</dt> | |
170 | <dd> | |
171 | Call bt_field_array_borrow_element_field_by_index_const() | |
172 | with the index of the field eventually containing the | |
173 | field with a link (\bt_darray_field, \bt_opt_field, or | |
174 | \bt_var_field) and the current field to set the new current | |
175 | field. | |
176 | </dd> | |
177 | ||
178 | <dt>#BT_FIELD_PATH_ITEM_TYPE_CURRENT_OPTION_CONTENT</dt> | |
179 | <dd> | |
180 | Call bt_field_option_borrow_field_const() with the current | |
181 | field to set the new current field. | |
182 | </dd> | |
183 | </dl> | |
184 | ||
185 | After applying this procedure, the current field is the linked | |
186 | field. | |
187 | */ | |
188 | ||
189 | /*! @{ */ | |
190 | ||
191 | /*! | |
192 | @name Field path | |
193 | @{ | |
194 | ||
195 | @typedef struct bt_field_path bt_field_path; | |
196 | ||
197 | @brief | |
198 | Field path. | |
199 | ||
200 | */ | |
201 | ||
202 | /*! | |
203 | @brief | |
204 | Field path scopes. | |
205 | */ | |
206 | typedef enum bt_field_path_scope { | |
207 | /*! | |
208 | @brief | |
209 | Packet context. | |
210 | */ | |
211 | BT_FIELD_PATH_SCOPE_PACKET_CONTEXT = 0, | |
212 | ||
213 | /*! | |
214 | @brief | |
215 | Event common context. | |
216 | */ | |
217 | BT_FIELD_PATH_SCOPE_EVENT_COMMON_CONTEXT = 1, | |
218 | ||
219 | /*! | |
220 | @brief | |
221 | Event specific context. | |
222 | */ | |
223 | BT_FIELD_PATH_SCOPE_EVENT_SPECIFIC_CONTEXT = 2, | |
224 | ||
225 | /*! | |
226 | @brief | |
227 | Event payload. | |
228 | */ | |
229 | BT_FIELD_PATH_SCOPE_EVENT_PAYLOAD = 3, | |
230 | } bt_field_path_scope; | |
231 | ||
232 | /*! | |
233 | @brief | |
234 | Returns the root scope of the field path \bt_p{field_path}. | |
235 | ||
236 | See the \ref api-tir-field-path-prop-root "root scope" property. | |
237 | ||
238 | @param[in] field_path | |
239 | Field path of which to get the root scope. | |
240 | ||
241 | @returns | |
242 | Root scope of \bt_p{field_path}. | |
243 | ||
244 | @bt_pre_not_null{field_path} | |
245 | */ | |
246 | extern bt_field_path_scope bt_field_path_get_root_scope( | |
247 | const bt_field_path *field_path); | |
248 | ||
249 | /*! | |
250 | @brief | |
251 | Returns the number of items contained in the field path | |
252 | \bt_p{field_path}. | |
253 | ||
254 | See the \ref api-tir-field-path-prop-items "items" property. | |
255 | ||
256 | @param[in] field_path | |
257 | Field path of which to get the number of contained items. | |
258 | ||
259 | @returns | |
260 | Number of contained items in \bt_p{field_path}. | |
261 | ||
262 | @bt_pre_not_null{field_path} | |
263 | */ | |
264 | extern uint64_t bt_field_path_get_item_count( | |
265 | const bt_field_path *field_path); | |
266 | ||
267 | /*! | |
268 | @brief | |
269 | Borrows the item at index \bt_p{index} from the | |
270 | field path \bt_p{field_path}. | |
271 | ||
272 | See the \ref api-tir-field-path-prop-items "items" property. | |
273 | ||
274 | @param[in] field_path | |
275 | Field path from which to borrow the item at index \bt_p{index}. | |
276 | @param[in] index | |
277 | Index of the item to borrow from \bt_p{field_path}. | |
278 | ||
279 | @returns | |
280 | @parblock | |
281 | \em Borrowed reference of the item of | |
282 | \bt_p{field_path} at index \bt_p{index}. | |
283 | ||
284 | The returned pointer remains valid as long as \bt_p{field_path} | |
285 | exists. | |
286 | @endparblock | |
287 | ||
288 | @bt_pre_not_null{field_path} | |
289 | @pre | |
290 | \bt_p{index} is less than the number of items in | |
291 | \bt_p{field_path} (as returned by bt_field_path_get_item_count()). | |
292 | ||
293 | @sa bt_field_path_get_item_count() — | |
294 | Returns the number of items contained in a field path. | |
295 | */ | |
296 | extern const bt_field_path_item *bt_field_path_borrow_item_by_index_const( | |
297 | const bt_field_path *field_path, uint64_t index); | |
298 | ||
299 | /*! | |
300 | @brief | |
301 | Increments the \ref api-fund-shared-object "reference count" of | |
302 | the field path \bt_p{field_path}. | |
303 | ||
304 | @param[in] field_path | |
305 | @parblock | |
306 | Field path of which to increment the reference count. | |
307 | ||
308 | Can be \c NULL. | |
309 | @endparblock | |
310 | ||
311 | @sa bt_field_path_put_ref() — | |
312 | Decrements the reference count of a field path. | |
313 | */ | |
314 | extern void bt_field_path_get_ref(const bt_field_path *field_path); | |
315 | ||
316 | /*! | |
317 | @brief | |
318 | Decrements the \ref api-fund-shared-object "reference count" of | |
319 | the field path \bt_p{field_path}. | |
320 | ||
321 | @param[in] field_path | |
322 | @parblock | |
323 | Field path of which to decrement the reference count. | |
324 | ||
325 | Can be \c NULL. | |
326 | @endparblock | |
327 | ||
328 | @sa bt_field_path_get_ref() — | |
329 | Increments the reference count of a field path. | |
330 | */ | |
331 | extern void bt_field_path_put_ref(const bt_field_path *field_path); | |
332 | ||
333 | /*! | |
334 | @brief | |
335 | Decrements the reference count of the field path | |
336 | \bt_p{_field_path}, and then sets \bt_p{_field_path} to \c NULL. | |
337 | ||
338 | @param _field_path | |
339 | @parblock | |
340 | Field path of which to decrement the reference count. | |
341 | ||
342 | Can contain \c NULL. | |
343 | @endparblock | |
344 | ||
345 | @bt_pre_assign_expr{_field_path} | |
346 | */ | |
347 | #define BT_FIELD_PATH_PUT_REF_AND_RESET(_field_path) \ | |
348 | do { \ | |
349 | bt_field_path_put_ref(_field_path); \ | |
350 | (_field_path) = NULL; \ | |
351 | } while (0) | |
352 | ||
353 | /*! | |
354 | @brief | |
355 | Decrements the reference count of the field path \bt_p{_dst}, sets | |
356 | \bt_p{_dst} to \bt_p{_src}, and then sets \bt_p{_src} to \c NULL. | |
357 | ||
358 | This macro effectively moves a field path reference from the expression | |
359 | \bt_p{_src} to the expression \bt_p{_dst}, putting the existing | |
360 | \bt_p{_dst} reference. | |
361 | ||
362 | @param _dst | |
363 | @parblock | |
364 | Destination expression. | |
365 | ||
366 | Can contain \c NULL. | |
367 | @endparblock | |
368 | @param _src | |
369 | @parblock | |
370 | Source expression. | |
371 | ||
372 | Can contain \c NULL. | |
373 | @endparblock | |
374 | ||
375 | @bt_pre_assign_expr{_dst} | |
376 | @bt_pre_assign_expr{_src} | |
377 | */ | |
378 | #define BT_FIELD_PATH_MOVE_REF(_dst, _src) \ | |
379 | do { \ | |
380 | bt_field_path_put_ref(_dst); \ | |
381 | (_dst) = (_src); \ | |
382 | (_src) = NULL; \ | |
383 | } while (0) | |
384 | ||
385 | /*! @} */ | |
386 | ||
387 | /*! | |
388 | @name Field path item | |
389 | @{ | |
390 | ||
391 | @typedef struct bt_field_path_item bt_field_path_item; | |
392 | ||
393 | @brief | |
394 | Field path item. | |
395 | ||
396 | */ | |
397 | ||
398 | /*! | |
399 | @brief | |
400 | Field path item type enumerators. | |
401 | */ | |
402 | typedef enum bt_field_path_item_type { | |
403 | /*! | |
404 | @brief | |
405 | Index of a \bt_struct_field member or selected \bt_var_field | |
406 | option's field. | |
407 | */ | |
408 | BT_FIELD_PATH_ITEM_TYPE_INDEX = 1 << 0, | |
409 | ||
410 | /*! | |
411 | @brief | |
412 | Common field of an \bt_array_field. | |
413 | */ | |
414 | BT_FIELD_PATH_ITEM_TYPE_CURRENT_ARRAY_ELEMENT = 1 << 1, | |
415 | ||
416 | /*! | |
417 | @brief | |
418 | Current field of an \bt_opt_field. | |
419 | */ | |
420 | BT_FIELD_PATH_ITEM_TYPE_CURRENT_OPTION_CONTENT = 1 << 2, | |
421 | } bt_field_path_item_type; | |
422 | ||
423 | /*! | |
424 | @brief | |
425 | Returns the type enumerator of the field path item | |
426 | \bt_p{item}. | |
427 | ||
428 | See the \ref api-tir-field-path-prop-items "items" property. | |
429 | ||
430 | @param[in] item | |
431 | Field path item of which to get the type enumerator | |
432 | ||
433 | @returns | |
434 | Type enumerator of \bt_p{item}. | |
435 | ||
436 | @bt_pre_not_null{item} | |
437 | */ | |
438 | extern bt_field_path_item_type bt_field_path_item_get_type( | |
439 | const bt_field_path_item *item); | |
440 | ||
441 | /*! | |
442 | @brief | |
443 | Returns the index value of the index field path item | |
444 | \bt_p{item}. | |
445 | ||
446 | See the \ref api-tir-field-path-prop-items "items" property. | |
447 | ||
448 | @param[in] item | |
449 | Index field path item of which to get the index value. | |
450 | ||
451 | @returns | |
452 | Index value of \bt_p{item}. | |
453 | ||
454 | @bt_pre_not_null{item} | |
455 | @pre | |
456 | \bt_p{item} is an index field path item | |
457 | (bt_field_path_item_get_type() returns | |
458 | #BT_FIELD_PATH_ITEM_TYPE_INDEX). | |
459 | */ | |
460 | extern uint64_t bt_field_path_item_index_get_index( | |
461 | const bt_field_path_item *item); | |
462 | ||
463 | /*! @} */ | |
464 | ||
465 | /*! @} */ | |
466 | ||
467 | #ifdef __cplusplus | |
468 | } | |
469 | #endif | |
470 | ||
471 | #endif /* BABELTRACE2_TRACE_IR_FIELD_PATH_H */ |