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43c59509 | 1 | /* |
0235b0db | 2 | * SPDX-License-Identifier: MIT |
43c59509 | 3 | * |
0235b0db | 4 | * Copyright (C) 2010-2019 EfficiOS Inc. and Linux Foundation |
43c59509 PP |
5 | */ |
6 | ||
0235b0db MJ |
7 | #ifndef BABELTRACE2_TRACE_IR_FIELD_PATH_H |
8 | #define BABELTRACE2_TRACE_IR_FIELD_PATH_H | |
9 | ||
43c59509 PP |
10 | #ifndef __BT_IN_BABELTRACE_H |
11 | # error "Please include <babeltrace2/babeltrace.h> instead." | |
12 | #endif | |
13 | ||
14 | #include <stdint.h> | |
15 | ||
16 | #include <babeltrace2/types.h> | |
17 | ||
18 | #ifdef __cplusplus | |
19 | extern "C" { | |
20 | #endif | |
21 | ||
22 | /*! | |
23 | @defgroup api-tir-field-path Field path | |
24 | @ingroup api-tir | |
25 | ||
26 | @brief | |
27 | Path to a \bt_field. | |
28 | ||
29 | A <strong><em>field path</em></strong> indicates how to reach a given | |
30 | \bt_field from a given <em>root scope</em>. | |
31 | ||
32 | More specifically, a field path indicates how to reach: | |
33 | ||
34 | - The length field of a \bt_darray_field (with a length field). | |
35 | - The selector field of a \bt_opt_field (with a selector field). | |
36 | - The selector field of a \bt_var_field (with a selector field). | |
37 | ||
38 | You can borrow the field path from the \ref api-tir-fc "classes" of such | |
39 | fields with | |
40 | bt_field_class_array_dynamic_with_length_field_borrow_length_field_path_const(), | |
41 | bt_field_class_option_with_selector_field_borrow_selector_field_path_const(), | |
42 | and | |
43 | bt_field_class_variant_with_selector_field_borrow_selector_field_path_const(). | |
44 | Note that the field path properties of those field classes only becomes | |
45 | available when the field class becomes part of an \bt_ev_cls or of a | |
46 | \bt_stream_cls. See | |
47 | \ref api-tir-fc-link "Field classes with links to other field classes". | |
48 | ||
49 | A field path is a \ref api-tir "trace IR" metadata object. | |
50 | ||
51 | A field path is a \ref api-fund-shared-object "shared object": get a | |
52 | new reference with bt_field_path_get_ref() and put an existing | |
53 | reference with bt_field_path_put_ref(). | |
54 | ||
55 | The type of a field path is #bt_field_path. | |
56 | ||
57 | <h1>Properties</h1> | |
58 | ||
59 | A field path has the following properties: | |
60 | ||
61 | <dl> | |
62 | <dt> | |
63 | \anchor api-tir-field-path-prop-root | |
64 | Root scope | |
65 | </dt> | |
66 | <dd> | |
67 | Indicates from which \bt_struct_field to start a lookup. | |
68 | ||
69 | See \ref api-tir-field-path-lookup-algo "Lookup algorithm" to | |
70 | learn more. | |
71 | ||
72 | Get a field path's root scope with bt_field_path_get_root_scope(). | |
73 | </dd> | |
74 | ||
75 | <dt> | |
76 | \anchor api-tir-field-path-prop-items | |
77 | Items | |
78 | </dt> | |
79 | <dd> | |
80 | Each item in a field path's item list indicates which action to take | |
81 | to follow the path to the linked \bt_field. | |
82 | ||
83 | See \ref api-tir-field-path-lookup-algo "Lookup algorithm" to | |
84 | learn more. | |
85 | ||
86 | Get the number of items in a field path with | |
87 | bt_field_path_get_item_count(). | |
88 | ||
89 | Borrow an item from a field path with | |
90 | bt_field_path_borrow_item_by_index_const(). This function | |
91 | returns the #bt_field_path_item type. | |
92 | ||
93 | A field path item is a \ref api-fund-unique-object "unique object": | |
94 | it belongs to the field path which contains it. | |
95 | </dd> | |
96 | </dl> | |
97 | ||
98 | <h1>\anchor api-tir-field-path-lookup-algo Lookup algorithm</h1> | |
99 | ||
100 | The field resolution algorithm using a field path is: | |
101 | ||
102 | -# Use the appropriate function to set a <em>current field</em> variable | |
103 | from the root scope (as returned by bt_field_path_get_root_scope()): | |
104 | ||
105 | <dl> | |
106 | <dt>#BT_FIELD_PATH_SCOPE_PACKET_CONTEXT</dt> | |
107 | <dd> | |
108 | bt_packet_borrow_context_field_const(). | |
109 | </dd> | |
110 | <dt>#BT_FIELD_PATH_SCOPE_EVENT_COMMON_CONTEXT</dt> | |
111 | <dd> | |
112 | bt_event_borrow_common_context_field_const(). | |
113 | </dd> | |
114 | <dt>#BT_FIELD_PATH_SCOPE_EVENT_SPECIFIC_CONTEXT</dt> | |
115 | <dd> | |
116 | bt_event_borrow_specific_context_field_const(). | |
117 | </dd> | |
118 | <dt>#BT_FIELD_PATH_SCOPE_EVENT_PAYLOAD</dt> | |
119 | <dd> | |
120 | bt_event_borrow_payload_field_const(). | |
121 | </dd> | |
122 | </dl> | |
123 | ||
124 | -# For each field path item (use bt_field_path_get_item_count() | |
125 | and bt_field_path_borrow_item_by_index_const()), depending on | |
126 | the item's type (as returned by bt_field_path_item_get_type()): | |
127 | ||
128 | <dl> | |
129 | <dt>#BT_FIELD_PATH_ITEM_TYPE_INDEX</dt> | |
130 | <dd> | |
131 | Call bt_field_path_item_index_get_index() to get the item's | |
132 | index value. | |
133 | ||
134 | Depending on the current field's class's type (as | |
135 | returned by bt_field_get_class_type()): | |
136 | ||
137 | <dl> | |
138 | <dt>\bt_c_struct_fc</dt> | |
139 | <dd> | |
140 | Call bt_field_structure_borrow_member_field_by_index_const() | |
141 | with the current field and with the item's index to set the | |
142 | new current field. | |
143 | </dd> | |
144 | ||
145 | <dt>\bt_c_var_fc</dt> | |
146 | <dd> | |
147 | Call bt_field_variant_borrow_selected_option_field_const() | |
148 | with the current field to set the new current field. | |
149 | </dd> | |
150 | </dl> | |
151 | </dd> | |
152 | ||
153 | <dt>#BT_FIELD_PATH_ITEM_TYPE_CURRENT_ARRAY_ELEMENT</dt> | |
154 | <dd> | |
155 | Call bt_field_array_borrow_element_field_by_index_const() | |
156 | with the index of the field eventually containing the | |
157 | field with a link (\bt_darray_field, \bt_opt_field, or | |
158 | \bt_var_field) and the current field to set the new current | |
159 | field. | |
160 | </dd> | |
161 | ||
162 | <dt>#BT_FIELD_PATH_ITEM_TYPE_CURRENT_OPTION_CONTENT</dt> | |
163 | <dd> | |
164 | Call bt_field_option_borrow_field_const() with the current | |
165 | field to set the new current field. | |
166 | </dd> | |
167 | </dl> | |
168 | ||
169 | After applying this procedure, the current field is the linked | |
170 | field. | |
171 | */ | |
172 | ||
173 | /*! @{ */ | |
174 | ||
175 | /*! | |
176 | @name Field path | |
177 | @{ | |
178 | ||
179 | @typedef struct bt_field_path bt_field_path; | |
180 | ||
181 | @brief | |
182 | Field path. | |
183 | ||
184 | */ | |
185 | ||
186 | /*! | |
187 | @brief | |
188 | Field path scopes. | |
189 | */ | |
190 | typedef enum bt_field_path_scope { | |
191 | /*! | |
192 | @brief | |
193 | Packet context. | |
194 | */ | |
195 | BT_FIELD_PATH_SCOPE_PACKET_CONTEXT = 0, | |
196 | ||
197 | /*! | |
198 | @brief | |
199 | Event common context. | |
200 | */ | |
201 | BT_FIELD_PATH_SCOPE_EVENT_COMMON_CONTEXT = 1, | |
202 | ||
203 | /*! | |
204 | @brief | |
205 | Event specific context. | |
206 | */ | |
207 | BT_FIELD_PATH_SCOPE_EVENT_SPECIFIC_CONTEXT = 2, | |
208 | ||
209 | /*! | |
210 | @brief | |
211 | Event payload. | |
212 | */ | |
213 | BT_FIELD_PATH_SCOPE_EVENT_PAYLOAD = 3, | |
214 | } bt_field_path_scope; | |
215 | ||
216 | /*! | |
217 | @brief | |
218 | Returns the root scope of the field path \bt_p{field_path}. | |
219 | ||
220 | See the \ref api-tir-field-path-prop-root "root scope" property. | |
221 | ||
222 | @param[in] field_path | |
223 | Field path of which to get the root scope. | |
224 | ||
225 | @returns | |
226 | Root scope of \bt_p{field_path}. | |
227 | ||
228 | @bt_pre_not_null{field_path} | |
229 | */ | |
230 | extern bt_field_path_scope bt_field_path_get_root_scope( | |
231 | const bt_field_path *field_path); | |
232 | ||
233 | /*! | |
234 | @brief | |
235 | Returns the number of items contained in the field path | |
236 | \bt_p{field_path}. | |
237 | ||
238 | See the \ref api-tir-field-path-prop-items "items" property. | |
239 | ||
240 | @param[in] field_path | |
241 | Field path of which to get the number of contained items. | |
242 | ||
243 | @returns | |
244 | Number of contained items in \bt_p{field_path}. | |
245 | ||
246 | @bt_pre_not_null{field_path} | |
247 | */ | |
248 | extern uint64_t bt_field_path_get_item_count( | |
249 | const bt_field_path *field_path); | |
250 | ||
251 | /*! | |
252 | @brief | |
253 | Borrows the item at index \bt_p{index} from the | |
254 | field path \bt_p{field_path}. | |
255 | ||
256 | See the \ref api-tir-field-path-prop-items "items" property. | |
257 | ||
258 | @param[in] field_path | |
259 | Field path from which to borrow the item at index \bt_p{index}. | |
260 | @param[in] index | |
261 | Index of the item to borrow from \bt_p{field_path}. | |
262 | ||
263 | @returns | |
264 | @parblock | |
265 | \em Borrowed reference of the item of | |
266 | \bt_p{field_path} at index \bt_p{index}. | |
267 | ||
268 | The returned pointer remains valid as long as \bt_p{field_path} | |
269 | exists. | |
270 | @endparblock | |
271 | ||
272 | @bt_pre_not_null{field_path} | |
273 | @pre | |
274 | \bt_p{index} is less than the number of items in | |
275 | \bt_p{field_path} (as returned by bt_field_path_get_item_count()). | |
276 | ||
277 | @sa bt_field_path_get_item_count() — | |
278 | Returns the number of items contained in a field path. | |
279 | */ | |
280 | extern const bt_field_path_item *bt_field_path_borrow_item_by_index_const( | |
281 | const bt_field_path *field_path, uint64_t index); | |
282 | ||
283 | /*! | |
284 | @brief | |
285 | Increments the \ref api-fund-shared-object "reference count" of | |
286 | the field path \bt_p{field_path}. | |
287 | ||
288 | @param[in] field_path | |
289 | @parblock | |
290 | Field path of which to increment the reference count. | |
291 | ||
292 | Can be \c NULL. | |
293 | @endparblock | |
294 | ||
295 | @sa bt_field_path_put_ref() — | |
296 | Decrements the reference count of a field path. | |
297 | */ | |
298 | extern void bt_field_path_get_ref(const bt_field_path *field_path); | |
299 | ||
300 | /*! | |
301 | @brief | |
302 | Decrements the \ref api-fund-shared-object "reference count" of | |
303 | the field path \bt_p{field_path}. | |
304 | ||
305 | @param[in] field_path | |
306 | @parblock | |
307 | Field path of which to decrement the reference count. | |
308 | ||
309 | Can be \c NULL. | |
310 | @endparblock | |
311 | ||
312 | @sa bt_field_path_get_ref() — | |
313 | Increments the reference count of a field path. | |
314 | */ | |
315 | extern void bt_field_path_put_ref(const bt_field_path *field_path); | |
316 | ||
317 | /*! | |
318 | @brief | |
319 | Decrements the reference count of the field path | |
320 | \bt_p{_field_path}, and then sets \bt_p{_field_path} to \c NULL. | |
321 | ||
322 | @param _field_path | |
323 | @parblock | |
324 | Field path of which to decrement the reference count. | |
325 | ||
326 | Can contain \c NULL. | |
327 | @endparblock | |
328 | ||
329 | @bt_pre_assign_expr{_field_path} | |
330 | */ | |
331 | #define BT_FIELD_PATH_PUT_REF_AND_RESET(_field_path) \ | |
332 | do { \ | |
333 | bt_field_path_put_ref(_field_path); \ | |
334 | (_field_path) = NULL; \ | |
335 | } while (0) | |
336 | ||
337 | /*! | |
338 | @brief | |
339 | Decrements the reference count of the field path \bt_p{_dst}, sets | |
340 | \bt_p{_dst} to \bt_p{_src}, and then sets \bt_p{_src} to \c NULL. | |
341 | ||
342 | This macro effectively moves a field path reference from the expression | |
343 | \bt_p{_src} to the expression \bt_p{_dst}, putting the existing | |
344 | \bt_p{_dst} reference. | |
345 | ||
346 | @param _dst | |
347 | @parblock | |
348 | Destination expression. | |
349 | ||
350 | Can contain \c NULL. | |
351 | @endparblock | |
352 | @param _src | |
353 | @parblock | |
354 | Source expression. | |
355 | ||
356 | Can contain \c NULL. | |
357 | @endparblock | |
358 | ||
359 | @bt_pre_assign_expr{_dst} | |
360 | @bt_pre_assign_expr{_src} | |
361 | */ | |
362 | #define BT_FIELD_PATH_MOVE_REF(_dst, _src) \ | |
363 | do { \ | |
364 | bt_field_path_put_ref(_dst); \ | |
365 | (_dst) = (_src); \ | |
366 | (_src) = NULL; \ | |
367 | } while (0) | |
368 | ||
369 | /*! @} */ | |
370 | ||
371 | /*! | |
372 | @name Field path item | |
373 | @{ | |
374 | ||
375 | @typedef struct bt_field_path_item bt_field_path_item; | |
376 | ||
377 | @brief | |
378 | Field path item. | |
379 | ||
380 | */ | |
381 | ||
382 | /*! | |
383 | @brief | |
384 | Field path item type enumerators. | |
385 | */ | |
386 | typedef enum bt_field_path_item_type { | |
387 | /*! | |
388 | @brief | |
389 | Index of a \bt_struct_field member or selected \bt_var_field | |
390 | option's field. | |
391 | */ | |
392 | BT_FIELD_PATH_ITEM_TYPE_INDEX = 1 << 0, | |
393 | ||
394 | /*! | |
395 | @brief | |
396 | Common field of an \bt_array_field. | |
397 | */ | |
398 | BT_FIELD_PATH_ITEM_TYPE_CURRENT_ARRAY_ELEMENT = 1 << 1, | |
399 | ||
400 | /*! | |
401 | @brief | |
402 | Current field of an \bt_opt_field. | |
403 | */ | |
404 | BT_FIELD_PATH_ITEM_TYPE_CURRENT_OPTION_CONTENT = 1 << 2, | |
405 | } bt_field_path_item_type; | |
406 | ||
407 | /*! | |
408 | @brief | |
409 | Returns the type enumerator of the field path item | |
410 | \bt_p{item}. | |
411 | ||
412 | See the \ref api-tir-field-path-prop-items "items" property. | |
413 | ||
414 | @param[in] item | |
415 | Field path item of which to get the type enumerator | |
416 | ||
417 | @returns | |
418 | Type enumerator of \bt_p{item}. | |
419 | ||
420 | @bt_pre_not_null{item} | |
421 | */ | |
422 | extern bt_field_path_item_type bt_field_path_item_get_type( | |
423 | const bt_field_path_item *item); | |
424 | ||
425 | /*! | |
426 | @brief | |
427 | Returns the index value of the index field path item | |
428 | \bt_p{item}. | |
429 | ||
430 | See the \ref api-tir-field-path-prop-items "items" property. | |
431 | ||
432 | @param[in] item | |
433 | Index field path item of which to get the index value. | |
434 | ||
435 | @returns | |
436 | Index value of \bt_p{item}. | |
437 | ||
438 | @bt_pre_not_null{item} | |
439 | @pre | |
440 | \bt_p{item} is an index field path item | |
441 | (bt_field_path_item_get_type() returns | |
442 | #BT_FIELD_PATH_ITEM_TYPE_INDEX). | |
443 | */ | |
444 | extern uint64_t bt_field_path_item_index_get_index( | |
445 | const bt_field_path_item *item); | |
446 | ||
447 | /*! @} */ | |
448 | ||
449 | /*! @} */ | |
450 | ||
451 | #ifdef __cplusplus | |
452 | } | |
453 | #endif | |
454 | ||
455 | #endif /* BABELTRACE2_TRACE_IR_FIELD_PATH_H */ |