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b70d57a1 | 1 | /* |
0235b0db | 2 | * SPDX-License-Identifier: MIT |
b70d57a1 | 3 | * |
0235b0db | 4 | * Copyright (C) 2010-2019 EfficiOS Inc. and Linux Foundation |
b70d57a1 PP |
5 | */ |
6 | ||
0235b0db MJ |
7 | #ifndef BABELTRACE2_GRAPH_INTERRUPTER_H |
8 | #define BABELTRACE2_GRAPH_INTERRUPTER_H | |
9 | ||
b70d57a1 PP |
10 | #ifndef __BT_IN_BABELTRACE_H |
11 | # error "Please include <babeltrace2/babeltrace.h> instead." | |
12 | #endif | |
13 | ||
14 | #include <babeltrace2/types.h> | |
15 | ||
16 | #ifdef __cplusplus | |
17 | extern "C" { | |
18 | #endif | |
19 | ||
43c59509 PP |
20 | /*! |
21 | @defgroup api-intr Interrupter | |
22 | @ingroup api-graph | |
23 | ||
24 | @brief | |
25 | Interrupter. | |
26 | ||
27 | An <strong><em>interrupter</em></strong> is a simple object which has | |
28 | a single boolean state: set or not set. | |
29 | ||
30 | You can use an interrupter to interrupt a running trace processing | |
31 | \bt_graph or \ref api-qexec "query". The user and library functions periodically | |
32 | check if they are interrupted (with | |
33 | bt_self_component_sink_is_interrupted(), | |
34 | bt_self_message_iterator_is_interrupted(), or | |
35 | bt_query_executor_is_interrupted()); meanwhile, another thread or | |
36 | a signal handler sets the shared interrupter with bt_interrupter_set(). | |
37 | ||
38 | To interrupt a running trace processing graph or query: | |
39 | ||
40 | -# Create an interrupter with bt_interrupter_create(). | |
41 | ||
42 | -# Before running a trace processing graph with bt_graph_run() or | |
43 | performing a query with bt_query_executor_query(), add | |
44 | the created interrupter to the object with bt_graph_add_interrupter() | |
45 | or bt_query_executor_add_interrupter(). | |
46 | ||
47 | Alternatively, you can borrow the existing, default interrupter from | |
48 | those objects with bt_graph_borrow_default_interrupter() and | |
49 | bt_query_executor_borrow_default_interrupter(). | |
50 | ||
51 | -# Run the graph with bt_graph_run() or perform the query with | |
52 | bt_query_executor_query(). | |
53 | ||
54 | -# From a signal handler or another thread, call bt_interrupter_set() to | |
55 | set the shared interrupter. | |
56 | ||
57 | Eventually, the trace processing graph or query thread checks if it's | |
58 | interrupted and stops processing, usually returning a status code which | |
59 | ends with \c _AGAIN. | |
60 | ||
61 | You can add more than one interrupter to a trace processing graph and | |
62 | to a query executor. The bt_self_component_sink_is_interrupted(), | |
63 | bt_self_message_iterator_is_interrupted(), and | |
64 | bt_query_executor_is_interrupted() functions return the logical | |
65 | disjunction of all the added interrupters's states, so that \em any | |
66 | interrupter can interrupt the thread. | |
67 | ||
68 | Once a trace processing graph or a query executor is interrupted and | |
69 | you get the thread's control back, you can reset the interrupter | |
70 | with bt_interrupter_reset() and continue the previous operation, | |
71 | calling bt_graph_run() or bt_query_executor_query() again. | |
72 | ||
73 | An interrupter is a \ref api-fund-shared-object "shared object": get a | |
74 | new reference with bt_interrupter_get_ref() and put an existing | |
75 | reference with bt_interrupter_put_ref(). | |
76 | ||
77 | The type of an interrupter is #bt_interrupter. | |
78 | */ | |
79 | ||
80 | /*! @{ */ | |
81 | ||
82 | /*! | |
83 | @name Type | |
84 | @{ | |
85 | ||
86 | @typedef struct bt_interrupter bt_interrupter; | |
87 | ||
88 | @brief | |
89 | Interrupter. | |
90 | ||
91 | @} | |
92 | */ | |
93 | ||
94 | /*! | |
95 | @name Creation | |
96 | @{ | |
97 | */ | |
98 | ||
99 | /*! | |
100 | @brief | |
101 | Creates a default interrupter. | |
102 | ||
103 | On success, the returned interrupter is \em not set | |
104 | (bt_interrupter_is_set() returns #BT_FALSE). | |
105 | ||
106 | @returns | |
107 | New interrupter reference, or \c NULL on memory error. | |
108 | */ | |
b70d57a1 PP |
109 | extern bt_interrupter *bt_interrupter_create(void); |
110 | ||
43c59509 PP |
111 | /*! @} */ |
112 | ||
113 | /*! | |
114 | @name State | |
115 | @{ | |
116 | */ | |
117 | ||
118 | /*! | |
119 | @brief | |
120 | Sets the interrupter \bt_p{interrupter}. | |
121 | ||
122 | After you call this function, bt_interrupter_is_set() returns | |
123 | #BT_TRUE. | |
124 | ||
125 | @param[in] interrupter | |
126 | Interrupter to set. | |
127 | ||
128 | @bt_pre_not_null{interrupter} | |
129 | ||
130 | @sa bt_interrupter_reset() — | |
131 | Resets an interrupter. | |
132 | @sa bt_interrupter_is_set() — | |
133 | Returns whether or not an interrupter is set. | |
134 | */ | |
b70d57a1 PP |
135 | extern void bt_interrupter_set(bt_interrupter *interrupter); |
136 | ||
43c59509 PP |
137 | /*! |
138 | @brief | |
139 | Resets the interrupter \bt_p{interrupter}. | |
140 | ||
141 | After you call this function, bt_interrupter_is_set() returns | |
142 | #BT_FALSE. | |
143 | ||
144 | @param[in] interrupter | |
145 | Interrupter to reset. | |
146 | ||
147 | @bt_pre_not_null{interrupter} | |
148 | ||
149 | @sa bt_interrupter_set() — | |
150 | Sets an interrupter. | |
151 | @sa bt_interrupter_is_set() — | |
152 | Returns whether or not an interrupter is set. | |
153 | */ | |
b70d57a1 PP |
154 | extern void bt_interrupter_reset(bt_interrupter *interrupter); |
155 | ||
43c59509 PP |
156 | /*! |
157 | @brief | |
158 | Returns whether or not the interrupter \bt_p{interrupter} is set. | |
159 | ||
160 | @param[in] interrupter | |
161 | Interrupter to reset. | |
162 | ||
163 | @returns | |
164 | #BT_TRUE if \bt_p{interrupter} is set. | |
165 | ||
166 | @bt_pre_not_null{interrupter} | |
167 | ||
168 | @sa bt_interrupter_set() — | |
169 | Sets an interrupter. | |
170 | @sa bt_interrupter_reset() — | |
171 | Resets an interrupter. | |
172 | */ | |
173 | extern bt_bool bt_interrupter_is_set(const bt_interrupter *interrupter); | |
174 | ||
175 | /*! @} */ | |
176 | ||
177 | /*! | |
178 | @name Reference count | |
179 | @{ | |
180 | */ | |
181 | ||
182 | /*! | |
183 | @brief | |
184 | Increments the \ref api-fund-shared-object "reference count" of | |
185 | the interrupter \bt_p{interrupter}. | |
186 | ||
187 | @param[in] interrupter | |
188 | @parblock | |
189 | Interrupter of which to increment the reference count. | |
190 | ||
191 | Can be \c NULL. | |
192 | @endparblock | |
193 | ||
194 | @sa bt_interrupter_put_ref() — | |
195 | Decrements the reference count of an interrupter. | |
196 | */ | |
197 | extern void bt_interrupter_get_ref(const bt_interrupter *interrupter); | |
198 | ||
199 | /*! | |
200 | @brief | |
201 | Decrements the \ref api-fund-shared-object "reference count" of | |
202 | the interrupter \bt_p{interrupter}. | |
203 | ||
204 | @param[in] interrupter | |
205 | @parblock | |
206 | Interrupter of which to decrement the reference count. | |
207 | ||
208 | Can be \c NULL. | |
209 | @endparblock | |
210 | ||
211 | @sa bt_interrupter_get_ref() — | |
212 | Increments the reference count of an interrupter. | |
213 | */ | |
214 | extern void bt_interrupter_put_ref(const bt_interrupter *interrupter); | |
215 | ||
216 | /*! | |
217 | @brief | |
218 | Decrements the reference count of the interrupter | |
219 | \bt_p{_interrupter}, and then sets \bt_p{_interrupter} to \c NULL. | |
220 | ||
221 | @param _interrupter | |
222 | @parblock | |
223 | Interrupter of which to decrement the reference count. | |
224 | ||
225 | Can contain \c NULL. | |
226 | @endparblock | |
227 | ||
228 | @bt_pre_assign_expr{_interrupter} | |
229 | */ | |
230 | #define BT_INTERRUPTER_PUT_REF_AND_RESET(_interrupter) \ | |
231 | do { \ | |
232 | bt_interrupter_put_ref(_interrupter); \ | |
233 | (_interrupter) = NULL; \ | |
234 | } while (0) | |
235 | ||
236 | /*! | |
237 | @brief | |
238 | Decrements the reference count of the interrupter \bt_p{_dst}, sets | |
239 | \bt_p{_dst} to \bt_p{_src}, and then sets \bt_p{_src} to \c NULL. | |
240 | ||
241 | This macro effectively moves an interrupter reference from the | |
242 | expression \bt_p{_src} to the expression \bt_p{_dst}, putting the | |
243 | existing \bt_p{_dst} reference. | |
244 | ||
245 | @param _dst | |
246 | @parblock | |
247 | Destination expression. | |
248 | ||
249 | Can contain \c NULL. | |
250 | @endparblock | |
251 | @param _src | |
252 | @parblock | |
253 | Source expression. | |
254 | ||
255 | Can contain \c NULL. | |
256 | @endparblock | |
257 | ||
258 | @bt_pre_assign_expr{_dst} | |
259 | @bt_pre_assign_expr{_src} | |
260 | */ | |
261 | #define BT_INTERRUPTER_MOVE_REF(_dst, _src) \ | |
262 | do { \ | |
263 | bt_interrupter_put_ref(_dst); \ | |
264 | (_dst) = (_src); \ | |
265 | (_src) = NULL; \ | |
266 | } while (0) | |
267 | ||
268 | /*! @} */ | |
269 | ||
270 | /*! @} */ | |
271 | ||
b70d57a1 PP |
272 | #ifdef __cplusplus |
273 | } | |
274 | #endif | |
275 | ||
276 | #endif /* BABELTRACE2_GRAPH_INTERRUPTER_H */ |