lib: field path: have a specific item for "current array element"
[babeltrace.git] / include / babeltrace / object-internal.h
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1#ifndef BABELTRACE_OBJECT_INTERNAL_H
2#define BABELTRACE_OBJECT_INTERNAL_H
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3
4/*
e2f7325d 5 * Copyright 2017-2018 Philippe Proulx <pproulx@efficios.com>
83509119 6 * Copyright 2015 Jérémie Galarneau <jeremie.galarneau@efficios.com>
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7 *
8 * Permission is hereby granted, free of charge, to any person obtaining a copy
9 * of this software and associated documentation files (the "Software"), to deal
10 * in the Software without restriction, including without limitation the rights
11 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
12 * copies of the Software, and to permit persons to whom the Software is
13 * furnished to do so, subject to the following conditions:
14 *
15 * The above copyright notice and this permission notice shall be included in
16 * all copies or substantial portions of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
21 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
22 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
23 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
24 * SOFTWARE.
25 */
26
312c056a 27#include <babeltrace/babeltrace-internal.h>
f6ccaed9 28#include <babeltrace/assert-internal.h>
312c056a 29#include <stdbool.h>
273b65be 30
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31struct bt_object;
32
33typedef void (*bt_object_release_func)(struct bt_object *);
34typedef void (*bt_object_parent_is_owner_listener_func)(
35 struct bt_object *);
36
37static inline
398454ed 38void bt_object_get_no_null_check(const void *obj);
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39
40static inline
398454ed 41void bt_object_put_no_null_check(const void *obj);
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42
43/*
44 * Babeltrace object base.
45 *
46 * All objects publicly exposed by Babeltrace APIs must contain this
47 * object as their first member.
de3dd40e 48 */
83509119 49struct bt_object {
312c056a 50 /*
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51 * True if this object is shared, that is, it has a reference
52 * count.
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53 */
54 bool is_shared;
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55
56 /*
57 * Current reference count.
58 */
59 unsigned long long ref_count;
60
61 /*
62 * Release function called when the object's reference count
63 * falls to zero. For an object with a parent, this function is
64 * bt_object_with_parent_release_func(), which calls
65 * `spec_release_func` below if there's no current parent.
66 */
67 bt_object_release_func release_func;
68
69 /*
70 * Specific release function called by
71 * bt_object_with_parent_release_func() or directly by a
72 * parent object.
73 */
74 bt_object_release_func spec_release_func;
75
76 /*
77 * Optional callback for an object with a parent, called by
78 * bt_object_with_parent_release_func() to indicate to the
79 * object that its parent is its owner.
80 */
81 bt_object_parent_is_owner_listener_func
82 parent_is_owner_listener_func;
83
84 /*
85 * Optional parent object.
86 */
87 struct bt_object *parent;
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88};
89
90static inline
398454ed 91unsigned long long bt_object_get_ref_count(const struct bt_object *c_obj)
7c56f3cc 92{
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93 struct bt_object *obj = (void *) c_obj;
94
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95 BT_ASSERT(obj);
96 BT_ASSERT(obj->is_shared);
97 return obj->ref_count;
98}
5d2d9981 99
3fea54f6 100static inline
398454ed 101struct bt_object *bt_object_borrow_parent(const struct bt_object *c_obj)
3fea54f6 102{
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103 struct bt_object *obj = (void *) c_obj;
104
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105 BT_ASSERT(obj);
106 BT_ASSERT(obj->is_shared);
107 return obj->parent;
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108}
109
110static inline
398454ed 111struct bt_object *bt_object_get_parent(const struct bt_object *c_obj)
5d2d9981 112{
398454ed 113 struct bt_object *obj = (void *) c_obj;
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114 struct bt_object *parent = bt_object_borrow_parent(obj);
115
116 if (parent) {
117 bt_object_get_no_null_check(parent);
118 }
119
120 return parent;
121}
122
123static inline
124void bt_object_set_parent(struct bt_object *child, struct bt_object *parent)
125{
126 BT_ASSERT(child);
127 BT_ASSERT(child->is_shared);
5d2d9981 128
0f5e83e5 129#ifdef BT_LOGV
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130 BT_LOGV("Setting object's parent: addr=%p, parent-addr=%p",
131 child, parent);
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132#endif
133
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134 /*
135 * It is assumed that a "child" having a parent is publicly
136 * reachable. Therefore, a reference to its parent must be
137 * taken. The reference to the parent will be released once the
138 * object's reference count falls to zero.
139 */
140 if (parent) {
141 BT_ASSERT(!child->parent);
142 child->parent = parent;
143 bt_object_get_no_null_check(parent);
144 } else {
145 if (child->parent) {
146 bt_object_put_no_null_check(child->parent);
147 }
148
149 child->parent = NULL;
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150 }
151}
152
7c56f3cc 153static inline
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154void bt_object_try_spec_release(struct bt_object *obj)
155{
156 BT_ASSERT(obj);
157 BT_ASSERT(obj->is_shared);
158 BT_ASSERT(obj->spec_release_func);
159
160 if (bt_object_get_ref_count(obj) == 0) {
161 obj->spec_release_func(obj);
162 }
163}
164
165static inline
166void bt_object_with_parent_release_func(struct bt_object *obj)
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167{
168 if (obj->parent) {
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169 /*
170 * Keep our own copy of the parent address because `obj`
171 * could be destroyed in
172 * obj->parent_is_owner_listener_func().
173 */
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174 struct bt_object *parent = obj->parent;
175
176#ifdef BT_LOGV
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177 BT_LOGV("Releasing parented object: addr=%p, ref-count=%llu, "
178 "parent-addr=%p, parent-ref-count=%llu",
179 obj, obj->ref_count,
180 parent, parent->ref_count);
0f5e83e5 181#endif
f167d3c0 182
3fea54f6 183 if (obj->parent_is_owner_listener_func) {
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184 /*
185 * Object has a chance to destroy itself here
186 * under certain conditions and notify its
187 * parent. At this point the parent is
188 * guaranteed to exist because it's not put yet.
189 */
3fea54f6 190 obj->parent_is_owner_listener_func(obj);
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191 }
192
5d2d9981 193 /* The release function will be invoked by the parent. */
3fea54f6 194 bt_object_put_no_null_check(parent);
5d2d9981 195 } else {
3fea54f6 196 bt_object_try_spec_release(obj);
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197 }
198}
199
200static inline
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201void bt_object_init(struct bt_object *obj, bool is_shared,
202 bt_object_release_func release_func)
5d2d9981 203{
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204 BT_ASSERT(obj);
205 BT_ASSERT(!is_shared || release_func);
206 obj->is_shared = is_shared;
207 obj->release_func = release_func;
208 obj->parent_is_owner_listener_func = NULL;
209 obj->spec_release_func = NULL;
210 obj->parent = NULL;
211 obj->ref_count = 1;
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212}
213
214static inline
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215void bt_object_init_shared(struct bt_object *obj,
216 bt_object_release_func release_func)
dc3fffef 217{
3fea54f6 218 bt_object_init(obj, true, release_func);
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219}
220
221static inline
3fea54f6 222void bt_object_init_unique(struct bt_object *obj)
273b65be 223{
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224 bt_object_init(obj, false, NULL);
225}
5d2d9981 226
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227static inline
228void bt_object_init_shared_with_parent(struct bt_object *obj,
229 bt_object_release_func spec_release_func)
230{
231 BT_ASSERT(obj);
232 BT_ASSERT(spec_release_func);
233 bt_object_init_shared(obj, bt_object_with_parent_release_func);
234 obj->spec_release_func = spec_release_func;
235}
0f5e83e5 236
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237static inline
238void bt_object_set_parent_is_owner_listener_func(struct bt_object *obj,
239 bt_object_parent_is_owner_listener_func func)
240{
241 BT_ASSERT(obj);
242 BT_ASSERT(obj->is_shared);
243 BT_ASSERT(obj->spec_release_func);
244 ((struct bt_object *) obj)->parent_is_owner_listener_func = func;
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245}
246
312c056a 247static inline
398454ed 248void bt_object_inc_ref_count(const struct bt_object *c_obj)
312c056a 249{
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250 struct bt_object *obj = (void *) c_obj;
251
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252 BT_ASSERT(obj);
253 BT_ASSERT(obj->is_shared);
254 obj->ref_count++;
255 BT_ASSERT(obj->ref_count != 0);
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256}
257
6c677fb5 258static inline
398454ed 259void bt_object_get_no_null_check_no_parent_check(const struct bt_object *c_obj)
6c677fb5 260{
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261 struct bt_object *obj = (void *) c_obj;
262
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263 BT_ASSERT(obj);
264 BT_ASSERT(obj->is_shared);
265
266#ifdef BT_LOGV
267 BT_LOGV("Incrementing object's reference count: %llu -> %llu: "
268 "addr=%p, cur-count=%llu, new-count=%llu",
269 obj->ref_count, obj->ref_count + 1,
270 obj, obj->ref_count, obj->ref_count + 1);
271#endif
272
273 bt_object_inc_ref_count(obj);
274}
275
5d2d9981 276static inline
398454ed 277void bt_object_get_no_null_check(const void *c_obj)
5d2d9981 278{
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279 struct bt_object *obj = (void *) c_obj;
280
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281 BT_ASSERT(obj);
282 BT_ASSERT(obj->is_shared);
5d2d9981 283
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284 if (unlikely(obj->parent && bt_object_get_ref_count(obj) == 0)) {
285#ifdef BT_LOGV
286 BT_LOGV("Incrementing object's parent's reference count: "
287 "addr=%p, parent-addr=%p", obj, obj->parent);
288#endif
289
290 bt_object_get_no_null_check(obj->parent);
291 }
292
293#ifdef BT_LOGV
294 BT_LOGV("Incrementing object's reference count: %llu -> %llu: "
295 "addr=%p, cur-count=%llu, new-count=%llu",
296 obj->ref_count, obj->ref_count + 1,
297 obj, obj->ref_count, obj->ref_count + 1);
298#endif
299
300 bt_object_inc_ref_count(obj);
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301}
302
f167d3c0 303static inline
398454ed 304void bt_object_put_no_null_check(const void *c_obj)
f167d3c0 305{
398454ed
PP
306 struct bt_object *obj = (void *) c_obj;
307
f6ccaed9 308 BT_ASSERT(obj);
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309 BT_ASSERT(obj->is_shared);
310 BT_ASSERT(obj->ref_count > 0);
311
312#ifdef BT_LOGV
313 BT_LOGV("Decrementing object's reference count: %llu -> %llu: "
314 "addr=%p, cur-count=%llu, new-count=%llu",
315 obj->ref_count, obj->ref_count - 1,
316 obj, obj->ref_count, obj->ref_count - 1);
317#endif
318
319 obj->ref_count--;
320
321 if (obj->ref_count == 0) {
322 BT_ASSERT(obj->release_func);
323 obj->release_func(obj);
324 }
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325}
326
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327static inline
328void bt_object_get_ref(const void *ptr)
329{
330 struct bt_object *obj = (void *) ptr;
331
332 if (unlikely(!obj)) {
333 return;
334 }
335
336#ifdef BT_ASSERT_PRE
337 BT_ASSERT_PRE(obj->is_shared, "Object is not shared: %!+O", obj);
338#endif
339
340 bt_object_get_no_null_check(obj);
341}
342
343static inline
344void bt_object_put_ref(const void *ptr)
345{
346 struct bt_object *obj = (void *) ptr;
347
348 if (unlikely(!obj)) {
349 return;
350 }
351
352#ifdef BT_ASSERT_PRE
353 BT_ASSERT_PRE(obj->is_shared, "Object is not shared: %!+O", obj);
354 BT_ASSERT_PRE(bt_object_get_ref_count(obj) > 0,
355 "Decrementing a reference count set to 0: %!+O", ptr);
356#endif
357
358 bt_object_put_no_null_check(obj);
359}
360
361#define BT_OBJECT_PUT_REF_AND_RESET(_var) \
362 do { \
363 bt_object_put_ref(_var); \
364 (_var) = NULL; \
365 } while (0)
366
367#define BT_OBJECT_MOVE_REF(_var_dst, _var_src) \
368 do { \
369 bt_object_put_ref(_var_dst); \
370 (_var_dst) = (_var_src); \
371 (_var_src) = NULL; \
372 } while (0)
373
83509119 374#endif /* BABELTRACE_OBJECT_INTERNAL_H */
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