Clean-up: sessiond: cmd_enable_channel_internal
[lttng-tools.git] / src / common / dynamic-array.h
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2c5ff4e4 1/*
ab5be9fa 2 * Copyright (C) 2019 Jérémie Galarneau <jeremie.galarneau@efficios.com>
2c5ff4e4 3 *
ab5be9fa 4 * SPDX-License-Identifier: LGPL-2.1-only
2c5ff4e4 5 *
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6 */
7
8#ifndef LTTNG_DYNAMIC_ARRAY_H
9#define LTTNG_DYNAMIC_ARRAY_H
10
11#include <common/dynamic-buffer.h>
2c5ff4e4 12
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13typedef void (*lttng_dynamic_array_element_destructor)(void *element);
14typedef void (*lttng_dynamic_pointer_array_destructor)(void *ptr);
15
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16struct lttng_dynamic_array {
17 struct lttng_dynamic_buffer buffer;
18 size_t element_size;
19 size_t size;
93bed9fe 20 lttng_dynamic_array_element_destructor destructor;
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21};
22
23struct lttng_dynamic_pointer_array {
24 struct lttng_dynamic_array array;
25};
26
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27/*
28 * Initialize a resizable array of fixed-size elements. This performs no
29 * allocation and can't fail.
30 */
2c5ff4e4 31void lttng_dynamic_array_init(struct lttng_dynamic_array *array,
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32 size_t element_size,
33 lttng_dynamic_array_element_destructor destructor);
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34
35/*
36 * Returns the number of elements in the dynamic array.
37 */
38static inline
39size_t lttng_dynamic_array_get_count(
40 const struct lttng_dynamic_array *array)
41{
42 return array->size;
43}
44
45/*
46 * Returns a pointer to the element. Mutating operations on the array invalidate
47 * the returned pointer.
48 */
49static inline
50void *lttng_dynamic_array_get_element(const struct lttng_dynamic_array *array,
51 size_t element_index)
52{
a0377dfe 53 LTTNG_ASSERT(element_index < array->size);
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54 return array->buffer.data + (element_index * array->element_size);
55}
56
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57/*
58 * Set the array's element count to new_element_count. Any added element will
59 * be zeroed.
60 *
61 * Be careful to expand the array's element count _before_ calling out external
62 * APIs (e.g. read(3)) which may populate the buffer as setting the element
63 * count after will zero-out the result of the operation.
64 *
65 * Shrinking an array does not zero the old content. If the buffer may contain
66 * sensititve information, it must be cleared manually _before_ changing the
67 * size.
68 *
69 * NOTE: It is striclty _invalid_ to access memory after _size_, regardless
70 * of prior calls to set_capacity().
71 */
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72int lttng_dynamic_array_set_count(struct lttng_dynamic_array *array,
73 size_t new_element_count);
74
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75/*
76 * Add an element to the end of a dynamic array. The array's element count is
77 * increased by one and its underlying capacity is adjusted automatically.
78 *
79 * element is a pointer to the element to add (copy) to the array.
80 */
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81int lttng_dynamic_array_add_element(struct lttng_dynamic_array *array,
82 const void *element);
83
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84/*
85 * Remove an element from the dynamic array. The array's element count is
86 * decreased by one and the following elements are shifted to take its place
87 * (when applicable).
88 */
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89int lttng_dynamic_array_remove_element(struct lttng_dynamic_array *array,
90 size_t element_index);
91
2c5ff4e4 92/* Release any memory used by the dynamic array. */
93bed9fe 93void lttng_dynamic_array_reset(struct lttng_dynamic_array *array);
2c5ff4e4 94
74465ffb 95/* Remove all elements from the dynamic array. */
74465ffb 96void lttng_dynamic_array_clear(struct lttng_dynamic_array *array);
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97
98/*
99 * Specialization of lttng_dynamic_array for pointers. This utility
100 * is built under the assumption that pointer sizes are equal
101 * for all data types on supported architectures. Revisit this in the event
102 * of a port to an Harvard architecture.
103 */
104
105/*
106 * Initialize a resizable array of fixed-size elements. This performs no
107 * allocation and can't fail.
108 */
2c5ff4e4 109void lttng_dynamic_pointer_array_init(
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110 struct lttng_dynamic_pointer_array *array,
111 lttng_dynamic_pointer_array_destructor destructor);
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112
113/*
114 * Returns the number of pointers in the dynamic pointer array.
115 */
116static inline
117size_t lttng_dynamic_pointer_array_get_count(
118 const struct lttng_dynamic_pointer_array *array)
119{
120 return lttng_dynamic_array_get_count(&array->array);
121}
122
123/*
14c4262b 124 * Returns the pointer at index `index`.
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125 */
126static inline
127void *lttng_dynamic_pointer_array_get_pointer(
128 const struct lttng_dynamic_pointer_array *array, size_t index)
129{
48a40005 130 void **element = (void **) lttng_dynamic_array_get_element(&array->array, index);
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131
132 return *element;
133}
134
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135/*
136 * Returns the pointer at index `index`, sets the array slot to NULL. Does not
137 * run the destructor.
138 */
139
140static inline
141void *lttng_dynamic_pointer_array_steal_pointer(
142 struct lttng_dynamic_pointer_array *array, size_t index)
143{
48a40005 144 void **p_element = (void **) lttng_dynamic_array_get_element(&array->array, index);
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145 void *element = *p_element;
146
147 *p_element = NULL;
148
149 return element;
150}
151
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152/*
153 * Add a pointer to the end of a dynamic pointer array. The array's element
154 * count is increased by one and its underlying capacity is adjusted
155 * automatically.
156 */
157static inline
158int lttng_dynamic_pointer_array_add_pointer(
159 struct lttng_dynamic_pointer_array *array, void *pointer)
160{
161 return lttng_dynamic_array_add_element(&array->array, &pointer);
162}
163
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164/*
165 * Remove a pointer from a dynamic pointer array. The array's element
166 * count is decreased by one and the following pointers are shifted to
167 * take the place of the removed pointer (if applicable).
168 */
93bed9fe 169int lttng_dynamic_pointer_array_remove_pointer(
0186592a 170 struct lttng_dynamic_pointer_array *array, size_t index);
93bed9fe 171
2c5ff4e4 172/* Release any memory used by the dynamic array. */
2c5ff4e4 173void lttng_dynamic_pointer_array_reset(
93bed9fe 174 struct lttng_dynamic_pointer_array *array);
2c5ff4e4 175
74465ffb 176/* Remove all elements from the dynamic pointer array. */
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177void lttng_dynamic_pointer_array_clear(
178 struct lttng_dynamic_pointer_array *array);
179
2c5ff4e4 180#endif /* LTTNG_DYNAMIC_ARRAY_H */
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