Fix: src.ctf.fs: initialize the other_entry variable
[babeltrace.git] / src / lib / object-pool.h
CommitLineData
312c056a
PP
1#ifndef BABELTRACE_OBJECT_POOL_INTERNAL_H
2#define BABELTRACE_OBJECT_POOL_INTERNAL_H
3
4/*
312c056a
PP
5 * Copyright (c) 2018 Philippe Proulx <pproulx@efficios.com>
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/*
27 * This is a generic object pool to avoid memory allocation/deallocation
28 * for objects of which the lifespan is typically short, but which are
29 * created a lot.
30 *
31 * The object pool, thanks to two user functions, knows how to allocate
32 * a brand new object in memory when the pool is empty and how to
33 * destroy an object when we destroy the pool.
34 *
35 * The object pool's user is responsible for:
36 *
37 * * Setting whatever references the object needs to keep and reset some
38 * properties _after_ calling bt_object_pool_create_object(). This is
39 * typically done in the bt_*_create() function which calls
40 * bt_object_pool_create_object() (which could call the user-provided
41 * allocation function if the pool is empty) and then sets the
42 * appropriate properties on the possibly recycled object.
43 *
44 * * Releasing whatever references the object keeps _before_ calling
45 * bt_object_pool_recycle_object(). This is typically done in a custom
46 * bt_*_recycle() function which does the necessary before calling
47 * bt_object_pool_recycle_object() with an object ready to be reused
48 * at any time.
49 */
50
51#include <glib.h>
578e048b 52#include "lib/object.h"
312c056a 53
130f527c
PP
54/* Protection: this file uses BT_LIB_LOG*() macros directly */
55#ifndef BT_LIB_LOG_SUPPORTED
56# error Please include "lib/logging.h" before including this file.
57#endif
58
312c056a 59typedef void *(*bt_object_pool_new_object_func)(void *data);
9c7f2f85 60typedef void (*bt_object_pool_destroy_object_func)(void *obj, void *data);
312c056a
PP
61
62struct bt_object_pool {
63 /*
64 * Container of recycled objects, owned by this. The array's size
65 * is the pool's capacity.
66 */
67 GPtrArray *objects;
68
69 /*
70 * Pool's size, that is, number of elements in the array above,
71 * starting at index 0, which exist as recycled objects.
72 */
73 size_t size;
74
75 /* User functions */
76 struct {
77 /* Allocate a new object in memory */
78 bt_object_pool_new_object_func new_object;
79
80 /* Free direct and indirect memory occupied by object */
81 bt_object_pool_destroy_object_func destroy_object;
82 } funcs;
83
84 /* User data passed to user functions */
85 void *data;
86};
87
88/*
89 * Initializes an object pool which is already allocated.
90 */
13f9fa40 91BT_HIDDEN
312c056a
PP
92int bt_object_pool_initialize(struct bt_object_pool *pool,
93 bt_object_pool_new_object_func new_object_func,
94 bt_object_pool_destroy_object_func destroy_object_func,
95 void *data);
96
97/*
98 * Finalizes an object pool without deallocating it.
99 */
13f9fa40 100BT_HIDDEN
312c056a
PP
101void bt_object_pool_finalize(struct bt_object_pool *pool);
102
103/*
104 * Creates an object from an object pool. If the pool is empty, this
105 * function calls the "new" user function to allocate a new object
106 * before returning it. Otherwise this function returns a recycled
107 * object, removing it from the pool.
108 *
109 * The returned object is owned by the caller.
110 */
111static inline
112void *bt_object_pool_create_object(struct bt_object_pool *pool)
113{
114 struct bt_object *obj;
115
98b15851 116 BT_ASSERT_DBG(pool);
ef267d12 117 BT_LOGT("Creating object from pool: pool-addr=%p, pool-size=%zu, pool-cap=%u",
312c056a 118 pool, pool->size, pool->objects->len);
312c056a
PP
119
120 if (pool->size > 0) {
121 /* Pick one from the pool */
122 pool->size--;
123 obj = pool->objects->pdata[pool->size];
124 pool->objects->pdata[pool->size] = NULL;
312c056a
PP
125 goto end;
126 }
127
128 /* Pool is empty: create a brand new object */
3f7d4d90 129 BT_LOGD("Pool is empty: allocating new object: pool-addr=%p",
312c056a 130 pool);
312c056a
PP
131 obj = pool->funcs.new_object(pool->data);
132
133end:
ef267d12 134 BT_LOGT("Created one object from pool: pool-addr=%p, obj-addr=%p",
312c056a 135 pool, obj);
312c056a
PP
136 return obj;
137}
138
139/*
140 * Recycles an object, that is, puts it back into the pool.
141 *
142 * The pool becomes the sole owner of the object to recycle.
143 */
144static inline
145void bt_object_pool_recycle_object(struct bt_object_pool *pool, void *obj)
146{
cdc4693d
PP
147 struct bt_object *bt_obj = obj;
148
98b15851
PP
149 BT_ASSERT_DBG(pool);
150 BT_ASSERT_DBG(obj);
ef267d12 151 BT_LOGT("Recycling object: pool-addr=%p, pool-size=%zu, pool-cap=%u, obj-addr=%p",
312c056a 152 pool, pool->size, pool->objects->len, obj);
312c056a
PP
153
154 if (pool->size == pool->objects->len) {
155 /* Backing array is full: make place for recycled object */
3f7d4d90 156 BT_LOGD("Object pool is full: increasing object pool capacity: "
312c056a
PP
157 "pool-addr=%p, old-pool-cap=%u, new-pool-cap=%u",
158 pool, pool->objects->len, pool->objects->len + 1);
312c056a
PP
159 g_ptr_array_set_size(pool->objects, pool->size + 1);
160 }
161
cdc4693d 162 /* Reset reference count to 1 since it could be 0 now */
3fea54f6 163 bt_obj->ref_count = 1;
cdc4693d
PP
164
165 /* Back to the pool */
312c056a
PP
166 pool->objects->pdata[pool->size] = obj;
167 pool->size++;
ef267d12 168 BT_LOGT("Recycled object: pool-addr=%p, pool-size=%zu, pool-cap=%u, obj-addr=%p",
312c056a 169 pool, pool->size, pool->objects->len, obj);
312c056a
PP
170}
171
172#endif /* BABELTRACE_OBJECT_POOL_INTERNAL_H */
This page took 0.07704 seconds and 4 git commands to generate.