1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
|
/*
* This file is part of mpv.
*
* mpv is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* mpv is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with mpv; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "config.h"
#include <stddef.h>
#include <stdbool.h>
#include <assert.h>
#include "talloc.h"
#include "mpvcore/mp_common.h"
#include "video/mp_image.h"
#include "mp_image_pool.h"
#if HAVE_PTHREADS
#include <pthread.h>
static pthread_mutex_t pool_mutex = PTHREAD_MUTEX_INITIALIZER;
#define pool_lock() pthread_mutex_lock(&pool_mutex)
#define pool_unlock() pthread_mutex_unlock(&pool_mutex)
#else
#define pool_lock() 0
#define pool_unlock() 0
#endif
// Thread-safety: the pool itself is not thread-safe, but pool-allocated images
// can be referenced and unreferenced from other threads. (As long as compiled
// with pthreads, and the image destructors are thread-safe.)
struct mp_image_pool {
int max_count;
struct mp_image **images;
int num_images;
};
// Used to gracefully handle the case when the pool is freed while image
// references allocated from the image pool are still held by someone.
struct image_flags {
// If both of these are false, the image must be freed.
bool referenced; // outside mp_image reference exists
bool pool_alive; // the mp_image_pool references this
};
static void image_pool_destructor(void *ptr)
{
struct mp_image_pool *pool = ptr;
mp_image_pool_clear(pool);
}
struct mp_image_pool *mp_image_pool_new(int max_count)
{
struct mp_image_pool *pool = talloc_ptrtype(NULL, pool);
talloc_set_destructor(pool, image_pool_destructor);
*pool = (struct mp_image_pool) {
.max_count = max_count,
};
return pool;
}
void mp_image_pool_clear(struct mp_image_pool *pool)
{
for (int n = 0; n < pool->num_images; n++) {
struct mp_image *img = pool->images[n];
struct image_flags *it = img->priv;
bool referenced;
pool_lock();
assert(it->pool_alive);
it->pool_alive = false;
referenced = it->referenced;
pool_unlock();
if (!referenced)
talloc_free(img);
}
pool->num_images = 0;
}
// This is the only function that is allowed to run in a different thread.
// (Consider passing an image to another thread, which frees it.)
static void unref_image(void *ptr)
{
struct mp_image *img = ptr;
struct image_flags *it = img->priv;
bool alive;
pool_lock();
assert(it->referenced);
it->referenced = false;
alive = it->pool_alive;
pool_unlock();
if (!alive)
talloc_free(img);
}
// Return a new image of given format/size. The only difference to
// mp_image_alloc() is that there is a transparent mechanism to recycle image
// data allocations through this pool.
// The image can be free'd with talloc_free().
struct mp_image *mp_image_pool_get(struct mp_image_pool *pool, unsigned int fmt,
int w, int h)
{
struct mp_image *new = NULL;
pool_lock();
for (int n = 0; n < pool->num_images; n++) {
struct mp_image *img = pool->images[n];
struct image_flags *it = img->priv;
assert(it->pool_alive);
if (!it->referenced) {
if (img->imgfmt == fmt && img->w == w && img->h == h) {
new = img;
break;
}
}
}
pool_unlock();
if (!new) {
if (pool->num_images >= pool->max_count)
mp_image_pool_clear(pool);
new = mp_image_alloc(fmt, w, h);
struct image_flags *it = talloc_ptrtype(new, it);
*it = (struct image_flags) { .pool_alive = true };
new->priv = it;
MP_TARRAY_APPEND(pool, pool->images, pool->num_images, new);
}
struct image_flags *it = new->priv;
assert(!it->referenced && it->pool_alive);
it->referenced = true;
return mp_image_new_custom_ref(new, new, unref_image);
}
// Like mp_image_new_copy(), but allocate the image out of the pool.
struct mp_image *mp_image_pool_new_copy(struct mp_image_pool *pool,
struct mp_image *img)
{
struct mp_image *new = mp_image_pool_get(pool, img->imgfmt, img->w, img->h);
mp_image_copy(new, img);
mp_image_copy_attributes(new, img);
return new;
}
// Like mp_image_make_writeable(), but if a copy has to be made, allocate it
// out of the pool.
void mp_image_pool_make_writeable(struct mp_image_pool *pool,
struct mp_image *img)
{
if (mp_image_is_writeable(img))
return;
mp_image_steal_data(img, mp_image_pool_new_copy(pool, img));
assert(mp_image_is_writeable(img));
}
|
