/src/aom/aom_ports/aom_once.h
Line | Count | Source |
1 | | /* |
2 | | * Copyright (c) 2016, Alliance for Open Media. All rights reserved. |
3 | | * |
4 | | * This source code is subject to the terms of the BSD 2 Clause License and |
5 | | * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License |
6 | | * was not distributed with this source code in the LICENSE file, you can |
7 | | * obtain it at www.aomedia.org/license/software. If the Alliance for Open |
8 | | * Media Patent License 1.0 was not distributed with this source code in the |
9 | | * PATENTS file, you can obtain it at www.aomedia.org/license/patent. |
10 | | */ |
11 | | |
12 | | #ifndef AOM_AOM_PORTS_AOM_ONCE_H_ |
13 | | #define AOM_AOM_PORTS_AOM_ONCE_H_ |
14 | | |
15 | | #include "config/aom_config.h" |
16 | | |
17 | | /* Implement a function wrapper to guarantee initialization |
18 | | * thread-safety for library singletons. |
19 | | * |
20 | | * NOTE: This function uses static locks, and can only be |
21 | | * used with one common argument per compilation unit. So |
22 | | * |
23 | | * file1.c: |
24 | | * aom_once(foo); |
25 | | * ... |
26 | | * aom_once(foo); |
27 | | * |
28 | | * file2.c: |
29 | | * aom_once(bar); |
30 | | * |
31 | | * will ensure foo() and bar() are each called only once, but in |
32 | | * |
33 | | * file1.c: |
34 | | * aom_once(foo); |
35 | | * aom_once(bar): |
36 | | * |
37 | | * bar() will never be called because the lock is used up |
38 | | * by the call to foo(). |
39 | | */ |
40 | | |
41 | | #if CONFIG_MULTITHREAD && defined(_WIN32) |
42 | | #undef WIN32_LEAN_AND_MEAN |
43 | | #define WIN32_LEAN_AND_MEAN |
44 | | #include <windows.h> |
45 | | /* Declare a per-compilation-unit state variable to track the progress |
46 | | * of calling func() only once. This must be at global scope because |
47 | | * local initializers are not thread-safe in MSVC prior to Visual |
48 | | * Studio 2015. |
49 | | */ |
50 | | static INIT_ONCE aom_init_once = INIT_ONCE_STATIC_INIT; |
51 | | |
52 | | static void aom_once(void (*func)(void)) { |
53 | | BOOL pending; |
54 | | InitOnceBeginInitialize(&aom_init_once, 0, &pending, NULL); |
55 | | if (!pending) { |
56 | | // Initialization has already completed. |
57 | | return; |
58 | | } |
59 | | func(); |
60 | | InitOnceComplete(&aom_init_once, 0, NULL); |
61 | | } |
62 | | |
63 | | #elif CONFIG_MULTITHREAD && HAVE_PTHREAD_H |
64 | | #include <pthread.h> |
65 | 80.5k | static void aom_once(void (*func)(void)) { |
66 | 80.5k | static pthread_once_t lock = PTHREAD_ONCE_INIT; |
67 | 80.5k | pthread_once(&lock, func); |
68 | 80.5k | } Line | Count | Source | 65 | 16.1k | static void aom_once(void (*func)(void)) { | 66 | 16.1k | static pthread_once_t lock = PTHREAD_ONCE_INIT; | 67 | 16.1k | pthread_once(&lock, func); | 68 | 16.1k | } |
aom_scale_rtcd.c:aom_once Line | Count | Source | 65 | 16.1k | static void aom_once(void (*func)(void)) { | 66 | 16.1k | static pthread_once_t lock = PTHREAD_ONCE_INIT; | 67 | 16.1k | pthread_once(&lock, func); | 68 | 16.1k | } |
Line | Count | Source | 65 | 16.1k | static void aom_once(void (*func)(void)) { | 66 | 16.1k | static pthread_once_t lock = PTHREAD_ONCE_INIT; | 67 | 16.1k | pthread_once(&lock, func); | 68 | 16.1k | } |
Line | Count | Source | 65 | 16.1k | static void aom_once(void (*func)(void)) { | 66 | 16.1k | static pthread_once_t lock = PTHREAD_ONCE_INIT; | 67 | 16.1k | pthread_once(&lock, func); | 68 | 16.1k | } |
Line | Count | Source | 65 | 16.1k | static void aom_once(void (*func)(void)) { | 66 | 16.1k | static pthread_once_t lock = PTHREAD_ONCE_INIT; | 67 | 16.1k | pthread_once(&lock, func); | 68 | 16.1k | } |
|
69 | | |
70 | | #else |
71 | | /* Default version that performs no synchronization. */ |
72 | | |
73 | | static void aom_once(void (*func)(void)) { |
74 | | static volatile int done; |
75 | | |
76 | | if (!done) { |
77 | | func(); |
78 | | done = 1; |
79 | | } |
80 | | } |
81 | | #endif |
82 | | |
83 | | #endif // AOM_AOM_PORTS_AOM_ONCE_H_ |