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
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
|
/*
Simple DirectMedia Layer
Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/
#include "SDL_internal.h"
/**
* Implementation based on Slim Reader/Writer (SRW) Locks for Win 7 and newer.
*/
// This header makes sure SRWLOCK is actually declared, even on ancient WinSDKs.
#include "SDL_sysmutex_c.h"
typedef VOID(WINAPI *pfnInitializeSRWLock)(PSRWLOCK);
typedef VOID(WINAPI *pfnReleaseSRWLockShared)(PSRWLOCK);
typedef VOID(WINAPI *pfnAcquireSRWLockShared)(PSRWLOCK);
typedef BOOLEAN(WINAPI *pfnTryAcquireSRWLockShared)(PSRWLOCK);
typedef VOID(WINAPI *pfnReleaseSRWLockExclusive)(PSRWLOCK);
typedef VOID(WINAPI *pfnAcquireSRWLockExclusive)(PSRWLOCK);
typedef BOOLEAN(WINAPI *pfnTryAcquireSRWLockExclusive)(PSRWLOCK);
static pfnInitializeSRWLock pInitializeSRWLock = NULL;
static pfnReleaseSRWLockShared pReleaseSRWLockShared = NULL;
static pfnAcquireSRWLockShared pAcquireSRWLockShared = NULL;
static pfnTryAcquireSRWLockShared pTryAcquireSRWLockShared = NULL;
static pfnReleaseSRWLockExclusive pReleaseSRWLockExclusive = NULL;
static pfnAcquireSRWLockExclusive pAcquireSRWLockExclusive = NULL;
static pfnTryAcquireSRWLockExclusive pTryAcquireSRWLockExclusive = NULL;
typedef SDL_RWLock *(*pfnSDL_CreateRWLock)(void);
typedef void (*pfnSDL_DestroyRWLock)(SDL_RWLock *);
typedef void (*pfnSDL_LockRWLockForReading)(SDL_RWLock *);
typedef void (*pfnSDL_LockRWLockForWriting)(SDL_RWLock *);
typedef bool (*pfnSDL_TryLockRWLockForReading)(SDL_RWLock *);
typedef bool (*pfnSDL_TryLockRWLockForWriting)(SDL_RWLock *);
typedef void (*pfnSDL_UnlockRWLock)(SDL_RWLock *);
typedef struct SDL_rwlock_impl_t
{
pfnSDL_CreateRWLock Create;
pfnSDL_DestroyRWLock Destroy;
pfnSDL_LockRWLockForReading LockForReading;
pfnSDL_LockRWLockForWriting LockForWriting;
pfnSDL_TryLockRWLockForReading TryLockForReading;
pfnSDL_TryLockRWLockForWriting TryLockForWriting;
pfnSDL_UnlockRWLock Unlock;
} SDL_rwlock_impl_t;
// Implementation will be chosen at runtime based on available Kernel features
static SDL_rwlock_impl_t SDL_rwlock_impl_active = { 0 };
// rwlock implementation using Win7+ slim read/write locks (SRWLOCK)
typedef struct SDL_rwlock_srw
{
SRWLOCK srw;
SDL_ThreadID write_owner;
} SDL_rwlock_srw;
static SDL_RWLock *SDL_CreateRWLock_srw(void)
{
SDL_rwlock_srw *rwlock = (SDL_rwlock_srw *)SDL_calloc(1, sizeof(*rwlock));
if (rwlock) {
pInitializeSRWLock(&rwlock->srw);
}
return (SDL_RWLock *)rwlock;
}
static void SDL_DestroyRWLock_srw(SDL_RWLock *_rwlock)
{
SDL_rwlock_srw *rwlock = (SDL_rwlock_srw *) _rwlock;
// There are no kernel allocated resources
SDL_free(rwlock);
}
static void SDL_LockRWLockForReading_srw(SDL_RWLock *_rwlock) SDL_NO_THREAD_SAFETY_ANALYSIS // clang doesn't know about NULL mutexes
{
SDL_rwlock_srw *rwlock = (SDL_rwlock_srw *) _rwlock;
pAcquireSRWLockShared(&rwlock->srw);
}
static void SDL_LockRWLockForWriting_srw(SDL_RWLock *_rwlock) SDL_NO_THREAD_SAFETY_ANALYSIS // clang doesn't know about NULL mutexes
{
SDL_rwlock_srw *rwlock = (SDL_rwlock_srw *) _rwlock;
pAcquireSRWLockExclusive(&rwlock->srw);
rwlock->write_owner = SDL_GetCurrentThreadID();
}
static bool SDL_TryLockRWLockForReading_srw(SDL_RWLock *_rwlock)
{
SDL_rwlock_srw *rwlock = (SDL_rwlock_srw *) _rwlock;
return pTryAcquireSRWLockShared(&rwlock->srw);
}
static bool SDL_TryLockRWLockForWriting_srw(SDL_RWLock *_rwlock)
{
SDL_rwlock_srw *rwlock = (SDL_rwlock_srw *) _rwlock;
if (pTryAcquireSRWLockExclusive(&rwlock->srw)) {
rwlock->write_owner = SDL_GetCurrentThreadID();
return true;
} else {
return false;
}
}
static void SDL_UnlockRWLock_srw(SDL_RWLock *_rwlock) SDL_NO_THREAD_SAFETY_ANALYSIS // clang doesn't know about NULL mutexes
{
SDL_rwlock_srw *rwlock = (SDL_rwlock_srw *) _rwlock;
if (rwlock->write_owner == SDL_GetCurrentThreadID()) {
rwlock->write_owner = 0;
pReleaseSRWLockExclusive(&rwlock->srw);
} else {
pReleaseSRWLockShared(&rwlock->srw);
}
}
static const SDL_rwlock_impl_t SDL_rwlock_impl_srw = {
&SDL_CreateRWLock_srw,
&SDL_DestroyRWLock_srw,
&SDL_LockRWLockForReading_srw,
&SDL_LockRWLockForWriting_srw,
&SDL_TryLockRWLockForReading_srw,
&SDL_TryLockRWLockForWriting_srw,
&SDL_UnlockRWLock_srw
};
#include "../generic/SDL_sysrwlock_c.h"
// Generic rwlock implementation using SDL_Mutex, SDL_Condition, and SDL_AtomicInt
static const SDL_rwlock_impl_t SDL_rwlock_impl_generic = {
&SDL_CreateRWLock_generic,
&SDL_DestroyRWLock_generic,
&SDL_LockRWLockForReading_generic,
&SDL_LockRWLockForWriting_generic,
&SDL_TryLockRWLockForReading_generic,
&SDL_TryLockRWLockForWriting_generic,
&SDL_UnlockRWLock_generic
};
SDL_RWLock *SDL_CreateRWLock(void)
{
if (!SDL_rwlock_impl_active.Create) {
// Default to generic implementation, works with all mutex implementations
const SDL_rwlock_impl_t *impl = &SDL_rwlock_impl_generic;
{
HMODULE kernel32 = GetModuleHandle(TEXT("kernel32.dll"));
if (kernel32) {
bool okay = true;
#define LOOKUP_SRW_SYM(sym) if (okay) { if ((p##sym = (pfn##sym)GetProcAddress(kernel32, #sym)) == NULL) { okay = false; } }
LOOKUP_SRW_SYM(InitializeSRWLock);
LOOKUP_SRW_SYM(ReleaseSRWLockShared);
LOOKUP_SRW_SYM(AcquireSRWLockShared);
LOOKUP_SRW_SYM(TryAcquireSRWLockShared);
LOOKUP_SRW_SYM(ReleaseSRWLockExclusive);
LOOKUP_SRW_SYM(AcquireSRWLockExclusive);
LOOKUP_SRW_SYM(TryAcquireSRWLockExclusive);
#undef LOOKUP_SRW_SYM
if (okay) {
impl = &SDL_rwlock_impl_srw; // Use the Windows provided API instead of generic fallback
}
}
}
SDL_copyp(&SDL_rwlock_impl_active, impl);
}
return SDL_rwlock_impl_active.Create();
}
void SDL_DestroyRWLock(SDL_RWLock *rwlock)
{
if (rwlock) {
SDL_rwlock_impl_active.Destroy(rwlock);
}
}
void SDL_LockRWLockForReading(SDL_RWLock *rwlock) SDL_NO_THREAD_SAFETY_ANALYSIS // clang doesn't know about NULL mutexes
{
if (rwlock) {
SDL_rwlock_impl_active.LockForReading(rwlock);
}
}
void SDL_LockRWLockForWriting(SDL_RWLock *rwlock) SDL_NO_THREAD_SAFETY_ANALYSIS // clang doesn't know about NULL mutexes
{
if (rwlock) {
SDL_rwlock_impl_active.LockForWriting(rwlock);
}
}
bool SDL_TryLockRWLockForReading(SDL_RWLock *rwlock)
{
bool result = true;
if (rwlock) {
result = SDL_rwlock_impl_active.TryLockForReading(rwlock);
}
return result;
}
bool SDL_TryLockRWLockForWriting(SDL_RWLock *rwlock)
{
bool result = true;
if (rwlock) {
result = SDL_rwlock_impl_active.TryLockForWriting(rwlock);
}
return result;
}
void SDL_UnlockRWLock(SDL_RWLock *rwlock) SDL_NO_THREAD_SAFETY_ANALYSIS // clang doesn't know about NULL mutexes
{
if (rwlock) {
SDL_rwlock_impl_active.Unlock(rwlock);
}
}
|
