thread.h 10.5 KB
Newer Older
Vicent Marti committed
1
/*
Edward Thomson committed
2
 * Copyright (C) the libgit2 contributors. All rights reserved.
Vicent Marti committed
3 4 5 6
 *
 * This file is part of libgit2, distributed under the GNU GPL v2 with
 * a Linking Exception. For full terms see the included COPYING file.
 */
7 8
#ifndef INCLUDE_thread_h__
#define INCLUDE_thread_h__
9

10 11 12 13 14 15 16 17 18 19 20 21
#if defined(GIT_THREADS)

#if defined(__clang__)

# if (__clang_major__ < 3 || (__clang_major__ == 3 && __clang_minor__ < 1))
#  error Atomic primitives do not exist on this version of clang; configure libgit2 with -DTHREADSAFE=OFF
# else
#  define GIT_BUILTIN_ATOMIC
# endif

#elif defined(__GNUC__)

22 23
# if (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 1))
#  error Atomic primitives do not exist on this version of gcc; configure libgit2 with -DTHREADSAFE=OFF
24
# elif (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 7))
25 26 27 28 29
#  define GIT_BUILTIN_ATOMIC
# else
#  define GIT_BUILTIN_SYNC
# endif

30 31
#endif

32 33
#endif /* GIT_THREADS */

Vicent Marti committed
34 35
/* Common operations even if threading has been disabled */
typedef struct {
36
#if defined(GIT_WIN32)
37 38
	volatile long val;
#else
Vicent Marti committed
39
	volatile int val;
40
#endif
41
} git_atomic32;
Vicent Marti committed
42

43 44
#ifdef GIT_ARCH_64

45 46
typedef struct {
#if defined(GIT_WIN32)
47
	volatile __int64 val;
48
#else
49
	volatile int64_t val;
50 51 52
#endif
} git_atomic64;

53 54
typedef git_atomic64 git_atomic_ssize;

55
#define git_atomic_ssize_set git_atomic64_set
56
#define git_atomic_ssize_add git_atomic64_add
57
#define git_atomic_ssize_get git_atomic64_get
58 59 60

#else

61
typedef git_atomic32 git_atomic_ssize;
62

63 64 65
#define git_atomic_ssize_set git_atomic32_set
#define git_atomic_ssize_add git_atomic32_add
#define git_atomic_ssize_get git_atomic32_get
66 67 68

#endif

Vicent Marti committed
69 70
#ifdef GIT_THREADS

71
#ifdef GIT_WIN32
72
#   include "win32/thread.h"
73
#else
74
#   include "unix/pthread.h"
75
#endif
76

77
GIT_INLINE(void) git_atomic32_set(git_atomic32 *a, int val)
78 79 80
{
#if defined(GIT_WIN32)
	InterlockedExchange(&a->val, (LONG)val);
81 82 83
#elif defined(GIT_BUILTIN_ATOMIC)
	__atomic_store_n(&a->val, val, __ATOMIC_SEQ_CST);
#elif defined(GIT_BUILTIN_SYNC)
84 85 86 87 88 89
	__sync_lock_test_and_set(&a->val, val);
#else
#	error "Unsupported architecture for atomic operations"
#endif
}

90
GIT_INLINE(int) git_atomic32_inc(git_atomic32 *a)
Vicent Marti committed
91
{
92
#if defined(GIT_WIN32)
Vicent Marti committed
93
	return InterlockedIncrement(&a->val);
94 95 96
#elif defined(GIT_BUILTIN_ATOMIC)
	return __atomic_add_fetch(&a->val, 1, __ATOMIC_SEQ_CST);
#elif defined(GIT_BUILTIN_SYNC)
97
	return __sync_add_and_fetch(&a->val, 1);
Vicent Marti committed
98 99 100 101 102
#else
#	error "Unsupported architecture for atomic operations"
#endif
}

103
GIT_INLINE(int) git_atomic32_add(git_atomic32 *a, int32_t addend)
104 105
{
#if defined(GIT_WIN32)
106
	return InterlockedExchangeAdd(&a->val, addend);
107 108 109
#elif defined(GIT_BUILTIN_ATOMIC)
	return __atomic_add_fetch(&a->val, addend, __ATOMIC_SEQ_CST);
#elif defined(GIT_BUILTIN_SYNC)
110 111 112 113 114 115
	return __sync_add_and_fetch(&a->val, addend);
#else
#	error "Unsupported architecture for atomic operations"
#endif
}

116
GIT_INLINE(int) git_atomic32_dec(git_atomic32 *a)
Vicent Marti committed
117
{
118
#if defined(GIT_WIN32)
Vicent Marti committed
119
	return InterlockedDecrement(&a->val);
120 121 122
#elif defined(GIT_BUILTIN_ATOMIC)
	return __atomic_sub_fetch(&a->val, 1, __ATOMIC_SEQ_CST);
#elif defined(GIT_BUILTIN_SYNC)
123
	return __sync_sub_and_fetch(&a->val, 1);
Vicent Marti committed
124 125 126 127 128
#else
#	error "Unsupported architecture for atomic operations"
#endif
}

129
GIT_INLINE(int) git_atomic32_get(git_atomic32 *a)
130 131 132 133 134 135 136 137 138 139 140 141
{
#if defined(GIT_WIN32)
	return (int)InterlockedCompareExchange(&a->val, 0, 0);
#elif defined(GIT_BUILTIN_ATOMIC)
	return __atomic_load_n(&a->val, __ATOMIC_SEQ_CST);
#elif defined(GIT_BUILTIN_SYNC)
	return __sync_val_compare_and_swap(&a->val, 0, 0);
#else
#	error "Unsupported architecture for atomic operations"
#endif
}

142
GIT_INLINE(void *) git_atomic__compare_and_swap(
143
	void * volatile *ptr, void *oldval, void *newval)
144 145
{
#if defined(GIT_WIN32)
146
	volatile void *foundval;
nulltoken committed
147
	foundval = InterlockedCompareExchangePointer((volatile PVOID *)ptr, newval, oldval);
148 149 150 151 152 153
	return (foundval == oldval) ? oldval : newval;
#elif defined(GIT_BUILTIN_ATOMIC)
	bool success = __atomic_compare_exchange(ptr, &oldval, &newval, false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
	return success ? oldval : newval;
#elif defined(GIT_BUILTIN_SYNC)
	volatile void *foundval;
154
	foundval = __sync_val_compare_and_swap(ptr, oldval, newval);
155
	return (foundval == oldval) ? oldval : newval;
156 157 158 159 160
#else
#	error "Unsupported architecture for atomic operations"
#endif
}

161
GIT_INLINE(volatile void *) git_atomic__swap(
162 163 164 165
	void * volatile *ptr, void *newval)
{
#if defined(GIT_WIN32)
	return InterlockedExchangePointer(ptr, newval);
166 167 168 169 170
#elif defined(GIT_BUILTIN_ATOMIC)
	void * volatile foundval;
	__atomic_exchange(ptr, &newval, &foundval, __ATOMIC_SEQ_CST);
	return foundval;
#elif defined(GIT_BUILTIN_SYNC)
171
	return __sync_lock_test_and_set(ptr, newval);
172 173 174 175 176
#else
#	error "Unsupported architecture for atomic operations"
#endif
}

177
GIT_INLINE(volatile void *) git_atomic__load(void * volatile *ptr)
178 179 180 181 182 183 184 185 186 187 188 189
{
#if defined(GIT_WIN32)
	void *newval = NULL, *oldval = NULL;
	volatile void *foundval = NULL;
	foundval = InterlockedCompareExchangePointer((volatile PVOID *)ptr, newval, oldval);
	return foundval;
#elif defined(GIT_BUILTIN_ATOMIC)
	return (volatile void *)__atomic_load_n(ptr, __ATOMIC_SEQ_CST);
#elif defined(GIT_BUILTIN_SYNC)
	return (volatile void *)__sync_val_compare_and_swap(ptr, 0, 0);
#else
#	error "Unsupported architecture for atomic operations"
190 191 192
#endif
}

193 194 195
#ifdef GIT_ARCH_64

GIT_INLINE(int64_t) git_atomic64_add(git_atomic64 *a, int64_t addend)
196 197
{
#if defined(GIT_WIN32)
198
	return InterlockedExchangeAdd64(&a->val, addend);
199 200 201
#elif defined(GIT_BUILTIN_ATOMIC)
	return __atomic_add_fetch(&a->val, addend, __ATOMIC_SEQ_CST);
#elif defined(GIT_BUILTIN_SYNC)
202 203 204 205 206 207
	return __sync_add_and_fetch(&a->val, addend);
#else
#	error "Unsupported architecture for atomic operations"
#endif
}

208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233
GIT_INLINE(void) git_atomic64_set(git_atomic64 *a, int64_t val)
{
#if defined(GIT_WIN32)
	InterlockedExchange64(&a->val, val);
#elif defined(GIT_BUILTIN_ATOMIC)
	__atomic_store_n(&a->val, val, __ATOMIC_SEQ_CST);
#elif defined(GIT_BUILTIN_SYNC)
	__sync_lock_test_and_set(&a->val, val);
#else
#	error "Unsupported architecture for atomic operations"
#endif
}

GIT_INLINE(int64_t) git_atomic64_get(git_atomic64 *a)
{
#if defined(GIT_WIN32)
	return (int64_t)InterlockedCompareExchange64(&a->val, 0, 0);
#elif defined(GIT_BUILTIN_ATOMIC)
	return __atomic_load_n(&a->val, __ATOMIC_SEQ_CST);
#elif defined(GIT_BUILTIN_SYNC)
	return __sync_val_compare_and_swap(&a->val, 0, 0);
#else
#	error "Unsupported architecture for atomic operations"
#endif
}

234 235
#endif

Vicent Marti committed
236 237
#else

238
#define git_threads_global_init git__noop
239

Vicent Marti committed
240
#define git_thread unsigned int
241 242
#define git_thread_create(thread, start_routine, arg) git__noop()
#define git_thread_join(id, status) git__noop()
Vicent Marti committed
243 244 245

/* Pthreads Mutex */
#define git_mutex unsigned int
246 247 248 249 250
#define git_mutex_init(a)	git__noop()
#define git_mutex_init(a)	git__noop()
#define git_mutex_lock(a)	git__noop()
#define git_mutex_unlock(a)	git__noop()
#define git_mutex_free(a)	git__noop()
Vicent Marti committed
251

252
/* Pthreads condition vars */
Vicent Marti committed
253
#define git_cond unsigned int
254 255 256 257 258
#define git_cond_init(c)	git__noop()
#define git_cond_free(c)	git__noop()
#define git_cond_wait(c, l)	git__noop()
#define git_cond_signal(c)	git__noop()
#define git_cond_broadcast(c)	git__noop()
Vicent Marti committed
259

260 261
/* Pthreads rwlock */
#define git_rwlock unsigned int
262 263 264 265 266 267
#define git_rwlock_init(a)	git__noop()
#define git_rwlock_rdlock(a)	git__noop()
#define git_rwlock_rdunlock(a)	git__noop()
#define git_rwlock_wrlock(a)	git__noop()
#define git_rwlock_wrunlock(a)	git__noop()
#define git_rwlock_free(a)	git__noop()
268 269 270
#define GIT_RWLOCK_STATIC_INIT	0


271
GIT_INLINE(void) git_atomic32_set(git_atomic32 *a, int val)
272 273 274 275
{
	a->val = val;
}

276
GIT_INLINE(int) git_atomic32_inc(git_atomic32 *a)
Vicent Marti committed
277 278 279 280
{
	return ++a->val;
}

281
GIT_INLINE(int) git_atomic32_add(git_atomic32 *a, int32_t addend)
282 283 284 285 286
{
	a->val += addend;
	return a->val;
}

287
GIT_INLINE(int) git_atomic32_dec(git_atomic32 *a)
Vicent Marti committed
288 289 290 291
{
	return --a->val;
}

292
GIT_INLINE(int) git_atomic32_get(git_atomic32 *a)
293 294 295 296
{
	return (int)a->val;
}

297
GIT_INLINE(void *) git_atomic__compare_and_swap(
298
	void * volatile *ptr, void *oldval, void *newval)
299 300 301 302 303 304 305 306
{
	if (*ptr == oldval)
		*ptr = newval;
	else
		oldval = newval;
	return oldval;
}

307
GIT_INLINE(volatile void *) git_atomic__swap(
308 309 310 311 312 313 314
	void * volatile *ptr, void *newval)
{
	volatile void *old = *ptr;
	*ptr = newval;
	return old;
}

315
GIT_INLINE(volatile void *) git_atomic__load(void * volatile *ptr)
316 317 318 319
{
	return *ptr;
}

320 321 322
#ifdef GIT_ARCH_64

GIT_INLINE(int64_t) git_atomic64_add(git_atomic64 *a, int64_t addend)
323 324 325 326 327
{
	a->val += addend;
	return a->val;
}

328 329 330 331
GIT_INLINE(void) git_atomic64_set(git_atomic64 *a, int64_t val)
{
	a->val = val;
}
332

333
GIT_INLINE(int64_t) git_atomic64_get(git_atomic64 *a)
334
{
335
	return (int64_t)a->val;
336 337
}

338 339 340 341
#endif

#endif

342 343 344
/* Atomically replace oldval with newval
 * @return oldval if it was replaced or newval if it was not
 */
345 346
#define git_atomic_compare_and_swap(P,O,N) \
	git_atomic__compare_and_swap((void * volatile *)P, O, N)
347

348 349
#define git_atomic_swap(ptr, val) \
	(void *)git_atomic__swap((void * volatile *)&ptr, val)
350

351 352
#define git_atomic_load(ptr) \
	(void *)git_atomic__load((void * volatile *)&ptr)
353 354 355 356 357 358 359 360 361 362 363

#if defined(GIT_THREADS)

# if defined(GIT_WIN32)
#  define GIT_MEMORY_BARRIER MemoryBarrier()
# elif defined(GIT_BUILTIN_ATOMIC)
#  define GIT_MEMORY_BARRIER __atomic_thread_fence(__ATOMIC_SEQ_CST)
# elif defined(GIT_BUILTIN_SYNC)
#  define GIT_MEMORY_BARRIER __sync_synchronize()
# endif

364
#else
365

366
# define GIT_MEMORY_BARRIER /* noop */
367

368 369
#endif

370 371 372 373 374 375 376 377 378 379 380
/* Thread-local data */

#if !defined(GIT_THREADS)
# define git_tlsdata_key int
#elif defined(GIT_WIN32)
# define git_tlsdata_key DWORD
#elif defined(_POSIX_THREADS)
# define git_tlsdata_key pthread_key_t
#else
# error unknown threading model
#endif
381 382

/**
383 384 385
 * Create a thread-local data key.  The destroy function will be
 * called upon thread exit.  On some platforms, it may be called
 * when all threads have deleted their keys.
386
 *
387 388 389
 * Note that the tlsdata functions do not set an error message on
 * failure; this is because the error handling in libgit2 is itself
 * handled by thread-local data storage.
390
 *
391 392
 * @param key the tlsdata key
 * @param destroy_fn function pointer called upon thread exit
393 394
 * @return 0 on success, non-zero on failure
 */
395
int git_tlsdata_init(git_tlsdata_key *key, void (GIT_SYSTEM_CALL *destroy_fn)(void *));
396 397

/**
398
 * Set a the thread-local value for the given key.
399
 *
400 401
 * @param key the tlsdata key to store data on
 * @param value the pointer to store
402 403
 * @return 0 on success, non-zero on failure
 */
404
int git_tlsdata_set(git_tlsdata_key key, void *value);
405 406

/**
407
 * Get the thread-local value for the given key.
408
 *
409 410
 * @param key the tlsdata key to retrieve the value of
 * @return the pointer stored with git_tlsdata_set
411
 */
412
void *git_tlsdata_get(git_tlsdata_key key);
413 414

/**
415
 * Delete the given thread-local key.
416
 *
417 418
 * @param key the tlsdata key to dispose
 * @return 0 on success, non-zero on failure
419
 */
420
int git_tlsdata_dispose(git_tlsdata_key key);
421

422
#endif