Posix synchronized init, prototype win32 version
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diff --git a/src/global.c b/src/global.c
index 4f024f1..fe3a3c8 100644
--- a/src/global.c
+++ b/src/global.c
@@ -18,6 +18,7 @@ git_mutex git__mwindow_mutex;
git_global_shutdown_fn git__shutdown_callbacks[MAX_SHUTDOWN_CB];
git_atomic git__n_shutdown_callbacks;
+git_atomic git__n_inits;
void git__on_shutdown(git_global_shutdown_fn callback)
{
@@ -73,47 +74,99 @@ static void git__shutdown(void)
#if defined(GIT_THREADS) && defined(GIT_WIN32)
static DWORD _tls_index;
-static int _tls_init = 0;
+static HANDLE _init_mutex = NULL;
+static HANDLE _initialized_event = NULL;
-int git_threads_init(void)
+static int synchronized_init_and_claim_mutex(volatile HANDLE *m)
+{
+ if (*m == NULL) {
+ HANDLE nm = CreateMutex(NULL, FALSE, NULL);
+ if (InterlockedCompareExchangePointer(m, nm, NULL) != NULL) {
+ CloseHandle(nm);
+ }
+ }
+ return WaitForSingleObject(*m, INFINITE) == WAIT_FAILED;
+}
+
+static int synchronized_threads_init()
{
int error;
- if (_tls_init)
- return 0;
+ if (synchronized_init_and_claim_mutex(&_init_mutex) != WAIT_OBJECT_0) {
+ giterr_set(GITERR_OS, "git_threads_init: WaitForSingleObject failed");
+ return -1;
+ }
+
+ if (!_initialized_event) {
+ _initialized_event = CreateEvent(NULL, TRUE, FALSE, NULL);
+ }
_tls_index = TlsAlloc();
if (git_mutex_init(&git__mwindow_mutex))
return -1;
/* Initialize any other subsystems that have global state */
- if ((error = git_hash_global_init()) >= 0 &&
- (error = git_futils_dirs_global_init()) >= 0)
- _tls_init = 1;
-
- GIT_MEMORY_BARRIER;
+ if ((error = git_hash_global_init()) >= 0)
+ error = git_futils_dirs_global_init();
win32_pthread_initialize();
+ SetEvent(_initialized_event);
+ ReleaseMutex(_init_mutex);
+ return error;
+}
+
+int git_threads_init(void)
+{
+ int error = -1,
+ n_inits = git_atomic_inc(&git__n_inits);
+
+ if (n_inits == 1)
+ error = synchronized_threads_init();
+ else {
+ while (!_initialized_event); /* SPIN */
+ error = (WaitForSingleObject(_initialized_event, INFINITE) == WAIT_OBJECT_0) ? 0 : -1;
+ }
+ GIT_MEMORY_BARRIER;
return error;
}
-void git_threads_shutdown(void)
+static void synchronized_threads_shutdown()
{
+ if (WaitForSingleObject(_init_mutex, INFINITE) != WAIT_OBJECT_0) {
+ giterr_set(GITERR_OS, "git_threads_shutdown: WaitForSingleObject failed");
+ return;
+ }
+
+ if (git__n_inits.val != 0) {
+ /* Someone else initialized while we were waiting */
+ ReleaseMutex(_init_mutex);
+ return;
+ }
+ ResetEvent(_initialized_event);
+
/* Shut down any subsystems that have global state */
git__shutdown();
-
TlsFree(_tls_index);
- _tls_init = 0;
-
git_mutex_free(&git__mwindow_mutex);
+
+ ReleaseMutex(_init_mutex);
+}
+
+void git_threads_shutdown(void)
+{
+ int n_inits = git_atomic_dec(&git__n_inits);
+
+ if (n_inits == 0)
+ synchronized_threads_shutdown();
+ GIT_MEMORY_BARRIER;
}
git_global_st *git__global_state(void)
{
void *ptr;
- assert(_tls_init);
+ assert(git__n_inits.val);
if ((ptr = TlsGetValue(_tls_index)) != NULL)
return ptr;
@@ -130,55 +183,57 @@ git_global_st *git__global_state(void)
#elif defined(GIT_THREADS) && defined(_POSIX_THREADS)
static pthread_key_t _tls_key;
-static int _tls_init = 0;
+static pthread_once_t _once_init = PTHREAD_ONCE_INIT;
+int init_error = 0;
static void cb__free_status(void *st)
{
git__free(st);
}
-int git_threads_init(void)
+static void init_once(void)
{
- int error = 0;
-
- if (_tls_init)
- return 0;
-
- if (git_mutex_init(&git__mwindow_mutex))
- return -1;
+ if ((init_error = git_mutex_init(&git__mwindow_mutex)) != 0)
+ return;
pthread_key_create(&_tls_key, &cb__free_status);
/* Initialize any other subsystems that have global state */
- if ((error = git_hash_global_init()) >= 0 &&
- (error = git_futils_dirs_global_init()) >= 0)
- _tls_init = 1;
+ if ((init_error = git_hash_global_init()) >= 0)
+ init_error = git_futils_dirs_global_init();
GIT_MEMORY_BARRIER;
+}
- return error;
+int git_threads_init(void)
+{
+ pthread_once(&_once_init, init_once);
+ git_atomic_inc(&git__n_inits);
+ return init_error;
}
void git_threads_shutdown(void)
{
+ pthread_once_t new_once = PTHREAD_ONCE_INIT;
+
+ if (git_atomic_dec(&git__n_inits) > 0) return;
+
/* Shut down any subsystems that have global state */
git__shutdown();
- if (_tls_init) {
- void *ptr = pthread_getspecific(_tls_key);
- pthread_setspecific(_tls_key, NULL);
- git__free(ptr);
- }
+ void *ptr = pthread_getspecific(_tls_key);
+ pthread_setspecific(_tls_key, NULL);
+ git__free(ptr);
pthread_key_delete(_tls_key);
- _tls_init = 0;
git_mutex_free(&git__mwindow_mutex);
+ _once_init = new_once;
}
git_global_st *git__global_state(void)
{
void *ptr;
- assert(_tls_init);
+ assert(git__n_inits.val);
if ((ptr = pthread_getspecific(_tls_key)) != NULL)
return ptr;