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win32: Add 'shared' support to SRWLock emulation

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This commit is contained in:
Ryan Lortie 2011-09-20 10:06:57 -04:00
parent 9f42e3be1b
commit 2539bd007d
1 changed files with 108 additions and 0 deletions
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108
glib/gthread-win32.c
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@ -106,6 +106,9 @@ typedef struct
void (__stdcall * AcquireSRWLockExclusive) (gpointer lock);
BOOLEAN (__stdcall * TryAcquireSRWLockExclusive) (gpointer lock);
void (__stdcall * ReleaseSRWLockExclusive) (gpointer lock);
void (__stdcall * AcquireSRWLockShared) (gpointer lock);
BOOLEAN (__stdcall * TryAcquireSRWLockShared) (gpointer lock);
void (__stdcall * ReleaseSRWLockShared) (gpointer lock);
void (__stdcall * InitializeConditionVariable) (gpointer cond);
void (__stdcall * DeleteConditionVariable) (gpointer cond); /* fake */
@ -522,6 +525,12 @@ g_thread_xp_CallThisOnThreadExit (void)
typedef struct
{
CRITICAL_SECTION writer_lock;
gboolean ever_shared; /* protected by writer_lock */
/* below is only ever touched if ever_shared becomes true */
CRITICAL_SECTION atomicity;
GThreadXpWaiter *queued_writer; /* protected by atomicity lock */
gint num_readers; /* protected by atomicity lock */
} GThreadSRWLock;
static void __stdcall
@ -537,6 +546,9 @@ g_thread_xp_DeleteSRWLock (gpointer mutex)
if (lock)
{
if (lock->ever_shared)
DeleteCriticalSection (&lock->atomicity);
DeleteCriticalSection (&lock->writer_lock);
free (lock);
}
@ -564,6 +576,7 @@ g_thread_xp_get_srwlock (GThreadSRWLock * volatile *lock)
g_thread_abort (errno, "malloc");
InitializeCriticalSection (&result->writer_lock);
result->ever_shared = FALSE;
*lock = result;
LeaveCriticalSection (&g_thread_xp_lock);
@ -578,6 +591,21 @@ g_thread_xp_AcquireSRWLockExclusive (gpointer mutex)
GThreadSRWLock *lock = g_thread_xp_get_srwlock (mutex);
EnterCriticalSection (&lock->writer_lock);
if (lock->ever_shared)
{
GThreadXpWaiter *waiter = NULL;
EnterCriticalSection (&lock->atomicity);
if (lock->num_readers > 0)
lock->queued_writer = waiter = g_thread_xp_waiter_get ();
LeaveCriticalSection (&lock->atomicity);
if (waiter != NULL)
WaitForSingleObject (waiter->event, INFINITE);
lock->queued_writer = NULL;
}
}
static BOOLEAN __stdcall
@ -588,6 +616,21 @@ g_thread_xp_TryAcquireSRWLockExclusive (gpointer mutex)
if (!TryEnterCriticalSection (&lock->writer_lock))
return FALSE;
if (lock->ever_shared)
{
gboolean available;
EnterCriticalSection (&lock->atomicity);
available = lock->num_readers == 0;
LeaveCriticalSection (&lock->atomicity);
if (!available)
{
LeaveCriticalSection (&lock->writer_lock);
return FALSE;
}
}
return TRUE;
}
@ -603,6 +646,65 @@ g_thread_xp_ReleaseSRWLockExclusive (gpointer mutex)
LeaveCriticalSection (&lock->writer_lock);
}
static void
g_thread_xp_srwlock_become_reader (GThreadSRWLock *lock)
{
if G_UNLIKELY (!lock->ever_shared)
{
InitializeCriticalSection (&lock->atomicity);
lock->queued_writer = NULL;
lock->num_readers = 0;
lock->ever_shared = TRUE;
}
EnterCriticalSection (&lock->atomicity);
lock->num_readers++;
LeaveCriticalSection (&lock->atomicity);
}
static void __stdcall
g_thread_xp_AcquireSRWLockShared (gpointer mutex)
{
GThreadSRWLock *lock = g_thread_xp_get_srwlock (mutex);
EnterCriticalSection (&lock->writer_lock);
g_thread_xp_srwlock_become_reader (lock);
LeaveCriticalSection (&lock->writer_lock);
}
static BOOLEAN __stdcall
g_thread_xp_TryAcquireSRWLockShared (gpointer mutex)
{
GThreadSRWLock *lock = g_thread_xp_get_srwlock (mutex);
if (!TryEnterCriticalSection (&lock->writer_lock))
return FALSE;
g_thread_xp_srwlock_become_reader (lock);
LeaveCriticalSection (&lock->writer_lock);
return TRUE;
}
static void __stdcall
g_thread_xp_ReleaseSRWLockShared (gpointer mutex)
{
GThreadSRWLock *lock = g_thread_xp_get_srwlock (mutex);
EnterCriticalSection (&lock->atomicity);
lock->num_readers--;
if (lock->num_readers == 0 && lock->queued_writer)
SetEvent (lock->queued_writer->event);
LeaveCriticalSection (&lock->atomicity);
}
/* {{{2 CONDITION_VARIABLE emulation */
typedef struct
{
@ -738,6 +840,9 @@ g_thread_xp_init (void)
g_thread_xp_AcquireSRWLockExclusive,
g_thread_xp_TryAcquireSRWLockExclusive,
g_thread_xp_ReleaseSRWLockExclusive,
g_thread_xp_AcquireSRWLockShared,
g_thread_xp_TryAcquireSRWLockShared,
g_thread_xp_ReleaseSRWLockShared,
g_thread_xp_InitializeConditionVariable,
g_thread_xp_DeleteConditionVariable,
g_thread_xp_SleepConditionVariableSRW,
@ -786,6 +891,9 @@ g_thread_lookup_native_funcs (void)
GET_FUNC(AcquireSRWLockExclusive);
GET_FUNC(TryAcquireSRWLockExclusive);
GET_FUNC(ReleaseSRWLockExclusive);
GET_FUNC(AcquireSRWLockShared);
GET_FUNC(TryAcquireSRWLockShared);
GET_FUNC(ReleaseSRWLockShared);
GET_FUNC(InitializeConditionVariable);
GET_FUNC(SleepConditionVariableSRW);