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memory: cleanup the locking code

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cleanup and fix the locking code
This commit is contained in:
Wim Taymans 2012-07-03 12:16:19 +02:00
parent 93f279cd5a
commit 70c1513eac
1 changed files with 38 additions and 28 deletions
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66
gst/gstmemory.c
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@ -520,26 +520,31 @@ gst_memory_lock (GstMemory * mem, GstLockFlags flags)
access_mode = flags & FLAG_MASK;
do {
state = g_atomic_int_get (&mem->state);
if (flags == GST_LOCK_FLAG_EXCLUSIVE) {
newstate = state = g_atomic_int_get (&mem->state);
GST_CAT_TRACE (GST_CAT_MEMORY, "lock %p: state %08x, access_mode %d",
mem, state, access_mode);
if (access_mode & GST_LOCK_FLAG_EXCLUSIVE) {
/* shared ref */
newstate = state + SHARE_ONE;
flags &= ~GST_LOCK_FLAG_EXCLUSIVE;
newstate += SHARE_ONE;
access_mode &= ~GST_LOCK_FLAG_EXCLUSIVE;
}
/* shared counter > 1 and write access */
if (state > SHARE_ONE && flags & GST_LOCK_FLAG_WRITE)
goto lock_failed;
if ((state & LOCK_FLAG_MASK) == 0) {
/* nothing mapped, set access_mode and refcount */
newstate = state | LOCK_ONE | access_mode;
} else {
/* access_mode must match */
if ((state & access_mode) != access_mode)
goto lock_failed;
if (access_mode) {
if ((state & LOCK_FLAG_MASK) == 0) {
/* shared counter > 1 and write access */
if (state > SHARE_ONE && access_mode & GST_LOCK_FLAG_WRITE)
goto lock_failed;
/* nothing mapped, set access_mode */
newstate |= access_mode;
} else {
/* access_mode must match */
if ((state & access_mode) != access_mode)
goto lock_failed;
}
/* increase refcount */
newstate = state + LOCK_ONE;
newstate += LOCK_ONE;
}
} while (!g_atomic_int_compare_and_exchange (&mem->state, state, newstate));
@ -547,7 +552,7 @@ gst_memory_lock (GstMemory * mem, GstLockFlags flags)
lock_failed:
{
GST_CAT_DEBUG (GST_CAT_MEMORY, "lock failed %p: state %d, access_mode %d",
GST_CAT_DEBUG (GST_CAT_MEMORY, "lock failed %p: state %08x, access_mode %d",
mem, state, access_mode);
return FALSE;
}
@ -565,24 +570,29 @@ gst_memory_unlock (GstMemory * mem, GstLockFlags flags)
{
gint access_mode, state, newstate;
access_mode = flags & 3;
access_mode = flags & FLAG_MASK;
do {
state = g_atomic_int_get (&mem->state);
if (flags == GST_LOCK_FLAG_EXCLUSIVE) {
newstate = state = g_atomic_int_get (&mem->state);
GST_CAT_TRACE (GST_CAT_MEMORY, "unlock %p: state %08x, access_mode %d",
mem, state, access_mode);
if (access_mode & GST_LOCK_FLAG_EXCLUSIVE) {
/* shared counter */
g_return_if_fail (state >= SHARE_ONE);
newstate = state - SHARE_ONE;
flags &= ~GST_LOCK_FLAG_EXCLUSIVE;
access_mode &= ~GST_LOCK_FLAG_EXCLUSIVE;
}
g_return_if_fail ((state & access_mode) == access_mode);
/* decrease the refcount */
newstate = state - LOCK_ONE;
/* last refcount, unset access_mode */
if ((newstate & LOCK_FLAG_MASK) == access_mode)
newstate = state & ~LOCK_FLAG_MASK;
if (access_mode) {
g_return_if_fail ((state & access_mode) == access_mode);
/* decrease the refcount */
newstate -= LOCK_ONE;
/* last refcount, unset access_mode */
if ((newstate & LOCK_FLAG_MASK) == access_mode)
newstate &= ~LOCK_FLAG_MASK;
}
} while (!g_atomic_int_compare_and_exchange (&mem->state, state, newstate));
}