bool PurgeableBuffer::makePurgeable(bool purgeable)
{
if (purgeable) {
if (m_state != NonVolatile)
return true;
int volatileGroup;
if (m_purgePriority == PurgeFirst)
volatileGroup = VM_VOLATILE_GROUP_0;
else if (m_purgePriority == PurgeMiddle)
volatileGroup = VM_VOLATILE_GROUP_4;
else
volatileGroup = VM_VOLATILE_GROUP_7;
int state = VM_PURGABLE_VOLATILE | volatileGroup;
// So apparently "purgeable" is the correct spelling and the API here is misspelled.
kern_return_t ret = vm_purgable_control(mach_task_self(), reinterpret_cast<vm_address_t>(m_data), VM_PURGABLE_SET_STATE, &state);
if (ret != KERN_SUCCESS) {
// If that failed we have no clue what state we are in so assume purged.
m_state = Purged;
return true;
}
m_state = Volatile;
return true;
}
if (m_state == NonVolatile)
return true;
if (m_state == Purged)
return false;
int state = VM_PURGABLE_NONVOLATILE;
kern_return_t ret = vm_purgable_control(mach_task_self(), reinterpret_cast<vm_address_t>(m_data), VM_PURGABLE_SET_STATE, &state);
if (ret != KERN_SUCCESS) {
// If that failed we have no clue what state we are in so assume purged.
m_state = Purged;
return false;
}
m_state = state & VM_PURGABLE_EMPTY ? Purged : NonVolatile;
return m_state == NonVolatile;
}
void
VolatileBuffer::Unlock()
{
MOZ_ASSERT(mLockCount > 0, "VolatileBuffer unlocked too many times!");
if (--mLockCount || OnHeap()) {
return;
}
int state = VM_PURGABLE_VOLATILE | VM_VOLATILE_GROUP_DEFAULT;
DebugOnly<kern_return_t> ret =
vm_purgable_control(mach_task_self(),
(vm_address_t)mBuf,
VM_PURGABLE_SET_STATE,
&state);
MOZ_ASSERT(ret == KERN_SUCCESS, "Failed to set buffer as purgable");
}
bool
VolatileBuffer::Lock(void** aBuf)
{
MOZ_ASSERT(mBuf, "Attempting to lock an uninitialized VolatileBuffer");
*aBuf = mBuf;
if (++mLockCount > 1 || OnHeap()) {
return true;
}
int state = VM_PURGABLE_NONVOLATILE;
kern_return_t ret =
vm_purgable_control(mach_task_self(),
(vm_address_t)mBuf,
VM_PURGABLE_SET_STATE,
&state);
return ret == KERN_SUCCESS && !(state & VM_PURGABLE_EMPTY);
}
bool PurgeableBuffer::wasPurged() const
{
if (m_state == NonVolatile)
return false;
if (m_state == Purged)
return true;
int state;
kern_return_t ret = vm_purgable_control(mach_task_self(), reinterpret_cast<vm_address_t>(m_data), VM_PURGABLE_GET_STATE, &state);
if (ret != KERN_SUCCESS) {
// If that failed we have no clue what state we are in so assume purged.
m_state = Purged;
return true;
}
if (state & VM_PURGABLE_EMPTY) {
m_state = Purged;
return true;
}
return false;
}
