/*! Locks the monitor and/or increments lock counter;
* throws EALREADY if the monitor is already locked */
void lock()
{
gu::Lock lock(mutex_);
assert(locked_ >= 0);
if (locked_ > 0)
{
log_warn << "Attempt to lock an already locked monitor.";
locked_++;
if (locked_ > 0)
{
gu_throw_error(EALREADY);
}
else
{
gu_throw_fatal << "More than " << (locked_ - 1)
<< " concurrent locks.";
}
}
if (last_entered_ != -1)
{
while (drain_seqno_ != LLONG_MAX) lock.wait(cond_);
/*! @note: last_entered_ probably changed since last check */
drain_common(last_entered_, lock);
/* would_block() should return true when drain_seqno_ is set
* so the monitor should be totally empty at this point. */
}
locked_ = 1;
log_debug << "Locked local monitor at " << (last_left_ + 1);
}
void drain(wsrep_seqno_t seqno)
{
gu::Lock lock(mutex_);
while (drain_seqno_ != GU_LLONG_MAX)
{
lock.wait(cond_);
}
drain_common(seqno, lock);
// there can be some stale canceled entries
update_last_left();
drain_seqno_ = GU_LLONG_MAX;
cond_.broadcast();
}
void set_initial_position(wsrep_seqno_t seqno)
{
gu::Lock lock(mutex_);
if (last_entered_ == -1 || seqno == -1)
{
// first call or reset
last_entered_ = last_left_ = seqno;
}
else
{
// drain monitor up to seqno but don't reset last_entered_
// or last_left_
drain_common(seqno, lock);
drain_seqno_ = GU_LLONG_MAX;
}
if (seqno != -1)
{
const size_t idx(indexof(seqno));
process_[idx].wait_cond_.broadcast();
}
}
