def _check_current_holder(self, session_id=None):
if not session_id:
session_id = self.function.session.oid
q = "SELECT 1 "
q += " FROM rpcc_mutex "
q += "WHERE id=:mutex "
q += " AND holder_session=:sesn "
ret = list(self.db.get(q, mutex=self.mutex_id, sesn=session_id))
if len(ret) == 0:
raise default_error.ExtMutexNotHeldError()
def create_variable(self, name, typ, session=None):
self._check_current_holder(session)
q = "INSERT INTO rpcc_mutex_var (mutex_id, name, typ) "
q += " VALUES (:mtx, :name, :typ) "
try:
affected = self.db.put(q, mtx=self.mutex_id, name=name, typ=typ)
except database.IntegrityError as _e:
raise default_error.ExtMutexVariableAlreadyExistsError()
if affected == 0:
raise default_error.ExtMutexNotHeldError()
def get_variable_names(self, typ, session=None):
# Mutex hold check is implicit in query
if not session:
session = self.function.session.oid
q = "SELECT m.id, v.name "
q += " FROM rpcc_mutex m LEFT OUTER JOIN rpcc_mutex_var v "
q += " ON (m.id=v.mutex_id "
q += " AND m.holder_session=:sesn "
q += " AND v.typ=:typ) "
ret = list(self.db.get(q, sesn=session, typ=typ))
# No rows returned -> mutex not held
if len(ret) == 0:
raise default_error.ExtMutexNotHeldError()
# One or more rows -> non-null values are variable names of the
# specified type.
return [var for (_, var) in ret if var is not None]
def do(self):
if not self.mutex.release(self.force):
raise default_error.ExtMutexNotHeldError()