def fetch_id(self, storable):
"""
Fetch an ID for this object, if possible.
"Predict" the id for this storable. If GUIDs are being used,
this method will fetch a new GUID, set it, and return
that ID immediately (assuming that this object will ultimately
be saved with that ID).
If GUIDs are not being used, this method will return 0 if
this is an unsaved object. It's not possible to use "predictive"
IDs in that case.
@see: L{IFactory.fetch_id()}
@param storable: the object whose ID you wish to fetch
@type storable: L{storable.Storable}
@returns: the item's id, or 0
@rtype: int
@raises LookupError: if no factory has been registered for this Storable's table
"""
id = storable.get_id()
if(id == 0):
table = storable.get_table()
if not(self.has_factory(table)):
raise LookupError('There is no factory registered for the table `%s`' % table)
factory = self.get_factory(table)
use_locks = (not bool(self.req)) or self.req.app.config.get('use_db_locks', True)
new_id = factory.get_id(use_locks=use_locks)
storable.set_id(new_id, set_old=False)
return new_id
return id
def _save(self, storable, factory):
"""
Internal function that is responsible for doing the
actual saving.
"""
if not(storable.is_dirty()):
return False
table = storable.get_table()
data = storable.get_data()
locks_allowed = (not bool(self.req)) or self.req.app.config.get('use_db_locks', True)
use_locks = False
primary_key = factory.get_primary_key()
if(storable.is_new()):
if(factory.uses_guids()):
data[primary_key] = self.fetch_id(storable)
elif(locks_allowed):
use_locks = True
self.pool.runOperation('LOCK TABLES `%s` WRITE' % table)
else:
raise RuntimeError("Broken program logic is trying to lock an unlockable database.")
query = sql.build_insert(table, data)
else:
query = sql.build_update(table, data, {primary_key:storable.get_id()})
self.log(query)
try:
self.pool.runOperation(query)
if not(factory.uses_guids()):
if not(storable.get_id()):
rows = self.pool.runQuery('SELECT MAX(%s) AS `id` FROM `%s`' % (primary_key, table))
new_id = rows[0]['id']
storable.set_id(new_id)
finally:
if(use_locks):
self.pool.runOperation('UNLOCK TABLES')
storable.clean()
storable.set_new(False)
storable.set_factory(factory)
return True
