def _update_entity(self, extent_name, oid, fields, related_entities,
rev=None):
"""Update an existing entity in an extent.
- `extent_name`: Name of the extent to create a new entity in.
- `oid`: OID of the entity to update.
- `fields`: Dictionary of field_name:field_value mappings to change,
where each field_value is the value to be stored in the database, as
returned by a field instance's `_dump` method.
- `related_entities`: Dictionary of field_name:related_entity_set
mappings, where each related_entity_set is the set of entities
stored in the field's structure, as returned by a field instance's
`_entities_in_value` method.
- `rev`: (optional) Specific revision to update the entity to.
"""
# XXX: Could be optimized to update mappings only when
# necessary.
entity_classes = self._entity_classes
entity_map, extent_map = self._entity_extent_map(extent_name, oid)
field_name_id = extent_map['field_name_id']
entity_field_ids = extent_map['entity_field_ids']
extent_name_id = self._extent_name_id
extent_maps_by_id = self._extent_maps_by_id
indices_added = []
indices_removed = []
new_links = []
links_created = []
links_deleted = []
ia_append = indices_added.append
ir_append = indices_removed.append
nl_append = new_links.append
lc_append = links_created.append
ld_append = links_deleted.append
BTree = self._BTree
try:
# Get old values for use in a potential inversion.
old_fields = self._entity_fields(extent_name, oid)
old_related_entities = self._entity_related_entities(
extent_name, oid)
old_rev = entity_map['rev']
# Dereference entities.
for name, value in fields.items():
field_id = field_name_id[name]
if field_id in entity_field_ids:
if isinstance(value, Placeholder):
# Dereference entity.
other_extent_id = value.extent_id
other_oid = value.oid
value = (other_extent_id, other_oid)
nl_append((field_id, other_extent_id, other_oid))
elif len(related_entities.get(name, [])) > 1:
msg = (
'Field values with multiple entities are not '
'supported by format 1 Schevo databases.'
)
raise UnsupportedFieldType(reason)
fields[name] = value
# Get fields, and set UNASSIGNED for any fields that are
# new since the last time the entity was stored.
fields_by_id = entity_map['fields']
all_field_ids = set(extent_map['field_id_name'].iterkeys())
new_fields = all_field_ids - set(fields_by_id.iterkeys())
fields_by_id.update(dict(
(field_id, UNASSIGNED) for field_id in new_fields))
# Remove existing index mappings.
indices = extent_map['indices']
for index_spec in indices.iterkeys():
field_values = tuple(fields_by_id[field_id]
for field_id in index_spec)
# Find out if the index has been relaxed.
relaxed_specs = self._relaxed[extent_name]
if index_spec in relaxed_specs:
txns, relaxed = relaxed_specs[index_spec]
else:
relaxed = None
_index_remove(extent_map, index_spec, oid, field_values)
ir_append((extent_map, index_spec, relaxed, oid, field_values))
# Delete links from this entity to other entities.
referrer_extent_id = extent_name_id[extent_name]
for referrer_field_id in entity_field_ids:
other_value = fields_by_id[referrer_field_id]
if isinstance(other_value, tuple):
# Remove the link to the other entity.
other_extent_id, other_oid = other_value
link_key = (referrer_extent_id, referrer_field_id)
other_extent_map = extent_maps_by_id[other_extent_id]
other_entity_map = other_extent_map['entities'][other_oid]
links = other_entity_map['links']
other_links = links[link_key]
del other_links[oid]
other_entity_map['link_count'] -= 1
ld_append((other_entity_map, links, link_key, oid))
# Create ephemeral fields for creating new index mappings.
new_fields = dict(fields_by_id)
for name, value in fields.iteritems():
new_fields[field_name_id[name]] = value
# Create new index mappings.
for index_spec in indices.iterkeys():
field_values = tuple(new_fields[field_id]
for field_id in index_spec)
# Find out if the index has been relaxed.
relaxed_specs = self._relaxed[extent_name]
if index_spec in relaxed_specs:
txns, relaxed = relaxed_specs[index_spec]
else:
relaxed = None
_index_add(extent_map, index_spec, relaxed, oid, field_values,
BTree)
ia_append((extent_map, index_spec, oid, field_values))
# Update links from this entity to another entity.
referrer_extent_id = extent_name_id[extent_name]
for referrer_field_id, other_extent_id, other_oid in new_links:
other_extent_map = extent_maps_by_id[other_extent_id]
try:
other_entity_map = other_extent_map['entities'][other_oid]
except KeyError:
field_id_name = extent_map['field_id_name']
field_name = field_id_name[referrer_field_id]
other_extent_map = extent_maps_by_id[other_extent_id]
other_extent_name = other_extent_map['name']
raise error.EntityDoesNotExist(
other_extent_name, field_name=field_name)
# Add a link to the other entity.
links = other_entity_map['links']
link_key = (referrer_extent_id, referrer_field_id)
if link_key not in links: # XXX Should already be there.
links[link_key] = BTree()
links[link_key][oid] = None
other_entity_map['link_count'] += 1
lc_append((other_entity_map, links, link_key, oid))
# Update actual fields.
for name, value in fields.iteritems():
fields_by_id[field_name_id[name]] = value
if rev is None:
entity_map['rev'] += 1
else:
entity_map['rev'] = rev
# Allow inversion of this operation.
self._append_inversion(
self._update_entity, extent_name, oid, old_fields,
old_related_entities, old_rev)
# Keep track of changes.
append_change = self._append_change
append_change(UPDATE, extent_name, oid)
except:
# Revert changes made during update attempt.
for _e, _i, _o, _f in indices_added:
_index_remove(_e, _i, _o, _f)
for _e, _i, _r, _o, _f in indices_removed:
_index_add(_e, _i, _r, _o, _f, BTree)
for other_entity_map, links, link_key, oid in links_created:
del links[link_key][oid]
other_entity_map['link_count'] -= 1
for other_entity_map, links, link_key, oid in links_deleted:
links[link_key][oid] = None
other_entity_map['link_count'] += 1
raise
def _create_entity(self, extent_name, fields, related_entities,
oid=None, rev=None):
"""Create a new entity in an extent; return the oid.
- `extent_name`: Name of the extent to create a new entity in.
- `fields`: Dictionary of field_name:field_value mappings, where
each field_value is the value to be stored in the database, as
returned by a field instance's `_dump` method.
- `related_entities`: Dictionary of field_name:related_entity_set
mappings, where each related_entity_set is the set of entities
stored in the field's structure, as returned by a field
instance's `_entities_in_value` method.
- `oid`: (optional) Specific OID to create the entity as; used
for importing data, e.g. from an XML document.
- `rev`: (optional) Specific revision to create the entity as; see
`oid`.
"""
extent_map = self._extent_map(extent_name)
entities = extent_map['entities']
old_next_oid = extent_map['next_oid']
field_name_id = extent_map['field_name_id']
entity_field_ids = extent_map['entity_field_ids']
extent_name_id = self._extent_name_id
extent_maps_by_id = self._extent_maps_by_id
indices_added = []
ia_append = indices_added.append
links_created = []
lc_append = links_created.append
BTree = self._BTree
PDict = self._PDict
try:
if oid is None:
oid = extent_map['next_oid']
extent_map['next_oid'] += 1
if rev is None:
rev = 0
if oid in entities:
raise error.EntityExists(extent_name, oid)
# Create dict with field-id:field-value items.
fields_by_id = PDict()
new_links = []
nl_append = new_links.append
for name, value in fields.iteritems():
field_id = field_name_id[name]
# Handle entity reference fields.
if field_id in entity_field_ids:
if isinstance(value, Placeholder):
# Dereference entity.
other_extent_id = value.extent_id
other_oid = value.oid
value = (other_extent_id, other_oid)
nl_append((field_id, other_extent_id, other_oid))
elif len(related_entities.get(name, [])) > 1:
msg = (
'Field values with multiple entities are not '
'supported by format 1 Schevo databases.'
)
raise error.UnsupportedFieldType(reason)
fields_by_id[field_id] = value
# Make sure fields that weren't specified are set to
# UNASSIGNED.
setdefault = fields_by_id.setdefault
for field_id in field_name_id.itervalues():
setdefault(field_id, UNASSIGNED)
# Update index mappings.
indices = extent_map['indices']
for index_spec in indices.iterkeys():
field_values = tuple(fields_by_id[field_id]
for field_id in index_spec)
# Find out if the index has been relaxed.
relaxed_specs = self._relaxed[extent_name]
if index_spec in relaxed_specs:
txns, relaxed = relaxed_specs[index_spec]
else:
relaxed = None
_index_add(extent_map, index_spec, relaxed, oid, field_values,
BTree)
ia_append((extent_map, index_spec, oid, field_values))
# Update links from this entity to another entity.
referrer_extent_id = extent_name_id[extent_name]
for referrer_field_id, other_extent_id, other_oid in new_links:
other_extent_map = extent_maps_by_id[other_extent_id]
try:
other_entity_map = other_extent_map['entities'][other_oid]
except KeyError:
field_id_name = extent_map['field_id_name']
field_name = field_id_name[referrer_field_id]
other_extent_map = extent_maps_by_id[other_extent_id]
other_extent_name = other_extent_map['name']
raise error.EntityDoesNotExist(
other_extent_name, field_name=field_name)
# Add a link to the other entity.
links = other_entity_map['links']
link_key = (referrer_extent_id, referrer_field_id)
if link_key not in links: # XXX Should already be there.
links[link_key] = BTree()
links[link_key][oid] = None
other_entity_map['link_count'] += 1
lc_append((other_entity_map, links, link_key, oid))
# Create the actual entity.
entity_map = entities[oid] = PDict()
entity_map['rev'] = rev
entity_map['fields'] = fields_by_id
# XXX flesh out links based on who is capable of linking
# to this one.
entity_map['link_count'] = 0
entity_map['links'] = PDict()
extent_map['len'] += 1
# Allow inversion of this operation.
self._append_inversion(self._delete_entity, extent_name, oid)
# Keep track of changes.
append_change = self._append_change
append_change(CREATE, extent_name, oid)
return oid
except:
# Revert changes made during create attempt.
for _e, _i, _o, _f in indices_added:
_index_remove(_e, _i, _o, _f)
for other_entity_map, links, link_key, oid in links_created:
del links[link_key][oid]
other_entity_map['link_count'] -= 1
extent_map['next_oid'] = old_next_oid
raise
