# Return a hash of {group_uuid: perm_hash} where perm_hash[:read]
# and perm_hash[:write] are true if this user can read and write
# objects owned by group_uuid.
+ #
+ # The permission graph is built by repeatedly enumerating all
+ # permission links reachable from self.uuid, and then calling
+ # search_permissions
def group_permissions
Rails.cache.fetch "groups_for_user_#{self.uuid}" do
permissions_from = {}
todo = {self.uuid => true}
done = {}
+ # Build the equivalence class of permissions starting with
+ # self.uuid. On each iteration of this loop, todo contains
+ # the next set of uuids in the permission equivalence class
+ # to evaluate.
while !todo.empty?
lookup_uuids = todo.keys
lookup_uuids.each do |uuid| done[uuid] = true end
todo = {}
newgroups = []
+ # include all groups owned by the current set of uuids.
Group.where('owner_uuid in (?)', lookup_uuids).each do |group|
newgroups << [group.owner_uuid, group.uuid, 'can_manage']
end
+ # add any permission links from the current lookup_uuids to a
+ # User or Group.
Link.where('tail_uuid in (?) and link_class = ? and (head_uuid like ? or head_uuid like ?)',
lookup_uuids,
'permission',