"""Base class for SharedKeyDB and VerifierDB."""

import anydbm

import thread

class BaseDB:

def __init__(self, filename, type):

self.type = type

self.filename = filename

if self.filename:

self.db = None

else:

self.db = {}

self.lock = thread.allocate_lock()

def create(self):

"""Create a new on-disk database.

@raise anydbm.error: If there's a problem creating the database.

"""

if self.filename:

self.db = anydbm.open(self.filename, "n") #raises anydbm.error

self.db["--Reserved--type"] = self.type

self.db.sync()

else:

self.db = {}

def open(self):

"""Open a pre-existing on-disk database.

@raise anydbm.error: If there's a problem opening the database.

@raise ValueError: If the database is not of the right type.

"""

if not self.filename:

raise ValueError("Can only open on-disk databases")

self.db = anydbm.open(self.filename, "w") #raises anydbm.error

try:

if self.db["--Reserved--type"] != self.type:

raise ValueError("Not a %s database" % self.type)

except KeyError:

raise ValueError("Not a recognized database")

def __getitem__(self, username):

if self.db == None:

raise AssertionError("DB not open")

self.lock.acquire()

try:

valueStr = self.db[username]

finally:

self.lock.release()

return self._getItem(username, valueStr)

def __setitem__(self, username, value):

if self.db == None:

raise AssertionError("DB not open")

valueStr = self._setItem(username, value)

self.lock.acquire()

try:

self.db[username] = valueStr

if self.filename:

self.db.sync()

finally:

self.lock.release()

def __delitem__(self, username):

if self.db == None:

raise AssertionError("DB not open")

self.lock.acquire()

try:

del(self.db[username])

if self.filename:

self.db.sync()

finally:

self.lock.release()

def __contains__(self, username):

"""Check if the database contains the specified username.

@type username: str

@param username: The username to check for.

@rtype: bool

@return: True if the database contains the username, False

otherwise.

"""

if self.db == None:

raise AssertionError("DB not open")

self.lock.acquire()

try:

return self.db.has_key(username)

finally:

self.lock.release()

def check(self, username, param):

value = self.__getitem__(username)

return self._checkItem(value, username, param)

def keys(self):

"""Return a list of usernames in the database.

@rtype: list

@return: The usernames in the database.

"""

if self.db == None:

raise AssertionError("DB not open")

self.lock.acquire()

try:

usernames = self.db.keys()

finally:

self.lock.release()

usernames = [u for u in usernames if not u.startswith("--Reserved--")]

return usernames