def __init__(self, trusted_basis):
"""
Initializes the IntegrityManager with a trusted basis.
"""
self.trusted_basis = trusted_basis
self.proofmanager = ProofManager(False)
self.logger = logging.getLogger("FR." + self.__class__.__name__)
def __init__(self, trusted_basis):
'''Initializes the IntegrityManager with a trusted basis.
'''
self.trusted_basis = trusted_basis
self.proofmanager = ProofManager(False)
self.logger = logging.getLogger("FR." + self.__class__.__name__)
class IntegrityManager(object):
'''IntegrityManager handles integrity checks for the client.
It must be initialized with a trusted beginning basis; after then it
can check proofs and store operations.
It can 'check commit results', checking a given server basis.
'''
def __init__(self, trusted_basis):
'''Initializes the IntegrityManager with a trusted basis.
'''
self.trusted_basis = trusted_basis
self.proofmanager = ProofManager(False)
self.logger = logging.getLogger("FR." + self.__class__.__name__)
def addOperation(self, verb, pathname, proof, filehash=None):
'''Adds the described operation to the operation register,
checking its correctness and the integrity of the related
information.
@verb: describes the operation
@pathname: the target pathname of the operation
@filehash: None by default, it's used in insertions and updatings.
@proof: the Proof recieved by the server.
raise: MalformedProofException if proof is somehow broken.
raise: UnrelatedProofException if proof is fraudolent or not
related to specified pathname.
raise: WrongBasisFromProofException if basis doesn't match.
raise: PathnameTypeException if given pathname is not a unicode
object
'''
self._checkUnicodePathname(pathname)
# This must be done before checking correctness.
proof.operation = verb
proof.pathname = pathname
operation_basis = self.proofmanager.addOperation(proof, filehash)
if operation_basis != self.trusted_basis:
raise WrongBasisFromProofException(
"Basis mismatch between trusted-basis and proof-basis!", proof,
pathname, operation_basis)
def clear(self):
self.proofmanager.flushOperationList()
self.trusted_basis = None
def getCurrentBasis(self):
'''Returns currently stored trusted basis.
'''
return self.trusted_basis
def setCurrentBasis(self, basis):
'''Sets currently stored trusted basis.
'''
self.trusted_basis = basis
def isCurrent(self, basis):
return basis == self.trusted_basis
def checkCommitResult(self, server_basis):
'''Verifies that server ADS matches with the client ADS after
committing previously added operations.
If no operations have been scheduled, previous trusted basis is
used for comparison.
raise: UnexpectedBasisComputationException if anything goes
wrong while computing basis.
raise: WrongBasisAfterUpdatingException if after basis
computation, it is different by given server basis.
'''
# It's important to flush operations in any case and reassign basis
# only if everything it's ok.
try:
self._checkBasis(server_basis)
finally:
self.proofmanager.flushOperationList()
def _checkBasis(self, server_basis):
'''Actually do the dirty job: computes basis, compares it to
given one, update the current trusted basis.
raise: UnexpectedBasisComputationException
raise: WrongBasisAfterUpdatingException
'''
candidate_basis = self.getCandidateBasis()
# The time of truth!
if not candidate_basis == server_basis:
raise WrongBasisAfterUpdatingException(
"Basis mismatch between computed-basis and server-basis!",
candidate_basis)
self.trusted_basis = candidate_basis
def getCandidateBasis(self):
'''
Returns the client-basis that must be compared to the server basis.
raise: UnexpectedBasisComputationException
'''
if len(self.proofmanager.getPendingOperations()) == 0:
return self.trusted_basis
try:
computed_basis = self.proofmanager.getBasis()
except Exception as e:
raise UnexpectedBasisComputationException(
"Unexpected error during basis computation: %s" % e.message)
return computed_basis
def _checkUnicodePathname(self, pathname):
'''Checks if a pathname is an unicode object.
It does not return anything, but raise PathnameTypeException.
'''
try:
assert pathname.__class__.__name__ == "unicode"
except:
raise PathnameTypeException(
"Pathname %s is not a unicode object!" % (repr(pathname)),
pathname.__class__.__name__)
class IntegrityManager(object):
"""
IntegrityManager handles integrity checks for the client.
It must be initialized with a trusted beginning basis; after then it can check
proofs and store operations.
It can 'check commit results', checking a given server basis.
"""
def __init__(self, trusted_basis):
"""
Initializes the IntegrityManager with a trusted basis.
"""
self.trusted_basis = trusted_basis
self.proofmanager = ProofManager(False)
self.logger = logging.getLogger("FR." + self.__class__.__name__)
def addOperation(self, verb, pathname, proof, filehash=None):
"""
Adds the described operation to the operation register, checking its correctness and
the integrity of the related information.
@verb: describes the operation
@pathname: the target pathname of the operation
@filehash: None by default, it's used in insertions and updatings.
@proof: the Proof recieved by the server.
raise: MalformedProofException if proof is somehow broken.
raise: UnrelatedProofException if proof is fraudolent or not related to specified pathname.
raise: WrongBasisFromProofException if basis doesn't match.
raise: PathnameTypeException if given pathname is not a unicode object
"""
self._checkUnicodePathname(pathname)
# This must be done before checking correctness.
proof.operation = verb
proof.pathname = pathname
operation_basis = self.proofmanager.addOperation(proof, filehash)
if operation_basis != self.trusted_basis:
raise WrongBasisFromProofException(
"Basis mismatch between trusted-basis and proof-basis!", proof, pathname, operation_basis
)
def getCurrentBasis(self):
"""
Returns currently stored trusted basis.
"""
return self.trusted_basis
def setCurrentBasis(self, basis):
"""
Sets currently stored trusted basis.
"""
self.trusted_basis = basis
def isCurrent(self, basis):
return basis == self.trusted_basis
def checkCommitResult(self, server_basis):
"""
Verifies that server ADS matches with the client ADS after committing previously
added operations. If no operations have been scheduled, previous trusted basis is used for comparison.
raise: UnexpectedBasisComputationException if anything goes wrong while computing basis.
raise: WrongBasisAfterUpdatingException if after basis computation, it is different by given server basis. And THIS is critical!
"""
# It's important to flush operations in any case and reassign basis only if everything it's ok.
try:
self._checkBasis(server_basis)
except Exception as e:
raise e
finally:
self.proofmanager.flushOperationList()
def _checkBasis(self, server_basis):
"""
Actually do the dirty job: computes basis, compares it to given one, update the current
trusted basis, raise Exceptions if anything goes wrong.
raise: UnexpectedBasisComputationException
raise: WrongBasisAfterUpdatingException
"""
candidate_basis = self.getCandidateBasis()
# The time of truth!
if not candidate_basis == server_basis:
raise WrongBasisAfterUpdatingException(
"Basis mismatch between computed-basis and server-basis!", candidate_basis
)
self.trusted_basis = candidate_basis
def getCandidateBasis(self):
"""
Returns the client-basis that must be compared to the server basis.
raise: UnexpectedBasisComputationException
"""
if len(self.proofmanager.getPendingOperations()) == 0:
return self.trusted_basis
try:
computed_basis = self.proofmanager.getBasis()
except Exception as e:
raise UnexpectedBasisComputationException("Unexpected error during basis computation: %s" % e.message)
return computed_basis
def _checkUnicodePathname(self, pathname):
"""
Checks if a pathname is an unicode object.
It does not return anything, but
-raise PathnameTypeException."""
try:
assert pathname.__class__.__name__ == "unicode"
except:
raise PathnameTypeException(
"Pathname %s is not a unicode object!" % (repr(pathname)), pathname.__class__.__name__
)
