class Query(Composer):
'''
Finds a match for the LHS.
'''
def __init__(self, LHS):
'''
Finds a match for the LHS.
@param LHS: The pre-condition pattern (LHS + NACs).
'''
super(Query, self).__init__()
self.M = Matcher(condition=LHS, max=1)
self.I = Iterator(max_iterations=1)
def packet_in(self, packet):
self.exception = None
self.is_success = False
# Match
packet = self.M.packet_in(packet)
if not self.M.is_success:
self.exception = self.M.exception
return packet
# Choose the only match
packet = self.I.packet_in(packet)
if not self.I.is_success:
# Clean the packet: required since there is no Rewriter in a Query
if len(packet.match_sets[self.I.condition].matches) == 0:
del packet.match_sets[self.I.condition]
self.exception = self.I.exception
return packet
# Output success packet
self.is_success = True
return packet
class LRule(Composer):
'''
Applies an inner rule for each match of the LHS.
'''
def __init__(self, LHS, inner_rule, max_iterations=INFINITY):
'''
Applies an inner rule for each match of the LHS.
@param LHS: The pre-condition pattern (LHS + NACs).
@param inner_rule: The rule to apply in the loop.
@param max_iterations: The maximum number of matches of the LHS.
'''
super(LRule, self).__init__()
self.M = Matcher(condition=LHS, max=max_iterations)
self.I = Iterator(max_iterations=max_iterations)
self.inner_rule = inner_rule
def packet_in(self, packet):
self.exception = None
self.is_success = False
# Match
packet = self.M.packet_in(packet)
if not self.M.is_success:
self.exception = self.M.exception
return packet
# Choose the first match
packet = self.I.packet_in(packet)
if not self.I.is_success:
self.exception = self.I.exception
return packet
while True:
# Apply the inner rule
packet = self.inner_rule.packet_in(packet)
if not self.inner_rule.is_success:
if self.inner_rule.exception:
self.exception = self.inner_rule.exception
return packet
# Clean the packet: required since there is no Rewriter in a Query
if len(packet.match_sets[self.I.condition].matches) == 0:
del packet.match_sets[self.I.condition]
# Choose another match
packet = self.I.next_in(packet)
# No more iterations are left
if not self.I.is_success:
if self.I.exception:
self.exception = self.I.exception
else:
# Output success packet
self.is_success = True
return packet
class ARule(Composer):
"""
Applies the transformation on one match.
"""
def __init__(self, LHS, RHS):
"""
Applies the transformation on one match.
@param LHS: The pre-condition pattern (LHS + NACs).
@param RHS: The post-condition pattern (RHS).
"""
super(ARule, self).__init__()
self.M = Matcher(condition=LHS, max=1)
self.I = Iterator(max_iterations=1)
self.W = Rewriter(condition=RHS)
def packet_in(self, packet):
self.exception = None
self.is_success = False
# Match
packet = self.M.packet_in(packet)
if not self.M.is_success:
self.exception = self.M.exception
return packet
# Choose the only match
packet = self.I.packet_in(packet)
if not self.I.is_success:
self.exception = self.I.exception
return packet
# Rewrite
packet = self.W.packet_in(packet)
if not self.W.is_success:
self.exception = self.W.exception
return packet
# Output success packet
self.is_success = True
return packet