def breakup_expression(expression, entry):
inputs = [p.name for p in raw_encode_params.get_params(entry) if p.direction == p.IN]
constant, components = solve_expression(expression, expression, entry, raw_decode_params, inputs)
try:
constant = constant.evaluate({})
except UndecodedReferenceError:
pass
return constant, components
def _solve(result_expr, sequence, param_name, expression_params):
constant, components = solve_expression(result_expr, sequence.value, sequence, expression_params.expression_params, [])
if len(components) == 1:
reference, expression, inverted = components[0]
if reference.name == param_name:
return inverted.evaluate({})
else:
logging.warning("Expected to solve reference to '%s', but "
"found '%s'! Skipping constraint." %
(param_name, reference.name))
else:
logging.warning("Found multiple unknowns when solving '%s'! Skipping constraint." % sequence.value)
def _are_expression_inputs_available(expr, entry):
"""Check to see if all of the inputs to an expression are available."""
names = [p.name for p in encode_params.get_params(entry) if p.direction == p.IN]
result = ReferenceExpression('result')
inputs = [p.name for p in encode_params.get_params(entry) if p.direction == p.IN]
constant, components = solve_expression(result, expr, entry, raw_decode_params, inputs)
for ref, expr, inverted in components:
if variable(ref.name) not in names:
# The expression references an item that isn't being passed in.
return False
return True
def _is_length_known(entry):
inputs = [p.name for p in raw_encode_params.get_params(entry) if p.direction == p.IN]
constant, components = solve_expression(entry.length, entry.length, entry, raw_decode_params, inputs)
return len(components) == 0