def read_until_string(self, str):
"""Pretend to read from the port until the given string is
detected or the read times out. Return the previously recorded
result.
"""
timestamp, parameters = self.next_log("read-until")
# extract the argument, result, and status
status = None
if parameters.endswith("]"):
pos = parameters.rindex(" [")
status = parameters[pos + 2:-1]
parameters = parameters[:pos]
log_str, log_result = [eval(p) for p in parameters.split(" = ", 1)]
if log_str != str:
warn("%d: read-until(%r) != log(%r)" %
(self.line_number, str, log_str))
if self.mimic_timing:
time.sleep(timestamp - self.timestamp)
self.timestamp = timestamp
if status == "interval-expired":
raise exception.IntervalTimeout(response=log_result)
if status == "timeout-expired":
raise exception.ReadTimeout(response=log_result)
return log_result
def read_until_string(self, str):
"""Read from the port until the given string is detected
or the read times out, whichever comes first.
str -- the string to await
Raises an IntervalTimeout exception if the polling interval
expires without receiving any data. Raises a ReadTimeout
exception if the read timout expires before the given string
is encountered. See set_timeout for more details.
"""
buffer = ""
interval = self.interval
try:
while True:
remaining = self.timeout - time.time()
if (remaining <= 0):
raise exception.ReadTimeout(response=buffer)
# make sure the read() doesn't go beyond the timeout
if remaining < interval and interval >= self.MAX_READ_OVERRUN:
interval = remaining / 2.0
self.port.setTimeout(interval)
# read() times out after the polling interval set by set_timeout()
c = self.port.read(1)
if len(c) == 0 and interval == self.interval:
# stop if the read timed out without data
raise exception.IntervalTimeout(response=buffer)
# FIXME: move 0x00 test to ELM327
if c == '\x00':
continue # per note on p.6 of ELM327 data sheet
buffer += c
if (buffer.endswith(str)):
break
finally:
# if we temporarily dialed down the port's timeout to avoid
# galloping past the timeout, restore it to its previous value
if interval != self.interval:
self.port.setTimeout(self.interval)
return buffer
