| Daniel Erat | 3e3f7f4 | 2010-03-29 17:19:14 -0700 | [diff] [blame^] | 1 | # Copyright (c) 2010 The Chromium OS Authors. All rights reserved. |
| 2 | # Use of this source code is governed by a BSD-style license that can be |
| 3 | # found in the LICENSE file. |
| 4 | |
| 5 | import time |
| 6 | from autotest_lib.client.common_lib import error |
| 7 | |
| 8 | |
| 9 | def poll_for_condition( |
| 10 | condition, exception=None, timeout=10, sleep_interval=0.1): |
| 11 | """Poll until a condition becomes true. |
| 12 | |
| 13 | condition: function taking no args and returning bool |
| 14 | exception: exception to throw if condition doesn't become true |
| 15 | timeout: maximum number of seconds to wait |
| 16 | sleep_interval: time to sleep between polls |
| 17 | |
| 18 | Raises: |
| 19 | 'exception' arg if supplied; error.TestError otherwise |
| 20 | """ |
| 21 | start_time = time.time() |
| 22 | while True: |
| 23 | if condition(): |
| 24 | return |
| 25 | if time.time() + sleep_interval - start_time > timeout: |
| 26 | raise exception if exception else error.TestError( |
| 27 | 'Timed out waiting for condition') |
| 28 | time.sleep(sleep_interval) |