diff options
| author | Gregory Nutt <gnutt@nuttx.org> | 2013-05-12 11:47:09 -0600 |
|---|---|---|
| committer | Gregory Nutt <gnutt@nuttx.org> | 2013-05-12 11:47:09 -0600 |
| commit | 761d051218d4bf29a71532d7e67a18beda63cb30 (patch) | |
| tree | cf7f509dda831dcc7257e379e4d241a01348f08e /NxWidgets/nxwm/include | |
| parent | 9cbcaf0b572ee505767e47fcc41cfe660c8e3ae3 (diff) | |
| download | nuttx-761d051218d4bf29a71532d7e67a18beda63cb30.tar.gz nuttx-761d051218d4bf29a71532d7e67a18beda63cb30.tar.bz2 nuttx-761d051218d4bf29a71532d7e67a18beda63cb30.zip | |
Fixe a race confition in NxWM::CCalibration
Diffstat (limited to 'NxWidgets/nxwm/include')
| -rw-r--r-- | NxWidgets/nxwm/include/ccalibration.hxx | 33 |
1 files changed, 28 insertions, 5 deletions
diff --git a/NxWidgets/nxwm/include/ccalibration.hxx b/NxWidgets/nxwm/include/ccalibration.hxx index a54a35bf7..f114a19a2 100644 --- a/NxWidgets/nxwm/include/ccalibration.hxx +++ b/NxWidgets/nxwm/include/ccalibration.hxx @@ -1,7 +1,7 @@ /**************************************************************************** * NxWidgets/nxwm/include/ccalibration.hxx * - * Copyright (C) 2012 Gregory Nutt. All rights reserved. + * Copyright (C) 2012-2013 Gregory Nutt. All rights reserved. * Author: Gregory Nutt <gnutt@nuttx.org> * * Redistribution and use in source and binary forms, with or without @@ -175,22 +175,45 @@ namespace NxWM /** * Return true if the calibration thread is running normally. There are - * lots of potential race conditions. Let's hope that things are running - * orderly and we that we do not have to concern ourself with them + * lots of potential race conditions. There are also two ambiguous + * states: + * + * 1) The thread may have been started but not yet running + * (CALTHREAD_STARTED), or the + * 2) The thread may been requested to terminate, but has not yet + * terminated (CALTHREAD_STOPREQUESTED) + * + * Both of those states will cause isRunning() to return false. * * @return True if the calibration thread is runnning normally. */ inline bool isRunning(void) const { - // What if the boundary states CALTHREAD_STARTED and CALTHREAD_STOPREQUESTED? - return (m_calthread == CALTHREAD_RUNNING || m_calthread == CALTHREAD_HIDE || m_calthread == CALTHREAD_SHOW); } /** + * Return true if the calibration thread is has been started and has not + * yet terminated. There is a potential race condition here when the + * thread has been requested to terminate, but has not yet terminated + * (CALTHREAD_STOPREQUESTED). isStarted() will return false in that case. + * + * @return True if the calibration thread has been started and/or is + * running normally. + */ + + inline bool isStarted(void) const + { + return (m_calthread == CALTHREAD_STARTED || + m_calthread == CALTHREAD_RUNNING || + m_calthread == CALTHREAD_HIDE || + m_calthread == CALTHREAD_SHOW); + } + + /** * The calibration thread. This is the entry point of a thread that provides the * calibration displays, waits for input, and collects calibration data. * |