Race condition in activity dependent discovery management

[michaelroland]

If the SDK detects an activity transition to STILL (device not moving) it starts a disable delay timeout (10 minutes) before it actually disables discovery (stopDetectionDelayed()). If the device then transitions to another state (e.g. walking), it issues an immediate startDetection() command. If that happens before the 10 minute timeout is over, the delay timeout (handled by a seperate thread) will still continue to run and will disable discovery once expired, even if the user still walking around.

Example 1 (no problem)

• Device is WALKING.
• Device transitions to STILL: stopDetectionDelayed() is called and timeout starts counting down
• Device continues to be STILL for 10 minutes: CountdownThreadHandler invokes stopDetection() and discovery/broadcasting stops
• Device transitions to WALKING: startDetection() is called, the discovery starts and will continue to run (no problem)

Example 2 (malfunction)

• Device is WALKING.
• Device transitions to STILL: stopDetectionDelayed() is called and timeout starts counting down
• After 9 minutes, device transitions to WALKING: startDetection() is called and the discovery starts
• One minute later: CountdownThreadHandler invokes stopDetection() and discovery/broadcasting stops (eventhough device is still WALKING)