This indicates whether or not the Sendable listeners are installed.
It is set to true when SendableBuilder.startListeners() starts the listeners,
and set to false when SendableBuilder.stopListeners() stops the listeners.
This allows dashboards to choose to change their widget display based on
whether or not the value is actually controllable.
Also switch eventName and gameSpecificData to fixed 64-byte arrays to avoid mallocs and
extra NetComm calls. This behavior matches 2018 LabView.
The DS caching is kept in Java to avoid JNI and/or massive amounts of allocations.
This does not increase latency because Java still only hits NetComm once.
Moving the DS caching benefits all languages other than Java, because it avoids the need
for individual implementations. If caching is ever added to NetComm, it will then only be
necessary to remove it from the HAL and Java rather than all languages.
It is much more reliable than the old approach, as it no longer depends on a magic string
in a manifest file, and if the user changes their main class, or makes it not import from
something RobotBase, it will fail to compile instead of failing at runtime.
With requiring an importer, we should be able to automate this in the importer.
I don't have a good way to ensure this always works, so this is going to be a documentation issue.
But initializeHardwareConfiguration is now reentrant, so we can just have all tests call it.
This fixes DriverStation in WPILibJ to check the existence of buttons and hold the data mutex in getStickButtonPressed() and getStickButtonReleased(), as the corresponding methods in WPILibC do.
It was using array indexing to map the return value of
DriverStation.getJoystickType() to HIDType when the enum should instead be
constructed from the int value. C++ already does this.
Fixes#968.
SendableChooser::InitSendable() is written such that it saves the table
being used in an instance variable. This doesn't work if the chooser is
added to both LiveWindow and SmartDashboard. Normally it is not added to
LiveWindow because the name is empty, but if setName() is called this could
still happen. Note adding the same SendableChooser to SmartDashboard with
two different names is also not currently supported, for the same reason.
The correct solution will be to remove the instance variable, but this is
too high risk to implement mid-season, so instead just remove from LiveWindow.
Reset() is the only function without a null check around it. We call the function on startup, which means if it is unplugged the robot crashes.
Also added an accessor for checking if it is connected, as some teams (us) would like to handle the case where it was not connected on startup.
