Validate that we don't exceed handles number of allocated handles for a service

[nkolban]

When we create a BLE Service, we must define the maximum number of handles associated with the service. The default is 15. As we add characteristics to the service and then descriptors to the characteristics (of that service), we start to consume the available handles. Since we KNOW how many handles we have allocated to the service and we know how many characteristics and descriptors we have previously added, we should be able to "trap" adding too many characteristics and descriptors to any given service and alert the programmer to increase the number of handles they should allocate.

[BobaTrek]

I have run into the max number of handles limit as well, and have been unable to increase it by passing in numHandles to BLEServer::createService( BLEUUID, int numHandles ) call.

//mpBLEService = mpBLEServer->createService( BLEUUID("91bad492-b950-4226-aa2b-4ede9fa42f59"), 30 );  // nRF Connect Fails to see Services

Increasing numHandles this way led to the following behavior:
In nRF Connect, my BLEDevice still shows up, but the BLEService and all of it's BLECharacteristics no longer show up.

I then tried increasing the default numHandles in BLEServer.h from 15 to 30, and BLEService.h from 10 to 30, so that I could continue to call the createService passing just a BLEUUID:

//mpBLEService = mpBLEServer->createService( BLEUUID("91bad492-b950-4226-aa2b-4ede9fa42f59") );  // nRF Connect sees Services and Characteristics

Increasing numHandles this way led to the following behavior:
In nRF Connect, my BLEDevice still shows up, and the BLEService and all of it's BLECharacteristics still show up.

Side note about the default numHandles:

In the code the max number of BLEService handles is 10 in one place, and 15 in another.

In BLEServer we have a default of 15:
BLEService* createService(BLEUUID uuid, uint32_t numHandles=15);
https://github.com/nkolban/esp32-snippets/blob/master/cpp_utils/BLEServer.h#L56

In BLEService we have a default of 10:
BLEService(const char* uuid, uint32_t numHandles=10);
BLEService(BLEUUID uuid, uint32_t numHandles=10);
https://github.com/nkolban/esp32-snippets/blob/master/cpp_utils/BLEService.h#L55

[chegewara]

If you are working with esp-idf environment then you can read this to fix issue with creating service:

//mpBLEService = mpBLEServer->createService( "91bad492-b950-4226-aa2b-4ede9fa42f59" );  // Sees Services, but I need more handles
//mpBLEService = mpBLEServer->createService( BLEUUID("91bad492-b950-4226-aa2b-4ede9fa42f59") );  // Fails to see Services
//mpBLEService = mpBLEServer->createService( BLEUUID("91bad492-b950-4226-aa2b-4ede9fa42f59"), 10 );  // Fails to see Services
//mpBLEService = mpBLEServer->createService( BLEUUID("91bad492-b950-4226-aa2b-4ede9fa42f59"), 15 );  // Fails to see Services

#264 (comment)

[BobaTrek]

Yup - same problem - Thanks!

For now changing the default numHandles in BLEService.h from 10 to 30, and in BLEServer.h from 15 to 30 allows me to bypass the BLEUUID issue.

Since the default numHandles is in two places, I would like to suggest using a #define instead.

Thanks for your incredibly quick response!

[chegewara]

As i mentioned, if you are working with esp-idf you can change settings in menuconfig and create service with handle number:
mpBLEService = mpBLEServer->createService( BLEUUID("91bad492-b950-4226-aa2b-4ede9fa42f59"), 15 );

[nkolban]

Changed the logic to make BLEService a private constructor ... this means that we can't perform a new BLEService() outside of the BLE classes themselves. This makes sense since the only way we should create a service is by asking the server to do it for us. I also removed the default number of handles from the BLEService constructor ... so now there is nothing to get out of sync.