#Call documentation

MuditaOS's call library is able to perform:

• ingoring and outgoing calls
• perform call filtering
  • on RING (notification that there is incoming call)
  • on CLIP (notification on identified call)
  • based on contacts
  • based on phone mode

The call logic is one of the oldest functionalities in the OS, which has been changed multiple times in the past. , therefore it has multiple visible (mis)conceptions. The current approach we want to keep is:

• Call handling logic should be in CellularCall.hpp - it's an interface for ServiceCellular used to perform calls
  • Especially all actions changing call - i.e. hanging, acting upon CLIP/RING, or setting up audio
  • It's responsible for multicast specific call states to parties interested (i.e. call answered)
• Call UI should be in application-call - and only UI, there should be no more state handling then required to show UI
  • all actions that changes call - shoud be passed to CellularCall

NOTE: Historically lots of state keeping was done in application call, while quite a bit of logic was glued in ServiceCellular - this is a wrong way to go.

#library organization

This library's goal is to encapsulate the whole call flow/flows we can have. It's end goal is to provide: actions and guards to write call state machine to asure full control over call processing.

Public API headers should be placed in include/call/ catalog - these are exported in CMake to include paths for related libraries All other headers should not be placed there. These are private internals of the library

#Call - how to write logic

CellularCall.hpp is written such as:

• CellularCall is state machine processor
• It has Call StateMachine inside and drives it
• API it requires is in api catalog
  • any API has to first define a virtual interface
  • then define platform implementation

State machine is written using boost::sml

NOTE API catalog should and can be further split into API header and platform implementation.

#Call state machine

Call state machine can be generated with:

ninja call_uml
call_uml > call.puml

Latest generated UML:

NOTE:* The UML is generated automatically, for better readability please change lambdas to functions