Module interoptopus::patterns::service

Bundles function with common receiver into a class or service in object oriented languages.

Services are defined via the pattern_service_manual macro and consists of the following items:

• an opaque receiver type,
• a constructor function of signature fn(mmR, ...) -> E
• destructor function of signature unsafe fn(mmR) -> E
• arbitrary many methods of signature fn(mR, ...) -> ?

where

• mmR refers to a &mut *mut Receiver, *mut *mut Receiver or Option<&mut *mut Receiver>,
• mR refers to a &mut Receiver, *mut Receiver or Option<&mut Receiver>,
• E to a success enum,
• ... ane ? to arbitrary types.

The constructor:

• must return E::SUCCESS if and only if it successfully wrote an instance of Receiver into mmR
• may only write a valid instance or leave the parameter at null

The unsafe destructor:

• must handle any values produced by a constructor that successfully returned,
• if it successfully completes, it must write a null pointer into mmR,

Violation of any of these conditions may cause UB in FFI calls as the generated bindings rely on this contract. In addition the bindings will guarantee (and the destructor’s signature should indicate) that it

• will only invoked if the constructor returned E::SUCCESS,
• the value for mmR will be exactly the value returned by a previous constructor invocation,

Structs

Service

Combines a receiver, constructor, destructor and multiple methods in one entity.

Traits

FailureDefault

For types that can be returned by a generated service what to return when things went wrong?