Service Implementation

We can now implement the AIDL service:

birthday_service/src/lib.rs:

# // Copyright 2024 Google LLC
# // SPDX-License-Identifier: Apache-2.0
#
//! Implementation of the `IBirthdayService` AIDL interface.
use com_example_birthdayservice::aidl::com::example::birthdayservice::IBirthdayService::IBirthdayService;
use com_example_birthdayservice::binder;

{{#include ../birthday_service/src/lib.rs:IBirthdayService}}
}

birthday_service/Android.bp:

{{#include ../birthday_service/Android.bp:libbirthdayservice}}

• Point out the path to the generated IBirthdayService trait, and explain why each of the segments is necessary.
• Note that wishHappyBirthday and other AIDL IPC methods take &self (instead of &mut self).
  • This is necessary because Binder responds to incoming requests on a thread pool, allowing for multiple requests to be processed in parallel. This requires that the service methods only get a shared reference to self.
  • Any state that needs to be modified by the service will have to be put in something like a Mutex to allow for safe mutation.
  • The correct approach for managing service state depends heavily on the details of your service.
• TODO: What does the binder::Interface trait do? Are there methods to override? Where is the source?