Service Implementation
We can now implement the AIDL service:
birthday_service/src/lib.rs:
//! Implementation of the `IBirthdayService` AIDL interface.
use com_example_birthdayservice::aidl::com::example::birthdayservice::IBirthdayService::IBirthdayService;
use com_example_birthdayservice::binder;
/// The `IBirthdayService` implementation.
pub struct BirthdayService;
impl binder::Interface for BirthdayService {}
impl IBirthdayService for BirthdayService {
fn wishHappyBirthday(&self, name: &str, years: i32) -> binder::Result<String> {
Ok(format!("Happy Birthday {name}, congratulations with the {years} years!"))
}
}
birthday_service/Android.bp:
rust_library {
name: "libbirthdayservice",
srcs: ["src/lib.rs"],
crate_name: "birthdayservice",
rustlibs: [
"com.example.birthdayservice-rust",
"libbinder_rs",
],
}
Speaker Notes
- 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.
- 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
- TODO: What does the
binder::Interface
trait do? Are there methods to override? Where source?