Add wait_for_interface and wait_for_service.

Bug: 183582651
Test: atest rustBinderTest rustBinderTestService
Test: atest VirtualizationTestCases
Change-Id: I7e25b61ac6717338642ff4d5588e6d34c656382d
diff --git a/libs/binder/rust/src/lib.rs b/libs/binder/rust/src/lib.rs
index 2694cba..7c0584b 100644
--- a/libs/binder/rust/src/lib.rs
+++ b/libs/binder/rust/src/lib.rs
@@ -115,14 +115,14 @@
 pub use native::add_service;
 pub use native::Binder;
 pub use parcel::Parcel;
-pub use proxy::{get_interface, get_service};
+pub use proxy::{get_interface, get_service, wait_for_interface, wait_for_service};
 pub use proxy::{AssociateClass, DeathRecipient, Proxy, SpIBinder, WpIBinder};
 pub use state::{ProcessState, ThreadState};
 
 /// The public API usable outside AIDL-generated interface crates.
 pub mod public_api {
     pub use super::parcel::ParcelFileDescriptor;
-    pub use super::{add_service, get_interface};
+    pub use super::{add_service, get_interface, wait_for_interface};
     pub use super::{
         BinderFeatures, DeathRecipient, ExceptionCode, IBinder, Interface, ProcessState, SpIBinder,
         Status, StatusCode, Strong, ThreadState, Weak, WpIBinder,
diff --git a/libs/binder/rust/src/proxy.rs b/libs/binder/rust/src/proxy.rs
index 52036f5..4a6d118 100644
--- a/libs/binder/rust/src/proxy.rs
+++ b/libs/binder/rust/src/proxy.rs
@@ -653,6 +653,18 @@
     }
 }
 
+/// Retrieve an existing service, or start it if it is configured as a dynamic
+/// service and isn't yet started.
+pub fn wait_for_service(name: &str) -> Option<SpIBinder> {
+    let name = CString::new(name).ok()?;
+    unsafe {
+        // Safety: `AServiceManager_waitforService` returns either a null
+        // pointer or a valid pointer to an owned `AIBinder`. Either of these
+        // values is safe to pass to `SpIBinder::from_raw`.
+        SpIBinder::from_raw(sys::AServiceManager_waitForService(name.as_ptr()))
+    }
+}
+
 /// Retrieve an existing service for a particular interface, blocking for a few
 /// seconds if it doesn't yet exist.
 pub fn get_interface<T: FromIBinder + ?Sized>(name: &str) -> Result<Strong<T>> {
@@ -663,6 +675,16 @@
     }
 }
 
+/// Retrieve an existing service for a particular interface, or start it if it
+/// is configured as a dynamic service and isn't yet started.
+pub fn wait_for_interface<T: FromIBinder + ?Sized>(name: &str) -> Result<Strong<T>> {
+    let service = wait_for_service(name);
+    match service {
+        Some(service) => FromIBinder::try_from(service),
+        None => Err(StatusCode::NAME_NOT_FOUND),
+    }
+}
+
 /// # Safety
 ///
 /// `SpIBinder` guarantees that `binder` always contains a valid pointer to an