libbinder_rs: Add Strong<> and Weak<> Binder references (ddb3e6d7) · Commits · e / os / platform_frameworks_native

libs/binder/rust/src/binder.rs

+145 −13

Original line number	Diff line number	Diff line
		@@ -16,12 +16,17 @@

		//! Trait definitions for binder objects

		use crate::error::{status_t, Result};
		use crate::error::{status_t, Result, StatusCode};
		use crate::parcel::Parcel;
		use crate::proxy::{DeathRecipient, SpIBinder};
		use crate::proxy::{DeathRecipient, SpIBinder, WpIBinder};
		use crate::sys;

		use std::borrow::Borrow;
		use std::cmp::Ordering;
		use std::ffi::{c_void, CStr, CString};
		use std::fmt;
		use std::marker::PhantomData;
		use std::ops::Deref;
		use std::os::raw::c_char;
		use std::os::unix::io::AsRawFd;
		use std::ptr;
		@@ -44,7 +49,7 @@ pub type TransactionFlags = u32;
		/// interfaces) must implement this trait.
		///
		/// This is equivalent `IInterface` in C++.
		pub trait Interface {
		pub trait Interface: Send {
		/// Convert this binder object into a generic [`SpIBinder`] reference.
		fn as_binder(&self) -> SpIBinder {
		panic!("This object was not a Binder object and cannot be converted into an SpIBinder.")
		@@ -230,6 +235,132 @@ impl From<InterfaceClass> for *const sys::AIBinder_Class {
		}
		}

		/// Strong reference to a binder object
		pub struct Strong<I: FromIBinder + ?Sized>(Box<I>);

		impl<I: FromIBinder + ?Sized> Strong<I> {
		/// Create a new strong reference to the provided binder object
		pub fn new(binder: Box<I>) -> Self {
		Self(binder)
		}

		/// Construct a new weak reference to this binder
		pub fn downgrade(this: &Strong<I>) -> Weak<I> {
		Weak::new(this)
		}
		}

		impl<I: FromIBinder + ?Sized> Clone for Strong<I> {
		fn clone(&self) -> Self {
		// Since we hold a strong reference, we should always be able to create
		// a new strong reference to the same interface type, so try_from()
		// should never fail here.
		FromIBinder::try_from(self.0.as_binder()).unwrap()
		}
		}

		impl<I: FromIBinder + ?Sized> Borrow<I> for Strong<I> {
		fn borrow(&self) -> &I {
		&self.0
		}
		}

		impl<I: FromIBinder + ?Sized> AsRef<I> for Strong<I> {
		fn as_ref(&self) -> &I {
		&self.0
		}
		}

		impl<I: FromIBinder + ?Sized> Deref for Strong<I> {
		type Target = I;

		fn deref(&self) -> &Self::Target {
		&self.0
		}
		}

		impl<I: FromIBinder + fmt::Debug + ?Sized> fmt::Debug for Strong<I> {
		fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
		fmt::Debug::fmt(&**self, f)
		}
		}

		impl<I: FromIBinder + ?Sized> Ord for Strong<I> {
		fn cmp(&self, other: &Self) -> Ordering {
		self.0.as_binder().cmp(&other.0.as_binder())
		}
		}

		impl<I: FromIBinder + ?Sized> PartialOrd for Strong<I> {
		fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
		self.0.as_binder().partial_cmp(&other.0.as_binder())
		}
		}

		impl<I: FromIBinder + ?Sized> PartialEq for Strong<I> {
		fn eq(&self, other: &Self) -> bool {
		self.0.as_binder().eq(&other.0.as_binder())
		}
		}

		impl<I: FromIBinder + ?Sized> Eq for Strong<I> {}

		/// Weak reference to a binder object
		#[derive(Debug)]
		pub struct Weak<I: FromIBinder + ?Sized> {
		weak_binder: WpIBinder,
		interface_type: PhantomData<I>,
		}

		impl<I: FromIBinder + ?Sized> Weak<I> {
		/// Construct a new weak reference from a strong reference
		fn new(binder: &Strong<I>) -> Self {
		let weak_binder = binder.as_binder().downgrade();
		Weak {
		weak_binder,
		interface_type: PhantomData,
		}
		}

		/// Upgrade this weak reference to a strong reference if the binder object
		/// is still alive
		pub fn upgrade(&self) -> Result<Strong<I>> {
		self.weak_binder
		.promote()
		.ok_or(StatusCode::DEAD_OBJECT)
		.and_then(FromIBinder::try_from)
		}
		}

		impl<I: FromIBinder + ?Sized> Clone for Weak<I> {
		fn clone(&self) -> Self {
		Self {
		weak_binder: self.weak_binder.clone(),
		interface_type: PhantomData,
		}
		}
		}

		impl<I: FromIBinder + ?Sized> Ord for Weak<I> {
		fn cmp(&self, other: &Self) -> Ordering {
		self.weak_binder.cmp(&other.weak_binder)
		}
		}

		impl<I: FromIBinder + ?Sized> PartialOrd for Weak<I> {
		fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
		self.weak_binder.partial_cmp(&other.weak_binder)
		}
		}

		impl<I: FromIBinder + ?Sized> PartialEq for Weak<I> {
		fn eq(&self, other: &Self) -> bool {
		self.weak_binder == other.weak_binder
		}
		}

		impl<I: FromIBinder + ?Sized> Eq for Weak<I> {}

		/// Create a function implementing a static getter for an interface class.
		///
		/// Each binder interface (i.e. local [`Remotable`] service or remote proxy
		@@ -354,12 +485,12 @@ pub trait InterfaceClassMethods {
		/// }
		/// }
		/// ```
		pub trait FromIBinder {
		pub trait FromIBinder: Interface {
		/// Try to interpret a generic Binder object as this interface.
		///
		/// Returns a trait object for the `Self` interface if this object
		/// implements that interface.
		fn try_from(ibinder: SpIBinder) -> Result<Box<Self>>;
		fn try_from(ibinder: SpIBinder) -> Result<Strong<Self>>;
		}

		/// Trait for transparent Rust wrappers around android C++ native types.
		@@ -534,8 +665,9 @@ macro_rules! declare_binder_interface {

		impl $native {
		/// Create a new binder service.
		pub fn new_binder<T: $interface + Sync + Send + 'static>(inner: T) -> impl $interface {
		$crate::Binder::new($native(Box::new(inner)))
		pub fn new_binder<T: $interface + Sync + Send + 'static>(inner: T) -> $crate::Strong<dyn $interface> {
		let binder = $crate::Binder::new($native(Box::new(inner)));
		$crate::Strong::new(Box::new(binder))
		}
		}

		@@ -577,7 +709,7 @@ macro_rules! declare_binder_interface {
		}

		impl $crate::FromIBinder for dyn $interface {
		fn try_from(mut ibinder: $crate::SpIBinder) -> $crate::Result<Box<dyn $interface>> {
		fn try_from(mut ibinder: $crate::SpIBinder) -> $crate::Result<$crate::Strong<dyn $interface>> {
		use $crate::AssociateClass;

		let existing_class = ibinder.get_class();
		@@ -590,7 +722,7 @@ macro_rules! declare_binder_interface {
		// associated object as remote, because we can't cast it
		// into a Rust service object without a matching class
		// pointer.
		return Ok(Box::new(<$proxy as $crate::Proxy>::from_binder(ibinder)?));
		return Ok($crate::Strong::new(Box::new(<$proxy as $crate::Proxy>::from_binder(ibinder)?)));
		}
		}

		@@ -600,10 +732,10 @@ macro_rules! declare_binder_interface {
		if let Ok(service) = service {
		// We were able to associate with our expected class and
		// the service is local.
		return Ok(Box::new(service));
		return Ok($crate::Strong::new(Box::new(service)));
		} else {
		// Service is remote
		return Ok(Box::new(<$proxy as $crate::Proxy>::from_binder(ibinder)?));
		return Ok($crate::Strong::new(Box::new(<$proxy as $crate::Proxy>::from_binder(ibinder)?)));
		}
		}

		@@ -633,9 +765,9 @@ macro_rules! declare_binder_interface {
		}
		}

		// Convert a &dyn $interface to Box<dyn $interface>
		/// Convert a &dyn $interface to Strong<dyn $interface>
		impl std::borrow::ToOwned for dyn $interface {
		type Owned = Box<dyn $interface>;
		type Owned = $crate::Strong<dyn $interface>;
		fn to_owned(&self) -> Self::Owned {
		self.as_binder().into_interface()
		.expect(concat!("Error cloning interface ", stringify!($interface)))

libs/binder/rust/src/lib.rs

+4 −2

Original line number	Diff line number	Diff line
		@@ -107,7 +107,8 @@ use binder_ndk_sys as sys;
		pub mod parcel;

		pub use crate::binder::{
		FromIBinder, IBinder, Interface, InterfaceClass, Remotable, TransactionCode, TransactionFlags,
		FromIBinder, IBinder, Interface, InterfaceClass, Remotable, Strong, TransactionCode,
		TransactionFlags, Weak,
		};
		pub use error::{status_t, ExceptionCode, Result, Status, StatusCode};
		pub use native::add_service;
		@@ -122,7 +123,8 @@ pub mod public_api {
		pub use super::parcel::ParcelFileDescriptor;
		pub use super::{add_service, get_interface};
		pub use super::{
		ExceptionCode, Interface, ProcessState, SpIBinder, Status, StatusCode, WpIBinder,
		ExceptionCode, Interface, ProcessState, SpIBinder, Status, StatusCode, Strong, ThreadState,
		Weak, WpIBinder,
		};

		/// Binder result containing a [`Status`] on error.

libs/binder/rust/src/parcel/parcelable.rs

+5 −5

Original line number	Diff line number	Diff line
		@@ -14,7 +14,7 @@
		* limitations under the License.
		*/

		use crate::binder::{AsNative, FromIBinder};
		use crate::binder::{AsNative, FromIBinder, Strong};
		use crate::error::{status_result, status_t, Result, Status, StatusCode};
		use crate::parcel::Parcel;
		use crate::proxy::SpIBinder;
		@@ -628,26 +628,26 @@ impl Deserialize for Status {
		}
		}

		impl<T: Serialize + ?Sized> Serialize for Box<T> {
		impl<T: Serialize + FromIBinder + ?Sized> Serialize for Strong<T> {
		fn serialize(&self, parcel: &mut Parcel) -> Result<()> {
		Serialize::serialize(&**self, parcel)
		}
		}

		impl<T: SerializeOption + ?Sized> SerializeOption for Box<T> {
		impl<T: SerializeOption + FromIBinder + ?Sized> SerializeOption for Strong<T> {
		fn serialize_option(this: Option<&Self>, parcel: &mut Parcel) -> Result<()> {
		SerializeOption::serialize_option(this.map(\|b\| &**b), parcel)
		}
		}

		impl<T: FromIBinder + ?Sized> Deserialize for Box<T> {
		impl<T: FromIBinder + ?Sized> Deserialize for Strong<T> {
		fn deserialize(parcel: &Parcel) -> Result<Self> {
		let ibinder: SpIBinder = parcel.read()?;
		FromIBinder::try_from(ibinder)
		}
		}

		impl<T: FromIBinder + ?Sized> DeserializeOption for Box<T> {
		impl<T: FromIBinder + ?Sized> DeserializeOption for Strong<T> {
		fn deserialize_option(parcel: &Parcel) -> Result<Option<Self>> {
		let ibinder: Option<SpIBinder> = parcel.read()?;
		ibinder.map(FromIBinder::try_from).transpose()

libs/binder/rust/src/proxy.rs

+92 −5

Original line number	Diff line number	Diff line
		@@ -17,7 +17,7 @@
		//! Rust API for interacting with a remote binder service.

		use crate::binder::{
		AsNative, FromIBinder, IBinder, Interface, InterfaceClass, TransactionCode, TransactionFlags,
		AsNative, FromIBinder, IBinder, Interface, InterfaceClass, Strong, TransactionCode, TransactionFlags,
		};
		use crate::error::{status_result, Result, StatusCode};
		use crate::parcel::{
		@@ -27,6 +27,7 @@ use crate::parcel::{
		use crate::sys;

		use std::convert::TryInto;
		use std::cmp::Ordering;
		use std::ffi::{c_void, CString};
		use std::fmt;
		use std::os::unix::io::AsRawFd;
		@@ -99,7 +100,7 @@ impl SpIBinder {
		///
		/// If this object does not implement the expected interface, the error
		/// `StatusCode::BAD_TYPE` is returned.
		pub fn into_interface<I: FromIBinder + ?Sized>(self) -> Result<Box<I>> {
		pub fn into_interface<I: FromIBinder + Interface + ?Sized>(self) -> Result<Strong<I>> {
		FromIBinder::try_from(self)
		}

		@@ -148,6 +149,36 @@ impl AssociateClass for SpIBinder {
		}
		}

		impl Ord for SpIBinder {
		fn cmp(&self, other: &Self) -> Ordering {
		let less_than = unsafe {
		// Safety: SpIBinder always holds a valid `AIBinder` pointer, so
		// this pointer is always safe to pass to `AIBinder_lt` (null is
		// also safe to pass to this function, but we should never do that).
		sys::AIBinder_lt(self.0, other.0)
		};
		let greater_than = unsafe {
		// Safety: SpIBinder always holds a valid `AIBinder` pointer, so
		// this pointer is always safe to pass to `AIBinder_lt` (null is
		// also safe to pass to this function, but we should never do that).
		sys::AIBinder_lt(other.0, self.0)
		};
		if !less_than && !greater_than {
		Ordering::Equal
		} else if less_than {
		Ordering::Less
		} else {
		Ordering::Greater
		}
		}
		}

		impl PartialOrd for SpIBinder {
		fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
		Some(self.cmp(other))
		}
		}

		impl PartialEq for SpIBinder {
		fn eq(&self, other: &Self) -> bool {
		ptr::eq(self.0, other.0)
		@@ -326,7 +357,7 @@ impl<T: AsNative<sys::AIBinder>> IBinder for T {
		// Safety: `SpIBinder` guarantees that `self` always contains a
		// valid pointer to an `AIBinder`. `recipient` can always be
		// converted into a valid pointer to an
		// `AIBinder_DeatRecipient`. Any value is safe to pass as the
		// `AIBinder_DeathRecipient`. Any value is safe to pass as the
		// cookie, although we depend on this value being set by
		// `get_cookie` when the death recipient callback is called.
		sys::AIBinder_linkToDeath(
		@@ -342,7 +373,7 @@ impl<T: AsNative<sys::AIBinder>> IBinder for T {
		// Safety: `SpIBinder` guarantees that `self` always contains a
		// valid pointer to an `AIBinder`. `recipient` can always be
		// converted into a valid pointer to an
		// `AIBinder_DeatRecipient`. Any value is safe to pass as the
		// `AIBinder_DeathRecipient`. Any value is safe to pass as the
		// cookie, although we depend on this value being set by
		// `get_cookie` when the death recipient callback is called.
		sys::AIBinder_unlinkToDeath(
		@@ -430,6 +461,62 @@ impl WpIBinder {
		}
		}

		impl Clone for WpIBinder {
		fn clone(&self) -> Self {
		let ptr = unsafe {
		// Safety: WpIBinder always holds a valid `AIBinder_Weak` pointer,
		// so this pointer is always safe to pass to `AIBinder_Weak_clone`
		// (although null is also a safe value to pass to this API).
		//
		// We get ownership of the returned pointer, so can construct a new
		// WpIBinder object from it.
		sys::AIBinder_Weak_clone(self.0)
		};
		assert!(!ptr.is_null(), "Unexpected null pointer from AIBinder_Weak_clone");
		Self(ptr)
		}
		}

		impl Ord for WpIBinder {
		fn cmp(&self, other: &Self) -> Ordering {
		let less_than = unsafe {
		// Safety: WpIBinder always holds a valid `AIBinder_Weak` pointer,
		// so this pointer is always safe to pass to `AIBinder_Weak_lt`
		// (null is also safe to pass to this function, but we should never
		// do that).
		sys::AIBinder_Weak_lt(self.0, other.0)
		};
		let greater_than = unsafe {
		// Safety: WpIBinder always holds a valid `AIBinder_Weak` pointer,
		// so this pointer is always safe to pass to `AIBinder_Weak_lt`
		// (null is also safe to pass to this function, but we should never
		// do that).
		sys::AIBinder_Weak_lt(other.0, self.0)
		};
		if !less_than && !greater_than {
		Ordering::Equal
		} else if less_than {
		Ordering::Less
		} else {
		Ordering::Greater
		}
		}
		}

		impl PartialOrd for WpIBinder {
		fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
		Some(self.cmp(other))
		}
		}

		impl PartialEq for WpIBinder {
		fn eq(&self, other: &Self) -> bool {
		self.cmp(other) == Ordering::Equal
		}
		}

		impl Eq for WpIBinder {}

		impl Drop for WpIBinder {
		fn drop(&mut self) {
		unsafe {
		@@ -564,7 +651,7 @@ pub fn get_service(name: &str) -> Option<SpIBinder> {

		/// 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<Box<T>> {
		pub fn get_interface<T: FromIBinder + ?Sized>(name: &str) -> Result<Strong<T>> {
		let service = get_service(name);
		match service {
		Some(service) => FromIBinder::try_from(service),

libs/binder/rust/tests/integration.rs

+57 −6

Original line number	Diff line number	Diff line
		@@ -209,7 +209,7 @@ mod tests {
		use std::thread;
		use std::time::Duration;

		use binder::{Binder, DeathRecipient, FromIBinder, IBinder, Interface, SpIBinder, StatusCode};
		use binder::{Binder, DeathRecipient, FromIBinder, IBinder, Interface, SpIBinder, StatusCode, Strong};

		use super::{BnTest, ITest, ITestSameDescriptor, RUST_SERVICE_BINARY, TestService};

		@@ -271,7 +271,7 @@ mod tests {
		fn trivial_client() {
		let service_name = "trivial_client_test";
		let _process = ScopedServiceProcess::new(service_name);
		let test_client: Box<dyn ITest> =
		let test_client: Strong<dyn ITest> =
		binder::get_interface(service_name).expect("Did not get manager binder service");
		assert_eq!(test_client.test().unwrap(), "trivial_client_test");
		}
		@@ -280,7 +280,7 @@ mod tests {
		fn get_selinux_context() {
		let service_name = "get_selinux_context";
		let _process = ScopedServiceProcess::new(service_name);
		let test_client: Box<dyn ITest> =
		let test_client: Strong<dyn ITest> =
		binder::get_interface(service_name).expect("Did not get manager binder service");
		let expected_context = unsafe {
		let mut out_ptr = ptr::null_mut();
		@@ -453,7 +453,7 @@ mod tests {

		let extension = maybe_extension.expect("Remote binder did not have an extension");

		let extension: Box<dyn ITest> = FromIBinder::try_from(extension)
		let extension: Strong<dyn ITest> = FromIBinder::try_from(extension)
		.expect("Extension could not be converted to the expected interface");

		assert_eq!(extension.test().unwrap(), extension_name);
		@@ -479,7 +479,7 @@ mod tests {

		// This should succeed although we will have to treat the service as
		// remote.
		let _interface: Box<dyn ITestSameDescriptor> = FromIBinder::try_from(service.as_binder())
		let _interface: Strong<dyn ITestSameDescriptor> = FromIBinder::try_from(service.as_binder())
		.expect("Could not re-interpret service as the ITestSameDescriptor interface");
		}

		@@ -490,9 +490,60 @@ mod tests {
		let service_ibinder = BnTest::new_binder(TestService { s: service_name.to_string() })
		.as_binder();

		let service: Box<dyn ITest> = service_ibinder.into_interface()
		let service: Strong<dyn ITest> = service_ibinder.into_interface()
		.expect("Could not reassociate the generic ibinder");

		assert_eq!(service.test().unwrap(), service_name);
		}

		#[test]
		fn weak_binder_upgrade() {
		let service_name = "testing_service";
		let service = BnTest::new_binder(TestService { s: service_name.to_string() });

		let weak = Strong::downgrade(&service);

		let upgraded = weak.upgrade().expect("Could not upgrade weak binder");

		assert_eq!(service, upgraded);
		}

		#[test]
		fn weak_binder_upgrade_dead() {
		let service_name = "testing_service";
		let weak = {
		let service = BnTest::new_binder(TestService { s: service_name.to_string() });

		Strong::downgrade(&service)
		};

		assert_eq!(weak.upgrade(), Err(StatusCode::DEAD_OBJECT));
		}

		#[test]
		fn weak_binder_clone() {
		let service_name = "testing_service";
		let service = BnTest::new_binder(TestService { s: service_name.to_string() });

		let weak = Strong::downgrade(&service);
		let cloned = weak.clone();
		assert_eq!(weak, cloned);

		let upgraded = weak.upgrade().expect("Could not upgrade weak binder");
		let clone_upgraded = cloned.upgrade().expect("Could not upgrade weak binder");

		assert_eq!(service, upgraded);
		assert_eq!(service, clone_upgraded);
		}

		#[test]
		#[allow(clippy::eq_op)]
		fn binder_ord() {
		let service1 = BnTest::new_binder(TestService { s: "testing_service1".to_string() });
		let service2 = BnTest::new_binder(TestService { s: "testing_service2".to_string() });

		assert!(!(service1 < service1));
		assert!(!(service1 > service1));
		assert_eq!(service1 < service2, !(service2 < service1));
		}
		}