binder_rs: add OwnedParcel (268458c0) · Commits · e / os / android_frameworks_native-old

libs/binder/rust/src/binder.rs

+8 −8

Original line number	Diff line number	Diff line
		@@ -17,7 +17,7 @@
		//! Trait definitions for binder objects

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

		@@ -177,25 +177,25 @@ pub trait IBinderInternal: IBinder {
		fn get_extension(&mut self) -> Result<Option<SpIBinder>>;

		/// Create a Parcel that can be used with `submit_transact`.
		fn prepare_transact(&self) -> Result<Parcel>;
		fn prepare_transact(&self) -> Result<OwnedParcel>;

		/// Perform a generic operation with the object.
		///
		/// The provided [`Parcel`] must have been created by a call to
		/// The provided [`OwnedParcel`] must have been created by a call to
		/// `prepare_transact` on the same binder.
		///
		/// # Arguments
		///
		/// * `code` - Transaction code for the operation.
		/// * `data` - [`Parcel`] with input data.
		/// * `data` - [`OwnedParcel`] with input data.
		/// * `flags` - Transaction flags, e.g. marking the transaction as
		/// asynchronous ([`FLAG_ONEWAY`](FLAG_ONEWAY)).
		fn submit_transact(
		&self,
		code: TransactionCode,
		data: Parcel,
		data: OwnedParcel,
		flags: TransactionFlags,
		) -> Result<Parcel>;
		) -> Result<OwnedParcel>;

		/// Perform a generic operation with the object. This is a convenience
		/// method that internally calls `prepare_transact` followed by
		@@ -213,8 +213,8 @@ pub trait IBinderInternal: IBinder {
		input_callback: F,
		) -> Result<Parcel> {
		let mut parcel = self.prepare_transact()?;
		input_callback(&mut parcel)?;
		self.submit_transact(code, parcel, flags)
		input_callback(&mut parcel.borrowed())?;
		self.submit_transact(code, parcel, flags).map(OwnedParcel::into_parcel)
		}
		}

libs/binder/rust/src/lib.rs

+1 −1

Original line number	Diff line number	Diff line
		@@ -113,7 +113,7 @@ pub use crate::binder::{
		};
		pub use error::{status_t, ExceptionCode, Result, Status, StatusCode};
		pub use native::{add_service, force_lazy_services_persist, register_lazy_service, Binder};
		pub use parcel::Parcel;
		pub use parcel::{OwnedParcel, Parcel};
		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};

libs/binder/rust/src/parcel.rs

+120 −27

Original line number	Diff line number	Diff line
		@@ -23,6 +23,7 @@ use crate::sys;

		use std::cell::RefCell;
		use std::convert::TryInto;
		use std::marker::PhantomData;
		use std::mem::ManuallyDrop;
		use std::ptr;
		use std::fmt;
		@@ -52,6 +53,106 @@ pub enum Parcel {
		Borrowed(*mut sys::AParcel),
		}

		/// A variant of Parcel that is known to be owned.
		pub struct OwnedParcel {
		ptr: *mut sys::AParcel,
		}

		/// # Safety
		///
		/// This type guarantees that it owns the AParcel and that all access to
		/// the AParcel happens through the OwnedParcel, so it is ok to send across
		/// threads.
		unsafe impl Send for OwnedParcel {}

		/// A variant of Parcel that is known to be borrowed.
		pub struct BorrowedParcel<'a> {
		inner: Parcel,
		_lifetime: PhantomData<&'a mut Parcel>,
		}

		impl OwnedParcel {
		/// Create a new empty `OwnedParcel`.
		pub fn new() -> OwnedParcel {
		let ptr = unsafe {
		// Safety: If `AParcel_create` succeeds, it always returns
		// a valid pointer. If it fails, the process will crash.
		sys::AParcel_create()
		};
		assert!(!ptr.is_null());
		Self { ptr }
		}

		/// Create an owned reference to a parcel object from a raw pointer.
		///
		/// # Safety
		///
		/// This constructor is safe if the raw pointer parameter is either null
		/// (resulting in `None`), or a valid pointer to an `AParcel` object. The
		/// parcel object must be owned by the caller prior to this call, as this
		/// constructor takes ownership of the parcel and will destroy it on drop.
		///
		/// Additionally, the caller must guarantee that it is valid to take
		/// ownership of the AParcel object. All future access to the AParcel
		/// must happen through this `OwnedParcel`.
		///
		/// Because `OwnedParcel` implements `Send`, the pointer must never point
		/// to any thread-local data, e.g., a variable on the stack, either directly
		/// or indirectly.
		pub unsafe fn from_raw(ptr: *mut sys::AParcel) -> Option<OwnedParcel> {
		ptr.as_mut().map(\|ptr\| Self { ptr })
		}

		/// Consume the parcel, transferring ownership to the caller.
		pub(crate) fn into_raw(self) -> *mut sys::AParcel {
		let ptr = self.ptr;
		let _ = ManuallyDrop::new(self);
		ptr
		}

		/// Convert this `OwnedParcel` into an owned `Parcel`.
		pub fn into_parcel(self) -> Parcel {
		Parcel::Owned(self.into_raw())
		}

		/// Get a borrowed view into the contents of this `Parcel`.
		pub fn borrowed(&mut self) -> BorrowedParcel<'_> {
		BorrowedParcel {
		inner: Parcel::Borrowed(self.ptr),
		_lifetime: PhantomData,
		}
		}
		}

		impl Default for OwnedParcel {
		fn default() -> Self {
		Self::new()
		}
		}

		impl Clone for OwnedParcel {
		fn clone(&self) -> Self {
		let mut new_parcel = Self::new();
		new_parcel
		.borrowed()
		.append_all_from(&Parcel::Borrowed(self.ptr))
		.expect("Failed to append from Parcel");
		new_parcel
		}
		}

		impl<'a> std::ops::Deref for BorrowedParcel<'a> {
		type Target = Parcel;
		fn deref(&self) -> &Parcel {
		&self.inner
		}
		}
		impl<'a> std::ops::DerefMut for BorrowedParcel<'a> {
		fn deref_mut(&mut self) -> &mut Parcel {
		&mut self.inner
		}
		}

		/// # Safety
		///
		/// The `Parcel` constructors guarantee that a `Parcel` object will always
		@@ -95,33 +196,6 @@ impl Parcel {
		pub(crate) unsafe fn borrowed(ptr: *mut sys::AParcel) -> Option<Parcel> {
		ptr.as_mut().map(\|ptr\| Self::Borrowed(ptr))
		}

		/// Create an owned reference to a parcel object from a raw pointer.
		///
		/// # Safety
		///
		/// This constructor is safe if the raw pointer parameter is either null
		/// (resulting in `None`), or a valid pointer to an `AParcel` object. The
		/// parcel object must be owned by the caller prior to this call, as this
		/// constructor takes ownership of the parcel and will destroy it on drop.
		pub(crate) unsafe fn owned(ptr: *mut sys::AParcel) -> Option<Parcel> {
		ptr.as_mut().map(\|ptr\| Self::Owned(ptr))
		}

		/// Consume the parcel, transferring ownership to the caller if the parcel
		/// was owned.
		pub(crate) fn into_raw(mut self) -> *mut sys::AParcel {
		let ptr = self.as_native_mut();
		let _ = ManuallyDrop::new(self);
		ptr
		}

		pub(crate) fn is_owned(&self) -> bool {
		match *self {
		Self::Owned(_) => true,
		Self::Borrowed(_) => false,
		}
		}
		}

		impl Default for Parcel {
		@@ -478,6 +552,18 @@ impl Drop for Parcel {
		}
		}

		impl Drop for OwnedParcel {
		fn drop(&mut self) {
		// Run the C++ Parcel complete object destructor
		unsafe {
		// Safety: `OwnedParcel` always contains a valid pointer to an
		// `AParcel`. Since we own the parcel, we can safely delete it
		// here.
		sys::AParcel_delete(self.ptr)
		}
		}
		}

		impl fmt::Debug for Parcel {
		fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		f.debug_struct("Parcel")
		@@ -485,6 +571,13 @@ impl fmt::Debug for Parcel {
		}
		}

		impl fmt::Debug for OwnedParcel {
		fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		f.debug_struct("OwnedParcel")
		.finish()
		}
		}

		#[test]
		fn test_read_write() {
		let mut parcel = Parcel::new();

libs/binder/rust/src/proxy.rs

+8 −10

Original line number	Diff line number	Diff line
		@@ -22,7 +22,7 @@ use crate::binder::{
		};
		use crate::error::{status_result, Result, StatusCode};
		use crate::parcel::{
		Deserialize, DeserializeArray, DeserializeOption, Parcel, Serialize, SerializeArray,
		Deserialize, DeserializeArray, DeserializeOption, OwnedParcel, Parcel, Serialize, SerializeArray,
		SerializeOption,
		};
		use crate::sys;
		@@ -235,7 +235,7 @@ impl Drop for SpIBinder {
		}

		impl<T: AsNative<sys::AIBinder>> IBinderInternal for T {
		fn prepare_transact(&self) -> Result<Parcel> {
		fn prepare_transact(&self) -> Result<OwnedParcel> {
		let mut input = ptr::null_mut();
		let status = unsafe {
		// Safety: `SpIBinder` guarantees that `self` always contains a
		@@ -253,20 +253,19 @@ impl<T: AsNative<sys::AIBinder>> IBinderInternal for T {

		unsafe {
		// Safety: At this point, `input` is either a valid, owned `AParcel`
		// pointer, or null. `Parcel::owned` safely handles both cases,
		// pointer, or null. `OwnedParcel::from_raw` safely handles both cases,
		// taking ownership of the parcel.
		Parcel::owned(input).ok_or(StatusCode::UNEXPECTED_NULL)
		OwnedParcel::from_raw(input).ok_or(StatusCode::UNEXPECTED_NULL)
		}
		}

		fn submit_transact(
		&self,
		code: TransactionCode,
		data: Parcel,
		data: OwnedParcel,
		flags: TransactionFlags,
		) -> Result<Parcel> {
		) -> Result<OwnedParcel> {
		let mut reply = ptr::null_mut();
		assert!(data.is_owned());
		let status = unsafe {
		// Safety: `SpIBinder` guarantees that `self` always contains a
		// valid pointer to an `AIBinder`. Although `IBinder::transact` is
		@@ -299,9 +298,8 @@ impl<T: AsNative<sys::AIBinder>> IBinderInternal for T {
		// after the call to `AIBinder_transact` above, so we can
		// construct a `Parcel` out of it. `AIBinder_transact` passes
		// ownership of the `reply` parcel to Rust, so we need to
		// construct an owned variant. `Parcel::owned` takes ownership
		// of the parcel pointer.
		Parcel::owned(reply).ok_or(StatusCode::UNEXPECTED_NULL)
		// construct an owned variant.
		OwnedParcel::from_raw(reply).ok_or(StatusCode::UNEXPECTED_NULL)
		}
		}