binder_rs: Add Parcelable trait
Adds Parcelable trait that all auto-generated Rust parcelables
implement. This trait provides the get_descriptor() and
get_stability(), as well as internal serialization and
deserialization methods specific to parcelables.
Bug: 169035750
Test: m
Change-Id: Ib97ac4d79cd9829ab3968076492ac1f28f27e8ff
diff --git a/libs/binder/rust/src/parcel.rs b/libs/binder/rust/src/parcel.rs
index dad89ec..8e6c94c 100644
--- a/libs/binder/rust/src/parcel.rs
+++ b/libs/binder/rust/src/parcel.rs
@@ -33,6 +33,7 @@
pub use self::file_descriptor::ParcelFileDescriptor;
pub use self::parcelable::{
Deserialize, DeserializeArray, DeserializeOption, Serialize, SerializeArray, SerializeOption,
+ Parcelable,
};
/// Container for a message (data and object references) that can be sent
diff --git a/libs/binder/rust/src/parcel/parcelable.rs b/libs/binder/rust/src/parcel/parcelable.rs
index 8e99081..cbba673 100644
--- a/libs/binder/rust/src/parcel/parcelable.rs
+++ b/libs/binder/rust/src/parcel/parcelable.rs
@@ -27,6 +27,29 @@
use std::ptr;
use std::slice;
+/// Super-trait for Binder parcelables.
+///
+/// This trait is equivalent `android::Parcelable` in C++,
+/// and defines a common interface that all parcelables need
+/// to implement.
+pub trait Parcelable {
+ /// Internal serialization function for parcelables.
+ ///
+ /// This method is mainly for internal use.
+ /// `Serialize::serialize` and its variants are generally
+ /// preferred over this function, since the former also
+ /// prepend a header.
+ fn write_to_parcel(&self, parcel: &mut Parcel) -> Result<()>;
+
+ /// Internal deserialization function for parcelables.
+ ///
+ /// This method is mainly for internal use.
+ /// `Deserialize::deserialize` and its variants are generally
+ /// preferred over this function, since the former also
+ /// parse the additional header.
+ fn read_from_parcel(&mut self, parcel: &Parcel) -> Result<()>;
+}
+
/// A struct whose instances can be written to a [`Parcel`].
// Might be able to hook this up as a serde backend in the future?
pub trait Serialize {
@@ -711,19 +734,53 @@
}
}
+/// Implement `Serialize` trait and friends for a parcelable
+///
+/// This is an internal macro used by the AIDL compiler to implement
+/// `Serialize`, `SerializeArray` and `SerializeOption` for
+/// structured parcelables. The target type must implement the
+/// `Parcelable` trait.
+/// ```
+#[macro_export]
+macro_rules! impl_serialize_for_parcelable {
+ ($parcelable:ident) => {
+ impl $crate::parcel::Serialize for $parcelable {
+ fn serialize(
+ &self,
+ parcel: &mut $crate::parcel::Parcel,
+ ) -> $crate::Result<()> {
+ <Self as $crate::parcel::SerializeOption>::serialize_option(
+ Some(self),
+ parcel,
+ )
+ }
+ }
+
+ impl $crate::parcel::SerializeArray for $parcelable {}
+
+ impl $crate::parcel::SerializeOption for $parcelable {
+ fn serialize_option(
+ this: Option<&Self>,
+ parcel: &mut $crate::parcel::Parcel,
+ ) -> $crate::Result<()> {
+ if let Some(this) = this {
+ use $crate::parcel::Parcelable;
+ parcel.write(&1i32)?;
+ this.write_to_parcel(parcel)
+ } else {
+ parcel.write(&0i32)
+ }
+ }
+ }
+ }
+}
+
/// Implement `Deserialize` trait and friends for a parcelable
///
/// This is an internal macro used by the AIDL compiler to implement
/// `Deserialize`, `DeserializeArray` and `DeserializeOption` for
-/// structured parcelables. The target type must implement a
-/// `deserialize_parcelable` method with the following signature:
-/// ```no_run
-/// fn deserialize_parcelable(
-/// &mut self,
-/// parcel: &binder::parcel::Parcelable,
-/// ) -> binder::Result<()> {
-/// // ...
-/// }
+/// structured parcelables. The target type must implement the
+/// `Parcelable` trait.
/// ```
#[macro_export]
macro_rules! impl_deserialize_for_parcelable {
@@ -744,7 +801,8 @@
if status == 0 {
Err($crate::StatusCode::UNEXPECTED_NULL)
} else {
- self.deserialize_parcelable(parcel)
+ use $crate::parcel::Parcelable;
+ self.read_from_parcel(parcel)
}
}
}
@@ -768,8 +826,9 @@
*this = None;
Ok(())
} else {
+ use $crate::parcel::Parcelable;
this.get_or_insert_with(Self::default)
- .deserialize_parcelable(parcel)
+ .read_from_parcel(parcel)
}
}
}