Merge "Add IntoBinderResult trait to simplify binder error handling" into main (280e2268) · Commits · e / os / android_frameworks_native

libs/binder/rust/src/error.rs

+150 −0

Original line number	Diff line number	Diff line
		@@ -370,6 +370,94 @@ unsafe impl AsNative<sys::AStatus> for Status {
		}
		}

		/// A conversion from `std::result::Result<T, E>` to `binder::Result<T>`. If this type is `Ok(T)`,
		/// it's returned as is. If this type is `Err(E)`, `E` is converted into `Status` which can be
		/// either a general binder exception, or a service-specific exception.
		///
		/// # Examples
		///
		/// ```
		/// // std::io::Error is formatted as the exception's message
		/// fn file_exists(name: &str) -> binder::Result<bool> {
		/// std::fs::metadata(name)
		/// .or_service_specific_exception(NOT_FOUND)?
		/// }
		///
		/// // A custom function is used to create the exception's message
		/// fn file_exists(name: &str) -> binder::Result<bool> {
		/// std::fs::metadata(name)
		/// .or_service_specific_exception_with(NOT_FOUND,
		/// \|e\| format!("file {} not found: {:?}", name, e))?
		/// }
		///
		/// // anyhow::Error is formatted as the exception's message
		/// use anyhow::{Context, Result};
		/// fn file_exists(name: &str) -> binder::Result<bool> {
		/// std::fs::metadata(name)
		/// .context("file {} not found")
		/// .or_service_specific_exception(NOT_FOUND)?
		/// }
		///
		/// // General binder exceptions can be created similarly
		/// fn file_exists(name: &str) -> binder::Result<bool> {
		/// std::fs::metadata(name)
		/// .or_binder_exception(ExceptionCode::ILLEGAL_ARGUMENT)?
		/// }
		/// ```
		pub trait IntoBinderResult<T, E> {
		/// Converts the embedded error into a general binder exception of code `exception`. The
		/// message of the exception is set by formatting the error for debugging.
		fn or_binder_exception(self, exception: ExceptionCode) -> result::Result<T, Status>;

		/// Converts the embedded error into a general binder exception of code `exception`. The
		/// message of the exception is set by lazily evaluating the `op` function.
		fn or_binder_exception_with<M: AsRef<str>, O: FnOnce(E) -> M>(
		self,
		exception: ExceptionCode,
		op: O,
		) -> result::Result<T, Status>;

		/// Converts the embedded error into a service-specific binder exception. `error_code` is used
		/// to distinguish different service-specific binder exceptions. The message of the exception
		/// is set by formatting the error for debugging.
		fn or_service_specific_exception(self, error_code: i32) -> result::Result<T, Status>;

		/// Converts the embedded error into a service-specific binder exception. `error_code` is used
		/// to distinguish different service-specific binder exceptions. The message of the exception
		/// is set by lazily evaluating the `op` function.
		fn or_service_specific_exception_with<M: AsRef<str>, O: FnOnce(E) -> M>(
		self,
		error_code: i32,
		op: O,
		) -> result::Result<T, Status>;
		}

		impl<T, E: std::fmt::Debug> IntoBinderResult<T, E> for result::Result<T, E> {
		fn or_binder_exception(self, exception: ExceptionCode) -> result::Result<T, Status> {
		self.or_binder_exception_with(exception, \|e\| format!("{:?}", e))
		}

		fn or_binder_exception_with<M: AsRef<str>, O: FnOnce(E) -> M>(
		self,
		exception: ExceptionCode,
		op: O,
		) -> result::Result<T, Status> {
		self.map_err(\|e\| Status::new_exception_str(exception, Some(op(e))))
		}

		fn or_service_specific_exception(self, error_code: i32) -> result::Result<T, Status> {
		self.or_service_specific_exception_with(error_code, \|e\| format!("{:?}", e))
		}

		fn or_service_specific_exception_with<M: AsRef<str>, O: FnOnce(E) -> M>(
		self,
		error_code: i32,
		op: O,
		) -> result::Result<T, Status> {
		self.map_err(\|e\| Status::new_service_specific_error_str(error_code, Some(op(e))))
		}
		}

		#[cfg(test)]
		mod tests {
		use super::*;
		@@ -406,4 +494,66 @@ mod tests {
		assert_eq!(status.service_specific_error(), 0);
		assert_eq!(status.get_description(), "Status(-5, EX_ILLEGAL_STATE): ''".to_string());
		}

		#[test]
		fn convert_to_service_specific_exception() {
		let res: std::result::Result<(), Status> =
		Err("message").or_service_specific_exception(-42);

		assert!(res.is_err());
		let status = res.unwrap_err();
		assert_eq!(status.exception_code(), ExceptionCode::SERVICE_SPECIFIC);
		assert_eq!(status.service_specific_error(), -42);
		assert_eq!(
		status.get_description(),
		"Status(-8, EX_SERVICE_SPECIFIC): '-42: \"message\"'".to_string()
		);
		}

		#[test]
		fn convert_to_service_specific_exception_with() {
		let res: std::result::Result<(), Status> = Err("message")
		.or_service_specific_exception_with(-42, \|e\| format!("outer message: {:?}", e));

		assert!(res.is_err());
		let status = res.unwrap_err();
		assert_eq!(status.exception_code(), ExceptionCode::SERVICE_SPECIFIC);
		assert_eq!(status.service_specific_error(), -42);
		assert_eq!(
		status.get_description(),
		"Status(-8, EX_SERVICE_SPECIFIC): '-42: outer message: \"message\"'".to_string()
		);
		}

		#[test]
		fn convert_to_binder_exception() {
		let res: std::result::Result<(), Status> =
		Err("message").or_binder_exception(ExceptionCode::ILLEGAL_STATE);

		assert!(res.is_err());
		let status = res.unwrap_err();
		assert_eq!(status.exception_code(), ExceptionCode::ILLEGAL_STATE);
		assert_eq!(status.service_specific_error(), 0);
		assert_eq!(
		status.get_description(),
		"Status(-5, EX_ILLEGAL_STATE): '\"message\"'".to_string()
		);
		}

		#[test]
		fn convert_to_binder_exception_with() {
		let res: std::result::Result<(), Status> = Err("message")
		.or_binder_exception_with(ExceptionCode::ILLEGAL_STATE, \|e\| {
		format!("outer message: {:?}", e)
		});

		assert!(res.is_err());
		let status = res.unwrap_err();
		assert_eq!(status.exception_code(), ExceptionCode::ILLEGAL_STATE);
		assert_eq!(status.service_specific_error(), 0);
		assert_eq!(
		status.get_description(),
		"Status(-5, EX_ILLEGAL_STATE): 'outer message: \"message\"'".to_string()
		);
		}
		}

libs/binder/rust/src/lib.rs

+1 −1

Original line number	Diff line number	Diff line
		@@ -106,7 +106,7 @@ use binder_ndk_sys as sys;

		pub use crate::binder_async::{BinderAsyncPool, BoxFuture};
		pub use binder::{BinderFeatures, FromIBinder, IBinder, Interface, Strong, Weak};
		pub use error::{ExceptionCode, Status, StatusCode};
		pub use error::{ExceptionCode, IntoBinderResult, Status, StatusCode};
		pub use native::{
		add_service, force_lazy_services_persist, is_handling_transaction, register_lazy_service,
		LazyServiceGuard,