Merge "Add IntoBinderResult trait to simplify binder error handling" into main... (192e8b4a) · Commits · e / os / android_frameworks_native

libs/binder/rust/src/error.rs

+150 −0

Original line number	Original line	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)]		#[cfg(test)]
	mod tests {		mod tests {
	use super::*;		use super::*;
	@@ -406,4 +494,66 @@ mod tests {
	assert_eq!(status.service_specific_error(), 0);		assert_eq!(status.service_specific_error(), 0);
	assert_eq!(status.get_description(), "Status(-5, EX_ILLEGAL_STATE): ''".to_string());		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	Original line	Diff line number	Diff line
	@@ -106,7 +106,7 @@ use binder_ndk_sys as sys;

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