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Commit e70d6b7c authored by Treehugger Robot's avatar Treehugger Robot Committed by Automerger Merge Worker
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Merge "Add IntoBinderResult trait to simplify binder error handling" into main...

Merge "Add IntoBinderResult trait to simplify binder error handling" into main am: 280e2268 am: 8b8019f8

Original change: https://android-review.googlesource.com/c/platform/frameworks/native/+/2692767



Change-Id: Id76cde0c45abbcbd551f6be594d0bc1c354eb164
Signed-off-by: default avatarAutomerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>
parents c2520d3e 8b8019f8
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+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()
        );
    }
}
+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,