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android / platform / external / rust / crates / remain / refs/heads/android11-mainline-captiveportallogin-release
commitdc3071e3317ddbac7633c7438ee98a41398e62af[log] [tgz]
authorXin Li <delphij@google.com>Wed Oct 30 14:25:02 2019 -0700
committerandroid-build-merger <android-build-merger@google.com>Wed Oct 30 14:25:02 2019 -0700
tree383c3e355db0910ba3a513b1f837375c5656106b
parent77cb85583fe28328f2a1f6e7e5b04808a712450c [diff]
parent8ed7a370bef4647c82fe5b22b0696ddc715b706b [diff]
[automerger skipped] DO NOT MERGE - qt-qpr1-dev-plus-aosp-without-vendor@5915889 into stage-aosp-master am: d921a46f26
am: 8ed7a370be -s ours
am skip reason: subject contains skip directive

Change-Id: Ib2581c0626d0f89c70dd04671bb15dd9d51ad1a7
tree: 383c3e355db0910ba3a513b1f837375c5656106b
  1. src/
  2. tests/
  3. .cargo_vcs_info.json
  4. .gitignore
  5. .travis.yml
  6. Android.bp
  7. Cargo.toml
  8. Cargo.toml.orig
  9. LICENSE-APACHE
  10. LICENSE-MIT
  11. README.md
README.md

Remain sorted

Build Status Latest Version Rust Documentation

This crate provides an attribute macro to check at compile time that the variants of an enum or the arms of a match expression are written in sorted order.

[dependencies]
remain = "0.1"

Syntax

Place a #[remain::sorted] attribute on enums, structs, match-expressions, or let-statements whose value is a match-expression.

Alternatively, import as use remain::sorted; and use #[sorted] as the attribute.

#[remain::sorted]
#[derive(Debug)]
pub enum Error {
    BlockSignal(signal::Error),
    CreateCrasClient(libcras::Error),
    CreateEventFd(sys_util::Error),
    CreateSignalFd(sys_util::SignalFdError),
    CreateSocket(io::Error),
    DetectImageType(qcow::Error),
    DeviceJail(io_jail::Error),
    NetDeviceNew(virtio::NetError),
    SpawnVcpu(io::Error),
}

#[remain::sorted]
#[derive(Debug)]
pub enum Registers {
    ax: u16,
    cx: u16,
    di: u16,
    si: u16,
    sp: u16,
}

impl Display for Error {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        use self::Error::*;

        #[remain::sorted]
        match self {
            BlockSignal(e) => write!(f, "failed to block signal: {}", e),
            CreateCrasClient(e) => write!(f, "failed to create cras client: {}", e),
            CreateEventFd(e) => write!(f, "failed to create eventfd: {}", e),
            CreateSignalFd(e) => write!(f, "failed to create signalfd: {}", e),
            CreateSocket(e) => write!(f, "failed to create socket: {}", e),
            DetectImageType(e) => write!(f, "failed to detect disk image type: {}", e),
            DeviceJail(e) => write!(f, "failed to jail device: {}", e),
            NetDeviceNew(e) => write!(f, "failed to set up virtio networking: {}", e),
            SpawnVcpu(e) => write!(f, "failed to spawn VCPU thread: {}", e),
        }
    }
}

If an enum variant, struct field, or match arm is inserted out of order,

      NetDeviceNew(virtio::NetError),
      SpawnVcpu(io::Error),
+     AaaUhOh(Box<dyn StdError>),
  }

then the macro produces a compile error.

error: AaaUhOh should sort before BlockSignal
  --> tests/stable.rs:49:5
   |
49 |     AaaUhOh(Box<dyn StdError>),
   |     ^^^^^^^

Compiler support

The attribute on enums and structs is supported on any rustc version 1.31+.

Rust does not yet have stable support for user-defined attributes within a function body, so the attribute on match-expressions and let-statements requires a nightly compiler and the following two features enabled:

#![feature(proc_macro_hygiene, stmt_expr_attributes)]

As a stable alternative, this crate provides a function-level attribute called #[remain::check] which makes match-expression and let-statement attributes work on any rustc version 1.31+. Place this attribute on any function containing #[sorted] to make them work on a stable compiler.

impl Display for Error {
    #[remain::check]
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        use self::Error::*;

        #[sorted]
        match self {
            /* ... */
        }
    }
}

License