firmware: use the failure crate in libio.

artiq/firmware/Cargo.lock

@@ -98,6 +98,21 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 name = "dyld"
 version = "0.0.0"
 
+[[package]]
+name = "failure"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "failure_derive"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "synstructure 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "fringe"
 version = "1.1.0"
@@ -111,6 +126,8 @@ name = "io"
 version = "0.0.0"
 dependencies = [
  "byteorder 1.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure_derive 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -191,6 +208,11 @@ dependencies = [
  "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "quote"
+version = "0.3.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "runtime"
 version = "0.0.0"
@@ -247,6 +269,38 @@ dependencies = [
 name = "std_artiq"
 version = "0.0.0"
 
+[[package]]
+name = "syn"
+version = "0.11.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "synom 0.11.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-xid 0.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "synom"
+version = "0.11.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "unicode-xid 0.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "synstructure"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "unicode-xid"
+version = "0.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "unwind_backtrace"
 version = "0.0.0"
@@ -280,6 +334,8 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum compiler_builtins 0.1.0 (git+https://github.com/rust-lang-nursery/compiler-builtins)" = "<none>"
 "checksum crc 1.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "bd5d02c0aac6bd68393ed69e00bbc2457f3e89075c6349db7189618dc4ddc1d7"
 "checksum cslice 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "0f8cb7306107e4b10e64994de6d3274bd08996a7c1322a27b86482392f96be0a"
+"checksum failure 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "934799b6c1de475a012a02dab0ace1ace43789ee4b99bcfbf1a2e3e8ced5de82"
+"checksum failure_derive 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "c7cdda555bb90c9bb67a3b670a0f42de8e73f5981524123ad8578aafec8ddb8b"
 "checksum fringe 1.1.0 (git+https://github.com/m-labs/libfringe?rev=bd23494)" = "<none>"
 "checksum kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "7507624b29483431c0ba2d82aece8ca6cdba9382bff4ddd0f7490560c056098d"
 "checksum libc 0.2.40 (registry+https://github.com/rust-lang/crates.io-index)" = "6fd41f331ac7c5b8ac259b8bf82c75c0fb2e469bbf37d2becbba9a6a2221965b"
@@ -288,8 +344,13 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum log_buffer 1.2.0 (git+https://github.com/whitequark/rust-log_buffer?rev=rust-1.25)" = "<none>"
 "checksum managed 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "43e2737ecabe4ae36a68061398bf27d2bfd0763f4c3c837a398478459494c4b7"
 "checksum managed 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)" = "5a31885241e61ba264d780d2e6686e7e59561c947b4581470364eb3e10102d86"
+"checksum quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)" = "7a6e920b65c65f10b2ae65c831a81a073a89edd28c7cce89475bff467ab4167a"
 "checksum same-file 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "d931a44fdaa43b8637009e7632a02adc4f2b2e0733c08caa4cf00e8da4a117a7"
 "checksum smoltcp 0.4.0 (git+https://github.com/m-labs/smoltcp?rev=181083f)" = "<none>"
+"checksum syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)" = "d3b891b9015c88c576343b9b3e41c2c11a51c219ef067b264bd9c8aa9b441dad"
+"checksum synom 0.11.3 (registry+https://github.com/rust-lang/crates.io-index)" = "a393066ed9010ebaed60b9eafa373d4b1baac186dd7e008555b0f702b51945b6"
+"checksum synstructure 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)" = "3a761d12e6d8dcb4dcf952a7a89b475e3a9d69e4a69307e01a470977642914bd"
+"checksum unicode-xid 0.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "8c1f860d7d29cf02cb2f3f359fd35991af3d30bac52c57d265a3c461074cb4dc"
 "checksum walkdir 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)" = "bb08f9e670fab86099470b97cd2b252d6527f0b3cc1401acdb595ffc9dd288ff"
 "checksum winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "167dc9d6949a9b857f3451275e911c3f44255842c1f7a76f33c55103a909087a"
 "checksum winapi-build 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "2d315eee3b34aca4797b2da6b13ed88266e6d612562a0c46390af8299fc699bc"

artiq/firmware/libio/Cargo.toml

@@ -8,6 +8,8 @@ name = "io"
 path = "lib.rs"
 
 [dependencies]
+failure = { version = "0.1", default-features = false }
+failure_derive = { version = "0.1", default-features = false }
 byteorder = { version = "1.0", default-features = false, optional = true }
 
 [features]

artiq/firmware/libio/lib.rs

@@ -2,6 +2,9 @@
 #![feature(never_type)]
 #![cfg_attr(feature = "alloc", feature(alloc))]
 
+extern crate failure;
+#[macro_use]
+extern crate failure_derive;
 #[cfg(feature = "alloc")]
 #[macro_use]
 extern crate alloc;
@@ -9,7 +12,6 @@ extern crate alloc;
 extern crate byteorder;
 
 use core::result;
-use core::fmt;
 
 mod cursor;
 #[cfg(feature = "byteorder")]
@@ -19,24 +21,14 @@ pub use cursor::Cursor;
 
 pub type Result<T, E> = result::Result<T, Error<E>>;
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[derive(Fail, Debug, Clone, PartialEq)]
 pub enum Error<T> {
+    #[fail(display = "unexpected end of stream")]
     UnexpectedEof,
+    #[fail(display = "unrecognized input")]
     Unrecognized,
-    Other(T)
+    #[fail(display = "{}", _0)]
-}
+    Other(#[cause] T)
-
-impl<T: fmt::Display> fmt::Display for Error<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        match self {
-            &Error::UnexpectedEof =>
-                write!(f, "unexpected end of stream"),
-            &Error::Unrecognized =>
-                write!(f, "unrecognized input"),
-            &Error::Other(ref err) =>
-                write!(f, "{}", err)
-        }
-    }
 }
 
 impl<T> From<T> for Error<T> {

artiq/firmware/libio/proto.rs

@@ -1,30 +1,18 @@
 #[cfg(feature = "alloc")]
-use core::fmt;
+use {core::str::Utf8Error, alloc::String};
-#[cfg(feature = "alloc")]
-use alloc::string;
 use byteorder::{ByteOrder, NetworkEndian};
 
 use ::{Read, Write, Error as IoError};
 
 #[cfg(feature = "alloc")]
-#[derive(Debug)]
+#[derive(Fail, Debug, Clone, PartialEq)]
 pub enum ReadStringError<T> {
-    Utf8Error(string::FromUtf8Error),
+    #[fail(display = "invalid UTF-8: {}", _0)]
+    Utf8Error(Utf8Error),
+    #[fail(display = "{}", _0)]
     Other(T)
 }
 
-#[cfg(feature = "alloc")]
-impl<T: fmt::Display> fmt::Display for ReadStringError<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        match self {
-            &ReadStringError::Utf8Error(ref err) =>
-                write!(f, "invalid UTF-8 ({})", err),
-            &ReadStringError::Other(ref err) =>
-                write!(f, "{}", err)
-        }
-    }
-}
-
 #[cfg(feature = "alloc")]
 impl<T> From<ReadStringError<IoError<T>>> for IoError<T>
 {
@@ -86,14 +74,8 @@ pub trait ProtoRead {
     #[cfg(feature = "alloc")]
     #[inline]
     fn read_string(&mut self) -> Result<::alloc::String, ReadStringError<Self::ReadError>> {
-        match self.read_bytes() {
+        let bytes = self.read_bytes().map_err(ReadStringError::Other)?;
-            Ok(bytes) =>
+        String::from_utf8(bytes).map_err(|err| ReadStringError::Utf8Error(err.utf8_error()))
-                match ::alloc::String::from_utf8(bytes) {
-                    Ok(string) => Ok(string),
-                    Err(err) => Err(ReadStringError::Utf8Error(err))
-                },
-            Err(err) => Err(ReadStringError::Other(err))
-        }
     }
 }