Switch from failure to thiserror.

Author: tyler

Cargo.toml

@@ -6,7 +6,7 @@ edition = "2018"
 
 [dependencies]
 bitflags = "1.0"
-failure = "0.1"
-libc = "=0.2.59"
+libc = "0.2.65"
 nix = "0.13"
+thiserror = "1.0.4"
 userfaultfd-sys = { path = "userfaultfd-sys" }

src/error.rs

@@ -1,5 +1,5 @@
 use crate::IoctlFlags;
-use failure::Fail;
+use thiserror::Error;
 use nix::errno::Errno;
 
 pub type Result<T> = std::result::Result<T, Error>;
@@ -10,38 +10,38 @@ pub type Result<T> = std::result::Result<T, Error>;
 /// [`userfaultfd(2)`](http://man7.org/linux/man-pages/man2/userfaultfd.2.html) and
 /// [`ioctl_userfaultfd(2)`](http://man7.org/linux/man-pages/man2/ioctl_userfaultfd.2.html) for more
 /// details on how to interpret these errors.
-#[derive(Debug, Fail)]
+#[derive(Debug, Error)]
 pub enum Error {
     /// Copy ioctl failure with `errno` value.
-    #[fail(display = "copy failed: {}", 0)]
+    #[error("Copy failed")]
     CopyFailed(Errno),
 
     /// Failure to read a full `uffd_msg` struct from the underlying file descriptor.
-    #[fail(display = "incomplete uffd_msg; read only {}/{} bytes", read, expected)]
+    #[error("Incomplete uffd_msg; read only {read}/{expected} bytes")]
     IncompleteMsg { read: usize, expected: usize },
 
     /// Generic system error.
-    #[fail(display = "system error: {}", 0)]
-    SystemError(nix::Error),
+    #[error("System error")]
+    SystemError(#[source] nix::Error),
 
     /// End-of-file was read from the underlying file descriptor.
-    #[fail(display = "EOF when reading file descriptor")]
+    #[error("EOF when reading file descriptor")]
     ReadEof,
 
     /// An unrecognized event code was found in a `uffd_msg` struct.
-    #[fail(display = "unrecognized event in uffd_msg: {}", 0)]
+    #[error("Unrecognized event in uffd_msg: {0}")]
     UnrecognizedEvent(u8),
 
     /// An unrecognized ioctl bit was set in the result of API initialization or registration.
-    #[fail(display = "unrecognized ioctl flags: {}", 0)]
+    #[error("Unrecognized ioctl flags: {0}")]
     UnrecognizedIoctls(u64),
 
     /// Requested ioctls were not available when initializing the API.
-    #[fail(display = "requested ioctls unsupported; supported: {:?}", 0)]
+    #[error("Requested ioctls unsupported; supported: {0:?}")]
     UnsupportedIoctls(IoctlFlags),
 
     /// Zeropage ioctl failure with `errno` value.
-    #[fail(display = "zeropage failed: {}", 0)]
+    #[error("Zeropage failed: {0}")]
     ZeropageFailed(Errno),
 }