arch: serial: Use thiserror and sorted for Error enum

BUG=none
TEST=cargo check

Change-Id: Ib8c07eb54af730c7a0ffaab67c02d6fb14a7efa5
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3096438
Tested-by: kokoro <noreply+kokoro@google.com>
Commit-Queue: Keiichi Watanabe <keiichiw@chromium.org>
Reviewed-by: Chirantan Ekbote <chirantan@chromium.org>

Cargo.lock

@@ -54,6 +54,7 @@ dependencies = [
  "libc",
  "minijail",
  "power_monitor",
+ "remain",
  "resources",
  "sync",
  "thiserror",

arch/Cargo.toml

@@ -10,16 +10,17 @@ gdb = ["gdbstub_arch"]
 
 [dependencies]
 acpi_tables = { path = "../acpi_tables" }
+base = { path = "../base" }
 devices = { path = "../devices" }
 gdbstub_arch = { version = "0.1.0", optional = true }
 hypervisor = { path = "../hypervisor" }
 kernel_cmdline = { path = "../kernel_cmdline" }
 libc = "*"
 minijail = "*"
+power_monitor = { path = "../power_monitor" }
+remain = "*"
 resources = { path = "../resources" }
 sync = { path = "../sync" }
-base = { path = "../base" }
+thiserror = "1.0.20"
 vm_control = { path = "../vm_control" }
 vm_memory = { path = "../vm_memory" }
-power_monitor = { path = "../power_monitor" }
-thiserror = "1.0.20"

arch/src/fdt.rs

@@ -11,28 +11,30 @@ use std::ffi::CString;
 use std::io;
 use std::mem::size_of;
 
+use remain::sorted;
 use thiserror::Error as ThisError;
 
+#[sorted]
 #[derive(ThisError, Debug)]
 pub enum Error {
+    #[error("Parse error reading FDT parameters")]
+    FdtFileParseError,
+    #[error("Error writing FDT to guest memory")]
+    FdtGuestMemoryWriteError,
+    #[error("I/O error reading FDT parameters code={0}")]
+    FdtIoError(io::Error),
+    #[error("Strings cannot contain NUL")]
+    InvalidString,
+    #[error("Attempted to end a node that was not the most recent")]
+    OutOfOrderEndNode,
     #[error("Properties may not be added after a node has been ended")]
     PropertyAfterEndNode,
     #[error("Property value size must fit in 32 bits")]
     PropertyValueTooLarge,
     #[error("Total size must fit in 32 bits")]
     TotalSizeTooLarge,
-    #[error("Strings cannot contain NUL")]
-    InvalidString,
-    #[error("Attempted to end a node that was not the most recent")]
-    OutOfOrderEndNode,
     #[error("Attempted to call finish without ending all nodes")]
     UnclosedNode,
-    #[error("Error writing FDT to guest memory")]
-    FdtGuestMemoryWriteError,
-    #[error("Parse error reading FDT parameters")]
-    FdtFileParseError,
-    #[error("I/O error reading FDT parameters code={0}")]
-    FdtIoError(io::Error),
 }
 
 pub type Result<T> = std::result::Result<T, Error>;

arch/src/serial.rs

@@ -17,39 +17,33 @@ use std::time::Duration;
 use base::{error, info, read_raw_stdin, syslog, AsRawDescriptor, Event, RawDescriptor};
 use devices::{Bus, ProtectionType, ProxyDevice, Serial, SerialDevice};
 use minijail::Minijail;
+use remain::sorted;
 use sync::Mutex;
+use thiserror::Error as ThisError;
 
 use crate::DeviceRegistrationError;
 
-#[derive(Debug)]
+#[sorted]
+#[derive(ThisError, Debug)]
 pub enum Error {
+    #[error("Unable to clone an Event: {0}")]
     CloneEvent(base::Error),
+    #[error("Unable to open/create file: {0}")]
     FileError(std::io::Error),
-    InvalidSerialHardware(String),
-    InvalidSerialType(String),
+    #[error("Serial device path is invalid")]
     InvalidPath,
+    #[error("Invalid serial hardware: {0}")]
+    InvalidSerialHardware(String),
+    #[error("Invalid serial type: {0}")]
+    InvalidSerialType(String),
+    #[error("Serial device type file requires a path")]
     PathRequired,
+    #[error("Failed to create unbound socket")]
     SocketCreateFailed,
+    #[error("Serial device type {0} not implemented")]
     Unimplemented(SerialType),
 }
 
-impl Display for Error {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        use self::Error::*;
-
-        match self {
-            CloneEvent(e) => write!(f, "unable to clone an Event: {}", e),
-            FileError(e) => write!(f, "unable to open/create file: {}", e),
-            InvalidSerialHardware(e) => write!(f, "invalid serial hardware: {}", e),
-            InvalidSerialType(e) => write!(f, "invalid serial type: {}", e),
-            InvalidPath => write!(f, "serial device path is invalid"),
-            PathRequired => write!(f, "serial device type file requires a path"),
-            SocketCreateFailed => write!(f, "failed to create unbound socket"),
-            Unimplemented(e) => write!(f, "serial device type {} not implemented", e.to_string()),
-        }
-    }
-}
-
 /// Enum for possible type of serial devices
 #[derive(Clone, Debug)]
 pub enum SerialType {
@@ -462,25 +456,15 @@ pub fn add_serial_devices(
     Ok(())
 }
 
-#[derive(Debug)]
+#[sorted]
+#[derive(ThisError, Debug)]
 pub enum GetSerialCmdlineError {
+    #[error("Error appending to cmdline: {0}")]
     KernelCmdline(kernel_cmdline::Error),
+    #[error("Hardware {0} not supported as earlycon")]
     UnsupportedEarlyconHardware(SerialHardware),
 }
 
-impl Display for GetSerialCmdlineError {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        use self::GetSerialCmdlineError::*;
-
-        match self {
-            KernelCmdline(e) => write!(f, "error appending to cmdline: {}", e),
-            UnsupportedEarlyconHardware(hw) => {
-                write!(f, "hardware {} not supported as earlycon", hw)
-            }
-        }
-    }
-}
-
 pub type GetSerialCmdlineResult<T> = std::result::Result<T, GetSerialCmdlineError>;
 
 /// Add serial options to the provided `cmdline` based on `serial_parameters`.