gpu_display: convert to ThisError and sort

BUG=b:197143586
TEST=cargo check

Change-Id: I461144d021314984e9ec2c738144b8e3065efcf4
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3105079
Reviewed-by: Gurchetan Singh <gurchetansingh@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Commit-Queue: Daniel Verkamp <dverkamp@chromium.org>

Cargo.lock

@@ -535,6 +535,8 @@ dependencies = [
  "libc",
  "linux_input_sys",
  "pkg-config",
+ "remain",
+ "thiserror",
 ]
 
 [[package]]

gpu_display/Cargo.toml

@@ -12,6 +12,8 @@ data_model = { path = "../data_model" }
 libc = "*"
 base = { path = "../base" }
 linux_input_sys = { path = "../linux_input_sys" }
+remain = "*"
+thiserror = "*"
 
 [build-dependencies]
 cc = "=1.0.25"

gpu_display/src/lib.rs

@@ -6,13 +6,14 @@
 //! Wayland or X.
 
 use std::collections::BTreeMap;
-use std::fmt::{self, Display};
 use std::io::Error as IoError;
 use std::path::Path;
 use std::time::Duration;
 
 use base::{AsRawDescriptor, Error as BaseError, EventType, PollToken, RawDescriptor, WaitContext};
 use data_model::VolatileSlice;
+use remain::sorted;
+use thiserror::Error;
 
 mod event_device;
 mod gpu_display_stub;
@@ -26,57 +27,49 @@ pub use event_device::{EventDevice, EventDeviceKind};
 use linux_input_sys::virtio_input_event;
 
 /// An error generated by `GpuDisplay`.
-#[derive(Debug)]
+#[sorted]
+#[derive(Error, Debug)]
 pub enum GpuDisplayError {
     /// An internal allocation failed.
+    #[error("internal allocation failed")]
     Allocate,
+    /// A base error occurred.
+    #[error("received a base error: {0}")]
+    BaseError(BaseError),
     /// Connecting to the compositor failed.
+    #[error("failed to connect to compositor")]
     Connect,
     /// Creating event file descriptor failed.
+    #[error("failed to create event file descriptor")]
     CreateEvent,
-    /// A base error occurred.
-    BaseError(BaseError),
     /// Failed to create a surface on the compositor.
+    #[error("failed to crate surface on the compositor")]
     CreateSurface,
     /// Failed to import a buffer to the compositor.
+    #[error("failed to import a buffer to the compositor")]
     FailedImport,
-    /// The path is invalid.
-    InvalidPath,
     /// The import ID is invalid.
+    #[error("invalid import ID")]
     InvalidImportId,
+    /// The path is invalid.
+    #[error("invalid path")]
+    InvalidPath,
     /// The surface ID is invalid.
+    #[error("invalid surface ID")]
     InvalidSurfaceId,
     /// An input/output error occured.
+    #[error("an input/output error occur: {0}")]
     IoError(IoError),
     /// A required feature was missing.
+    #[error("required feature was missing: {0}")]
     RequiredFeature(&'static str),
     /// The method is unsupported by the implementation.
+    #[error("unsupported by the implementation")]
     Unsupported,
 }
 
 pub type GpuDisplayResult<T> = std::result::Result<T, GpuDisplayError>;
 
-impl Display for GpuDisplayError {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        use self::GpuDisplayError::*;
-
-        match self {
-            Allocate => write!(f, "internal allocation failed"),
-            Connect => write!(f, "failed to connect to compositor"),
-            CreateEvent => write!(f, "failed to create event file descriptor"),
-            BaseError(e) => write!(f, "received a base error: {}", e),
-            CreateSurface => write!(f, "failed to crate surface on the compositor"),
-            FailedImport => write!(f, "failed to import a buffer to the compositor"),
-            InvalidPath => write!(f, "invalid path"),
-            InvalidImportId => write!(f, "invalid import ID"),
-            InvalidSurfaceId => write!(f, "invalid surface ID"),
-            IoError(e) => write!(f, "an input/output error occur: {}", e),
-            RequiredFeature(feature) => write!(f, "required feature was missing: {}", feature),
-            Unsupported => write!(f, "unsupported by the implementation"),
-        }
-    }
-}
-
 impl From<BaseError> for GpuDisplayError {
     fn from(e: BaseError) -> GpuDisplayError {
         GpuDisplayError::BaseError(e)