From 957c434b67b5e1e294b659f6aac31d5d4108beca Mon Sep 17 00:00:00 2001
From: Pat Hickey <pat@moreproductive.org>
Date: Mon, 25 Jan 2021 12:14:27 -0800
Subject: [PATCH] ErrorExt: trap convenience method

---
 crates/wasi-c2/cap-std-sync/src/sched/windows.rs | 10 +++++-----
 crates/wasi-c2/src/error.rs                      |  4 ++++
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/crates/wasi-c2/cap-std-sync/src/sched/windows.rs b/crates/wasi-c2/cap-std-sync/src/sched/windows.rs
index 8b7bdd3317..9d22acd3b0 100644
--- a/crates/wasi-c2/cap-std-sync/src/sched/windows.rs
+++ b/crates/wasi-c2/cap-std-sync/src/sched/windows.rs
@@ -1,4 +1,4 @@
-use anyhow::{anyhow, Context};
+use anyhow::Context;
 use std::ops::Deref;
 use std::os::windows::io::{AsRawHandle, RawHandle};
 use std::sync::mpsc::{self, Receiver, RecvTimeoutError, Sender, TryRecvError};
@@ -69,7 +69,7 @@ impl WasiSched for SyncSched {
             };
             let state = STDIN_POLL
                 .lock()
-                .map_err(|_| anyhow!("failed to take lock of STDIN_POLL"))?
+                .map_err(|_| Error::trap("failed to take lock of STDIN_POLL"))?
                 .poll(waitmode)?;
             for readsub in stdin_read_subs.into_iter() {
                 match state {
@@ -206,7 +206,7 @@ impl StdinPoll {
             // Clean up possibly unread result from previous poll.
             Ok(_) | Err(TryRecvError::Empty) => {}
             Err(TryRecvError::Disconnected) => {
-                return Err(anyhow!("StdinPoll notify_rx channel closed"))
+                return Err(Error::trap("StdinPoll notify_rx channel closed"))
             }
         }
 
@@ -221,7 +221,7 @@ impl StdinPoll {
                 Ok(r) => Ok(r),
                 Err(RecvTimeoutError::Timeout) => Ok(PollState::TimedOut),
                 Err(RecvTimeoutError::Disconnected) => {
-                    Err(anyhow!("StdinPoll notify_rx channel closed"))
+                    Err(Error::trap("StdinPoll notify_rx channel closed"))
                 }
             },
             WaitMode::Infinite => self
@@ -232,7 +232,7 @@ impl StdinPoll {
                 Ok(r) => Ok(r),
                 Err(TryRecvError::Empty) => Ok(PollState::NotReady),
                 Err(TryRecvError::Disconnected) => {
-                    Err(anyhow!("StdinPoll notify_rx channel closed"))
+                    Err(Error::trap("StdinPoll notify_rx channel closed"))
                 }
             },
         }
diff --git a/crates/wasi-c2/src/error.rs b/crates/wasi-c2/src/error.rs
index 44bcab1795..7dd620a9e4 100644
--- a/crates/wasi-c2/src/error.rs
+++ b/crates/wasi-c2/src/error.rs
@@ -48,6 +48,7 @@ pub enum ErrorKind {
 }
 
 pub trait ErrorExt {
+    fn trap(msg: impl Into<String>) -> Self;
     fn too_big() -> Self;
     fn badf() -> Self;
     fn exist() -> Self;
@@ -64,6 +65,9 @@ pub trait ErrorExt {
 }
 
 impl ErrorExt for Error {
+    fn trap(msg: impl Into<String>) -> Self {
+        anyhow::anyhow!(msg.into())
+    }
     fn too_big() -> Self {
         ErrorKind::TooBig.into()
     }