From 0aaf9dca93c7a0edb1bdbadb9be373750466420d Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Mon, 3 May 2021 13:25:55 +0100
Subject: [PATCH] utils: Provide and use <T as Seek>::rewind()

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---
 src/bin/otter.rs | 2 +-
 src/prelude.rs   | 1 -
 src/spec.rs      | 2 +-
 src/utils.rs     | 6 ++++++
 4 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/bin/otter.rs b/src/bin/otter.rs
index c757e1c4..1c663db7 100644
--- a/src/bin/otter.rs
+++ b/src/bin/otter.rs
@@ -1347,7 +1347,7 @@ mod upload_bundle {
       dw.finish().0
     };
     let kind = bundles::Kind::only();
-    f.seek(io::SeekFrom::Start(0)).context("rewind bundle file")?;
+    f.rewind().context("rewind bundle file")?;
     let cmd = MC::UploadBundle {
       game: instance_name.clone(),
       hash: bundles::Hash(hash.into()), kind,
diff --git a/src/prelude.rs b/src/prelude.rs
index 70847be9..223f6c88 100644
--- a/src/prelude.rs
+++ b/src/prelude.rs
@@ -29,7 +29,6 @@ pub use std::hash::Hash;
 pub use std::io;
 pub use std::io::ErrorKind;
 pub use std::io::{BufRead, BufReader, BufWriter, Read, Write};
-pub use std::io::{Seek, SeekFrom};
 pub use std::iter;
 pub use std::iter::repeat_with;
 pub use std::marker::PhantomData;
diff --git a/src/spec.rs b/src/spec.rs
index be423347..8b707c21 100644
--- a/src/spec.rs
+++ b/src/spec.rs
@@ -540,7 +540,7 @@ pub mod imp {
         let mut messagefile = tempfile::tempfile().context("tempfile")?;
         messagefile.write_all(message.as_bytes()).context("write")?;
         messagefile.flush().context("flush")?;
-        messagefile.seek(SeekFrom::Start(0)).context("seek")?;
+        messagefile.rewind().context("seek")?;
         Ok::<_,AE>(messagefile)
       })().context("write email to temporary file.")?;
 
diff --git a/src/utils.rs b/src/utils.rs
index 3c2a20d8..204a3679 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -607,3 +607,9 @@ fn test_digest_write() {
   assert_eq!( got, exp );
   assert_eq!( &obuffer, b"xyz\0" );
 }
+
+#[ext(pub, name=SeekExt)]
+impl<T: io::Seek> T {
+  #[throws(io::Error)]
+  fn rewind(&mut self) { self.seek(io::SeekFrom::Start(0))? }
+}
-- 
2.30.2