From ab4036297b16855ce51c3302a5ddaa390a83d163 Mon Sep 17 00:00:00 2001
From: Jeffrey Finkelstein <jeffrey.finkelstein@protonmail.com>
Date: Sun, 16 Jan 2022 13:47:18 -0500
Subject: [PATCH] head: use uucore error handling instead of custom

Use `show!()` and `USimpleError` to handle I/O errors instead of using
custom code.
---
 src/uu/head/src/head.rs | 39 +++++++++++++++------------------------
 1 file changed, 15 insertions(+), 24 deletions(-)

diff --git a/src/uu/head/src/head.rs b/src/uu/head/src/head.rs
index e3325d084..3f6c8dfab 100644
--- a/src/uu/head/src/head.rs
+++ b/src/uu/head/src/head.rs
@@ -10,8 +10,8 @@ use std::convert::TryFrom;
 use std::ffi::OsString;
 use std::io::{self, BufWriter, ErrorKind, Read, Seek, SeekFrom, Write};
 use uucore::display::Quotable;
-use uucore::error::{UResult, USimpleError};
-use uucore::show_error_custom_description;
+use uucore::error::{FromIo, UError, UResult, USimpleError};
+use uucore::show;
 
 const BUF_SIZE: usize = 65536;
 
@@ -367,7 +367,6 @@ fn head_file(input: &mut std::fs::File, options: &HeadOptions) -> std::io::Resul
 }
 
 fn uu_head(options: &HeadOptions) -> UResult<()> {
-    let mut error_count = 0;
     let mut first = true;
     for file in &options.files {
         let res = match file.as_str() {
@@ -401,19 +400,10 @@ fn uu_head(options: &HeadOptions) -> UResult<()> {
                 let mut file = match std::fs::File::open(name) {
                     Ok(f) => f,
                     Err(err) => {
-                        let prefix = format!("cannot open {} for reading", name.quote());
-                        match err.kind() {
-                            ErrorKind::NotFound => {
-                                show_error_custom_description!(prefix, "No such file or directory");
-                            }
-                            ErrorKind::PermissionDenied => {
-                                show_error_custom_description!(prefix, "Permission denied");
-                            }
-                            _ => {
-                                show_error_custom_description!(prefix, "{}", err);
-                            }
-                        }
-                        error_count += 1;
+                        show!(err.map_err_context(|| format!(
+                            "cannot open {} for reading",
+                            name.quote()
+                        )));
                         continue;
                     }
                 };
@@ -432,17 +422,18 @@ fn uu_head(options: &HeadOptions) -> UResult<()> {
             } else {
                 file
             };
-            let prefix = format!("error reading {}", name);
-            show_error_custom_description!(prefix, "Input/output error");
-            error_count += 1;
+            show!(USimpleError::new(
+                1,
+                format!("error reading {}: Input/output error", name)
+            ));
         }
         first = false;
     }
-    if error_count > 0 {
-        Err(USimpleError::new(1, ""))
-    } else {
-        Ok(())
-    }
+    // Even though this is returning `Ok`, it is possible that a call
+    // to `show!()` and thus a call to `set_exit_code()` has been
+    // called above. If that happens, then this process will exit with
+    // a non-zero exit code.
+    Ok(())
 }
 
 #[uucore_procs::gen_uumain]