ls: adapt to standardized error handling

src/uu/ls/src/ls.rs

@@ -26,10 +26,11 @@ use quoting_style::{escape_name, QuotingStyle};
 use std::os::windows::fs::MetadataExt;
 use std::{
     cmp::Reverse,
+    error::Error,
+    fmt::Display,
     fs::{self, DirEntry, FileType, Metadata},
     io::{stdout, BufWriter, Stdout, Write},
     path::{Path, PathBuf},
-    process::exit,
     time::{SystemTime, UNIX_EPOCH},
 };
 #[cfg(unix)]
@@ -38,8 +39,8 @@ use std::{
     os::unix::fs::{FileTypeExt, MetadataExt},
     time::Duration,
 };
-
 use term_grid::{Cell, Direction, Filling, Grid, GridOptions};
+use uucore::error::{set_exit_code, FromIo, UCustomError, UResult};
 
 use unicode_width::UnicodeWidthStr;
 #[cfg(unix)]
@@ -125,6 +126,32 @@ pub mod options {
     pub static IGNORE: &str = "ignore";
 }
 
+#[derive(Debug)]
+enum LsError {
+    InvalidLineWidth(String),
+    NoMetadata(PathBuf),
+}
+
+impl UCustomError for LsError {
+    fn code(&self) -> i32 {
+        match self {
+            LsError::InvalidLineWidth(_) => 2,
+            LsError::NoMetadata(_) => 1,
+        }
+    }
+}
+
+impl Error for LsError {}
+
+impl Display for LsError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            LsError::InvalidLineWidth(s) => write!(f, "invalid line width: '{}'", s),
+            LsError::NoMetadata(p) => write!(f, "could not open file: '{}'", p.display()),
+        }
+    }
+}
+
 #[derive(PartialEq, Eq)]
 enum Format {
     Columns,
@@ -218,7 +245,7 @@ struct LongFormat {
 
 impl Config {
     #[allow(clippy::cognitive_complexity)]
-    fn from(options: clap::ArgMatches) -> Config {
+    fn from(options: clap::ArgMatches) -> UResult<Config> {
         let (mut format, opt) = if let Some(format_) = options.value_of(options::FORMAT) {
             (
                 match format_ {
@@ -369,15 +396,13 @@ impl Config {
             }
         };
 
-        let width = options
-            .value_of(options::WIDTH)
-            .map(|x| {
-                x.parse::<u16>().unwrap_or_else(|_e| {
-                    show_error!("invalid line width: '{}'", x);
-                    exit(2);
-                })
-            })
-            .or_else(|| termsize::get().map(|s| s.cols));
+        let width = match options.value_of(options::WIDTH) {
+            Some(x) => match x.parse::<u16>() {
+                Ok(u) => Some(u),
+                Err(_) => return Err(LsError::InvalidLineWidth(x.into()).into()),
+            },
+            None => termsize::get().map(|s| s.cols),
+        };
 
         #[allow(clippy::needless_bool)]
         let show_control = if options.is_present(options::HIDE_CONTROL_CHARS) {
@@ -528,7 +553,7 @@ impl Config {
             Dereference::DirArgs
         };
 
-        Config {
+        Ok(Config {
             format,
             files,
             sort,
@@ -547,11 +572,12 @@ impl Config {
             quoting_style,
             indicator_style,
             time_style,
-        }
+        })
     }
 }
 
-pub fn uumain(args: impl uucore::Args) -> i32 {
+#[uucore_procs::gen_uumain]
+pub fn uumain(args: impl uucore::Args) -> UResult<()> {
     let args = args
         .collect_str(InvalidEncodingHandling::Ignore)
         .accept_any();
@@ -567,7 +593,7 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
         .map(|v| v.map(ToString::to_string).collect())
         .unwrap_or_else(|| vec![String::from(".")]);
 
-    list(locs, Config::from(matches))
+    list(locs, Config::from(matches)?)
 }
 
 pub fn uu_app() -> App<'static, 'static> {
@@ -1190,10 +1216,9 @@ impl PathData {
     }
 }
 
-fn list(locs: Vec<String>, config: Config) -> i32 {
+fn list(locs: Vec<String>, config: Config) -> UResult<()> {
     let mut files = Vec::<PathData>::new();
     let mut dirs = Vec::<PathData>::new();
-    let mut has_failed = false;
 
     let mut out = BufWriter::new(stdout());
 
@@ -1202,19 +1227,16 @@ fn list(locs: Vec<String>, config: Config) -> i32 {
         let path_data = PathData::new(p, None, None, &config, true);
 
         if path_data.md().is_none() {
-            show_error!("'{}': {}", &loc, "No such file or directory");
-            /*
-            We found an error, the return code of ls should not be 0
-            And no need to continue the execution
-            */
-            has_failed = true;
+            show!(std::io::ErrorKind::NotFound
+                .map_err_context(|| format!("cannot access '{}'", path_data.p_buf.display())));
+            // We found an error, no need to continue the execution
             continue;
         }
 
         let show_dir_contents = match path_data.file_type() {
             Some(ft) => !config.directory && ft.is_dir(),
             None => {
-                has_failed = true;
+                set_exit_code(1);
                 false
             }
         };
@@ -1235,11 +1257,8 @@ fn list(locs: Vec<String>, config: Config) -> i32 {
         }
         enter_directory(&dir, &config, &mut out);
     }
-    if has_failed {
-        1
-    } else {
-        0
-    }
+
+    Ok(())
 }
 
 fn sort_entries(entries: &mut Vec<PathData>, config: &Config) {
@@ -1478,7 +1497,7 @@ fn display_item_long(
 ) {
     let md = match item.md() {
         None => {
-            show_error!("could not show file: {}", &item.p_buf.display());
+            show!(LsError::NoMetadata(item.p_buf.clone()));
             return;
         }
         Some(md) => md,