Added new flag '--all/-a' for Ls, also refactor some code (#1483)

* Utility function to detect hidden folders.
Implemented for Unix and Windows.

* Rename function argument.

* Revert "Rename function argument."

This reverts commit e7ab70f0f0.

* Add flag '--all/-a' to Ls

* Rename function argument.

* Check if flag '--all/-a' is present and path is hidden.
Replace match with map_err for glob result.
Remove redundancy in stream body.
Included comments on new stream body.
Replace async_stream::stream with async_stream::try_stream.
Minor tweaks to is_empty_dir.
Fix and refactor is_hidden_dir.

* Fix "implicit" bool coerse

* Fixed clippy errors

crates/nu-cli/src/commands/ls.rs

@@ -10,6 +10,7 @@ pub struct Ls;
 #[derive(Deserialize)]
 pub struct LsArgs {
     pub path: Option<Tagged<PathBuf>>,
+    pub all: bool,
     pub full: bool,
     #[serde(rename = "short-names")]
     pub short_names: bool,
@@ -29,6 +30,7 @@ impl PerItemCommand for Ls {
                 SyntaxShape::Pattern,
                 "a path to get the directory contents from",
             )
+            .switch("all", "also show hidden files", Some('a'))
             .switch(
                 "full",
                 "list all available columns for each entry",

crates/nu-cli/src/data/files.rs

@@ -36,13 +36,13 @@ pub(crate) fn dir_entry_dict(
     metadata: Option<&std::fs::Metadata>,
     tag: impl Into<Tag>,
     full: bool,
-    name_only: bool,
+    short_name: bool,
     with_symlink_targets: bool,
 ) -> Result<Value, ShellError> {
     let tag = tag.into();
     let mut dict = TaggedDictBuilder::new(&tag);
 
-    let name = if name_only {
+    let name = if short_name {
         filename.file_name().and_then(|s| s.to_str())
     } else {
         filename.to_str()

crates/nu-cli/src/shell/filesystem_shell.rs

@@ -14,7 +14,7 @@ use nu_parser::ExpandContext;
 use nu_protocol::{Primitive, ReturnSuccess, UntaggedValue};
 use rustyline::completion::FilenameCompleter;
 use rustyline::hint::{Hinter, HistoryHinter};
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 use std::sync::atomic::Ordering;
 use trash as SendToTrash;
 
@@ -93,6 +93,7 @@ impl Shell for FilesystemShell {
         &self,
         LsArgs {
             path,
+            all,
             full,
             short_names,
             with_symlink_targets,
@@ -107,7 +108,7 @@ impl Shell for FilesystemShell {
                 let p_tag = p.tag;
                 let mut p = p.item;
                 if p.is_dir() {
-                    if is_dir_empty(&p) {
+                    if is_empty_dir(&p) {
                         return Ok(OutputStream::empty());
                     }
                     p.push("*");
@@ -115,7 +116,7 @@ impl Shell for FilesystemShell {
                 (p, p_tag)
             }
             None => {
-                if is_dir_empty(&self.path().into()) {
+                if is_empty_dir(&self.path()) {
                     return Ok(OutputStream::empty());
                 } else {
                     (PathBuf::from("./*"), context.name.clone())
@@ -123,11 +124,9 @@ impl Shell for FilesystemShell {
             }
         };
 
-        let mut paths = match glob::glob(&path.to_string_lossy()) {
-            Ok(g) => Ok(g),
-            Err(e) => Err(ShellError::labeled_error("Glob error", e.msg, &p_tag)),
-        }?
-        .peekable();
+        let mut paths = glob::glob(&path.to_string_lossy())
+            .map_err(|e| ShellError::labeled_error("Glob error", e.to_string(), &p_tag))?
+            .peekable();
 
         if paths.peek().is_none() {
             return Err(ShellError::labeled_error(
@@ -137,35 +136,53 @@ impl Shell for FilesystemShell {
             ));
         }
 
-        let stream = async_stream! {
+        // Generated stream: impl Stream<Item = Result<ReturnSuccess, ShellError>
+        let stream = async_stream::try_stream! {
             for path in paths {
+                // Handle CTRL+C presence
                 if ctrl_c.load(Ordering::SeqCst) {
                     break;
                 }
-                match path {
-                    Ok(p) => match std::fs::symlink_metadata(&p) {
-                        Ok(m) => {
-                            match dir_entry_dict(&p, Some(&m), name_tag.clone(), full, short_names, with_symlink_targets) {
-                                Ok(d) => yield ReturnSuccess::value(d),
-                                Err(e) => yield Err(e)
-                            }
-                        }
-                        Err(e) => {
-                            match e.kind() {
-                                PermissionDenied => {
-                                    match dir_entry_dict(&p, None, name_tag.clone(), full, short_names, with_symlink_targets) {
-                                        Ok(d) => yield ReturnSuccess::value(d),
-                                        Err(e) => yield Err(e)
-                                    }
-                                },
-                                _ => yield Err(ShellError::from(e))
-                            }
-                        }
-                    }
-                    Err(e) => yield Err(e.into_error().into()),
+
+                // Map GlobError to ShellError and gracefully try to unwrap the path
+                let path = path.map_err(|e| ShellError::from(e.into_error()))?;
+
+                // Skip if '--all/-a' flag is present and this path is hidden
+                if !all && is_hidden_dir(&path) {
+                    continue;
                 }
+
+                // Get metadata from current path, if we don't have enough
+                // permissions to stat on file don't use any metadata, otherwise
+                // return the error and gracefully unwrap metadata (which yields
+                // Option<Metadata>)
+                let metadata = match std::fs::symlink_metadata(&path) {
+                    Ok(metadata) => Ok(Some(metadata)),
+                    Err(e) => if let PermissionDenied = e.kind() {
+                        Ok(None)
+                    } else {
+                        Err(e)
+                    },
+                }?;
+
+                // Build dict entry for this path and possibly using some metadata.
+                // Map the possible dict entry into a Value, gracefully unwrap it
+                // with '?'
+                let entry = dir_entry_dict(
+                    &path,
+                    metadata.as_ref(),
+                    name_tag.clone(),
+                    full,
+                    short_names,
+                    with_symlink_targets
+                )
+                .map(|entry| ReturnSuccess::Value(entry.into()))?;
+
+                // Finally yield the generated entry that was mapped to Value
+                yield entry;
             }
         };
+
         Ok(stream.to_output_stream())
     }
 
@@ -1129,9 +1146,30 @@ impl Shell for FilesystemShell {
     }
 }
 
-fn is_dir_empty(d: &PathBuf) -> bool {
-    match d.read_dir() {
-        Err(_e) => true,
+fn is_empty_dir(dir: impl AsRef<Path>) -> bool {
+    match dir.as_ref().read_dir() {
+        Err(_) => true,
         Ok(mut s) => s.next().is_none(),
     }
 }
+
+fn is_hidden_dir(dir: impl AsRef<Path>) -> bool {
+    cfg_if::cfg_if! {
+        if #[cfg(windows)] {
+            use std::os::windows::fs::MetadataExt;
+
+            if let Ok(metadata) = dir.as_ref().metadata() {
+                let attributes = metadata.file_attributes();
+                // https://docs.microsoft.com/en-us/windows/win32/fileio/file-attribute-constants
+                (attributes & 0x2) != 0
+            } else {
+                false
+            }
+        } else {
+            dir.as_ref()
+                .file_name()
+                .map(|name| name.to_string_lossy().starts_with('.'))
+                .unwrap_or(false)
+        }
+    }
+}

crates/nu-cli/src/shell/help_shell.rs

@@ -162,7 +162,7 @@ impl Shell for HelpShell {
                     cwd.pop();
                 } else {
                     match target.to_str() {
-                        Some(target) => match target.chars().nth(0) {
+                        Some(target) => match target.chars().next() {
                             Some(x) if x == '/' => cwd = PathBuf::from(target),
                             _ => cwd.push(target),
                         },

crates/nu-cli/src/shell/value_shell.rs

@@ -144,7 +144,7 @@ impl Shell for ValueShell {
                     cwd = PathBuf::from(&self.last_path);
                 } else {
                     match target.to_str() {
-                        Some(target) => match target.chars().nth(0) {
+                        Some(target) => match target.chars().next() {
                             Some(x) if x == '/' => cwd = PathBuf::from(target),
                             _ => cwd.push(target),
                         },

crates/nu-parser/src/hir/syntax_shape.rs

@@ -137,7 +137,7 @@ pub struct ExpandContext<'context> {
 
 impl<'context> ExpandContext<'context> {
     pub(crate) fn homedir(&self) -> Option<&Path> {
-        self.homedir.as_ref().map(|h| h.as_path())
+        self.homedir.as_deref()
     }
 
     pub(crate) fn source(&self) -> &'context Text {

crates/nu-parser/src/parse/parser.rs

@@ -372,7 +372,7 @@ fn word<'a, T, U, V>(
         let (input, _) = start_predicate(input)?;
         let (input, _) = many0(next_predicate)(input)?;
 
-        let next_char = &input.fragment.chars().nth(0);
+        let next_char = &input.fragment.chars().next();
 
         match next_char {
             Some('.') => {}
@@ -609,7 +609,7 @@ fn tight<'a>(
 
         let (input, tail) = opt(alt((many1(range_continuation), many1(dot_member))))(input)?;
 
-        let next_char = &input.fragment.chars().nth(0);
+        let next_char = &input.fragment.chars().next();
 
         if is_boundary(*next_char) {
             if let Some(tail) = tail {