Support completion for paths with multiple dots (#1640)

* refactor: expand_path and expand_ndots now work for any string.

* refactor: refactor test and add new ones.

* refactor: convert expanded to owned string

* feat: pub export of expand_ndots

* feat: add completion for ndots in fs-shell

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

@@ -11,6 +11,7 @@ use crate::shell::completer::NuCompleter;
 use crate::shell::shell::Shell;
 use crate::utils::FileStructure;
 use nu_errors::ShellError;
+use nu_parser::expand_ndots;
 use nu_protocol::{Primitive, ReturnSuccess, UntaggedValue};
 use rustyline::completion::FilenameCompleter;
 use rustyline::hint::{Hinter, HistoryHinter};
@@ -994,7 +995,27 @@ impl Shell for FilesystemShell {
         pos: usize,
         ctx: &rustyline::Context<'_>,
     ) -> Result<(usize, Vec<rustyline::completion::Pair>), rustyline::error::ReadlineError> {
-        self.completer.complete(line, pos, ctx)
+        let expanded = expand_ndots(&line);
+
+        // Find the first not-matching char position, if there is one
+        let differ_pos = line
+            .chars()
+            .zip(expanded.chars())
+            .enumerate()
+            .find(|(_index, (a, b))| a != b)
+            .map(|(differ_pos, _)| differ_pos);
+
+        let pos = if let Some(differ_pos) = differ_pos {
+            if differ_pos < pos {
+                pos + (expanded.len() - line.len())
+            } else {
+                pos
+            }
+        } else {
+            pos
+        };
+
+        self.completer.complete(&expanded, pos, ctx)
     }
 
     fn hint(&self, line: &str, pos: usize, ctx: &rustyline::Context<'_>) -> Option<String> {

crates/nu-parser/src/lib.rs

@@ -8,5 +8,6 @@ mod signature;
 pub use crate::files::Files;
 pub use crate::lite_parse::{lite_parse, LiteBlock};
 pub use crate::parse::{classify_block, garbage};
+pub use crate::path::expand_ndots;
 pub use crate::shapes::shapes;
 pub use crate::signature::{Signature, SignatureRegistry};

crates/nu-parser/src/parse.rs

@@ -366,7 +366,7 @@ fn parse_arg(
         }
         SyntaxShape::Pattern => {
             let trimmed = trim_quotes(&lite_arg.item);
-            let expanded = expand_path(&trimmed);
+            let expanded = expand_path(&trimmed).to_string();
             (
                 SpannedExpression::new(Expression::pattern(expanded), lite_arg.span),
                 None,
@@ -378,7 +378,7 @@ fn parse_arg(
         SyntaxShape::Unit => parse_unit(&lite_arg),
         SyntaxShape::Path => {
             let trimmed = trim_quotes(&lite_arg.item);
-            let expanded = expand_path(&trimmed);
+            let expanded = expand_path(&trimmed).to_string();
             let path = Path::new(&expanded);
             (
                 SpannedExpression::new(Expression::FilePath(path.to_path_buf()), lite_arg.span),
@@ -1068,7 +1068,7 @@ fn classify_pipeline(
         } else {
             let name = lite_cmd.name.clone().map(|v| {
                 let trimmed = trim_quotes(&v);
-                expand_path(&trimmed)
+                expand_path(&trimmed).to_string()
             });
 
             let mut args = vec![];

crates/nu-parser/src/path.rs

@@ -1,35 +1,69 @@
-use std::path::{Component, Path, PathBuf};
+use std::borrow::Cow;
 
-fn expand_ndots(path: &str) -> String {
-    let path = Path::new(path);
-    let mut expanded = PathBuf::new();
-
-    for component in path.components() {
-        match component {
-            Component::Normal(normal) => {
-                if let Some(normal) = normal.to_str() {
-                    if normal.chars().all(|c| c == '.') {
-                        for _ in 0..(normal.len() - 1) {
-                            expanded.push("..");
+fn handle_dots_push(string: &mut String, count: u8) {
+    if count < 1 {
+        return;
     }
+
+    if count == 1 {
+        string.push('.');
+        return;
+    }
+
+    for _ in 0..(count - 1) {
+        string.push_str("../");
+    }
+
+    string.pop(); // remove last '/'
+}
+
+pub fn expand_ndots(path: &str) -> Cow<'_, str> {
+    let mut dots_count = 0u8;
+    let ndots_present = {
+        for chr in path.chars() {
+            if chr == '.' {
+                dots_count += 1;
             } else {
-                        expanded.push(normal);
+                if dots_count > 2 {
+                    break;
                 }
+
+                dots_count = 0;
+            }
+        }
+
+        dots_count > 2
+    };
+
+    if !ndots_present {
+        return path.into();
+    }
+
+    let mut dots_count = 0u8;
+    let mut expanded = String::new();
+    for chr in path.chars() {
+        if chr != '.' {
+            handle_dots_push(&mut expanded, dots_count);
+            dots_count = 0;
+            expanded.push(chr);
         } else {
-                    expanded.push(normal);
+            dots_count += 1;
         }
     }
 
-            c => expanded.push(c.as_os_str()),
-        }
+    handle_dots_push(&mut expanded, dots_count);
+
+    expanded.into()
 }
 
-    expanded.to_string_lossy().to_string()
-}
+pub fn expand_path<'a>(path: &'a str) -> Cow<'a, str> {
+    let tilde_expansion: Cow<'a, str> = shellexpand::tilde(path);
+    let ndots_expansion: Cow<'a, str> = match tilde_expansion {
+        Cow::Borrowed(b) => expand_ndots(b),
+        Cow::Owned(o) => expand_ndots(&o).to_string().into(),
+    };
 
-pub fn expand_path(path: &str) -> String {
-    let tilde_expansion = shellexpand::tilde(path);
-    expand_ndots(&tilde_expansion)
+    ndots_expansion
 }
 
 #[cfg(test)]
@@ -37,16 +71,25 @@ mod tests {
     use super::*;
 
     #[test]
-    fn expand_in_relative_path() {
-        let expected = Path::new("../..");
-        let expanded = PathBuf::from(expand_path("..."));
-        assert_eq!(expected, &expanded);
+    fn string_without_ndots() {
+        assert_eq!("../hola", &expand_ndots("../hola").to_string());
     }
 
     #[test]
-    fn expand_in_absolute_path() {
-        let expected = Path::new("/foo/../..");
-        let expanded = PathBuf::from(expand_path("/foo/..."));
-        assert_eq!(expected, &expanded);
+    fn string_with_three_ndots() {
+        assert_eq!("../..", &expand_ndots("...").to_string());
+    }
+
+    #[test]
+    fn string_with_three_ndots_and_final_slash() {
+        assert_eq!("../../", &expand_ndots(".../").to_string());
+    }
+
+    #[test]
+    fn string_with_three_ndots_and_garbage() {
+        assert_eq!(
+            "ls ../../ garbage.*[",
+            &expand_ndots("ls .../ garbage.*[").to_string(),
+        );
     }
 }