melib: add complete() method to ShellExpandTrait

complete(force: bool) returns String path segments that when appended to
the path will form a valid location. Example:

  - User types: save-attachment 1 /t
  - User presses <TAB>.
  - complete() returns the suggestion: "mp/"
  - User sees: save-attachment 1 /tmp/

complete() uses openat() and getdents64 syscalls hoping it's faster than
using stdlib.

1 files changed, 13 insertions, 0 deletions

diff --git a/ui/src/components/utilities.rs b/ui/src/components/utilities.rs
index c8ea24a7..3a79be93 100644
--- a/ui/src/components/utilities.rs
+++ b/ui/src/components/utilities.rs
@@ -897,6 +897,19 @@ impl Component for StatusBar {
                         None
                     }
                 }));
+                if let Some(p) = self
+                    .ex_buffer
+                    .as_str()
+                    .split_whitespace()
+                    .last()
+                    .map(std::path::Path::new)
+                {
+                    suggestions.extend(
+                        debug!(debug!(p).complete(true))
+                            .into_iter()
+                            .map(|m| format!("{}{}", self.ex_buffer.as_str(), m).into()),
+                    );
+                }
                 if suggestions.is_empty() && !self.auto_complete.suggestions().is_empty() {
                     self.auto_complete.set_suggestions(suggestions);
                     /* redraw self.container because we have got ridden of an autocomplete