Merge pull request #156 from ouch-org/cur-dir-cow

Avoid allocating in `nice_directory_display` when possible, make `Extension` non-exhaustive

src/extension.rs

@@ -6,6 +6,7 @@ use self::CompressionFormat::*;
 
 /// A wrapper around `CompressionFormat` that allows combinations like `tgz`
 #[derive(Debug, Clone, PartialEq, Eq)]
+#[non_exhaustive]
 pub struct Extension {
     /// One extension like "tgz" can be made of multiple CompressionFormats ([Tar, Gz])
     pub compression_formats: &'static [CompressionFormat],
@@ -35,7 +36,7 @@ impl Extension {
 
 impl fmt::Display for Extension {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.write_str(&self.display_text)
+        self.display_text.fmt(f)
     }
 }
 

src/utils.rs

@@ -1,6 +1,7 @@
 //! Random stuff used on ouch.
 
 use std::{
+    borrow::Cow,
     cmp, env,
     ffi::OsStr,
     io,
@@ -109,12 +110,12 @@ pub fn concatenate_list_of_os_str(os_strs: &[impl AsRef<OsStr>]) -> String {
 }
 
 /// Display the directory name, but change to "current directory" when necessary.
-pub fn nice_directory_display(os_str: impl AsRef<OsStr>) -> String {
-    let text = to_utf(os_str);
-    if text == "." {
-        "current directory".to_string()
+pub fn nice_directory_display(os_str: impl AsRef<OsStr>) -> Cow<'static, str> {
+    if os_str.as_ref() == "." {
+        Cow::Borrowed("current directory")
     } else {
-        format!("'{}'", text)
+        let text = to_utf(os_str);
+        Cow::Owned(format!("'{}'", text))
     }
 }