feat: add support for -d

- only list directories by using `-d` flag

src/main.rs

@@ -119,6 +119,7 @@ fn is_executable(metadata: &Metadata) -> bool {
 struct Config {
     use_color: bool,
     show_hidden: bool,
+    show_only_dirs: bool,
     max_level: usize,
     include_glob: Option<GlobMatcher>,
 }
@@ -138,6 +139,7 @@ impl TryFrom<&Args> for Config {
         Ok(Config {
             use_color: value.color_on || !value.color_off,
             show_hidden: value.show_all,
+            show_only_dirs: value.only_dirs,
             max_level: value.max_level,
             include_glob,
         })
@@ -178,6 +180,7 @@ impl<'a> TreePrinter<'a> {
     fn get_iterator(&self, path: &Path) -> filter::FilteredIterator {
         let config = pathiterator::FileIteratorConfig {
             include_glob: self.config.include_glob.clone(),
+            show_only_dirs: self.config.show_only_dirs,
             max_level: self.config.max_level,
             show_hidden: self.config.show_hidden,
         };
@@ -229,6 +232,7 @@ impl<'a> TreePrinter<'a> {
     }
 }
 
+#[allow(clippy::struct_excessive_bools)]
 #[derive(Debug, Parser)]
 struct Args {
     /// Show hidden files
@@ -249,6 +253,9 @@ struct Args {
     /// Descend only <level> directories deep
     #[clap(short = 'L', long = "level", default_value_t = usize::max_value())]
     max_level: usize,
+    /// List directories only
+    #[clap(short = 'd', default_value = "false")]
+    only_dirs: bool,
 }
 
 fn main() -> Result<(), Box<dyn Error>> {
@@ -264,11 +271,15 @@ fn main() -> Result<(), Box<dyn Error>> {
             .map_err(|e| format!("Program failed with error: {e}"))?
     };
 
-    writeln!(
-        &mut term,
-        "\n{} directories, {} files",
-        summary.num_folders, summary.num_files
-    )
+    if args.only_dirs {
+        writeln!(&mut term, "\n{} directories", summary.num_folders)
+    } else {
+        writeln!(
+            &mut term,
+            "\n{} directories, {} files",
+            summary.num_folders, summary.num_files
+        )
+    }
     .map_err(|e| format!("Failed to print summary: {e}"))?;
 
     Ok(())

src/pathiterator.rs

@@ -43,6 +43,7 @@ impl IteratorItem {
 #[derive(Debug)]
 pub struct FileIteratorConfig {
     pub show_hidden: bool,
+    pub show_only_dirs: bool,
     pub max_level: usize,
     pub include_glob: Option<GlobMatcher>,
 }
@@ -57,9 +58,18 @@ fn order_dir_entry(a: &DirEntry, b: &DirEntry) -> Ordering {
     b.file_name().cmp(&a.file_name())
 }
 
-fn get_sorted_dir_entries(path: &Path) -> io::Result<Vec<DirEntry>> {
+fn get_sorted_dir_entries(path: &Path, only_dirs: bool) -> io::Result<Vec<DirEntry>> {
     let entries = fs::read_dir(path)?;
-    let mut dir_entries: Vec<DirEntry> = entries.into_iter().collect::<io::Result<Vec<_>>>()?;
+    let mut dir_entries: Vec<DirEntry> = entries
+        .into_iter()
+        .filter(|entry| {
+            entry.as_ref().is_ok_and(|entry| {
+                entry
+                    .metadata()
+                    .is_ok_and(|meta| !only_dirs || meta.is_dir())
+            })
+        })
+        .collect::<io::Result<Vec<_>>>()?;
     dir_entries.sort_by(order_dir_entry);
     Ok(dir_entries)
 }
@@ -79,29 +89,28 @@ impl FileIterator {
     }
 
     fn is_included(&self, name: &str, is_dir: bool) -> bool {
-        (!name.starts_with('.') && self.config.show_hidden) || is_dir || self.is_glob_included(name)
+        (self.config.show_hidden || !name.starts_with('.'))
+            && (is_dir || self.is_glob_included(name))
     }
 
     fn push_dir(&mut self, item: &IteratorItem) {
-        let entries = get_sorted_dir_entries(&item.path).unwrap_or_else(|_| {
-            panic!(
-                "Couldn't retrieve files in directory: {}",
-                item.path.display()
-            )
-        });
-
-        let mut entries: Vec<IteratorItem> = entries
-            .iter()
-            .map(|e| IteratorItem::new(&e.path(), item.level + 1, false))
-            .filter(|item| self.is_included(&item.file_name, item.is_dir()))
-            .collect();
-
-        if let Some(item) = entries.first_mut() {
-            item.is_last = true;
+        let entries = get_sorted_dir_entries(&item.path, self.config.show_only_dirs)
+            .unwrap_or_else(|_| {
+                panic!(
+                    "Couldn't retrieve files in directory: {}",
+                    item.path.display()
+                )
+            });
+
+        for entry in entries {
+            let item = IteratorItem::new(&entry.path(), item.level + 1, false);
+            if self.is_included(&item.file_name, item.is_dir()) {
+                self.queue.push_back(item);
+            }
         }
 
-        for item in entries {
-            self.queue.push_back(item);
+        if let Some(item) = self.queue.back_mut() {
+            item.is_last = true;
         }
     }
 }