Add size option (-s) to the ls command (#1102)

* Lists the size in bytes of each file when `ls -s` is invoked
* Prints '--' to indicate directory sizes are not calculated yet

Co-authored-by: Nathan Hsiao <nnh12@DESKTOP-EQ10QSJ>

applications/ls/src/lib.rs

@@ -19,6 +19,7 @@ use path::Path;
 pub fn main(args: Vec<String>) -> isize {
     let mut opts = Options::new();
     opts.optflag("h", "help", "print this help menu");
+    opts.optflag("s", "size", "print the size of each file in directory");
 
     let matches = match opts.parse(args) {
         Ok(m) => m,
@@ -34,13 +35,16 @@ pub fn main(args: Vec<String>) -> isize {
         return 0;
     }
 
+    let size_option = matches.opt_present("s");
+
     let Ok(curr_wd) = task::with_current_task(|t| t.get_env().lock().working_dir.clone()) else {
         println!("failed to get current task");
         return -1;
     };
+
     // print children of working directory if no child is specified
     if matches.free.is_empty() {
-        print_children(&curr_wd);
+        print_children(&curr_wd, size_option);
         return 0;
     }
 
@@ -49,7 +53,7 @@ pub fn main(args: Vec<String>) -> isize {
     // Navigate to the path specified by first argument
     match path.get(&curr_wd) {
         Some(FileOrDir::Dir(dir)) => {
-            print_children(&dir);
+            print_children(&dir, size_option);
             0
         }
         Some(FileOrDir::File(file)) => {
@@ -63,12 +67,25 @@ pub fn main(args: Vec<String>) -> isize {
     }
 }
 
-fn print_children(dir: &DirRef) {
+fn print_children(dir: &DirRef, print_size: bool) {
     let mut child_string = String::new();
     let mut child_list = dir.lock().list(); 
     child_list.reverse();
     for child in child_list.iter() {
-        writeln!(child_string, "{child}").expect("Failed to write child_string");
+        let child_path = dir.lock().get(child).expect("Failed to get child path");
+        if print_size {
+            match &child_path {
+                FileOrDir::File(file_ref) => {
+                    let file = file_ref.lock();
+                    writeln!(child_string, "   {}    {}", file.len(), child).expect("Failed to write child_string");
+                },
+                FileOrDir::Dir(_) => {
+                    writeln!(child_string, "   --    {}", child).expect("Failed to write child_string");
+                },
+            };
+        } else {
+            writeln!(child_string, "{}", child).expect("Failed to write child_string");
+        }
     }
     println!("{}", child_string);
 }
@@ -80,4 +97,4 @@ fn print_usage(opts: Options) {
 
 const USAGE: &str = "Usage: ls [DIR | FILE]
 List the contents of the given directory or info about the given file.
-If no arguments are provided, it lists the contents of the current directory.";
+If no arguments are provided, it lists the contents of the current directory.";

kernel/fs_node/src/lib.rs

@@ -24,7 +24,6 @@ use alloc::sync::{Arc, Weak};
 use memory::MappedPages;
 use io::{ByteReader, ByteWriter, KnownLength};
 
-
 /// A reference to any type that implements the [`File`] trait,
 /// which can only represent a File (not a Directory).
 pub type FileRef = Arc<Mutex<dyn File + Send>>;