Implement Total size feature (#2170)

* ls: Implement total size feature

- Implement total size reporting that was missing
- Fix minor formatting / readability nits

* tests: Add tests for ls total sizes feature

* ls: Fix MSRV build errors due to unsupported attributes for if blocks

* ls: Add windows support for total sizes feature

- Add windows support (defaults to file size as block sizes related
infromation is not avialable on windows)
- Renamed some functions

tests/by-util/test_ls.rs

@@ -5,6 +5,7 @@ use crate::common::util::*;
 extern crate regex;
 use self::regex::Regex;
 
+use std::collections::HashMap;
 use std::path::Path;
 use std::thread::sleep;
 use std::time::Duration;
@@ -308,6 +309,50 @@ fn test_ls_long() {
     }
 }
 
+#[test]
+fn test_ls_long_total_size() {
+    let scene = TestScenario::new(util_name!());
+    let at = &scene.fixtures;
+    at.touch(&at.plus_as_string("test-long"));
+    at.append("test-long", "1");
+    at.touch(&at.plus_as_string("test-long2"));
+    at.append("test-long2", "2");
+
+    let expected_prints: HashMap<_, _> = if cfg!(unix) {
+        [
+            ("long_vanilla", "total 8"),
+            ("long_human_readable", "total 8.0K"),
+            ("long_si", "total 8.2k"),
+        ]
+        .iter()
+        .cloned()
+        .collect()
+    } else {
+        [
+            ("long_vanilla", "total 2"),
+            ("long_human_readable", "total 2"),
+            ("long_si", "total 2"),
+        ]
+        .iter()
+        .cloned()
+        .collect()
+    };
+
+    for arg in &["-l", "--long", "--format=long", "--format=verbose"] {
+        let result = scene.ucmd().arg(arg).succeeds();
+        result.stdout_contains(expected_prints["long_vanilla"]);
+
+        for arg2 in &["-h", "--human-readable", "--si"] {
+            let result = scene.ucmd().arg(arg).arg(arg2).succeeds();
+            result.stdout_contains(if *arg2 == "--si" {
+                expected_prints["long_si"]
+            } else {
+                expected_prints["long_human_readable"]
+            });
+        }
+    }
+}
+
 #[test]
 fn test_ls_long_formats() {
     let scene = TestScenario::new(util_name!());