basename: move from getopts to clap (#2117)

Use clap for argument parsing instead of getopts
Also, make the following changes

* Use `executable!()` macro to output the name of utility

* Add another usage to help message

src/uu/basename/Cargo.toml

@@ -15,6 +15,7 @@ edition = "2018"
 path = "src/basename.rs"
 
 [dependencies]
+clap = "2.33.2"
 uucore = { version=">=0.0.8", package="uucore", path="../../uucore" }
 uucore_procs = { version=">=0.0.5", package="uucore_procs", path="../../uucore_procs" }
 

src/uu/basename/src/basename.rs

@@ -10,80 +10,103 @@
 #[macro_use]
 extern crate uucore;
 
+use clap::{App, Arg};
 use std::path::{is_separator, PathBuf};
 use uucore::InvalidEncodingHandling;
 
-static NAME: &str = "basename";
-static SYNTAX: &str = "NAME [SUFFIX]";
+static VERSION: &str = env!("CARGO_PKG_VERSION");
 static SUMMARY: &str = "Print NAME with any leading directory components removed
 If specified, also remove a trailing SUFFIX";
-static LONG_HELP: &str = "";
+
+fn get_usage() -> String {
+    format!(
+        "{0} NAME [SUFFIX]
+    {0} OPTION... NAME...",
+        executable!()
+    )
+}
+
+pub mod options {
+    pub static MULTIPLE: &str = "multiple";
+    pub static NAME: &str = "name";
+    pub static SUFFIX: &str = "suffix";
+    pub static ZERO: &str = "zero";
+}
 
 pub fn uumain(args: impl uucore::Args) -> i32 {
     let args = args
         .collect_str(InvalidEncodingHandling::ConvertLossy)
         .accept_any();
+    let usage = get_usage();
     //
     // Argument parsing
     //
-    let matches = app!(SYNTAX, SUMMARY, LONG_HELP)
-        .optflag(
-            "a",
-            "multiple",
-            "Support more than one argument. Treat every argument as a name.",
+    let matches = App::new(executable!())
+        .version(VERSION)
+        .about(SUMMARY)
+        .usage(&usage[..])
+        .arg(
+            Arg::with_name(options::MULTIPLE)
+                .short("a")
+                .long(options::MULTIPLE)
+                .help("support multiple arguments and treat each as a NAME"),
         )
-        .optopt(
-            "s",
-            "suffix",
-            "Remove a trailing suffix. This option implies the -a option.",
-            "SUFFIX",
+        .arg(Arg::with_name(options::NAME).multiple(true).hidden(true))
+        .arg(
+            Arg::with_name(options::SUFFIX)
+                .short("s")
+                .long(options::SUFFIX)
+                .value_name("SUFFIX")
+                .help("remove a trailing SUFFIX; implies -a"),
         )
-        .optflag(
-            "z",
-            "zero",
-            "Output a zero byte (ASCII NUL) at the end of each line, rather than a newline.",
+        .arg(
+            Arg::with_name(options::ZERO)
+                .short("z")
+                .long(options::ZERO)
+                .help("end each output line with NUL, not newline"),
         )
-        .parse(args);
+        .get_matches_from(args);
 
     // too few arguments
-    if matches.free.is_empty() {
+    if !matches.is_present(options::NAME) {
         crash!(
             1,
             "{0}: {1}\nTry '{0} --help' for more information.",
-            NAME,
+            executable!(),
             "missing operand"
         );
     }
-    let opt_s = matches.opt_present("s");
-    let opt_a = matches.opt_present("a");
-    let opt_z = matches.opt_present("z");
+
+    let opt_s = matches.is_present(options::SUFFIX);
+    let opt_a = matches.is_present(options::MULTIPLE);
+    let opt_z = matches.is_present(options::ZERO);
     let multiple_paths = opt_s || opt_a;
     // too many arguments
-    if !multiple_paths && matches.free.len() > 2 {
+    if !multiple_paths && matches.occurrences_of(options::NAME) > 2 {
         crash!(
             1,
             "{0}: extra operand '{1}'\nTry '{0} --help' for more information.",
-            NAME,
-            matches.free[2]
+            executable!(),
+            matches.values_of(options::NAME).unwrap().nth(2).unwrap()
         );
     }
 
     let suffix = if opt_s {
-        matches.opt_str("s").unwrap()
-    } else if !opt_a && matches.free.len() > 1 {
-        matches.free[1].clone()
+        matches.value_of(options::SUFFIX).unwrap()
+    } else if !opt_a && matches.occurrences_of(options::NAME) > 1 {
+        matches.values_of(options::NAME).unwrap().nth(1).unwrap()
     } else {
-        "".to_owned()
+        ""
     };
 
     //
     // Main Program Processing
     //
 
-    let paths = if multiple_paths {
-        &matches.free[..]
+    let paths: Vec<_> = if multiple_paths {
+        matches.values_of(options::NAME).unwrap().collect()
     } else {
-        &matches.free[0..1]
+        matches.values_of(options::NAME).unwrap().take(1).collect()
     };
 
     let line_ending = if opt_z { "\0" } else { "\n" };