From 625c3f2330739e90b107a32fe3fe51e4c2d2a4b3 Mon Sep 17 00:00:00 2001
From: James Robson <jaggededgedjustice@gmail.com>
Date: Sun, 29 Aug 2021 15:08:45 +0100
Subject: [PATCH] Add -e/-m to realpath

---
 src/uu/realpath/src/realpath.rs | 39 +++++++++++++++++++++++++++---
 tests/by-util/test_realpath.rs  | 43 +++++++++++++++++++++++++++++++++
 2 files changed, 79 insertions(+), 3 deletions(-)

diff --git a/src/uu/realpath/src/realpath.rs b/src/uu/realpath/src/realpath.rs
index cbe1d40da..451253d50 100644
--- a/src/uu/realpath/src/realpath.rs
+++ b/src/uu/realpath/src/realpath.rs
@@ -21,6 +21,8 @@ static OPT_STRIP: &str = "strip";
 static OPT_ZERO: &str = "zero";
 static OPT_PHYSICAL: &str = "physical";
 static OPT_LOGICAL: &str = "logical";
+const OPT_CANONICALIZE_MISSING: &str = "canonicalize-missing";
+const OPT_CANONICALIZE_EXISTING: &str = "canonicalize-existing";
 
 static ARG_FILES: &str = "files";
 
@@ -45,9 +47,16 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
     let zero = matches.is_present(OPT_ZERO);
     let quiet = matches.is_present(OPT_QUIET);
     let logical = matches.is_present(OPT_LOGICAL);
+    let can_mode = if matches.is_present(OPT_CANONICALIZE_EXISTING) {
+        MissingHandling::Existing
+    } else if matches.is_present(OPT_CANONICALIZE_MISSING) {
+        MissingHandling::Missing
+    } else {
+        MissingHandling::Normal
+    };
     let mut retcode = 0;
     for path in &paths {
-        if let Err(e) = resolve_path(path, strip, zero, logical) {
+        if let Err(e) = resolve_path(path, strip, zero, logical, can_mode) {
             if !quiet {
                 show_error!("{}: {}", e, path.display());
             }
@@ -92,6 +101,24 @@ pub fn uu_app() -> App<'static, 'static> {
                 .overrides_with_all(&[OPT_STRIP, OPT_LOGICAL])
                 .help("resolve symlinks as encountered (default)"),
         )
+        .arg(
+            Arg::with_name(OPT_CANONICALIZE_EXISTING)
+                .short("e")
+                .long(OPT_CANONICALIZE_EXISTING)
+                .help(
+                    "canonicalize by following every symlink in every component of the \
+                     given name recursively, all components must exist",
+                ),
+        )
+        .arg(
+            Arg::with_name(OPT_CANONICALIZE_MISSING)
+                .short("m")
+                .long(OPT_CANONICALIZE_MISSING)
+                .help(
+                    "canonicalize by following every symlink in every component of the \
+                     given name recursively, without requirements on components existence",
+                ),
+        )
         .arg(
             Arg::with_name(ARG_FILES)
                 .multiple(true)
@@ -112,7 +139,13 @@ pub fn uu_app() -> App<'static, 'static> {
 ///
 /// This function returns an error if there is a problem resolving
 /// symbolic links.
-fn resolve_path(p: &Path, strip: bool, zero: bool, logical: bool) -> std::io::Result<()> {
+fn resolve_path(
+    p: &Path,
+    strip: bool,
+    zero: bool,
+    logical: bool,
+    can_mode: MissingHandling,
+) -> std::io::Result<()> {
     let resolve = if strip {
         ResolveMode::None
     } else if logical {
@@ -120,7 +153,7 @@ fn resolve_path(p: &Path, strip: bool, zero: bool, logical: bool) -> std::io::Re
     } else {
         ResolveMode::Physical
     };
-    let abs = canonicalize(p, MissingHandling::Normal, resolve)?;
+    let abs = canonicalize(p, can_mode, resolve)?;
     let line_ending = if zero { '\0' } else { '\n' };
 
     print!("{}{}", abs.display(), line_ending);
diff --git a/tests/by-util/test_realpath.rs b/tests/by-util/test_realpath.rs
index 7b6da5d36..72bf5b6ea 100644
--- a/tests/by-util/test_realpath.rs
+++ b/tests/by-util/test_realpath.rs
@@ -1,5 +1,9 @@
 use crate::common::util::*;
 
+use std::path::Path;
+
+static GIBBERISH: &str = "supercalifragilisticexpialidocious";
+
 #[test]
 fn test_realpath_current_directory() {
     let (at, mut ucmd) = at_and_ucmd!();
@@ -159,3 +163,42 @@ fn test_realpath_loop() {
         .succeeds()
         .stdout_only(at.plus_as_string("2\n"));
 }
+
+#[test]
+fn test_realpath_default_allows_final_non_existent() {
+    let p = Path::new("").join(GIBBERISH);
+    let (at, mut ucmd) = at_and_ucmd!();
+    let expect = path_concat!(at.root_dir_resolved(), p.to_str().unwrap()) + "\n";
+    ucmd.arg(p.as_os_str()).succeeds().stdout_only(expect);
+}
+
+#[test]
+fn test_realpath_default_forbids_non_final_non_existent() {
+    let p = Path::new("").join(GIBBERISH).join(GIBBERISH);
+    new_ucmd!().arg(p.to_str().unwrap()).fails();
+}
+
+#[test]
+fn test_realpath_existing() {
+    let (at, mut ucmd) = at_and_ucmd!();
+    ucmd.arg("-e")
+        .arg(".")
+        .succeeds()
+        .stdout_only(at.plus_as_string(&format!("{}\n", at.root_dir_resolved())));
+}
+
+#[test]
+fn test_realpath_existing_error() {
+    new_ucmd!().arg("-e").arg(GIBBERISH).fails();
+}
+
+#[test]
+fn test_realpath_missing() {
+    let p = Path::new("").join(GIBBERISH).join(GIBBERISH);
+    let (at, mut ucmd) = at_and_ucmd!();
+    let expect = path_concat!(at.root_dir_resolved(), p.to_str().unwrap()) + "\n";
+    ucmd.arg("-m")
+        .arg(p.as_os_str())
+        .succeeds()
+        .stdout_only(expect);
+}