samefile: Cache FileInformation for the target (#409)

And don't follow symlinks.

src/find/matchers/mod.rs

@@ -540,16 +540,10 @@ fn build_matcher_tree(
                 if i >= args.len() - 1 {
                     return Err(From::from(format!("missing argument to {}", args[i])));
                 }
-                let path = Path::new(args[i + 1]).to_path_buf();
-                // check if path is not found
-                if !path.exists() {
-                    return Err(From::from(format!(
-                        "{}: No such file or directory",
-                        args[i + 1]
-                    )));
-                }
                 i += 1;
-                Some(SameFileMatcher::new(path).into_box())
+                let path = args[i];
+                let matcher = SameFileMatcher::new(path).map_err(|e| format!("{path}: {e}"))?;
+                Some(matcher.into_box())
             }
             "-user" => {
                 if i >= args.len() - 1 {

src/find/matchers/samefile.rs

@@ -3,23 +3,29 @@
 // For the full copyright and license information, please view the LICENSE
 // file that was distributed with this source code.
 
-use std::path::PathBuf;
-
 use super::Matcher;
+use std::error::Error;
+use std::path::Path;
+use uucore::fs::FileInformation;
 
 pub struct SameFileMatcher {
-    path: PathBuf,
+    info: FileInformation,
 }
 
 impl SameFileMatcher {
-    pub fn new(path: PathBuf) -> SameFileMatcher {
-        SameFileMatcher { path }
+    pub fn new(path: impl AsRef<Path>) -> Result<Self, Box<dyn Error>> {
+        let info = FileInformation::from_path(path, false)?;
+        Ok(Self { info })
     }
 }
 
 impl Matcher for SameFileMatcher {
     fn matches(&self, file_info: &walkdir::DirEntry, _matcher_io: &mut super::MatcherIO) -> bool {
-        uucore::fs::paths_refer_to_same_file(file_info.path(), &self.path, true)
+        if let Ok(info) = FileInformation::from_path(file_info.path(), false) {
+            info == self.info
+        } else {
+            false
+        }
     }
 }
 
@@ -38,11 +44,14 @@ mod tests {
         // But you can't delete a file that doesn't exist,
         // so ignore the error returned here.
         let _ = fs::remove_file("test_data/links/hard_link");
+
+        assert!(SameFileMatcher::new("test_data/links/hard_link").is_err());
+
         fs::hard_link("test_data/links/abbbc", "test_data/links/hard_link").unwrap();
 
         let file = get_dir_entry_for("test_data/links", "abbbc");
         let hard_link_file = get_dir_entry_for("test_data/links", "hard_link");
-        let matcher = SameFileMatcher::new(file.into_path());
+        let matcher = SameFileMatcher::new(file.into_path()).unwrap();
 
         let deps = FakeDependencies::new();
         assert!(matcher.matches(&hard_link_file, &mut deps.new_matcher_io()));

tests/find_cmd_tests.rs

@@ -878,6 +878,6 @@ fn find_samefile() {
         .args([".", "-samefile", "./test_data/links/not-exist-file"])
         .assert()
         .failure()
-        .stdout(predicate::str::contains(""))
-        .stderr(predicate::str::contains("No such file or directory"));
+        .stdout(predicate::str::is_empty())
+        .stderr(predicate::str::contains("not-exist-file"));
 }