--- a/rust/rhg/src/commands/cat.rs	Thu Dec 19 00:18:33 2024 +0100
+++ b/rust/rhg/src/commands/cat.rs	Mon Dec 16 10:52:01 2024 -0500
@@ -1,10 +1,9 @@
 use crate::error::CommandError;
+use crate::utils::path_utils::resolve_file_args;
 use clap::Arg;
 use format_bytes::format_bytes;
 use hg::operations::cat;
-use hg::utils::hg_path::HgPathBuf;
 use std::ffi::OsString;
-use std::os::unix::prelude::OsStrExt;
 
 pub const HELP_TEXT: &str = "
 Output the current or given revision of files
@@ -40,52 +39,15 @@
         ));
     }
 
-    let rev = invocation.subcommand_args.get_one::<String>("rev");
-    let file_args =
-        match invocation.subcommand_args.get_many::<OsString>("files") {
-            Some(files) => files
-                .filter(|s| !s.is_empty())
-                .map(|s| s.as_os_str())
-                .collect(),
-            None => vec![],
-        };
-
     let repo = invocation.repo?;
-    let cwd = hg::utils::current_dir()?;
-    let working_directory = repo.working_directory_path();
-    let working_directory = cwd.join(working_directory); // Make it absolute
-
-    let mut files = vec![];
-    for file in file_args {
-        if file.as_bytes().starts_with(b"set:") {
-            let message = "fileset";
-            return Err(CommandError::unsupported(message));
-        }
 
-        let normalized = cwd.join(file);
-        // TODO: actually normalize `..` path segments etc?
-        let dotted = normalized.components().any(|c| c.as_os_str() == "..");
-        if file.as_bytes() == b"." || dotted {
-            let message = "`..` or `.` path segment";
-            return Err(CommandError::unsupported(message));
-        }
-        let relative_path = working_directory
-            .strip_prefix(&cwd)
-            .unwrap_or(&working_directory);
-        let stripped = normalized
-            .strip_prefix(&working_directory)
-            .map_err(|_| {
-                CommandError::abort(format!(
-                    "abort: {} not under root '{}'\n(consider using '--cwd {}')",
-                    String::from_utf8_lossy(file.as_bytes()),
-                    working_directory.display(),
-                    relative_path.display(),
-                ))
-            })?;
-        let hg_file = HgPathBuf::try_from(stripped.to_path_buf())
-            .map_err(|e| CommandError::abort(e.to_string()))?;
-        files.push(hg_file);
-    }
+    let rev = invocation.subcommand_args.get_one::<String>("rev");
+    let files = match invocation.subcommand_args.get_many::<OsString>("files")
+    {
+        None => vec![],
+        Some(files) => resolve_file_args(repo, files)?,
+    };
+
     let files = files.iter().map(|file| file.as_ref()).collect();
     // TODO probably move this to a util function like `repo.default_rev` or
     // something when it's used somewhere else