feat: broad snapshot id for the cat command

Author: nardoor

crates/core/src/commands/cat.rs

@@ -3,6 +3,7 @@ use std::path::Path;
 use bytes::Bytes;
 
 use crate::{
+    Progress,
     backend::{FileType, FindInBackend, decrypt::DecryptReadBackend},
     blob::{BlobId, BlobType, tree::Tree},
     error::{ErrorKind, RusticError, RusticResult},
@@ -24,6 +25,7 @@ use crate::{
 /// * `repo` - The repository to read from.
 /// * `tpe` - The type of the file.
 /// * `id` - The id of the file.
+///     * the `id` can **also** be in the `latest` or `latest~N` (with N >= 0) for `tpe=FileType::SnapshotFile`
 ///
 /// # Errors
 ///
@@ -38,8 +40,17 @@ pub(crate) fn cat_file<P, S: Open>(
     repo: &Repository<P, S>,
     tpe: FileType,
     id: &str,
-) -> RusticResult<Bytes> {
-    let id = repo.dbe().find_id(tpe, id)?;
+) -> RusticResult<Bytes>
+where
+    P: Progress,
+{
+    // For SnapshotFile, using `SnapshotFile::from_str` allows `latest~N` syntax
+    let id = if let FileType::Snapshot = tpe {
+        let snap_file = SnapshotFile::from_str(repo.dbe(), id, |_| true, &repo.pb)?;
+        snap_file.id.into_inner()
+    } else {
+        repo.dbe().find_id(tpe, id)?
+    };
     let data = repo.dbe().read_encrypted_full(tpe, &id)?;
     Ok(data)
 }