Implement show-ref subcommand

README.md

@@ -19,6 +19,12 @@ This is a simple attempt at re-creating some of the functionality of the `git` c
     - `-p` flag to show the content of the object (pretty-print)
     - `--allow-unknown-type` flag to allow unknown object types (to be used with `-t` or `-s`).
     - `<object>` argument to specify the object to show.
+- `show-ref` - List references in a local repository.
+    - `--head` flag to include the HEAD reference.
+    - `--tags` flag to show only tags.
+    - `--heads` flag to show only heads.
+    - `--hash=<n>` flag to only show the reference hashes (`n` is the number of characters to show, 4-40).
+    - `--abbrev=<n>` flag to abbreviate the hashes to `n` characters (4-40)
 
 ## Testing
 

src/commands/init.rs

@@ -23,7 +23,7 @@ impl CommandArgs for InitArgs {
         std::fs::create_dir_all(object_dir)?;
         std::fs::create_dir(init_path.join("refs"))?;
 
-        // Create the HEAD file with the initial branch.
+        // Create the main HEAD file.
         std::fs::write(
             init_path.join("HEAD"),
             get_head_ref_content(&self.initial_branch),

src/commands/mod.rs

@@ -5,6 +5,7 @@ use clap::Subcommand;
 mod cat_file;
 mod hash_object;
 mod init;
+mod show_ref;
 
 impl Command {
     pub fn run(self) -> anyhow::Result<()> {
@@ -14,6 +15,7 @@ impl Command {
             Command::HashObject(args) => args.run(&mut stdout),
             Command::Init(args) => args.run(&mut stdout),
             Command::CatFile(args) => args.run(&mut stdout),
+            Command::ShowRef(args) => args.run(&mut stdout),
         }
     }
 }
@@ -23,6 +25,7 @@ pub(crate) enum Command {
     HashObject(hash_object::HashObjectArgs),
     Init(init::InitArgs),
     CatFile(cat_file::CatFileArgs),
+    ShowRef(show_ref::ShowRefArgs),
 }
 
 pub(crate) trait CommandArgs {