step thirty two: create RefValue container

src/base.rs

@@ -72,14 +72,20 @@ pub fn commit(message: &str) -> String {
     let mut commit = format!("tree {}\n", write_tree(".".to_owned()));
 
     if let Ok(head) = data::get_ref("HEAD".to_owned()) {
-        commit += format!("parent {}\n", head).as_str();
+        commit += format!("parent {}\n", head.value).as_str();
     }
 
     commit += "\n";
     commit += format!("{}\n", message).as_str();
 
     let oid = data::hash_object(&commit.into_bytes(), "commit".to_owned());
-    data::update_ref("HEAD".to_owned(), oid.clone());
+    data::update_ref(
+        "HEAD".to_owned(),
+        data::RefValue {
+            value: oid.clone(),
+            symbolic: false,
+        },
+    );
     return oid;
 }
 
@@ -132,11 +138,23 @@ pub fn iter_commits_and_parents(mut oids: VecDeque<String>) -> Vec<String> {
 pub fn checkout(oid: String) {
     let commit = get_commit(oid.clone());
     read_tree(commit.tree);
-    data::update_ref("HEAD".to_owned(), oid);
+    data::update_ref(
+        "HEAD".to_owned(),
+        data::RefValue {
+            value: oid,
+            symbolic: false,
+        },
+    );
 }
 
 pub fn create_tag(name: String, oid: String) {
-    data::update_ref(format!("refs/tags/{}", name), oid);
+    data::update_ref(
+        format!("refs/tags/{}", name),
+        data::RefValue {
+            value: oid,
+            symbolic: false,
+        },
+    );
 }
 
 pub fn get_oid(mut name: String) -> String {
@@ -153,7 +171,7 @@ pub fn get_oid(mut name: String) -> String {
 
     for reference in refs_to_try.into_iter() {
         match data::get_ref(reference.clone()) {
-            Ok(oid) => return oid,
+            Ok(oid) => return oid.value,
             _ => continue,
         }
     }
@@ -173,7 +191,13 @@ pub fn get_oid(mut name: String) -> String {
 }
 
 pub fn create_branch(name: String, oid: String) {
-    data::update_ref(format!("refs/heads/{}", name), oid);
+    data::update_ref(
+        format!("refs/heads/{}", name),
+        data::RefValue {
+            value: oid,
+            symbolic: false,
+        },
+    );
 }
 
 fn is_ignored(path: &String) -> bool {

src/data.rs

@@ -6,6 +6,11 @@ use walkdir::WalkDir;
 
 static RGIT_DIR: &'static str = ".rgit";
 
+pub struct RefValue {
+    pub value: String,
+    pub symbolic: bool,
+}
+
 pub fn init() -> std::io::Result<()> {
     fs::create_dir(RGIT_DIR)?;
     fs::create_dir(format!("{}/{}", RGIT_DIR, "objects"))?;
@@ -44,17 +49,18 @@ pub fn get_object(hash: String, expected: String) -> String {
     return data;
 }
 
-pub fn update_ref(reference: String, oid: String) {
+pub fn update_ref(reference: String, value: RefValue) {
+    assert!(!value.symbolic);
     let path = format!("{}/{}", RGIT_DIR, reference);
     let mut parents = Path::new(&path).ancestors();
     parents.next();
 
     let parent = parents.next().unwrap().to_str().unwrap();
     fs::create_dir_all(parent).expect("Cannot create required dirs");
-    fs::write(path, oid).expect("Failed to updated HEAD");
+    fs::write(path, value.value).expect("Failed to updated HEAD");
 }
 
-pub fn get_ref(reference: String) -> Result<String, Box<dyn std::error::Error + 'static>> {
+pub fn get_ref(reference: String) -> Result<RefValue, Box<dyn std::error::Error + 'static>> {
     let ref_path = format!("{}/{}", RGIT_DIR, reference);
     let value = fs::read_to_string(ref_path)?;
 
@@ -62,11 +68,15 @@ pub fn get_ref(reference: String) -> Result<String, Box<dyn std::error::Error +
         let new_ref: Vec<&str> = value.splitn(2, ":").collect();
         return get_ref(new_ref[1].to_owned());
     }
-    return Ok(value);
+
+    return Ok(RefValue {
+        value,
+        symbolic: false,
+    });
 }
 
-pub fn iter_refs() -> Vec<(String, String)> {
+pub fn iter_refs() -> Vec<(String, RefValue)> {
-    let mut refs: Vec<(String, String)> = vec![];
+    let mut refs: Vec<(String, RefValue)> = vec![];
     refs.push(("HEAD".to_owned(), get_ref("HEAD".to_owned()).unwrap()));
 
     for entry in WalkDir::new(format!("{}/refs/", RGIT_DIR)) {

src/main.rs

@@ -166,8 +166,8 @@ fn k() {
     let mut oids = VecDeque::new();
     for refinfo in data::iter_refs() {
         dot.push_str(&format!("\"{}\" [shape=note]\n", refinfo.0));
-        dot.push_str(&format!("\"{}\" -> \"{}\"", refinfo.0, refinfo.1));
+        dot.push_str(&format!("\"{}\" -> \"{}\"", refinfo.0, refinfo.1.value));
-        oids.push_back(refinfo.1);
+        oids.push_back(refinfo.1.value);
     }
 
     for oid in base::iter_commits_and_parents(oids) {