step fourty: show refs that point to each commit

src/main.rs

@@ -1,5 +1,5 @@
 use clap::{App, Arg, ArgMatches, SubCommand};
-use std::collections::{HashSet, VecDeque};
+use std::collections::{HashMap, HashSet, VecDeque};
 use std::fs;
 use std::io::Write;
 use std::process::{Command, Stdio};
@@ -129,6 +129,16 @@ fn commit(matches: ArgMatches) {
 fn log_commits(matches: ArgMatches) {
     if let Some(cmd_matches) = matches.subcommand_matches("log") {
         let provided_ref = cmd_matches.value_of("oid").unwrap().to_owned();
+
+        let mut refs: HashMap<String, Vec<String>> = HashMap::new();
+        for entry in data::iter_refs("", true) {
+            if refs.contains_key(&entry.1.value) {
+                refs.get_mut(&entry.1.value).unwrap().push(entry.0);
+            } else {
+                refs.insert(entry.1.value, vec![entry.0]);
+            }
+        }
+
         let initial_oid = base::get_oid(provided_ref.to_owned());
         let mut oids = VecDeque::new();
         oids.push_back(initial_oid);
@@ -136,7 +146,13 @@ fn log_commits(matches: ArgMatches) {
         for oid in base::iter_commits_and_parents(oids) {
             let commit = base::get_commit(oid.clone());
 
-            println!("commit {}", oid);
+            let ref_str = if refs.contains_key(&oid) {
+                refs.get_mut(&oid).unwrap().join(", ")
+            } else {
+                "".to_owned()
+            };
+
+            println!("commit {} {}", oid, ref_str);
             println!("{}", commit.message);
             println!("");