From ba6bd7aac95bf4e8ce9a21a6959f73f064167f10 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gon=C3=A7alo=20Val=C3=A9rio?= <gon@ovalerio.net>
Date: Sat, 7 Nov 2020 22:06:42 +0000
Subject: [PATCH] step twenty nine: log, use iter_commits_and_parents

---
 src/base.rs | 10 +++++-----
 src/main.rs | 14 +++++++-------
 2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/src/base.rs b/src/base.rs
index 0a5a4bc..53c3cd9 100644
--- a/src/base.rs
+++ b/src/base.rs
@@ -1,4 +1,4 @@
-use std::collections::{HashMap, HashSet};
+use std::collections::{HashMap, HashSet, VecDeque};
 use std::fs;
 use std::io;
 use std::path::Path;
@@ -109,13 +109,12 @@ pub fn get_commit(oid: String) -> Commit {
     };
 }
 
-pub fn iter_commits_and_parents(mut oids: HashSet<String>) -> Vec<String> {
+pub fn iter_commits_and_parents(mut oids: VecDeque<String>) -> Vec<String> {
     let mut visited: HashSet<String> = HashSet::new();
     let mut oid_sequence = vec![];
 
     while !oids.is_empty() {
-        let oid = oids.iter().next().cloned().unwrap();
-        oids.remove(&oid);
+        let oid = oids.pop_front().unwrap();
         if oid == "" || visited.contains(&oid) {
             continue;
         }
@@ -123,7 +122,8 @@ pub fn iter_commits_and_parents(mut oids: HashSet<String>) -> Vec<String> {
         oid_sequence.push(oid.clone());
 
         let commit = get_commit(oid);
-        oids.insert(commit.parent);
+        // Deal with parent next
+        oids.push_front(commit.parent);
     }
 
     return oid_sequence;
diff --git a/src/main.rs b/src/main.rs
index d6bf04f..51fa5e2 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,5 +1,5 @@
 use clap::{App, Arg, ArgMatches, SubCommand};
-use std::collections::HashSet;
+use std::collections::{HashSet, VecDeque};
 use std::fs;
 use std::io::Write;
 use std::process::{Command, Stdio};
@@ -120,9 +120,11 @@ 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 oid = base::get_oid(provided_ref.to_owned());
+        let initial_oid = base::get_oid(provided_ref.to_owned());
+        let mut oids = VecDeque::new();
+        oids.push_back(initial_oid);
 
-        loop {
+        for oid in base::iter_commits_and_parents(oids) {
             let commit = base::get_commit(oid.clone());
 
             println!("commit {}", oid);
@@ -132,8 +134,6 @@ fn log_commits(matches: ArgMatches) {
             if commit.parent == "" {
                 break;
             }
-
-            oid = commit.parent;
         }
     }
 }
@@ -156,11 +156,11 @@ fn tag(matches: ArgMatches) {
 
 fn k() {
     let mut dot = "digraph commits {\n".to_owned();
-    let mut oids = HashSet::new();
+    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));
-        oids.insert(refinfo.1);
+        oids.push_back(refinfo.1);
     }
 
     for oid in base::iter_commits_and_parents(oids) {