From 416061a632ce08d1bcd25e145be626d2aa62ecea Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gon=C3=A7alo=20Val=C3=A9rio?= <gon@ovalerio.net>
Date: Sun, 6 Dec 2020 17:52:03 +0000
Subject: [PATCH] step fifty nine: download missing objects pointed by remote
 refs

---
 src/base.rs   | 49 ++++++++++++++++++++++++++++++++++++++++++++++++-
 src/data.rs   | 20 ++++++++++++++++++++
 src/remote.rs |  8 +++++++-
 3 files changed, 75 insertions(+), 2 deletions(-)

diff --git a/src/base.rs b/src/base.rs
index 68cb406..de6c59e 100644
--- a/src/base.rs
+++ b/src/base.rs
@@ -159,6 +159,53 @@ pub fn iter_commits_and_parents(mut oids: VecDeque<String>) -> Vec<String> {
     return oid_sequence;
 }
 
+pub fn copy_objects_in_commits_and_parents(mut oids: Vec<&String>, remote_path: String) {
+    // This one is a little be different than the functions in the tutorial
+    // But the end result is the same, copy all missing objects from the remote
+    // repository
+    let mut visited: HashSet<String> = HashSet::new();
+    let mut commits = oids
+        .into_iter()
+        .map(|oid| oid.clone())
+        .rev()
+        .collect::<VecDeque<String>>();
+
+    while !commits.is_empty() {
+        let oid = commits.pop_front().unwrap();
+        if oid == "" || visited.contains(&oid) {
+            continue;
+        }
+
+        data::fetch_object_if_missing(oid.clone(), remote_path.clone());
+        visited.insert(oid.clone());
+
+        let commit = get_commit(oid.clone());
+        copy_tree_objects(commit.tree, &mut visited, remote_path.clone());
+
+        let parent1 = commit.parents[0].clone();
+        // Deal with parent next
+        commits.push_front(parent1);
+        // Deal with other parents later
+        if commit.parents.len() > 1 {
+            let parent2 = commit.parents[1].clone();
+            commits.push_back(parent2);
+        }
+    }
+}
+
+fn copy_tree_objects(oid: String, visited: &mut HashSet<String>, remote_path: String) {
+    // get_tree already walks recursively the provided tree. Lets use that instead.
+    visited.insert(oid.clone());
+    data::fetch_object_if_missing(oid.clone(), remote_path.clone());
+
+    for (path, object_id) in get_tree(oid, "./".to_owned()).iter() {
+        if visited.contains(object_id) {
+            continue;
+        }
+        data::fetch_object_if_missing(object_id.clone(), remote_path.clone());
+    }
+}
+
 pub fn checkout(name: String) {
     let oid = get_oid(name.clone());
     let commit = get_commit(oid.clone());
@@ -206,7 +253,7 @@ pub fn get_oid(mut name: String) -> String {
     for reference in refs_to_try.iter() {
         let found = data::get_ref(reference.clone(), false);
         if found.value != "" {
-            return found.value;
+            return data::get_ref(reference.clone(), true).value;
         } else {
             continue;
         }
diff --git a/src/data.rs b/src/data.rs
index dd28775..57b92c8 100644
--- a/src/data.rs
+++ b/src/data.rs
@@ -159,3 +159,23 @@ pub fn get_ref_internal(reference: String, deref: bool) -> (String, RefValue) {
 
     return (reference, RefValue { value, symbolic });
 }
+
+pub fn fetch_object_if_missing(oid: String, remote_git_dir: String) {
+    if object_exists(oid.clone()) {
+        return;
+    }
+
+    let dir = RGIT_DIR.lock().unwrap().to_owned();
+    let rgit_remote = remote_git_dir + "/.rgit";
+    fs::copy(
+        format!("{}/objects/{}", rgit_remote, oid.clone()),
+        format!("{}/objects/{}", dir, oid),
+    )
+    .expect(format!("Failed to fetch {}", oid).as_str());
+}
+
+fn object_exists(oid: String) -> bool {
+    let dir = RGIT_DIR.lock().unwrap().to_owned();
+    let path = format!("{}/objects/{}", dir.clone(), oid.clone());
+    return Path::new(path.as_str()).exists();
+}
diff --git a/src/remote.rs b/src/remote.rs
index 0ace815..2724c3a 100644
--- a/src/remote.rs
+++ b/src/remote.rs
@@ -3,12 +3,18 @@ use std::collections::HashMap;
 #[path = "data.rs"]
 mod data;
 
+#[path = "base.rs"]
+mod base;
+
 static REMOTE_REFS_BASE: &'static str = "refs/heads/";
 static LOCAL_REFS_BASE: &'static str = "refs/remote/";
 
 pub fn fetch(path: String) {
     // Get refs from server
-    let refs = get_remote_refs(path, REMOTE_REFS_BASE);
+    let refs = get_remote_refs(path.clone(), REMOTE_REFS_BASE);
+
+    let commit_oids: Vec<&String> = refs.values().collect();
+    base::copy_objects_in_commits_and_parents(commit_oids, path.clone());
 
     // Update local refs to match server
     for (remote_name, value) in refs.iter() {