From 3430b7c5d480f182d26ccb6142d889534521306c Mon Sep 17 00:00:00 2001
From: Jordan Doyle <jordan@doyle.la>
Date: Wed, 13 Nov 2024 01:22:48 +0000
Subject: [PATCH] Avoid mutating vector to determine endpoint

This change also fixes a long standing bug with directories named `tree`
in the repository tree causing a "repository not found" error to be
returned.
---
 src/main.rs             |  8 +-------
 src/methods/repo/mod.rs | 82 +++++++++++++++++++++++++++++++++++++++++++++++++-------------------------------
 2 files changed, 48 insertions(+), 42 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index 20d0826..e803443 100644
--- a/src/main.rs
+++ a/src/main.rs
@@ -241,13 +241,7 @@
         let mut commit_family_options = Options::default();
         commit_family_options.set_prefix_extractor(SliceTransform::create(
             "commit_prefix",
-            |input| {
-                if let Some(offset) = memchr::memchr(b'\0', input) {
-                    &input[offset + 1..]
-                } else {
-                    input
-                }
-            },
+            |input| memchr::memchr(b'\0', input).map_or(input, |idx| &input[..idx]),
             None,
         ));
 
diff --git a/src/methods/repo/mod.rs b/src/methods/repo/mod.rs
index 43ac306..72ece11 100644
--- a/src/methods/repo/mod.rs
+++ a/src/methods/repo/mod.rs
@@ -13,7 +13,7 @@
     collections::BTreeMap,
     ops::Deref,
     path::{Path, PathBuf},
-    sync::Arc,
+    sync::{Arc, LazyLock},
 };
 
 use axum::{
@@ -53,14 +53,6 @@
         .get::<Arc<PathBuf>>()
         .expect("scan_path missing");
 
-    let mut uri_parts: Vec<&str> = request
-        .uri()
-        .path()
-        .trim_start_matches('/')
-        .trim_end_matches('/')
-        .split('/')
-        .collect();
-
     let mut child_path = None;
 
     macro_rules! h {
@@ -68,15 +60,36 @@
             BoxCloneService::new($handler.into_service())
         };
     }
+
+    let uri = request
+        .uri()
+        .path()
+        .trim_start_matches('/')
+        .trim_end_matches('/');
+    let mut uri_parts = memchr::memchr_iter(b'/', uri.as_bytes());
+
+    let original_uri = uri;
+    let (action, mut uri) = if let Some(idx) = uri_parts.next_back() {
+        (uri.get(idx + 1..), &uri[..idx])
+    } else {
+        (None, uri)
+    };
 
-    let mut service = match uri_parts.pop() {
+    let mut service = match action {
         Some("about") => h!(handle_about),
-        Some("refs") if uri_parts.last() == Some(&"info") => {
-            uri_parts.pop();
-            h!(handle_smart_git)
-        }
         Some("git-upload-pack") => h!(handle_smart_git),
-        Some("refs") => h!(handle_refs),
+        Some("refs") => {
+            if let Some(idx) = uri_parts.next_back() {
+                if uri.get(idx + 1..) == Some("info") {
+                    uri = &uri[..idx];
+                    h!(handle_smart_git)
+                } else {
+                    h!(handle_refs)
+                }
+            } else {
+                h!(handle_refs)
+            }
+        }
         Some("log") => h!(handle_log),
         Some("tree") => h!(handle_tree),
         Some("commit") => h!(handle_commit),
@@ -84,35 +97,26 @@
         Some("patch") => h!(handle_patch),
         Some("tag") => h!(handle_tag),
         Some("snapshot") => h!(handle_snapshot),
-        Some(v) => {
-            uri_parts.push(v);
-
-            // match tree children
-            if uri_parts.iter().any(|v| *v == "tree") {
-                // TODO: this needs fixing up so it doesn't accidentally match repos that have
-                //  `tree` in their path
-                let mut reconstructed_path = Vec::new();
-
-                while let Some(part) = uri_parts.pop() {
-                    if part == "tree" {
-                        break;
-                    }
-
-                    // TODO: FIXME
-                    reconstructed_path.insert(0, part);
-                }
+        Some(_) => {
+            static TREE_FINDER: LazyLock<memchr::memmem::Finder> =
+                LazyLock::new(|| memchr::memmem::Finder::new(b"/tree/"));
 
-                child_path = Some(reconstructed_path.into_iter().collect::<PathBuf>().clean());
+            uri = original_uri;
 
+            // match tree children
+            if let Some(idx) = TREE_FINDER.find(uri.as_bytes()) {
+                // 6 is the length of /tree/
+                child_path = Some(Path::new(&uri[idx + 6..]).clean());
+                uri = &uri[..idx];
                 h!(handle_tree)
             } else {
                 h!(handle_summary)
             }
         }
-        None => panic!("not found"),
+        None => h!(handle_summary),
     };
 
-    let uri = uri_parts.into_iter().collect::<PathBuf>().clean();
+    let uri = Path::new(uri).clean();
     let path = scan_path.join(&uri);
 
     let db = request
@@ -162,6 +166,14 @@
 }
 
 pub type Result<T, E = Error> = std::result::Result<T, E>;
+
+pub struct InvalidRequest;
+
+impl IntoResponse for InvalidRequest {
+    fn into_response(self) -> Response {
+        (StatusCode::NOT_FOUND, "Invalid request").into_response()
+    }
+}
 
 pub struct RepositoryNotFound;
 
--
rgit 0.1.3