From 6595e8c4a50c9b8bab72aed3ad355538a5e92a63 Mon Sep 17 00:00:00 2001
From: Jordan Doyle <jordan@doyle.la>
Date: Wed, 13 Nov 2024 02:16:15 +0000
Subject: [PATCH] Remove intermediary vecs/btreemaps for ordering on index

---
 Cargo.lock           |  2 +-
 src/methods/index.rs | 57 ++++++++++++++++++++++++++++++--------------
 templates/index.html | 16 ++++++-------
 3 files changed, 48 insertions(+), 27 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 8427b33..27dbd71 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,6 +1,6 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-version = 4
+version = 3
 
 [[package]]
 name = "addr2line"
diff --git a/src/methods/index.rs b/src/methods/index.rs
index 2bd3ac8..592001f 100644
--- a/src/methods/index.rs
+++ b/src/methods/index.rs
@@ -1,8 +1,12 @@
-use std::{collections::BTreeMap, sync::Arc};
+use std::{cell::RefCell, sync::Arc};
 
 use anyhow::Context;
 use askama::Template;
-use axum::{response::IntoResponse, Extension};
+use axum::{
+    response::{IntoResponse, Response},
+    Extension,
+};
+use itertools::{Either, Itertools};
 
 use super::filters;
 use crate::{
@@ -12,28 +16,45 @@ use crate::{
 
 #[derive(Template)]
 #[template(path = "index.html")]
-pub struct View {
-    pub repositories: BTreeMap<Option<String>, Vec<YokedRepository>>,
+pub struct View<
+    'a,
+    Group: Iterator<Item = (&'a String, &'a YokedRepository)>,
+    GroupIter: Iterator<Item = (&'a str, Group)>,
+> {
+    // this type sig is a necessary evil unfortunately, because askama takes a reference
+    // to the data for rendering.
+    pub repositories: RefCell<Either<GroupIter, std::iter::Empty<(&'a str, Group)>>>,
+}
+
+impl<'a, Group, GroupIter> View<'a, Group, GroupIter>
+where
+    Group: Iterator<Item = (&'a String, &'a YokedRepository)>,
+    GroupIter: Iterator<Item = (&'a str, Group)>,
+{
+    fn take_iter(&self) -> Either<GroupIter, std::iter::Empty<(&'a str, Group)>> {
+        self.repositories.replace(Either::Right(std::iter::empty()))
+    }
 }
 
 pub async fn handle(
     Extension(db): Extension<Arc<rocksdb::DB>>,
-) -> Result<impl IntoResponse, super::repo::Error> {
-    let mut repositories: BTreeMap<Option<String>, Vec<YokedRepository>> = BTreeMap::new();
-
+) -> Result<Response, super::repo::Error> {
     let fetched = tokio::task::spawn_blocking(move || Repository::fetch_all(&db))
         .await
         .context("Failed to join Tokio task")??;
 
-    for (k, v) in fetched {
-        // TODO: fixme
-        let mut split: Vec<_> = k.split('/').collect();
-        split.pop();
-        let key = Some(split.join("/")).filter(|v| !v.is_empty());
-
-        let k = repositories.entry(key).or_default();
-        k.push(v);
-    }
-
-    Ok(into_response(View { repositories }))
+    // rocksdb returned the keys already ordered for us so group_by is a nice
+    // operation we can use here to avoid writing into a map to group. though,
+    // now that i think about it it might act a little bit strangely when mixing
+    // root repositories and nested repositories. we're going to have to prefix
+    // root repositories with a null byte or something. i'll just leave this here
+    // as a TODO.
+    let repositories = fetched
+        .iter()
+        .group_by(|(k, _)| memchr::memrchr(b'/', k.as_bytes()).map_or("", |idx| &k[..idx]));
+
+    Ok(into_response(View {
+        repositories: Either::Left(repositories.into_iter()).into(),
+    })
+    .into_response())
 }
diff --git a/templates/index.html b/templates/index.html
index e9762a6..2abf597 100644
--- a/templates/index.html
+++ b/templates/index.html
@@ -13,21 +13,21 @@
         </thead>
 
         <tbody>
-        {%- for (path, repositories) in repositories %}
-            {%- if let Some(path) = path %}
+        {%- for (path, repositories) in self.take_iter() %}
+            {%- if !path.is_empty() %}
             <tr><td class="repo-section" colspan="4">{{ path }}</td></tr>
             {%- endif -%}
 
             {%- for repository in repositories %}
-            {% set repository = repository.get() %}
-            <tr class="{% if path.is_some() %}has-parent{% endif %}">
+            {% set repository = repository.1.get() %}
+            <tr class="{% if !path.is_empty() %}has-parent{% endif %}">
                 <td>
-                    <a href="/{% if let Some(path) = path %}{{ path }}/{% endif %}{{ repository.name }}">
+                    <a href="/{% if !path.is_empty() %}{{ path }}/{% endif %}{{ repository.name }}">
                         {{- repository.name -}}
                     </a>
                 </td>
                 <td>
-                    <a href="/{% if let Some(path) = path %}{{ path }}/{% endif %}{{ repository.name }}">
+                    <a href="/{% if !path.is_empty() %}{{ path }}/{% endif %}{{ repository.name }}">
                         {%- if let Some(description) = repository.description.as_ref() -%}
                             {{- description -}}
                         {%- else -%}
@@ -36,14 +36,14 @@
                     </a>
                 </td>
                 <td>
-                    <a href="/{% if let Some(path) = path %}{{ path }}/{% endif %}{{ repository.name }}">
+                    <a href="/{% if !path.is_empty() %}{{ path }}/{% endif %}{{ repository.name }}">
                         {%- if let Some(owner) = repository.owner.as_ref() -%}
                             {{- owner -}}
                         {%- endif -%}
                     </a>
                 </td>
                 <td>
-                    <a href="/{% if let Some(path) = path %}{{ path }}/{% endif %}{{ repository.name }}">
+                    <a href="/{% if !path.is_empty() %}{{ path }}/{% endif %}{{ repository.name }}">
                         <time datetime="{{ repository.last_modified|format_time }}" title="{{ repository.last_modified|format_time }}">
                             {{- repository.last_modified|timeago -}}
                         </time>