Set repository mtime to GitHub `updated_at` time

CGit reads the repository modification time from the following
locations, in order from top to bottom:

1. agefile
2. repo.git/refs/heads/{default_branch | "master"}
3. repo.git/packed-refs

(https://git.zx2c4.com/cgit/tree/ui-repolist.c?id=bd6f5683f6cde4212364354b3139c1d521f40f39#n35)

Update the `/refs/heads/{default_branch}` file mtime when cloning and
updating the repo to match the GitHub `updated_at` time.

This ensures that when mirroring old repositories, they don't appear at
the top of the CGit repository index list when sorting by age.

3 files changed, 63 insertions, 5 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 35e7af6..cdb8e4e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -128,6 +128,7 @@ dependencies = [
  "libc",
  "num-integer",
  "num-traits",
+ "time",
  "winapi",
 ]
 
@@ -227,6 +228,18 @@ dependencies = [
 ]
 
 [[package]]
+name = "filetime"
+version = "0.2.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1d34cfa13a63ae058bfa601fe9e313bbdb3746427c1459185464ce0fcf62e1e8"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "redox_syscall",
+ "winapi",
+]
+
+[[package]]
 name = "fnv"
 version = "1.0.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -1010,6 +1023,8 @@ name = "reflectub"
 version = "0.0.1"
 dependencies = [
  "anyhow",
+ "chrono",
+ "filetime",
  "git2",
  "reqwest",
  "serde",
@@ -1412,6 +1427,17 @@ dependencies = [
 ]
 
 [[package]]
+name = "time"
+version = "0.1.44"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6db9e6914ab8b1ae1c260a4ae7a49b6c5611b40328a735b21862567685e73255"
+dependencies = [
+ "libc",
+ "wasi",
+ "winapi",
+]
+
+[[package]]
 name = "tinyvec"
 version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -1615,9 +1641,9 @@ dependencies = [
 
 [[package]]
 name = "wasi"
-version = "0.10.2+wasi-snapshot-preview1"
+version = "0.10.0+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fd6fbd9a79829dd1ad0cc20627bf1ed606756a7f77edff7b66b7064f9cb327c6"
+checksum = "1a143597ca7c7793eff794def352d41792a93c481eb1042423ff7ff72ba2c31f"
 
 [[package]]
 name = "wasm-bindgen"
diff --git a/Cargo.toml b/Cargo.toml
index 854cc11..18ec2a4 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -5,6 +5,8 @@ edition = "2018"
 
 [dependencies]
 anyhow = "1.0.40"
+chrono = "0.4.19"
+filetime = "0.2.14"
 git2 = "0.13.20"
 reqwest = { version = "0.11.3", features = ["json"] }
 serde = { version = "1.0.126", features = ["derive"] }
diff --git a/src/main.rs b/src/main.rs
index 9689d3c..bae2da8 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,4 +1,6 @@
 use anyhow::{self, Context};
+use chrono::DateTime;
+use filetime;
 use sqlx;
 use tokio;
 
@@ -10,9 +12,9 @@ use std::path::{Path, PathBuf};
 
 #[tokio::main]
 async fn main() {
-    let repos = github::fetch_repos("teddywing").await.unwrap();
-
-    dbg!(&repos);
+    // let repos = github::fetch_repos("teddywing").await.unwrap();
+    //
+    // dbg!(&repos);
 
     // git::mirror(
     //     "https://github.com/teddywing/google-calendar-rsvp.git",
@@ -22,6 +24,8 @@ async fn main() {
     // git::update(
     //     Path::new("/tmp/grsvp"),
     // ).unwrap();
+
+    run().await.unwrap();
 }
 
 async fn run() -> anyhow::Result<()> {
@@ -129,6 +133,8 @@ fn mirror<P: AsRef<Path>>(
             ))?;
     }
 
+    update_mtime(&clone_path, &repo)?;
+
     Ok(())
 }
 
@@ -145,5 +151,29 @@ fn update<P: AsRef<Path>>(
         git::update_description(&repo_path, remote_description)?;
     }
 
+    update_mtime(&repo_path, &updated_repo)?;
+
+    Ok(())
+}
+
+fn update_mtime<P: AsRef<Path>>(
+    repo_path: P,
+    repo: &github::Repo,
+) -> anyhow::Result<()> {
+    let default_branch_ref = repo_path
+        .as_ref()
+        .join("refs/heads")
+        .join(&repo.default_branch);
+
+    let update_time = filetime::FileTime::from_system_time(
+        DateTime::parse_from_rfc3339(&repo.updated_at)?.into()
+    );
+
+    filetime::set_file_times(&default_branch_ref, update_time, update_time)
+        .with_context(|| format!(
+            "unable to set mtime on '{}'",
+            &default_branch_ref.display(),
+        ))?;
+
     Ok(())
 }