refactor(cache): redesign cache system with structured keys and improved performance

- Add repo_path parameter to cached_response and cached_vec_response functions
- Implement structured cache key format with namespace, repo_path, and request proto
- Replace global cache with Moka in-memory cache using weight-based eviction
- Set 256MB memory cap with 10-minute TTL and 2-minute TTI policy
- Add metrics collection for cache operations and evictions
- Implement efficient repo-scoped invalidation using key structure
- Add detailed documentation comments explaining cache architecture
- Remove outdated dependencies and update dependency versions
- Add error handling for encoding failures in cache operations
- Optimize Vec responses with length-delimited encoding and pre-allocation

snapshot/mod.rs

@@ -8,6 +8,7 @@
 
 pub mod ops;
 pub mod storage;
+pub mod sync;
 
 pub use ops::{create_snapshot, restore_snapshot, verify_snapshot};
 pub use storage::{LocalSnapshotStorage, SnapshotInfo, SnapshotStorageBackend};

snapshot/ops.rs

@@ -81,7 +81,7 @@ pub fn create_and_store_snapshot(
 pub fn restore_snapshot(repo_path: &Path, data: &[u8]) -> GitResult<()> {
     tracing::info!(path = %repo_path.display(), size_bytes = data.len(), "restoring snapshot");
 
-    let applicator = crate::actor::sync::BundleApplicator::new(repo_path.to_path_buf());
+    let applicator = crate::snapshot::sync::BundleApplicator::new(repo_path.to_path_buf());
     applicator.apply_bundle(data).map_err(GitError::Internal)?;
 
     tracing::info!(path = %repo_path.display(), "snapshot restored");
@@ -163,7 +163,7 @@ fn generate_snapshot_id(relative_path: &str, head_oid: &str) -> String {
     let mut s = String::with_capacity(16);
     for byte in &hash[..8] {
         use std::fmt::Write;
-        write!(s, "{byte:02x}").unwrap();
+        let _ = write!(s, "{byte:02x}");
     }
     s
 }

snapshot/storage.rs

@@ -40,8 +40,22 @@ impl LocalSnapshotStorage {
         Self { base_dir }
     }
 
+    fn validate_snapshot_id(snapshot_id: &str) -> Result<(), String> {
+        if snapshot_id.is_empty() {
+            return Err("snapshot_id cannot be empty".into());
+        }
+        if snapshot_id.len() > 64
+            || !snapshot_id
+                .chars()
+                .all(|c| c.is_ascii_alphanumeric() || c == '-' || c == '_')
+        {
+            return Err(format!("invalid snapshot_id: {snapshot_id}"));
+        }
+        Ok(())
+    }
+
     fn snapshot_dir(&self, snapshot_id: &str) -> PathBuf {
-        let prefix = &snapshot_id[..2.min(snapshot_id.len())];
+        let prefix = snapshot_id.get(..2).unwrap_or(snapshot_id);
         self.base_dir.join(prefix).join(snapshot_id)
     }
 
@@ -62,6 +76,7 @@ impl SnapshotStorageBackend for LocalSnapshotStorage {
         head_oid: &str,
         data: &[u8],
     ) -> Result<(), String> {
+        Self::validate_snapshot_id(snapshot_id)?;
         let dir = self.snapshot_dir(snapshot_id);
         std::fs::create_dir_all(&dir).map_err(|e| format!("create dir: {e}"))?;
 
@@ -95,6 +110,7 @@ impl SnapshotStorageBackend for LocalSnapshotStorage {
     }
 
     fn read_snapshot(&self, snapshot_id: &str) -> Result<Vec<u8>, String> {
+        Self::validate_snapshot_id(snapshot_id)?;
         let path = self.data_path(snapshot_id);
         if !path.exists() {
             return Err(format!("snapshot not found: {snapshot_id}"));
@@ -155,6 +171,7 @@ impl SnapshotStorageBackend for LocalSnapshotStorage {
     }
 
     fn delete_snapshot(&self, snapshot_id: &str) -> Result<(), String> {
+        Self::validate_snapshot_id(snapshot_id)?;
         let dir = self.snapshot_dir(snapshot_id);
         if !dir.exists() {
             return Err(format!("snapshot not found: {snapshot_id}"));

snapshot/sync.rs

@@ -0,0 +1,95 @@
+//! Bundle applicator for restoring snapshots to git repositories.
+//!
+//! Uses `git bundle unbundle` to apply pack data to a bare repository.
+
+use std::path::{Path, PathBuf};
+
+pub struct BundleApplicator {
+    pub repo_path: PathBuf,
+}
+
+impl BundleApplicator {
+    pub fn new(repo_path: PathBuf) -> Self {
+        Self { repo_path }
+    }
+
+    pub fn apply_bundle(&self, data: &[u8]) -> Result<(), String> {
+        let mut child = std::process::Command::new("git")
+            .args([
+                "--git-dir",
+                &self.repo_path.to_string_lossy(),
+                "bundle",
+                "unbundle",
+                "-",
+            ])
+            .stdin(std::process::Stdio::piped())
+            .stdout(std::process::Stdio::piped())
+            .stderr(std::process::Stdio::piped())
+            .spawn()
+            .map_err(|e| format!("spawn git bundle unbundle: {e}"))?;
+        use std::io::Write;
+        if let Some(ref mut stdin) = child.stdin {
+            stdin
+                .write_all(data)
+                .map_err(|e| format!("write bundle: {e}"))?;
+        }
+        let output = child
+            .wait_with_output()
+            .map_err(|e| format!("wait bundle: {e}"))?;
+        if !output.status.success() {
+            return Err(String::from_utf8_lossy(&output.stderr).into_owned());
+        }
+        Ok(())
+    }
+
+    /// Apply bundle from a file path (for streaming writes).
+    pub fn apply_bundle_from_file(&self, path: &Path) -> Result<(), String> {
+        let file = std::fs::File::open(path).map_err(|e| format!("open bundle file: {e}"))?;
+        let mut child = std::process::Command::new("git")
+            .args([
+                "--git-dir",
+                &self.repo_path.to_string_lossy(),
+                "bundle",
+                "unbundle",
+                "-",
+            ])
+            .stdin(std::process::Stdio::piped())
+            .stdout(std::process::Stdio::piped())
+            .stderr(std::process::Stdio::piped())
+            .spawn()
+            .map_err(|e| format!("spawn git bundle unbundle: {e}"))?;
+
+        // Stream file contents to stdin in a background thread
+        let mut stdin = child.stdin.take().ok_or("no stdin")?;
+        let file_handle = file;
+        let writer = std::thread::spawn(move || -> Result<(), String> {
+            use std::io::{Read, Write};
+            let mut reader = std::io::BufReader::new(file_handle);
+            let mut buf = vec![0u8; 65536];
+            loop {
+                match reader.read(&mut buf) {
+                    Ok(0) => break,
+                    Ok(n) => {
+                        stdin
+                            .write_all(&buf[..n])
+                            .map_err(|e| format!("write to stdin: {e}"))?;
+                    }
+                    Err(e) => return Err(format!("read bundle file: {e}")),
+                }
+            }
+            Ok(())
+        });
+
+        let output = child
+            .wait_with_output()
+            .map_err(|e| format!("wait bundle: {e}"))?;
+
+        // Wait for writer thread
+        let _ = writer.join().map_err(|_| "writer thread panicked")?;
+
+        if !output.status.success() {
+            return Err(String::from_utf8_lossy(&output.stderr).into_owned());
+        }
+        Ok(())
+    }
+}