From 138468da3aabfcb6b6febc43f6d287e179f19ca9 Mon Sep 17 00:00:00 2001
From: Kishan Goli <kishangoli@ucsb.edu>
Date: Fri, 15 May 2026 13:19:17 -0700
Subject: [PATCH 1/2] abstract engine away from flatindex

---
 src/api/handlers.rs | 1 -
 src/engine.rs       | 9 +++++----
 src/state.rs        | 6 +++---
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/api/handlers.rs b/src/api/handlers.rs
index 8f49e88..cd9b94b 100644
--- a/src/api/handlers.rs
+++ b/src/api/handlers.rs
@@ -2,7 +2,6 @@ use axum::{extract::State, Json};
 
 use crate::{
     api::response::{bad_request, ApiError, ApiResult},
-    engine::VectorEngine,
     models::{
         DeleteRequest, InsertRequest, MessageResponse, SearchRequest, SearchResponse,
     },
diff --git a/src/engine.rs b/src/engine.rs
index cfacc0c..95fb00c 100644
--- a/src/engine.rs
+++ b/src/engine.rs
@@ -4,6 +4,7 @@ pub trait VectorEngine {
     fn insert(&mut self, id: String, vector: Vec<f32>);
     fn search(&self, query: Vec<f32>, k: usize) -> Vec<SearchResult>;
     fn delete(&mut self, id: &str);
+    fn dimension(&self) -> Option<usize>;
 }
 
 #[derive(Default)]
@@ -15,10 +16,6 @@ impl FlatIndex {
     pub fn new() -> Self {
         Self::default()
     }
-
-    pub fn dimension(&self) -> Option<usize> {
-        self.vectors.first().map(|(_, vector)| vector.len())
-    }
 }
 
 impl VectorEngine for FlatIndex {
@@ -45,6 +42,10 @@ impl VectorEngine for FlatIndex {
     fn delete(&mut self, id: &str) {
         self.vectors.retain(|(stored_id, _)| stored_id != id);
     }
+
+    fn dimension(&self) -> Option<usize> {
+        self.vectors.first().map(|(_, vector)| vector.len())
+    }
 }
 
 fn cosine_similarity(left: &[f32], right: &[f32]) -> f32 {
diff --git a/src/state.rs b/src/state.rs
index ac3c248..9dd4b03 100644
--- a/src/state.rs
+++ b/src/state.rs
@@ -1,16 +1,16 @@
 use std::sync::{Arc, Mutex};
 
-use crate::engine::FlatIndex;
+use crate::engine::{FlatIndex, VectorEngine};
 
 #[derive(Clone)]
 pub struct AppState {
-    pub engine: Arc<Mutex<FlatIndex>>,
+    pub engine: Arc<Mutex<Box<dyn VectorEngine + Send>>>,
 }
 
 impl AppState {
     pub fn new() -> Self {
         Self {
-            engine: Arc::new(Mutex::new(FlatIndex::new())),
+            engine: Arc::new(Mutex::new(Box::new(FlatIndex::new()))),
         }
     }
 }

From cf47132e73671f0d92b33afd28c47e4b5198dcb4 Mon Sep 17 00:00:00 2001
From: Kishan Goli <kishangoli@ucsb.edu>
Date: Fri, 15 May 2026 13:45:37 -0700
Subject: [PATCH 2/2] shell out c++ ffi

---
 Cargo.lock                         | 23 +++++++++++++++++++++++
 Cargo.toml                         |  3 +++
 build.rs                           |  8 ++++++++
 native/include/vector_engine_ffi.h | 13 +++++++++++++
 native/src/vector_engine_ffi.cpp   | 11 +++++++++++
 5 files changed, 58 insertions(+)
 create mode 100644 build.rs
 create mode 100644 native/include/vector_engine_ffi.h
 create mode 100644 native/src/vector_engine_ffi.cpp

diff --git a/Cargo.lock b/Cargo.lock
index e8cd33c..a5089b8 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -72,6 +72,16 @@ version = "1.11.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1e748733b7cbc798e1434b6ac524f0c1ff2ab456fe201501e6497c8417a4fc33"
 
+[[package]]
+name = "cc"
+version = "1.2.62"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a1dce859f0832a7d088c4f1119888ab94ef4b5d6795d1ce05afb7fe159d79f98"
+dependencies = [
+ "find-msvc-tools",
+ "shlex",
+]
+
 [[package]]
 name = "cfg-if"
 version = "1.0.4"
@@ -88,6 +98,12 @@ dependencies = [
  "windows-sys",
 ]
 
+[[package]]
+name = "find-msvc-tools"
+version = "0.1.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5baebc0774151f905a1a2cc41989300b1e6fbb29aff0ceffa1064fdd3088d582"
+
 [[package]]
 name = "form_urlencoded"
 version = "1.2.2"
@@ -412,6 +428,12 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "shlex"
+version = "1.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0fda2ff0d084019ba4d7c6f371c95d8fd75ce3524c3cb8fb653a3023f6323e64"
+
 [[package]]
 name = "signal-hook-registry"
 version = "1.4.8"
@@ -548,6 +570,7 @@ name = "vectordb"
 version = "0.1.0"
 dependencies = [
  "axum",
+ "cc",
  "serde",
  "tokio",
 ]
diff --git a/Cargo.toml b/Cargo.toml
index 6165d87..ebcece7 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,3 +7,6 @@ edition = "2021"
 axum = "0.8"
 serde = { version = "1", features = ["derive"] }
 tokio = { version = "1", features = ["full"] }
+
+[build-dependencies]
+cc = "1"
diff --git a/build.rs b/build.rs
new file mode 100644
index 0000000..33265f1
--- /dev/null
+++ b/build.rs
@@ -0,0 +1,8 @@
+fn main() {
+    cc::Build::new()
+        .cpp(true)
+        .file("native/src/vector_engine_ffi.cpp")
+        .include("native/include")
+        .std("c++17")
+        .compile("vector_engine_ffi");
+}
diff --git a/native/include/vector_engine_ffi.h b/native/include/vector_engine_ffi.h
new file mode 100644
index 0000000..f1996df
--- /dev/null
+++ b/native/include/vector_engine_ffi.h
@@ -0,0 +1,13 @@
+#ifndef VECTOR_ENGINE_FFI_H
+#define VECTOR_ENGINE_FFI_H
+
+struct NativeVectorEngine;
+
+extern "C" {
+
+NativeVectorEngine* native_vector_engine_new();
+void native_vector_engine_free(NativeVectorEngine* engine);
+
+}
+
+#endif
diff --git a/native/src/vector_engine_ffi.cpp b/native/src/vector_engine_ffi.cpp
new file mode 100644
index 0000000..138bfeb
--- /dev/null
+++ b/native/src/vector_engine_ffi.cpp
@@ -0,0 +1,11 @@
+#include "vector_engine_ffi.h"
+
+struct NativeVectorEngine {};
+
+extern "C" NativeVectorEngine* native_vector_engine_new() {
+    return new NativeVectorEngine();
+}
+
+extern "C" void native_vector_engine_free(NativeVectorEngine* engine) {
+    delete engine;
+}