feat(native): rename crate and update build scripts

Author: zah

Justfile

@@ -5,3 +5,6 @@ test:
 
 bench name="heavy_work":
     ruby test/benchmarks/run_benchmark.rb {{name}}
+
+build-extension:
+    cargo build --release --manifest-path ext/native_tracer/Cargo.toml

ext/native_tracer/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "codetracer_ruby_native_recoreder"
+version = "0.1.0"
+edition = "2021" # latest stable Rust edition
+description = "Native Ruby tracer using rb_add_event_hook2"
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+rb-sys = "0.9"
+runtime_tracing = "0.1"

ext/native_tracer/README.md

@@ -0,0 +1,24 @@
+# codetracer_ruby_native_recoreder
+
+This crate provides a minimal Ruby tracer implemented in Rust.
+It registers a Ruby VM event hook using `rb_add_event_hook2` and
+records basic information for each executed line.
+
+Recorded events are written using the [`runtime_tracing`](https://github.com/metacraft-labs/runtime_tracing) crate.
+
+## Building
+
+```
+cargo build --release
+```
+
+If you have `just` installed, run `just build-extension` from the project root.
+
+The produced shared library can be required from Ruby:
+
+```ruby
+require_relative 'target/release/libcodetracer_ruby_native_recoreder'
+```
+
+Once loaded, the tracer starts writing a trace to `trace.json` or the
+path specified via the `CODETRACER_DB_TRACE_PATH` environment variable.

ext/native_tracer/src/lib.rs

@@ -0,0 +1,33 @@
+use std::ffi::CStr;
+use std::os::raw::{c_char, c_int};
+use rb_sys::{VALUE, ID, rb_add_event_hook2, rb_event_flag_t, RUBY_EVENT_LINE, rb_sourcefile, rb_sourceline, RUBY_EVENT_HOOK_FLAG_RAW_ARG};
+use runtime_tracing::{TraceWriter, StepRecord};
+
+static mut WRITER: Option<TraceWriter<std::fs::File>> = None;
+
+extern "C" fn event_hook(ev: rb_event_flag_t, _data: VALUE, _self: VALUE, _mid: ID, _klass: VALUE) {
+    if ev & RUBY_EVENT_LINE as rb_event_flag_t != 0 {
+        unsafe {
+            if let Some(writer) = WRITER.as_mut() {
+                let line: u32 = rb_sourceline() as u32;
+                let file_ptr: *const c_char = rb_sourcefile();
+                if !file_ptr.is_null() {
+                    if let Ok(path) = CStr::from_ptr(file_ptr).to_str() {
+                        let rec = StepRecord { path: path.into(), line };
+                        let _ = writer.write_step(&rec);
+                    }
+                }
+            }
+        }
+    }
+}
+
+#[no_mangle]
+pub extern "C" fn Init_codetracer_ruby_native_recoreder() {
+    unsafe {
+        let out = std::env::var("CODETRACER_DB_TRACE_PATH").unwrap_or_else(|_| "trace.json".to_string());
+        let file = std::fs::File::create(out).expect("failed to create trace output");
+        WRITER = Some(TraceWriter::new(file));
+        rb_add_event_hook2(Some(event_hook), RUBY_EVENT_LINE as rb_event_flag_t, 0 as VALUE, RUBY_EVENT_HOOK_FLAG_RAW_ARG as i32);
+    }
+}

flake.nix

@@ -12,7 +12,7 @@
         let pkgs = import nixpkgs { inherit system; };
         in {
           default = pkgs.mkShell {
-            packages = with pkgs; [ ruby just git-lfs ];
+            packages = with pkgs; [ ruby rustc cargo just git-lfs ];
           };
         });
     };