initial commit

src/lib.rs

@@ -0,0 +1,42 @@
+use std::mem;
+use std::slice;
+use std::str;
+
+use cel::{Context, ExecutionError, Program, Value};
+
+#[unsafe(no_mangle)]
+pub extern "C" fn allocation(n: usize) -> *mut u8 {
+    mem::ManuallyDrop::new(Vec::with_capacity(n)).as_mut_ptr()
+}
+
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn evaluate(s: *const u8) -> *mut u8 {
+    unsafe {
+        let length = u32::from_le_bytes(*(s as *const [u8; 4])) as usize;
+        let input = slice::from_raw_parts(s.offset(4), length);
+        let output = evaluate_buffers(input);
+        mem::ManuallyDrop::new(output).as_mut_ptr()
+    }
+}
+
+fn evaluate_buffers(input: &[u8]) -> Vec<u8> {
+    let contents = str::from_utf8(input).unwrap();
+    let result = evaluate_cel(contents);
+    let success = result.is_ok();
+    let message = result.unwrap_or_else(|e| e.to_string());
+    let len = message.len();
+    let mut buffer = Vec::with_capacity(len + 8);
+    buffer.push(if success { 1 } else { 0 });
+    buffer.extend(vec![0; 3]);
+    buffer.extend_from_slice(&(len as u32).to_le_bytes());
+    buffer.extend_from_slice(message.as_bytes());
+    buffer
+}
+
+fn evaluate_cel(content: &str) -> Result<String, ExecutionError> {
+    let program = Program::compile(content).unwrap();
+    let mut context = Context::default();
+    // context.add_function("add", |a: i64, b: i64| a + b);
+    let value = program.execute(&context)?;
+    Ok(format!("{:?}", value))
+}