feat(napi): implement create_buffer_copy

README.md

@@ -156,7 +156,7 @@ yarn test
 | [napi_create_array_with_length](https://nodejs.org/api/n-api.html#n_api_napi_create_array_with_length)       | 1            | v8.0.0               | ✅     |
 | [napi_create_arraybuffer](https://nodejs.org/api/n-api.html#n_api_napi_create_arraybuffer)                   | 1            | v8.0.0               | ✅     |
 | [napi_create_buffer](https://nodejs.org/api/n-api.html#n_api_napi_create_buffer)                             | 1            | v8.0.0               | ✅     |
-| [napi_create_buffer_copy](https://nodejs.org/api/n-api.html#n_api_napi_create_buffer_copy)                   | 1            | v8.0.0               | ⛔️    |
+| [napi_create_buffer_copy](https://nodejs.org/api/n-api.html#n_api_napi_create_buffer_copy)                   | 1            | v8.0.0               | ✅     |
 | [napi_create_date](https://nodejs.org/api/n-api.html#n_api_napi_create_date)                                 | 5            | v11.11.0             | ✅     |
 | [napi_create_external](https://nodejs.org/api/n-api.html#n_api_napi_create_external)                         | 1            | v8.0.0               | ✅     |
 | [napi_create_external_arraybuffer](https://nodejs.org/api/n-api.html#n_api_napi_create_external_arraybuffer) | 1            | v8.0.0               | ✅     |

napi/src/env.rs

@@ -267,6 +267,33 @@ impl Env {
     ))
   }
 
+  pub fn create_buffer_copy<D>(&self, data_to_copy: D) -> Result<JsBufferValue>
+  where
+    D: AsRef<[u8]>,
+  {
+    let length = data_to_copy.as_ref().len();
+    let data_ptr = data_to_copy.as_ref().as_ptr();
+    let mut copy_data = ptr::null_mut();
+    let mut raw_value = ptr::null_mut();
+    check_status(unsafe {
+      sys::napi_create_buffer_copy(
+        self.0,
+        length as u64,
+        data_ptr as *mut c_void,
+        &mut copy_data,
+        &mut raw_value,
+      )
+    })?;
+    Ok(JsBufferValue::new(
+      JsBuffer(Value {
+        env: self.0,
+        value: raw_value,
+        value_type: ValueType::Object,
+      }),
+      unsafe { Vec::from_raw_parts(copy_data as *mut u8, length, length) },
+    ))
+  }
+
   pub fn create_arraybuffer(&self, length: u64) -> Result<JsArrayBufferValue> {
     let mut raw_value = ptr::null_mut();
     let mut data: Vec<u8> = Vec::with_capacity(length as usize);

test_module/__test__/buffer.spec.ts

@@ -11,3 +11,10 @@ test('should stringify buffer', (t) => {
   const fixture = 'wow, hello'
   t.is(bindings.bufferToString(Buffer.from(fixture)), fixture)
 })
+
+test('should copy', (t) => {
+  const fixture = Buffer.from('wow, hello')
+  const copyBuffer = bindings.copyBuffer(fixture)
+  t.deepEqual(copyBuffer, fixture)
+  t.not(fixture, copyBuffer)
+})

test_module/src/buffer.rs

@@ -16,8 +16,15 @@ pub fn buffer_to_string(ctx: CallContext) -> Result<JsString> {
   )
 }
 
+#[js_function(1)]
+pub fn copy_buffer(ctx: CallContext) -> Result<JsBuffer> {
+  let buffer = ctx.get::<JsBuffer>(0)?.into_value()?;
+  ctx.env.create_buffer_copy(buffer).map(|b| b.into_raw())
+}
+
 pub fn register_js(module: &mut Module) -> Result<()> {
   module.create_named_method("getBufferLength", get_buffer_length)?;
   module.create_named_method("bufferToString", buffer_to_string)?;
+  module.create_named_method("copyBuffer", copy_buffer)?;
   Ok(())
 }