feat(npm): implement Node API (#13633)

This PR implements the NAPI for loading native modules into Deno. 

Co-authored-by: Bartek Iwańczuk <biwanczuk@gmail.com>
Co-authored-by: DjDeveloper <43033058+DjDeveloperr@users.noreply.github.com>
Co-authored-by: Ryan Dahl <ry@tinyclouds.org>

1 files changed, 23 insertions, 0 deletions

diff --git a/cli/napi/util.rs b/cli/napi/util.rs
new file mode 100644
index 000000000..2dea03554
--- /dev/null
+++ b/cli/napi/util.rs
@@ -0,0 +1,23 @@
+// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
+
+use deno_runtime::deno_napi::*;
+use std::cell::Cell;
+
+unsafe fn get_backing_store_slice(
+  backing_store: &mut v8::SharedRef<v8::BackingStore>,
+  byte_offset: usize,
+  byte_length: usize,
+) -> &mut [u8] {
+  let cells: *const [Cell<u8>] =
+    &backing_store[byte_offset..byte_offset + byte_length];
+  let mut bytes = cells as *mut [u8];
+  &mut *bytes
+}
+
+pub fn get_array_buffer_ptr(ab: v8::Local<v8::ArrayBuffer>) -> *mut u8 {
+  let mut backing_store = ab.get_backing_store();
+  let byte_length = ab.byte_length();
+  let mut slice =
+    unsafe { get_backing_store_slice(&mut backing_store, 0, byte_length) };
+  slice.as_mut_ptr()
+}