feat(ext/ffi): add support for buffer arguments (#12335)

This commit adds support for passing buffer arguments across 
FFI boundary.


Co-authored-by: eliassjogreen <eliassjogreen1@gmail.com>
Co-authored-by: Bert Belder <bertbelder@gmail.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/test_ffi/src/lib.rs b/test_ffi/src/lib.rs
index c91d05e05..cc6063ca3 100644
--- a/test_ffi/src/lib.rs
+++ b/test_ffi/src/lib.rs
@@ -1,3 +1,5 @@
+// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
+
 use std::thread::sleep;
 use std::time::Duration;
 
@@ -6,6 +8,13 @@ pub extern "C" fn print_something() {
   println!("something");
 }
 
+#[allow(clippy::not_unsafe_ptr_arg_deref)]
+#[no_mangle]
+pub extern "C" fn print_buffer(ptr: *const u8, len: usize) {
+  let buf = unsafe { std::slice::from_raw_parts(ptr, len) };
+  println!("{:?}", buf);
+}
+
 #[no_mangle]
 pub extern "C" fn add_u32(a: u32, b: u32) -> u32 {
   a + b
@@ -51,3 +60,10 @@ pub extern "C" fn sleep_blocking(ms: u64) {
   let duration = Duration::from_millis(ms);
   sleep(duration);
 }
+
+#[allow(clippy::not_unsafe_ptr_arg_deref)]
+#[no_mangle]
+pub extern "C" fn nonblocking_buffer(ptr: *const u8, len: usize) {
+  let buf = unsafe { std::slice::from_raw_parts(ptr, len) };
+  assert_eq!(buf, vec![1, 2, 3, 4, 5, 6, 7, 8]);
+}