From 6cdb55ed6200bc7e02d35e596f3a8a85a6adf5eb Mon Sep 17 00:00:00 2001
From: Andy Finch <andyfinch7@gmail.com>
Date: Wed, 25 Dec 2019 20:37:25 -0500
Subject: [PATCH] add v8::Uint8Array (#133)

---
 src/binding.cc     |  4 ++++
 src/lib.rs         |  2 ++
 src/uint8_array.rs | 29 +++++++++++++++++++++++++++++
 tests/test_api.rs  | 40 +++++++++++++++++++++++++++++++++++++++-
 4 files changed, 74 insertions(+), 1 deletion(-)
 create mode 100644 src/uint8_array.rs

diff --git a/src/binding.cc b/src/binding.cc
index ba7bb1c9..221d5c09 100644
--- a/src/binding.cc
+++ b/src/binding.cc
@@ -546,6 +546,10 @@ void v8__TryCatch__SetCaptureMessage(v8::TryCatch& self, bool value) {
   self.SetCaptureMessage(value);
 }
 
+v8::Uint8Array* v8__Uint8Array__New(v8::ArrayBuffer* buf_ptr, size_t byte_offset, size_t length) {
+  return local_to_ptr(v8::Uint8Array::New(ptr_to_local(buf_ptr), byte_offset, length));
+}
+
 v8::Script* v8__Script__Compile(v8::Context* context, v8::String* source,
                                 v8::ScriptOrigin* origin) {
   return maybe_local_to_ptr(
diff --git a/src/lib.rs b/src/lib.rs
index 77f1cde8..0b05d191 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -32,6 +32,7 @@ mod snapshot;
 mod string;
 mod support;
 mod try_catch;
+mod uint8_array;
 mod value;
 
 pub mod array_buffer_view;
@@ -75,4 +76,5 @@ pub use string::String;
 pub use support::MaybeBool;
 pub use support::UniqueRef;
 pub use try_catch::{TryCatch, TryCatchScope};
+pub use uint8_array::Uint8Array;
 pub use value::Value;
diff --git a/src/uint8_array.rs b/src/uint8_array.rs
new file mode 100644
index 00000000..7f83910e
--- /dev/null
+++ b/src/uint8_array.rs
@@ -0,0 +1,29 @@
+use std::ops::DerefMut;
+
+use crate::support::Opaque;
+use crate::ArrayBuffer;
+use crate::Local;
+
+extern "C" {
+  fn v8__Uint8Array__New(
+    buf: *mut ArrayBuffer,
+    byte_offset: usize,
+    length: usize,
+  ) -> *mut Uint8Array;
+}
+
+/// An instance of Uint8Array constructor (ES6 draft 15.13.6).
+#[repr(C)]
+pub struct Uint8Array(Opaque);
+
+impl Uint8Array {
+  pub fn new<'sc>(
+    mut buf: Local<ArrayBuffer>,
+    byte_offset: usize,
+    length: usize,
+  ) -> Option<Local<'sc, Uint8Array>> {
+    unsafe {
+      Local::from_raw(v8__Uint8Array__New(buf.deref_mut(), byte_offset, length))
+    }
+  }
+}
diff --git a/tests/test_api.rs b/tests/test_api.rs
index 7374f6ea..0c156e2d 100644
--- a/tests/test_api.rs
+++ b/tests/test_api.rs
@@ -1191,7 +1191,7 @@ fn array_buffer_view() {
     let result = script.run(s, context).unwrap();
     // TODO: safer casts.
     let result: v8::Local<v8::array_buffer_view::ArrayBufferView> =
-      unsafe { std::mem::transmute_copy(&result) };
+      cast(result);
     assert_eq!(result.byte_length(), 4);
     assert_eq!(result.byte_offset(), 0);
     let mut dest = [0; 4];
@@ -1267,3 +1267,41 @@ fn snapshot_creator() {
 
   drop(g);
 }
+
+#[test]
+fn uint8_array() {
+  let g = setup();
+  let mut params = v8::Isolate::create_params();
+  params.set_array_buffer_allocator(v8::new_default_allocator());
+  let mut isolate = v8::Isolate::new(params);
+  isolate.enter();
+  let mut locker = v8::Locker::new(&isolate);
+  {
+    let mut hs = v8::HandleScope::new(&mut locker);
+    let s = hs.enter();
+    let mut context = v8::Context::new(s);
+    context.enter();
+    let source = v8::String::new(s, "new Uint8Array([23,23,23,23])").unwrap();
+    let mut script = v8::Script::compile(s, context, source, None).unwrap();
+    source.to_rust_string_lossy(s);
+    let result = script.run(s, context).unwrap();
+    // TODO: safer casts.
+    let result: v8::Local<v8::array_buffer_view::ArrayBufferView> =
+      cast(result);
+    assert_eq!(result.byte_length(), 4);
+    assert_eq!(result.byte_offset(), 0);
+    let mut dest = [0; 4];
+    let copy_bytes = result.copy_contents(&mut dest);
+    assert_eq!(copy_bytes, 4);
+    assert_eq!(dest, [23, 23, 23, 23]);
+    let maybe_ab = result.buffer();
+    assert!(maybe_ab.is_some());
+    let ab = maybe_ab.unwrap();
+    let uint8_array = v8::Uint8Array::new(ab, 0, 0);
+    assert!(uint8_array.is_some());
+    context.exit();
+  }
+  drop(locker);
+  isolate.exit();
+  drop(g);
+}