From 961a4940b5cd55dc808e70bb9998650b0c9d502b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bartek=20Iwa=C5=84czuk?= <biwanczuk@gmail.com>
Date: Sun, 8 Jan 2023 15:11:19 +0100
Subject: [PATCH] feat: Add v8::TypedArray::length (#1166)

---
 src/binding.cc     |  3 +++
 src/typed_array.rs |  8 ++++++++
 tests/test_api.rs  | 11 +++++++++++
 3 files changed, 22 insertions(+)

diff --git a/src/binding.cc b/src/binding.cc
index 3cd54efb..8a6ee379 100644
--- a/src/binding.cc
+++ b/src/binding.cc
@@ -463,6 +463,9 @@ uint32_t v8__ScriptCompiler__CachedDataVersionTag() {
   return v8::ScriptCompiler::CachedDataVersionTag();
 }
 
+size_t v8__TypedArray__Length(const v8::TypedArray* self) { 
+  return ptr_to_local(self)->Length(); 
+}
 size_t v8__TypedArray__kMaxLength() { return v8::TypedArray::kMaxLength; }
 
 bool v8__Data__EQ(const v8::Data& self, const v8::Data& other) {
diff --git a/src/typed_array.rs b/src/typed_array.rs
index 7d50effb..97a4cbfc 100644
--- a/src/typed_array.rs
+++ b/src/typed_array.rs
@@ -7,6 +7,7 @@ use crate::TypedArray;
 
 extern "C" {
   fn v8__TypedArray__kMaxLength() -> size_t;
+  fn v8__TypedArray__Length(this: *const TypedArray) -> size_t;
 }
 
 impl TypedArray {
@@ -17,6 +18,13 @@ impl TypedArray {
   pub fn max_length() -> usize {
     unsafe { v8__TypedArray__kMaxLength() }
   }
+
+  /// Number of elements in this typed array
+  /// (e.g. for Int16Array, |ByteLength|/2).
+  #[inline(always)]
+  pub fn length(&self) -> usize {
+    unsafe { v8__TypedArray__Length(self) }
+  }
 }
 
 macro_rules! typed_array {
diff --git a/tests/test_api.rs b/tests/test_api.rs
index ad11f6fa..0735912c 100644
--- a/tests/test_api.rs
+++ b/tests/test_api.rs
@@ -4290,36 +4290,47 @@ fn typed_array_constructors() {
 
   let t = v8::Uint8Array::new(scope, ab, 0, 0).unwrap();
   assert!(t.is_uint8_array());
+  assert_eq!(t.length(), 0);
 
   let t = v8::Uint8ClampedArray::new(scope, ab, 0, 0).unwrap();
   assert!(t.is_uint8_clamped_array());
+  assert_eq!(t.length(), 0);
 
   let t = v8::Int8Array::new(scope, ab, 0, 0).unwrap();
   assert!(t.is_int8_array());
+  assert_eq!(t.length(), 0);
 
   let t = v8::Uint16Array::new(scope, ab, 0, 0).unwrap();
   assert!(t.is_uint16_array());
+  assert_eq!(t.length(), 0);
 
   let t = v8::Int16Array::new(scope, ab, 0, 0).unwrap();
   assert!(t.is_int16_array());
+  assert_eq!(t.length(), 0);
 
   let t = v8::Uint32Array::new(scope, ab, 0, 0).unwrap();
   assert!(t.is_uint32_array());
+  assert_eq!(t.length(), 0);
 
   let t = v8::Int32Array::new(scope, ab, 0, 0).unwrap();
   assert!(t.is_int32_array());
+  assert_eq!(t.length(), 0);
 
   let t = v8::Float32Array::new(scope, ab, 0, 0).unwrap();
   assert!(t.is_float32_array());
+  assert_eq!(t.length(), 0);
 
   let t = v8::Float64Array::new(scope, ab, 0, 0).unwrap();
   assert!(t.is_float64_array());
+  assert_eq!(t.length(), 0);
 
   let t = v8::BigUint64Array::new(scope, ab, 0, 0).unwrap();
   assert!(t.is_big_uint64_array());
+  assert_eq!(t.length(), 0);
 
   let t = v8::BigInt64Array::new(scope, ab, 0, 0).unwrap();
   assert!(t.is_big_int64_array());
+  assert_eq!(t.length(), 0);
 
   // TypedArray::max_length() ought to be >= 2^30 < 2^32 in 64 bits
   #[cfg(target_pointer_width = "64")]