From 6547d35fa5a6ae29e25e7592c5b7a06cb8399c1e Mon Sep 17 00:00:00 2001
From: Taym Haddadi <haddadi.taym@gmail.com>
Date: Tue, 4 Feb 2025 12:58:46 +0100
Subject: [PATCH] Script: implement ReadableStreamBYOBRequest (#35074)

* Script: implement ReadableStreamBYOBReader::Read

Signed-off-by: Taym Haddadi <haddadi.taym@gmail.com>

* implement viewed_buffer_array_byte_length and byte_length

Signed-off-by: Taym Haddadi <haddadi.taym@gmail.com>

* Correct BufferSource implemntation

Signed-off-by: Taym Haddadi <haddadi.taym@gmail.com>

* Reduce BufferSource to two variants ArrayBuffer and ArrayBufferView

Signed-off-by: Taym Haddadi <haddadi.taym@gmail.com>

* Scriptt: implement ReadableStreamBYOBRequest

Signed-off-by: Taym Haddadi <haddadi.taym@gmail.com>

* fix is_detached_buffer and viewed_buffer_array_byte_length

Signed-off-by: Taym Haddadi <haddadi.taym@gmail.com>

* Use if let Some instead of unwrap()

Signed-off-by: Taym Haddadi <haddadi.taym@gmail.com>

---------

Signed-off-by: Taym Haddadi <haddadi.taym@gmail.com>
---
 .../dom/readablebytestreamcontroller.rs       | 13 ++++
 .../script/dom/readablestreambyobrequest.rs   | 66 +++++++++++++++----
 2 files changed, 68 insertions(+), 11 deletions(-)

diff --git a/components/script/dom/readablebytestreamcontroller.rs b/components/script/dom/readablebytestreamcontroller.rs
index 8d1c1b91eed..85c2a08fe76 100644
--- a/components/script/dom/readablebytestreamcontroller.rs
+++ b/components/script/dom/readablebytestreamcontroller.rs
@@ -39,6 +39,19 @@ impl ReadableByteStreamController {
     ) {
         todo!()
     }
+
+    /// <https://streams.spec.whatwg.org/#readable-byte-stream-controller-respond>
+    pub(crate) fn respond(&self, _bytes_written: u64) -> Fallible<()> {
+        todo!()
+    }
+
+    /// <https://streams.spec.whatwg.org/#readable-byte-stream-controller-respond-with-new-view>
+    pub(crate) fn respond_with_new_view(
+        &self,
+        _view: HeapBufferSource<ArrayBufferViewU8>,
+    ) -> Fallible<()> {
+        todo!()
+    }
 }
 
 impl ReadableByteStreamControllerMethods<crate::DomTypeHolder> for ReadableByteStreamController {
diff --git a/components/script/dom/readablestreambyobrequest.rs b/components/script/dom/readablestreambyobrequest.rs
index 47df222e1d8..973dede62d9 100644
--- a/components/script/dom/readablestreambyobrequest.rs
+++ b/components/script/dom/readablestreambyobrequest.rs
@@ -3,37 +3,81 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use dom_struct::dom_struct;
+use js::gc::CustomAutoRooterGuard;
+use js::jsapi::Heap;
+use js::typedarray::{ArrayBufferView, ArrayBufferViewU8};
 
+use super::bindings::buffer_source::{BufferSource, HeapBufferSource};
 use crate::dom::bindings::codegen::Bindings::ReadableStreamBYOBRequestBinding::ReadableStreamBYOBRequestMethods;
 use crate::dom::bindings::import::module::{Error, Fallible};
 use crate::dom::bindings::reflector::Reflector;
+use crate::dom::bindings::root::MutNullableDom;
+use crate::dom::readablebytestreamcontroller::ReadableByteStreamController;
+use crate::dom::types::GlobalScope;
 use crate::script_runtime::JSContext as SafeJSContext;
 
 /// <https://streams.spec.whatwg.org/#readablestreambyobrequest>
 #[dom_struct]
 pub(crate) struct ReadableStreamBYOBRequest {
     reflector_: Reflector,
+    controller: MutNullableDom<ReadableByteStreamController>,
+    #[ignore_malloc_size_of = "mozjs"]
+    view: HeapBufferSource<ArrayBufferViewU8>,
 }
 
 impl ReadableStreamBYOBRequestMethods<crate::DomTypeHolder> for ReadableStreamBYOBRequest {
     /// <https://streams.spec.whatwg.org/#rs-byob-request-view>
     fn GetView(&self, _cx: SafeJSContext) -> Option<js::typedarray::ArrayBufferView> {
-        // TODO
-        None
+        // Return this.[[view]].
+        self.view.buffer_to_option()
     }
 
     /// <https://streams.spec.whatwg.org/#rs-byob-request-respond>
-    fn Respond(&self, _bytes_written: u64) -> Fallible<()> {
-        // TODO
-        Err(Error::NotFound)
+    fn Respond(&self, bytes_written: u64) -> Fallible<()> {
+        let cx = GlobalScope::get_cx();
+
+        // If this.[[controller]] is undefined, throw a TypeError exception.
+        let controller = if let Some(controller) = self.controller.get() {
+            controller
+        } else {
+            return Err(Error::Type("controller is undefined".to_owned()));
+        };
+
+        // If ! IsDetachedBuffer(this.[[view]].[[ArrayBuffer]]) is true, throw a TypeError exception.
+        if self.view.is_detached_buffer(cx) {
+            return Err(Error::Type("buffer is detached".to_owned()));
+        }
+
+        // Assert: this.[[view]].[[ByteLength]] > 0.
+        assert!(self.view.byte_length() > 0);
+
+        // Assert: this.[[view]].[[ViewedArrayBuffer]].[[ByteLength]] > 0.
+        assert!(self.view.viewed_buffer_array_byte_length(cx) > 0);
+
+        // Perform ? ReadableByteStreamControllerRespond(this.[[controller]], bytesWritten).
+        controller.respond(bytes_written)
     }
 
     /// <https://streams.spec.whatwg.org/#rs-byob-request-respond-with-new-view>
-    fn RespondWithNewView(
-        &self,
-        _view: js::gc::CustomAutoRooterGuard<js::typedarray::ArrayBufferView>,
-    ) -> Fallible<()> {
-        // TODO
-        Err(Error::NotFound)
+    #[allow(unsafe_code)]
+    fn RespondWithNewView(&self, view: CustomAutoRooterGuard<ArrayBufferView>) -> Fallible<()> {
+        let view = HeapBufferSource::<ArrayBufferViewU8>::new(BufferSource::ArrayBufferView(
+            Heap::boxed(unsafe { *view.underlying_object() }),
+        ));
+
+        // If this.[[controller]] is undefined, throw a TypeError exception.
+        let controller = if let Some(controller) = self.controller.get() {
+            controller
+        } else {
+            return Err(Error::Type("controller is undefined".to_owned()));
+        };
+
+        // If ! IsDetachedBuffer(view.[[ViewedArrayBuffer]]) is true, throw a TypeError exception.
+        if self.view.is_detached_buffer(GlobalScope::get_cx()) {
+            return Err(Error::Type("buffer is detached".to_owned()));
+        }
+
+        // Return ? ReadableByteStreamControllerRespondWithNewView(this.[[controller]], view).
+        controller.respond_with_new_view(view)
     }
 }