refactor: use resourceForReadableStream for fetch (#20217)

Switch `ext/fetch` over to `resourceForReadableStream` to simplify and
unify implementation with `ext/serve`. This allows us to work in Rust
with resources only.

Two additional changes made to `resourceForReadableStream` were
required:

- Add an optional length to `resourceForReadableStream` which translates
to `size_hint`
 - Fix a bug where writing to a closed stream that was full would panic

1 files changed, 32 insertions, 1 deletions

diff --git a/ext/web/stream_resource.rs b/ext/web/stream_resource.rs
index 93d10f806..8505be01a 100644
--- a/ext/web/stream_resource.rs
+++ b/ext/web/stream_resource.rs
@@ -197,7 +197,14 @@ impl BoundedBufferChannelInner {
   pub fn write(&mut self, buffer: V8Slice<u8>) -> Result<(), V8Slice<u8>> {
     let next_producer_index = (self.ring_producer + 1) % BUFFER_CHANNEL_SIZE;
     if next_producer_index == self.ring_consumer {
-      return Err(buffer);
+      // Note that we may have been allowed to write because of a close/error condition, but the
+      // underlying channel is actually closed. If this is the case, we return `Ok(())`` and just
+      // drop the bytes on the floor.
+      return if self.closed || self.error.is_some() {
+        Ok(())
+      } else {
+        Err(buffer)
+      };
     }
 
     self.current_size += buffer.len();
@@ -336,6 +343,7 @@ struct ReadableStreamResource {
   channel: BoundedBufferChannel,
   cancel_handle: CancelHandle,
   data: ReadableStreamResourceData,
+  size_hint: (u64, Option<u64>),
 }
 
 impl ReadableStreamResource {
@@ -378,6 +386,10 @@ impl Resource for ReadableStreamResource {
   fn close(self: Rc<Self>) {
     self.close_channel();
   }
+
+  fn size_hint(&self) -> (u64, Option<u64>) {
+    self.size_hint
+  }
 }
 
 impl Drop for ReadableStreamResource {
@@ -438,6 +450,25 @@ pub fn op_readable_stream_resource_allocate(state: &mut OpState) -> ResourceId {
     cancel_handle: Default::default(),
     channel: BoundedBufferChannel::default(),
     data: ReadableStreamResourceData { completion },
+    size_hint: (0, None),
+  };
+  state.resource_table.add(resource)
+}
+
+/// Allocate a resource that wraps a ReadableStream, with a size hint.
+#[op2(fast)]
+#[smi]
+pub fn op_readable_stream_resource_allocate_sized(
+  state: &mut OpState,
+  #[number] length: u64,
+) -> ResourceId {
+  let completion = CompletionHandle::default();
+  let resource = ReadableStreamResource {
+    read_queue: Default::default(),
+    cancel_handle: Default::default(),
+    channel: BoundedBufferChannel::default(),
+    data: ReadableStreamResourceData { completion },
+    size_hint: (length, Some(length)),
   };
   state.resource_table.add(resource)
 }