From bd7809cc1825e8836410b8ee4f9187e61d1a2508 Mon Sep 17 00:00:00 2001
From: Matthew Olsson <matthewcolsson@gmail.com>
Date: Sat, 8 Apr 2023 11:49:58 -0700
Subject: [PATCH] LibWeb: Mostly implement
 ReadableByteStreamController.[[ReleaseSteps]]

---
 .../Streams/ReadableByteStreamController.cpp  | 21 +++++++++++++++++++
 .../Streams/ReadableByteStreamController.h    |  1 +
 2 files changed, 22 insertions(+)

diff --git a/Userland/Libraries/LibWeb/Streams/ReadableByteStreamController.cpp b/Userland/Libraries/LibWeb/Streams/ReadableByteStreamController.cpp
index 1bca783d7ab..56b0d19e8c1 100644
--- a/Userland/Libraries/LibWeb/Streams/ReadableByteStreamController.cpp
+++ b/Userland/Libraries/LibWeb/Streams/ReadableByteStreamController.cpp
@@ -106,6 +106,27 @@ WebIDL::ExceptionOr<void> ReadableByteStreamController::pull_steps(NonnullRefPtr
     return {};
 }
 
+// https://streams.spec.whatwg.org/#rbs-controller-private-pull
+WebIDL::ExceptionOr<void> ReadableByteStreamController::release_steps()
+{
+    auto& vm = this->vm();
+
+    // 1. If this.[[pendingPullIntos]] is not empty,
+    if (!m_pending_pull_intos.is_empty()) {
+        // 1. Let firstPendingPullInto be this.[[pendingPullIntos]][0].
+        auto first_pending_pull_into = m_pending_pull_intos.first();
+
+        // 2. Set firstPendingPullInto’s reader type to "none".
+        first_pending_pull_into.reader_type = ReaderType::None;
+
+        // 3. Set this.[[pendingPullIntos]] to the list « firstPendingPullInto ».
+        m_pending_pull_intos.clear();
+        TRY_OR_THROW_OOM(vm, m_pending_pull_intos.try_append(first_pending_pull_into));
+    }
+
+    return {};
+}
+
 void ReadableByteStreamController::visit_edges(Cell::Visitor& visitor)
 {
     Base::visit_edges(visitor);
diff --git a/Userland/Libraries/LibWeb/Streams/ReadableByteStreamController.h b/Userland/Libraries/LibWeb/Streams/ReadableByteStreamController.h
index a55905249f9..ca16d3190a6 100644
--- a/Userland/Libraries/LibWeb/Streams/ReadableByteStreamController.h
+++ b/Userland/Libraries/LibWeb/Streams/ReadableByteStreamController.h
@@ -118,6 +118,7 @@ public:
 
     WebIDL::ExceptionOr<JS::GCPtr<WebIDL::Promise>> cancel_steps(JS::Value reason);
     WebIDL::ExceptionOr<void> pull_steps(NonnullRefPtr<ReadRequest>);
+    WebIDL::ExceptionOr<void> release_steps();
 
 private:
     explicit ReadableByteStreamController(JS::Realm&);