From 21aa8179646c830d262f086a4f9c5234b6f05656 Mon Sep 17 00:00:00 2001
From: Amos Wenger <amos@bearcove.net>
Date: Sat, 1 Jun 2024 23:14:24 +0200
Subject: [PATCH] Section 5.3

---
 crates/httpwg-macros/src/lib.rs               | 21 +++++++
 crates/httpwg/src/lib.rs                      | 27 +++++++++
 .../src/rfc9113/_5_3_1_stream_dependencies.rs | 59 +++++++++++++++++++
 crates/httpwg/src/rfc9113/mod.rs              |  2 +
 4 files changed, 109 insertions(+)
 create mode 100644 crates/httpwg/src/rfc9113/_5_3_1_stream_dependencies.rs

diff --git a/crates/httpwg-macros/src/lib.rs b/crates/httpwg-macros/src/lib.rs
index ed3c71a7..3ec12a25 100644
--- a/crates/httpwg-macros/src/lib.rs
+++ b/crates/httpwg-macros/src/lib.rs
@@ -310,6 +310,27 @@ macro_rules! tests {
                     $body
                 }
             }
+
+            /// Section 5.3: Stream Dependencies
+            mod _5_3_1_stream_dependencies {
+                use super::__suite::_5_3_1_stream_dependencies as __group;
+
+                /// A stream cannot depend on itself. An endpoint MUST treat this
+                /// as a stream error (Section 5.4.2) of type PROTOCOL_ERROR.
+                #[test]
+                fn headers_frame_depends_on_itself() {
+                    use __group::headers_frame_depends_on_itself as test;
+                    $body
+                }
+
+                /// A stream cannot depend on itself. An endpoint MUST treat this
+                /// as a stream error (Section 5.4.2) of type PROTOCOL_ERROR.
+                #[test]
+                fn priority_frame_depends_on_itself() {
+                    use __group::priority_frame_depends_on_itself as test;
+                    $body
+                }
+            }
         }
     };
 }
diff --git a/crates/httpwg/src/lib.rs b/crates/httpwg/src/lib.rs
index 9b67e57f..2c7632c3 100644
--- a/crates/httpwg/src/lib.rs
+++ b/crates/httpwg/src/lib.rs
@@ -645,6 +645,33 @@ impl<IO: IntoHalves> Conn<IO> {
         Ok(())
     }
 
+    pub async fn write_headers_with_priority(
+        &mut self,
+        stream_id: StreamId,
+        flags: impl Into<BitFlags<HeadersFlags>>,
+        priority_spec: PrioritySpec,
+        block_fragment: Piece,
+    ) -> eyre::Result<()> {
+        let flags = flags.into() | HeadersFlags::Priority;
+        let frame = Frame::new(FrameType::Headers(flags), stream_id);
+
+        let payload = block_fragment.into_piece(&mut self.scratch)?;
+        let frame = frame.with_len(payload.len().try_into().unwrap());
+
+        let priority_spec_piece = priority_spec.into_piece(&mut self.scratch)?;
+
+        let header = frame.into_piece(&mut self.scratch)?;
+        self.w
+            .writev_all_owned(
+                PieceList::single(header)
+                    .followed_by(priority_spec_piece)
+                    .followed_by(payload),
+            )
+            .await?;
+
+        Ok(())
+    }
+
     pub async fn write_continuation(
         &mut self,
         stream_id: StreamId,
diff --git a/crates/httpwg/src/rfc9113/_5_3_1_stream_dependencies.rs b/crates/httpwg/src/rfc9113/_5_3_1_stream_dependencies.rs
new file mode 100644
index 00000000..3896f380
--- /dev/null
+++ b/crates/httpwg/src/rfc9113/_5_3_1_stream_dependencies.rs
@@ -0,0 +1,59 @@
+//! Section 5.3: Stream Dependencies
+
+use fluke_buffet::IntoHalves;
+use fluke_h2_parse::{HeadersFlags, PrioritySpec, StreamId};
+
+use crate::{Conn, ErrorC};
+
+/// A stream cannot depend on itself. An endpoint MUST treat this
+/// as a stream error (Section 5.4.2) of type PROTOCOL_ERROR.
+pub async fn headers_frame_depends_on_itself<IO: IntoHalves + 'static>(
+    mut conn: Conn<IO>,
+) -> eyre::Result<()> {
+    let stream_id = StreamId(1);
+
+    conn.handshake().await?;
+
+    let headers = conn.common_headers();
+    let block_fragment = conn.encode_headers(&headers)?;
+
+    conn.write_headers_with_priority(
+        stream_id,
+        HeadersFlags::EndHeaders | HeadersFlags::EndStream,
+        PrioritySpec {
+            stream_dependency: stream_id,
+            exclusive: false,
+            weight: 255,
+        },
+        block_fragment,
+    )
+    .await?;
+
+    conn.verify_stream_error(ErrorC::ProtocolError).await?;
+
+    Ok(())
+}
+
+/// A stream cannot depend on itself. An endpoint MUST treat this
+/// as a stream error (Section 5.4.2) of type PROTOCOL_ERROR.
+pub async fn priority_frame_depends_on_itself<IO: IntoHalves + 'static>(
+    mut conn: Conn<IO>,
+) -> eyre::Result<()> {
+    let stream_id = StreamId(1);
+
+    conn.handshake().await?;
+
+    conn.write_priority(
+        stream_id,
+        PrioritySpec {
+            stream_dependency: stream_id,
+            exclusive: false,
+            weight: 255,
+        },
+    )
+    .await?;
+
+    conn.verify_stream_error(ErrorC::ProtocolError).await?;
+
+    Ok(())
+}
diff --git a/crates/httpwg/src/rfc9113/mod.rs b/crates/httpwg/src/rfc9113/mod.rs
index c6b6af79..74b1f45e 100644
--- a/crates/httpwg/src/rfc9113/mod.rs
+++ b/crates/httpwg/src/rfc9113/mod.rs
@@ -32,3 +32,5 @@ pub mod _4_3_header_compression_and_decompression;
 pub mod _5_1_1_stream_identifiers;
 pub mod _5_1_2_stream_concurrency;
 pub mod _5_1_stream_states;
+
+pub mod _5_3_1_stream_dependencies;