Much work

src/proto/state.rs

@@ -0,0 +1,72 @@
+use ConnectionError;
+
+/// Represents the state of an H2 stream
+///
+/// ```not_rust
+///                              +--------+
+///                      send PP |        | recv PP
+///                     ,--------|  idle  |--------.
+///                    /         |        |         \
+///                   v          +--------+          v
+///            +----------+          |           +----------+
+///            |          |          | send H /  |          |
+///     ,------| reserved |          | recv H    | reserved |------.
+///     |      | (local)  |          |           | (remote) |      |
+///     |      +----------+          v           +----------+      |
+///     |          |             +--------+             |          |
+///     |          |     recv ES |        | send ES     |          |
+///     |   send H |     ,-------|  open  |-------.     | recv H   |
+///     |          |    /        |        |        \    |          |
+///     |          v   v         +--------+         v   v          |
+///     |      +----------+          |           +----------+      |
+///     |      |   half   |          |           |   half   |      |
+///     |      |  closed  |          | send R /  |  closed  |      |
+///     |      | (remote) |          | recv R    | (local)  |      |
+///     |      +----------+          |           +----------+      |
+///     |           |                |                 |           |
+///     |           | send ES /      |       recv ES / |           |
+///     |           | send R /       v        send R / |           |
+///     |           | recv R     +--------+   recv R   |           |
+///     | send R /  `----------->|        |<-----------'  send R / |
+///     | recv R                 | closed |               recv R   |
+///     `----------------------->|        |<----------------------'
+///                              +--------+
+///
+///        send:   endpoint sends this frame
+///        recv:   endpoint receives this frame
+///
+///        H:  HEADERS frame (with implied CONTINUATIONs)
+///        PP: PUSH_PROMISE frame (with implied CONTINUATIONs)
+///        ES: END_STREAM flag
+///        R:  RST_STREAM frame
+/// ```
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+pub enum State {
+    Idle,
+    ReservedLocal,
+    ReservedRemote,
+    Open,
+    HalfClosedLocal,
+    HalfClosedRemote,
+    Closed,
+}
+
+impl State {
+    /// Transition the state to represent headers being sent.
+    ///
+    /// Returns an error if this is an invalid state transition.
+    pub fn send_headers(&mut self) -> Result<(), ConnectionError> {
+        if *self != State::Idle {
+            unimplemented!();
+        }
+
+        *self = State::Open;
+        Ok(())
+    }
+}
+
+impl Default for State {
+    fn default() -> State {
+        State::Idle
+    }
+}