Move to custom stream storage

src/proto/streams/store.rs

@@ -0,0 +1,81 @@
+extern crate slab;
+
+use proto::*;
+
+use std::collections::{HashMap, hash_map};
+
+/// Storage for streams
+#[derive(Debug)]
+pub struct Store {
+    slab: slab::Slab<state::Stream>,
+    ids: HashMap<StreamId, usize>,
+}
+
+pub enum Entry<'a> {
+    Occupied(OccupiedEntry<'a>),
+    Vacant(VacantEntry<'a>),
+}
+
+pub struct OccupiedEntry<'a> {
+    ids: hash_map::OccupiedEntry<'a, StreamId, usize>,
+    slab: &'a mut slab::Slab<state::Stream>,
+}
+
+pub struct VacantEntry<'a> {
+    ids: hash_map::VacantEntry<'a, StreamId, usize>,
+    slab: &'a mut slab::Slab<state::Stream>,
+}
+
+impl Store {
+    pub fn new() -> Self {
+        Store {
+            slab: slab::Slab::new(),
+            ids: HashMap::new(),
+        }
+    }
+
+    pub fn get_mut(&mut self, id: &StreamId) -> Option<&mut state::Stream> {
+        if let Some(handle) = self.ids.get(id) {
+            Some(&mut self.slab[*handle])
+        } else {
+            None
+        }
+    }
+
+    pub fn entry(&mut self, id: StreamId) -> Entry {
+        use self::hash_map::Entry::*;
+
+        match self.ids.entry(id) {
+            Occupied(e) => {
+                Entry::Occupied(OccupiedEntry {
+                    ids: e,
+                    slab: &mut self.slab,
+                })
+            }
+            Vacant(e) => {
+                Entry::Vacant(VacantEntry {
+                    ids: e,
+                    slab: &mut self.slab,
+                })
+            }
+        }
+    }
+}
+
+impl<'a> OccupiedEntry<'a> {
+    pub fn into_mut(self) -> &'a mut state::Stream {
+        &mut self.slab[*self.ids.get()]
+    }
+}
+
+impl<'a> VacantEntry<'a> {
+    pub fn insert(self, value: state::Stream) -> &'a mut state::Stream {
+        // Insert the value in the slab
+        let handle = self.slab.insert(value);
+
+        // Insert the handle in the ID map
+        self.ids.insert(handle);
+
+        &mut self.slab[handle]
+    }
+}