Sketch is mostly finalized now fill in with code

Cargo.toml

@@ -9,6 +9,7 @@ edition = "2018"
 petgraph = "0.5.1"
 serde = { version = "1.0.114", features = ["derive"] }
 serde_json = "1.0.56"
+maplit = "1.0.2"
 
 [dependencies.ruma]
 git = "https://github.com/ruma/ruma"

src/lib.rs

@@ -16,9 +16,14 @@ mod state_store;
 pub use state_event::StateEvent;
 pub use state_store::StateStore;
 
+// We want to yield to the reactor occasionally during state res when dealing
+// with large data sets, so that we don't exhaust the reactor. This is done by
+// yielding to reactor during loops every N iterations.
+const _YIELD_AFTER_ITERATIONS: usize = 100;
+
 pub enum ResolutionResult {
     Conflicted(Vec<StateMap<EventId>>),
-    Resolved(Vec<StateMap<EventId>>),
+    Resolved(StateMap<EventId>),
 }
 
 /// A mapping of event type and state_key to some value `T`, usually an `EventId`.
@@ -53,15 +58,17 @@ impl StateResolution {
         room_id: &RoomId,
         room_version: &RoomVersionId,
         state_sets: Vec<StateMap<EventId>>,
-        store: &mut dyn StateStore,
+        store: &dyn StateStore,
         // TODO actual error handling (`thiserror`??)
     ) -> Result<ResolutionResult, serde_json::Error> {
         let mut event_map = EventMap::new();
         // split non-conflicting and conflicting state
-        let (clean, mut conflicting) = self.seperate(&state_sets);
+        let (clean, conflicting) = self.seperate(&state_sets);
 
         if conflicting.is_empty() {
-            return Ok(ResolutionResult::Resolved(clean));
+            return Ok(ResolutionResult::Resolved(
+                clean.into_iter().flat_map(|map| map.into_iter()).collect(),
+            ));
         }
 
         // the set of auth events that are not common across server forks
@@ -71,17 +78,18 @@ impl StateResolution {
         auth_diff.extend(conflicting.iter().flat_map(|map| map.values().cloned()));
         let all_conflicted = auth_diff;
 
-        let all_conflicted = conflicting;
+        // TODO get events and add to event_map
+        // TODO throw error if event is not for this room
+        // TODO make sure each conflicting event is in?? event_map `{eid for eid in full_conflicted_set if eid in event_map}`
 
         let power_events = all_conflicted
             .iter()
-            .filter(is_power_event)
-            .flat_map(|map| map.values())
+            .filter(|id| is_power_event(id, store))
             .cloned()
             .collect::<Vec<_>>();
 
         // sort the power events based on power_level/clock/event_id and outgoing/incoming edges
-        let sorted_power_levels = self.revers_topological_power_sort(
+        let mut sorted_power_levels = self.revers_topological_power_sort(
             room_id,
             &power_events,
             &mut event_map,
@@ -93,16 +101,48 @@ impl StateResolution {
         let resolved = self.iterative_auth_check(
             room_id,
             room_version,
-            &power_events,
+            &sorted_power_levels,
             &clean,
             &mut event_map,
             store,
         );
 
+        // At this point the power_events have been resolved we now have to
+        // sort the remaining events using the mainline of the resolved power level.
+
+        sorted_power_levels.dedup();
+        let deduped_power_ev = sorted_power_levels;
+
+        let events_to_resolve = all_conflicted
+            .iter()
+            .filter(|id| deduped_power_ev.contains(id))
+            .cloned()
+            .collect::<Vec<_>>();
+
+        let power_event = resolved.get(&(EventType::RoomPowerLevels, "".into()));
+
+        let sorted_left_events =
+            self.mainline_sort(room_id, &events_to_resolve, power_event, &event_map, store);
+
+        let mut resolved_state = self.iterative_auth_check(
+            room_id,
+            room_version,
+            &sorted_left_events,
+            &[resolved],
+            &mut event_map,
+            store,
+        );
+
+        // add unconflicted state to the resolved state
+        resolved_state.extend(clean.into_iter().flat_map(|map| map.into_iter()));
+
         // TODO return something not a place holder
-        Ok(ResolutionResult::Resolved(vec![]))
+        Ok(ResolutionResult::Resolved(resolved_state))
     }
 
+    /// Split the events that have no conflicts from those that are conflicting.
+    ///
+    /// The tuple looks like `(unconflicted, conflicted)`.
     fn seperate(
         &mut self,
         state_sets: &[StateMap<EventId>],
@@ -115,7 +155,7 @@ impl StateResolution {
         &mut self,
         state_sets: &[StateMap<EventId>],
         event_map: &EventMap<StateEvent>,
-        store: &mut dyn StateStore,
+        store: &dyn StateStore,
     ) -> Result<Vec<EventId>, serde_json::Error> {
         panic!()
     }
@@ -125,9 +165,9 @@ impl StateResolution {
         room_id: &RoomId,
         power_events: &[EventId],
         event_map: &EventMap<StateEvent>,
-        store: &mut dyn StateStore,
-        conflicted_set: &[StateMap<EventId>],
-    ) -> Vec<StateEvent> {
+        store: &dyn StateStore,
+        conflicted_set: &[EventId],
+    ) -> Vec<EventId> {
         panic!()
     }
 
@@ -138,14 +178,125 @@ impl StateResolution {
         power_events: &[EventId],
         unconflicted_state: &[StateMap<EventId>],
         event_map: &EventMap<StateEvent>,
-        store: &mut dyn StateStore,
-    ) -> Vec<StateEvent> {
+        store: &dyn StateStore,
+    ) -> StateMap<EventId> {
         panic!()
     }
+
+    /// Returns the sorted `to_sort` list of `EventId`s based on a mainline sort using
+    /// the `resolved_power_level`.
+    fn mainline_sort(
+        &mut self,
+        room_id: &RoomId,
+        to_sort: &[EventId],
+        resolved_power_level: Option<&EventId>,
+        event_map: &EventMap<StateEvent>,
+        store: &dyn StateStore,
+    ) -> Vec<EventId> {
+        // There can be no EventId's to sort, bail.
+        if to_sort.is_empty() {
+            return vec![];
+        }
+
+        let mut mainline = vec![];
+        let mut pl = resolved_power_level.cloned();
+        let mut idx = 0;
+        while let Some(p) = pl {
+            mainline.push(p.clone());
+            // We don't need the actual pl_ev here since we delegate to the store
+            let auth_events = store.auth_event_ids(room_id, &p).unwrap();
+            pl = None;
+            for aid in auth_events {
+                let ev = store.get_event(&aid).unwrap();
+                if ev.is_type_and_key(EventType::RoomPowerLevels, "") {
+                    pl = Some(aid);
+                    break;
+                }
+            }
+            // We yield occasionally when we're working with large data sets to
+            // ensure that we don't block the reactor loop for too long.
+            if idx != 0 && idx % _YIELD_AFTER_ITERATIONS == 0 {
+                // yield clock.sleep(0)
+            }
+            idx += 1;
+        }
+
+        let mainline_map = mainline
+            .iter()
+            .enumerate()
+            .map(|(idx, eid)| ((*eid).clone(), idx))
+            .collect::<BTreeMap<_, _>>();
+        let mut sort_event_ids = to_sort.to_vec();
+
+        let mut order_map = BTreeMap::new();
+        for (idx, ev_id) in to_sort.iter().enumerate() {
+            let depth = self.get_mainline_depth(
+                room_id,
+                event_map.get(ev_id).cloned(),
+                &mainline_map,
+                store,
+            );
+            order_map.insert(
+                ev_id,
+                (
+                    depth,
+                    event_map.get(ev_id).map(|ev| ev.origin_server_ts()),
+                    ev_id, // TODO should this be a &str to sort lexically??
+                ),
+            );
+
+            // We yield occasionally when we're working with large data sets to
+            // ensure that we don't block the reactor loop for too long.
+            if idx % _YIELD_AFTER_ITERATIONS == 0 {
+                // yield clock.sleep(0)
+            }
         }
 
-pub fn is_power_event(event: &&StateMap<EventId>) -> bool {
-    true
+        // sort the event_ids by their depth, timestamp and EventId
+        sort_event_ids.sort_by_key(|sort_id| order_map.get(sort_id).unwrap());
+
+        sort_event_ids
+    }
+
+    fn get_mainline_depth(
+        &mut self,
+        room_id: &RoomId,
+        mut event: Option<StateEvent>,
+        mainline_map: &EventMap<usize>,
+        store: &dyn StateStore,
+    ) -> usize {
+        while let Some(sort_ev) = event {
+            if let Some(id) = sort_ev.event_id() {
+                if let Some(depth) = mainline_map.get(id) {
+                    return *depth;
+                }
+            }
+
+            let auth_events = if let Some(id) = sort_ev.event_id() {
+                store.auth_event_ids(room_id, id).unwrap()
+            } else {
+                vec![]
+            };
+            event = None;
+
+            for aid in auth_events {
+                let aev = store.get_event(&aid).unwrap();
+                if aev.is_type_and_key(EventType::RoomPowerLevels, "") {
+                    event = Some(aev);
+                    break;
+                }
+            }
+        }
+        // Did not find a power level event so we default to zero
+        0
+    }
+}
+
+pub fn is_power_event(event_id: &EventId, store: &dyn StateStore) -> bool {
+    match store.get_event(event_id) {
+        Ok(state) => state.is_power_event(),
+        _ => false, // TODO this shouldn't eat errors
+    }
 }
 
 #[cfg(test)]

src/state_event.rs

@@ -1,8 +1,13 @@
-use ruma::events::{
-    from_raw_json_value, AnyStateEvent, AnyStrippedStateEvent, AnySyncStateEvent, EventDeHelper,
+use ruma::{
+    events::{
+        from_raw_json_value, room::member::MembershipState, AnyStateEvent, AnyStrippedStateEvent,
+        AnySyncStateEvent, EventDeHelper, EventType,
+    },
+    identifiers::{EventId, RoomId},
 };
 use serde::{de, Serialize};
 use serde_json::value::RawValue as RawJsonValue;
+use std::{convert::TryFrom, time::SystemTime};
 
 #[derive(Clone, Debug, Serialize)]
 #[serde(untagged)]
@@ -12,6 +17,74 @@ pub enum StateEvent {
     Stripped(AnyStrippedStateEvent),
 }
 
+impl StateEvent {
+    pub fn is_power_event(&self) -> bool {
+        match self {
+            Self::Full(any_event) => match any_event {
+                AnyStateEvent::RoomPowerLevels(event) => event.state_key == "",
+                AnyStateEvent::RoomJoinRules(event) => event.state_key == "",
+                AnyStateEvent::RoomCreate(event) => event.state_key == "",
+                AnyStateEvent::RoomMember(event) => {
+                    if [MembershipState::Leave, MembershipState::Ban]
+                        .contains(&event.content.membership)
+                    {
+                        return event.sender.as_str() != event.state_key;
+                    }
+                    false
+                }
+                _ => false,
+            },
+            Self::Sync(any_event) => match any_event {
+                AnySyncStateEvent::RoomPowerLevels(event) => event.state_key == "",
+                AnySyncStateEvent::RoomJoinRules(event) => event.state_key == "",
+                AnySyncStateEvent::RoomCreate(event) => event.state_key == "",
+                AnySyncStateEvent::RoomMember(event) => {
+                    if [MembershipState::Leave, MembershipState::Ban]
+                        .contains(&event.content.membership)
+                    {
+                        return event.sender.as_str() != event.state_key;
+                    }
+                    false
+                }
+                _ => false,
+            },
+            Self::Stripped(any_event) => match any_event {
+                AnyStrippedStateEvent::RoomPowerLevels(event) => event.state_key == "",
+                AnyStrippedStateEvent::RoomJoinRules(event) => event.state_key == "",
+                AnyStrippedStateEvent::RoomCreate(event) => event.state_key == "",
+                AnyStrippedStateEvent::RoomMember(event) => {
+                    if [MembershipState::Leave, MembershipState::Ban]
+                        .contains(&event.content.membership)
+                    {
+                        return event.sender.as_str() != event.state_key;
+                    }
+                    false
+                }
+                _ => false,
+            },
+            _ => false,
+        }
+    }
+    pub fn origin_server_ts(&self) -> Option<&SystemTime> {
+        match self {
+            Self::Full(ev) => Some(ev.origin_server_ts()),
+            Self::Sync(ev) => Some(ev.origin_server_ts()),
+            Self::Stripped(ev) => None,
+        }
+    }
+    pub fn event_id(&self) -> Option<&EventId> {
+        match self {
+            Self::Full(ev) => Some(ev.event_id()),
+            Self::Sync(ev) => Some(ev.event_id()),
+            Self::Stripped(ev) => None,
+        }
+    }
+
+    pub fn is_type_and_key(&self, ev_type: EventType, state_key: &str) -> bool {
+        true
+    }
+}
+
 impl<'de> de::Deserialize<'de> for StateEvent {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
     where

src/state_store.rs

@@ -12,8 +12,14 @@ use ruma::{
 use crate::StateEvent;
 
 pub trait StateStore {
+    /// Return a single event based on the EventId.
+    fn get_event(&self, event_id: &EventId) -> Result<StateEvent, String>;
+
     /// Returns the events that correspond to the `event_ids` sorted in the same order.
-    fn get_events(&self, event_ids: &[EventId]) -> Result<Vec<StateEvent>, serde_json::Error>;
+    fn get_events(&self, event_ids: &[EventId]) -> Result<Vec<StateEvent>, String>;
+
+    /// Returns a Vec of the related auth events to the given `event`.
+    fn auth_event_ids(&self, room_id: &RoomId, event_id: &EventId) -> Result<Vec<EventId>, String>;
 
     /// Returns a tuple of requested state events from `event_id` and the auth chain events that
     /// relate to the.
@@ -22,5 +28,5 @@ pub trait StateStore {
         room_id: &RoomId,
         version: &RoomVersionId,
         event_id: &EventId,
-    ) -> Result<(Vec<StateEvent>, Vec<StateEvent>), serde_json::Error>;
+    ) -> Result<(Vec<StateEvent>, Vec<StateEvent>), String>;
 }

tests/init.rs

@@ -1,5 +1,6 @@
-use std::convert::TryFrom;
+use std::{collections::BTreeMap, convert::TryFrom};
 
+use maplit::btreemap;
 use ruma::{
     events::{
         room::{self},
@@ -136,8 +137,22 @@ fn power_levels() -> JsonValue {
 pub struct TestStore;
 
 impl StateStore for TestStore {
-    fn get_events(&self, events: &[EventId]) -> Result<Vec<StateEvent>, serde_json::Error> {
-        Ok(vec![from_json_value(power_levels())?])
+    fn get_events(&self, events: &[EventId]) -> Result<Vec<StateEvent>, String> {
+        vec![room_create(), join_rules(), join_event(), power_levels()]
+            .into_iter()
+            .map(from_json_value)
+            .collect::<serde_json::Result<Vec<_>>>()
+            .map_err(|e| e.to_string())
+    }
+
+    fn get_event(&self, event_id: &EventId) -> Result<StateEvent, String> {
+        from_json_value(power_levels()).map_err(|e| e.to_string())
+    }
+
+    fn auth_event_ids(&self, room_id: &RoomId, event_id: &EventId) -> Result<Vec<EventId>, String> {
+        Ok(vec![
+            EventId::try_from("$aaa:example.org").map_err(|e| e.to_string())?
+        ])
     }
 
     fn get_remote_state_for_room(
@@ -145,10 +160,10 @@ impl StateStore for TestStore {
         room_id: &RoomId,
         version: &RoomVersionId,
         event_id: &EventId,
-    ) -> Result<(Vec<StateEvent>, Vec<StateEvent>), serde_json::Error> {
+    ) -> Result<(Vec<StateEvent>, Vec<StateEvent>), String> {
         Ok((
-            vec![from_json_value(federated_json())?],
-            vec![from_json_value(power_levels())?],
+            vec![from_json_value(federated_json()).map_err(|e| e.to_string())?],
+            vec![from_json_value(power_levels()).map_err(|e| e.to_string())?],
         ))
     }
 }
@@ -160,14 +175,18 @@ fn it_works() {
     let room_id = RoomId::try_from("!room_id:example.org").unwrap();
     let room_version = RoomVersionId::version_6();
 
-    let a = from_json_value::<StateEvent>(room_create()).unwrap();
-    let b = from_json_value::<StateEvent>(join_rules()).unwrap();
-    let c = from_json_value::<StateEvent>(join_event()).unwrap();
+    let initial_state = btreemap! {
+        (EventType::RoomCreate, "".into()) => EventId::try_from("").unwrap(),
+    };
+
+    let state_to_resolve = btreemap! {
+        (EventType::RoomCreate, "".into()) => EventId::try_from("").unwrap(),
+    };
 
     let mut resolver = StateResolution::default();
 
     let res = resolver
-        .resolve(&room_id, &room_version, vec![a.clone()], &mut store)
+        .resolve(&room_id, &room_version, vec![initial_state], &mut store)
         .unwrap();
     assert!(if let ResolutionResult::Resolved(_) = res {
         true
@@ -176,9 +195,10 @@ fn it_works() {
     });
 
     let resolved = resolver
-        .resolve(&room_id, &room_version, vec![b, c], &mut store)
+        .resolve(&room_id, &room_version, vec![state_to_resolve], &mut store)
         .unwrap();
 
     assert!(resolver.conflicting_events.is_empty());
     assert_eq!(resolver.resolved_events.len(), 3);
+    assert_eq!(resolver.resolved_events.len(), 3);
 }