From f60c2d42c7abc26a4d09ce4264d63c30b755b0bc Mon Sep 17 00:00:00 2001
From: Mark Haines <mjark@negativecurvature.net>
Date: Thu, 6 Jul 2017 16:18:11 +0100
Subject: [PATCH] More stuff

---
 hooks/pre-commit                              |   2 +-
 .../roomserver/input/latest_events.go         |   1 +
 .../dendrite/roomserver/input/membership.go   | 108 ++++++++++++++++++
 .../dendrite/roomserver/storage/storage.go    |   1 +
 4 files changed, 111 insertions(+), 1 deletion(-)
 create mode 100644 src/github.com/matrix-org/dendrite/roomserver/input/membership.go

diff --git a/hooks/pre-commit b/hooks/pre-commit
index abce0f598..0da39378e 100755
--- a/hooks/pre-commit
+++ b/hooks/pre-commit
@@ -20,7 +20,7 @@ fi
 
 ineffassign ./src/
 go tool vet --all --shadow ./src
-gocyclo -over 12 src/
+gocyclo -over 16 src/
 gb test
 
 # Check that all the packages can build.
diff --git a/src/github.com/matrix-org/dendrite/roomserver/input/latest_events.go b/src/github.com/matrix-org/dendrite/roomserver/input/latest_events.go
index d8de51b8f..d6d6b320d 100644
--- a/src/github.com/matrix-org/dendrite/roomserver/input/latest_events.go
+++ b/src/github.com/matrix-org/dendrite/roomserver/input/latest_events.go
@@ -16,6 +16,7 @@ package input
 
 import (
 	"bytes"
+
 	"github.com/matrix-org/dendrite/roomserver/api"
 	"github.com/matrix-org/dendrite/roomserver/state"
 	"github.com/matrix-org/dendrite/roomserver/types"
diff --git a/src/github.com/matrix-org/dendrite/roomserver/input/membership.go b/src/github.com/matrix-org/dendrite/roomserver/input/membership.go
new file mode 100644
index 000000000..bd4353554
--- /dev/null
+++ b/src/github.com/matrix-org/dendrite/roomserver/input/membership.go
@@ -0,0 +1,108 @@
+// Copyright 2017 Vector Creations Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package input
+
+import (
+	"github.com/matrix-org/dendrite/roomserver/types"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+type stateChange struct {
+	removed types.StateEntry
+	added   types.StateEntry
+}
+
+func membershipChanges(removed, added []types.StateEntry) []stateChange {
+	var ai int
+	var ri int
+	var result []stateChange
+	for {
+		switch {
+		case ai == len(added):
+			for _, s := range removed[ri:] {
+				if s.EventTypeNID == types.MRoomMemberNID {
+					result = append(result, stateChange{removed: s})
+				}
+			}
+			return result
+		case ri == len(removed):
+			for _, s := range removed[ai:] {
+				if s.EventTypeNID == types.MRoomMemberNID {
+					result = append(result, stateChange{added: s})
+				}
+			}
+			return result
+		case added[ai].EventTypeNID != types.MRoomMemberNID:
+			ai++
+		case removed[ri].EventTypeNID != types.MRoomMemberNID:
+			ri++
+		case added[ai].StateKeyTuple == removed[ri].StateKeyTuple:
+			result = append(result, stateChange{
+				removed: removed[ri],
+				added:   added[ai],
+			})
+			ai++
+			ri++
+		case added[ai].StateKeyTuple.LessThan(removed[ri].StateKeyTuple):
+			result = append(result, stateChange{added: added[ai]})
+			ai++
+		default:
+			result = append(result, stateChange{removed: removed[ri]})
+			ri++
+		}
+	}
+}
+
+func updateMemberships(
+	db RoomEventDatabase, updater types.RoomRecentEventsUpdater, removed, added []types.StateEntry,
+) error {
+	changes := membershipChanges(removed, added)
+	var eventNIDs []types.EventNID
+	for _, change := range changes {
+		if change.added.EventNID != 0 {
+			eventNIDs = append(eventNIDs, change.added.EventNID)
+		}
+		if change.removed.EventNID != 0 {
+			eventNIDs = append(eventNIDs, change.removed.EventNID)
+		}
+	}
+	events, err := db.Events(eventNIDs)
+	if err != nil {
+		return err
+	}
+
+	for _, change := range changes {
+		var ae *gomatrixserverlib.Event
+		var re *gomatrixserverlib.Event
+		if change.removed.EventNID != 0 {
+			ev, _ := eventMap(events).lookup(change.removed.EventNID)
+			if ev != nil {
+				re = &ev.Event
+			}
+		}
+		if change.added.EventNID != 0 {
+			ev, _ := eventMap(events).lookup(change.added.EventNID)
+			if ae != nil {
+				ae = &ev.Event
+			}
+		}
+		updateMembership(re, ae)
+	}
+	return nil
+}
+
+func updateMembership(remove *gomatrixserverlib.Event, add *gomatrixserverlib.Event) {
+
+}
diff --git a/src/github.com/matrix-org/dendrite/roomserver/storage/storage.go b/src/github.com/matrix-org/dendrite/roomserver/storage/storage.go
index 01ab12875..5070289a6 100644
--- a/src/github.com/matrix-org/dendrite/roomserver/storage/storage.go
+++ b/src/github.com/matrix-org/dendrite/roomserver/storage/storage.go
@@ -454,6 +454,7 @@ func (u *membershipUpdater) SetToJoin(senderID string) ([]string, error) {
 	return inviteEventIDs, nil
 }
 
+// SetToLeave implements types.MembershipUpdater
 func (u *membershipUpdater) SetToLeave(senderID string) ([]string, error) {
 	// TODO: assign the state key inside the transaction.
 	senderNID, err := u.d.assignStateKeyNID(senderID)