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Kegan Dougal 2017-04-18 17:33:53 +01:00
parent f18d935134
commit 95f7fef997
1 changed files with 33 additions and 1 deletions
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34
src/github.com/matrix-org/dendrite/syncserver/sync/requestpool.go
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@ -139,7 +139,8 @@ func (rp *RequestPool) currentSyncForUser(req syncRequest) (*types.Response, err
// TODO: handle ignored users
// TODO: Implement https://github.com/matrix-org/synapse/blob/v0.19.3/synapse/handlers/sync.py#L821
// TODO: Work out *which* rooms to return to the client
// Based on https://github.com/matrix-org/synapse/blob/v0.19.3/synapse/handlers/sync.py#L821
// 1) Get the CURRENT joined room list for this user
// 2) Get membership list changes for this user between the provided stream position and now.
// 3) For each room which has membership list changes:
@ -149,6 +150,37 @@ func (rp *RequestPool) currentSyncForUser(req syncRequest) (*types.Response, err
// c) Check if the user is CURRENTLY left/banned. If so, add room to 'archived' block. // Synapse has a TODO: How do we handle ban -> leave in same batch?
// 4) Add joined rooms (joined room list)
// Problem statement:
// TODO: For each room being returned, work out *which* events to return to the client.
// This involves calculating the room state at various points in the history of the room.
// For example, imagine a room with the following 15 events (letters are state events (updated via '), numbers are timeline events):
//
// index 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 (1-based indexing as StreamPosition(0) represents no event)
// timeline [A, B, C, D, 1, 2, 3, D', 4, D'', 5, B', D''', D'''', 6]
//
// The current state of this room is: [A, B', C, D'''']
//
//
// If this room was requested with ?since=9&limit=5 then 5 timeline events would be returned, the most recent ones:
// 11 12 13 14 15
// [5, B', D''', D'''', 6]
//
// The state of the room at the START of the timeline can be represented in 2 ways:
// - The 'full_state' from index 0 : [A, B, C, D''] (aka the state between 0-11 exclusive)
// - A partial state from index 9 : [D''] (aka the state between 9-11 exclusive)
//
// The /sync response returns the most recent timeline events and the state of the room at the start of the timeline, for each room.
//
// Aside: There are 2 ways that a server can advance state events e.g from D' to D'':
// 1) by a tuple of (event type, state key)
// 2) by the state conflict resolution algorithm
// Dendrite MUST do this by 2), and that is represented by the add_state_ids and remove_state_ids that
// are in OutputRoomEvents from the room server.
// This version of dendrite uses very simple indexing to calculate room state at various points.
// This is inefficient when a very old 'since' value is provided, or the 'full_state' is requested, as the state delta becomes
// very large. This is mitigated slightly with indexes, but better data structures could be used.
evs, err := rp.db.EventsInRange(req.since, currentPos)
if err != nil {
return nil, err