draft of falling back to reading entries since last decrypted event key

this change notifyRoomKey(s) to only take one room key at a time
to simplify things
This commit is contained in:
Bruno Windels 2020-09-23 17:34:25 +02:00
parent a8392dc684
commit 9d41e122a0
5 changed files with 165 additions and 76 deletions

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@ -59,12 +59,12 @@ export class DeviceMessageHandler {
return {roomKeys};
}
_applyDecryptChanges(rooms, {roomKeys}) {
if (roomKeys && roomKeys.length) {
const roomKeysByRoom = groupBy(roomKeys, s => s.roomId);
for (const [roomId, roomKeys] of roomKeysByRoom) {
const room = rooms.get(roomId);
room?.notifyRoomKeys(roomKeys);
async _applyDecryptChanges(rooms, {roomKeys}) {
if (Array.isArray(roomKeys)) {
for (const roomKey of roomKeys) {
const room = rooms.get(roomKey.roomId);
// TODO: this is less parallized than it could be (like sync)
await room?.notifyRoomKey(roomKey);
}
}
}
@ -101,7 +101,7 @@ export class DeviceMessageHandler {
throw err;
}
await txn.complete();
this._applyDecryptChanges(rooms, changes);
await this._applyDecryptChanges(rooms, changes);
}
async _getPendingEvents(txn) {

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@ -42,8 +42,12 @@ export class RoomEncryption {
this._megolmBackfillCache = this._megolmDecryption.createSessionCache();
this._megolmSyncCache = this._megolmDecryption.createSessionCache();
// not `event_id`, but an internal event id passed in to the decrypt methods
this._eventIdsByMissingSession = new Map();
// session => event ids of messages we tried to decrypt and the session was missing
this._missingSessions = new SessionToEventIdsMap();
// sessions that may or may not be missing, but that while
// looking for a particular session came up as a candidate and were
// added to the cache to prevent further lookups from storage
this._missingSessionCandidates = new SessionToEventIdsMap();
this._senderDeviceCache = new Map();
this._storage = storage;
this._sessionBackup = sessionBackup;
@ -57,8 +61,7 @@ export class RoomEncryption {
return;
}
this._sessionBackup = sessionBackup;
for(const key of this._eventIdsByMissingSession.keys()) {
const {senderKey, sessionId} = decodeMissingSessionKey(key);
for(const {senderKey, sessionId} of this._missingSessions.getSessions()) {
await this._requestMissingSessionFromBackup(senderKey, sessionId, null);
}
}
@ -115,13 +118,17 @@ export class RoomEncryption {
if (customCache) {
customCache.dispose();
}
return new DecryptionPreparation(preparation, errors, {isTimelineOpen, source}, this);
return new DecryptionPreparation(preparation, errors, {isTimelineOpen, source}, this, events);
}
async _processDecryptionResults(results, errors, flags, txn) {
for (const error of errors.values()) {
if (error.code === "MEGOLM_NO_SESSION") {
this._addMissingSessionEvent(error.event, flags.source);
async _processDecryptionResults(events, results, errors, flags, txn) {
for (const event of events) {
const error = errors.get(event.event_id);
if (error?.code === "MEGOLM_NO_SESSION") {
this._addMissingSessionEvent(event, flags.source);
} else {
this._missingSessions.removeEvent(event);
this._missingSessionCandidates.removeEvent(event);
}
}
if (flags.isTimelineOpen) {
@ -145,17 +152,12 @@ export class RoomEncryption {
}
_addMissingSessionEvent(event, source) {
const senderKey = event.content?.["sender_key"];
const sessionId = event.content?.["session_id"];
const key = encodeMissingSessionKey(senderKey, sessionId);
let eventIds = this._eventIdsByMissingSession.get(key);
// new missing session
if (!eventIds) {
const isNewSession = this._missingSessions.addEvent(event);
if (isNewSession) {
const senderKey = event.content?.["sender_key"];
const sessionId = event.content?.["session_id"];
this._requestMissingSessionFromBackup(senderKey, sessionId, source);
eventIds = new Set();
this._eventIdsByMissingSession.set(key, eventIds);
}
eventIds.add(event.event_id);
}
async _requestMissingSessionFromBackup(senderKey, sessionId, source) {
@ -163,7 +165,7 @@ export class RoomEncryption {
// and only after that proceed to request from backup
if (source === DecryptionSource.Sync) {
await this._clock.createTimeout(10000).elapsed();
if (this._disposed || !this._eventIdsByMissingSession.has(encodeMissingSessionKey(senderKey, sessionId))) {
if (this._disposed || !this._missingSessions.hasSession(senderKey, sessionId)) {
return;
}
}
@ -192,8 +194,8 @@ export class RoomEncryption {
await txn.complete();
if (roomKey) {
// this will call into applyRoomKeys below
await this._room.notifyRoomKeys([roomKey]);
// this will reattempt decryption
await this._room.notifyRoomKey(roomKey);
}
} else if (session?.algorithm) {
console.info(`Backed-up session of unknown algorithm: ${session.algorithm}`);
@ -212,18 +214,17 @@ export class RoomEncryption {
* @param {Array<RoomKeyDescription>} roomKeys
* @return {Array<string>} the event ids that should be retried to decrypt
*/
applyRoomKeys(roomKeys) {
// retry decryption with the new sessions
const retryEventIds = [];
for (const roomKey of roomKeys) {
const key = encodeMissingSessionKey(roomKey.senderKey, roomKey.sessionId);
const entriesForSession = this._eventIdsByMissingSession.get(key);
if (entriesForSession) {
this._eventIdsByMissingSession.delete(key);
retryEventIds.push(...entriesForSession);
}
getEventIdsForRoomKey(roomKey) {
let eventIds = this._missingSessions.getEventIds(roomKey.senderKey, roomKey.sessionId);
if (!eventIds) {
eventIds = this._missingSessionCandidates.getEventIds(roomKey.senderKey, roomKey.sessionId);
}
return retryEventIds;
return eventIds;
}
findAndCacheEntriesForRoomKey(roomKey, candidateEntries) {
// add all to _missingSessionCandidates
// filter messages to roomKey
}
async encrypt(type, content, hsApi) {
@ -354,11 +355,12 @@ export class RoomEncryption {
* the decryption results before turning them
*/
class DecryptionPreparation {
constructor(megolmDecryptionPreparation, extraErrors, flags, roomEncryption) {
constructor(megolmDecryptionPreparation, extraErrors, flags, roomEncryption, events) {
this._megolmDecryptionPreparation = megolmDecryptionPreparation;
this._extraErrors = extraErrors;
this._flags = flags;
this._roomEncryption = roomEncryption;
this._events = events;
}
async decrypt() {
@ -366,7 +368,8 @@ class DecryptionPreparation {
await this._megolmDecryptionPreparation.decrypt(),
this._extraErrors,
this._flags,
this._roomEncryption);
this._roomEncryption,
this._events);
}
dispose() {
@ -375,17 +378,18 @@ class DecryptionPreparation {
}
class DecryptionChanges {
constructor(megolmDecryptionChanges, extraErrors, flags, roomEncryption) {
constructor(megolmDecryptionChanges, extraErrors, flags, roomEncryption, events) {
this._megolmDecryptionChanges = megolmDecryptionChanges;
this._extraErrors = extraErrors;
this._flags = flags;
this._roomEncryption = roomEncryption;
this._events = events;
}
async write(txn) {
const {results, errors} = await this._megolmDecryptionChanges.write(txn);
mergeMap(this._extraErrors, errors);
await this._roomEncryption._processDecryptionResults(results, errors, this._flags, txn);
await this._roomEncryption._processDecryptionResults(this._events, results, errors, this._flags, txn);
return new BatchDecryptionResult(results, errors);
}
}
@ -410,3 +414,58 @@ class BatchDecryptionResult {
}
}
}
class SessionToEventIdsMap {
constructor() {
this._eventIdsBySession = new Map();
}
addEvent(event) {
let isNewSession = false;
const senderKey = event.content?.["sender_key"];
const sessionId = event.content?.["session_id"];
const key = encodeMissingSessionKey(senderKey, sessionId);
let eventIds = this._eventIdsBySession.get(key);
// new missing session
if (!eventIds) {
eventIds = new Set();
this._eventIdsBySession.set(key, eventIds);
isNewSession = true;
}
eventIds.add(event.event_id);
return isNewSession;
}
getEventIds(senderKey, sessionId) {
const key = encodeMissingSessionKey(senderKey, sessionId);
const entriesForSession = this._eventIdsBySession.get(key);
if (entriesForSession) {
return [...entriesForSession];
}
}
getSessions() {
return Array.from(this._eventIdsBySession.keys()).map(decodeMissingSessionKey);
}
hasSession(senderKey, sessionId) {
return this._eventIdsBySession.has(encodeMissingSessionKey(senderKey, sessionId));
}
removeEvent(event) {
let hasRemovedSession = false;
const senderKey = event.content?.["sender_key"];
const sessionId = event.content?.["session_id"];
const key = encodeMissingSessionKey(senderKey, sessionId);
let eventIds = this._eventIdsBySession.get(key);
if (eventIds) {
if (eventIds.delete(event.event_id)) {
if (!eventIds.length) {
this._eventIdsBySession.delete(key);
hasRemovedSession = true;
}
}
}
return hasRemovedSession;
}
}

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@ -52,42 +52,63 @@ export class Room extends EventEmitter {
this._clock = clock;
}
_readEntriesToRetryDecryption(retryEventIds) {
const readFromEventKey = retryEventIds.length !== 0;
const stores =
const txn = await this._storage.readTxn([
this._storage.storeNames.timelineEvents,
this._storage.storeNames.inboundGroupSessions,
]);
_readRetryDecryptCandidateEntries(sinceEventKey, txn) {
if (sinceEventKey) {
return readFromWithTxn(sinceEventKey, Direction.Forward, Number.MAX_SAFE_INTEGER, txn);
} else {
// all messages for room
return readFromWithTxn(this._syncWriter.lastMessageKey, Direction.Backward, Number.MAX_SAFE_INTEGER, txn);
}
}
async notifyRoomKeys(roomKeys) {
if (this._roomEncryption) {
let retryEventIds = this._roomEncryption.applyRoomKeys(roomKeys);
if (retryEventIds.length) {
const retryEntries = [];
const txn = await this._storage.readTxn([
this._storage.storeNames.timelineEvents,
this._storage.storeNames.inboundGroupSessions,
]);
for (const eventId of retryEventIds) {
const storageEntry = await txn.timelineEvents.getByEventId(this._roomId, eventId);
if (storageEntry) {
retryEntries.push(new EventEntry(storageEntry, this._fragmentIdComparer));
}
async notifyRoomKey(roomKey) {
if (!this._roomEncryption) {
return;
}
const retryEventIds = this._roomEncryption.getEventIdsForRoomKey(roomKey);
const stores = [
this._storage.storeNames.timelineEvents,
this._storage.storeNames.inboundGroupSessions,
];
let txn;
let retryEntries;
if (retryEventIds) {
retryEntries = [];
txn = await this._storage.readTxn(stores);
for (const eventId of retryEventIds) {
const storageEntry = await txn.timelineEvents.getByEventId(this._roomId, eventId);
if (storageEntry) {
retryEntries.push(new EventEntry(storageEntry, this._fragmentIdComparer));
}
const decryptRequest = this._decryptEntries(DecryptionSource.Retry, retryEntries, txn);
await decryptRequest.complete();
}
} else {
// we only look for messages since lastDecryptedEventKey because
// the timeline must be closed (otherwise getEventIdsForRoomKey would have found the event ids)
// and to update the summary we only care about events since lastDecryptedEventKey
const key = this._summary.data.lastDecryptedEventKey;
// key might be missing if we haven't decrypted any events in this room
const sinceEventKey = key && new EventKey(key.fragmentId, key.entryIndex);
// check we have not already decrypted the most recent event in the room
// otherwise we know that the messages for this room key will not update the room summary
if (!sinceEventKey || !sinceEventKey.equals(this._syncWriter.lastMessageKey)) {
txn = await this._storage.readTxn(stores.concat(this._storage.storeNames.timelineFragments));
const candidateEntries = await this._readRetryDecryptCandidateEntries(sinceEventKey, txn);
retryEntries = this._roomEncryption.findAndCacheEntriesForRoomKey(roomKey, candidateEntries);
}
}
if (retryEntries?.length) {
const decryptRequest = this._decryptEntries(DecryptionSource.Retry, retryEntries, txn);
// this will close txn while awaiting decryption
await decryptRequest.complete();
this._timeline?.replaceEntries(retryEntries);
// we would ideally write the room summary in the same txn as the groupSessionDecryptions in the
// _decryptEntries entries and could even know which events have been decrypted for the first
// time from DecryptionChanges.write and only pass those to the summary. As timeline changes
// are not essential to the room summary, it's fine to write this in a separate txn for now.
const changes = this._summary.data.applyTimelineEntries(retryEntries, false, this._isTimelineOpen);
if (await this._summary.writeAndApplyData(changes, this._storage)) {
this._emitUpdate();
}
this._timeline?.replaceEntries(retryEntries);
// we would ideally write the room summary in the same txn as the groupSessionDecryptions in the
// _decryptEntries entries and could even know which events have been decrypted for the first
// time from DecryptionChanges.write and only pass those to the summary. As timeline changes
// are not essential to the room summary, it's fine to write this in a separate txn for now.
const changes = this._summary.data.applyTimelineEntries(retryEntries, false, this._isTimelineOpen);
if (await this._summary.writeAndApplyData(changes, this._storage)) {
this._emitUpdate();
}
}
}
@ -203,7 +224,7 @@ export class Room extends EventEmitter {
heroChanges = await this._heroes.calculateChanges(summaryChanges.heroes, memberChanges, txn);
}
let removedPendingEvents;
if (roomResponse.timeline && roomResponse.timeline.events) {
if (Array.isArray(roomResponse.timeline?.events)) {
removedPendingEvents = this._sendQueue.removeRemoteEchos(roomResponse.timeline.events, txn);
}
return {

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@ -63,6 +63,10 @@ export class EventKey {
toString() {
return `[${this.fragmentId}/${this.eventIndex}]`;
}
equals(other) {
return this.fragmentId === other?.fragmentId && this.eventIndex === other?.eventIndex;
}
}
export function xtests() {

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@ -46,6 +46,7 @@ export async function readFromWithTxn(eventKey, direction, amount, r, txn) {
while (entries.length < amount && eventKey) {
let eventsWithinFragment;
if (direction.isForward) {
// TODO: should we pass amount - entries.length here?
eventsWithinFragment = await timelineStore.eventsAfter(this._roomId, eventKey, amount);
} else {
eventsWithinFragment = await timelineStore.eventsBefore(this._roomId, eventKey, amount);
@ -56,6 +57,10 @@ export async function readFromWithTxn(eventKey, direction, amount, r, txn) {
if (entries.length < amount) {
const fragment = await fragmentStore.get(this._roomId, eventKey.fragmentId);
// TODO: why does the first fragment not need to be added? (the next *is* added below)
// it looks like this would be fine when loading in the sync island
// (as the live fragment should be added already) but not for permalinks when we support them
//
// this._fragmentIdComparer.addFragment(fragment);
let fragmentEntry = new FragmentBoundaryEntry(fragment, direction.isBackward, this._fragmentIdComparer);
// append or prepend fragmentEntry, reuse func from GapWriter?