hydrogen-web/src/matrix/storage/idb/stores/TimelineEventStore.js

250 lines
10 KiB
JavaScript

import EventKey from "../../../room/timeline/EventKey.js";
import { StorageError } from "../../common.js";
import { encodeUint32 } from "../utils.js";
import Platform from "../../../../Platform.js";
function encodeKey(roomId, fragmentId, eventIndex) {
return `${roomId}|${encodeUint32(fragmentId)}|${encodeUint32(eventIndex)}`;
}
function encodeEventIdKey(roomId, eventId) {
return `${roomId}|${eventId}`;
}
function decodeEventIdKey(eventIdKey) {
const [roomId, eventId] = eventIdKey.split("|");
return {roomId, eventId};
}
class Range {
constructor(only, lower, upper, lowerOpen, upperOpen) {
this._only = only;
this._lower = lower;
this._upper = upper;
this._lowerOpen = lowerOpen;
this._upperOpen = upperOpen;
}
asIDBKeyRange(roomId) {
try {
// only
if (this._only) {
return IDBKeyRange.only(encodeKey(roomId, this._only.fragmentId, this._only.eventIndex));
}
// lowerBound
// also bound as we don't want to move into another roomId
if (this._lower && !this._upper) {
return IDBKeyRange.bound(
encodeKey(roomId, this._lower.fragmentId, this._lower.eventIndex),
encodeKey(roomId, this._lower.fragmentId, Platform.maxStorageKey),
this._lowerOpen,
false
);
}
// upperBound
// also bound as we don't want to move into another roomId
if (!this._lower && this._upper) {
return IDBKeyRange.bound(
encodeKey(roomId, this._upper.fragmentId, Platform.minStorageKey),
encodeKey(roomId, this._upper.fragmentId, this._upper.eventIndex),
false,
this._upperOpen
);
}
// bound
if (this._lower && this._upper) {
return IDBKeyRange.bound(
encodeKey(roomId, this._lower.fragmentId, this._lower.eventIndex),
encodeKey(roomId, this._upper.fragmentId, this._upper.eventIndex),
this._lowerOpen,
this._upperOpen
);
}
} catch(err) {
throw new StorageError(`IDBKeyRange failed with data: ` + JSON.stringify(this), err);
}
}
}
/*
* @typedef {Object} Gap
* @property {?string} prev_batch the pagination token for this backwards facing gap
* @property {?string} next_batch the pagination token for this forwards facing gap
*
* @typedef {Object} Event
* @property {string} event_id the id of the event
* @property {string} type the
* @property {?string} state_key the state key of this state event
*
* @typedef {Object} Entry
* @property {string} roomId
* @property {EventKey} eventKey
* @property {?Event} event if an event entry, the event
* @property {?Gap} gap if a gap entry, the gap
*/
export default class TimelineEventStore {
constructor(timelineStore) {
this._timelineStore = timelineStore;
}
/** Creates a range that only includes the given key
* @param {EventKey} eventKey the key
* @return {Range} the created range
*/
onlyRange(eventKey) {
return new Range(eventKey);
}
/** Creates a range that includes all keys before eventKey, and optionally also the key itself.
* @param {EventKey} eventKey the key
* @param {boolean} [open=false] whether the key is included (false) or excluded (true) from the range at the upper end.
* @return {Range} the created range
*/
upperBoundRange(eventKey, open=false) {
return new Range(undefined, undefined, eventKey, undefined, open);
}
/** Creates a range that includes all keys after eventKey, and optionally also the key itself.
* @param {EventKey} eventKey the key
* @param {boolean} [open=false] whether the key is included (false) or excluded (true) from the range at the lower end.
* @return {Range} the created range
*/
lowerBoundRange(eventKey, open=false) {
return new Range(undefined, eventKey, undefined, open);
}
/** Creates a range that includes all keys between `lower` and `upper`, and optionally the given keys as well.
* @param {EventKey} lower the lower key
* @param {EventKey} upper the upper key
* @param {boolean} [lowerOpen=false] whether the lower key is included (false) or excluded (true) from the range.
* @param {boolean} [upperOpen=false] whether the upper key is included (false) or excluded (true) from the range.
* @return {Range} the created range
*/
boundRange(lower, upper, lowerOpen=false, upperOpen=false) {
return new Range(undefined, lower, upper, lowerOpen, upperOpen);
}
/** Looks up the last `amount` entries in the timeline for `roomId`.
* @param {string} roomId
* @param {number} fragmentId
* @param {number} amount
* @return {Promise<Entry[]>} a promise resolving to an array with 0 or more entries, in ascending order.
*/
async lastEvents(roomId, fragmentId, amount) {
const eventKey = EventKey.maxKey;
eventKey.fragmentId = fragmentId;
return this.eventsBefore(roomId, eventKey, amount);
}
/** Looks up the first `amount` entries in the timeline for `roomId`.
* @param {string} roomId
* @param {number} fragmentId
* @param {number} amount
* @return {Promise<Entry[]>} a promise resolving to an array with 0 or more entries, in ascending order.
*/
async firstEvents(roomId, fragmentId, amount) {
const eventKey = EventKey.minKey;
eventKey.fragmentId = fragmentId;
return this.eventsAfter(roomId, eventKey, amount);
}
/** Looks up `amount` entries after `eventKey` in the timeline for `roomId` within the same fragment.
* The entry for `eventKey` is not included.
* @param {string} roomId
* @param {EventKey} eventKey
* @param {number} amount
* @return {Promise<Entry[]>} a promise resolving to an array with 0 or more entries, in ascending order.
*/
eventsAfter(roomId, eventKey, amount) {
const idbRange = this.lowerBoundRange(eventKey, true).asIDBKeyRange(roomId);
return this._timelineStore.selectLimit(idbRange, amount);
}
/** Looks up `amount` entries before `eventKey` in the timeline for `roomId` within the same fragment.
* The entry for `eventKey` is not included.
* @param {string} roomId
* @param {EventKey} eventKey
* @param {number} amount
* @return {Promise<Entry[]>} a promise resolving to an array with 0 or more entries, in ascending order.
*/
async eventsBefore(roomId, eventKey, amount) {
const range = this.upperBoundRange(eventKey, true).asIDBKeyRange(roomId);
const events = await this._timelineStore.selectLimitReverse(range, amount);
events.reverse(); // because we fetched them backwards
return events;
}
/** Finds the first eventId that occurs in the store, if any.
* For optimal performance, `eventIds` should be in chronological order.
*
* The order in which results are returned might be different than `eventIds`.
* Call the return value to obtain the next {id, event} pair.
* @param {string} roomId
* @param {string[]} eventIds
* @return {Function<Promise>}
*/
// performance comment from above refers to the fact that there *might*
// be a correlation between event_id sorting order and chronology.
// In that case we could avoid running over all eventIds, as the reported order by findExistingKeys
// would match the order of eventIds. That's why findLast is also passed as backwards to keysExist.
// also passing them in chronological order makes sense as that's how we'll receive them almost always.
async findFirstOccurringEventId(roomId, eventIds) {
const byEventId = this._timelineStore.index("byEventId");
const keys = eventIds.map(eventId => encodeEventIdKey(roomId, eventId));
const results = new Array(keys.length);
let firstFoundKey;
// find first result that is found and has no undefined results before it
function firstFoundAndPrecedingResolved() {
for(let i = 0; i < results.length; ++i) {
if (results[i] === undefined) {
return;
} else if(results[i] === true) {
return keys[i];
}
}
}
await byEventId.findExistingKeys(keys, false, (key, found) => {
const index = keys.indexOf(key);
results[index] = found;
firstFoundKey = firstFoundAndPrecedingResolved();
return !!firstFoundKey;
});
return firstFoundKey && decodeEventIdKey(firstFoundKey).eventId;
}
/** Inserts a new entry into the store. The combination of roomId and eventKey should not exist yet, or an error is thrown.
* @param {Entry} entry the entry to insert
* @return {Promise<>} a promise resolving to undefined if the operation was successful, or a StorageError if not.
* @throws {StorageError} ...
*/
insert(entry) {
entry.key = encodeKey(entry.roomId, entry.fragmentId, entry.eventIndex);
entry.eventIdKey = encodeEventIdKey(entry.roomId, entry.event.event_id);
// TODO: map error? or in idb/store?
return this._timelineStore.add(entry);
}
/** Updates the entry into the store with the given [roomId, eventKey] combination.
* If not yet present, will insert. Might be slower than add.
* @param {Entry} entry the entry to update.
* @return {Promise<>} a promise resolving to undefined if the operation was successful, or a StorageError if not.
*/
update(entry) {
return this._timelineStore.put(entry);
}
get(roomId, eventKey) {
return this._timelineStore.get(encodeKey(roomId, eventKey.fragmentId, eventKey.eventIndex));
}
// returns the entries as well!! (or not always needed? I guess not always needed, so extra method)
removeRange(roomId, range) {
// TODO: read the entries!
return this._timelineStore.delete(range.asIDBKeyRange(roomId));
}
getByEventId(roomId, eventId) {
return this._timelineStore.index("byEventId").get(encodeEventIdKey(roomId, eventId));
}
}