266 lines
11 KiB
JavaScript
266 lines
11 KiB
JavaScript
/*
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Copyright 2020 Bruno Windels <bruno@windels.cloud>
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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import {EventKey} from "../../../room/timeline/EventKey.js";
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import { StorageError } from "../../common.js";
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import { encodeUint32 } from "../utils.js";
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import {Platform} from "../../../../Platform.js";
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function encodeKey(roomId, fragmentId, eventIndex) {
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return `${roomId}|${encodeUint32(fragmentId)}|${encodeUint32(eventIndex)}`;
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}
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function encodeEventIdKey(roomId, eventId) {
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return `${roomId}|${eventId}`;
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}
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function decodeEventIdKey(eventIdKey) {
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const [roomId, eventId] = eventIdKey.split("|");
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return {roomId, eventId};
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}
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class Range {
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constructor(only, lower, upper, lowerOpen, upperOpen) {
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this._only = only;
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this._lower = lower;
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this._upper = upper;
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this._lowerOpen = lowerOpen;
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this._upperOpen = upperOpen;
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}
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asIDBKeyRange(roomId) {
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try {
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// only
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if (this._only) {
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return IDBKeyRange.only(encodeKey(roomId, this._only.fragmentId, this._only.eventIndex));
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}
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// lowerBound
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// also bound as we don't want to move into another roomId
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if (this._lower && !this._upper) {
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return IDBKeyRange.bound(
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encodeKey(roomId, this._lower.fragmentId, this._lower.eventIndex),
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encodeKey(roomId, this._lower.fragmentId, Platform.maxStorageKey),
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this._lowerOpen,
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false
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);
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}
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// upperBound
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// also bound as we don't want to move into another roomId
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if (!this._lower && this._upper) {
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return IDBKeyRange.bound(
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encodeKey(roomId, this._upper.fragmentId, Platform.minStorageKey),
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encodeKey(roomId, this._upper.fragmentId, this._upper.eventIndex),
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false,
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this._upperOpen
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);
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}
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// bound
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if (this._lower && this._upper) {
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return IDBKeyRange.bound(
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encodeKey(roomId, this._lower.fragmentId, this._lower.eventIndex),
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encodeKey(roomId, this._upper.fragmentId, this._upper.eventIndex),
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this._lowerOpen,
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this._upperOpen
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);
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}
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} catch(err) {
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throw new StorageError(`IDBKeyRange failed with data: ` + JSON.stringify(this), err);
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}
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}
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}
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/*
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* @typedef {Object} Gap
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* @property {?string} prev_batch the pagination token for this backwards facing gap
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* @property {?string} next_batch the pagination token for this forwards facing gap
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*
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* @typedef {Object} Event
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* @property {string} event_id the id of the event
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* @property {string} type the
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* @property {?string} state_key the state key of this state event
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*
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* @typedef {Object} Entry
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* @property {string} roomId
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* @property {EventKey} eventKey
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* @property {?Event} event if an event entry, the event
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* @property {?Gap} gap if a gap entry, the gap
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*/
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export class TimelineEventStore {
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constructor(timelineStore) {
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this._timelineStore = timelineStore;
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}
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/** Creates a range that only includes the given key
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* @param {EventKey} eventKey the key
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* @return {Range} the created range
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*/
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onlyRange(eventKey) {
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return new Range(eventKey);
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}
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/** Creates a range that includes all keys before eventKey, and optionally also the key itself.
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* @param {EventKey} eventKey the key
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* @param {boolean} [open=false] whether the key is included (false) or excluded (true) from the range at the upper end.
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* @return {Range} the created range
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*/
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upperBoundRange(eventKey, open=false) {
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return new Range(undefined, undefined, eventKey, undefined, open);
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}
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/** Creates a range that includes all keys after eventKey, and optionally also the key itself.
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* @param {EventKey} eventKey the key
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* @param {boolean} [open=false] whether the key is included (false) or excluded (true) from the range at the lower end.
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* @return {Range} the created range
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*/
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lowerBoundRange(eventKey, open=false) {
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return new Range(undefined, eventKey, undefined, open);
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}
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/** Creates a range that includes all keys between `lower` and `upper`, and optionally the given keys as well.
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* @param {EventKey} lower the lower key
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* @param {EventKey} upper the upper key
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* @param {boolean} [lowerOpen=false] whether the lower key is included (false) or excluded (true) from the range.
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* @param {boolean} [upperOpen=false] whether the upper key is included (false) or excluded (true) from the range.
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* @return {Range} the created range
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*/
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boundRange(lower, upper, lowerOpen=false, upperOpen=false) {
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return new Range(undefined, lower, upper, lowerOpen, upperOpen);
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}
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/** Looks up the last `amount` entries in the timeline for `roomId`.
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* @param {string} roomId
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* @param {number} fragmentId
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* @param {number} amount
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* @return {Promise<Entry[]>} a promise resolving to an array with 0 or more entries, in ascending order.
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*/
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async lastEvents(roomId, fragmentId, amount) {
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const eventKey = EventKey.maxKey;
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eventKey.fragmentId = fragmentId;
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return this.eventsBefore(roomId, eventKey, amount);
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}
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/** Looks up the first `amount` entries in the timeline for `roomId`.
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* @param {string} roomId
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* @param {number} fragmentId
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* @param {number} amount
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* @return {Promise<Entry[]>} a promise resolving to an array with 0 or more entries, in ascending order.
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*/
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async firstEvents(roomId, fragmentId, amount) {
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const eventKey = EventKey.minKey;
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eventKey.fragmentId = fragmentId;
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return this.eventsAfter(roomId, eventKey, amount);
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}
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/** Looks up `amount` entries after `eventKey` in the timeline for `roomId` within the same fragment.
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* The entry for `eventKey` is not included.
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* @param {string} roomId
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* @param {EventKey} eventKey
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* @param {number} amount
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* @return {Promise<Entry[]>} a promise resolving to an array with 0 or more entries, in ascending order.
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*/
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eventsAfter(roomId, eventKey, amount) {
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const idbRange = this.lowerBoundRange(eventKey, true).asIDBKeyRange(roomId);
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return this._timelineStore.selectLimit(idbRange, amount);
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}
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/** Looks up `amount` entries before `eventKey` in the timeline for `roomId` within the same fragment.
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* The entry for `eventKey` is not included.
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* @param {string} roomId
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* @param {EventKey} eventKey
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* @param {number} amount
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* @return {Promise<Entry[]>} a promise resolving to an array with 0 or more entries, in ascending order.
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*/
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async eventsBefore(roomId, eventKey, amount) {
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const range = this.upperBoundRange(eventKey, true).asIDBKeyRange(roomId);
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const events = await this._timelineStore.selectLimitReverse(range, amount);
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events.reverse(); // because we fetched them backwards
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return events;
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}
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/** Finds the first eventId that occurs in the store, if any.
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* For optimal performance, `eventIds` should be in chronological order.
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*
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* The order in which results are returned might be different than `eventIds`.
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* Call the return value to obtain the next {id, event} pair.
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* @param {string} roomId
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* @param {string[]} eventIds
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* @return {Function<Promise>}
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*/
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// performance comment from above refers to the fact that there *might*
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// be a correlation between event_id sorting order and chronology.
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// In that case we could avoid running over all eventIds, as the reported order by findExistingKeys
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// would match the order of eventIds. That's why findLast is also passed as backwards to keysExist.
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// also passing them in chronological order makes sense as that's how we'll receive them almost always.
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async findFirstOccurringEventId(roomId, eventIds) {
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const byEventId = this._timelineStore.index("byEventId");
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const keys = eventIds.map(eventId => encodeEventIdKey(roomId, eventId));
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const results = new Array(keys.length);
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let firstFoundKey;
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// find first result that is found and has no undefined results before it
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function firstFoundAndPrecedingResolved() {
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for(let i = 0; i < results.length; ++i) {
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if (results[i] === undefined) {
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return;
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} else if(results[i] === true) {
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return keys[i];
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}
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}
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}
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await byEventId.findExistingKeys(keys, false, (key, found) => {
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const index = keys.indexOf(key);
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results[index] = found;
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firstFoundKey = firstFoundAndPrecedingResolved();
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return !!firstFoundKey;
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});
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return firstFoundKey && decodeEventIdKey(firstFoundKey).eventId;
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}
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/** Inserts a new entry into the store. The combination of roomId and eventKey should not exist yet, or an error is thrown.
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* @param {Entry} entry the entry to insert
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* @return {Promise<>} a promise resolving to undefined if the operation was successful, or a StorageError if not.
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* @throws {StorageError} ...
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*/
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insert(entry) {
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entry.key = encodeKey(entry.roomId, entry.fragmentId, entry.eventIndex);
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entry.eventIdKey = encodeEventIdKey(entry.roomId, entry.event.event_id);
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// TODO: map error? or in idb/store?
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return this._timelineStore.add(entry);
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}
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/** Updates the entry into the store with the given [roomId, eventKey] combination.
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* If not yet present, will insert. Might be slower than add.
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* @param {Entry} entry the entry to update.
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* @return {Promise<>} a promise resolving to undefined if the operation was successful, or a StorageError if not.
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*/
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update(entry) {
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return this._timelineStore.put(entry);
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}
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get(roomId, eventKey) {
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return this._timelineStore.get(encodeKey(roomId, eventKey.fragmentId, eventKey.eventIndex));
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}
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// returns the entries as well!! (or not always needed? I guess not always needed, so extra method)
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removeRange(roomId, range) {
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// TODO: read the entries!
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return this._timelineStore.delete(range.asIDBKeyRange(roomId));
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}
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getByEventId(roomId, eventId) {
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return this._timelineStore.index("byEventId").get(encodeEventIdKey(roomId, eventId));
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}
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}
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