WIP

doc/GOAL.md

@@ -3,3 +3,6 @@ goal:
 write client that works on lumia 950 phone, so I can use matrix on my phone.
 
 try approach offline to indexeddb. go low-memory, and test the performance of storing every event individually in indexeddb.
+
+try to use little bandwidth, mainly by being an offline application and storing all requested data in indexeddb.
+be as functional as possible while offline

src/matrix/error.js

@@ -4,6 +4,12 @@ export class HomeServerError extends Error {
         this.errcode = body.errcode;
         this.retry_after_ms = body.retry_after_ms;
     }
+
+    get isFatal() {
+        switch (this.errcode) {
+            
+        }
+    }
 }
 
 export class RequestAbortError extends Error {

src/matrix/room/sending/PendingEvent.js

@@ -1,13 +1,11 @@
 export default class PendingEvent {
-    static fromRedaction(eventId) {
-
+    constructor(roomId, queueIndex, eventType, content, txnId) {
+        this._roomId = roomId;
+        this._eventType = eventType;
+        this._content = content;
+        this._txnId = txnId;
+        this._queueIndex = queueIndex;
     }
 
-    static fromContent(content) {
 
-    }
-
-    static fromStateKey(eventType, stateKey, content) {
-        
-    }
 }

src/matrix/room/sending/SendQueue.js

@@ -1,81 +1,124 @@
-class Sender {
-    constructor({hsApi}) {
+import Platform from "../../../Platform.js";
+
+class RateLimitingBackoff {
+    constructor() {
+        this._remainingRateLimitedRequest = 0;
+    }
+
+    async waitAfterLimitExceeded(retryAfterMs) {
+        // this._remainingRateLimitedRequest = 5;
+        // if (typeof retryAfterMs !== "number") {
+        // } else {
+        // }
+        if (!retryAfterMs) {
+            retryAfterMs = 5000;
+        }
+        await Platform.delay(retryAfterMs);
+    }
+
+    // do we have to know about succeeding requests?
+    // we can just 
+
+    async waitForNextSend() {
+        // this._remainingRateLimitedRequest = Math.max(0, this._remainingRateLimitedRequest - 1);
+        Platform.delay(1000);
+    }
+}
+
+class SendScheduler {
+    constructor({hsApi, backoff}) {
         this._hsApi = hsApi;
         this._slotRequests = [];
         this._sendScheduled = false;
         this._offline = false;
         this._waitTime = 0;
+        this._backoff = backoff;
     }
 
     // this should really be per roomId to avoid head-of-line blocking
-    acquireSlot() {
+    // 
+    // takes a callback instead of returning a promise with the slot
+    // to make sure the scheduler doesn't get blocked by a slot that is not consumed
+    runSlot(slotCallback) {
         let request;
-        const promise = new Promise((resolve) => request = {resolve});
+        const promise = new Promise((resolve, reject) => request = {resolve, reject, slotCallback});
         this._slotRequests.push(request);
-        if (!this._sendScheduled) {
-            this._startNextSlot();
+        if (!this._sendScheduled && !this._offline) {
+            this._sendLoop();
         }
         return promise;
     }
 
-    async _startNextSlot() {
-        if (this._waitTime !== 0) {
-            await Platform.delay(this._waitTime);
-        }
+    async _sendLoop() {
+        while (this._slotRequests.length) {
             const request = this._slotRequests.unshift();
-        this._currentSlot = new SenderSlot(this);
-        request.resolve(this._currentSlot);
+            this._currentSlot = new SendSlot(this);
+            // this can throw!
+            let result;
+            try {
+                result = await request.slotCallback(this._currentSlot);
+            } catch (err) {
+                if (err instanceof NetworkError) {
+                    // we're offline, everybody will have
+                    // to re-request slots when we come back online
+                    this._offline = true;
+                    for (const r of this._slotRequests) {
+                        r.reject(err);
+                    }
+                    this._slotRequests = [];
+                }
+                request.reject(err);
+                break;
+            }
+            request.resolve(result);
+        }
+        // do next here instead of in _doSend
     }
 
-    _discardSlot(slot) {
-        if (slot === this._currentSlot) {
-            this._currentSlot = null;
-            this._sendScheduled = true;
-            Promise.resolve().then(() => this._startNextSlot());
-        }
-    }
-
-    async _doSend(slot, callback) {
+    async _doSend(slot, sendCallback) {
         this._sendScheduled = false;
         if (slot !== this._currentSlot) {
-            throw new Error("slot is not active");
+            throw new Error("Slot is not active");
         }
-        try {
+        await this._backoff.waitForNextSend();
         // loop is left by return or throw
-            while(true) {
+        while (true) { // eslint-disable-line no-constant-condition
             try {
-                    return await callback(this._hsApi);
+                return await sendCallback(this._hsApi);
             } catch (err) {
                 if (err instanceof HomeServerError && err.errcode === "M_LIMIT_EXCEEDED") {
-                        await Platform.delay(err.retry_after_ms);
+                    await this._backoff.waitAfterLimitExceeded(err.retry_after_ms);
                 } else {
                     throw err;
                 }
             }
         }
-        } catch (err) {
-            if (err instanceof NetworkError) {
-                this._offline = true;
-                // went offline, probably want to notify SendQueues somehow
-            }
-            throw err;
-        } finally {
-            this._currentSlot = null;
-            if (!this._offline && this._slotRequests.length) {
-                this._sendScheduled = true;
-                Promise.resolve().then(() => this._startNextSlot());
-            }
-        }
     }
 }
 
-class SenderSlot {
-    constructor(sender) {
-        this._sender = sender;
+/*
+this represents a slot to do one rate limited api call.
+because rate-limiting is handled here, it should only
+try to do one call, so the SendScheduler can safely
+retry if the call ends up being rate limited.
+This is also why we have this abstraction it hsApi is not
+passed straight to SendQueue when it is its turn to send.
+e.g. we wouldn't want to repeat the callback in SendQueue that could
+have other side-effects before the call to hsApi that we wouldn't want
+repeated (setting up progress handlers for file uploads,
+... a UI update to say it started sending?
+ ... updating storage would probably only happen once the call succeeded
+ ... doing multiple hsApi calls for e.g. a file upload before sending a image message (they should individually be retried)
+) maybe it is a bit overengineering, but lets stick with it for now.
+At least the above is a clear definition why we have this class
+*/
+class SendSlot {
+    constructor(scheduler) {
+        this._scheduler = scheduler;
     }
 
-    sendEvent(pendingEvent) {
-        return this._sender._doSend(this, async hsApi => {
+    sendContentEvent(pendingEvent) {
+        return this._scheduler._doSend(this, async hsApi => {
             const request = hsApi.send(
                 pendingEvent.roomId,
                 pendingEvent.eventType,
@@ -87,11 +130,76 @@ class SenderSlot {
         });
     }
 
-    discard() {
-        this._sender._discardSlot(this);
+    sendRedaction(pendingEvent) {
+        return this._scheduler._doSend(this, async hsApi => {
+            const request = hsApi.redact(
+                pendingEvent.roomId,
+                pendingEvent.redacts,
+                pendingEvent.txnId,
+                pendingEvent.reason
+            );
+            const response = await request.response();
+            return response.event_id;
+        });
+    }
+
+    // progressCallback should report the amount of bytes sent
+    uploadMedia(fileName, contentType, blob, progressCallback) {
+
     }
 }
 
-export default class SendQueue {
-    constructor({sender})
+function makeTxnId() {
+    const n = Math.floor(Math.random() * Number.MAX_SAFE_INTEGER);
+    const str = n.toString(16);
+    return "t" + "0".repeat(14 - str.length) + str;
+}
+
+export default class SendQueue {
+    constructor({roomId, storage, scheduler, pendingEvents}) {
+        this._roomId = roomId;
+        this._storage = storage;
+        this._scheduler = scheduler;
+        this._pendingEvents = pendingEvents.map(d => PendingEvent.fromData(d));
+    }
+
+    async _sendLoop() {
+        let pendingEvent = null;
+        // eslint-disable-next-line no-cond-assign
+        while (pendingEvent = await this._nextPendingEvent()) {
+            // const mxcUrl = await this._scheduler.runSlot(slot => {
+            //     return slot.uploadMedia(fileName, contentType, blob, bytesSent => {
+            //         pendingEvent.updateAttachmentUploadProgress(bytesSent);
+            //     });
+            // });
+
+            // pendingEvent.setAttachmentUrl(mxcUrl);
+            //update storage for pendingEvent after updating url,
+            //remove blob only later to keep preview?
+
+            await this._scheduler.runSlot(slot => {
+                if (pendingEvent.isRedaction) {
+                    return slot.sendRedaction(pendingEvent);
+                } else if (pendingEvent.isContentEvent) {
+                    return slot.sendContentEvent(pendingEvent);
+                }
+            });
+        }
+    }
+
+    async enqueueEvent(eventType, content) {
+        // temporary
+        const txn = await this._storage.readWriteTxn([this._storage.storeNames.pendingEvents]);
+        const pendingEventsStore = txn.pendingEvents;
+        const maxQueueIndex = await pendingEventsStore.getMaxQueueIndex(this._roomId) || 0;
+        const queueIndex = maxQueueIndex + 1;
+        const pendingEvent = new PendingEvent(this._roomId, queueIndex, eventType, content, makeTxnId());
+        pendingEventsStore.add(pendingEvent.data);
+        await txn.complete();
+        // create txnId
+        // create queueOrder
+        // store event
+        // if online and not running send loop
+            // start sending loop
+    }
 }

src/matrix/storage/common.js

@@ -1,4 +1,11 @@
-export const STORE_NAMES = Object.freeze(["session", "roomState", "roomSummary", "timelineEvents", "timelineFragments"]);
+export const STORE_NAMES = Object.freeze([
+    "session",
+    "roomState",
+    "roomSummary",
+    "timelineEvents",
+    "timelineFragments",
+    "pendingEvents",
+]);
 
 export const STORE_MAP = Object.freeze(STORE_NAMES.reduce((nameMap, name) => {
     nameMap[name] = name;

src/matrix/storage/idb/create.js

@@ -20,6 +20,7 @@ function createStores(db) {
     timelineEvents.createIndex("byEventId", "eventIdKey", {unique: true});
     //key = room_id | event.type | event.state_key,
     db.createObjectStore("roomState", {keyPath: "key"});
+    db.createObjectStore("pendingEvents", {keyPath: "key"});
     
     // const roomMembers = db.createObjectStore("roomMembers", {keyPath: [
     //  "event.room_id",

src/matrix/storage/idb/query-target.js

@@ -71,6 +71,16 @@ export default class QueryTarget {
         return this._find(range, predicate, "prev");
     }
 
+    async findMaxKey(range) {
+        const cursor = this._target.openKeyCursor(range, "prev");
+        let maxKey;
+        await iterateCursor(cursor, (_, key) => {
+            maxKey = key;
+            return {done: true};
+        });
+        return maxKey;
+    }
+
     /**
      * Checks if a given set of keys exist.
      * Calls `callback(key, found)` for each key in `keys`, in key sorting order (or reversed if backwards=true).

src/matrix/storage/idb/stores/PendingEventStore.js

@@ -0,0 +1,44 @@
+import { encodeUint32, decodeUint32 } from "../utils.js";
+import Platform from "../../../../Platform.js";
+
+function encodeKey(roomId, queueIndex) {
+    return `${roomId}|${encodeUint32(queueIndex)}`;
+}
+
+function decodeKey(key) {
+    const [roomId, encodedQueueIndex] = key.split("|");
+    const queueIndex = decodeUint32(encodedQueueIndex);
+    return {roomId, queueIndex};
+}
+
+export default class PendingEventStore {
+    constructor(eventStore) {
+        this._eventStore = eventStore;
+    }
+
+    async getMaxQueueIndex(roomId) {
+        const range = IDBKeyRange.bound(
+            encodeKey(roomId, Platform.minStorageKey),
+            encodeKey(roomId, Platform.maxStorageKey),
+            false,
+            false,
+        );
+        const maxKey = await this._eventStore.findMaxKey(range);
+        if (maxKey) {
+            return decodeKey(maxKey).queueIndex;
+        }
+    }
+
+    add(pendingEvent) {
+        pendingEvent.key = encodeKey(pendingEvent.roomId, pendingEvent.queueIndex);
+        return this._eventStore.add(pendingEvent);
+    }
+
+    update(pendingEvent) {
+        return this._eventStore.put(pendingEvent);
+    }
+
+    getAllEvents() {
+        return this._eventStore.selectAll();
+    }
+}

src/matrix/storage/idb/stores/TimelineEventStore.js

@@ -1,13 +1,8 @@
 import EventKey from "../../../room/timeline/EventKey.js";
 import { StorageError } from "../../common.js";
+import { encodeUint32 } from "../utils.js";
 import Platform from "../../../../Platform.js";
 
-// storage keys are defined to be unsigned 32bit numbers in WebPlatform.js, which is assumed by idb
-function encodeUint32(n) {
-    const hex = n.toString(16);
-    return "0".repeat(8 - hex.length) + hex;
-}
-
 function encodeKey(roomId, fragmentId, eventIndex) {
     return `${roomId}|${encodeUint32(fragmentId)}|${encodeUint32(eventIndex)}`;
 }

src/matrix/storage/idb/stores/TimelineFragmentStore.js

@@ -1,10 +1,9 @@
 import { StorageError } from "../../common.js";
 import Platform from "../../../../Platform.js";
+import { encodeUint32 } from "../utils.js";
 
 function encodeKey(roomId, fragmentId) {
-    let fragmentIdHex = fragmentId.toString(16);
-    fragmentIdHex = "0".repeat(8 - fragmentIdHex.length) + fragmentIdHex;
-    return `${roomId}|${fragmentIdHex}`;
+    return `${roomId}|${encodeUint32(fragmentId)}`;
 }
 
 export default class RoomFragmentStore {

src/matrix/storage/idb/utils.js

@@ -1,5 +1,16 @@
 import { StorageError } from "../common.js";
 
+
+// storage keys are defined to be unsigned 32bit numbers in WebPlatform.js, which is assumed by idb
+export function encodeUint32(n) {
+    const hex = n.toString(16);
+    return "0".repeat(8 - hex.length) + hex;
+}
+
+export function decodeUint32(str) {
+    return parseInt(str, 16);
+}
+
 export function openDatabase(name, createObjectStore, version) {
     const req = window.indexedDB.open(name, version);
     req.onupgradeneeded = (ev) => {

src/observable/list/ObservableArray.js

@@ -1,9 +1,9 @@
 import BaseObservableList from "./BaseObservableList.js";
 
 export default class ObservableArray extends BaseObservableList {
-    constructor() {
+    constructor(initialValues = []) {
         super();
-        this._items = [];
+        this._items = initialValues;
     }
 
     append(item) {