WIP

doc/SENDING.md

@@ -76,7 +76,35 @@ steps of sending
     // sender is the thing that is shared across rooms to handle rate limiting.
     const sendQueue = new SendQueue({roomId, hsApi, sender, storage});
     await sendQueue.load();     //loads the queue?
-                                //might need to load members for e2e rooms
+                                //might need to load members for e2e rooms ...
+                                //events should be encrypted before storing them though ...
+ 
+
+    // terminology ...?
+    // task: to let us wait for it to be our turn
+    // given rate limiting
+    class Sender {
+        acquireSlot() {
+            return new SendSlot();
+        }
+    }
+    // terminology ...?
+    // task: after waiting for it to be our turn given rate-limiting,
+    // send the actual thing we want to send.
+    // this should be used for all rate-limited apis... ? 
+    class SendSlot {
+        sendContent(content) {
+
+        }
+
+        sendRedaction() {
+
+        }
+
+        uploadMedia() {
+
+        }
+    }
 
     class SendQueue {
         // when trying to send
@@ -93,11 +121,13 @@ steps of sending
             while (let pendingEvent = await findNextPendingEvent()) {
                 pendingEvent.status = QUEUED;
                 try {
-                    await this.sender.sendEvent(() => {
+                    const mediaSlot = await this.sender.acquireSlot();
-                        // callback gets called
+                    const mxcUrl = await mediaSlot.uploadMedia(pendingEvent.blob);
+                    pendingEvent.content.url = mxcUrl;
+                    const contentSlot = await this.sender.acquireSlot();
+                    contentSlot.sendContent(pendingEvent.content);
                     pendingEvent.status = SENDING;
-                        return pendingEvent;
+                    await slot.sendContent(...);
-                    });
                 } catch (err) {
                     //offline
                 }

src/matrix/error.js

@@ -2,6 +2,7 @@ export class HomeServerError extends Error {
     constructor(method, url, body) {
         super(`${body.error} on ${method} ${url}`);
         this.errcode = body.errcode;
+        this.retry_after_ms = body.retry_after_ms;
     }
 }
 

src/matrix/room/sending/PendingEvent.js

@@ -0,0 +1,13 @@
+export default class PendingEvent {
+    static fromRedaction(eventId) {
+
+    }
+
+    static fromContent(content) {
+
+    }
+
+    static fromStateKey(eventType, stateKey, content) {
+        
+    }
+}

src/matrix/room/sending/SendQueue.js

@@ -0,0 +1,97 @@
+class Sender {
+    constructor({hsApi}) {
+        this._hsApi = hsApi;
+        this._slotRequests = [];
+        this._sendScheduled = false;
+        this._offline = false;
+        this._waitTime = 0;
+    }
+
+    // this should really be per roomId to avoid head-of-line blocking
+    acquireSlot() {
+        let request;
+        const promise = new Promise((resolve) => request = {resolve});
+        this._slotRequests.push(request);
+        if (!this._sendScheduled) {
+            this._startNextSlot();
+        }
+        return promise;
+    }
+
+    async _startNextSlot() {
+        if (this._waitTime !== 0) {
+            await Platform.delay(this._waitTime);
+        }
+        const request = this._slotRequests.unshift();
+        this._currentSlot = new SenderSlot(this);
+        request.resolve(this._currentSlot);
+    }
+
+    _discardSlot(slot) {
+        if (slot === this._currentSlot) {
+            this._currentSlot = null;
+            this._sendScheduled = true;
+            Promise.resolve().then(() => this._startNextSlot());
+        }
+    }
+
+    async _doSend(slot, callback) {
+        this._sendScheduled = false;
+        if (slot !== this._currentSlot) {
+            throw new Error("slot is not active");
+        }
+        try {
+            // loop is left by return or throw
+            while(true) {
+                try {
+                    return await callback(this._hsApi);
+                } catch (err) {
+                    if (err instanceof HomeServerError && err.errcode === "M_LIMIT_EXCEEDED") {
+                        await Platform.delay(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;
+    }
+
+    sendEvent(pendingEvent) {
+        return this._sender._doSend(this, async hsApi => {
+            const request = hsApi.send(
+                pendingEvent.roomId,
+                pendingEvent.eventType,
+                pendingEvent.txnId,
+                pendingEvent.content
+            );
+            const response = await request.response();
+            return response.event_id;
+        });
+    }
+
+    discard() {
+        this._sender._discardSlot(this);
+    }
+}
+
+export default class SendQueue {
+    constructor({sender})
+}

src/ui/web/WebPlatform.js

@@ -13,4 +13,8 @@ export default {
         // for indexeddb, we use unsigned 32 bit integers as keys
         return 0xFFFFFFFF;
     },
+
+    delay(ms) {
+        return new Promise(resolve => setTimeout(resolve, ms));
+    }
 }