Fix upload cancel in e2e rooms

This is a bit of a mess of passing promises around - we weren't
taking the right promise to pass to cancelUpload.

Also e2e uploads take time to read into memory & encrypt, so allow
cancelling them during those phases too, even though we can't abort
those phases before they're done - we do mark the upload as cancelled
though so filter the current uploads for cancelled ones.

Fixes https://github.com/vector-im/riot-web/issues/4891

src/ContentMessages.js

@@ -34,6 +34,7 @@ import "blueimp-canvas-to-blob";
 const MAX_WIDTH = 800;
 const MAX_HEIGHT = 600;
 
+export class UploadCancelledError extends Error {}
 
 /**
  * Create a thumbnail for a image DOM element.
@@ -236,17 +237,25 @@ function uploadFile(matrixClient, roomId, file, progressHandler) {
     if (matrixClient.isRoomEncrypted(roomId)) {
         // If the room is encrypted then encrypt the file before uploading it.
         // First read the file into memory.
-        return readFileAsArrayBuffer(file).then(function(data) {
+        let cancelled = false;
+        let uploadPromise;
+        let encryptInfo;
+        const prom = readFileAsArrayBuffer(file).then(function(data) {
+            if (cancelled) throw new UploadCancelledError();
             // Then encrypt the file.
             return encrypt.encryptAttachment(data);
         }).then(function(encryptResult) {
+            if (cancelled) throw new UploadCancelledError();
             // Record the information needed to decrypt the attachment.
-            const encryptInfo = encryptResult.info;
+            encryptInfo = encryptResult.info;
             // Pass the encrypted data as a Blob to the uploader.
             const blob = new Blob([encryptResult.data]);
-            return matrixClient.uploadContent(blob, {
+            uploadPromise = matrixClient.uploadContent(blob, {
                 progressHandler: progressHandler,
                 includeFilename: false,
+            });
+
+            return uploadPromise;
         }).then(function(url) {
             // If the attachment is encrypted then bundle the URL along
             // with the information needed to decrypt the attachment and
@@ -257,7 +266,11 @@ function uploadFile(matrixClient, roomId, file, progressHandler) {
             }
             return {"file": encryptInfo};
         });
-        });
+        prom.abort = () => {
+            cancelled = true;
+            if (uploadPromise) MatrixClientPeg.get().cancelUpload(uploadPromise);
+        };
+        return prom;
     } else {
         const basePromise = matrixClient.uploadContent(file, {
             progressHandler: progressHandler,
@@ -513,7 +526,7 @@ export default class ContentMessages {
     }
 
     getCurrentUploads() {
-        return this.inprogress;
+        return this.inprogress.filter(u => !u.canceled);
     }
 
     cancelUpload(promise) {
@@ -529,6 +542,7 @@ export default class ContentMessages {
         if (upload) {
             upload.canceled = true;
             MatrixClientPeg.get().cancelUpload(upload.promise);
+            dis.dispatch({action: 'upload_canceled', upload});
         }
     }
 }

src/components/structures/RoomView.js

@@ -543,6 +543,7 @@ module.exports = React.createClass({
             case 'notifier_enabled':
             case 'upload_started':
             case 'upload_finished':
+            case 'upload_canceled':
                 this.forceUpdate();
                 break;
             case 'call_state':

src/components/structures/UploadBar.js

@@ -16,7 +16,7 @@ limitations under the License.
 
 const React = require('react');
 import PropTypes from 'prop-types';
-const ContentMessages = require('../../ContentMessages');
+import ContentMessages from '../../ContentMessages';
 const dis = require('../../dispatcher');
 const filesize = require('filesize');
 import { _t } from '../../languageHandler';
@@ -40,6 +40,7 @@ module.exports = React.createClass({displayName: 'UploadBar',
         switch (payload.action) {
             case 'upload_progress':
             case 'upload_finished':
+            case 'upload_canceled':
             case 'upload_failed':
                 if (this.mounted) this.forceUpdate();
                 break;