draft of AttachmentUpload class

src/matrix/room/AttachmentUpload.js

@@ -0,0 +1,94 @@
+/*
+Copyright 2020 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import {encryptAttachment} from "../e2ee/attachment.js";
+
+export class AttachmentUpload {
+    constructor({filename, blob, hsApi, platform, isEncrypted}) {
+        this._filename = filename;
+        this._unencryptedBlob = blob;
+        this._isEncrypted = isEncrypted;
+        this._platform = platform;
+        this._hsApi = hsApi;
+        this._mxcUrl = null;
+        this._transferredBlob = null;
+        this._encryptionInfo = null;
+        this._uploadPromise = null;
+        this._uploadRequest = null;
+        this._aborted = false;
+    }
+
+    upload() {
+        if (!this._uploadPromise) {
+            this._uploadPromise = this._upload();
+        }
+        return this._uploadPromise;
+    }
+
+    async _upload() {
+        let transferredBlob = this._unencryptedBlob;
+        if (this.isEncrypted) {
+            const {info, blob} = await encryptAttachment(this._platform, this._unencryptedBlob);
+            transferredBlob = blob;
+            this._encryptionInfo = info;
+        }
+        if (this._aborted) {
+            return;
+        }
+        this._uploadRequest = this._hsApi.uploadAttachment(transferredBlob, this._filename);
+        const {content_uri} = await this._uploadRequest.response();
+        this._mxcUrl = content_uri;
+        this._transferredBlob = transferredBlob;
+    }
+
+    /** @public */
+    abort() {
+        this._aborted = true;
+        this._uploadRequest?.abort();
+    }
+
+    /** @public */
+    get localPreview() {
+        return this._unencryptedBlob;
+    }
+
+    /** @package */
+    uploaded() {
+        if (!this._uploadPromise) {
+            throw new Error("upload has not started yet");
+        }
+        return this._uploadPromise;
+    }
+
+    /** @package */
+    applyToContent(content) {
+        if (!this._mxcUrl) {
+            throw new Error("upload has not finished");
+        }
+        content.info = {
+            size: this._transferredBlob.size,
+            mimetype: this._unencryptedBlob.mimeType,
+        };
+        if (this._isEncrypted) {
+            content.file = Object.assign(this._encryptionInfo, {
+                mimetype: this._unencryptedBlob.mimeType,
+                url: this._mxcUrl
+            });
+        } else {
+            content.url = this._mxcUrl;
+        }
+    }
+}