From 974d8d92416da928704163b13f3c50f3a0d1392a Mon Sep 17 00:00:00 2001
From: Abhinav-grd <abhinavk.grd@gmail.com>
Date: Sun, 29 Aug 2021 14:58:53 +0530
Subject: [PATCH] store file promise in fileObjectUrlPromise

---
 src/services/downloadManager.ts | 48 +++++++++------------------------
 src/utils/file/index.ts         | 23 +++++++++++++++-
 2 files changed, 34 insertions(+), 37 deletions(-)

diff --git a/src/services/downloadManager.ts b/src/services/downloadManager.ts
index c4bd3c15f..af2c72e92 100644
--- a/src/services/downloadManager.ts
+++ b/src/services/downloadManager.ts
@@ -1,20 +1,13 @@
 import { getToken } from 'utils/common/key';
 import { getFileUrl, getThumbnailUrl } from 'utils/common/apiUtil';
 import CryptoWorker from 'utils/crypto';
-import {
-    fileIsHEIC,
-    convertHEIC2JPEG,
-    fileNameWithoutExtension,
-    generateStreamFromArrayBuffer,
-} from 'utils/file';
+import { generateStreamFromArrayBuffer, convertForPreview } from 'utils/file';
 import HTTPService from './HTTPService';
 import { File, FILE_TYPE } from './fileService';
 import { logError } from 'utils/sentry';
-import { decodeMotionPhoto } from './motionPhotoService';
-import { getMimeTypeFromBlob } from './upload/readFileService';
 
 class DownloadManager {
-    private fileDownloads = new Map<string, string>();
+    private fileObjectUrlPromise = new Map<string, Promise<string>>();
     private thumbnailObjectUrlPromise = new Map<number, Promise<string>>();
 
     public async getPreview(file: File) {
@@ -75,40 +68,23 @@ class DownloadManager {
 
     getFile = async (file: File, forPreview = false) => {
         try {
-            if (!this.fileDownloads.get(`${file.id}_${forPreview}`)) {
-                // unzip motion photo and return fileBlob of the image for preview
+            const getFilePromise = (async () => {
                 const fileStream = await this.downloadFile(file);
                 let fileBlob = await new Response(fileStream).blob();
                 if (forPreview) {
-                    if (file.metadata.fileType === FILE_TYPE.LIVE_PHOTO) {
-                        const originalName = fileNameWithoutExtension(
-                            file.metadata.title
-                        );
-                        const motionPhoto = await decodeMotionPhoto(
-                            fileBlob,
-                            originalName
-                        );
-                        fileBlob = new Blob([motionPhoto.image]);
-                    }
-
-                    const typeFromExtension =
-                        file.metadata.title.split('.')[-1];
-                    const worker = await new CryptoWorker();
-
-                    const mimeType =
-                        (await getMimeTypeFromBlob(worker, fileBlob)) ??
-                        typeFromExtension;
-
-                    if (fileIsHEIC(mimeType)) {
-                        fileBlob = await convertHEIC2JPEG(fileBlob);
-                    }
+                    fileBlob = await convertForPreview(file, fileBlob);
                 }
-                this.fileDownloads.set(
+                return URL.createObjectURL(fileBlob);
+            })();
+            if (!this.fileObjectUrlPromise.get(`${file.id}_${forPreview}`)) {
+                this.fileObjectUrlPromise.set(
                     `${file.id}_${forPreview}`,
-                    URL.createObjectURL(fileBlob)
+                    getFilePromise
                 );
             }
-            return this.fileDownloads.get(`${file.id}_${forPreview}`);
+            return await this.fileObjectUrlPromise.get(
+                `${file.id}_${forPreview}`
+            );
         } catch (e) {
             logError(e, 'Failed to get File');
         }
diff --git a/src/utils/file/index.ts b/src/utils/file/index.ts
index 0ba886f78..ccdbcac5e 100644
--- a/src/utils/file/index.ts
+++ b/src/utils/file/index.ts
@@ -1,5 +1,7 @@
 import { Collection } from 'services/collectionService';
-import { File } from 'services/fileService';
+import { File, FILE_TYPE } from 'services/fileService';
+import { decodeMotionPhoto } from 'services/motionPhotoService';
+import { getMimeTypeFromBlob } from 'services/upload/readFileService';
 import { runningInBrowser } from 'utils/common';
 import CryptoWorker from 'utils/crypto';
 
@@ -175,3 +177,22 @@ export function generateStreamFromArrayBuffer(data: Uint8Array) {
         },
     });
 }
+
+export async function convertForPreview(file: File, fileBlob: Blob) {
+    if (file.metadata.fileType === FILE_TYPE.LIVE_PHOTO) {
+        const originalName = fileNameWithoutExtension(file.metadata.title);
+        const motionPhoto = await decodeMotionPhoto(fileBlob, originalName);
+        fileBlob = new Blob([motionPhoto.image]);
+    }
+
+    const typeFromExtension = file.metadata.title.split('.')[-1];
+    const worker = await new CryptoWorker();
+
+    const mimeType =
+        (await getMimeTypeFromBlob(worker, fileBlob)) ?? typeFromExtension;
+
+    if (fileIsHEIC(mimeType)) {
+        fileBlob = await convertHEIC2JPEG(fileBlob);
+    }
+    return fileBlob;
+}