Added IndexedDB utility functions for reading and writing bookmarks

Summary:
These are utility function for reading from the IndexedDB and writing to it. This will be used for persistant storage of bookmarks.

The reason I chose IndexedDB over local storage is due to the poor efficiency of stringifying and parsing a long list of bookmarks everytime we read and write to local storage.

With IndexedDB we can modify a single value at a time.

Bookmarks are passed around as a Map, with the key being the uri's and the common names being the values. This allows me to check if a specified uri is in the Map in O(1) time, so that I can highlight the star icon in the UI with gold.

Reviewed By: jknoxville

Differential Revision: D16498744

fbshipit-source-id: 7c7af28bf4eb3fcc985a71dfd61ffbdb8481b6a6

flow-typed/indexedDB.js

@@ -0,0 +1,31 @@
+declare class DOMStringList {
+  +[key: number]: string;
+  +length: number;
+  item: number => string | null;
+  contains: string => boolean;
+}
+
+declare interface IDBDatabase extends EventTarget {
+  close(): void;
+  createObjectStore(
+    name: string,
+    options?: {
+      keyPath?: ?(string | string[]),
+      autoIncrement?: boolean,
+      ...
+    },
+  ): IDBObjectStore;
+  deleteObjectStore(name: string): void;
+  transaction(
+    storeNames: string | string[],
+    mode?: 'readonly' | 'readwrite' | 'versionchange',
+  ): IDBTransaction;
+  name: string;
+  version: number;
+  objectStoreNames: string[];
+  objectStoreNames: DOMStringList;
+  onabort: (e: any) => mixed;
+  onclose: (e: any) => mixed;
+  onerror: (e: any) => mixed;
+  onversionchange: (e: any) => mixed;
+}

src/plugins/navigation/util/indexedDB.js

@@ -0,0 +1,94 @@
+/**
+ * Copyright 2018-present Facebook.
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ * @format
+ * @flow strict-local
+ */
+
+import type {Bookmark} from '../';
+
+const FLIPPER_NAVIGATION_PLUGIN_DB = 'flipper_navigation_plugin_db';
+const FLIPPER_NAVIGATION_PLUGIN_DB_VERSION = 1;
+
+const BOOKMARKS_KEY = 'bookmarks';
+
+const createBookmarksObjectStore: IDBDatabase => Promise<void> = (
+  db: IDBDatabase,
+) => {
+  return new Promise((resolve, reject) => {
+    if (!db.objectStoreNames.contains(BOOKMARKS_KEY)) {
+      const bookmarksObjectStore = db.createObjectStore(BOOKMARKS_KEY, {
+        keyPath: 'uri',
+      });
+      bookmarksObjectStore.transaction.oncomplete = () => resolve();
+      bookmarksObjectStore.transaction.onerror = event =>
+        reject(event.target.error);
+    } else {
+      resolve();
+    }
+  });
+};
+
+const initializeNavigationPluginDB: IDBDatabase => Promise<Array<void>> = (
+  db: IDBDatabase,
+) => {
+  return Promise.all([createBookmarksObjectStore(db)]);
+};
+
+const openNavigationPluginDB: () => Promise<IDBDatabase> = () => {
+  return new Promise((resolve, reject) => {
+    const openRequest = window.indexedDB.open(
+      FLIPPER_NAVIGATION_PLUGIN_DB,
+      FLIPPER_NAVIGATION_PLUGIN_DB_VERSION,
+    );
+    openRequest.onupgradeneeded = () => {
+      const db = openRequest.result;
+      initializeNavigationPluginDB(db).then(() => resolve(db));
+    };
+    openRequest.onerror = event => reject(event.target.error);
+    openRequest.onsuccess = () => resolve(openRequest.result);
+  });
+};
+
+export const writeBookmarkToDB: Bookmark => Promise<void> = (
+  bookmark: Bookmark,
+) => {
+  return new Promise((resolve, reject) => {
+    openNavigationPluginDB()
+      .then((db: IDBDatabase) => {
+        const bookmarksObjectStore = db
+          .transaction(BOOKMARKS_KEY, 'readwrite')
+          .objectStore(BOOKMARKS_KEY);
+        const request = bookmarksObjectStore.put(bookmark);
+        request.onsuccess = () => resolve();
+        request.onerror = event => reject(event.target.error);
+      })
+      .catch(reject);
+  });
+};
+
+export const readBookmarksFromDB: () => Promise<Map<string, Bookmark>> = () => {
+  return new Promise((resolve, reject) => {
+    const bookmarks = new Map();
+    openNavigationPluginDB()
+      .then((db: IDBDatabase) => {
+        const bookmarksObjectStore = db
+          .transaction(BOOKMARKS_KEY)
+          .objectStore(BOOKMARKS_KEY);
+        bookmarksObjectStore.openCursor().onsuccess = event => {
+          const cursor = event.target.result;
+          if (cursor) {
+            const bookmark = cursor.value;
+            bookmarks.set(bookmark.uri, bookmark);
+            cursor.continue();
+          } else {
+            resolve(bookmarks);
+          }
+        };
+        bookmarksObjectStore.openCursor().onerror = event =>
+          reject(event.target.error);
+      })
+      .catch(reject);
+  });
+};