Add close button to the export share sheet

Summary: Adds close button to the dialog box which appears while exporting a flipper trace. To implement this I had to first see what is the bottle neck of the export process. The major bottle neck turned out to be the serialization step. So to make the export process interruptible, I have put in a call `await idler.idle()` which resolves when the main thread is idle. I have also added the tests for the idler.

Reviewed By: passy

Differential Revision: D16183582

fbshipit-source-id: 4ec0c985e216fd9d41e91cdcd8b4cca66d2cb04d

src/utils/exportData.js

@@ -25,7 +25,7 @@ import {readCurrentRevision} from './packageMetadata.js';
 import {tryCatchReportPlatformFailures} from './metrics';
 import {promisify} from 'util';
 import promiseTimeout from './promiseTimeout';
-
+import {Idler} from './Idler';
 export const IMPORT_FLIPPER_TRACE_EVENT = 'import-flipper-trace';
 export const EXPORT_FLIPPER_TRACE_EVENT = 'export-flipper-trace';
 
@@ -266,14 +266,12 @@ export async function getStoreExport(
   plugins.devicePlugins.forEach((val, key) => {
     pluginsMap.set(key, val);
   });
-
   const metadata = await fetchMetadata(pluginStates, pluginsMap, store);
   const {errorArray} = metadata;
   const newPluginState = metadata.pluginStates;
 
   const {activeNotifications} = store.getState().notifications;
   const {devicePlugins} = store.getState().plugins;
-
   const exportData = await processStore(
     activeNotifications,
     selectedDevice,
@@ -287,6 +285,7 @@ export async function getStoreExport(
 
 export function exportStore(
   store: MiddlewareAPI,
+  idler?: Idler,
 ): Promise<{serializedString: string, errorArray: Array<Error>}> {
   getLogger().track('usage', EXPORT_FLIPPER_TRACE_EVENT);
   return new Promise(async (resolve, reject) => {
@@ -296,11 +295,15 @@ export function exportStore(
         console.error('Make sure a device is connected');
         reject(new Error('No device is selected'));
       }
-      const serializedString = serialize(exportData);
-      if (serializedString.length <= 0) {
-        reject(new Error('Serialize function returned empty string'));
+      try {
+        const serializedString = await serialize(exportData, idler);
+        if (serializedString.length <= 0) {
+          reject(new Error('Serialize function returned empty string'));
+        }
+        resolve({serializedString, errorArray});
+      } catch (e) {
+        reject(e);
       }
-      resolve({serializedString, errorArray});
     } catch (e) {
       reject(e);
     }
@@ -310,8 +313,9 @@ export function exportStore(
 export const exportStoreToFile = (
   exportFilePath: string,
   store: Store,
+  idler?: Idler,
 ): Promise<{errorArray: Array<Error>}> => {
-  return exportStore(store).then(({serializedString, errorArray}) => {
+  return exportStore(store, idler).then(({serializedString, errorArray}) => {
     return promisify(fs.writeFile)(exportFilePath, serializedString).then(
       () => {
         return {errorArray};