Enable / Disable iOS support depending on xcode-select

Summary:
Queries xcode-select on ios dispatcher startup, to see if it's installed.
If it is, carry on with the ios device tracking, if not, don't bother.

This should stop it from emitting errors trying to track devices when things aren't installed.

I think it should also stop those install prompts from popping up.

Sets it in app state so we can tell the user about it, and maybe gate some other things too.

Reviewed By: passy

Differential Revision: D17830696

fbshipit-source-id: 960d09a9c5267afabf5e5e222379a0a7ed2cc444

src/dispatcher/iOSDevice.tsx

@@ -7,6 +7,7 @@
 
 import {ChildProcess} from 'child_process';
 import {Store} from '../reducers/index';
+import {setXcodeDetected} from '../reducers/application';
 import {Logger} from '../fb-interfaces/Logger';
 import {DeviceType} from '../devices/BaseDevice';
 import {promisify} from 'util';
@@ -150,7 +151,7 @@ function getActiveDevices(): Promise<Array<IOSDeviceParams>> {
 }
 
 function queryDevicesForever(store: Store, logger: Logger) {
-  queryDevices(store, logger)
+  return queryDevices(store, logger)
     .then(() => {
       // It's important to schedule the next check AFTER the current one has completed
       // to avoid simultaneous queries which can cause multiple user input prompts.
@@ -189,6 +190,12 @@ async function checkXcodeVersionMismatch() {
   }
 }
 
+async function isXcodeDetected(): Promise<boolean> {
+  return promisify(child_process.exec)('xcode-select -p')
+    .then(_ => true)
+    .catch(_ => false);
+}
+
 export async function getActiveDevicesAndSimulators(): Promise<
   Array<IOSDevice>
 > {
@@ -208,5 +215,12 @@ export default (store: Store, logger: Logger) => {
   if (process.platform !== 'darwin') {
     return;
   }
-  queryDevicesForever(store, logger);
+  isXcodeDetected()
+    .then(isDetected => {
+      store.dispatch(setXcodeDetected(isDetected));
+      return isDetected;
+    })
+    .then(isDetected =>
+      isDetected ? queryDevicesForever(store, logger) : Promise.resolve(),
+    );
 };

src/reducers/application.tsx

@@ -76,6 +76,7 @@ export type State = {
   launcherMsg: LauncherMsg;
   flipperRating: number | null;
   statusMessages: Array<string>;
+  xcodeCommandLineToolsDetected: boolean;
 };
 
 type BooleanActionType =
@@ -140,6 +141,12 @@ export type Action =
   | {
       type: 'REMOVE_STATUS_MSG';
       payload: {msg: string; sender: string};
+    }
+  | {
+      type: 'SET_XCODE_DETECTED';
+      payload: {
+        isDetected: boolean;
+      };
     };
 
 export const initialState: () => State = () => ({
@@ -161,6 +168,7 @@ export const initialState: () => State = () => ({
   },
   flipperRating: null,
   statusMessages: [],
+  xcodeCommandLineToolsDetected: false,
 });
 
 function statusMessage(sender: string, msg: string): string {
@@ -268,6 +276,8 @@ export default function reducer(
       return {...state, statusMessages};
     }
     return state;
+  } else if (action.type === 'SET_XCODE_DETECTED') {
+    return {...state, xcodeCommandLineToolsDetected: action.payload.isDetected};
   } else {
     return state;
   }
@@ -345,3 +355,8 @@ export const removeStatusMessage = (payload: StatusMessageType): Action => ({
   type: 'REMOVE_STATUS_MSG',
   payload,
 });
+
+export const setXcodeDetected = (isDetected: boolean): Action => ({
+  type: 'SET_XCODE_DETECTED',
+  payload: {isDetected},
+});

src/utils/listDevices.tsx

@@ -10,7 +10,13 @@ import BaseDevice from '../devices/BaseDevice';
 import {Store} from '../reducers/index';
 
 export async function listDevices(store: Store): Promise<Array<BaseDevice>> {
-  const androidDevices = await getActiveAndroidDevices(store);
-  const iOSDevices: BaseDevice[] = await getActiveDevicesAndSimulators();
-  return iOSDevices.concat(androidDevices);
+  const state = store.getState();
+  const androidDevices = state.settingsState.enableAndroid
+    ? await getActiveAndroidDevices(store)
+    : [];
+  const iOSDevices: BaseDevice[] = state.application
+    .xcodeCommandLineToolsDetected
+    ? await getActiveDevicesAndSimulators()
+    : [];
+  return [...androidDevices, ...iOSDevices];
 }