Show a message if a background plugin is not starred

Summary:
Since background plugins don't receive data anymore when not starred, we should hint the user about this.

For this diff, I reused the existing statusbar. Although this solution is quite ugly, I think it is better than introducing yet another notification / warning mechanism. Probably we should revisit the layout of this status bar in the future.

Reviewed By: jknoxville

Differential Revision: D19251588

fbshipit-source-id: 1dfd07be383d4ba318f344ebff4b08ed36194c58

docs/extending/js-plugin-api.md

@@ -80,7 +80,13 @@ static persistedStateReducer<PersistedState>(
 The job of the `persistedStateReducer` is to merge incoming data into the state, so that next time the plugin is activated, the persisted state will be ready.
 If a plugin has a `persistedStateReducer`, and the plugin is not open in flipper, incoming messages are queued until the plugin is opened.
 
-The amount of events that is cached for a plugin is controlled by the optional static field `maxQueueSize`, which by default is set to `10000` events.
+The number of events that are cached for a plugin is controlled by the optional static field `maxQueueSize`, which defaults to `10000` events.
+
+<div class="warning">
+
+Note that if a plugin is not starred by the user, it will not receive any messages when it is not selected by the user. Even when it has a `persistedStateReducer`. This prevents plugins that are not actively used by the user from wasting a lot of CPU / memory.
+
+</div>
 
 The data that is produced from `persistedStateReducer` should be immutable, but also structurally sharing unchanged parts of the state with the previous state to avoid performance hiccups. To simplify this process we recommend using the [Immer](https://immerjs.github.io/immer/docs/introduction) package.
 Immer makes it possible to keep the reducer concise by directly supporting "writing" to the current state, and keeping track of that in the background.

src/PluginContainer.tsx

@@ -33,7 +33,7 @@ import React, {PureComponent} from 'react';
 import {connect, ReactReduxContext} from 'react-redux';
 import {setPluginState} from './reducers/pluginStates';
 import {selectPlugin} from './reducers/connections';
-import {State as Store} from './reducers/index';
+import {State as Store, MiddlewareAPI} from './reducers/index';
 import {activateMenuItems} from './MenuBar';
 import {Message} from './reducers/pluginMessageQueue';
 import {Idler} from './utils/Idler';
@@ -146,6 +146,10 @@ class PluginContainer extends PureComponent<Props, State> {
 
   state = {progress: {current: 0, total: 0}};
 
+  get store(): MiddlewareAPI {
+    return this.context.store;
+  }
+
   componentWillUnmount() {
     if (this.plugin) {
       this.plugin._teardown();
@@ -179,7 +183,7 @@ class PluginContainer extends PureComponent<Props, State> {
         processMessageQueue(
           activePlugin,
           pluginKey,
-          this.context.store,
+          this.store,
           progress => {
             this.setState({progress});
           },

src/chrome/StatusBar.tsx

@@ -8,11 +8,12 @@
  */
 
 import {colors} from '../ui/components/colors';
-import {styled} from '../ui';
+import {styled, Glyph} from '../ui';
 import {connect} from 'react-redux';
 import {State} from '../reducers';
 import React, {ReactElement} from 'react';
 import Text from '../ui/components/Text';
+import {pluginIsStarred} from '../reducers/connections';
 
 const StatusBarContainer = styled(Text)({
   backgroundColor: colors.macOSTitleBarBackgroundBlur,
@@ -21,17 +22,18 @@ const StatusBarContainer = styled(Text)({
   padding: '0 10px',
   textOverflow: 'ellipsis',
   overflow: 'hidden',
+  textAlign: 'center',
 });
 
 type Props = {
-  statusMessage: string | null;
+  statusMessage: React.ReactNode | string | null;
 };
 
 export function statusBarView(props: Props): ReactElement | null {
   const {statusMessage} = props;
   if (statusMessage) {
     return (
-      <StatusBarContainer italic={true} whiteSpace="nowrap">
+      <StatusBarContainer whiteSpace="nowrap">
         {statusMessage}
       </StatusBarContainer>
     );
@@ -40,13 +42,45 @@ export function statusBarView(props: Props): ReactElement | null {
   }
 }
 
-export default connect<Props, void, {}, State>(
+export default connect<Props, void, {}, State>((state: State) => {
-  ({application: {statusMessages}}) => {
+  const {
+    application: {statusMessages},
+  } = state;
   if (statusMessages.length > 0) {
     return {statusMessage: statusMessages[statusMessages.length - 1]};
+  } else if (isPreviewingBackgroundPlugin(state)) {
+    return {
+      statusMessage: (
+        <>
+          <Glyph
+            name="caution-triangle"
+            color={colors.light20}
+            size={12}
+            variant="filled"
+            style={{marginRight: 8}}
+          />
+          The current plugin would like to send messages while it is in the
+          background. However, since this plugin is not starred, these messages
+          will be dropped. Star this plugin to unlock its full capabilities.
+        </>
+      ),
+    };
   }
   return {
     statusMessage: null,
   };
-  },
+})(statusBarView);
-)(statusBarView);
+
+function isPreviewingBackgroundPlugin(state: State): boolean {
+  const {
+    connections: {selectedApp, selectedPlugin},
+  } = state;
+  if (!selectedPlugin || !selectedApp) {
+    return false;
+  }
+  const activePlugin = state.plugins.clientPlugins.get(selectedPlugin);
+  if (!activePlugin || !activePlugin.persistedStateReducer) {
+    return false;
+  }
+  return !pluginIsStarred(state.connections, selectedPlugin);
+}

src/reducers/connections.tsx

@@ -7,6 +7,8 @@
  * @format
  */
 
+import {produce} from 'immer';
+
 import BaseDevice from '../devices/BaseDevice';
 import MacDevice from '../devices/MacDevice';
 import Client from '../Client';
@@ -23,7 +25,8 @@ import NotificationScreen from '../chrome/NotificationScreen';
 import SupportRequestForm from '../fb-stubs/SupportRequestFormManager';
 import SupportRequestFormV2 from '../fb-stubs/SupportRequestFormV2';
 import SupportRequestDetails from '../fb-stubs/SupportRequestDetails';
-import {produce} from 'immer';
+import {getPluginKey} from '../utils/pluginUtils';
+import {deconstructClientId} from '../utils/clientUtils';
 
 export type StaticView =
   | null
@@ -581,3 +584,23 @@ function updateSelection(state: Readonly<State>): State {
 
   return {...state, ...updates};
 }
+
+export function getSelectedPluginKey(state: State): string | undefined {
+  return state.selectedPlugin
+    ? getPluginKey(
+        state.selectedApp,
+        state.selectedDevice,
+        state.selectedPlugin,
+      )
+    : undefined;
+}
+
+export function pluginIsStarred(state: State, pluginId: string): boolean {
+  const {selectedApp} = state;
+  if (!selectedApp) {
+    return false;
+  }
+  const appInfo = deconstructClientId(selectedApp);
+  const starred = state.userStarredPlugins[appInfo.app];
+  return starred && starred.indexOf(pluginId) > -1;
+}

src/utils/messageQueue.tsx

@@ -17,8 +17,7 @@ import {
   Message,
 } from '../reducers/pluginMessageQueue';
 import {Idler, BaseIdler} from './Idler';
-import {getPluginKey} from './pluginUtils';
+import {pluginIsStarred, getSelectedPluginKey} from '../reducers/connections';
-import {deconstructClientId} from './clientUtils';
 
 const MAX_BACKGROUND_TASK_TIME = 25;
 
@@ -138,14 +137,15 @@ export function processMessageLater(
   },
   message: {method: string; params?: any},
 ) {
-  const isSelected = pluginKey === getSelectedPluginKey(store.getState());
+  const isSelected =
+    pluginKey === getSelectedPluginKey(store.getState().connections);
   switch (true) {
     case isSelected && getPendingMessages(store, pluginKey).length === 0:
       processMessageImmediately(store, pluginKey, plugin, message);
       break;
     case isSelected:
     case plugin instanceof FlipperDevicePlugin:
-    case pluginIsStarred(store.getState(), plugin.id):
+    case pluginIsStarred(store.getState().connections, plugin.id):
       store.dispatch(
         queueMessage(
           pluginKey,
@@ -158,26 +158,6 @@ export function processMessageLater(
   }
 }
 
-function getSelectedPluginKey(state: State): string | undefined {
-  return state.connections.selectedPlugin
-    ? getPluginKey(
-        state.connections.selectedApp,
-        state.connections.selectedDevice,
-        state.connections.selectedPlugin,
-      )
-    : undefined;
-}
-
-function pluginIsStarred(state: State, pluginId: string): boolean {
-  const {selectedApp} = state.connections;
-  if (!selectedApp) {
-    return false;
-  }
-  const appInfo = deconstructClientId(selectedApp);
-  const starred = state.connections.userStarredPlugins[appInfo.app];
-  return starred && starred.indexOf(pluginId) > -1;
-}
-
 export async function processMessageQueue(
   plugin: {
     defaultPersistedState: any;