[RN] Move all mobile only features to a subdirectory

react/features/mobile/background/middleware.js

@@ -0,0 +1,124 @@
+/* @flow */
+
+import { AppState } from 'react-native';
+import type { Dispatch } from 'redux';
+
+import {
+    APP_WILL_MOUNT,
+    APP_WILL_UNMOUNT
+} from '../../app';
+import { MiddlewareRegistry } from '../../base/redux';
+
+import {
+    _setAppStateListener,
+    _setBackgroundVideoMuted,
+    appStateChanged
+} from './actions';
+import {
+    _SET_APP_STATE_LISTENER,
+    _SET_LASTN,
+    APP_STATE_CHANGED
+} from './actionTypes';
+
+/**
+ * Middleware that captures App lifetime actions and subscribes to application
+ * state changes. When the application state changes it will fire the action
+ * required to mute or unmute the local video in case the application goes to
+ * the background or comes back from it.
+ *
+ * @param {Store} store - Redux store.
+ * @returns {Function}
+ * @see {@link https://facebook.github.io/react-native/docs/appstate.html}
+ */
+MiddlewareRegistry.register(store => next => action => {
+    switch (action.type) {
+    case _SET_APP_STATE_LISTENER: {
+        // Remove the current/old AppState listener.
+        const { appStateListener } = store.getState()['features/background'];
+
+        if (appStateListener) {
+            AppState.removeEventListener('change', appStateListener);
+        }
+
+        // Add the new AppState listener.
+        if (action.listener) {
+            AppState.addEventListener('change', action.listener);
+        }
+        break;
+    }
+
+    case _SET_LASTN: {
+        const { conference } = store.getState()['features/base/conference'];
+
+        if (conference) {
+            try {
+                conference.setLastN(action.lastN);
+            } catch (err) {
+                console.warn(`Failed to set lastN: ${err}`);
+            }
+        }
+
+        break;
+    }
+
+    case APP_STATE_CHANGED:
+        _appStateChanged(store.dispatch, action.appState);
+        break;
+
+    case APP_WILL_MOUNT:
+        store.dispatch(
+                _setAppStateListener(
+                        _onAppStateChange.bind(undefined, store.dispatch)));
+        break;
+
+    case APP_WILL_UNMOUNT:
+        store.dispatch(_setAppStateListener(null));
+        break;
+    }
+
+    return next(action);
+});
+
+/**
+ * Handles app state changes. Dispatches the necessary Redux actions for the
+ * local video to be muted when the app goes to the background, and to be
+ * unmuted when the app comes back.
+ *
+ * @param {Dispatch} dispatch - Redux dispatch function.
+ * @param {string} appState - The current app state.
+ * @private
+ * @returns {void}
+ */
+function _appStateChanged(dispatch: Dispatch<*>, appState: string) {
+    let muted;
+
+    switch (appState) {
+    case 'active':
+        muted = false;
+        break;
+
+    case 'background':
+        muted = true;
+        break;
+
+    case 'inactive':
+    default:
+        // XXX: We purposely don't handle the 'inactive' app state.
+        return;
+    }
+
+    dispatch(_setBackgroundVideoMuted(muted));
+}
+
+/**
+ * Called by React Native's AppState API to notify that the application state
+ * has changed. Dispatches the change within the (associated) Redux store.
+ *
+ * @param {Dispatch} dispatch - Redux dispatch function.
+ * @param {string} appState - The current application execution state.
+ * @private
+ * @returns {void}
+ */
+function _onAppStateChange(dispatch: Dispatch<*>, appState: string) {
+    dispatch(appStateChanged(appState));
+}