lastn: simplify computing the effective last N value

react/features/base/lastn/actionTypes.js

@@ -1,11 +0,0 @@
-// @flow
-
-/**
- * The type of (redux) action which sets the video channel's lastN (value).
- *
- * {
- *     type: SET_LASTN,
- *     lastN: number
- * }
- */
-export const SET_LASTN = 'SET_LASTN';

react/features/base/lastn/actions.js

@@ -1,34 +0,0 @@
-// @flow
-
-import { SET_LASTN } from './actionTypes';
-
-import type { Dispatch } from 'redux';
-
-/**
- * Sets the video channel's last N (value) of the current conference. A value of
- * undefined shall be used to reset it to the default value.
- *
- * @param {(number|undefined)} lastN - The last N value to be set.
- * @returns {Function}
- */
-export function setLastN(lastN: ?number) {
-    return (dispatch: Dispatch<any>, getState: Function) => {
-        if (typeof lastN === 'undefined') {
-            const config = getState()['features/base/config'];
-
-            /* eslint-disable no-param-reassign */
-
-            lastN = config.channelLastN;
-            if (typeof lastN === 'undefined') {
-                lastN = -1;
-            }
-
-            /* eslint-enable no-param-reassign */
-        }
-
-        dispatch({
-            type: SET_LASTN,
-            lastN
-        });
-    };
-}

react/features/base/lastn/index.js

@@ -1,6 +1,3 @@
 // @flow
 
-export * from './actions';
-export * from './actionTypes';
-
 import './middleware';

react/features/base/lastn/middleware.js

@@ -9,152 +9,60 @@ import { SET_AUDIO_ONLY } from '../audio-only';
 import { CONFERENCE_JOINED } from '../conference/actionTypes';
 import { MiddlewareRegistry } from '../redux';
 
-import { setLastN } from './actions';
-import { SET_LASTN } from './actionTypes';
-
 declare var APP: Object;
-
 const logger = getLogger('features/base/lastn');
 
 
 MiddlewareRegistry.register(store => next => action => {
+    const result = next(action);
+
     switch (action.type) {
     case APP_STATE_CHANGED:
-        return _appStateChanged(store, next, action);
-
     case CONFERENCE_JOINED:
-        return _conferenceJoined(store, next, action);
-
     case SET_AUDIO_ONLY:
-        return _setAudioOnly(store, next, action);
-
     case SET_FILMSTRIP_ENABLED:
-        return _setFilmstripEnabled(store, next, action);
-
-    case SET_LASTN:
-        return _setLastN(store, next, action);
+        _updateLastN(store);
+        break;
     }
 
-    return next(action);
+    return result;
 });
 
 /**
- * Adjusts the lasN value based on the app state.
+ * Updates the last N value in the conference based on the current state of the redux store.
  *
- * @param {Store} store - The redux store in which the specified {@code action}
- * is being dispatched.
- * @param {Dispatch} next - The redux {@code dispatch} function to dispatch the
- * specified {@code action} to the specified {@code store}.
- * @param {Action} action - The redux action {@code APP_STATE_CHANGED} which is
- * being dispatched in the specified {@code store}.
+ * @param {Store} store - The redux store.
  * @private
- * @returns {Object} The value returned by {@code next(action)}.
+ * @returns {void}
  */
-function _appStateChanged({ dispatch, getState }, next, action) {
-    const { enabled: audioOnly } = getState()['features/base/audio-only'];
-
-    if (!audioOnly) {
-        const { appState } = action;
-        const lastN = appState === 'active' ? undefined : 0;
-
-        dispatch(setLastN(lastN));
-        logger.log(`App state changed - updated lastN to ${String(lastN)}`);
+function _updateLastN({ getState }) {
+    const state = getState();
+    const { conference } = state['features/base/conference'];
+    const { enabled: audioOnly } = state['features/base/audio-only'];
+    const { appState } = state['features/background'];
+    const { enabled: filmStripEnabled } = state['features/filmstrip'];
+    const config = state['features/base/config'];
+
+    if (!conference) {
+        logger.debug('There is no active conference, not updating last N');
+
+        return;
     }
 
-    return next(action);
-}
-
-/**
- * Adjusts the lasN value upon joining a conference.
- *
- * @param {Store} store - The redux store in which the specified {@code action}
- * is being dispatched.
- * @param {Dispatch} next - The redux {@code dispatch} function to dispatch the
- * specified {@code action} to the specified {@code store}.
- * @param {Action} action - The redux action {@code CONFERENCE_JOINED} which is
- * being dispatched in the specified {@code store}.
- * @private
- * @returns {Object} The value returned by {@code next(action)}.
- */
-function _conferenceJoined({ dispatch, getState }, next, action) {
-    const { conference } = action;
-    const { enabled: audioOnly } = getState()['features/base/audio-only'];
-
-    audioOnly && conference.getLastN() !== 0 && dispatch(setLastN(0));
-
-    return next(action);
-}
-
-/**
- * Sets the audio-only flag for the current conference. When audio-only is set,
- * local video is muted and last N is set to 0 to avoid receiving remote video.
- *
- * @param {Store} store - The redux store in which the specified {@code action}
- * is being dispatched.
- * @param {Dispatch} next - The redux {@code dispatch} function to dispatch the
- * specified {@code action} to the specified {@code store}.
- * @param {Action} action - The redux action {@code SET_AUDIO_ONLY} which is
- * being dispatched in the specified {@code store}.
- * @private
- * @returns {Object} The value returned by {@code next(action)}.
- */
-function _setAudioOnly({ dispatch }, next, action) {
-    const { audioOnly } = action;
-
-    // Set lastN to 0 in case audio-only is desired; leave it as undefined,
-    // otherwise, and the default lastN value will be chosen automatically.
-    dispatch(setLastN(audioOnly ? 0 : undefined));
+    const defaultLastN = typeof config.channelLastN === 'undefined' ? -1 : config.channelLastN;
+    let lastN = defaultLastN;
 
-    return next(action);
-}
-
-/**
- * Notifies the feature filmstrip that the action {@link SET_FILMSTRIP_ENABLED}
- * is being dispatched within a specific redux store.
- *
- * @param {Store} store - The redux store in which the specified action is being
- * dispatched.
- * @param {Dispatch} next - The redux dispatch function to dispatch the
- * specified action to the specified store.
- * @param {Action} action - The redux action {@code SET_FILMSTRIP_ENABLED} which
- * is being dispatched in the specified store.
- * @private
- * @returns {Object} The value returned by {@code next(action)}.
- */
-function _setFilmstripEnabled({ dispatch, getState }, next, action) {
-    // FIXME This action is not currently dispatched on web.
-    if (typeof APP === 'undefined') {
-        const { enabled } = action;
-        const { enabled: audioOnly } = getState()['features/base/audio-only'];
-
-        audioOnly || dispatch(setLastN(enabled ? undefined : 1));
+    if (audioOnly || appState !== 'active') {
+        lastN = 0;
+    } else if (!filmStripEnabled) {
+        lastN = 1;
     }
 
-    return next(action);
-}
+    logger.info(`Setting last N to: ${lastN}`);
 
-/**
- * Sets the last N (value) of the video channel in the conference.
- *
- * @param {Store} store - The redux store in which the specified {@code action}
- * is being dispatched.
- * @param {Dispatch} next - The redux {@code dispatch} function to dispatch the
- * specified {@code action} to the specified {@code store}.
- * @param {Action} action - The redux action {@code SET_LASTN} which is being
- * dispatched in the specified {@code store}.
- * @private
- * @returns {Object} The value returned by {@code next(action)}.
- */
-function _setLastN({ getState }, next, action) {
-    const { conference } = getState()['features/base/conference'];
-
-    if (conference) {
-        try {
-            conference.setLastN(action.lastN);
-        } catch (err) {
-            logger.error(`Failed to set lastN: ${err}`);
-        }
+    try {
+        conference.setLastN(lastN);
+    } catch (err) {
+        logger.error(`Failed to set lastN: ${err}`);
     }
-
-    return next(action);
 }