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Diffstat (limited to 'browser/components/newtab/content-src/lib/init-store.js')
| -rw-r--r-- | browser/components/newtab/content-src/lib/init-store.js | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/browser/components/newtab/content-src/lib/init-store.js b/browser/components/newtab/content-src/lib/init-store.js new file mode 100644 index 0000000000..77ae5363bf --- /dev/null +++ b/browser/components/newtab/content-src/lib/init-store.js @@ -0,0 +1,175 @@ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this file, + * You can obtain one at http://mozilla.org/MPL/2.0/. */ + +/* eslint-env mozilla/remote-page */ + +import { + actionCreators as ac, + actionTypes as at, + actionUtils as au, +} from "common/Actions.sys.mjs"; +import { applyMiddleware, combineReducers, createStore } from "redux"; + +export const MERGE_STORE_ACTION = "NEW_TAB_INITIAL_STATE"; +export const OUTGOING_MESSAGE_NAME = "ActivityStream:ContentToMain"; +export const INCOMING_MESSAGE_NAME = "ActivityStream:MainToContent"; +export const EARLY_QUEUED_ACTIONS = [at.SAVE_SESSION_PERF_DATA]; + +/** + * A higher-order function which returns a reducer that, on MERGE_STORE action, + * will return the action.data object merged into the previous state. + * + * For all other actions, it merely calls mainReducer. + * + * Because we want this to merge the entire state object, it's written as a + * higher order function which takes the main reducer (itself often a call to + * combineReducers) as a parameter. + * + * @param {function} mainReducer reducer to call if action != MERGE_STORE_ACTION + * @return {function} a reducer that, on MERGE_STORE_ACTION action, + * will return the action.data object merged + * into the previous state, and the result + * of calling mainReducer otherwise. + */ +function mergeStateReducer(mainReducer) { + return (prevState, action) => { + if (action.type === MERGE_STORE_ACTION) { + return { ...prevState, ...action.data }; + } + + return mainReducer(prevState, action); + }; +} + +/** + * messageMiddleware - Middleware that looks for SentToMain type actions, and sends them if necessary + */ +const messageMiddleware = store => next => action => { + const skipLocal = action.meta && action.meta.skipLocal; + if (au.isSendToMain(action)) { + RPMSendAsyncMessage(OUTGOING_MESSAGE_NAME, action); + } + if (!skipLocal) { + next(action); + } +}; + +export const rehydrationMiddleware = ({ getState }) => { + // NB: The parameter here is MiddlewareAPI which looks like a Store and shares + // the same getState, so attached properties are accessible from the store. + getState.didRehydrate = false; + getState.didRequestInitialState = false; + return next => action => { + if (getState.didRehydrate || window.__FROM_STARTUP_CACHE__) { + // Startup messages can be safely ignored by the about:home document + // stored in the startup cache. + if ( + window.__FROM_STARTUP_CACHE__ && + action.meta && + action.meta.isStartup + ) { + return null; + } + return next(action); + } + + const isMergeStoreAction = action.type === MERGE_STORE_ACTION; + const isRehydrationRequest = action.type === at.NEW_TAB_STATE_REQUEST; + + if (isRehydrationRequest) { + getState.didRequestInitialState = true; + return next(action); + } + + if (isMergeStoreAction) { + getState.didRehydrate = true; + return next(action); + } + + // If init happened after our request was made, we need to re-request + if (getState.didRequestInitialState && action.type === at.INIT) { + return next(ac.AlsoToMain({ type: at.NEW_TAB_STATE_REQUEST })); + } + + if ( + au.isBroadcastToContent(action) || + au.isSendToOneContent(action) || + au.isSendToPreloaded(action) + ) { + // Note that actions received before didRehydrate will not be dispatched + // because this could negatively affect preloading and the the state + // will be replaced by rehydration anyway. + return null; + } + + return next(action); + }; +}; + +/** + * This middleware queues up all the EARLY_QUEUED_ACTIONS until it receives + * the first action from main. This is useful for those actions for main which + * require higher reliability, i.e. the action will not be lost in the case + * that it gets sent before the main is ready to receive it. Conversely, any + * actions allowed early are accepted to be ignorable or re-sendable. + */ +export const queueEarlyMessageMiddleware = ({ getState }) => { + // NB: The parameter here is MiddlewareAPI which looks like a Store and shares + // the same getState, so attached properties are accessible from the store. + getState.earlyActionQueue = []; + getState.receivedFromMain = false; + return next => action => { + if (getState.receivedFromMain) { + next(action); + } else if (au.isFromMain(action)) { + next(action); + getState.receivedFromMain = true; + // Sending out all the early actions as main is ready now + getState.earlyActionQueue.forEach(next); + getState.earlyActionQueue.length = 0; + } else if (EARLY_QUEUED_ACTIONS.includes(action.type)) { + getState.earlyActionQueue.push(action); + } else { + // Let any other type of action go through + next(action); + } + }; +}; + +/** + * initStore - Create a store and listen for incoming actions + * + * @param {object} reducers An object containing Redux reducers + * @param {object} intialState (optional) The initial state of the store, if desired + * @return {object} A redux store + */ +export function initStore(reducers, initialState) { + const store = createStore( + mergeStateReducer(combineReducers(reducers)), + initialState, + global.RPMAddMessageListener && + applyMiddleware( + queueEarlyMessageMiddleware, + rehydrationMiddleware, + messageMiddleware + ) + ); + + if (global.RPMAddMessageListener) { + global.RPMAddMessageListener(INCOMING_MESSAGE_NAME, msg => { + try { + store.dispatch(msg.data); + } catch (ex) { + console.error("Content msg:", msg, "Dispatch error: ", ex); + dump( + `Content msg: ${JSON.stringify(msg)}\nDispatch error: ${ex}\n${ + ex.stack + }` + ); + } + }); + } + + return store; +} |