NetNewsWire/Frameworks/Account/Feedly/Refresh/FeedlySyncStrategy.swift

164 lines
6.2 KiB
Swift

//
// FeedlySyncStrategy.swift
// Account
//
// Created by Kiel Gillard on 19/9/19.
// Copyright © 2019 Ranchero Software, LLC. All rights reserved.
//
import Foundation
import os.log
final class FeedlySyncStrategy {
let account: Account
let caller: FeedlyAPICaller
let operationQueue: OperationQueue
let articleStatusCoordinator: FeedlyArticleStatusCoordinator
let log: OSLog
init(account: Account, caller: FeedlyAPICaller, articleStatusCoordinator: FeedlyArticleStatusCoordinator, log: OSLog) {
self.account = account
self.caller = caller
self.operationQueue = OperationQueue()
self.log = log
self.articleStatusCoordinator = articleStatusCoordinator
}
func cancel() {
os_log(.debug, log: log, "Cancelling all operations.")
self.operationQueue.cancelAllOperations()
}
private var startSyncCompletionHandler: ((Result<Void, Error>) -> ())?
/// The truth is in the cloud.
func startSync(completionHandler: @escaping (Result<Void, Error>) -> ()) {
guard operationQueue.operationCount == 0 else {
os_log(.debug, log: log, "Reqeusted start sync but ignored because a sync is already in progress.")
completionHandler(.success(()))
return
}
// Since the truth is in the cloud, everything hinges of what Collections the user has.
let getCollections = FeedlyGetCollectionsOperation(caller: caller, log: log)
getCollections.delegate = self
// Ensure a folder exists for each Collection, removing Folders without a corresponding Collection.
let mirrorCollectionsAsFolders = FeedlyMirrorCollectionsAsFoldersOperation(account: account,
collectionsProvider: getCollections,
caller: caller,
log: log)
mirrorCollectionsAsFolders.delegate = self
mirrorCollectionsAsFolders.addDependency(getCollections)
// Ensure feeds are created and grouped by their folders.
let createFeedsOperation = FeedlyCreateFeedsForCollectionFoldersOperation(account: account,
collectionsAndFoldersProvider: mirrorCollectionsAsFolders,
log: log)
createFeedsOperation.delegate = self
createFeedsOperation.addDependency(mirrorCollectionsAsFolders)
// Get the streams for each Collection. It will call back to enqueue more operations.
let getCollectionStreams = FeedlyRequestStreamsOperation(account: account,
collectionsProvider: getCollections,
caller: caller,
log: log)
getCollectionStreams.delegate = self
getCollectionStreams.queueDelegate = self
getCollectionStreams.addDependency(getCollections)
// Last operation to perform, which should be dependent on any other operation added to the queue.
let syncId = UUID().uuidString
let completionOperation = BlockOperation { [weak self] in
if let self = self {
os_log(.debug, log: self.log, "Sync completed: %@", syncId)
self.startSyncCompletionHandler = nil
}
completionHandler(.success(()))
}
completionOperation.addDependency(getCollections)
completionOperation.addDependency(mirrorCollectionsAsFolders)
completionOperation.addDependency(createFeedsOperation)
completionOperation.addDependency(getCollectionStreams)
finalOperation = completionOperation
startSyncCompletionHandler = completionHandler
let minimumOperations = [getCollections,
mirrorCollectionsAsFolders,
createFeedsOperation,
getCollectionStreams,
completionOperation]
operationQueue.addOperations(minimumOperations, waitUntilFinished: false)
os_log(.debug, log: log, "Sync started: %@", syncId)
}
private weak var finalOperation: Operation?
}
extension FeedlySyncStrategy: FeedlyRequestStreamsOperationDelegate {
func feedlyRequestStreamsOperation(_ operation: FeedlyRequestStreamsOperation, enqueue collectionStreamOperation: FeedlyGetCollectionStreamOperation) {
collectionStreamOperation.delegate = self
os_log(.debug, log: log, "Requesting stream for collection \"%@\"", collectionStreamOperation.collection.label)
// Parse the contents of this collection's stream.
let parseItemsOperation = FeedlyGetStreamParsedItemsOperation(account: account,
collectionStreamProvider: collectionStreamOperation,
caller: caller,
log: log)
parseItemsOperation.delegate = self
parseItemsOperation.addDependency(collectionStreamOperation)
// Group the stream's content by feed.
let groupItemsByFeed = FeedlyOrganiseParsedItemsByFeedOperation(account: account,
parsedItemsProvider: parseItemsOperation,
log: log)
groupItemsByFeed.delegate = self
groupItemsByFeed.addDependency(parseItemsOperation)
// Update the account with the articles for the feeds in the stream.
let updateOperation = FeedlyUpdateAccountFeedsWithItemsOperation(account: account,
organisedItemsProvider: groupItemsByFeed,
log: log)
updateOperation.delegate = self
updateOperation.addDependency(groupItemsByFeed)
// Once the articles are in the account, ensure they have the correct status
let ensureUnreadOperation = FeedlyRefreshStreamEntriesStatusOperation(account: account,
collectionStreamProvider: collectionStreamOperation,
articleStatusCoordinator: articleStatusCoordinator,
log: log)
ensureUnreadOperation.delegate = self
ensureUnreadOperation.addDependency(updateOperation)
// Sync completes successfully when the account has been updated with all the parsedd entries from the stream.
if let operation = finalOperation {
operation.addDependency(ensureUnreadOperation)
}
let operations = [collectionStreamOperation, parseItemsOperation, groupItemsByFeed, updateOperation, ensureUnreadOperation]
operationQueue.addOperations(operations, waitUntilFinished: false)
}
}
extension FeedlySyncStrategy: FeedlyOperationDelegate {
func feedlyOperation(_ operation: FeedlyOperation, didFailWith error: Error) {
os_log(.debug, log: log, "%@ failed so sync failed with error %@", operation, error.localizedDescription)
cancel()
startSyncCompletionHandler?(.failure(error))
startSyncCompletionHandler = nil
}
}