NetNewsWire/Frameworks/Database/ArticlesTable.swift

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//
// ArticlesTable.swift
// Evergreen
//
// Created by Brent Simmons on 5/9/16.
// Copyright © 2016 Ranchero Software, LLC. All rights reserved.
//
import Foundation
import RSCore
import RSDatabase
import RSParser
import Data
final class ArticlesTable: DatabaseTable {
let name: String
private let accountID: String
private let queue: RSDatabaseQueue
private let statusesTable: StatusesTable
private let authorsLookupTable: DatabaseLookupTable
private let attachmentsLookupTable: DatabaseLookupTable
private let tagsLookupTable: DatabaseLookupTable
// TODO: update articleCutoffDate as time passes and based on user preferences.
private var articleCutoffDate = NSDate.rs_dateWithNumberOfDays(inThePast: 3 * 31)!
private var maximumArticleCutoffDate = NSDate.rs_dateWithNumberOfDays(inThePast: 4 * 31)!
init(name: String, accountID: String, queue: RSDatabaseQueue) {
self.name = name
self.accountID = accountID
self.queue = queue
let statusesTable = StatusesTable(queue: queue)
let authorsTable = AuthorsTable(name: DatabaseTableName.authors)
self.authorsLookupTable = DatabaseLookupTable(name: DatabaseTableName.authorsLookup, objectIDKey: DatabaseKey.articleID, relatedObjectIDKey: DatabaseKey.authorID, relatedTable: authorsTable, relationshipName: RelationshipName.authors)
let tagsTable = TagsTable(name: DatabaseTableName.tags)
self.tagsLookupTable = DatabaseLookupTable(name: DatabaseTableName.tags, objectIDKey: DatabaseKey.articleID, relatedObjectIDKey: DatabaseKey.tagName, relatedTable: tagsTable, relationshipName: RelationshipName.tags)
let attachmentsTable = AttachmentsTable(name: DatabaseTableName.attachments)
self.attachmentsLookupTable = DatabaseLookupTable(name: DatabaseTableName.attachmentsLookup, objectIDKey: DatabaseKey.articleID, relatedObjectIDKey: DatabaseKey.attachmentID, relatedTable: attachmentsTable, relationshipName: RelationshipName.attachments)
}
// MARK: Fetching
func fetchArticles(_ feed: Feed) -> Set<Article> {
let feedID = feed.feedID
var articles = Set<Article>()
queue.fetchSync { (database) in
articles = self.fetchArticlesForFeedID(feedID, withLimits: true, database: database)
}
return articles
}
func fetchArticlesAsync(_ feed: Feed, withLimits: Bool, _ resultBlock: @escaping ArticleResultBlock) {
let feedID = feed.feedID
queue.fetch { (database) in
let articles = self.fetchArticlesForFeedID(feedID, withLimits: withLimits, database: database)
DispatchQueue.main.async {
resultBlock(articles)
}
}
}
func fetchUnreadArticles(for feeds: Set<Feed>) -> Set<Article> {
return fetchUnreadArticles(feeds.feedIDs())
}
// MARK: Updating
func update(_ feed: Feed, _ parsedFeed: ParsedFeed, _ completion: @escaping UpdateArticlesWithFeedCompletionBlock) {
if parsedFeed.items.isEmpty {
completion(nil, nil)
return
}
// 1. Ensure statuses for all the parsedItems.
// 2. Ignore parsedItems that are userDeleted || (!starred and really old)
// 3. Fetch all articles for the feed.
// 4. Create Articles with parsedItems.
// 5. Create array of Articles not in database and save them.
// 6. Create array of updated Articles and save whats changed.
// 7. Call back with new and updated Articles.
let feedID = feed.feedID
let parsedItemArticleIDs = Set(parsedFeed.items.map { $0.databaseIdentifierWithFeed(feed) })
let parsedItemsDictionary = parsedFeed.itemsDictionary(with: feed)
statusesTable.ensureStatusesForArticleIDs(parsedItemArticleIDs) { // 1
let filteredParsedItems = self.filterParsedItems(parsedItemsDictionary) // 2
if filteredParsedItems.isEmpty {
completion(nil, nil)
return
}
queue.update{ (database) in
let fetchedArticles = self.fetchArticlesForFeedID(feedID, withLimits: false, database: database) //3
let fetchedArticlesDictionary = fetchedArticles.dictionary()
let incomingArticles = Article.articlesWithParsedItems(filteredParsedItems, accountID, feedID) //4
let incomingArticlesDictionary = incomingArticles.dictionary()
let newArticles = Set(incomingArticles.filter { fetchedArticles[$0.articleID] == nil }) //5
if !newArticles.isEmpty {
saveNewArticles(newArticles, database)
}
let updatedArticles = incomingArticles.filter{ (incomingArticle) -> Bool in //6
if let existingArticle = fetchedArticles[incomingArticle.articleID] {
if existingArticle != incomingArticle {
return true
}
}
return false
}
if !updatedArticles.isEmpty {
saveUpdatedArticles(Set(updatedArticles), fetchedArticlesDictionary, database)
}
DispatchQueue.main.async {
completion(newArticles, updatedArticles) //7
}
}
}
}
// MARK: Unread Counts
func fetchUnreadCounts(_ feeds: Set<Feed>, _ completion: @escaping UnreadCountCompletionBlock) {
let feedIDs = feeds.feedIDs()
var unreadCountTable = UnreadCountTable()
queue.fetch { (database) in
for feedID in feedIDs {
unreadCountTable[feedID] = self.fetchUnreadCount(feedID, database)
}
DispatchQueue.main.async() {
completion(unreadCountTable)
}
}
}
// MARK: Status
func mark(_ articles: Set<Article>, _ statusKey: String, _ flag: Bool) {
// Sets flag in both memory and in database.
let articleIDs = articles.flatMap { (article) -> String? in
guard let status = article.status else {
assertionFailure("Each article must have a status.")
return nil
}
if status.boolStatus(forKey: statusKey) == flag {
return nil
}
status.setBoolStatus(flag, forKey: statusKey)
return article.articleID
}
if articleIDs.isEmpty {
return
}
queue.update { (database) in
self.statusesTable.markArticleIDs(Set(articleIDs), statusKey, flag, database)
}
}
}
// MARK: - Private
private extension ArticlesTable {
// MARK: Fetching
// func attachRelatedObjects(_ articles: Set<Article>, _ database: FMDatabase) {
//
// let articleArray = articles.map { $0 as DatabaseObject }
//
// authorsLookupTable.attachRelatedObjects(to: articleArray, in: database)
// attachmentsLookupTable.attachRelatedObjects(to: articleArray, in: database)
// tagsLookupTable.attachRelatedObjects(to: articleArray, in: database)
//
// // In theory, its impossible to have a fetched article without a status.
// // Lets handle that impossibility anyway.
// // Remember that, if nothing else, the user can edit the SQLite database,
// // and thus could delete all their statuses.
//
// statusesTable.ensureStatusesForArticles(articles, database)
// }
func articleWithRow(_ row: FMResultSet) -> Article? {
guard let account = account else {
return nil
}
guard let article = Article(row: row, account: account) else {
return nil
}
// Note: the row is a result of a JOIN query with the statuses table,
// so we can get the status at the same time and avoid additional database lookups.
article.status = statusesTable.statusWithRow(row)
return article
}
func articlesWithResultSet(_ resultSet: FMResultSet, _ database: FMDatabase) -> Set<Article> {
let articles = resultSet.mapToSet(articleWithRow)
attachRelatedObjects(articles, database)
return articles
}
func fetchArticlesWithWhereClause(_ database: FMDatabase, whereClause: String, parameters: [AnyObject], withLimits: Bool) -> Set<Article> {
// Dont fetch articles that shouldnt appear in the UI. The rules:
// * Must not be deleted.
// * Must be either 1) starred or 2) dateArrived must be newer than cutoff date.
let sql = withLimits ? "select * from articles natural join statuses where \(whereClause) and userDeleted=0 and (starred=1 or dateArrived>?);" : "select * from articles natural join statuses where \(whereClause);"
return articlesWithSQL(sql, parameters + [articleCutoffDate as AnyObject], database)
}
func fetchUnreadCount(_ feedID: String, _ database: FMDatabase) -> Int {
// Count only the articles that would appear in the UI.
// * Must be unread.
// * Must not be deleted.
// * Must be either 1) starred or 2) dateArrived must be newer than cutoff date.
let sql = "select count(*) from articles natural join statuses where feedID=? and read=0 and userDeleted=0 and (starred=1 or dateArrived>?);"
return numberWithSQLAndParameters(sql, [feedID, articleCutoffDate], in: database)
}
func fetchArticlesForFeedID(_ feedID: String, withLimits: Bool, database: FMDatabase) -> Set<Article> {
return fetchArticlesWithWhereClause(database, whereClause: "articles.feedID = ?", parameters: [feedID as AnyObject], withLimits: withLimits)
}
func fetchUnreadArticles(_ feedIDs: Set<String>) -> Set<Article> {
if feedIDs.isEmpty {
return Set<Article>()
}
var articles = Set<Article>()
queue.fetchSync { (database) in
// select * from articles natural join statuses where feedID in ('http://ranchero.com/xml/rss.xml') and read=0
let parameters = feedIDs.map { $0 as AnyObject }
let placeholders = NSString.rs_SQLValueList(withPlaceholders: UInt(feedIDs.count))!
let whereClause = "feedID in \(placeholders) and read=0"
articles = self.fetchArticlesWithWhereClause(database, whereClause: whereClause, parameters: parameters, withLimits: true)
}
return articleCache.uniquedArticles(articles)
}
func articlesWithSQL(_ sql: String, _ parameters: [AnyObject], _ database: FMDatabase) -> Set<Article> {
guard let resultSet = database.executeQuery(sql, withArgumentsIn: parameters) else {
return Set<Article>()
}
return articlesWithResultSet(resultSet, database)
}
// MARK: Saving/Updating
func updateArticles(_ articlesDictionary: [String: Article], _ parsedItemsDictionary: [String: ParsedItem], _ feed: Feed, _ completion: @escaping RSVoidCompletionBlock) {
// 1. Fetch statuses for parsedItems.
// 2. Filter out parsedItems where userDeleted==1 or (arrival date > 4 months and not starred).
// (Under no user setting do we retain articles older with an arrival date > 4 months.)
// 3. Find parsedItems with no status and no matching article: save them as entirely new articles.
// 4. Compare remaining parsedItems with articles, and update database with any changes.
assert(Thread.isMainThread)
queue.fetch { (database) in
let parsedItemArticleIDs = Set(parsedItemsDictionary.keys)
let fetchedStatuses = self.statusesTable.fetchStatusesForArticleIDs(parsedItemArticleIDs, database)
DispatchQueue.main.async {
// #2. Drop any parsedItems that can be ignored.
// If thats all of them, then great  nothing to do.
let filteredParsedItems = self.filterParsedItems(parsedItemsDictionary, fetchedStatuses)
if filteredParsedItems.isEmpty {
completion()
return
}
// #3. Save entirely new parsedItems.
let newParsedItems = self.findNewParsedItems(parsedItemsDictionary, fetchedStatuses, articlesDictionary)
if !newParsedItems.isEmpty {
self.saveNewParsedItems(newParsedItems, feed)
}
// #4. Update existing parsedItems.
let parsedItemsToUpdate = self.findExistingParsedItems(parsedItemsDictionary, fetchedStatuses, articlesDictionary)
if !parsedItemsToUpdate.isEmpty {
self.updateParsedItems(parsedItemsToUpdate, articlesDictionary, feed)
}
completion()
}
}
}
func updateParsedItems(_ parsedItems: [String: ParsedItem], _ articles: [String: Article], _ feed: Feed) {
assert(Thread.isMainThread)
// updateRelatedObjects(_ parsedItems: [String: ParsedItem], _ articles: [String: Article])
}
// func updateRelatedObjects(_ parsedItems: [String: ParsedItem], _ articles: [String: Article]) {
//
// // Update the in-memory Articles when needed.
// // Save only when there are changes, which should be pretty infrequent.
//
// assert(Thread.isMainThread)
//
// var articlesWithTagChanges = Set<Article>()
// var articlesWithAttachmentChanges = Set<Article>()
// var articlesWithAuthorChanges = Set<Article>()
//
// for (articleID, parsedItem) in parsedItems {
//
// guard let article = articles[articleID] else {
// continue
// }
//
// if article.updateTagsWithParsedTags(parsedItem.tags) {
// articlesWithTagChanges.insert(article)
// }
// if article.updateAttachmentsWithParsedAttachments(parsedItem.attachments) {
// articlesWithAttachmentChanges.insert(article)
// }
// if article.updateAuthorsWithParsedAuthors(parsedItem.authors) {
// articlesWithAuthorChanges.insert(article)
// }
// }
//
// if articlesWithTagChanges.isEmpty && articlesWithAttachmentChanges.isEmpty && articlesWithAuthorChanges.isEmpty {
// // Should be pretty common.
// return
// }
//
// // We used detachedCopy because the Article objects being updated are main-thread objects.
//
// articlesWithTagChanges = Set(articlesWithTagChanges.map{ $0.detachedCopy() })
// articlesWithAttachmentChanges = Set(articlesWithAttachmentChanges.map{ $0.detachedCopy() })
// articlesWithAuthorChanges = Set(articlesWithAuthorChanges.map{ $0.detachedCopy() })
//
// queue.update { (database) in
// if !articlesWithTagChanges.isEmpty {
// tagsLookupTable.saveRelatedObjects(for: articlesWithTagChanges.databaseObjects(), in: database)
// }
// if !articlesWithAttachmentChanges.isEmpty {
// attachmentsLookupTable.saveRelatedObjects(for: articlesWithAttachmentChanges.databaseObjects(), in: database)
// }
// if !articlesWithAuthorChanges.isEmpty {
// authorsLookupTable.saveRelatedObjects(for: articlesWithAuthorChanges.databaseObjects(), in: database)
// }
// }
// }
// MARK: Save New Articles
func saveNewArticles(_ articles: Set<Article>, _ database: FMDatabase) {
saveRelatedObjectsForNewArticles(articles, database)
let databaseDictionaries = articles.map { $0.databaseDictionary() }
insertRows(databaseDictionaries, insertType: .orReplace, in: database)
}
func saveRelatedObjectsForNewArticles(_ articles: Set<Article>, _ database: FMDatabase) {
let databaseObjects = articles.databaseObjects()
authorsLookupTable.saveRelatedObjects(for: databaseObjects, in: database)
attachmentsLookupTable.saveRelatedObjects(for: databaseObjects, in: database)
tagsLookupTable.saveRelatedObjects(for: databaseObjects, in: database)
}
// MARK: Update Existing Articles
func articlesWithRelatedObjectChanges(_ comparisonKeyPath: Keypath<Article, Set<AnyHashable>>, _ updatedArticles: Set<Article>, _ fetchedArticles: [String: Article]) -> Set<Article> {
return updatedArticles.filter{ (updatedArticle) -> Bool in
if let fetchedArticle = fetchedArticles[updatedArticle.articleID] {
return updatedArticle[keyPath: comparisonKeyPath] != fetchedArticle[keyPath: comparisonKeyPath]
}
assertionFailure("Expected to find matching fetched article.");
return true
}
}
func updateRelatedObjects(_ comparisonKeyPath: Keypath<Article, Set<AnyHashable>>, _ updatedArticles: Set<Article>, _ fetchedArticles: [String: Article], _ lookupTable: DatabaseLookupTable, _ database: FMDatabase) {
let articlesWithChanges = articlesWithRelatedObjectChanges(comparisonKeyPath, updatedArticles, fetchedArticles)
if !articlesWithChanges.isEmpty {
lookupTable.saveRelatedObjects(for: articlesWithChanges.databaseObjects(), in: database)
}
}
func saveUpdatedRelatedObjects(_ updatedArticles: Set<Article>, _fetchedArticles: [String: Article], _ database: FMDatabase) {
updateRelatedObjects(\Article.tags, updatedArticles, fetchedArticles, tagsLookupTable, database)
updateRelatedObjects(\Article.authors, updatedArticles, fetchedArticles, authorsLookupTable, database)
updateRelatedObjects(\Article.attachments, updatedArticles, fetchedArticles, attachmentsLookupTable, database)
}
func saveUpdatedArticles(_ updatedArticles: Set<Article>, _ fetchedArticles: [String: Article], _ database: FMDatabase) {
updateRelatedTags(updatedArticles, fetchedArticles, database)
updateRelatedAttachments(updatedArticles, fetchedArticles, database)
updatedRelatedAuthors(updatedArticles, fetchedArticles, database)
}
func articlesWithParsedItems(_ parsedItems: Set<ParsedItem>, _ feed: Feed) -> Set<Article> {
assert(!Thread.isMainThread)
let feedID = feed.feedID
return Set(parsedItems.flatMap{ articleWithParsedItem($0, feedID) })
}
func articleWithParsedItem(_ parsedItem: ParsedItem, _ feedID: String) -> Article? {
return Article(parsedItem: parsedItem, feedID: feedID, accountID: accountID)
}
func statusIndicatesArticleIsIgnorable(_ status: ArticleStatus) -> Bool {
// Ignorable articles: either userDeleted==1 or (not starred and arrival date > 4 months).
if status.userDeleted {
return true
}
if status.starred {
return false
}
return status.dateArrived < maximumArticleCutoffDate
}
func filterParsedItems(_ parsedItems: [String: ParsedItem], _ statuses: [String: ArticleStatus]) -> [String: ParsedItem] {
// Drop parsedItems that we can ignore.
var d = [String: ParsedItem]()
for (articleID, parsedItem) in parsedItems {
if let status = statuses[articleID] {
if statusIndicatesArticleIsIgnorable(status) {
continue
}
}
d[articleID] = parsedItem
}
return d
}
func findNewParsedItems(_ parsedItems: [String: ParsedItem], _ statuses: [String: ArticleStatus], _ articles: [String: Article]) -> [String: ParsedItem] {
// If theres no existing status or Article, then its completely new.
assert(Thread.isMainThread)
var d = [String: ParsedItem]()
for (articleID, parsedItem) in parsedItems {
if statuses[articleID] == nil && articles[articleID] == nil {
d[articleID] = parsedItem
}
}
return d
}
func findExistingParsedItems(_ parsedItems: [String: ParsedItem], _ statuses: [String: ArticleStatus], _ articles: [String: Article]) -> [String: ParsedItem] {
return [String: ParsedItem]() //TODO
}
}