Index articles using SQLite FTS.

Frameworks/ArticlesDatabase/ArticlesDatabase.swift

@@ -38,6 +38,9 @@ public final class ArticlesDatabase {
 			database.executeStatements("DROP TABLE if EXISTS tags;DROP INDEX if EXISTS tags_tagName_index;DROP INDEX if EXISTS articles_feedID_index;DROP INDEX if EXISTS statuses_read_index;")
 		}
 		queue.vacuumIfNeeded()
+		DispatchQueue.main.async {
+			self.articlesTable.indexUnindexedArticles()
+		}
 	}
 
 	// MARK: - Fetching Articles

Frameworks/ArticlesDatabase/ArticlesDatabase.xcodeproj/project.pbxproj

@@ -21,6 +21,7 @@
 		845580761F0AF670003CCFA1 /* Article+Database.swift in Sources */ = {isa = PBXBuildFile; fileRef = 845580751F0AF670003CCFA1 /* Article+Database.swift */; };
 		8455807A1F0AF67D003CCFA1 /* ArticleStatus+Database.swift in Sources */ = {isa = PBXBuildFile; fileRef = 845580791F0AF67D003CCFA1 /* ArticleStatus+Database.swift */; };
 		8455807C1F0C0DBD003CCFA1 /* Attachment+Database.swift in Sources */ = {isa = PBXBuildFile; fileRef = 8455807B1F0C0DBD003CCFA1 /* Attachment+Database.swift */; };
+		8477ACBC2221E76F00DF7F37 /* SearchTable.swift in Sources */ = {isa = PBXBuildFile; fileRef = 8477ACBB2221E76F00DF7F37 /* SearchTable.swift */; };
 		848AD2961F58A91E004FB0EC /* UnreadCountDictionary.swift in Sources */ = {isa = PBXBuildFile; fileRef = 848AD2951F58A91E004FB0EC /* UnreadCountDictionary.swift */; };
 		848E3EB920FBCFD20004B7ED /* RSCore.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 848E3EB820FBCFD20004B7ED /* RSCore.framework */; };
 		848E3EBB20FBCFD80004B7ED /* RSParser.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 848E3EBA20FBCFD80004B7ED /* RSParser.framework */; };
@@ -128,6 +129,7 @@
 		845580791F0AF67D003CCFA1 /* ArticleStatus+Database.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; name = "ArticleStatus+Database.swift"; path = "Extensions/ArticleStatus+Database.swift"; sourceTree = "<group>"; };
 		8455807B1F0C0DBD003CCFA1 /* Attachment+Database.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; name = "Attachment+Database.swift"; path = "Extensions/Attachment+Database.swift"; sourceTree = "<group>"; };
 		8461461E1F0ABC7300870CB3 /* RSParser.xcodeproj */ = {isa = PBXFileReference; lastKnownFileType = "wrapper.pb-project"; name = RSParser.xcodeproj; path = ../RSParser/RSParser.xcodeproj; sourceTree = "<group>"; };
+		8477ACBB2221E76F00DF7F37 /* SearchTable.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SearchTable.swift; sourceTree = "<group>"; };
 		848AD2951F58A91E004FB0EC /* UnreadCountDictionary.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = UnreadCountDictionary.swift; sourceTree = "<group>"; };
 		848E3EB820FBCFD20004B7ED /* RSCore.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; path = RSCore.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		848E3EBA20FBCFD80004B7ED /* RSParser.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; path = RSParser.framework; sourceTree = BUILT_PRODUCTS_DIR; };
@@ -178,6 +180,7 @@
 				848AD2951F58A91E004FB0EC /* UnreadCountDictionary.swift */,
 				845580661F0AEBCD003CCFA1 /* Constants.swift */,
 				84E156EB1F0AB80E00F8CC05 /* ArticlesTable.swift */,
+				8477ACBB2221E76F00DF7F37 /* SearchTable.swift */,
 				843577151F744FC800F460AE /* DatabaseArticle.swift */,
 				84E156ED1F0AB81400F8CC05 /* StatusesTable.swift */,
 				84F20F8E1F180D8700D8E682 /* AuthorsTable.swift */,
@@ -503,6 +506,7 @@
 				840405CF1F1A963700DF0296 /* AttachmentsTable.swift in Sources */,
 				84F20F8F1F180D8700D8E682 /* AuthorsTable.swift in Sources */,
 				84288A001F6A3C4400395871 /* DatabaseObject+Database.swift in Sources */,
+				8477ACBC2221E76F00DF7F37 /* SearchTable.swift in Sources */,
 				843577161F744FC800F460AE /* DatabaseArticle.swift in Sources */,
 				843702C31F70D15D00B18807 /* ParsedArticle+Database.swift in Sources */,
 				84E156EC1F0AB80E00F8CC05 /* ArticlesTable.swift in Sources */,

Frameworks/ArticlesDatabase/ArticlesTable.swift

@@ -21,6 +21,10 @@ final class ArticlesTable: DatabaseTable {
 	private let authorsLookupTable: DatabaseLookupTable
 	private let attachmentsLookupTable: DatabaseLookupTable
 
+	private lazy var searchTable: SearchTable = {
+		return SearchTable(queue: queue, articlesTable: self)
+	}()
+
 	// 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)!
@@ -31,7 +35,7 @@ final class ArticlesTable: DatabaseTable {
 		self.accountID = accountID
 		self.queue = queue
 		self.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)
 		
@@ -88,6 +92,31 @@ final class ArticlesTable: DatabaseTable {
 		}
 	}
 
+	func fetchArticleSearchInfos(_ articleIDs: Set<String>, in database: FMDatabase) -> Set<ArticleSearchInfo>? {
+		let parameters = articleIDs.map { $0 as AnyObject }
+		let placeholders = NSString.rs_SQLValueList(withPlaceholders: UInt(articleIDs.count))!
+		let sql = "select articleID, title, contentHTML, contentText, summary, searchRowID from articles where articleID in \(placeholders);";
+
+		if let resultSet = database.executeQuery(sql, withArgumentsIn: parameters) {
+			return resultSet.mapToSet { (row) -> ArticleSearchInfo? in
+				let articleID = row.string(forColumn: DatabaseKey.articleID)!
+				let title = row.string(forColumn: DatabaseKey.title)
+				let contentHTML = row.string(forColumn: DatabaseKey.contentHTML)
+				let contentText = row.string(forColumn: DatabaseKey.contentText)
+				let summary = row.string(forColumn: DatabaseKey.summary)
+
+				let searchRowIDObject = row.object(forColumnName: DatabaseKey.searchRowID)
+				var searchRowID: Int? = nil
+				if searchRowIDObject != nil && !(searchRowIDObject is NSNull) {
+					searchRowID = Int(row.longLongInt(forColumn: DatabaseKey.searchRowID))
+				}
+
+				return ArticleSearchInfo(articleID: articleID, title: title, contentHTML: contentHTML, contentText: contentText, summary: summary, searchRowID: searchRowID)
+			}
+		}
+		return nil
+	}
+
 	// MARK: Updating
 	
 	func update(_ feedID: String, _ parsedFeed: ParsedFeed, _ completion: @escaping UpdateArticlesWithFeedCompletionBlock) {
@@ -104,7 +133,8 @@ final class ArticlesTable: DatabaseTable {
 		// 5. Create array of Articles not in database and save them.
 		// 6. Create array of updated Articles and save what’s changed.
 		// 7. Call back with new and updated Articles.
-		
+		// 8. Update search index.
+
 		let articleIDs = Set(parsedFeed.items.map { $0.articleID })
 		
 		self.queue.update { (database) in
@@ -131,6 +161,22 @@ final class ArticlesTable: DatabaseTable {
 			let updatedArticles = self.findAndSaveUpdatedArticles(incomingArticles, fetchedArticlesDictionary, database) //6
 			
 			self.callUpdateArticlesCompletionBlock(newArticles, updatedArticles, completion) //7
+
+			// 8. Update search index.
+			var articlesToIndex = Set<Article>()
+			if let newArticles = newArticles {
+				articlesToIndex.formUnion(newArticles)
+			}
+			if let updatedArticles = updatedArticles {
+				articlesToIndex.formUnion(updatedArticles)
+			}
+			let articleIDs = articlesToIndex.articleIDs()
+			if articleIDs.isEmpty {
+				return
+			}
+			DispatchQueue.main.async() {
+				self.searchTable.ensureIndexedArticles(for: articleIDs)
+			}
 		}
 	}
 
@@ -247,6 +293,26 @@ final class ArticlesTable: DatabaseTable {
 
 		return statusesTable.markEverywhereAsRead()
 	}
+
+	// MARK: Indexing
+
+	func indexUnindexedArticles() {
+		queue.fetch { (database) in
+			let sql = "select articleID from articles where searchRowID is null limit 500;"
+			guard let resultSet = database.executeQuery(sql, withArgumentsIn: nil) else {
+				return
+			}
+			let articleIDs = resultSet.mapToSet{ $0.string(forColumn: DatabaseKey.articleID) }
+			if articleIDs.isEmpty {
+				return
+			}
+			self.searchTable.ensureIndexedArticles(for: articleIDs)
+
+			DispatchQueue.main.async {
+				self.indexUnindexedArticles()
+			}
+		}
+	}
 }
 
 // MARK: - Private

Frameworks/ArticlesDatabase/Constants.swift

@@ -40,6 +40,7 @@ struct DatabaseKey {
 	static let dateModified = "dateModified"
 	static let authors = "authors"
 	static let attachments = "attachments"
+	static let searchRowID = "searchRowID"
 	
 	// ArticleStatus
 	static let read = "read"
@@ -61,6 +62,10 @@ struct DatabaseKey {
 	static let name = "name"
 	static let avatarURL = "avatarURL"
 	static let emailAddress = "emailAddress"
+
+	// Search
+	static let body = "body"
+	static let rowID = "rowid"
 }
 
 struct RelationshipName {

Frameworks/ArticlesDatabase/DatabaseArticle.swift

@@ -28,16 +28,17 @@ struct DatabaseArticle: Hashable {
 	let datePublished: Date?
 	let dateModified: Date?
 	let status: ArticleStatus
-	var hashValue: Int {
-		return articleID.hashValue
+
+	// MARK: - Hashable
+
+	public func hash(into hasher: inout Hasher) {
+		hasher.combine(articleID)
 	}
 }
 
-
 extension Set where Element == DatabaseArticle {
 
 	func articleIDs() -> Set<String> {
-
 		return Set<String>(map { $0.articleID })
 	}
 }

Frameworks/ArticlesDatabase/SearchTable.swift

@@ -0,0 +1,193 @@
+//
+//  SearchTable.swift
+//  ArticlesDatabase
+//
+//  Created by Brent Simmons on 2/23/19.
+//  Copyright © 2019 Ranchero Software. All rights reserved.
+//
+
+import Foundation
+import RSCore
+import RSDatabase
+import Articles
+import RSParser
+
+final class ArticleSearchInfo: Hashable {
+
+	let articleID: String
+	let title: String?
+	let contentHTML: String?
+	let contentText: String?
+	let summary: String?
+	let searchRowID: Int?
+	
+	var preferredText: String {
+		if let body = contentHTML, !body.isEmpty {
+			return body
+		}
+		if let body = contentText, !body.isEmpty {
+			return body
+		}
+		return summary ?? ""
+	}
+
+	lazy var bodyForIndex: String = {
+		let s = preferredText.rsparser_stringByDecodingHTMLEntities()
+		return s.rs_string(byStrippingHTML: 0).rs_stringWithCollapsedWhitespace()
+	}()
+
+	init(articleID: String, title: String?, contentHTML: String?, contentText: String?, summary: String?, searchRowID: Int?) {
+		self.articleID = articleID
+		self.title = title
+		self.contentHTML = contentHTML
+		self.contentText = contentText
+		self.summary = summary
+		self.searchRowID = searchRowID
+	}
+
+	// MARK: Hashable
+
+	public func hash(into hasher: inout Hasher) {
+		hasher.combine(articleID)
+	}
+
+	// MARK: Equatable
+
+	static func == (lhs: ArticleSearchInfo, rhs: ArticleSearchInfo) -> Bool {
+		return lhs.articleID == rhs.articleID && lhs.title == rhs.title && lhs.contentHTML == rhs.contentHTML && lhs.contentText == rhs.contentText && lhs.summary == rhs.summary && lhs.searchRowID == rhs.searchRowID
+	}
+}
+
+final class SearchTable: DatabaseTable {
+
+	let name = "search"
+	private let queue: RSDatabaseQueue
+	private weak var articlesTable: ArticlesTable?
+
+	init(queue: RSDatabaseQueue, articlesTable: ArticlesTable) {
+		self.queue = queue
+		self.articlesTable = articlesTable
+	}
+
+	func ensureIndexedArticles(for articleIDs: Set<String>) {
+		if articleIDs.isEmpty {
+			return
+		}
+		queue.update { (database) in
+			self.ensureIndexedArticles(articleIDs, database)
+		}
+	}
+}
+
+// MARK: - Private
+
+private extension SearchTable {
+
+	func ensureIndexedArticles(_ articleIDs: Set<String>, _ database: FMDatabase) {
+		guard let articlesTable = articlesTable else {
+			return
+		}
+		guard let articleSearchInfos = articlesTable.fetchArticleSearchInfos(articleIDs, in: database) else {
+			return
+		}
+
+		let unindexedArticles = articleSearchInfos.filter { $0.searchRowID == nil }
+		performInitialIndexForArticles(unindexedArticles, database)
+
+		let indexedArticles = articleSearchInfos.filter { $0.searchRowID != nil }
+		updateIndexForArticles(indexedArticles, database)
+	}
+
+	func performInitialIndexForArticles(_ articles: Set<ArticleSearchInfo>, _ database: FMDatabase) {
+		articles.forEach { performInitialIndex($0, database) }
+	}
+
+	func performInitialIndex(_ article: ArticleSearchInfo, _ database: FMDatabase) {
+		let rowid = insert(article, database)
+		articlesTable?.updateRowsWithValue(rowid, valueKey: DatabaseKey.searchRowID, whereKey: DatabaseKey.articleID, matches: [article.articleID], database: database)
+	}
+
+	func insert(_ article: ArticleSearchInfo, _ database: FMDatabase) -> Int {
+		let rowDictionary = NSMutableDictionary()
+		rowDictionary.setObject(article.title ?? "", forKey: DatabaseKey.title as NSString)
+		rowDictionary.setObject(article.bodyForIndex, forKey: DatabaseKey.body as NSString)
+		insertRow(rowDictionary, insertType: .normal, in: database)
+		return Int(database.lastInsertRowId())
+	}
+
+	private struct SearchInfo: Hashable {
+		let rowID: Int
+		let title: String
+		let body: String
+
+		init(row: FMResultSet) {
+			self.rowID = Int(row.longLongInt(forColumn: DatabaseKey.rowID))
+			self.title = row.string(forColumn: DatabaseKey.title) ?? ""
+			self.body = row.string(forColumn: DatabaseKey.body) ?? ""
+		}
+
+		// MARK: Hashable
+
+		public func hash(into hasher: inout Hasher) {
+			hasher.combine(rowID)
+		}
+	}
+
+	func updateIndexForArticles(_ articles: Set<ArticleSearchInfo>, _ database: FMDatabase) {
+		if articles.isEmpty {
+			return
+		}
+		guard let searchInfos = fetchSearchInfos(articles, database) else {
+			// The articles that get here have a non-nil searchRowID, and we should have found rows in the search table for them.
+			// But we didn’t. Recover by doing an initial index.
+			performInitialIndexForArticles(articles, database)
+			return
+		}
+		let groupedSearchInfos = Dictionary(grouping: searchInfos, by: { $0.rowID })
+		let searchInfosDictionary = groupedSearchInfos.mapValues { $0.first! }
+
+		articles.forEach { (article) in
+			updateIndexForArticle(article, searchInfosDictionary, database)
+		}
+	}
+
+	private func updateIndexForArticle(_ article: ArticleSearchInfo, _ searchInfosDictionary: [Int: SearchInfo], _ database: FMDatabase) {
+		guard let searchRowID = article.searchRowID else {
+			assertionFailure("Expected article.searchRowID, got nil")
+			return
+		}
+		guard let searchInfo: SearchInfo = searchInfosDictionary[searchRowID] else {
+			// Shouldn’t happen. The article has a searchRowID, but we didn’t find that row in the search table.
+			// Easy to recover from: just do an initial index, and all’s well.
+			performInitialIndex(article, database)
+			return
+		}
+
+		let title = article.title ?? ""
+		if title == searchInfo.title && article.bodyForIndex == searchInfo.body {
+			return
+		}
+
+		let updateDictionary = NSMutableDictionary()
+		if title != searchInfo.title {
+			updateDictionary.setObject(title, forKey: DatabaseKey.title as NSString)
+		}
+		if article.bodyForIndex != searchInfo.body {
+			updateDictionary.setObject(article.bodyForIndex, forKey: DatabaseKey.body as NSString)
+		}
+		updateRowsWithDictionary(updateDictionary, whereKey: DatabaseKey.rowID, matches: searchInfo.rowID, database: database)
+	}
+
+	private func fetchSearchInfos(_ articles: Set<ArticleSearchInfo>, _ database: FMDatabase) -> Set<SearchInfo>? {
+		let searchRowIDs = articles.compactMap { $0.searchRowID }
+		guard !searchRowIDs.isEmpty else {
+			return nil
+		}
+		let placeholders = NSString.rs_SQLValueList(withPlaceholders: UInt(searchRowIDs.count))!
+		let sql = "select rowid, title, body from \(name) where rowid in \(placeholders);"
+		guard let resultSet = database.executeQuery(sql, withArgumentsIn: searchRowIDs) else {
+			return nil
+		}
+		return resultSet.mapToSet { SearchInfo(row: $0) }
+	}
+}