Continue transition from ODB to FeedMetadata.plist. It’s simpler and uses less memory.

Frameworks/Account/Account.swift

@@ -80,6 +80,15 @@ public final class Account: DisplayNameProvider, UnreadCountProvider, Container,
 	private var _flattenedFeeds = Set<Feed>()
 	private var flattenedFeedsNeedUpdate = true
 
+	private let feedMetadataPath: String
+	private typealias FeedMetadataDictionary = [String: FeedMetadata]
+	private var feedMetadata = FeedMetadataDictionary()
+	private var feedMetadataDirty = false {
+		didSet {
+			queueSaveMetadataIfNeeded()
+		}
+	}
+
 	private var startingUp = true
 
 	private struct SettingsKey {
@@ -137,6 +146,7 @@ public final class Account: DisplayNameProvider, UnreadCountProvider, Container,
 		let databaseFilePath = (dataFolder as NSString).appendingPathComponent("DB.sqlite3")
 		self.database = ArticlesDatabase(databaseFilePath: databaseFilePath, accountID: accountID)
 
+		self.feedMetadataPath = (dataFolder as NSString).appendingPathComponent("FeedMetadata.plist")
 		let settingsODBFilePath = (dataFolder as NSString).appendingPathComponent("Settings.odb")
 		self.settingsODB = ODB(filepath: settingsODBFilePath)
 		self.settingsODB.vacuum()
@@ -167,6 +177,17 @@ public final class Account: DisplayNameProvider, UnreadCountProvider, Container,
 		delegate.refreshAll(for: self)
 	}
 
+	func metadata(for feed: Feed) -> FeedMetadata {
+		if let d = feedMetadata[feed.feedID] {
+			assert(d.delegate === self)
+			return d
+		}
+		let d = FeedMetadata(feedID: feed.feedID)
+		d.delegate = self
+		feedMetadata[feed.feedID] = d
+		return d
+	}
+
 	public func update(_ feed: Feed, with parsedFeed: ParsedFeed, _ completion: @escaping RSVoidCompletionBlock) {
 
 		feed.takeSettings(from: parsedFeed)
@@ -559,6 +580,12 @@ public final class Account: DisplayNameProvider, UnreadCountProvider, Container,
 		}
 	}
 
+	@objc func saveMetadataIfNeeded() {
+		if feedMetadataDirty {
+			saveFeedMetadata()
+		}
+	}
+
 	// MARK: - Hashable
 
 	public func hash(into hasher: inout Hasher) {
@@ -590,6 +617,15 @@ extension Account {
 	}
 }
 
+// MARK: - FeedMetadataDelegate
+
+extension Account: FeedMetadataDelegate {
+
+	func valueDidChange(_ feedMetadata: FeedMetadata, key: FeedMetadata.CodingKeys) {
+		feedMetadataDirty = true
+	}
+}
+
 // MARK: - Disk (Private)
 
 private extension Account {
@@ -614,7 +650,7 @@ private extension Account {
 	}
 
 	func pullObjectsFromDisk() {
-
+		
 		// 9/16/2018: Turning a corner — we used to store data in a plist file,
 		// but now we’re switching over to OPML. Read the plist file one last time,
 		// then rename it so we never read from it again.
@@ -654,9 +690,20 @@ private extension Account {
 			return
 		}
 
+		importFeedMetadata()
 		importOPMLFile(path: opmlFilePath)
 	}
 
+	func importFeedMetadata() {
+		let url = URL(fileURLWithPath: feedMetadataPath)
+		guard let data = try? Data(contentsOf: url) else {
+			return
+		}
+		let decoder = PropertyListDecoder()
+		feedMetadata = (try? decoder.decode(FeedMetadataDictionary.self, from: data)) ?? FeedMetadataDictionary()
+		feedMetadata.values.forEach { $0.delegate = self }
+	}
+
 	func importOPMLFile(path: String) {
 		let opmlFileURL = URL(fileURLWithPath: path)
 		var fileData: Data?
@@ -703,6 +750,33 @@ private extension Account {
 			NSApplication.shared.presentError(error)
 		}
 	}
+
+	func queueSaveMetadataIfNeeded() {
+		Account.saveQueue.add(self, #selector(saveMetadataIfNeeded))
+	}
+
+	private func metadataForOnlySubscribedToFeeds() -> FeedMetadataDictionary {
+		let feedIDs = idToFeedDictionary.keys
+		return feedMetadata.filter { (feedID: String, metadata: FeedMetadata) -> Bool in
+			return feedIDs.contains(feedID)
+		}
+	}
+
+	func saveFeedMetadata() {
+		feedMetadataDirty = false
+
+		let d = metadataForOnlySubscribedToFeeds()
+		let encoder = PropertyListEncoder()
+		encoder.outputFormat = .binary
+		let url = URL(fileURLWithPath: feedMetadataPath)
+		do {
+			let data = try encoder.encode(d)
+			try data.write(to: url)
+		}
+		catch {
+			assertionFailure(error.localizedDescription)
+		}
+	}
 }
 
 // MARK: - Private

Frameworks/Account/Feed.swift

@@ -35,33 +35,33 @@ public final class Feed: DisplayNameProvider, Renamable, UnreadCountProvider, Ha
 
 	public var homePageURL: String? {
 		get {
-			return settingsTable.string(for: Key.homePageURL)
+			return metadata?.homePageURL
 		}
 		set {
 			if let url = newValue {
-				settingsTable.setString(url.rs_normalizedURL(), for: Key.homePageURL)
+				metadata?.homePageURL = url.rs_normalizedURL()
 			}
 			else {
-				settingsTable.setString(nil, for: Key.homePageURL)
+				metadata?.homePageURL = nil
 			}
 		}
 	}
 
 	public var iconURL: String? {
 		get {
-			return settingsTable.string(for: Key.iconURL)
+			return metadata?.iconURL
 		}
 		set {
-			settingsTable.setString(newValue, for: Key.iconURL)
+			metadata?.iconURL = newValue
 		}
 	}
 
 	public var faviconURL: String? {
 		get {
-			return settingsTable.string(for: Key.faviconURL)
+			return metadata?.faviconURL
 		}
 		set {
-			settingsTable.setString(newValue, for: Key.faviconURL)
+			metadata?.faviconURL = newValue
 		}
 	}
 
@@ -80,17 +80,17 @@ public final class Feed: DisplayNameProvider, Renamable, UnreadCountProvider, Ha
 
 	public var authors: Set<Author>? {
 		get {
-			guard let authorsJSON = settingsTable.string(for: Key.authors) else {
+			if let authorsArray = metadata?.authors {
-				return nil
+				return Set(authorsArray)
 			}
-			return Author.authorsWithJSON(authorsJSON)
+			return nil
 		}
 		set {
-			if let authorsJSON = newValue?.json() {
+			if let authorsSet = newValue {
-				settingsTable.setString(authorsJSON, for: Key.authors)
+				metadata?.authors = Array(authorsSet)
 			}
 			else {
-				settingsTable.setString(nil, for: Key.authors)
+				metadata?.authors = nil
 			}
 		}
 	}
@@ -118,22 +118,19 @@ public final class Feed: DisplayNameProvider, Renamable, UnreadCountProvider, Ha
 
 	public var conditionalGetInfo: HTTPConditionalGetInfo? {
 		get {
-			let lastModified = settingsTable.string(for: Key.conditionalGetLastModified)
+			return metadata?.conditionalGetInfo
-			let etag = settingsTable.string(for: Key.conditionalGetEtag)
-			return HTTPConditionalGetInfo(lastModified: lastModified, etag: etag)
 		}
 		set {
-			settingsTable.setString(newValue?.lastModified, for: Key.conditionalGetLastModified)
+			metadata?.conditionalGetInfo = newValue
-			settingsTable.setString(newValue?.etag, for: Key.conditionalGetEtag)
 		}
 	}
 
 	public var contentHash: String? {
 		get {
-			return settingsTable.string(for: Key.contentHash)
+			return metadata?.contentHash
 		}
 		set {
-			settingsTable.setString(newValue, for: Key.contentHash)
+			metadata?.contentHash = newValue
 		}
 	}
 
@@ -173,6 +170,15 @@ public final class Feed: DisplayNameProvider, Renamable, UnreadCountProvider, Ha
 	private let settingsTable: ODBRawValueTable
 	private let accountID: String // Used for hashing and equality; account may turn nil
 
+	private var _metadata: FeedMetadata?
+	private var metadata: FeedMetadata? {
+		if let cachedMetadata = _metadata {
+			return cachedMetadata
+		}
+		_metadata = account?.metadata(for: self)
+		return _metadata
+	}
+
 	// MARK: - Init
 
 	public init(account: Account, url: String, feedID: String) {

Frameworks/Account/FeedMetadata.swift

@@ -96,9 +96,8 @@ final class FeedMetadata: Codable {
 
 	weak var delegate: FeedMetadataDelegate?
 
-	init(feedID: String, delegate: FeedMetadataDelegate) {
+	init(feedID: String) {
 		self.feedID = feedID
-		self.delegate = delegate
 	}
 
 	func valueDidChange(_ key: CodingKeys) {