Save and fetch attachments. Use a cache.

Frameworks/Data/Attachment.swift

@@ -23,8 +23,18 @@ public struct Attachment: Hashable {
 		self.url = url
 		self.mimeType = mimeType
 		self.title = title
-		self.sizeInBytes = sizeInBytes
-		self.durationInSeconds = durationInSeconds
+		if let sizeInBytes = sizeInBytes, sizeInBytes > 0 {
+			self.sizeInBytes = sizeInBytes
+		}
+		else {
+			self.sizeInBytes = nil
+		}
+		if let durationInSeconds = durationInSeconds, durationInSeconds > 0 {
+			self.durationInSeconds = durationInSeconds
+		}
+		else {
+			self.durationInSeconds = nil
+		}
 
 		var s = url
 		s += mimeType ?? ""

Frameworks/Database/AttachmentsTable.swift

@@ -14,14 +14,48 @@ final class AttachmentsTable: DatabaseRelatedObjectsTable {
 
 	let name: String
 	let databaseIDKey = DatabaseKey.attachmentID
+	var cache = [String: Attachment]()
 
 	init(name: String) {
 
 		self.name = name
 	}
 	
-	// MARK: DatabaseTable Methods
-	
+	// MARK: DatabaseRelatedObjectsTable
+
+	func fetchObjectsWithIDs(_ databaseIDs: Set<String>, in database: FMDatabase) -> [DatabaseObject]? {
+
+		if databaseIDs.isEmpty {
+			return nil
+		}
+
+		var cachedAttachments = Set<Attachment>()
+		var databaseIDsToFetch = Set<String>()
+
+		for attachmentID in databaseIDs {
+			if let cachedAttachment = cache[attachmentID] {
+				cachedAttachments.insert(cachedAttachment)
+			}
+			else {
+				databaseIDsToFetch.insert(attachmentID)
+			}
+		}
+
+		if databaseIDsToFetch.isEmpty {
+			return cachedAttachments.databaseObjects()
+		}
+
+		guard let resultSet = selectRowsWhere(key: databaseIDKey, inValues: Array(databaseIDsToFetch), in: database) else {
+			return cachedAttachments.databaseObjects()
+		}
+		let fetchedDatabaseObjects = objectsWithResultSet(resultSet)
+		let fetchedAttachments = Set(fetchedDatabaseObjects.map { $0 as Attachment })
+		cacheAttachments(fetchedAttachments)
+
+		let allAttachments = cachedAttachments.union(fetchedAttachments)
+		return allAttachments.databaseObjects()
+	}
+
 	func objectWithRow(_ row: FMResultSet) -> DatabaseObject? {
 		
 		if let attachment = attachmentWithRow(row) {
@@ -31,17 +65,37 @@ final class AttachmentsTable: DatabaseRelatedObjectsTable {
 	}
 	
 	func save(_ objects: [DatabaseObject], in database: FMDatabase) {
-		// TODO
+
+		let attachments = objects.map { $0 as! Attachment }
+
+		// Attachments in cache must already exist in database. Filter them out.
+		let attachmentsToSave = Set(attachments.filter { (attachment) -> Bool in
+			if let _ = cache[attachment.attachmentID] {
+				return false
+			}
+			return true
+		})
+
+		cacheAttachments(attachmentsToSave)
+		
+		insertRows(attachmentsToSave.databaseDictionaries(), insertType: .orIgnore, in: database)
 	}
 }
 
 private extension AttachmentsTable {
 
+	func cacheAttachments(_ attachments: Set<Attachment>) {
+
+		for attachment in attachments {
+			cache[attachment.attachmentID] = attachment
+		}
+	}
+
 	func attachmentWithRow(_ row: FMResultSet) -> Attachment? {
 
-		guard let attachmentID = row.string(forColumn: DatabaseKey.attachmentID) else {
-			return nil
-		}
+		// attachmentID is non-null in database schema.
+		let attachmentID = row.string(forColumn: DatabaseKey.attachmentID)!
 		return Attachment(attachmentID: attachmentID, row: row)
 	}
 }
+

Frameworks/Database/Extensions/Attachment+Database.swift

@@ -41,6 +41,29 @@ extension Attachment {
 		let attachments = parsedAttachments.flatMap{ Attachment(parsedAttachment: $0) }
 		return attachments.isEmpty ? nil : Set(attachments)
 	}
+
+	func databaseDictionary() -> NSDictionary {
+
+		var d = NSMutableDictionary()
+
+		d[DatabaseKey.attachmentID] = attachmentID
+		d[DatabaseKey.url] = url
+
+		if let mimeType = mimeType {
+			d[DatabaseKey.mimeType] = mimeType
+		}
+		if let title = title {
+			d[DatabaseKey.title] = title
+		}
+		if let sizeInBytes = sizeInBytes {
+			d[DatabaseKey.sizeInBytes] = NSNumber(sizeInBytes)
+		}
+		if let durationInSeconds = durationInSeconds {
+			d[DatabaseKey.durationInSeconds] = NSNumber(durationInSeconds)
+		}
+
+		return d.copy() as! NSDictionary
+	}
 }
 
 private func optionalIntForColumn(_ row: FMResultSet, _ columnName: String) -> Int? {
@@ -60,3 +83,16 @@ extension Attachment: DatabaseObject {
 		}
 	}
 }
+
+extension Set where Element == Attachment {
+
+	func databaseDictionaries() -> [NSDictionary] {
+
+		return self.map<NSDictionary> { $0.databaseDictionary() }
+	}
+
+	func databaseObjects() -> [DatabaseObject] {
+
+		return self.map<DatabaseObject> { $0 as DatabaseObject }
+	}
+}

Frameworks/Database/TagsTable.swift

@@ -28,7 +28,7 @@ final class TagsTable: DatabaseRelatedObjectsTable {
 
 	// MARK: DatabaseTable Methods
 	
-	func fetchObjectsWithIDs(_ databaseIDs: Set<String>, in database: FMDatabase) -> [DatabaseObject] {
+	func fetchObjectsWithIDs(_ databaseIDs: Set<String>, in database: FMDatabase) -> [DatabaseObject]? {
 		
 		// A tag is a string, and it is its own databaseID.
 		return databaseIDs.map{ $0 as DatabaseObject }
@@ -43,6 +43,5 @@ final class TagsTable: DatabaseRelatedObjectsTable {
 		
 		// Nothing to do, since tags are saved in the lookup table, not in a separate table.
 	}
-
 }
 

Frameworks/RSDatabase/RSDatabase/DatabaseObject.swift

@@ -12,16 +12,11 @@ public protocol DatabaseObject {
 
 	var databaseID: String { get }
 
-	func setRelatedObjects(_ objects: [DatabaseObject], name: String)
 	func relatedObjectsWithName(_ name: String) -> [DatabaseObject]?
 }
 
 public extension DatabaseObject {
 	
-	func setRelatedObjects(_ objects: [DatabaseObject], name: String) {
-		// Do nothing
-	}
-	
 	func relatedObjectsWithName(_ name: String) -> [DatabaseObject]? {
 		
 		return nil

Frameworks/RSDatabase/Related Objects/DatabaseLookupTable.swift

@@ -183,8 +183,7 @@ private extension DatabaseLookupTable {
 	
 	func fetchRelatedObjectsWithIDs(_ relatedObjectIDs: Set<String>, _ database: FMDatabase) -> [DatabaseObject]? {
 		
-		let relatedObjects = relatedTable.fetchObjectsWithIDs(relatedObjectIDs, in: database)
-		if relatedObjects.isEmpty {
+		guard let relatedObjects = relatedTable.fetchObjectsWithIDs(relatedObjectIDs, in: database), !relatedObjects.isEmpty else {
 			return nil
 		}
 		return relatedObjects

Frameworks/RSDatabase/Related Objects/DatabaseRelatedObjectsTable.swift

@@ -14,7 +14,7 @@ public protocol DatabaseRelatedObjectsTable: DatabaseTable {
 
 	var databaseIDKey: String { get}
 
-	func fetchObjectsWithIDs(_ databaseIDs: Set<String>, in database: FMDatabase) -> [DatabaseObject]
+	func fetchObjectsWithIDs(_ databaseIDs: Set<String>, in database: FMDatabase) -> [DatabaseObject]?
 	func objectsWithResultSet(_ resultSet: FMResultSet) -> [DatabaseObject]
 	func objectWithRow(_ row: FMResultSet) -> DatabaseObject?
 
@@ -25,10 +25,10 @@ public extension DatabaseRelatedObjectsTable {
 
 	// MARK: Default implementations
 
-	func fetchObjectsWithIDs(_ databaseIDs: Set<String>, in database: FMDatabase) -> [DatabaseObject] {
+	func fetchObjectsWithIDs(_ databaseIDs: Set<String>, in database: FMDatabase) -> [DatabaseObject]? {
 
 		guard let resultSet = selectRowsWhere(key: databaseIDKey, inValues: Array(databaseIDs), in: database) else {
-			return [DatabaseObject]()
+			return nil
 		}
 		return objectsWithResultSet(resultSet)
 	}