Validate messages after receiving

SessionMessagingKit/Messages/Control Message/ClosedGroupUpdate.swift

@@ -20,7 +20,7 @@ public final class ClosedGroupUpdate : ControlMessage {
     }
 
     // MARK: Validation
-    public override var isValidForSending: Bool { kind != nil }
+    public override var isValid: Bool { kind != nil }
 
     // MARK: Coding
     public required init?(coder: NSCoder) {

SessionMessagingKit/Messages/Control Message/ExpirationTimerUpdate.swift

@@ -11,7 +11,7 @@ public final class ExpirationTimerUpdate : ControlMessage {
     }
 
     // MARK: Validation
-    public override var isValidForSending: Bool { duration != nil }
+    public override var isValid: Bool { duration != nil }
 
     // MARK: Coding
     public required init?(coder: NSCoder) {

SessionMessagingKit/Messages/Control Message/ReadReceipt.swift

@@ -11,7 +11,7 @@ public final class ReadReceipt : ControlMessage {
     }
 
     // MARK: Validation
-    public override var isValidForSending: Bool {
+    public override var isValid: Bool {
         if let timestamps = timestamps, !timestamps.isEmpty { return true }
         return false
     }

SessionMessagingKit/Messages/Control Message/SessionRequest.swift

@@ -12,7 +12,7 @@ public final class SessionRequest : ControlMessage {
     }
 
     // MARK: Validation
-    public override var isValidForSending: Bool { preKeyBundle != nil }
+    public override var isValid: Bool { preKeyBundle != nil }
 
     // MARK: Coding
     public required init?(coder: NSCoder) {

SessionMessagingKit/Messages/Control Message/TypingIndicator.swift

@@ -24,7 +24,7 @@ public final class TypingIndicator : ControlMessage {
     }
 
     // MARK: Validation
-    public override var isValidForSending: Bool { kind != nil }
+    public override var isValid: Bool { kind != nil }
 
     // MARK: Initialization
     internal init(kind: Kind) {

SessionMessagingKit/Messages/Message.swift

@@ -11,7 +11,7 @@ public class Message : NSObject, NSCoding { // Not a protocol for YapDatabase co
     public override init() { }
 
     // MARK: Validation
-    public var isValidForSending: Bool { true }
+    public var isValid: Bool { true }
 
     // MARK: Coding
     public required init?(coder: NSCoder) {

SessionMessagingKit/Messages/Visible Message/VisibleMessage.swift

@@ -13,7 +13,7 @@ public final class VisibleMessage : Message {
     public override init() { super.init() }
 
     // MARK: Validation
-    public override var isValidForSending: Bool {
+    public override var isValid: Bool {
         if !attachmentIDs.isEmpty { return true }
         if let text = text?.trimmingCharacters(in: .whitespacesAndNewlines), !text.isEmpty { return true }
         return false

SessionMessagingKit/Pipelines/ReceivingPipeline.swift

@@ -2,22 +2,39 @@ import SessionUtilities
 
 public enum ReceivingPipeline {
 
-    public static func parse(_ data: Data) -> Message? {
-        // TODO: Decryption
-        // TODO: Validation
+    public enum Error : LocalizedError {
+        case invalidMessage
+
+        public var errorDescription: String? {
+            switch self {
+            case .invalidMessage: return "Invalid message."
+            }
+        }
+    }
+
+    public static func parse(_ ciphertext: Data) -> Message? {
+        let plaintext = ciphertext // TODO: Decryption
         let proto: SNProtoContent
         do {
-            proto = try SNProtoContent.parseData(data)
+            proto = try SNProtoContent.parseData(plaintext)
         } catch {
             SNLog("Couldn't parse proto due to error: \(error).")
             return nil
         }
-        if let readReceipt = ReadReceipt.fromProto(proto) { return readReceipt }
-        if let sessionRequest = SessionRequest.fromProto(proto) { return sessionRequest }
-        if let typingIndicator = TypingIndicator.fromProto(proto) { return typingIndicator }
-        if let closedGroupUpdate = ClosedGroupUpdate.fromProto(proto) { return closedGroupUpdate }
-        if let expirationTimerUpdate = ExpirationTimerUpdate.fromProto(proto) { return expirationTimerUpdate }
-        if let visibleMessage = VisibleMessage.fromProto(proto) { return visibleMessage }
-        return nil
+        let message: Message? = {
+            if let readReceipt = ReadReceipt.fromProto(proto) { return readReceipt }
+            if let sessionRequest = SessionRequest.fromProto(proto) { return sessionRequest }
+            if let typingIndicator = TypingIndicator.fromProto(proto) { return typingIndicator }
+            if let closedGroupUpdate = ClosedGroupUpdate.fromProto(proto) { return closedGroupUpdate }
+            if let expirationTimerUpdate = ExpirationTimerUpdate.fromProto(proto) { return expirationTimerUpdate }
+            if let visibleMessage = VisibleMessage.fromProto(proto) { return visibleMessage }
+            return nil
+        }()
+        if let message = message {
+            guard message.isValid else { return nil }
+            return message
+        } else {
+            return nil
+        }
     }
 }

SessionMessagingKit/Pipelines/SendingPipeline.swift

@@ -28,7 +28,7 @@ public enum SendingPipeline {
     }
 
     public static func send(_ message: Message, to destination: Destination) -> Promise<Void> {
-        guard message.isValidForSending else { return Promise(error: Error.invalidMessage) }
+        guard message.isValid else { return Promise(error: Error.invalidMessage) }
         guard let proto = message.toProto() else { return Promise(error: Error.protoConversionFailed) }
         let plaintext: Data
         do {