Parse contact sync messages

SignalServiceKit/src/Loki/Messaging/ContactParser.swift

@@ -0,0 +1,22 @@
+
+@objc public final class ContactParser : NSObject {
+    private let data: Data
+    
+    @objc public init(data: Data) {
+        self.data = data
+    }
+    
+    @objc public func parseHexEncodedPublicKeys() -> [String] {
+        var index = 0
+        var result: [String] = []
+        while index < data.endIndex {
+            let uncheckedSize: Int? = try? data[index..<(index+1)].withUnsafeBytes { $0.pointee }
+            guard let size = uncheckedSize else { break }
+            index += 1
+            let protoAsData = data[index..<(index+size)]
+            guard let proto = try? SSKProtoContactDetails.parseData(protoAsData) else { break }
+            result.append(proto.number)
+        }
+        return result
+    }
+}

SignalServiceKit/src/Messages/DeviceSyncing/OWSSyncContactsMessage.m

@@ -67,13 +67,15 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (nullable SSKProtoSyncMessageBuilder *)syncMessageBuilder
 {
+    NSError *error;
     if (self.attachmentIds.count > 1) {
         OWSLogError(@"Expected sync contact message to have one or zero attachments, but found %lu.", (unsigned long)self.attachmentIds.count);
     }
 
     SSKProtoSyncMessageContactsBuilder *contactsBuilder;
     if (self.attachmentIds.count == 0) {
-        SSKProtoAttachmentPointer *attachmentProto = [SSKProtoAttachmentPointer builderWithId:0];
+        SSKProtoAttachmentPointerBuilder *attachmentProtoBuilder = [SSKProtoAttachmentPointer builderWithId:0];
+        SSKProtoAttachmentPointer *attachmentProto = [attachmentProtoBuilder buildAndReturnError:&error];
         contactsBuilder = [SSKProtoSyncMessageContacts builderWithBlob:attachmentProto];
         __block NSData *data;
         [OWSPrimaryStorage.sharedManager.dbReadConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
@@ -90,7 +92,6 @@ NS_ASSUME_NONNULL_BEGIN
     }
     [contactsBuilder setIsComplete:YES];
     
-    NSError *error;
     SSKProtoSyncMessageContacts *contactsProto = [contactsBuilder buildAndReturnError:&error];
     if (error || contactsProto == nil) {
         OWSFailDebug(@"Couldn't build protobuf due to error: %@.", error);

SignalServiceKit/src/Messages/OWSMessageHandler.m

@@ -170,8 +170,9 @@ NSString *envelopeAddress(SSKProtoEnvelope *envelope)
         NSString *verifiedString =
             [NSString stringWithFormat:@"Verification for: %@", syncMessage.verified.destination];
         [description appendString:verifiedString];
+    } else if (syncMessage.contacts) {
+        [description appendString:@"Contacts"];
     } else {
-        OWSFailDebug(@"Unknown sync message type");
         [description appendString:@"Unknown"];
     }
 

SignalServiceKit/src/Messages/OWSMessageManager.m

@@ -1007,6 +1007,12 @@ NS_ASSUME_NONNULL_BEGIN
     } else if (syncMessage.verified) {
         OWSLogInfo(@"Received verification state for %@", syncMessage.verified.destination);
         [self.identityManager throws_processIncomingSyncMessage:syncMessage.verified transaction:transaction];
+    } else if (syncMessage.contacts) {
+        NSLog(@"[Loki] Received contact sync message.");
+        NSData *data = syncMessage.contacts.data;
+        ContactParser *parser = [[ContactParser alloc] initWithData:data];
+        NSArray<NSString *> *hexEncodedPublicKeys = [parser parseHexEncodedPublicKeys];
+        // TODO: Establish sessions
     } else {
         OWSLogWarn(@"Ignoring unsupported sync message.");
     }